Chapter 12

important characteristics of microbial drugs include

important characteristics of microbial drugs include

all of these choices are correct
readily delivered to site of pathogen, lethal to pathogens, do not cause serious side effects in humans, remains active in body tissues and fluids

There are fewer antifungal, antiprotozoan, and antihelminth drugs compared to antibacterial drugs because these organisms

are so similar to human cells that selective drug toxicity is difficult to achieve

a semisynthetic antibiotic is a drug which is chemically modified in the laboratory after being isolated from natural sources

TRUE

When a patient's immune system reacts adversely to a drug, this serious side effect is called a superinfection.

FALSE

Drug susceptibility testing

determines the pathogen's response to various antimicrobics.

which of the following organisms would MOST likely be sensitive to natural penicillin

gram positive Streptococcus pyogenes

Which antimicrobic does not inhibit cell wall synthesis?

Polymyxin

salvarsan was

used to treat syphilis.

In the presence of penicillin, a cell dies because

it undergoes lysis.

the treatment of infection is much more effective when both sulfonamide and trimethoprim are used together than when taken alone. this is an example of

synergism

which of the following statements about drug resistance is FALSE

it is found only in gram-negative bacteria

Protozoan and helminthic diseases are difficult to treat because

their cells are structurally and functionally similar to human cells

A highly selective, narrow spectrum antibiotic is one best described as:

Specific to a few microbes and well tolerated by host

Niclosamide, a drug that prevents ATP generation in mitochondria. You would expect this drug to be effective against

helminths

drug suseptibility testing, like kirby-bauer, determines which of the following

the pathogen's response to various antimicrobics

all of the following information should be considered in managing antimicrobial drugs for a patient, except

there are no exceptions. all of this information is important
possible allergies, liver and/or kidney disease, age of patient, other drugs patient is taking

Antimicrobics effective against only gram-positive bacteria would be termed

narrow-spectrum drugs

a clinical microbiologist makes serial dilutions of several antimicrobics in broth, and then incubates each drug dilution series with a standard amount of a patients isolated pathogen. what is this microbiologist determining?

minimum inhibitory concentration (MIC)

why should countries ban the use of human drugs in animal feeds

because it contributes to the growing drug resistance problem

a superinfection results from

decrease in most normal flora with overgrowth of an unaffected species.

Penicillins and cephalosporins

block the peptidases that cross-link glycan molecules of PG.

Aminoglycosides

attach to the ribosomal subunit and disrupt protein synthesis

Rifampin is a drug that inhibits transcription. What is its 'mode of action'?

Disrupts nucleic acid synthesis

which of the following antimicrobials is contraindicated for children due to permanent tooth discoloration

tetracycline

Both trimethoprim and sulfamethoxazole inhibit reactions along the same metabolic pathway.

TRUE

Overgrowth of fungi after antibiotic use is commonly referred to as a superinfection

TRUE

which one of the following does NOT belong with the others

streptomycin

humans contribute to the development of antibiotic restraint strains of bacteria in which way

all of the above
overuse of antibiotics by physicians and self-medication with OTC antibiotics, by not taking the full measure of antibiotics according to prescription directions, routine use of antimicrobial chemicals in everyday products like soap and animal feed

drug resistance occurs

when antibiotics are used indiscriminately

bacteria capable of resisting the effects of antimicrobials may utilize which of the following mechanisms

any one of the above
altering the structure or presence of the drug's cellular target, enzymatically degrading the drug, eliminating the drug before it reaches the target, rerouting metabolic pathways

Most of the available antimicrobial agents are effective against

bacteria

The derivatives Ampicillin and Methicillin are examples of which of the following?

semi-synthetic beta lactams

Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because

the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal

A species of Bacillus produces the antibiotic bacitracin.

True

Important characteristics of antimicrobic drugs include

All of the choices are correct.; readily delivered to the site of infection.; high toxicity against microbial cells.; do not cause serious side effects in humans.; remains active in body tissues and fluids.

All of the following pertain to cephalosporins except

they are synthetic drugs.

Substances that are naturally produced by certain microorganisms that can inhibit or destroy other microorganisms are called

antibiotics

Some drugs are best administered parenterally. Why?

They are poorly absorbed from the intestine