Microbiology Exam 2 witherite

What is required for viruses to reproduce? This makes them what type of parasite?

Capsid and DNA or RNA. This makes them obligate intracellular parasites.

What is the shell of a virus called and what is it made of? What are the individual subunits called? What shapes can it take on?

Capsid: made of capsomeres that are made of protein molecules. They can take on shapes such as... 1. Helical capsid: cylinder 2. Icosahedral: round shape with corners 3. Complex: asymmetrical shape

what components must all media have?

Carbon (needed to grow) Nitrogen (needed to grow) pH buffer (keeps environment relatively neutral)

What circumstances can make an antimicrobial action?

Cell wall, cell membrane, cellular synthesis, proteins

What is an essential nutrient? What is the difference between macronutrients and micronutrients? What is the difference between organic and inorganic nutrients? What are the six elements that make up most of the organic molecules in microbes?

Chemicals that are necessary for particular organisms to function but are unable to produce themselves are essential nutrients. Carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur Macro is consistent across all living things and play a role in cell structure and metabolism Micros are trace elements are found in smaller amounts and are used for enzyme function and maintenance of protein structure. organic: nutrients are carbon or hydrogen based inorganic: nutrients are everything else

Which group encompasses most of the microbes that we will study?

Chemoheterotrophs

Types of antimicrobial drugs: what is the difference between antibiotics, synthetic, and semisynthetic agents? Selective toxicity, kills the invader, not the host. What is the difference between broad spectrum and narrow spectrum antibiotics?

Chemotherapeutic drugs: chemical used to cure disease Broad spectrum drug: effective against wide variety of microbes Narrow spectrum drug: effective against targeted disease Antimicrobial drug: given for infectious disease 1. antibiotic: produced by microorganism to kill another 2. semi-synthetic drug: alter antibiotic in lab 3. synthetic drug: made in the lab

How is osmotic pressure used in microbial control?

Create hypertonic environment with salt or sugar. It is used for preservation but does not sterilize.

What are cytopathic effects? Describe some examples of CPE's following viral infection.

Cytopathic effects: virus induced damage to the cell that changes its microscope appearance. (EX: inclusion bodies: damaged organelles or extra parts) Synctia: cells formed together to form nucleic mass

What is always inside the shell of a virus? What is sometimes inside?

DNA or RNA are always inside but sometimes there can be enzymes

What are prophylactic antibiotics? When are they given? Why do most medical professionals avoid this unless absolutely necessary?

Given before you are sick. But medical professionals avoid this because it can increase the bacteria's resistance to the antibiotic.

What is a colony?

Group of microbes growing together

What is meant by microbial growth? In relation to this, what is generation time? What is typical for generation time of bacteria?

Growth is # not in size. Generation time is time between birth and reproduction. Typical generation time for bacteria is 30-60 minutes.

What is host range? What are tropisms? What property of a host cell helps determine whether is is within the range?

Host range: which organism, virus can affect. Tropisms: what tissue virus will latch onto. Whether or not the cell has receptors determines if the virus can latch onto the cell or not.

What is a superinfection? How can it be treated/managed?

Infections occurring after or on top of another infection, especially following treatment. Treated with: probiotics, probiotics, transplant

What are the three main mechanisms of antiviral drugs?

Inhibit virus entry, inhibit nucleic acid synthesis, inhibit assembly and release

Which common human pathogen is a facultative halophile?

staphylococcus aureus??

what is inoculation? what is media? what do we call the tiny amount of sample used to start a culture?

Inoculation: introducing inoculum to correct media Media: the substance you grow the sample on Tiny sample used to start culture: inoculum

What are some concerns in choosing a method of microbial control?

substance being treated, cost, effectiveness, and disposal

What is the goal of antimicrobic therapy?

to kill microbes without harming the host

What are some possible ways to inspect and identify microbes>

using a microscope, biochemical tests, genetic and immunologic characteristics.

How does radiation damage microbes? What are the types of radiation used for microbial control? What level of control is achieved by each? What are the benefits, uses, and drawbacks of each?

Radiation interfere with microbe DNA Ionizing: uses Gamma and X-rays. Kill all microbes, but gets everywhere because it can penetrate anything. Can alt human DNA. Nonionizing: UV rays, disinfects, penetrates only air and some liquids, used for surgery rooms, but can also mutate human DNA

What makes an ideal microbicidal chemical?

Rapid acting even at low concentrations, soluble and stable in water or alcohol, broad spectrum but not harmful to human cells, penetrative to surfaces for long times, resistant to interference of organic material, non corrosive and non staining, sanitizing and deodorizing, affordable and available

What are reducing, carbohydrate fermentation, assay, transport and enumeration media?

Reducing media: 02 free Carbohydrate fermentation: different sugars Assay media: test media for different stressors on microbes (antibiotic testing) Transport media: used to transport sample Enumeration: used to count microbes

What effects do viruses have on human health worldwide?

Regional viruses affect certain parts of the world, could be: simple acute infections, high mortality, long term disability. Impossible to come up with exact #. Possible connections to chronic affiliations (Alzheimer's)

What supports for growth can an incubator provide?

Right temperature & gas

What are selective and differential media? Why are they used?

Selective media: selects microbes to grow, inhibits others. Differential media: everything grows but looks different

What are some of the factors that make an antimicrobial drug ideal?

Selective toxicity, kills the invader, not the host

What are sepsis and antisepsis?

Sepsis: growth in blood or other tissues Antispesis: prevent contamination of tissues

What are some methods of measuring bacterial growth?

Turbidity: cloudier the higher population Coulter Count: using lasers to count Flow Cytometry: uses lasers but tells if alive or dead

What are some factors that affect the activity of chemical agents?

Type of microorganisms, type of material being treated, degree of contamination, time, strength of germicide.

How does filtration achieve sterility? Why would sterile filtration be used as opposed to other methods of microbial control? What are some limitation of filtration?

Used to filter air or liquid, does not alter substances with heat or chemicals. Doesn't kill anything so, hard to find a place to put the filter when done. Cant alway catch toxins

How is cold used for microbial control? Is it microbicidal or microbiostatic?

Used to preserve microbes so it is microbiostatic

What is a fully formed, functional virus called?

Virion

What three major factors should be considered when choosing a drug?

What microorganism is, degree of susceptibility, medical condition of patient

How is microbial death defined?

When reproduction is permanently halted

How are viruses prevented and treated?

antivirals, interferon, vaccines

What is a typical pH range for bacterial growth? What do we call microbes living at extreme pHs?

between 6-8. Acidophiles live in acidic conditions. Alkaliphiles live in alkaline conditions.

What is the difference between chemically defined and complex media?

chemically defined: creating exact % complex: 1 or more not chemically defined

What occurs during incubation? how do we observe this on/in different physical states of media?

during incubation, microbes multiply. Liquid media: cloudiness solid media: colonies

What is exponential growth and why is it not sustainable?

exponential growth is growth rate that continues to increase over time. This is not sustainable because numerous factors prevent the bacteria from growing at this rate

What are the five steps of microbial characterization?

inoculation incubation isolation inspection identification

What is normally the effect of radiation on microbes?

kills most microbes

Each isolated colony originates from the growth of a single _________.

microbe/cell

Name and describe the oxygen usage patterns of microbes. Which of these can the human boy support? What is a capnophile?

Aerobes: use O2 at atmospheric levels to survive Microaerophiles: use little O2 to survive (organisms that live in soil or mammalian hosts) Anaerobes: don't use O2 (oral and intestinal bacteria) found in humans 1. Aerotolerant- tolerate O2 but won't use it 2. Facultative- doesn't need O2 but uses it if present (intestinal bacteria) 3. Obligate: die in presence of O2 4. Capnophile: thrive in high concentrations of carbon dioxide

What are the five main mechanisms of action of antibacterial drugs? Place the following drugs in the correct categories: penicillins ("-cillins"), cephalosporins (ceph/cef), carbapenems, vancomycin, isoniazid, bacitracin, polymyxin, fluroroquinolones, sulfa drugs, amnioglycosides (streptomycin), macrolides (all 3 examples), clindamycin, and tetracyclines.

1) Inhibition of cell wall synthesis (PENICILLIN, CEPHALOSPORIN, CARBAPENEMS, VANCOMYCIN, ISONIZID, BACITRACIN) 2) Inhibition of RNA and DNA structure and function (FLUOROQUINOLONES) 3) Inhibition of protein synthesis (AMINOGLYCOSIDES, MACROLIDES: ERYTHROMYCIN, CLARITRHOMYCIN, AZITHROMYCIN, CLINDAMYCIN, TERTRACYCLINES) 4) Interference with cytoplasmic membrane structure or function (POLYMYXIN) 5) Inhibition of folic acid synthesis (SULFA DRUGS)

What are the five main mechanism of drug resistance?

