Antimicrobial Treatments

anti-fungal drugs

1. nystatin 2. clotrimazole 3. ketoconazole 4. fluconazole

Beta-lactam antibiotics

All -cillins Imipenam Aztreonam Penicillins Cephalosporins Carbapenems Monobactams

chronic infection

An infection of long duration

Choose the statement that best describes superinfection.

An infection that occurs due to the overgrowth of other potentially pathogenic microbes during or after initial antimicrobial therapy

Beta-lactamases

Beta lactamases are enzymes made by some bacteria that inactivate penicillin and a number of other beta-lactam antibiotics. Some "-cillins" have been developed that are resistant to the activity of beta-lactamases, such as methicillin and cloxacillin. Other antibiotics have been developed that combine a beta-lactamase susceptible "-cillin," such as amoxicillin, with clavulanate, a beta-lactamase inhibitor, which will inhibit bacterial beta-lactamases and protect the amoxicillin from destruction.

Select all of the correct statements that apply to beta-lactamases.

Beta-lactamases are made by bacteria. Beta-lactamases can inactivate penicillin. Beta-lactamases are inactivated by a chemical called clavulanate.

Reverse transcriptase synthesizes

DNA from RNA

five basic ways that enable a microorganism to be resistant to an antimicrobial.

Decreased permeability to the antibiotic Microbe uses an alternative pathway to circumvent a blocked pathway Altered target site, such that the antibiotic can no longer bind to the target Antibiotic efflux pumps pump the antibiotic out of the cell Enzymatic inactivation of the antibiotic

cationic detergents

Effective disinfectants Kill most bacteria, but not mycobacterium tuberculosis or endospores Safe and easy to use, but inactivated by hard water and soap

Select the microorganism that is least resistant to chemical and physical control measures.

Enveloped viruses

elect the microorganism that is least resistant to chemical and physical control measures.

Enveloped viruses

Select the five major mechanisms of antimicrobial resistance.

Enzymatic inactivation of the antibiotic. Antibiotic efflux pumps pump the antibiotic out of the cell. Altered target site, such that the antibiotic can no longer bind to the target. Microbe uses an alternative pathway to circumvent the blocked pathway. Microbe uses an alternative pathway to circumvent the blocked pathway. Decreased permeability to the antibiotic.

True or False: Many antibiotic drugs exhibit a high level of selective toxicity because the structure targeted by the drug is common to both the infectious agent and the host.

False, many of these drugs are selectively toxic because they target structures that vary greatly between the host and infectious agent itself.

True or False: Superinfections are most likely to result from treatment with narrow spectrum antimicrobials.

False, superinfections are most likely to occur when an individual is treated with broad spectrum antimicrobials that deplete much of the normal microbiota.

Select the statements that accurately reflect the process of filtration.

Filters, charcoal, and diatomaceous earth can all be used to remove microbial contaminants in the process of filtration. Filters with pores of the smallest diameter are utilized to sterilize air and liquid samples. Filtration is beneficial in the preparation of products, such as serum, that cannot withstand high heat. Filtration uses filters or other substances to remove microbial contamination from air or liquids. Some filtration methods can sterilize a product, but it cannot remove soluble toxins.

steps involved in microbial disease

First, the organism must enter the body. Then, it must be able to attach to the host before it is expelled by body defenses. It must also continue to survive body immune defenses even after establishment. The microbe can cause direct damage to body tissues, an excessive immune response, and even epigenetic changes to the host cell. The pathogen finally exits the host to find new susceptible hosts.

Which of the drugs mentioned inhibits DNA polymerase?

Foscarnet

Stages in the course of infection and disease

Incubation time Prodromal stage Period of invasion Convalescent Period Terminal Stage

Of all the antiviral drugs mentioned, which is actually produced by the host?

Interferon

drugs and fluconazole is an antifungal.

Ivermectin and mebendazole are antihelminth

Polymyxins target

MOA: Disrupt bacterial/fungal cell membranes

Select the methods below that illustrate the use of moist heat to control microbes.

Methods using moist heat include boiling water, pasteurization, tyndallization, and the steam autoclave.

anti-protozoal drugs

Metronidazole (flagyl) Quinacrine (atabrine) Chloroquine (avalon) Artimisinin (to treat multi drug resistant strains of falciparum malaria)

During which stage of viral replication does amantadine exert its inhibitory effect?

Penetration and uncoating

Choose the antimicrobial category that is most selectively toxic.

Penicillins that inhibit cell wall synthesis.

The process that destroys or removes all viable microorganisms is called

Sterilization

Anticeptic

Substance that inhibit the growth of microorganisms on living tissue (e.g., alcohol and povidone-iodine solution.)

Select the anti-protozoal drugs from this list.

