Ch20: Antimicrobial Drugs, Antibiotics, Microbiology Definitions, Ch 10 Antimicrobial Treatment, Chapter 20, Microbiology Chapter 12 and 13, Microbiology Ch. 9 (p. 248 - 255), Micro Chapter 10, Microbiology Chapter 11 Physical and Chemical control of...
Polyenes: 2 examples
Polyenes mimic fungal lipids, bind to sterols. 1) Amphotericin-B 2) Nystatin.
Disruptor of cell membrane:
Polymyxin
14. Name a drug that targets the cellular membrane.
Polymyxin B and E
Name drugs that target the cell membrane
Polymyxin disrupts cytoplasmic membranes of Gram-negatives causing cell leakage; toxic to human cell membranes and only used on skin
Examples of drugs that affect the cell membrane
Polymyxins
Probiotics
Preparation of live microbes used as a preventive or therapeutic measure to displace or compete with potential pathogens.
Probiotics
Preparations of live microorganisms that are fed to animals and humans to improve intestinal biota
Identify antimicrobials that act by inhibiting protein synthesis
Tetracycline and macrolides (erthromycin)
Action of Antimicrobial Drugs:Inhibiting Protein Synthesis - Tetracyclines
Tetracycline interferes with the attachment of tRNA to mRNA ribosome complex
Examples of drugs that affect protein synthesis
Tetracycline, erythromycin, chloramphenicol
7. Identify which categories of drugs are most selectively toxic and why.
Tetracyclines
Which antibiotic has a side effect known to cause teeth discoloration in kids?
Tetracyclines
Explain a simple test one could do to determine if drug resistance was developing in a culture.
The Kirby Bauer test (disk diffusion) is used to determine if an organism is susceptible or resistant to a selection of antimicrobial agents. Lawn of bacteria is made on agar plate. Disks with. known concentrations of antimicrobial agents are added to agar. A "zone of inhibition" forms around the disk which can then be measured & compared against a standard table to determine if the organism is sensitive, intermediate, or resistant
Infection
The entry, establishment, & multiplication of pathogenic organisms within a host.
Reverse transcriptase (RT)
The enzyme possessed by retroviruses that carries out the reversion of RNA to DNA- a form of reverse transcription.
Microbial antagonism
The general effect that good microbes have against intruder microorganisms. Microbes in a steady, established relationship are unlikely to be displaced by incoming microbes
What is the effectiveness of a germicide determined by?
The germicide's effectiveness in destroying microbes.
thermal death point and role
Thermal death point: TDP the lowest temp required to kill all microbes in a sample in 10 minutes.
Define thermal death time and describe role
Thermal death time: TDT the shortest length of time required to kill all test microbes at a specified temp.
"Antibiotics don't work on colds." WHY?
They are NOT effective against VIRUSES (causative agent for colds)
What is good about antibiotics that inhibit nucleic acid synthesis?
They are all bactericidal.
Goal of antimicrobial chemotherapy
To administer a drug to an infected person, which destroys the infective agent without harming the host's cells
What is the main goal of antimicrobial therapy?
To destroy the infective agent and to be nontoxic to the host and produce no side-effects
Goal of antimicrobial drugs
To disrupt the cell processes or structures of bacteria, fungi, and protozoa and inhibit virus replication
Why is it better for a drug to be microbicidal than microbiostatic?
A microbicidal antibiotic is advantageous because it destroys the pathogen with no likelihood for future reproduction. In contrast, microbistatic antibiotics only inhibit growth as long as they are present, but when therapy is stopped, remaining microbes can resume reproductive activities.
Dry oven
A method of dry heat control that is used for heat-resistant items that do not sterilize well with moist heat, such as glassware and metallic instruments
Polymyxins
A mixture of antibiotic polypeptides from Bacillus polymyxa that are particularly effective against ram-negative bacteria.
Endemic
A native disease that prevails continuously in a geographic region.
Necrosis
A pathological process in which cells & tissues die & disintegrate.
Carrier
A person who harbors infections & inconspicuously spreads them to thers.
Asymptomatic carriers
A person with an inapparent infection who showns no symptoms of being infected yet is able to pass the disease agent to others.
Koch's postulates
A procedure to establish the specific cause of a disease. In all cases of infection: 1. The agent must be found 2. Inoculations of a pure culture must reproduce the same disease in animals 3. The agent must again be present in the experimental animal 4. A pure culture must again be obtained
Filtration
A method of microbial control in which liquid or gas is passed through a filter with sufficiently small pore size. No thermal damage is done, however, viruses are not eliminated.
Boiling water
A method of moist heat control used for disinfection and not sterilization.
Pasteurization
A method of moist heat control used to disinfect beverages. Heat is applied to liquids to kill potential agents of infection and spoilage, while retaining the liquid's flavor and food value. It does not kill endospores.
Steam under pressure
A method of moist heat control when pressure raises the temperature of steam. An autoclave is usually used, and all endospores are killed.
Nonionizing radiation, or ultraviolet rays
A method of radiation control that is not as penetrating as ionizing radiation. It is a powerful tool for destroying fungal cells and spores, bacterial vegetative cells, protozoa, and viruses
Ionizing radiation
A method of radiation control used for food and medical products. Its main advantages are speed, penetrating power, and no heat
True pathogens (primary pathogens)
A microbe capable of causing infection & disease in healthy persons with normal immune defenses.
Pathogen
A microbe that can cause disease in a susceptible individual
Virulence factor
A microbe's structures or capabilities that allow it to establish itself in a host & cause damage.
Name antifungal agents
Amphotericin B attaches to ergosterol (steriod found in fungal cell membrane); bacteria lack sterols so not susceptible; humans somewhat susceptible because chloesterol similiar to ergosterol (both steroid derivitives) Azoles inhibit ergosterol synthesis and disrupts cell membrane of fungi (ketocon-, flucon-,clotrim-, micon-)
Biota
Beneficial or harmless resident bacteria commonly found on and/ or in the human body.
Penicillnases
Beta lactamases; part of drug resistance to penicillin
Explain the significance of beta-lactamases and how they interact with antibiotics.
Beta-lactamases cleave the beta-lactam ring in the penicillin molecule, making the antibiotic ineffective
Halogen antimicrobial chemicals
Chemicals that are microbicidal and sporicidal with longer exposure. Includes fluorine, bromine, chlorine, and iodine
Fungistatic
Chemicals that inhibit fungal growth
Gaseous sterilants and disinfectants
Chemicals which block DNA replication and protein function, such as ethylene oxide and propylene oxide
Detergents
Chemicals which, when cationic, are more effective because the positively charged end binds well with the predominately negatively charged bacterial surface proteins.
Acids and alkalis
Chemicals with a very low or high pH which destroys or inhibits microbial cells. They are limited in applications due to their corrosive, caustic, and hazardous nature
Define-cidal. Compare the action of microbicidal and microbistatic agents, providing an example of each.
Cide: (CIDAL DOES NOT necessarily result in sterilization.)to kill, can be combined with other terms to define an antimicrobial agent aimed at destroying a certain group of microorganisms. Microbicidal: agents that can kill microorganisms. Ex: chemical agent and can be toxic to human cells. Example: harsh to be able to kill. Bactericide: destroy bacteria but no endospores. Fungicide: kill fungi-yeast hyphae. Virucide: inactive viruses. Sporocie: destroying endorspores. Can be toxic to human cells
Erythromycin: newer synthetics
Clarithomycin, azithromycin
Competitve inhibition
Control process that relies on the ability of metabolic anaolgs to control microbial growth by sucessfully competing with the necessary enzyme to halt the growth of the bacterial cells.
Halogens
Fluorine, bromine, chlorine, & iodine, a group of nonmetallic elements, all of which are found in goup VII of the periodic table. Highly effective components of disinfectants & antiseptics.
Sequelae
Form of long-term or permanent damage to the tissues or organs.
Lyophilization
Freezing & drying. A method of preserving microorganisms (& other substances) by freezing & then drying them directly from a frozen state.
What infection is the hardest to treat because the structure of the cells resemble ours so similarly?
Fungal Infections
Explain the significance of Beta lactamases
Genes carried on R-plasmid and inactivates Beta lactam drugs (penicillin)-breaks the bond
Sexually transmitted diseases (STDs)
Infections resulting from pathogens that enter the body via sexual intercourse or intimate, direct contact.
Systemic infection
Infections that invade many compartments & organs via the circulation. Occurring throughut the body.
Lymphadenitis
Inflamation of one or more lymph node.
Drugs that affect DNA/RNA?
Inhibit Replication and transcription, Inhibit Gyrase: Quinolones Inhibit RNA polymerase: Rifampin
What are the typical modes of action of antibiotics?
Inhibit cell wall synthesis, inhibit protein synthesis, inhibit nucleic acid synthesis, alter/inhibit membrane, inhibit folic acid (anti-metabolites)
Sporicide
Is an agent capable of destroying bacterial endospores. Sporical agent can also be a sterilant because it can destroy the most resistant of all microbes.
Virucide
Is any chemical known to inactivate viruses, especially on living tissue
Sanitization
Is any cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to safe levels. A sanitizer is a compound such as soap or detergent used to perform this task.
Sterilization
Is the destruction of all microbial life.
Decontamination
Is the mechanical removal of most microbes from an animate or inanimate surface.
Fungal enzyme of interest
Keratinases: degrade keratin on skin, nails, hair, e.g. RIngworm, athlete's foot, jock itch
3. Describe two methods for testing antimicrobial susceptibility.
Kirby Bauer Procedure and E-Test
Describe methods for testing antimicrobial susceptibility
Kirby-Bauer: zone of inhibition Tube dilution tests (MIC): the smallest concentration (highest dilution) of drug that visibly inhibits growth; more sensitive and quantitative than the Kirby-Bauer; useful in determining the effective dosage and providing a comparative index against other antimicrobials
Microbistatic
Materials used to control microorganisms in the body often have ____________ effects because microbial compounds can be highly toxic to human cells.
Focal infection
Occurs when an infectious agent breaks loose from a localized infection & is carried by the circulation to other tissues.
Mixed infection (Also known as synergistic infection)
Occurs when several different pathogens interact simutaneously to produce an infection.
Denature
Occurs when the bonds that maintain the secondary & tertiary structure of the protein are broken. Breaking these bonds will cause the protein to unfold or create random, irregular loops & coils.
Isoniazid
Older drug that targets the bacterial cell wall; used against M. tuberculosis.
Antimicrobials
all-inclusive term for any antimicrobial drug, regardless of its origin.
Narrow Spectrum (limited spectrum)
antimicrobials effective against a limited array of microbial types- for example, a drug effective mainly on gram positive bacteria
Broad Spectrum (extended spectrum)
antimicrobials effective against a wide variety of microbial types- for example, a drug effective against both gram-positive and gram negative bacteria
Chemotheraputic Drug
any chemical used in the treatment, relief, or prophylaxis of a disease
chemotherapy
any chemical used in the treatment, relief, prophylaxis of a disease
Fromite
Virtually any inanimate object an infected individual has contact with that can serve as a vehicle for the spread of disease.
Lypophilization
a combo of freezing and drying. Common method of preserving microbes and other cells in a viable state.
latency
a dormant stage for microbes, in which they can periodically become active and produce a recurrent disease
How can a metabolic analog molecule inhibit metabolism?
a enzymatic activity of a microbe can be competitively inhibited by a substance that closely resembles the normal substrate for the enzyme - stopping synthesis of essential metabolites
vector
a live animal that transmits an infectious agent from one host to another
AZT (Zidovudine)
a nucleotide analog reverse transcriptase inhibitor. It stops the action of reverse transcriptase in HIV, blocking viral DNA production
Antibiotics are common metabolic processes of
aerobic bacteria and fungi. produced to inhibit the growth of competing microbes in the same habitat
antimicrobials
all inclusive term for any antimicrobial drug regardless of its origin
Chloramphenicol
synthetic antimicrobial used only in dire situations - very toxic to humans. Inhibits protein synthesis by blocking peptide bonds in both prokaryotic & eukaryotic cells; suppresses bone marrow activity & causes irreversible damage;
Nystatin
topical treatment for fungal infections
prevalence
total number of exsisting cases with respect to the entire population
examples of indirect transmission
touching contaminated objects, air as a vehicle
examples of direct transmission
touching, kissing, sexual intercourse, vertical transmission
Quinine
treatment for malaria
Metronidazole
treats mild and severe protozoan intestinal infections
Antiparasitic
treats parasitic infections
nonpressurized steam:
tyndallization (cannot withstand high temps of autoclave)free flowing steam in chamber for 30-60 min for 3 days.
cell membrane
both gram positive and gram negative have cell membrane. Use a surfactant. Surfactant molecules break membrane lipids apart and mess up transport and proper respiration. Electron transport chain happens in cell membrane so it inhibits respiration. More permeable for entrance and exit.
cell wall:
break it apart. Damage. Good prevention for gram negative. Detergents and alcohols disrupt the cell wall.