1) New enzymes are synthesized, inactivating the drug 2) Permeability or uptake of the drug into the bacterium is decreased 3) Drug is immediately eliminated 4) Binding site for drugs are decreased 5) An affective metabolic pathway is shut down or alternative pathway is used

What are the steps in the multiplication cycle of an animal virus? What is occurring in each step and where is it happening? What are the different means by which new viruses can be released from a cell?

1. Adsorption: virus docks with host cell 2. Penetration: getting inside and gets uncoded (when vacuole dissolves envelope and capsid) 3. Synthesis: making new DNA or RNA, viral components formed,. CELL becomes virus factory (virus takes over) 4. Assembly and release: Assembly builds all new parts that were made in synthesis (# of viruses depends on size and health of cell host)

What are the phases of bacterial population growth in culture? What is happening in each phase? Why is the growth curve relevant?

1. Lag phase: population stays the same as the microbes get used to the environment 2. Exponential phase: rapidly multiplying 3. Stationary phase: population stays the same because more are being made but the same amount are dying 4. Death phase: dying faster than producing

What do we call microbes that live in high solute concentrations? What about a microbe that specifically prefers a high-salt environment?

oenophiles live in high solute concentrations. Halophiles live in high salt concentrations

What is the mode of action of the following chemicals and what are their levels of microbial control, typical uses, advantages, and disadvantages: halogens hydrogen peroxide, aldehydes, gas sterilization, phenols, chlorhexidine, alcohols, detergent, heavy metals.

1. Halogens: Iodine, Chlorine, Denature enzymes, Sterilants, kills all microbes, remove organic matter before applying 2. Hydrogen Peroxide: forms toxic free radicals, can be sporicidal at high concentrations, good for tissues and delicate instruments 3. Aldehydes: Gluteraldyhyde is somewhat unstable but used frequently for cleaning medical equipment. Formaldehyde is toxic, irritating, carcinogenic, used for medical instruments, disrupts enzyme activity, sterilizes. 4. Gas sterilization: Ethylene Oxide, disrupts DNA replication, sporicidal, good for delicate and plastic instruments, carcinogenic, damaging to mucous membranes and explosive. 5. Phenol: Carbonic acids, disrupts cell walls or enzymes, sanitizes, used as standard for comparison, not used where people are, dangerous and irritating. 6. Chlorhexidine: destroys membranes and denatures proteins, fast, mild with low toxicity (used for mucous membrane, mouthwash, and scrubs) works on most vegetative bacteria, variable effectiveness on viruses and fungi. 7. Alcohol: Ethanol is isopropanol over 50% (70% ideal), disrupts cell membrane, cheap and non irritating, evaporates quickly, can cause damage to nervous system, used as antiseptic 8. Detergents: Household cleaners, Lysol, Spic n Span, disrupts selective permeability, not good for clinical setting, effective on viruses, algae, fungi, and gram positive bacteria. 9. Heavy Metal components: Silver or mercury, disrupts protein function, antiseptics (silver), preservatives (mercury), not effective on endospores, can be toxic and people can have allergies.

What are the non-symbiotic relationships? How do these relate to biofilms and antibiosis?

1. antagonism: one organism is working against another for resources (antibiosis: when one bacteria kills another) 2. Synergism: working together (biofilm: communities of bacteria that grow with/on each other to form cells and intracellular material)

What might cause a drug to be ineffective even after sensitivity tests have been completed?

1. inability of drug to diffuse into the body 2. Resistant microbes in the body that didn't make it to the test smaple 3. Infection caused by more than one pathogen 4. Antimicrobials taken incorrectly

How large are viruses, compared to other microbes? [approximate]

20nm-450nm

What are the major components of the cell?

70% water, protein, dry weight mostly organic CHNOPS, handful of nutrients= thousands of compounds

How is the viable plate count performed? What is it used for?

A sample is placed on a slide and all bacteria found under the microscope are counted

Since viruses are not alive, what words can we replace "alive" and "dead" for them?

Active vs inactive

What is an allergy? When does it usually present? What are some possible outcomes?

Allergies are an immune system response. It usually presents after the liver starts processing and it can be shown in rash, shock, or respiratory arrest.

What are some patent-based factors to consider in choosing an antimicrobial drug?

Allergies, liver or kidney, drug interactions, special cases, genetic/metabolic abnormalities, site of infection, route, and cost.

What is an enveloped virus? What is the envelope made of? What unique property does the envelope lend to the virus?

An enveloped virus is formed when the virus steals cellular membrane material from the host cell and creates an extra barrier around itself. Made of proteins It allows the virus to change shape!!!!! (pleomorphism)

What is the difference between an aqueous solution and tincture?

