Chapter 12 objectives

Question 1

All of the following pertain to cephalosporins except:

newer generations have activity against gram-negative bacteria.

many administered by injection, not orally.

have a beta-lactam ring.

are synthetic drugs.

Answer 1

are synthetic drugs

Question 2

Which of these drugs has the most narrow-spectrum activity?

aminoglycosides

isoniazid

erythromycin

cephalosporins

Answer 2

isoniazid

Question 3

The drug used against intestinal anaerobic bacteria, that can also alter normal biota leading to antibiotic-associated colitis, is

clindamycin.

ciprofloxacin.

gentamicin.

chloramphenicol.

Answer 3

clindamycin.

Question 4

Each of the following effect cell walls except

erythromycin.

vancomycin.

penicillin.

cycloserine.

Answer 4

erythromycin.

Question 5

Mebendazole, thiabendazole, and ivermectin are drugs used to treat _____ infections.

fungal

helminthic

bacterial

protozoan

Answer 5

helminthic

Question 6

Which of the following microbials does not inhibit DNA synthesis?

chloroquine

quinolone

penicillin

acyclovir

Answer 6

penicillin

Question 6

Nutrients that encourage the growth of beneficial microbes in the intestines are known as:

probiotics.

prebiotics.

riboswitches.

phytobiotics.

Answer 6

prebiotics.

Question 7

What type of chemical will allow some bacteria to be resistant to many penicillins?

aztreonam

synercid

penicillinase

imipenem

Answer 7

penicillinase

Question 8

The drug used for several protozoan infections is

metronidazole.

sulfa drugs.

griseofulvin.

amphotericin B.

Answer 8

metronidazole.

Question 9

A superinfection results from:

a decrease in most normal biota resulting in the overgrowth of an unaffected species.

build up of a drug to toxic levels in the patient.

an immune system reaction to the drug.

the wrong drug administered to the patient.

Answer 9

a decrease in most normal biota resulting in the overgrowth of an unaffected species.

Question 10

Each of the following is a mechanism for drug resistance transfer between microorganisms except

R-plasmids.

mutation.

conjugation.

Answer 10

mutation.

Question 11

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

synthetic drugs.

antibiotics.

semisynthetic drugs.

Answer 11

antibiotics.

Question 12

Microbial resistance resulting from mutation occurs because

All of the choices are correct.

prokaryotic genomes undergo mutation rapidly.

prokaryotic genomes undergo mutation often.

mutations are passed between organisms.

short generation times accumulate mutations in populations.

Answer 12

All of the choices are correct.

Question 13

The use of a drug to prevent imminent infection is called

synergism.

prebiotics.

prophylaxis.

Answer 13

prophylaxis

Question 14

It is better to use a broad-spectrum drug instead of a more specific, narrow-spectrum drug.

False

True

Answer 14

False

Question 15

You have given a dosage of an antibiotic to a patient for his infection, but the patient is not getting any better. The MIC tests shows that the drug that you prescribed, at the dosage that was given, should work against this particular strain of bacterium. What do you think might be the problem?

The patient is resistant to the drug.

The bacterium is immune to the chemical effects of the drug.

The drug might be broken down in the patient’s body before it can have its full effect on the bacterium.

Answer 15

The drug might be broken down in the patient’s body before it can have its full effect on the bacterium.

Question 16

The Kirby-Bauer test uses an agar surface, seeded with the test bacterium, to which small discs containing a specific concentration of several drugs are placed on the surface.

False

True

Answer 16

True

Question 17

Drugs that insert on the _____ ribosomal subunit prevent peptide bond formation or inhibit translocation of the subunit during translation.

70S

60S

50S

40S

Answer 17

50S

Question 18

The antifungal drug that can be used to treat serious systemic fungal infections is

metronidazole.

griseofulvin.

amphotericin B.

Answer 18

amphotericin B.

Question 19

Broad-spectrum drugs that disrupt the body’s normal biota often cause

nephrotoxicity.

superinfections.

allergic reactions.

Answer 19

superinfections.

Question 20

The cellular basis for bacterial resistance to antimicrobials include

synthesis of enzymes that alter drug structure.

All of the choices are correct.

alteration of drug receptors on cell targets.

prevention of drug entry into the cell.

bacterial chromosomal mutations.

Answer 20

All of the choices are correct.

Question 21

Alexander Fleming had been running tests using Staphylococcus, and left some plates out to incubate. Evidently, after returning to his lab after the weekend, he found that Penicillium mold was growing on his agar plates containing the growth of Staphylococcus. Looking more closely, he found a large, clear area around the mold colony where Staphylococcus colonies did not grow. Given this situation, a valid hypothesis would be that:

The Penicillium mold was being killed by the Staphylococcus.

The bacteriological medium being used in the plates was somehow inhibitory to the Staphylococcus growth.

The Staphylococcus was being inhibited by the Penicillium mold.

Answer 21

The Staphylococcus was being inhibited by the Penicillium mold.

Question 22

Which antimicrobial does not inhibit cell wall synthesis?

cephalosporins

penicillins

gentamicin

Answer 22

gentamicin

Question 22

Over 50 percent of all sales of medically important antibiotics in the United States are for livestock use. Why is this problematic for humans?

Resistant bacteria grow in the animals and may then be passed to humans.

The animals may become sick from the antibiotic ingestion.

The livestock will become resistant to the antibiotics and not respond to treatment when they have infections.

Answer 22

Resistant bacteria grow in the animals and may then be passed to humans.

Question 22

Bacteria can have a natural resistance to a drug which they have never been exposed. False True

Answer 22

True

Question 23

Side effects that occur in patient tissues while they are on antimicrobial drugs include all of the following except hepatotoxicity. diarrhea. deafness. development of resistance to the drug.

Answer 23

development of resistance to the drug.

Question 24

In a conversation with your friends from microbiology class, you are talking about drug resistance. The three of you disagree about the definition of the term so each of you state his or her definition and give a justification. Compare the various definitions and justifications below and pick the one that is most accurate. The person becomes resistant to the drug: The body adjusts to the dosage of the chemical and no longer responds to its action. The drug is changed in the body and is inactivated physically and chemically so it no longer works properly against the bacterium. The bacterium has changed physically or chemically in some way to be able to destroy the drug or avoid its action, allowing it to grow unimpeded by the drug.

Answer 24

The bacterium has changed physically or chemically in some way to be able to destroy the drug or avoid its action, allowing it to grow unimpeded by the drug.

Question 25

Which of the following is not used to treat malaria? primaquine metronidazole meflaquine

Answer 25

metronidazole

Question 26

Primaquine and chloroquine are drugs used in the treatment of ___ infections. protozoan gram-positive bacterial fungal

Answer 26

protozoan

Question 27

Drug susceptibility testing determines: the patient's response to various antimicrobials. if the drug is increasing to toxic levels in a patient. the pathogen's response to various antimicrobials.

Answer 27

the pathogen's response to various antimicrobials.

Question 28

An ideal antimicrobial therapeutic drug exhibits all of the following characteristics except nontoxic to host. easily broken down by host. easily administered.

Answer 28

easily broken down by host.

Question 29

Antibiotics which disrupt prokaryotic ribosomes can also affect eukaryotic small ribosomal subunit. eukaryotic large ribosomal subunit. eukaryotic mitochondrial ribosomes.

Answer 29

eukaryotic mitochondrial ribosomes.

Question 30

Which antibiotic is used to treat MRSA and VRE infections? azithromycin linezolid synercid

Answer 30

linezolid

Question 31

Antibiotics are derived from all of the following except: Cephalosporium. Staphylococcus. Bacillus.

Answer 31

Staphylococcus.

Question 32

Infections caused by gram-negative bacilli are often treated with aminoglycosides. penicillin G. synercid.

Answer 32

aminoglycosides.

Question 33

Indwelling catheter biofilm infections are more resistant to antibiotics than nonbiofilm infections. False True

Answer 33

True

Question 34

Which of the following is not a drug group used to treat fungal infections? quinolones macrolide polyene antibiotics flucytosine

Answer 34

quinolones

Question 35

What antibiotic is mixed with neomycin and polymyxin to make an antibiotic ointment (Neosporin) for superficial skin infections? streptomycin bacitracin chloramphenicol

Answer 35

bacitracin

Question 36

Which antimicrobial does not interfere with protein synthesis? chloramphenicol erythromycin trimethroprim

Answer 36

trimethroprim

Question 37

Ampicillin, amoxicillin, mezlocillin, and penicillin G all have a semisynthetic nature. an expanded spectrum of activity. a beta-lactam ring.

Answer 37

a beta-lactam ring.

Question 38

An antiviral that is a guanine analog would have an antiviral mode of action that bonds to ergosterol in the cell membrane. inhibits DNA synthesis. blocks penetration.

Answer 38

inhibits DNA synthesis.

Question 39

Your patient has been on antibiotics for 6 weeks after a case of streptococcal endocarditis, an infection of the inner heart wall. The infection clears up. However, the patient just visited you about a urinary tract infection, and the lab verified that the culprit was E. coli. What do you hypothesize happened in this situation? Her normal microbiota in the genitourinary tract were killed, allowing E. coli (not killed by the antibiotics) to establish an infection. The lab has made a mistake in identifying the cause, and, in fact, the endocarditis was caused by the E. coli. The antibiotics damaged her immune system, making her very susceptible to environmental bacteria.