What is the initial way to detect and possibly identify a bacteria or fungi?
by having a doctor directly examine the body fluids, sputum, or stool.
Polysporin
combination therapy similar to Neosporin but w/o neomycin
Penicillin plus B-Lactamase Inhibitor
combines penicillin with clavulanic acid which is a noncompetitive inhibitor of penicillinase (no antimicrobial activity of its own). Ex: Augmentin
What is competitive inhibition?
compete for active site on the enzyme
Discuss the uses of aldehyde agents
compounds containing terminal -CHO groups Formaldehyde (embalming/disinfection of surgical instruments) and Glutaraldehyde (dialysis machines)
pasteurization
heat is applied to liquids to kill potential agents of infection and spoilage, while at the same time retaining the liquids flavor and food value. Disinfection of beverage. Heat is applied to liquids to kill potential infectious agents. Do not kill endospores
What type of infections is Acyclovir used for? How is it able to maintain selective toxicity?
herpes virus infections; it maintains selective toxicity because it blocks viral DNA synthesis
What is preferred, a high or low toxic dose?
high, you want it high and the MIC low
mortality rate
measures the number of deaths in a population due to a certain disease
incidence
measures the number of new cases over a certain time period
Rise of Drug Resistance
microbes are gaining resistance faster than new drugs can be developed; 60% of hospital strains are resistant (MRSA & community acquired); drugs in animal feed to promote growth are increasing resistance
Drug resistance
microorganisms begin to tolerate a drug
Selective Toxicity
minimal or no effect on host cells but maximum effect against the infecting microorganism
nonliving reservoirs
nonliving, environmental sources in which human hosts are in regular contact with, such as soil and water
Prebiotics
nutrients that encourage the growth of beneficial microbes in the intestine
sporadic disease
occasional cases are reported at irregular intervals in random locales
Anti-fungal drugs that inhibit fungal metabolism
oral GRISEOFULVIN: stubborn cases of dermatophyte infections (jock itch, athlete's foot)
Discuss the uses of phenol agents
organic matter (vomit, blood and feces)
Chemotherapeutic drugs are described with regard to their
origin, range of effectiveness, and whether they are naturally produced or chemically synthesized.
Fosfomycin trimethamine
phosphoric acid effective as alternate treatment for UTIs: inhibit cell wall synth
antisepsis
sepsis aka infection. Against infection on own body. chemicals applied to body surfaces to destroy or inhibit vegetative pathogens. Example chemicals
Glycylcyclines
similar structure to tetracyclines; best known Tygacil; effective against certain antibiotic resistant bacteria (MRSA)
Define the terms sterilization, disinfection, sanitation, antisepsis, degermation, and pasteurization
sterilization: destruction of ALL microorganisms and viruses disinfection: reduction; nonliving tissue sanitation: to meet public health standards antisepsis: reduction; living tissue degermation: removal by mechanical means pasteurization: use of heat; food and beverages
Macrolides (Erythromycin)
structure - macrolide ring; inhibits protein synthesis by binding to ribosome, preventing ribosome from moving along mRNA to read message; most common prophylactic drug used; broad spectrum
antibiotics
substance produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms
Antibiotics
substances produces by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms
Abscesses
An inflamed, fibrous lesion enclosing a core of pus.
Primary infection
An initial infection in a previously healthy individual that is later complicated by an additional (secondary) infection.
Pathogenicity
An organism's potential to cause infection or disease. There are two kinds: true and opportunistic
Define "-static" and "-cidal"
"-static": inhibition but not complete destruction "-cidal": destruction
Amantadine targets what viral infection step?
(1) Entry/uncoating: influenza
Acylclovir targets what viral infection step?
(2) Viral synthesis: Herpes
Rifampicin targets what viral infection step?
(3) Assembly/maturation
Amphotericin-B
(Polyene) topical and systemic anti-fungal treatments
Other Antimicrobial Agents: Dyes, Acids, and Alkalis Dyes
*Dyes* are a primary source of certain drugs used in chemotherapy. But because aniline dyes such as crystal violet and malachite green are very active against gram-positive species of bacteria and various fungi, they are sometimes incorporated into solutions and ointments to treat skin infections (like ringworm). The yellow acridine dyes, acriflavine and proflavine, are sometimes utilized for antiseptics and wound treatment. Dyes have limited applications because they stain and have a narrow spectrum of activity. As for acids and alkalis, we know that conditions of very low or high pH can destroy or inhibit microbial cells. However, they are limited in applications due to their corrosive, caustic, and hazardous nature.
What are the three levels of chemical decontamination procedures?
*High-level* germicides kill endospores and, if properly used, are sterilants. Materials that necessitate high-level control include catheters, heart lung equipment, and implants. *Intermediate-level* germicides kill fungal (but not bacterial) spores, resistant pathogens such as the tubercle bacillus, and viruses. They are used to disinfect items (respiratory equipment, thermometers) that come in contact with mucous membranes but are noninvasive. *Low-level* germicides only eliminate vegetative bacteria, vegetative fungal cells, and some viruses. They are used to clean materials such as electrodes, straps, and pieces of furniture that the skin touch but are not mucous membranes.
Table 9.9 (cont'd)
*Phenol* (carbonic acid): Kills some bacteria, viruses, fungi; in high concentrations, it works by cellular poisons that disrupt cell walls, membranes, and proteins; in low concentrations, it works by inactivating certain critical enzyme systems. *Chlorhexidine*: Kills most bacteria, viruses, fungi; works by targeting both bacterial membranes where selective permeability is lost and proteins result in denaturation. *Alcohol*: Kills most bacteria, viruses, fungi; concentrations above 50% dissolve membrane lipids and disrupt cell surface tension and compromise membrane integrity. *Detergents*: Kills some bacteria, viruses, fungi; positively charged end of the molecule binds well with the predominately negatively charged bacterial surface proteins. Long, uncharged hydrocarbon chain allows the detergent to disrupt the cell membrane. Cell membrane loses selective permeability, causing cell death. *Heavy metal compounds*: Kills some bacteria, viruses, fungi; mercury, silver, and other metals exert microbial effects by binding onto functional groups of proteins and inactivating them.
Toxemias
Condition in which a toxin (microbial or otherwise) is spread throughout the bloodstream.
Azoles
Five-membered heterocyclic compounds typical of histidine, which are used in antifungal therapy.
Susceptibility Testing
- to predict the success or failure of antibiotic therapy (in vivo) in the body - tests are performed (in vitro) outside the bdy that measure the growth response of the organism to particular drug(s) -results should guide antibiotic choice - results of susceptibility testing should be combined with clinical info & experience when selecting appropriate antibiotic
Antiviral drugs are typically more difficult to develop & maintain selective toxiciity. Give 2 reasons why.
1) because the virus replicates in the hosts cells using host cells genetic & metabolic mechanisms its hard to target the virus without damaging the host cell machinery 2) Most drugs are unable to affect latent or extracellular viruses
The failure of an antimicrobial drug can be due to what?
-inability f the drug to diffuse into that body compartment -resistant microbes in the infection that didn't make it into the sample collected for testing -an infection caused by more than one pathogen (mixed), some of which are resistant to the drug.
Sulfa drugs
/Sulfonamides: Sulfanilamide + Trimethoprim. Analog of substrates in folic acid pathway. Sulfa drugs also inhibit pathway enzymes for DNA/RNA synthesis (competitive inhibition for active site)
Identify some heavy metal controls
1% silver nitrate thimerosal copper
Inhibitors of folic acid pathway
1) Sulfa drugs/sulfonamides + 2) Trimethoprim =synergistic treatment
Isoniazid (INH)
1) VERY narrow spectrum, 2)targets Mycobacterium cell wall (inhibits mycolic acid synthesis), 3)Combo therapy w/rifampin=synergistic against TB, 4) RESISTANCE a problem
Characteristics of Ideal antimicrobial drug.
1) selective toxicity 2) microbicidal, not microbistatic 3) Soluble 4) Remains potent long enough to act 5) Doesn't lead to antimicrobial resistance 6) Complement's hosts defenses 7) Remains active in tissues/body fluids 8) Easily delivered to site of infection 9) Reasonably priced 10) Doesn't cause other health problems like allergies or predispose to other infections
It is harder to treat a patient with a fungal, protozoan, or helminth parasite than a bacterial infection. Give 2 reasons why that is true.
1) since they are eukaryotes they use the same mechanisms to synthesize proteins & nucleic acids so it hard to find a point of selective toxicity 2) fungal infections are becoming more frequent as opportunistic infections in immunosuppressed individuals
Chemical structures of Penicillins
1)All have ß-lactam ring. 2)R-group dictates microbial activity: If it's -CH₂, Penicillin G (injection). If it's -OCH₂, Penicillin V (oral)
Bacitracin
1)Bacillus subtilis; 2)topical application due to toxicity; 3)Narrow spectrum (Gram+); 4)1/3 components of Neosporin
Polymyxins
1)Bacillus-originating antimicrobial that attaches to membrane phospholipids. 2)Causes leakage especially in Gram-neg bacteria (narrow spectrum). 3)Toxicity issues wrt kideys, nerves.
What are the 5 main targets of antimicrobial drugs?
1)Cell wall synthesis, 2)Cell membrane function, 3)Nucleic acid synthesis, 4)Protein synthesis, 5)Action as antimetabolites
Cephalosporins
1)Cephalosporium acremonium (mold); 2)1/3 of all antibiotics administered; 3)Resistant to most ß-lactamases; 4)Relatively broad-spectrum; 5)2nd/3rd/4th/ gens more effective against Gram-neg; 6)Fewer toxic reactions
Vancomycin
1)Glycopeptide, 2)Narrow spectrum, 3)Toxic (difficult to administer, 4)Considered last line against antibiotic-resistant pathogens, e.g. MRSA
Penicillins
1)block synthesis of peptidoglycan (cause wall to lyse), 2)do not penetrate outer membrane and are less effective against gram-negative bacteria (unless broad spectrum penicillin), 3)Now semi-synthetic, 4)ALL have ß-lactam ring, 5)Amoxicillin, ampicillin=broad spectrum examples, 6) LITTLE host toxicity
What are the 4 major groups of Antimicrobial drugs?
1. Antibacterial, 2. Antifungal, 3. Antiparasitic, 4. Antiviral
Anti-parasitic drugs: 3 types
1. Antimalarial 2. Antiprotozoan 3. Antihelminthic
Four ways to acquire normal microbiota
1. birth canal 2. food 3. breathing 4. natural succession
Three modes of action against viruses
1. Barring penetration of the virus into the host cell 2. Blocking the transcription and translation of viral molecules 3. Preventing the maturation (assembly) of viral particles
Tetracyclines
1. Blocks protein synth via blocking attachment of tRNA to A site. 2. Broad-spectrum/bacteriostatic. 3. CHEAP: used in animal feed. 4. Examples: Doxycycline & minocycline (orals)
Erythromycin
1. Broad spectrum/bacteriostatic. 2. Blocks translocation by attaching to 50s. 3. LOW toxicity (given to kids). 4. Taken orally for Mycoplasma pneumonia, legionellosis, Chlamydia, pertussis diptheria 5. Prophylactic prior to intestinal surgery
Penicillinase-resistant penicillins
1. Carbapenems: very broad spectrum 2. Monobactam: Gram-negative, 3. Methicillin
Five targets for antibiotics
1. Cell wall 2. Cell membrane 3. Nucleic acid synthesis 4. Protein synthesis 5. Metabolic processes (folic acid productions)
Four targets for antimicrobial agents
1. Cell wall 2. Cell membrane 3. Protein and nucleic acid synthesis 4. Protein function
Infection cycle of Animal Virus: 5 steps
1. Entry/uncoating 2. Viral synthesis 3. Assembly/maturation 4. Release 5. Stimulation of Immune System
New classes of antibiotics
1. Fosfomycin trimethamine 2. Synercid 3. Oxazolidinones (Linezolid)
Five mechanisms of drug action
1. Inhibition of cell wall synthesis 2. Inhibition of nucleic acid structure and function 3. Inhibition of protein synthesis 4. Interference with cell membrane structure or function 5. Inhibition of folic acid synthesis (metabolism)