The anti-protozoal drugs include chloroquine, primaquine, quinacrine, and metranidazole.

Select antibiotics, other than beta-lactam drugs, that also inhibit bacterial cell wall synthesis.

The antibiotics in this list that inhibit cell wall synthesis and are NOT beta-lactam drugs are vancomycin, isoniazid, and bacitracin.

Select the major targets of antimicrobial therapy:

The five major targets are: cell wall synthesis; cell membrane structure/function; DNA/RNA structure/function; protein synthesis; and folic acid synthesis.

Sterilization

The process that completely destroys all microbial life, including spores.

Decontamination

The removal or cleansing of dangerous chemicals and other dangerous or infectious materials.

Select the three primary mechanisms by which anti-viral medications work.

The three primary ways in which anti-viral medications work include preventing entry of the virus into the host cell, blocking the transcription and translation of viral proteins, and preventing the maturation of viral particles.

two ways in which microorganisms acquire antimicrobial resistance

Transfer of genes from other microorganisms Spontaneous mutation

indirect transmission

Transmission of blood or body fluids through contact with an intermediate contaminated object such as a razor, extractor, nipper, or an environmental surface.

direct transmission

Transmission of blood or body fluids through touching (including shaking hands), kissing, coughing, sneezing, and talking.

The three most prevalent types of healthcare-associated infections

UTI, surgical site, respiratory

Select which of the following is a nonionizing form of radiation that is more often used for disinfection purposes.

UV radiation

Azoles

a group of drugs used to treat fungal infections include ketoconazole, fluconazole, clotrimazole, and miconazole

broad spectrum

ability of a drug to be effective against a wide range of microorganisms

primary infection

acute infection that causes the initial illness

systemic infection

an infection throughout the body

narrow spectrum

antimicrobials effective against a limited array of microbial types

The fluoroquinolones (quinolones) Some of the more commonly used quinolones include ofloxacin and ciprofloxacin.

are a group of antibiotics that interfere with DNA synthesis and transcription by inhibiting DNA gyrase and topoisomerase. Some newer quinolones include levofloxacin and trovafloxacin.

Aminoglycosides

attach to the 30S ribosomal subunit and disrupt protein synthesis

An antimicrobial drug that is effective against a very diverse array of bacteria is described as _____ spectrum, whereas a drug that is very selective for a just a few different types of bacteria is described as _______ spectrum.

broad, narrow

Target of antimicrobial agents?

cell membrane cell wall ribosomes/protein synthesis nucleic acid synthesis

Select the major cellular targets of physical and chemical control agents:

cell wall, the cell membrane, cellular synthetic processes, and proteins.

Penicillins and cephalosporins target

cell walls

Select which of the following represents a correct pairing of antimicrobial drug and cellular target:

cephalosporins, cell wall

acute infection

comes on rapidly, with severe but short-lived effects

Drugs that act by mimicking the normal substrate of an enzyme, thereby blocking its active site, are called

competitive inhibition

passive carrier

contaminated healthcare provider picks up pathogens and transfers them to other patients

epidemic disease

disease acquired by many hosts in a given area in a short time

endemic disease

disease constantly present in a population

sporadic disease

disease that occurs occasionally in a population

A ______ agent would be used to destroy bacteria on a countertop whereas an _______ agent would be used on skin prior to making an incision.

disinfectant, antiseptic

The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is

disinfection

competitive inhibition

drug competes with normal substrate for enzyme's active site

The production of beta-lactamases is an example of this mechanism of drug resistance:

drug inactivation

fluoroquinolones (quinolones)

effective against gram negative bacteria and some atypical bacteria(chlamydia, Mycoplasma, Legionella) Newer generation quinolones (levofloxacin , moxifloxacin, gatifloxacin) are also active against gram positve bacteria.

Beta-lactamases (penicillinases)

enzymes that break down beta-lactam rings of penicillin and similar molecules, rendering them inactive.

t/f A narrow spectrum antimicrobial would be an appropriate choice to treat an abscess caused by several different microbe species, including both gram-negative and gram-positive bacteria.

false A mixed infection caused by several different microbes would best be treated by a broad spectrum antimicrobial. A broad spectrum antimicrobial would also be appropriate in a situation in which the causative agent has not yet been isolated, identified, and tested for antimicrobial susceptibility. Once the culture and susceptibility test provide more information, a narrow spectrum drug could be substituted for the broad spectrum drug.

True or False: An effective antimicrobial drug will only destroy 30% of the host's cells.

false The two primary goals of antimicrobial treatment are to destroy and eradicate the infective agent while producing no toxic effects within the host.

t/f Drugs that block quorum-sensing pathways among bacterial cells have unfortunately been ineffective thus far in treating biofilm infections.

false Research into these drugs has actually shown great promise in the use of such pathway blocking drugs to prohibit and/or break down biofilm growth.