Aqueous solution: dissolved in H2O Tinctures: dissolved in alcohol

Which microbial types are the most resistance to microbial control agents?

Endospores

What two terms describe microbes based on where they get their carbon, and what is the difference?

Autotrophs: get their carbon from carbon dioxide Heterotrophs: get their carbon from consuming other living things

What is bacteriophage? What are the two possible reproduction cycles for phage? How does the lytic cycle compare to the reproduction cycle of animal viruses?

Bacteriophage: viruses that affect bacteria Reproduction cycles include: lytic and lysogeny Similar reproduction for animal viruses but phages do not absorb into the cell, instead they inject their DNA into the cell

What is the name for microbes that are adapted to high pressure environments? What happens if they are removed from this environment?

Barophiles live in high pressure environments, if they are removed they will rupture.

What is toxicity? Which organ/systems are commonly affected by toxicities?

Being toxic or poisonous. Lier and kidney, GI tract, CNS, Endocrine system, Skin

What is dessication? Why is it not effective and even potentially dangerous?

Desiccation: drying of microbes but can produce them to form endospores

What is meant by drug resistance? How do microbes develop drug resistance? What is a resistance factor? How does resistance spread?

Drug resistance is when the drug is not longer effective. Microbes develop this from gene mutations, secretion of new enzymes, reduction in permeability, drug pumps, alteration in drug binding sites, and change in metabolic pathway. It spreads when a microbes transfer their resistant DNA.

What is enriched media and why is it used?

Elements added to support growth

When might an antimicrobial be prescribed without having a definitive diagnosis? What is this called?

Empiric Theory given when identification is not yet confirmed

What is selective toxicity? Why is it important? When is it easier or more difficult to achieve?

Kills the invader not the host, important so the person that is sick gets better from the therapy and doesn't die from it. Easier when there is only one kind of invader.

How is the effectiveness of antimicrobial drugs tested? How is each test run and interpreted? What does each test tell us? What are the pros and cons of these tests? What is the relevance of the therapeutic index?

Kirby Bauer test: pure culture goes on agar disc, small antibiotic discs are placed in the dish, incubate overnight, measure zone of inhibition, compared to standard, interpret sensitivity. (R,I,S) EASY, REPRODUCIBLE, IN VITRO MATCHES IN VIVO. DOES NOT WORK FOR ANAEROBES OR SLOW GROWERS. QUALITATIVE NOT QUANTITATIVE (NO INFO ON DOSE0 Minimum inhibitory concentration: prepare antibiotics at known concentration, divide into test tubes diluting by 1/2 each time, inoculate organism into each tube, incubate under normal conditions, interpret: smaller concentration with no growth is the minimum inhibitory concentration. QUANTITATIVE, COMPARE TO DOSES TOLERATED BY PATIENTS, ALLOWS FOR ANAEROBES CAN BE AUTOMATED. MORE MATERIAL= HIGHER MONEY MORE ERRORS PRONE BY USING SEPARATE TUBES, LESS EFFICIENT

What tools and techniques are used for proper isolation?

Large flat surface, incubator, Petri dish, and inoculating tools.

what consistencies/textures can microbial media have? what material is used to make media solid? why is this material a good choice? In what situations would one choose each physical stat of media?

Liquid: good for O2 and pure cultures, semi solid, solid: good for isolation. Agar is used for solid media because microbes cannot eat through it, harmless, flexible, moldable, & holds moisture.

What is lyophilization and why is it used?

Lyophilization: freeze drying to preserve microbes

What usually happens to most microbes (or cells in general for that matter) in conditions that are not isotonic?

Lyse: explode Crenate: shrink

What is lysogny? what is a prophage? What is induction? How is this relevant to human disease?

Lysogeny is when the host chromosome carries bacteriophage DNA. Prophage is when the virus goes into an inactive state and enters into bacteria chromosome. The DNA will be contained not the bacterial cell and copied during its normal cell division. Induction is then the prophage in a lysogenic cell is activated and viral replication will begin and go right into the lytic cycle. Many bacteria that infect humans re lysogenized. This creates very deadly diseases such as Diphtheria, Cholera, and Botulism

How does macrolides polyenes, azaleas, echnocandins, and allylamines act against fungi? What is the major drawback of amphotericin B (one of the macrolide polyenes)?

Macrolide polyenes: disrupt selective permeability, very versatile, used to treat skin and mucous membrane lesions. Azoles: interfere with sterile synthesis, wide range of functions, skin, mouth, vagina, miconazole, ketoconazole, fluconazole, clotrimazole Echinocandins: inhibit cell wall synthesis, Candida and aspergillum, Micagungin. Allylamines: Enzyme inhibition, Terbinafne, Ringworm and cutaneous mycoses.