6. List the five major targets of antimicrobial agents.
1. Inhibition of cell wall synthesis, 2. inhibition of nucleic acid, 3. inhibition of protein synthesis, 4. interference with cell membrane structure or function, 5. inhibition of folic acid synthesis
Four factors that affect the germicidal activity of chemicals
1. Nature of microorganisms 2. Degree of contamination 3. Time of exposure 4. Strength and chemical action of the germicidal
Two strategies used by microbes to resist drugs
1. Prevent access of the drug to the target site 2. Alter the nature of the target site
Six factors to consider when choosing a microbicidal chemical
1. Rapid action, even in low concentrations 2. Solubility in water or alcohol and long term stability 3. Broad spectrum microbicidal action without being toxic to human and animal tissues 4. Penetration of inanimate surfaces to sustain a cumulative or persistant action 5. Noncorrosive or non staining properties 6. Affordibility and ready availability
Six things to consider when choosing an anti microbial drug
1. Solubility in water and long term stability in the host 2. Broad spectrum microbicidal action without being toxic to the host's cells 3. Sustain a cumulative or persistant action and not be broken down or excreted too soon 4. Resistance to becoming inactivated by organic matter; remains active and potent in the host 5. Affordability and ready availability 6. Works with the host's immune system; does not cause allergies
Two ways cells acquire drug resistance
1. Spontaneous mutations in critical chromosomal genes 2. Acquisition of entire new genes or sets of genes via transfer from another species (plasmids called resistance factors)
Chloramphenicol
1. Streptomyces venezuelae. 2.Broad-spectrum/bacteriostatic. 3. Blocks peptide bond formation (50s). 4. No longer derived from natural source. 4. Restricted uses due to toxicity: anemias, bone marrow damage. 5. Treats Typhoid fever, brain abcesses, rickettsial & chlamydial infections
Aminoglycoside antibiotics (3)
1. Streptomycin 2. Neomycin 3. Kanomycin
Six factors that affect death rate
1. The number of microorganism 2. The nature of the microorganisms in the population 3. The temperature and pH of the environment 4. The concentration of the agent 5. The mode of action of the agent 6. The presence of solvents, interfering organic matter, and inhibitors
Three things in regards to which chemotherapeutic agents are described
1. Their origin 2. Their range of effectiveness 3. Whether they are produced naturally or chemically synthesized
Two origins of antibiotics
1. They are common products of aerobic bacteria and fungi 2. Chemists have created new drugs by altering the structure of naturally occurring antibiotics
Three applications of ultraviolet radiation
1. Usually disinfection rather than sterilization 2. Hospital rooms, operation rooms, schools, food prep areas, dental offices 3. Treats drinking water and purifies liquids
5 Mechanisms of antimicrobial resistance
1. alteration of drug target, e.g. different membrane 2. alteration of membrane permeability (Tet^r) 3. Development of enzymes that inactivate the drug (penicillinases) 4. Development of alternate synthetic pathways 5. Exposure to microbes w/ resistance genes (transformation, conjugation, transduction)
Four ways normal flora helps us
1. exclude colonization of potential pathogens 2. provide some nutrition to the host 3. can improve host nutrition 4. immune stimulation
Five diseases associated with differences in gut biota
1. heart disease 2. asthma 3.autism 4. rheumatoid arthritis 5. thoughts, moods, and propensity for mental illness
Four results of the human microbiome project
1. human cells contain 22 thousand protein encoding genes; microbes that inhabit humans contain 8 million 2. we have a lot of microbes in places we used to think were sterile 3. all healthy people harbor potentially dangerous pathogens, but in low numbers 4. more work is being done to look at these microbes
Problems > antimicrobial resistance?
1. inappropriate usage 2. exposure to sub-optimal levels of chemical 3. exposure to microbes carrying resistance genes
Two benefits of normal biota
1. influence the development of organs 2. prevent the overgrowth of harmful microorganisms
Differentiate between two types of radiation control methods, providing an application of each.
1. ionizing radiation: if the radiation ejects orbital electrons from an atom, it causes ions to form (gamma rays, x rays, high-speed electrons). Radiation ejects orbital electrons from an atom, causing ions to form. Causes the most damage to proteins. COLD sterilization is used for materials sensitive to heat or chemicals. Breaks DNA. 2. Nonionizing radiation: exemliefied by ultraviolet, excites atoms by raising them to a higher energy state, but it does not ionize them. Leads to the formation of abnormal bonds within molecules such as DNA and is source of mutations. Excites atoms, raising them to higher energy state. Leads to the formation of abnormal bonds (pyrimidine dimers) within molecules such as DNA (T-T or C-C)
Four ways to prevent drug resistance
1. limit drug use 2. proper drug use 3. narrow range antibiotics 4. multiple drug treatments
Three steps to the process of infection and disease
1. microbes eventually settle in a particular target organ and continue to cause damage at the site 2. frequently weakens host tissues 3. accumulated damage leads to cell and tissue death
most resistant to least resistant
1. prions 2. protozoan cysts 3. fungal spores 4. gram pos. bacteria
Four portals of exit
1. secretion 2. excretion 3. discharge 4. sloughed tissue
Eight places where resident flora are found in/on our bodies
1. skin 2. eyes 3. nose 4. mouth 5. intestinal tract 6. vagina 7. urethra 8. respiratory tract
Five portals of entry for pathogens
1. skin, mucosal membranes 2. gastrointestinal 3. respiratory 4. urogenital 5. placental
Explain four different methods of moist heat control.
1. steam under pressure: autoclave. Pressure cooker. 121 degrees C and 15 psi. surgical equipment. 2. nonpressurized steam: tyndallization (cannot withstand high temps of autoclave)free flowing steam in chamber for 30-60 min for 3 days. 3. pasteurization: heat is applied to liquids to kill potential agents of infection and spoilage, while at the same time retaining the liquids flavor and food value. Disinfection of beverage. Heat is applied to liquids to kill potential infectious agents. Do not kill endospores 4. Boiling water; 100 degrees C. only disinfecting something.
What are the three important things to know before starting antimicrobial therapy?
1. the nature of the microorganism causing the infection. 2. the degree of the microorganism's susceptibility (sensitivity) to the various drugs. 3. the overall medical condition of the patient.
Four ways antimicrobials affect the body
1. toxicity to organs 2. allergies 3. disruption of normal flora 4. other adverse effects
Four new approaches to antimicrobials
1. using bacteriophages 2. targeting iron-scavenging capabilities 3. RNA silencing 4. slow down viruses by altering non-mutating host proteins
Boiling water
100 degrees C. only disinfecting something
Assess Your Progress
13. Name the desirable characteristics of chemical control agents. Rapid in low concentrations, soluble in water or alcohol with long-term stability, broad-spectrum microbial action without being toxic to humans or animals, penetration of intimate surfaces, resistance to becoming inactivated by organic matter, noncorrosive or nonstaining properties, sanitizing and deodorizing properties, affordability and availability. 14. Discuss chlorine and iodine and their uses. Both chlorine and iodine are used to (slowly) kill spores as well as all other microbes. Chlorine works by combining with water and releasing hypochlorous acid, which denatures enzymes permanently and suspends metabolic reactions. Iodine works by interfering with metabolic functions as well as the hydrogen and disulfide bonding of proteins. 15. List advantages and disadvantages to phenolic compounds. The advantages of phenolic compounds is that they remain one standard against which other (less toxic) phenolic disinfectants are rated. The disadvantage is that phenolic compounds are toxic, which makes them dangerous to use as antiseptics. 16. Explain the mode of action of chlorhexidine. Chlorhexidine works by targeting both bacterial membranes, where selective permeability is lost, and proteins, resulting in denaturation. 17. Explain the applications of hydrogen peroxide agents. Hydrogen peroxide can be used as an antiseptic for skin, wounds, and mouth washing. It can also treat infections caused by anaerobic bacteria. 18. Identify some heavy metal control agents. Microbes can develop resistance to metals. 19. Discuss the disadvantages of aldehyde agents. Glutaraldehyde is somewhat unstable with increased pH and temperature, and formaldehyde is extremely toxic and irritating to skin and mucous membranes. 20. Identify applications for ethylene oxide sterilization. Ethylene oxide is used to disinfect plastic materials and delicate instruments. It can also be used to sterilize syringes, surgical supplies, and medical devices that are prepackaged.
Antifungal drugs: target plasma membrane
2 groups: Polyenes, Azoles.
About how many different antimicrobial drugs are there?
260 which are classified in 20 drug families
incinerators
800- 6500 degrees C, used for needles, beeding, tissue samples, could kill endospores
Quiz question: What are the four desirable qualities of a germicide:
: Low toxicity, fast acting, water soluble, broad to a point but also specific, penetrate cell membrane.
What is the natural function of antibiotics?
Increase their resources by reducing competition for nutrients and space
Formalin
A 37% aaqueous solution of formmaldehyde gas; aa potent chemical fixative & microbicide.
SKIN CANCER
A and G are purines.... C and T are pyrine. UV light breaks bonds and causes c to bind with t irregularly. When usually a binds with t and c binds with g. This results in mutation. Mutation is any kind of change in the DNA sequence. If the mutation happened in a gene that was important in gene cell replication than you can get cancer.
Endotoxin
A bacterial toxin that is not ordinarily released (as in exotoxin). Can cause severe shock & fever.
Oligodynamic action
A chemical having antimicrobial activity in minuscle amounts. Example: Certain heavy metals are effective in a few parts per billion..
Hydrogen peroxide
A chemical in which oxygen forms free radicals which are highly toxic and reactive to cells. It is bactericidal, virucidal, fungicidal, and in higher concentrations, sporicidal
Sporicide
A chemical that can destroy bacterial endospores
Fungicide
A chemical that can kill fungal spores, hyphae, and yeasts
Bactericide
A chemical that destroys bacteria (not endospores)
Alcohols (ethanol and isopropyl only)
A chemical that does not destroy bacterial spores at room temperature, but can destroy resistant vegetative forms
Virucide
A chemical that inactivates viruses
Chlorhexidine
A chemical that targets cell membranes and protein structure. It is mild, has low toxicity, and rapid action. It is used for preparing skin for surgery and an obstetric antiseptic
Phenol
A chemical that uses lower concentration; it inactivates certain critical enzyme systems
Phagocytes
A class of whire blood cells capable of engulfing other cells & particles.
Aminoglycosides
A complex group of drugs derived from soil actinomycetes that impairs rinosome function & had antibiotic potential.
Pandemic Occurs
A disease afflicting an increased proportion of the population over a wide geographic area (often worldwide).
Gentamicin
A drug that is less toxic and used for gram-negative rods
Streptomycin
A drug used for the bubonic plague and tularemia; it is also a good antituberculosis agent
Tetracyclines
A group of broad-spectrum antibiotics with a complex 4-ring structure.
Actinomycetes
A group of filamentous, fungus like bacteria.
Leukocidins
A heat-labile substance formed by some pyogenic cocci that impairs & sometimes lyses leukocytes.
Hemolysins
A iological agent that iss capable of destroying red blood cells & causing the release of hemoglobin. Many bacterial paathogens produce exotoxins that act as hemolysins.
Daptomycin
A lipopetide antibiotic that disrupts the cytoplasmic membrane.
Leukopenia
A lower then normal leukocyte count in the blood that can be indicative of blood infection or disease.
Incineration
A method of dry heat control that ignites and reduces microbes to ashes and gas
Adhesion
A process by which microbes gain a more stable foothold on host tissues. It is dependant on binding between specific molecules on both the host and the pathogen. A particular pathogen is limited to only those cells and organisms to which is can bind. Once attached, a pathogen can invade body compartments
Prodromal stage
A short period of mild symptoms occuring at the end of the period of incubation. Indicates the onset of disease.
Granulomas
A solid mass or nodule of inflammatory tissue containin modified macrophages & lymphocytes. Usually a chronic pathologic process of diseases such as tuberculosis or syphilis.
What is a tinctures solution?
A solution containing pure alcohol or water-alcohol as the solvent.
What is an aqueous solution?
A solution containing pure water as the solvent.
axenic
A sterile state such as aa pure culture. An axenic animal is born & raised in a grem-freeee enviroment.
Epidemic
A sudden & simultaneous outbreak or increase in the number of cases of disease in a community.
Surfactants
A surface-active agent that forms a water-soluble interface. Examples: detergents, wetting agents, dispersing agents, & surface tension depressants.
Acyclovir
A synthetic purine analog that blocks DNA sunthesis in certain viruses, particularly the herpes simplex viruses.
Exotoxin
A toxin (usually protein) that is secreted & and acts upon a specific cellular target.
Portal of Entry
A way by which a microbe enters the tissues of the body, usually by a cutaneous or membranous boundary. It is normally the same anatomical regions that support normal biota.
Lesion
A wound, injury, or some other pathologic change in tissues.
