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44 Cards in this Set
- Front
- Back
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1. The primary mechanism of antibacterial action of the penicillins involves inhibition of:
a. Beta-lactamases b. N-acetylmuramic acid synthesis c. Peptidoglycan cross-linking’ d. Synthesis of cell membranes e. Transglycosylation |
C. Peptidoglycan cross linking
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2. Which statement about imipenem is accurate?
a. Active against methicillin-resistant staphylococci b. Has a narrow spectrum of antibacterial action c. In renal dysfunction, dosage reduction is necessary to avoid seizures d. Is highly susceptible to beta-lactamases produced by Enterobacter species e. Is used in fixed combination with sulbactam |
C. In renal dysfunction, dosage reduction is necessary to avoid seizures
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A 36-year-old woman recently treated for leukemia is admitted to the hospital with malaise, chills, and high fever. Gram stain of blood reveals the presence of gram-negative bacilli. The initial diagnosis is bacteremia, and parenteral antibiotics are indicated. The records of the patient reveal that she had a severe urticarial rash, hypotension, and respiratory difficulty after oral penicillin V about 6 mo ago. The most appropriate drug regimen for empiric treatment is:
a. Aztreona b. Cefazolin c. Imipenem d. Nafcillin e. Ticarcillin plus clavulanic acid |
a. aztreona
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A 52-year-old man (weight 70kg) is brought to the hospital emergency department in a confused and delirious state. He has had an elevated temperature for more than 24 h, during which time he had complained of a severe headache and had suffered from nausea and vomiting. Lumbar puncture reveals an elevated opening pressure, and cerebrospinal fluid findings include elevated protein, decreased glucose, and increased neutrophils. Gram stain of a smear of csf reveals gram-positive diplococci, and a preliminary diagnosis is made of purulent meningitis. The microbiology report informs you that for approximately 15% of S pneumoniae isolates in the community, the minimal inhibitory concentration for penicillin G is 20mcg/ml.
4. Treatment of this patient should be initiated immediately with intravenous administration of: a. Ampicillin-sulbactam b. Cefazolin c. Cefotaxime plus vancomycin d. Nafcillin e. Ticarcillin |
C. Cefotaxime plus Vanco
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Resistance of pneumococci to penicillin G is due to
a. Beta-lactamase production b. Changes in chemical structure of target penicillin binding proteins c. Changes in porin structure d. Changes in D-Ala-D-Ala building block of peptidoglycan precursor (resistant to vanco) e. Decreased intracellular accumulation of penicillin G |
B. Changes in chemical structure of target penicillin binding proteins
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If this patient had been 82 years old and the Gram stain of the smear of csf had revealed gram-positive rods resembling diphteroids, the antibiotic regimen for empiric treatment would include
a. Ampicillin b. Aztreonam c. Cefazolin d. Fosfomycin e. Meropenem |
a. