Материал: 2016_Kaplan_USMLE_Step_1_Lecture_Notes_Pharmacology

Table V-5-1. Antimicrobial Drug List

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Section V λ Antimicrobial Agents

1.A patient suffering from invasive aspergillosis is first administered NSAIDs, antihistamines, and adrenal glucocorticoids prior to administration of an antifungal drug. The antifungal drug works by

A.binding to tubulin

B.inhibiting squalene epoxidase

C.inhibiting thymine synthesis

D.binding to ergosterol

E.inhibiting 14α-demethylase

2.A patient is prescribed isoniazid prophylactically since another family member currently has tuberculosis. When the patient ends up getting tuberculosis despite prophylaxis, resistance to isoniazid is suspected. In what way did this resistance likely develop?

A.Decreased intracellular accumulation of the drug

B.Inactivation of the drug via N-acetyltransferases

C.Increased synthesis of mycolic acids

D.Mutations in the gene coding for DNA-dependent RNA polymerase

E.Reduced expression of the gene that encodes a catalase

3.A 7-year-old child presents with pharyngitis and fever of 2 days’ duration, and microbiology reveals small, translucent, beta-hemolytic colonies sensitive in vitro to bacitracin. Past history includes a severe allergic reaction to amoxicillin when used for an ear infection. The physician needs to treat this infection, but prefers not to use a drug that needs parenteral administration. Which one of the following agents is most likely to be appropriate in terms of both effectiveness and safety?

A.Azithromycin

B.Cefaclor

C.Doxycycline

D.Penicillin G

E.Vancomycin

4.A woman has a sexually transmitted disease, and the decision is made to treat her with antibiotics as an outpatient. She is warned that unpleasant reactions may occur if she consumes alcoholic beverages while taking this drug. The antibiotic can be identified as which of the following?

A.Ceftriaxone

B.Doxycycline

C.Metronidazole

D.Ofloxacin

E.Pen G

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Chapter 5 λ Antimicrobial Drug List and Practice Questions

5.An 82-year-old hospitalized patient with creatinine clearance of 25 mL/min has a microbial infection requiring treatment with antibiotics. Which of the following drugs is least likely to require a dosage adjustment, either a smaller dose than usual or an increased interval between doses?

A.Amphotericin B

B.Ceftriaxone

C.Gentamicin

D.Imipenem-cilastatin

E.Vancomycin

6.What drug is most likely to be effective in most diseases caused by nematodes?

A.Chloroquine

B.Mebendazole

C.Metronidazole

D.Praziquantel

E.Pyrimethamine

7.What antibiotic effectively treats a variety of causative organisms for bacterial pneumonia, and also works at the 50S ribosomal subunit?

A.Azithromycin

B.Ceftriaxone

C.Doxycycline

D.Ofloxacin

E.Clindamycin

8.In bacterial meningitis, third-generation cephalosporins are commonly drugs of choice. However, in neonatal meningitis they would not provide coverage if the infection was due to which of the following organisms?

A.Meningococci

B.L. monocytogenes

C.Pneumococci

D.E. coli

E.Group B streptococci

9.Which one of the following drugs inhibits bacterial protein synthesis, preventing the translocation step via its interaction with the 50S ribosomal subunit?

A.Clindamycin

B.Gentamicin

C.Chloramphenicol

D.Imipenem

E.Tetracycline

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Section V λ Antimicrobial Agents

10.Which of the following is a mechanism underlying the resistance of strains of S. pneumoniae to the widely used antibiotic ciprofloxacin?

A.Reduced topoisomerase sensitivity to inhibitors

B.Increased synthesis of PABA

C.Formation of methyltransferases that change receptor structure

D.Structural changes in porins

E.Formation of drug-inactivating hydrolases

11.Gentamicin would be an ineffective drug for which of the following organisms?

A.E. coli

B.B. fragilis

C.Pseudomonas

D.Listeria if combined with ampicillin

E.Proteus

12.In the treatment of a urinary tract infection in a patient known to have a deficiency of glucose-6-phosphate dehydrogenase, it would not be advisable to prescribe which of the following?

A.Ciprofloxacin

B.Amoxicillin

C.Cephalexin

D.Doxycycline

E.Sulfamethoxazole

13.What is the most likely mechanism of resistance for methicillin-resistant staphylococcus aureus to antistaph penicillins?

A.methylation of the binding site

B.active efflux of the drug from the bacteria

C.β-lactamase production

D.phosphorylation of the drug by bacterial enzymes

E.structural modifications of PBPs

14.Highly active antiretroviral therapy (HAART) in HIV infection is associated with which of the following?

A.A decrease in viral mRNA copies/mL of blood

B.A decrease in the rate of emergence of drug resistance

C.A possible increase in CD4 cell count

D.A reduced incidence of opportunistic infections

E.All of the above

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Chapter 5 λ Antimicrobial Drug List and Practice Questions

15.Oseltamivir and zanamivir are available for treatment of infections due to influenza A and B. The mechanism of their antiviral action is inhibition of which of the following?

A.RNA polymerase

B.Reverse transcriptase

C.Thymidine kinase

D.Neuraminidase

E.Aspartate protease

16.In a patient who has an established hypersensitivity to metronidazole, what is the most appropriate drug to use for the management of pseudomembranous colitis?

A.Ampicillin

B.Clindamycin

C.Doxycycline

D.Ofloxacin

E.Vancomycin

17.An AIDS patient who is being treated with multiple drugs, including AZT, lamivudine, indinavir, ketoconazole, and cotrimoxazole, develops breast hypertrophy, central adiposity, hyperlipidemia, insulin resistance, and nephrolithiasis. If these changes are related to his drug treatment, which of the following is the most likely cause?

A.Azidothymidine

B.Indinavir

C.Ketoconazole

D.Sulfamethoxazole

E.Trimethoprim

18.Which one of the following drugs is most suitable in an immunocompromised patient for prophylaxis against infection due to Cryptococcus neoformans?

A.Amphotericin B

B.Ampicillin

C.Fluconazole

D.Nystatin

E.Flucytosine

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