1. State the main goal of antimicrobial treatment.
Administer a drug to an infected person, which destroys the infective agent without harming the host's cells
Parenterally
Administering a substance into the body compartment other then through gastrintestinal tract, such as via intravenous, subcutaneous, intramuscular, or intramedullary injection.
How do drugs target the cell wall of bacteria?
Active cells must constantly synthesize new peptidoglycan and transport it to the proper place in the cell envelope. These drugs react with one or more of the enzymes required to complete this process.
Identify one example of a fluroquinolone and what the drug targets
Acts against prokaryotic enzymes required for DNA replication: Levaquin and Ciprofloxacin
Identify advantages and disadvantages of cold treatment
Advantage: slow growth of cultures and microbes in food during processing and storage. Retards activities of most microbes. -70 to -135 degrees C. pathogens able to survive several months in refrigerator (staphylococcus aureus, clostridium, streptococcus yeasts, molds, viruses. Some microbes are killed by cold temps but most are not adversely affected by gradual cooling long-term refrig or deep freezing.
Identify which cell wall antibiotics are affected by beta-lactamases and which are not in the beta lactam category.
Affected by beta-lactamases: Penicillin, Cephalosporins, Carbapenems Not Affected by beta-lactamases: Polypeptide Antibiotics that interfere with cell wall synthesis & Antimycobacterial Antibiotics
Name the desirable characteristics of chemical control agents
Affects cell walls, cytoplasmic membranes, proteins or DNA; often more effective against enveloped viruses and vegetative cells of bacteria, fungi and protozoa
Bacteristatic
Agents that prevent the growth of bacteria on tissues or on objects in the environment.
Who is credited with discovering antibiotics and how did they make their discovery?
Alexander Fleming discovered antibiotics by accident when culture plates became contaminated with a mold. He noticed that bacterial growth was inhibited around the areas of mold growth, leading to the discovery of penicillin
Antimicrobials
All-inclusive term for any antimicrobial drug, regardless of its origin
22. Distinguish between drug toxicity and allergic reactions to drugs.
Allergic- heightened immunosensitivity, drugs acts as an antigen Toxicity- foreign chemicals harm human tissue
What is a primary problem wrt semi-synthetic Penicillins?
Allergies and resistant strains of bacteria
List cellular or structural mechanisms that microbes use to resist antimicrobials
Alter target of drug so it binds less effectively; alter their metabolic chemistry (resist sulfonamides by stopping folic acid synthesis and absorbing from environment); pump antimicrobial drug out of the cell before it can act via efflux pumps; growing in biofilms stop drug diffusion reduces the effectiveness of drugs
Drugs that are Protein Synthesis Inhibitors
Aminoglycosides (Streptomycin, Neomycin) Macrolides (Erythromycin) Tetracylines (Tetracycline, oxytetracycline)
Drugs that affect Protein Synthesis Inhibitors Acting on Ribosomes: 30s Subunit?
Aminoglycosides (gentamicin, streptomycin), Tetracyclines, Glycylcyclines
Polyenes are commonly used to treat fungal infections. Name 1 common polyene used & how it works to destroy the fungal organism. Is selective toxicity high or low? Why?
Amphotericin B most commonly used. It target the sterol, ergosterol in the plasma membrane by interrupting biosynthesis causing the membrane to become excessively permeable & killing the cell. Humans somewhat susceptible because cholesterol if similar to egosterol.It has a high toxicity to the kidneys which limits its use. Nystatin is a topical form used to treat candidiasis.
Leukocytosis
An abnormally large number of leukocytes in the blood, which can be indicative of acute infection.
Drug resistance
An adaptive response in which microoranisms begin to tolerate an amount of drug that would ordinarily be inhibitory.
Drug resistance
An adaptive response in which microorganisms begin to tolerate an amount of drug that would ordinarily be inhibitory
Germicide
An agent lethal to non-endospore-forming pathogens.
Biological vector
An animal that not only transports an infectious agent but plays a role in the life cycle of the pathogen, serving as a site in which it can multiply or complete its life cycle. It is usually an alernate host to the pathogen.
Mechanical Vector
An animal that transports an infectious agent but is not infected by it, such as houseflies whose feet become contaminated with feces.
Vector
An anmial that transmits infectious agents from one host to another, usually biting or piercing arthropod like the tick, mosquito, or fly. Infectious agents can be conveyed mechanically by simple contact or biologically whereby the parasite develops in the vector.
Amphotericin B
An anti-fungal drug in the nystatin group that is used topically and internally
Nystatin
An anti-fungal drug in which polyenes bind membrane (not entirely selective.) It affects cell stability via ergosteral
Fluconazole
An anti-fungal drug used in selected patients for AIDS-related mycoses
Ketoconazole
An anti-fungal drug used orally and topically for cutaneous mycoses, vaginal and oral candidiasis, and some systemic mycoses
Ribavirin
An anti-viral drug that blocks RNA synthesis
Acyclovir
An anti-viral drug that disrupts herpes virus replication. It has a nucleoside analog (looks like adenine or guanine)
Amantadine
An anti-viral drug that inhibits the penetration of influenza A virus
mode (or mechanism) of action
An antimicrobial agent's adverse effect on cells
Intracellular survival
An antiphagocytic factor in which pathogens can survive inside phagocytes after ingestion
Leukocidins
An antiphagocytic factor that is toxic to white blood cells
Extracellular surface layer
An antiphagocytic factor that makes it difficult for the phagocyte to engulf the pathogen
UV Exposure
An early form of microbial control which included exposing items to sunlight
Mechanical
An early form of microbial control which included filtration of liquids
Heat
An early form of microbial control which included fire and burning of items
Biological
An early form of microbial control which included salting, smoking, and pickling foods
Chemical
An early form of microbial control which included storage of liquids in copper and silver
Explain the concept of selective toxicity
An effective antimicrobial agent that must be more toxic to a pathogen than a pathogens host; drugs with excellent selective toxicity block the synthesis of the bacterial cell wall (penicillins); human cells lack the chemical peptidoglycan and are unaffected by the drug
Beta-lactamases
An enzyme secreted by certain bacteria that cleaves the beta-lactam ring of pinicillin & cephalosporin & thus provides for resistance against the antibiotic.
Penicillinase
An enzyme that hydrolyzes penicillin; found in penicillin-resistant strains of bacteria.
Nosocomial infections
An infection not present upon admission to a hospital but incurred while being treated there.
Superinfection
An infection occurring during antimicrobial therapy that is caused by an overgrowth of drug-resistant microorganisms.
Secondary infection
An infection that compounds am preexisting one.
Asymptomatic (subclinical)
An infection that produces no noticeable symptoms even though the microbe is active in the host tissue.
Zoonosis
An infectious disease indigenous to animals that humans can aquire through direct or indirect contact with infected animals.
Noncommunicable
An infectious disease that does not arrive through transmission of an infectious agent from host to host.
Pneumonia
An inflamation of the lung leading to accumulation of fluid & respiratory compromise.
What is a superinfection & what can cause one?
An overgrowth of bacteria or fungal microorganisms not affected by the antibiotic being used for treatment; can happen when using a broad spectrum antibiotic that destroys normal microbiota that normally keep pathogenic microbes in check
Fuzeon
Anti-HIV drug that inhibits viral attachment to host cells.
Echinocandins
Anti-fungal drugs that inhibit cell wall synthesis, and are used against candida and aspergillus infections
Clotrimazole and miconazole
Anti-fungal drugs used mainly as topical ointments for infections in the skin, mouth, and vagina.
Azoles
Anti-fungal drugs which inhibit ergosterol synthesis
Fosfomycin trimthamine
Antibiotic that inhibits an enzyme necessary for cell wall synthesis. Effective ass an alternate treatment for urinary tract infections caused by enteric bacteria.
Chloramphenicol
Antibiotic that inhibits protein synthesis by binding to the 50s subunitm of the ribosome.
Vancomycin
Antibiotic that targets bacterial cell wall; used often in antibiotic resistant infections. Effective in treating staphylococcal infections in cases of penicillin & methicillin resisttance or in patients with an allergy to penicillins.
Sulfonamides
Antimicrobial drugs that interfere with essentialn metabolic process of bacteria & some fungi.
Kirby Bauer test
Antimicrobial susceptibility testing. It is used in standardized conditions. The zone of inhibition is looked at; a larger zone indicates more susceptible, while a smaller zone indicates more resistance
Narrow spectrum
Antimicrobials effective against a limited array of microbial types
Narrow Spectrum (limited spectrum)
Antimicrobials effective against a limited array of microbial types- for example, a drug effective mainly on gram positive bacteria.
Broad spectrum
Antimicrobials effective against a wide variety of microbial types
Broad Spectrum (extended spectrum)
Antimicrobials effective against a wide variety of microbial types- for example, a drug effective against both gram-positive & gram negative bacteria.
Amantadine
Antiviral agent used to treat influenza; prevents fusion & uncoating of virus.
Sign
Any abnormality uncovered upon physical diagnosis that indicates the presence of disease. Is an objective assessment of disease.
Pathogen
Any agent (usually a virus, bacterium, fungus, protozoan, or helminth) that cause a disease.
Virulence factor
Any characteristic or structure of the microbe that contributes to its virulence
Chemotherapeutic drug
Any chemical used in treatment, relief, or prophlaxis of a disease.
Sterile
Any material that has been subjected to the process of Sterilization (process that destroys or removes all viable microorganisms) is said to be ____________.
Asepsis
Any practice that prevents the entry of infectious agents into sterile tissues and thus prevents infection.
Chronic infections
Any process or disease that persist over a long duration.
Inhibitors of cell wall synthesis:
BICVP: Bacitracin, Isoniazid, Cephalosporins, Vancomycin, Penicillins
What 3 antibiotics are in Neosporin? What are their modes of action? Why should they only be applied after a scab has formed & not taken orally?
Bacitracin (polypeptide antibiotic that interferes with linear stands in peptidoglycan, Polymyxin (affects permeability of plasma membrane), & Neomycin (interferes with protein synthesis). Polymyxins are nuerotoxic so it can't be taken orally. Polypeptide antibiotics are highly toxic if taken orally.
What is the major source of antibiotics?
Bacteria and fungi
Identify the sources for most currently used antimicrobials
Bacteria in the genera Streptomyces and Bacillus; molds in the genera Penicillium and Cephalosporium
Why do drugs that act on bacterial & fungal membranes generally have high toxicity?
Bacterial and Fungal cell membranes are made up of phospholipids just like the human cell membranes. And this is why antibiotics that act on cell membranes are not that specific in their toxicity.
Highest resistant forms of microbes
Bacterial endospores, prions
Narrow spectrum is to __________ as broad spectrum is to ___________.
Bactericidal; bacteriostatic
There are two basic types of antibiotics, Bacteriostatic and Bactericidal. What is the difference?
Bacteriostatic antibiotics inhibit the replication of bacteria, but if the antibiotic is removed then the bacteria can begin to grow again. (MIC: Minimum inhibitory concentration. Drug concentration at which bacteria growth is stopped.) Bactericidal antibiotics permanently inhibit the ability of a bacteria to replicated. (MBC: Minimum Bactericidal Concentration. Concentration at which bacteria is killed.)
Why should you not use Colistin as a first line of defense? (It is a polymyxin)
Because it is HIGHLY nephrotoxic. Good as a last resort.
Why shouldn't rifampin be used alone?
Because many Gram(-) are resistant due to it not crossing their outer membrane. Others will develop a resistance by altering its target.
What is the mode of action of Beta-lactam ring based antibiotics? Are they bacteriostatic or bactericidal?
Bind to serine proteases (regulatory enzymes for cell wall synthesis). Prevent their action. Bactericidal.
What is the mechanism of action of Vancomycin?
Binds to peptidoglycan precursors and inhibits them from forming. Only effective against Gram(+) (Too large to pass through the outer membrane).
Tetracyclines: what do they do?
Block attachment of tRNA on A acceptor site∴inhibiting protein synthesis
Amantadine (Tamiflu)
Blocks entry of the influenza virus by interfering with fusion of the virus with the cell membrane. Needs to be given within 1st 72hrs before virus replicates and spreads
Chloramphenicol: what does it do?
Blocks formation of peptide bonds (50s subunit) ∴inhibiting protein synthesis.
Erythromycin: what does it do?
Blocks translocation movement by attaching to 50s subunit ∴inhibiting protein synthesis
Irradiation
Bombardment of radiation, at the cellular level. The application of radiant energy for diagnosis, therapy, disinfection, or sterilization.
Mebendazole
Broad spectrum anti-parasitic drugs
8. Distinguish between broad-spectrum and narrow-spectrum antimicrobials, and explain the significance of the distinction.