Select which non-beta-lactam phosphoric acid agent is used today as an alternative treatment for urinary tract infections caused by enteric bacteria:

fosfomycin

Ketoconazole, fluconazole, clotrimazole, and miconazole are broad-spectrum azoles used to treat _____ infections.

fungal

mixed infection

infection caused by two or more organisms

Superinfections can result from

infection with a multidrug resistant microorganism

point source epidemic

infectious agent came from a single source, and all of its "victims" were exposed to it from that source

Protease inhibitors

inhibit the processing of large viral proteins into individual components inhibit processing of long polypeptide chainsCorrectCorrect

Which of the following methods of action would be bacteriostatic?

inhibition of protein synthesis

anti-helminthic drugs from this list.

ivermectin, mebendazole, and praziquantel

Disenfection

kills bacteria but will not destroy completely refers to the removal of most vegetative pathogens (note that this does not include spores)`

Select the correct pairing of the antifungal drug and its application:

miconazole, vaginal infections

localized infection

microbes enter the body and remains confined to a specific tissue

The fluoroquinolones, or quinolone drugs, are a group of antimicrobials that inhibit:

nucleic acid structure and/or function

secondary infection

opportunistic infection after a primary (predisposing) infection

chronic carrier

person with a latent infection who sheds the infectious agent

Ionizing radiation such as gamma radiation is used for cold sterilization of a variety of items, including

plastics, pharmaceuticals, and foods.

Select which of the following strategies involves the use of nutrients to directly encourage the growth of existing healthy biota:

prebiotics

The two microbial forms most resistant to chemical and physical control measures are _____ or proteinaceous infectious particles, and ______ produced by Bacillus and Clostridium species.

prions, endospores

tetracycline target

protein synthesis, 30s ribosomes

convalescent carrier

recuperating without symptoms

common source epidemic

result from common exposure to a single source of infection over a period of time

propagated epidemic

results from an infectious agent that is communicable from person to person and is sustained over time in a population

thermal death time

shortest length of time required to kill all test microbes at a specified temperature

asymptomatic carrier

shows no symptoms

Incubating carriers what are they

spread the infectious agent during the incubation period Spreads the infectious agent before the appearance of the first symptoms

Cationic detergents are surface active agents, also known as _____, which damage bacteria by binding bacterial surface proteins and disrupting _____.

surfactants, cell membranes

focal infection

systemic infection that began as a local infection

thermal death point

the lowest temperature required to kill all microbes in a sample in 10 minutes The more heat-tolerant an organism, the higher its thermal death point.

thermal death rate

the lowest temperature that will kill all the microbes in 10 minutes

therapeutic index

the ratio between the toxic and therapeutic concentrations of a drug The ratio of the toxic dose of a drug to its therapeutic dose is the therapeutic index (TI) of the drug. Ideally, dosages should be high enough to inhibit the microbe but not cause toxicity in the patient. The higher the TI, the greater the margin of safety.

The ratio of the toxic dose of an antimicrobial drug (that is toxic to humans) to its minimum therapeutic dose is the ______.

therapeutic index

vector transmission

transmission of an infectious agent by an insect, arthropod, or animal

A chemical labeled as bactericidal will kill bacteria whereas a chemical labeled as bacteriostatic will inhibit bacterial growth but will not kill them.

true

True or False: Penicillins account for the greatest number of antimicrobial allergies today.

true True, and these are followed by allergic reactions to sulfonamides.

Resident microbiota can cause disease in some individuals if they gain access to the correct portal of entry. True or False

true True, endogenous microbes can still cause disease, especially in immunocompromised individuals. Even in healthy individuals, endogenous microbes can cause disease if they invade a different tissue of the body where they can multiply and cause damaging effects. One example is E. coli that colonizes the colon, but can be transmitted to the urinary tract through poor sanitary practices and cause a urinary tract infection (UTI).

t/f A chemical labeled as bactericidal will kill bacteria whereas a chemical labeled as bacteriostatic will inhibit bacterial growth but will not kill them.

true Any agent labeled "-cidal" will kill the target organism. A bactericidal chemical will kill bacteria. A chemical labeled as bacteriostatic will not kill, but will inhibit the growth of the bacteria. The root "-static" means to stop or inhibit.

true or false Species of Bacillus produce bacitracin and the polymyxin drugs.

true Bacitracin is produced by a strain of Bacillus subtilis and polymixins are produced by Bacillus polymyxa

When AZT is present, which enzyme is inhibited?

viral reverse transcriptase

pandemic disease

worldwide epidemic