What are some common sources of antibiotics?

Microbes that produce them, and chemically synthesized.

What is a prion? What is it composed of? What does it do?

Misfolded proteins. Infections protein particles. Causes gradual degeneration of the brain and then death. Spongiform Encephalitis

What is the difference between a mixed culture & a pure culture?

Mixed: 2 or more species present Pure: one species present

What is moist heat more effective than dry heat? which methods of microbial control use dry heat? which methods of microbial control use moist heat? know the following for each type of heat: when is it used? How does it destroy microbes? What are the benefits and drawback?

Moist heat: limited to 100 degrees celsius, kills most vegetative pathogens in 30 minutes. Good for home uses Dry heat: burns hot, sterilizes fast. Toxins can be carried off in smoke.

What types of microbes are most resistant to disinfection/destruction? The least resistant?

Most resistant are nonpathogenic and microbes with endospores. Least resistant are vegetative microbes

What are viroids?

Naked strands of RNA. Infects plants, very small.

Why are viruses not considered to be alive?

Non-cellular, reliant on host, DNA or RNA (never both), obligate intracellular parasites

What drugs are commonly used against protozoans? What are some of the drugs commonly used against helminths?

Quinones & Quinolones are used against protozoans. Mebendazole and Albendazole are used against Helminths.

Describe the process of binary fission

Parent cells enlarges, duplicated its chromosomes, starts to pull its cell envelope to the center of the cell used a band of protein, cell wall forms created 2 daughter cells

How can we combine these terms to describe the four groupings of microbes based on energy and carbon sources?

Photoautotrophs (plants & algae), chemoautotrophs, photoheterotrophs, chemoheterotrophs (people/bacteria)

What two terms describe microbes based on where they get their energy, and what is the difference?

Phototrophs: get energy from light Chemotrophs: get their energy from chemicals

What are some new approaches to antimicrobial therapy?

RNAi, CRISPER, mimic defense peptides, drugs form non culturable bacteria, bacteriophages.

What is the function of viral spikes?

Protrusions off of the virus that helps it to stick to its host

What is meant by provirus, persistent infection, and chronic latent state? How are these connected?

Provirus: When the virus DNA is still in the DNA of host Chronic latent state: when viruses can stay dormant for a time and the reactivate Persistent infection: cells that continue to harbor virus

Proper isolation yields what kind of culture?

Solid media

Define the four possible outcomes of microbial control methods

Sterilization: everything killed Disinfection: all pathogens except ones with endospores, are killed Decontamination/sanitation: removing microbes to safe levels Antisepsis/Degermination: Removing microbes from living tissue

What are the effects of an oncovirus? What some known oncoviruses?

Transformation of the host cell (change in the DNA, HPV, mono, hepatitis)

How are viruses classified and named?

Structure, chemical composition, and genetic make up.

What is symbiosis? Describe the three categories of symbiosis in terms of the effect on the dependent and the host. Most of our normal flora fall into which categories?

Symbiosis is when two organisms live together in close partnership. 1. Mutualism: host and the dependent benefit from the relationship 2. Commensalism: Host is not affected, and the microbe benefits from the relationship (most of our normal flora fall into this category) 3. Parasitism: Harmful for the host, microbe benefits from the relationship

How can we help to prevent the further emergence of resistant bacteria?

Take antibiotics correctly, don't self prescribe, report adverse reactions, avoid antibiotics in food, keep good bacteria alive

What do the phrases "thermal death time" and "thermal death point" mean?

Thermal death time: define temp, how long will it take to kill the microbes Thermal death point: what temp point do I need to get to in 10 minutes

What makes satellite viruses different from other viruses?

They depends on other viruses for replication. Delta Agent

What is the difference between microbicidal and microbistatic agents? (Note: the roots on these words can change to fungi-, virus-, germi-, etc. and you should still know what they mean)

microbicidal: kills microbes microbiostatic: halts reproduction

What are the cardinal temperatures? What happens to microbes with different optimum temperatures? Which category do most human pathogens fall into?

minimum temp: lowest temp to get normal growth optimum temp: (range of what microbes grow best at) maximum temp: highest temp to survive Psychropiles: grow in COLD temperatures physchopiles: grow above freezing temperature (fridge-room temp) Mesophiles: 37 degrees is optimal thermophiles: grow at temperatures greater that 45 degrees extreme thermophiles: boiling to grow

What is general purpose media & why is it used?

most things grow on it, supports growth