Broad-spectrum- effective against more that one group of bacteria Narrow-spectrum- target a specific group
Inhibitors of protein synthesis:
CEST: Chloramphenicol, Erythromycin, Streptomycin, Tetracyclines
Ciprofloxaxin: Inhibitor of NA synthesis
CIPRO: inhibits DNA replication enzymes. Wide applications: respiratory, UT infections, stds, anthrax (broad-spectrum/bacteriostatic)
Identify advantages and disadvantages of cold and desiccation
COLD advantage: halts growth disadvantage: some microbes can multiply;bacteriostatic (decrease microbial metabolism, growth and reproduction) rather than bactericidal DESICCATION advantage: drying inhibits growth because of removal of water disadvantage: bacteriostatic (decrease microbial metabolism, growth and reproduction) rather than bactericidal
List major targets of action of antiviral drugs
Can target unique aspects of viral metabolism (viral assembly and release); Amantadine prevents viral uncoating upon entry into host cell; Protease (enzymes that break peptide bonds in proteins) inhibitors interfere with an enzyme HIV and hepatitis needs in its replication cycle
Communicable
Capable of being transmitted from one individual to another.
antimicrobial
Capable of destroying or inhibiting the growth of disease-causing microorganisms
Pathologic
Capable of inducing physical damage to the host.
Intoxications (botulism)
Caused by ingestion of toxins.
Antisepsis
Chemical agents called antiseptics are applied directly to exposed body surfaces (skin and mucus membranes), wounds, and surgical incisions to destroy or inhibit vegative pathogens.
Microbicide
Chemical agent that kills microorganisms.
Germicide and microbicide
Chemical agents that kill microorganisms
Opportunistic pathogens
Cause disease when the host's defenses are compromised or when they become established in a part of the body that is natural to them.
Action of Antimicrobial Drugs: Injure Plasma Membrane
Cause loss of selective permeability;
Drugs that affect Cell Membrane?
Causes loss of selective permeability: Polymyxins, Daptomycin
Name categories of cellular targets for physical and chemical agents
Cell wall Cell membrane Cellular synthesis Nucleic acids Proteins
Chitin
Cell wall of a fungus
Universal precautions (UPs)
Centers for disease control & prevention guidlines for health care workers regarding the prevention of disease transmission when handling patients & body substances.
Cephalosporin
Cephalosporium mold; widely used; over 70 forms; later generations are broad spectrum; some useful on MRSA; resistant to penicillinases, susceptible to other B-lactamases; inhibits cell wall synthesis (NAM/NAG bond)
What group of antimicrobial drugs resemble Penicillins in terms of chemical structure?
Cephalosprins
Acute infections
Characterized by rapid onset & short duration.
Human Microbiome Project
Collect genetic sequences in the gut, respiratory tract, skin, etc., to determine which microbes are there, even when they can't be grown in a laboratory. Also to determine role normal biota play in health & disease.
Alcohols
Colorless hydrocarbons with one or more-OH functional groups.
Neosporin
Combination therapy composed of Bacitracin, Neomycin, Polymyxin. Broad spectrum
Give the basis for combined therapy. Give one reason why it could be helpful to use combined therapy in treating HIV infection.
Combined therapy is used to minimize the development of resistant strains. The HIV retrovirus lacks the proofreading ability of regular DNA replication resulting in frequent mutations. These mutations can make the virus resistant to a particular drug which is why a combination of drugs is used. Multiple drugs can work synergistically so you are much less likely to get drug resistance.
TORCH
Common infections of fetus and neonate are grouped together in a unified cluster.
Contagious
Commuunicable; transmisible by direct contact with infected people & their fresh secretions or excretions.
Iodophors
Complexes of iodine & alcohol. A combination of iodine& an organic carrier that is a moderate level disinfectant & antiseptic.
Iodine compounds
Compounds that are used as a topical antiseptic and disinfectant
Chlorine compunds
Compounds that kill bacteria, endospores, fungi, and viruses.
Toxic Dose
Concentration of the drug that causes harm to the host
Cutaneous mycoses=?
Dermatophytoses
Sporadic
Description of a disease that exhibits new cases at irregular intervals in unpredictable geographic locales.
Identify advantages and disadvantages of desiccation.
Desiccated: dehydrated. What happesn to vegetative cells in room air. Many die out in normal temps but some can withstand long periods of desiccation. Desiccation can be a valuable way to preserve foods bc it greatly reduces the amount of water available to support microbial growth.
Boiling water
Destroy vegative pathogens in the homes.
Antisepsis
Destroys most microbial life, reducing contamination on inanimate surfaces
Disinfection
Destroys most microbial life, reducing contamination on inanimate surfaces
Disinfection
Destroys most microbial life, reducing contamination on inanimate surfaces.
Antisepsis
Destroys most microbial life, reducing contamination on living surfaces. Chemicals applied to body surfaces to destroy pathogens.
Incineration
Destruction of microbes by subjecting them to extremes of dry heat. Reduces microbes & other substances to ashes & gas.
Surfants
Detergents that work as microbicidal agents because they lower the surface tension of the cell membranes.
Toxinoses
Disease whose adverse effects are primarily due to production & release of toxins.
Azoles
Disrupt fungal membrane structure. Ketoconazole, Clotrimazole, Miconazole
Semisynthetic drugs
Drugs that are chemically modified in the laboratory after being isolated from natural sources.
Semisynthetic
Drugs that, after being naturally produced by bacteria, fungi, or other liiving sources, are chemically modified in the laboratory. (Designer drugs)
dry heat methods and examples
Dry heat: air with a low moisture content that has been heated by a flame or electric heating coil. 160 degrees C- several thousand degrees C. dehydrates the cell, removing water necessary for metabolic reactions. High temps over long periods of time. Proteins more stable bc of H20. Oxidizes/burns cells. Examples: oven drying
How does Tube Dilution work?
First the antimicrobial is diluted serially in tubes of broth, and then each tube is inoculated with a small uniform sample of pure culture, incubated, and examined for growth (turbidity)
Filtration
Effective method for removing microbes from air & liquids.
Ionizing
Ejects electrons, causing ions to form
Identify the types of microorganisms that are high resistant
Endospores are so high because of thick coast and in vegetative state. Heat protectant, cold protectant, Ph protectant.
Radiation
Energy emitted from atomic activities & dispersed at high velocity through matter or space. Electromagnetic waves or rays, such as those of light given off from an energy source.
List then explain the five cellular or structural mechanisms that microbes use to resist antimicrobials.
Enzymatic destruction of the drug: microbe can enzymatically split apart the antibiotic ex: penicillinase Prevention of penetration of the drug: surface receptors or channels are altered blocking drug Alteration of drug's target site: change in the microbial ribosome so antimicrobic can't bind Rapid ejection of the drug: Microbe creates a new pump with a high affinity for the drug which pumps the drug right back out Changes in metabolic patterns: the drug blocks the ususal pathway so the microbe uses an alternate pathway by slightly changing its enzymes but still getting the same metabolic outcome
Metabolic analog
Enzyme that mimics the natural substrate of an enzyme and vies for it's active site.
10. Explain the significance of beta-lactamases.
Enzymes produced by bacteria that break the lactam ring of penicillins and cephlosporins rendering the drug inactive
Drugs that affect Protein Synthesis Inhibitors Acting on Ribosomes: 50s Subunit?
Erythromycin, Clindamycin, Syncerid, Pleuromutilins
Nonionizing
Excites atoms, but does not ionize them
Nonionizing radiation
Exemplified by ultraviolet (UV), excites atoms by raising them to a higher energy state, but does not ionize them.
Desiccated
Exposing vegetative cells to normal room air causing them to gradually become dehydrated. To dry thoroughly. To preserve by drying.
T/F a higher concentration of hold as a germicide agent is more effective than a lower concentration
FALSE;silver and mercury NOT gold.
Anti-fungal drugs inhibiting NA synthesis
FLUCYTOSINE: analog of cytosine; cutaneous mycoses or in combo w/ Amphotericin-B for systemic mycoses
12. Outline the process of filtration and describe its two advantages in microbial control. Explain how filtration functions as a control method.
Filtrations: effective method ot remove microbes form air and liquids. A fluid is strained through a filter with openings large enough for the fluid to pass through but too small for microorganims to pass through. Used to prepare liquids that cannot withstand heat, inlcuind gserum and other blood products, avvines, drugs, IV fluids, enzymes, and media. Alternative method for decontaminating milk and beer without altering flavor. Water purification. Removes airborne contaminates that are a common source of infection and spoilage.
why is gram neg moderate resistance
Gram negative has moderate resistance because of cell wall. In cell wall is lipopolysaccerides. Techiolic acid.
Identify the types of microorganisms that are less resistant
Gram positive is less resistant bc it only has peptidoglycan.
What type of bacteria are penicillins effective against?
Gram(+)
Penicillin
Group of antibiotics, named for its parent compound, is a large group of compounds, most of which end in the suffix -cillin.
Sepsis
Growth of microorganisms in the blood or other tissues.
Name six methods of physical control of microorganisms.
Heat, radiation, filtration, ultrasonic waves, cold, abrupt changes in environment, drying, osmotic pressure, desiccation (dehydrate)--- number one component of cytoplasm is water so dehydration can be used.
Therapeutic Index
Highest level of the drug tolerated by the host divided by the lowest level of the drug that will eliminate the infection or pathogen; Higher Therapeutic Index is better
Identify the types of microorganisms that are most resistant
Highest resistance: prions (complex proteins and difficult to diagnosis and identify), bacterial endospores
Penicillinase
Hydrolyzes penicillin, found in penicillin-resistant strains of bacteria.
Ionizing radiation
If the radiation ejects orbital electrons from an atom, it causes ions to form. Gamma rays, X-rays, & high speen electrons are all ionizing in their effects. Works by causing breaks in the DNA of target cells.
Reservoir
In disease communication, the natural host or habitat of a pathogen.
Virulence
In infection, the relative capacity of a pathogen to invade and harm host cells.
Explain two methods of dry heat control.
Incineration: in a flame or electric heating coil 1,87 degrees C, furnaces and incinerators 800- 6500 degrees C, used for needles, beeding, tissue samples, could kill endospores. Bunsen burner is an example used for loops/needles
List major targets of antimicrobial agents
Inhibition of cell wall synthesis, nucleic acid structure and function, protein synthesis; interference with cell membrane structure and function; inhibition of metabolism
What is the most common mode of action of an antibiotic? What families of drugs perform this action?
Inhibition of cell wall synthesis. This is performed by beta-lactams and Vancomycin.
18. List the three major targets of action of antiviral drugs.
Inhibition of virus entry, inhibition of nucleic acid synthesis, and inhibition of viral assembly/release
What is the second largest class of antibiotics?
Inhibitors of protein synthesis. Can effect either the 30s or 50s subunits of the ribosome.
Synercid
Inhibits protein synthesis: effective against Staphs & Enterococci that cause endocarditis & surgical infections
Action of Antimicrobial Drugs: Inhibit DNA/RNA Synthesis
Inhibits replication and transcription
Streptomycin: what does it do?
Inserts on sites on the 30s subunit, causing misreading of mRNA **toxicity issues wrt auditory nerve**
12. Explain how drugs targeting folic acid synthesis work.
Interfere with the synthesis of folic acid, which is needed by the bacteria to make DNA/RNA, and amino acids.
Polymicrobial
Involving multiple distinct microorganisms.
Differentiate between the two types of radiation control methods
Ionizing: sterilization of medical and laboratory equipment and food preservation by use of gamma or x rays Nonionizing: disinfecting air, transparent fluids, and surfaces of objects using UV light
Bactericide
Is a chemical that destroys bacteria except fpr those in the endospore stage. It may or may not be effective on other microbial groups.
Fungicide
Is a chemical that kills fungus spores, hyphae, & yeast.
How is chemical concentration expressed?
It depends on the convention and the method of preparation. Lysol, for instance, is usually diluted 1:200, that is, one part of chemical has been added to 200 parts of water. Chlorine, which is very effective even in very diluted concentrations is expressed in parts per million (ppm). In percentage solutions, the solute is added to water by weight or volume to achieve a certain percentage in the solution. Alcohol, for instance, is used in percentages ranging from 50% to 95%.
What is an extended spectrum antibiotic?
It is a fourth generation antibiotic that functions well in the presence of beta-lactamase. This allows it to be effective against a number of (G+) and (G-) bacteria that 3rd generation antibiotics are not as good against.
What is Beta-lactamase? How is it overcome?
It is an enzyme that hydrolyzes the beta-lactam ring, stopping the action of this class of drugs. Method of bacterial defense. Overcome by pairing a penicillin with a beta-lactamase inhibitor (Augmentin is amoxicillin and clavulanic acid, etc.)