Answer 39

Her normal microbiota in the genitourinary tract were killed, allowing E. coli (not killed by the antibiotics) to establish an infection.

Question 39

Sulfonamides are analogs of PABA and, as a result, they inhibit _____ synthesis. phospholipid folic acid protein

Answer 39

folic acid

Question 40

Penicillins and cephalosporins interfere with elongation of peptidoglycan. are metabolic analogs of PABA and block folic acid synthesis. block peptidases that cross-link glycan molecules.

Answer 40

block peptidases that cross-link glycan molecules.

Question 41

There are fewer antifungal, antiprotozoan, and antihelminthic drugs compared to antibacterial drugs because fungi, protozoa, and helminths do not cause many human infections. are so similar to human cells that drug selective toxicity is difficult to achieve. fewer target sites in their cells compared to bacteria.

Answer 41

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

Question 41

A chemical that inhibits beta-lactamase enzymes is: aztreonam. clavulanic acid. synercid.

Answer 41

clavulanic acid.

Question 42

Sulfa drugs work on folic acid biosynthesis. nucleic acid biosynthesis. ribosome biosynthesis.

Answer 42

folic acid biosynthesis.

Question 43

Antiviral drugs that target reverse transcriptase would be used to treat infections caused by: HIV. influenza A virus. hepatitis C virus.

Answer 43

HIV.

Question 44

The use of vaginal inserts of Lactobacillus to restore a healthy acidic environment is an example of prebiotics. probiotics. phytobiotics.

Answer 44

probiotics.

Question 45

Drugs that are hepatotoxic cause damage to a patient's kidneys. False True

Answer 45

False

Question 46

Sulfonamides are metabolic analogs of PABA and block folic acid synthesis. interfere with elongation of peptidoglycan. block peptidases that cross-link glycan molecules.

Answer 46

are metabolic analogs of PABA and block folic acid synthesis.

Question 47

Aminoglycosides: damage cell membranes. are metabolic analogs of PABA and block folic acid synthesis. attach to the 30S ribosomal subunit and disrupt protein synthesis.

Answer 47

attach to the 30S ribosomal subunit and disrupt protein synthesis.

Question 48

If pathogen A is more resistant to an erythromycin disc on a Kirby-Bauer plate compared to pathogen B, then pathogen A will have a/n _____ zone of inhibition compared to pathogen B. equal smaller larger

Answer 48

smaller

Question 49

Resistance genes can be transferred to other bacterial cells during transformation, transduction, and conjugation. False True

Answer 49

True

Question 50

The multidrug resistant pumps in many bacterial cell membranes function by bacterial chromosomal mutations. removing the drug from the cell when it enters. synthesis of enzymes that alter drug structure.

Answer 50

removing the drug from the cell when it enters.

Question 51

Which drug is used to treat cases of tuberculosis? tetracycline isoniazid penicillin G

Answer 51

isoniazid

Question 52

The _____ are drugs that deposit in developing teeth and cause a permanent brown discoloration. streptomycins tetracyclines penicillins

Answer 52

tetracyclines

Question 53

Who is considered to be the father of modern antibiotics? Crick Fleming Chargaff

Answer 53

Fleming

Question 54

Acyclovir is used to treat infections caused by: hepatitis C virus. herpes simplex virus. influenza A virus.

Answer 54

herpes simplex virus.

Question 55

The use of any chemical in the treatment, relief, or prophylaxis of a disease is called nephrotoxicity. selective toxicity. chemotherapy.

Answer 55

chemotherapy.

Question 56

Important characteristics of antimicrobial drugs include do not cause serious side effects in humans. All of the choices are correct. low toxicity for human tissues. high toxicity against microbial cells. stable and soluble in body tissues and fluids.

Answer 56

All of the choices are correct.

Question 57

What drug is used in cases of penicillin and methicillin resistance and also used to treat endocarditis? isoniazid erythromycin vancomycin

Answer 57

vancomycin

Question 58

Which of the following antibacterial drug groups does not target protein synthesis? macrolides aminoglycosides sulfonamides

Answer 58

sulfonamides

Question 59

A ratio of the dose of the drug that is toxic to humans versus the minimum effective dose for that pathogen is assessed to predict the potential for toxic drug reactions. This is called the: Kirby-Bauer technique. therapeutic index (TI). antibiogram.

Answer 59

therapeutic index (TI).

Question 60

An antibiotic of the penicillin family is penicillin G. False True

Answer 60

True

Question 61

All _____ consist of a thiazolidine ring, a beta-lactam ring, and an R group. aminoglycosides penicillins tetracyclines

Answer 61

penicillins

Question 62

Each of the following target prokaryotic ribosomes except: streptomycin. tetracycline. polymyxins.

Answer 62

polymyxins.