Drugs are often given to surgical patients, to dental patients with heart disease or to healthy family members exposed to contagious infections. What word would you use to describe this use of drugs? What the purpose of this treatment? Explain some undesirable effects of this therapy.
Known as antibiotic prophylaxis. It is given to prevent infection in people at risk. Undesirable effects include disruption of normal flora, allergies, toxicity
Identify the types of microorganisms that are least resistant
Least resistant: most bacterial vegetative cells, fungal spores, hyphae, enveloped viruses, yeasts, protozoan trophozoites. Gram positive bacteria
Differentiate between the four biosafety levels
Level 1- pathogens that do not cause disease Level 2-moderately hazardous agents Level 3-safety cabinets and double doors Level 4- cause severe or fatal disease
Drugs that affect Protein Synthesis Inhibitors Acting on Ribosomes: Both Subunits?
Linezolid (blocks initiation of protein synthesis)
Clotrimazole=?
Lotrimin (disrupt fungal membrane structure)
Semi-synthetic Penicillins
MACA: Methicillin, Ampicillin, Carbenicillin, Amoxicillin
What is the BIG GROUP of protein synthesis inhibitors?
MACROLIDES (ex, erythromycin)
Discuss both moist and dry heat methods, and identify multiple examples of both
MOIST more effective; boiling, autoclaving and pasteurization DRY hot air of incineration (ultimate means of sterilization);
Identify the microorganisms that are most resistant and least resistant to control measures
MOST TO LEAST RESISTANT Prions Bacterial endospores Mycobacteria Cysts of protozoa Active-stage protozoa (trophozoites) Most Gram-negative bacteria Fungi Nonenveloped viruses Most Gram-positive bacteria Enveloped viruses
16. Name the four main categories of antifungal agents.
Macrolide polyenes, Azoles, Echinocandins, and Nucleotide cytosine analog
cide (ending or root of word)
Meaning to kill
Antiprotozoan drugs
Metronidazole (Flagyl), quinicrine, sulfonamides, tetracyclines
Explain what a superinfection is and how it occurs
Microbes that were once small in number overgrown when normal resident biota are destroyed by broad-spectrum antimicrobials (ex. UTI caused by E.Coli treated with antibiotics)
Resident microbes
Microbes which normally live on our body. Each site has particular populations, and it changes over time.
moist methods of control, and identify multiple examples of each.
Moist heat: hot water, boiling water, or steam. 60 degrees C- 135 degrees C. operates at lower temperatures and shorter exposure times to achieve the same effectiveness as dry heat. Coagulation and denaturation of proteins which permanently halts cellular metabolism. Low temp and short time. Another example is steam pressure/no pressure. Pasteurization.
Miconazole=?
Monistat (disrupt fungal membrane structure)
Least resistant forms of microbes
Most bacterial vegetative cells, fungal spores, enveloped viruses, yeasts, protozoan trophozoites
Define superbug
Multidrug resistant pathogens -Staphylococcus -Mycobacterium constant use of drugs eliminates sensitive cells and stronger pathogens thrive
Fungal diseases= ?
Mycoses
Oxazolidinones
NEW CLASS of antibacterial drugs that inhibit initiation of protein synthesis. Ex: LINEZOLID which is effective against MRSA, VRE.
why are naked viruses least resistant
Naked viruses with no capsule are the least bc no protection.
13. Identify one example of a fluoroquinolone.
Nalidixic acid
Differentiate between narrow-spectrum & broad spectrum antibiotics. How does the mode of action effect the spectrum of a drug?
Narrow spectrum affect only a few types of microbes and broad spectrum affect a broad range of G+ or G- organisms. Antimicrobial drugs target certain essential function of the microbe - what they target affects whether they are narrow or broad spectrum.
What is the basic difference between a "narrow spectrum" antibiotic and a "broad spectrum"?
Narrow spectrum work against a small number of species, for example, only Gram(+). Broad spectrum work against a wide variety, i.e. both Gram(+) and Gram(-)
Distinguish between broad spectrum and narrow spectrum antimicrobials and explain the significance of the distinction
Narrow-spectrum effective against few organisms Broad-spectrum effective against many organisms; may allow for superinfections to develop; killing of normal flora
Interferin (INF)
Natural human cheemical that inhibits viral replication; used therapeutically to combat viral infections & cancer.
Prebiotics
Nutrients used to stimulate the growth of favorable biota in the intestine.
Localized infection
Occurs when a microbe enters a specific tissue, infects it, & remains confined there.
It seems like Table 9.9 is the most important thing of this chapter...
So study it before the quiz!
20. List 5 cellular or structural mechanisms that microbes use to resist antimicrobials.
New enzymes are synthesized, permeability, drug is immediately eliminated, binding sites for drugs decreased, an affected metabolic pathway is shut down
Discuss possible ways that microbes acquire antimicrobial resistance
New mutations of chromosomal genes; acquisition of R-plasmids (R-plasmid acquired by bacterial conjugation) via transformation, transduction, and conjugation (horizontal gene transfer)
Ketoconazole=?
Nizoral (disrupt fungal membrane structure)
Your pregnant neighbor has been prescribed a daily dose of oral tetracycline for acne. Do you think this therapy is advisable for her? Why or why not?
No it is not advisable. It is a broad spectrum antibiotic which can suppress the normal gastrointestinal microbiota causing diarrhea & leading to superinfections, mainly from Candida albicans (yeast infection). It can also cause liver damage in pregnant women.
How does the misuse & abuse of antibiotics encourage the emergence of resistant forms?
Not completing the full course of antibiotics results in survival of the few resistant microbes which then multiply encouraging the survival of resistant bacteria. Taking the wrong antibiotic. Continous exposure to antibiotics in the environment allow the normal flora to acquire resistance plasmids which are constantly selected for & amplified which then "jump" to humans & share the plasmids that carry the resistance gene.
Endogenous
Originating or produced within an organism or one of its parts.
Exogenous
Originating outside the body.
Explain how filtration and osmotic pressure function as control methods
Osmotic Pressure: high concentrations of salt solutes or sugar in foods inhibit growth and metabolism; lose water Filtration: sterilize; uses membrane filter to trap microbes
Identify some common uses of osmotic pressure as a control method.
Osmotic pressure: preserving food. Adding large amounts of salt or sugar to foods creates a hypertonic environment for bacteria in the foods, causing plamoylsis and making it impossible for bacteria to multiple. Meats are cured. High surag concentration in foods like jelly.
Name methods of physical control of microorganisms
PHYSICAL Heat-related methods Refrigeration and Freezing Desiccation and Lyophilization Filtration Osmotic Pressure Radiation Biosafety Levels CHEMICAL Oxidizing agents Aldehydes Gaseous agents Enzymes
Exoenzymes
Pathogenic bacteria, fungi, protozoa, & worms secretion that breaks doown & inflicts damage on tissues.
Gastrointestinal tract
Pathogens that enter here are contained in food, drink, and other ingested substances. They are adapted to survive digestive enzymes and pH changes.
Skin
Pathogens that enter here enter through nicks, cuts, and punctures. Some create their own passageways using digestive enzymes or insect bites.
Urogenital system
Pathogens that enter here enter through the skin or mucosa of penis, external genitalia, vagina, cervix, and urethra. Some can penetrate an unbroken surface.
What is penicillinase? What effect does penicillinase have on beta-lactam antibiotics? How do bacteria acquire penicillinase? What effect does penicillinase have on eukaryotic cells?
Penicillinase is an enzyme secreted by many bacteria that cleave the b-lactam ring in b-lactam antibiotics. Bacteria can acquire penicillinase through conjugation, transformation, or transduction. It has not effect on eukaryotic cells because penicillin targets the peptidoglycan in cell walls (and penicillinase cleaves penicillin).
The drug with the best selective toxicity because it is low toxicity and few direct effects on human cells because we lack the chemical peptidoglycan, and are thus unaffected by this action of the antibiotic
Penicillins
Drugs that are Cell Wall Inhibitors
Penicillins Cephalosporins Carbapenems Polypeptide Antibiotics (Bacitracin, Vancomycin) Antimycobacterial Antibiotics (Isoniazid, Ethambutol)
Determine the selective toxicity for each class of drug discussed in class based on their mode of action.
Penicillins - High Selective Toxicity - High Therapeutic Index Vancomycin - Low therapeutic index (unsafe) Penicillin plus B-lactamase inhibitor - High Therapeutic Index Carbapenems - High Selective Toxicity Cephalosporins - High Therepeutic Index Bacitracin - Safe if topical; Low therapeutic index taken orally Antimycobacterial Antibiotics - High Selective Toxicity Polyenes (Antifungals) - Intermediate Toxicity Aminoglycosides - Low therapeutic index (unsafe) Tetracyclines - High Selective Toxicity Macrolides - High Selective Toxicity Chloramphenicol - Very Low therapeutic index (unsafe) Sulfa Drugs - High Selective Toxicity Antiviral - High Selective Toxicity - difficult to maintain
Drugs that affect Cell Wall Inhibitors?
Penicillins, Cephalosporins, Carbapenems, Vancomycin, Fosfomycin, Isoniazid
Examples of drugs that target the cell wall
Penicillins, cephalosporins, bacitracin, isoniazid, vancomycin
Penicillin: origin
Penicillium chrysogenum. Originally narrow spectrum and bactericidal against Gram +
Passive carrier
Persons who mechanically transfer a pathogen without ever being infected by it. For example, a health care worker who does not wash his hands adequately between patients.
Resistance-Factor (R-Factor)
Plasmids, typically shared among bacteria by conjugation, that provide resistance to the effects of antibiotics
Resistance (R) factors
Plasmids, typically shared among bacteria by conjugation, that provide resistance to the effects of antibiotics.
Table 9.8: Required Concentrations and Times for Chemical Destruction of Selected Microbes.
Refer to page 249 if you need to know this stuff.
What are the general mechanisms of defense against antibiotics?
Prevents of access to the target (i.e. thicker cell wall, resistant outer pores) Inactivation of the antibiotic (beta-lactamase or ESBL - extended spectrum beta lactamase) and Alteration of target (modified PBPs or a modified peptidoglycan target).
Adhesion
Process which microbe gain a more stable foothold at portal of entry.
Proteins
Proteins function relates to their shape. All proteins react at their shape. If you change the shape of the protein then you change the function. You can add an agent also that will block active site that will compete for active sight of the substrate. The agent could be a drug. The blocking is called competitive inhibitions.
Moderate resistant forms of microbes
Protozoan cysts, fungal sexual spores, naked viruses, resistant vegetative bacteria
Explain why antiprotozoal and antihelminthic drugs are likely to be more toxic than antibacterial drugs
Protozoas and Helminths are in the Eukaryote domain and therefore share similar features to humasn, thus more damage to the human cells would occur
Inhibitors of nucleic acid synthesis:
QMR: Quinolones, Metronidazole, Rifamycin
Antimalarial drugs
Quinine, Chloroquine, Primaquine
Rifamycin: Inhibitor of NA synthesis
RIFAMPIN: inhibits RNA polymerase/transcription. Ideal treatment: Mycobacterium (Leprosy, TB)
Ultraviolet (UV) radiation
Ranges in wavelength form 100nm to 400 nm. It is most lethal from 240nm to 280 nm. Object must be directly exposed for full effect. Germicidal lamp used which generates radiation of 254 nm. Induces mutations but has very poor penetrating power.
Convalescent period
Recovery; the period between the end of the disease & the complete restoration of health in a patient.
State the main goal of antimicrobial treatment
Reduce the incidence of certain infections
Degermation
Reduce the numbers of microbes on the skin. Involves scrubbing the skin or immersing it in chemicals, or both.
Figure 9.7: Modes of Affecting Protein Function
Refer to page 252. *Figure a.* Native state maintained by bonds that create active sites to fit the substrate. Some agents denature the protein by breaking all or some secondary and tertiary bonds. Results are *b.* complete unfolding or *c.* random bonding and incorrect folding. *d.* Some agents react with functional groups on the active site and interfere with bonding.
Table 9.10: Active Ingredients of Various Commercial Antimicrobial Products.
Refer to page 253 if you need this information.
Table 9.9: Germicidal Categories According to Chemical Group.
Refer to pages 250-251 if you need to know this information in detail. Chemicals that target spores include... *Chlorine* (liquid/gaseous): Kills spores slowly and all other micorbes; works by combining with water and releasing hypochlorous acid which denatures enzymes and permanently suspends metabolic reactions. *Iodine*: Kills spores slowly and all other microbes; works by penetrating cells and interfering with a variety of metabolic functions as well as the hydrogen and disulfide bonding of proteins. *Hydrogen peroxide*: Kills spores and all other microbes; works by oxygen forming free radicals that are highly toxic and reactive to cells. *Aldehydes*: Kills spores and all other microbes; Glutaraldehyde disrupts the activity of enzymes and other proteins within the cell, and Formaldehyde is an irritating gas that dissolves in water to form an aqueous solution called formalin, which attaches to nucleic acids and functional groups of amino acids. *Ethylene oxide* (gaseous): Kills spores; works by reacting wtih functional groups of DNA and proteins, blocking both DNA replication and enzymatic actions.
Microbial antagonism
Relationship in which micrroorganisms compete for survival in a comon environment by taking actions that inhibit or destroy another organism.
Folic acid pathway
Repressible metabolic pathway of which the product is Tetrahydrofolic acid, a coenzyme required to synth purines, pyrimidines, aa's.
Resistance Factors
Resistance occurring through horizontal transfer from plasmids
Thermoduric
Resistant to the harmful effects of high temperature. Examples: Nonpathogenic lactobacilli, micrococci, & yeast
Pyrimidine dimers
Site where specific molecular damage occurs when UV radiation passes through a cell. The union of two adjacent pyrimidines on the same DNA strand, brought about by exposure to ultraviolet light. It is a form of mutation.
Examples of drugs that affect nucleic acid synthesis
Rifampin, nalidixic acid, fluouroquinolones, ciprofloxacin
Inhibitors of NA synthesis: 2 groups
Rifamycins & Quinolones
Doxycycline + Minocycline: common treatments for....
Rocky Mountain spotted fever, Lyme disease, typhus, acne, protozoan infection
Portal of entry
Route of entry for an infectious agent; typically a cutaneous or membranous route.
Portal of exit
Route through whcih a pathogen departs from the host organism.
What is the problem with treating viral infections?
Selective toxicity is almost impossible to achieve because a single metabolic system is responsible for the well-being of both virus and host
Selecting a Microbicidal Chemical
Some desirable qualities that you want in your chosen germicide: - Rapid action even in low concentrations. - Solubility in water or alcohol and long-term stability. - Broad-spectrum microbicidal action without being toxic to human and animal tissues. - Penetration of inanimate surfaces to sustain a cumulative or persistent action. - Resistance to becoming inactivated by organic matter. - Noncorrosive or nonstaining properties. - Sanitizing and deodorizing properties. - Affordability and ready availability. As of yet, no chemical can fulfill all of these requirements, but glutaral dehyde and hydrogen peroxide approach this ideal.
Define-static. Compare the action of microbicidal and microbistatic agents, providing an example of each.
Statis/Static: to stand still. To denote a condition in which microbes are temporarily prevented from multiplying but are not killed outright. Microbistatic: control micoorganisms in the body (antiseptic and drugs) look up examples.
Cold sterilization
Sterilizes in the absence of heat. Used for materials that are sensitive to heat or chemicals. Examples: radiation of filtration
Ergosterol
Sterol in the membrane of a fungus
1st TB antibiotic?
Streptomycin (Streptomyces sp.) inserts on sites on 30s subunit, causing misreading of mRNA (toxicity issues wrt auditory nerve)
11. Identify two antimicrobials that act by inhibiting protein synthesis.
Streptomycin, Tigecycline
Gnotobiotic
Studies in whch a germ free subject is inoculated either with a single type of microbe to determine its individual effect or with several microbes to determine interrelationships.
Antibiotics
Substances produced by the natural metabolic processes of some microorganisms that can inhibit or destroy other microorganisms.
Explain how drugs targeting folic acid synthesis works
Sulfonamide inhibits folic acid synthesis that is required for nucleotides in bacteria and protozoans; inhibit the biosynthetic pathway that leads to the formation of DNA & RNA
Examples of drugs that affect folic acid synthesis
Sulfonamides and trimethoprim
Action of Antimicrobial Drugs: Inhibit Synthesis of Folic Acid
Sulfonamides compete with the substrate PABA for the active site on the enzyme. PABA is the substrate for the enzymatic reaction leading to sythesis of folic acid, a vitamin that functions as a coenzyme for synthesis of nucleic acid bases & many amino acids
What does it mean if a bacteria is "Susceptible" to an antibiotic? "Intermediate"? "Resistant"?
Susceptible means that bacteria are inhibited by achievable concentrations of antibiotic, while intermediate means response rates vary depending on the pharmacokinetics. If they can be used at higher than normal dosage, can be effective (beta-lactams). Resistant means that bacteria is unlikely to be effected by achievable concentrations.`
Aerosols
Suspensions of fine dust or moisture particles in the air that contain live pathogens.
Fluoroquinolones
Synthetic antimicrobial drugs chemically related to quinine. They are broad spectrum & easily absorbed from the intestine.
Doxycycline
Synthetic tetracycline; longer retention in body; used to be added to animal feed
Septicemia
Systemic infection associated with microorganisms multiplying in circulating blood.
Effective antiviral drugs do what?
Target viral replication by preventing entry, inhibiting nucleic acid synthesis, inhibiting viral protein function, & targeting viral assembly & release. They protect uninfected cells.
Pasteurization
Technique in which heat is applied to liquids to kill potential agents of infection & spoilage, while at the same time retaining the liquids flavor & food value.
Tyndallization
Technique requires a chamber to hold the materials & a reservoir for boiling water. Items in the chamber are exposed to free-flowing steam for 30 to 60 minutes. (Vegetative cells are destroyed by repeated steaming & incubation.)
Communicable
The ability of a disease causing organism to be spread between individuals
Edema
The accumulation of excess fluid in cells, tissues, or serous cavities. Also called swelling.
Interferons
The body's natural defense against viruses
Pathogenicity
The capacity of microbes to cause a disease or infection.
Syndrome
The collection of signs & symptoms that, taken together, paint a portrait of the disease.
Infection
The colonization of an organism by a microorganism, with or without disease
Therapeutic Dose
The concentration of the drug that effectively destroys or eliminates the pathogen from the host
Virulence
The degree of ability in a microbe to cause disease in another organism
Sterilization
The destruction of all microbial life
disinfection
The destruction or removal of vegetative pathogens but not bacterial endospores. Usually used only on inanimate objects. Example UV light, boiling water, chemicals
Droplet Nuclei
The dried residue of fine droplets produced by mucus & saliva sprayed while sneezing & coughing.
What is another factor that contributes to germicidal effectiveness?
The length of exposure! Most compounds require adequate contact time to allow the chemical to penetrate and to act on the microbes present. The composition of the material being treated must also be considered. Smooth, solid objects are more reliably disinfected than are those with pores or pockets that can trap soil. An item contaiminated with common biological matter such as serum, blood, saliva, pus, fecal material, or urine presents a problem in disinfection. Large amounts of organic material can hinder the penetration of a disinfectant and, in some cases, can form bonds that reduce its activity.
Thermal death point
The lowest temperature required to kill all microbes at a specified temperature
Thermal Death point- TDP
The lowest temperature required to kill all microbes in a sample in ten minutes.
Decontamination
The mechanical removal of most microbes from an animate or inanimate surface
Etiologic (agent)
The microbial cause of disease; the pathogen.
Normal (resident) biota
The native microbial forms that an individual harbors.
Morbidity rate
The number of person inflicted with an illness under question or with illness in general, expressed as a numerator, with the denominator being some subunit of population (as in x/100,000).
Mortality rate
The number of persons who have died as the result of a particular cause or due to all causes, expressed as a numerator, with the denominator being some subunit of population (as in x/100,000).
Period of invasion
The period during a clinical infection when he infectious agent multiplies at high levels, exhibits its greatest toxicity, & becomes well established in the target tissues.
Incubation period
The period from the initial contact with an infectious agent to the apperance of the first symptoms.
Source
The person or item from which an infection is directly acquired.
Bacteremia
The presence of viable bacteria in the circulating blood.
Viremia
The presence of viruses in the bloodstream.
Competitive Inhibition
The process of a substance reducing the activity of an enzyme by entering the active site in place of the substrate whose structure it mimics.
What is empirical therapy?
Therapy that begins before the etiologic agent can be identified. Based on most likely pathogen and drug most likely to be effective.
Define therapeutic index and identify whether a high or low index is preferable
The ratio of the dose of the drug that is toxic to humans as compared to its minimum effective (therapeutic) dose; toxic dose-MIC (min. inhibitory concentration); the smaller the ratio, the greater the potential for drug reactions; the drug with the highest (larger) therapeutic index has the widest margin of safety
4. Define therapeutic index, and identify whether a high or a low index is preferable.
The ratio of the dose of the drug that is toxic to humans as compared to its minimum effective dose. The smaller the ratio the safer the drug.
Therapeutic index (TI)
The ratio of the toxic dose to the effective therapeutic dose that is used to assess the safety and reliability of the drug.
Thermal death time
The shortest length of time required to kill all test microbes at a specific temperature
Thermal Death time- TDT
The shortest length of time required to kill all test microbes at a specified temperature.
Minimum inhibitory concentration MIC
The smallest concentration of drug needed to visibly control microbial growth.
Latency
The state of being inactive. Example: a latent virus or latent infection.
Infectious disease
The state of damage or toxicity in the body caused by an infectious agent.
Epidemiology
The study factors affecting the prevalence & spread of disease within a community.
Metagenomics
The study of all the genomes in a particular ecological niche, as opposed to individual genomes from single species.
Symptom
The subjective evidence of infection & disease as percieved by the patient.
Toxigenicity
The tendency of a pathogen to produce toxins. Power to produce toxins.
Synthetic Drugs
The use of chemical reacionsto synthesize antimicrobial compounds in the laboratory.
Antimicrobial Chemotherapy
The use of chemotherapeutic drugs to control infrection.
What is the problem with treating fungal infections?
Their cells are eukaryotic, so they are similar to human cells.
Drugs that affect Folic Acid Synthesis in the Cytoplasm?
These block the pathways and inhibit metabolism: Sulfonamides (sulfa drugs), Trimethoprim
Tetracycline antibiotics
These drugs are broad spectrum, and cause GI problems in some people. Used on gram positive and gram negative rods and cocci, aerobic and anaerobic bacteria, mycoplasmas, rickettsias, and spirochetes
How drugs disrupt cell membrane function
These drugs are microbe-specific based on the type of LIPIDS in their cell membranes.
Trimethoprim
These drugs are one of the primary treatments for pneumonia in AIDS patients
Aminoglycoside drugs
These drugs are relatively broad spectrum because they inhibit protein synthesis
How do drugs affect cell membranes?
These drugs bind phospholipid and lipid A, thus disrupting the membranes. This results in death from disruption in metabolism, and is based on the differences in the types of lipids in their cell membranes.
Penicillins
These drugs block cross-linking of peptidoglycan (cell wall). They have a beta-lactam ring.
How do drugs affect nucleic acid synthesis?
These drugs block synthesis of nucleotides, inhibit replication, stop transcription, and inhibit DNA synthesis.
Cephalosporins
These drugs have a different ring structure, but they also block cross-linking of peptidoglycan (cell wall) and have a beta-lactam ring. They are broad spectrum, resistant to most penicillinases, and cause fewer allergic reactions than penicillins.
How do drugs affect protein synthesis?
These drugs inhibit translation by reacting with the ribosome mRNA complex
How do drugs affect folic acid synthesis?
These drugs use competitive inhibition to prevent the synthesis of folic acid. It is supplied to cells in high concentrations to make sure the enzyme is constantly occupied with the metabolic analog rather than the true substrate
Sulfonamides
These drugs were the very first modern antimicrobial drug. They are synthetic (inhibit folic acid production)
Opportunists
These microbes cause disease when given the opportunity. They enter the body by breakdown in immunity, certain medical treatments, and implantation of devices.
Transient microbes
These microbes do not normally reside, just passing through. Most are harmless, but some are pathogens.
Pathogens that infect during pregnancy and birth
These pathogens can cross the placenta, and some infections can occur when the child is contaminated by the birth canal
How do anti-metabolites function?
They compete with p-aminobenzoic acid, inhibiting modification of PABA into dihydrofolate.
Do sulfonamide drugs have a high or low selective toxicity for humans? Why?
They have a low selective toxicity for humans because they inhibit the synthesis of folic acid. Humans don't synthesize folic acid, its ingested in their diet.
17. Explain why antiprotozoal and antihelminthic drugs are likely to be more toxic than antibacterial drugs.
They have greater similarities to humans, which make them harder to treat.
What is the general mechanism of antibiotics that affect the cytoplasmic membrane?
They interact with the phospholipids and increase the cell permeability, resulting in apoptosis. Can be stopped by inability to reach inner membrane (via outer or thick peptidoglycan)
Degree of Pathogenicity
This is determined by the microbe's ability to establish itself in the host and cause damage
Respiratory tract
This is the portal of entry for the greatest number of pathogens.
Reportable diseases
Those diseases that must be reported to health authorities by law.
Statis and static
To stand still; prevent multiplication
There is an inverse relationship between what two elements of an antibiotic?
Toxicity and effectiveness. Typically, natural antibiotics are more toxic, while synthetic are more effective.
Most sensitive and quantitative results can be obtained with
Tube Dilution Tests.
Tamiflu
Type of Oseltamivir, drug that targets release stage of viral infection
Relenza
Type of Zanamivir, drug that targets release stage of viral infection
Prophylaxis
Use of a drug to preventb imminent infection of a person at risk.
Antiphagocytic factors
Used by some pathogens to avoid phagocytes
Therapeutic index
Used to figure out what is the best drug to use; lowest risk of side effects vs. highest probability of killing the pathogen. The higher, the better
Cold
Used to slow the growth of cultures and microbes in food during processing and storage.
Autoclaves
Utilize steam under pressure to sterilize heat-resistant materials.
important about viruses
VIRUSES ARE NOT LIVING OR DEAD. THEY ARE ACTIVE OR INACTIVE
Why do humans experience negative side effects from drugs that inhibit protein synthesis?
We have bacteria in our cells too!!! Consider: mitochondria!
Antiviral - Protease Inhibitors
When a new virus is made it begins by cutting up large proteins with protease enzymes. The fragments are then used to assemble new viruses. Analogs of amino acid sequences (structurally similar) can serve as inhibitors by interfering with their activity (protease inhibitors). Saquinavir is a brand of protease inhibitor.
23. Explain what a super infection is and how it occurs.
When therapy destroys beneficial resident species, other microbes that were once in small numbers begin to overgrow and cause disease.
Microbial death
When various cell structures become dysfunctional and the entire cell sustains irreversible damage
Phagocytes
White blood cells that engulf and destroy pathogens
Hemolyze
Wred blood cellss burst & release hemoglobin pigment.
Parenteral
administering drugs via IV
Drug Resistance
an adaptive response in which microorganisms begin to tolerate an amount of drug that would ordinarily be inhibitory
The Kirby-Bauer Technique is?
an agar diffusion test that provides useful data on antimicrobial susceptibility. The surface of a plate of special medium is spread with the test bacterium, and small discs containing premeasured amount of antimicrobial are dispensed on the bacterial lawn.
E-Test
an alternative diffusion system that provides additional information on drug effectiveness (other test is the Kirby Bauer)
portal of exit
an avenue of departure for pathogens to exit
Penicillinases
an enzyme that cleaves the b-lactam ring in penicillin molecule; a type of b-lactamase
carrier
an individual who inconspicuously shelters a pathogen and spreads it to others without any notice
Superinfection
an infection occurring during antimicrobial therapy that is caused by an overgrowth of drug-resistant microorganisms
endemic
an infectious disease that exhibits a relatively steady frequency over a long time periof in a particular geographic locale
What is the Kirby-Bauer Technique less effective for?
anaerobic, fastidious, or slow-growing bacteria.
Identify applications for ethylene oxide sterilization
artificial heart valves, catheters, syringes, and other items that are sensitive to heat and water soluble chemical
steam under pressure
autoclave. Pressure cooker. 121 degrees C and 15 psi. surgical equipment.
zone of inhibition
bacteria free circles of varying sizes around some disks in the Kirby Bauer test - indicate the organism is suseptible to antimicrobial; measure the diameter in MM can compare to the chart
Many antimicrobials are derived from
bacteria in the genera Streptomyces and Bacillus. and molds in the genera Penicillium and Cephalosporium.
Why does the penicillin group of drugs have milder toxicity than many other antibiotics?
because penicillins affect cell wall synthesis and eukaryotic cells do not have cell walls therefore lower toxicity
The drug that is most toxic to humans are drugs that act upon which structure?
cell membrane
what are the main cell targets for antimicrobials?
cell wall cell membrane cellular synthesis processes (DNA, RNA) proteins
Clavulanic acid
chemical added to some penicillin's to inhibit
Carbapenems
class of B-lactam antibiotics; substitutes a C atom for a S atom & adds a double bond to the penicillin nucleus; broad activity; effective against 98% of bacteria in hospital patients
Selection of a proper antimicrobial agent begins by?
demonstrating the "in vitro" activity of several drugs against the infectious agent by means of standardized methods. In general, these tests involve exposing a pure culture of the bacterium to several different drugs and observing the effects of the drugs on growth.
dry heat
denatures proteins and burns cells.
What is the main goal of antimicrobial therapy?
destroy the infectious agent and do no harm to the host
What is the MIC or Minimum Inhibitory Concentration useful for?
determining the smallest effective dosage (highest of a drug and in providing a comparative index against other antimicrobials
Semisynthetic Penicillin
developed to overcome disadvantages of natural penicillin. Keeps the antibiotic nucleus & adds functional groups in the lab
Explain the applications of hydrogen peroxide agents
disinfect and sterilize; high-level germicide
noncommunicable disease
does not arise through transmission of the infectious agent from host to host
Antiviral
drug that inhibits viral infections
Selective toxicity
drugs kill or inhibit microbial cells without harming the host
Synthetic Drugs
drugs produced entirely by chemical reactions
semisynthetic drugs
drugs that are chemically altered in a laboratory after being isolated from natural sources
Semisynthetic Drugs
drugs that are chemically modified in the laboratory after being isolated from natural sources
The goal of antimicrobial drugs is to
either disrupt the cell processes or structures of bacteria, fungi, and protozoa or to inhibit virus replication.
Dry oven
electric or gas that has coils that radiate heat within an enclosed compartment. 160 degrees C. large mass sterilizations. Kitchen oven. Dry heat denatures proteins and burns cells.
Beta-lactamase
enzymes produced by bacteria that break the lactam ring of penicillins and cephlosporins rendering the drug inactive
beta-lactamases
enzymes that cleave the beta-lactam ring, and thereby render penicillins and other beta-lactam antibiotics inactive
nonionizing radiation
exemliefied by ultraviolet, excites atoms by raising them to a higher energy state, but it does not ionize them. Leads to the formation of abnormal bonds within molecules such as DNA and is source of mutations. Excites atoms, raising them to higher energy state. Leads to the formation of abnormal bonds (pyrimidine dimers) within molecules such as DNA (T-T or C-C)
universal precautions
guidelines from the Centers for Disease Control and Prevention. they assume that all patient speciments could harbor infectious agents, and they require body substance isolation techniques to be used in known cases of infection
What are some things that a doctor must investigate before prescribing a specific antimicrobial?
history of the patient to discover any preexisting medical conditions that will influence the activity of the drug or the response of the patient, allergy to a certain class of drugs , underlying liver or kidney disease, the intake of other drugs must be carefully observed and noted to avoid any interactions or toxicities, infants elderly and pregnant women require special precautions, genetic or metabolic abnormalities, site of infection and route of administration, and also cost.
ionzing radiation
if the radiation ejects orbital electrons from an atom, it causes ions to form (gamma rays, x rays, high-speed electrons). Radiation ejects orbital electrons from an atom, causing ions to form. Causes the most damage to proteins. COLD sterilization is used for materials sensitive to heat or chemicals. Breaks DNA.
Antihelminthic drugs
immobilize, disintegrate, or inhibit metabolism: MEBENDAZOLE- broad-spectrum.
Incineration
in a flame or electric heating coil 1,87 degrees C, furnaces
nosocomial infections
infectious diseases that are acquired or develop during a hospital stay
Mebendazole
inhibit microtubules action, glucose utilization; disables helminths (broad-spectrum/fungistatic)
Aminoglycosides (Streptomycin & Neomycin (topical))
inhibit protein synthesis by changing the shape of the 30S portion of the ribosome; derived from Streptomyces & Micromonospora; broad spectrum; used to treat bubonic plague & STDs; toxic side effects include auditory nerve damage & kidney damage
Most of the antimicrobial drugs used in chemotherapy do what?
interfere with the function of the enzymes required to synthesize or assemble macromolecules, or they destroy structures already formed in the cell.
Tetracyclines
interferes with the attachment of tRNA to mRNA ribosome complex; broad spectrum & low cost; penetrates tissues well, intracellular rickettsias & chlamydias, UTIs, STDs
Bunsen burner
is an example used for loops/needles
Why is the "perfect antimicrobial drug" so hard to achieve?
it needs to be easy to administer, yet able to reach the infectious agent anywhere in the body; also be absolutely toxic to the infectious agent, while being nontoxic to the host; and remain active in the body as long as needed, yet safely and easily broken down and excreted. additionally, microbes in biofilms often require different drugs than when they are not in biofilms
Protein and nucleic acid synthesis
it would inhibit transcription. Any enzyme that go along with transcription such as enzymes like RNA polymerase. What would happen if you had a drug that inhibited heliocase activity it would hurt DNA replication and transcription (RNA polymerase). Something that inhibits the ribosome would be mRNA and rRNA (those 2 make up the ribosome, and tRNA. If you impacted cellular respiration... step for cellular respiration is glycolsis, you then have krebs cycle (goes around twice), then you would have electron transport chain. All 3 are aerobic.
Explain the mechanism of Acyclovir
its a synthetic nucleotide analog (structurally similar) that targets DNA replication, blocking DNA synthesis
antispesis is a disinfected on ____ surfaces
living
What is preferred, a high or low minimum inhibitory concentration?
low, you want this low and the toxic dose high.
Action of Antimicrobial Drugs: Inhibiting Cell Wall Synthesis
prevent the cross-linking of NAM subunits in the peptidoglycan which weakens te cell walls leading to lysis. Beta -lactam rings bind to the enzymes that cross link the subunits (Penicillins,Cephalosporin, Carbapenems, Bacitracin, Vancomycin)
Identify the types of microorganisms that are moderate resistant
protozoan cysts, gram negative bacteria, some fungal sexual spores, some viruses, naked viruses with capsule are more than enveloped forms (hepatitis B virus, poliovirus.) Bacteria with more vegetative cells mycobacterium tuberculosis, staphylococcus aureus, pseudomonas
spectrum of microbial activity
range of distinctly different types of microorganisms affected by an antimicrobial drug; can be broad or narrow
Antimicrobial Resistance
relative or complete lack of effect of an antimicrobial agent against a previously sensitive microbe
adequate sterilzation
requires that both temp and length of exposure be condisered. Highter temp allow shorter exposure times and lower temp require longer exposure time.
sterilization
the complete removal or destruction of all viable microorganisms. Used on inanimate objects. Example xray, dry oven, steam under pressure.
index case
the first patient found in an epidemiological investigation
source
the individual or object fom which an infection is actually acquired
decontamination
the mechanical removal of most microbes from animate or inaminate surface. Example Filtration
reservoir
the primary habitat in the natural world from which a pathogen originates
Antibiogram
the profile of antimicrobial sensitivity. Provides data for drug selection
Therapeutic Index (TI)
the ratio of the dose of the drug that is toxic to humans as compared to its minimum effect (therapeutic) dose. The closer the two figures are (the smaller the ratio), the greater is the potential for toxic drug reactions.
Minimum Inhibitory Concentration (MIC)
the smallest concentration (highest dilution) of drug that visibly inhibits growth
epidemiology
the study of the frequency and distribution of disease and other health related factors in defined populations
synthetic drugs
the use of chemical interactions to synthesize antimicrobial compounds in the laboratory
Antimicrobial Chemotherapy
the use of chemotherapeutic drugs to control infection
antimicrobial chemotherapy
the use of chemotherapeutic drugs to control infection
extracellular enzymes
these break down and inflict damage on tissues or dissolve the host's defense barriers
Selective Toxicity
they should kill or inhibit microbial cells without simultaneously damaging host tissues. this is central to antibiotic treatment, and the best drugs are those that block the actions or synthesis of molecules in microorganisms but not in the vertebrate cells.
Gyrase
unwinding enzyme in DNA/RNA
Prophylaxis
use of a drug to prevent imminent infection of a person at risk
prophylaxis
use of a drug to prevent imminent infection of a person at risk
bioterrorism
use of microorganisms or toxins from living organisms to cause death or disease in humans, livestock, or plants
agroterrorism
use of microorganisms to decimate the agricultural industry
Probiotics
uses live microorganisms to replace or augment the normal flora
Systemic mycoses
usually caused by soil fungi; cause special problems in immunocompromised hosts, e.g. pneumocystis pneumonia, Valley fever.
Antimycobacterial antibiotics
very specific; used against Mycobacterium tuberculosis (isoniazid inhibit synthesis of mycolic acids / ethambutol inhibits the incorporation of mycolic acid into cell wall
communicable disease
when an infected host can transmit the infectious agent to another host and establish infection in that host
Penicillinase aka
ß-lactamase: Penicillin -> Penicilloic acid
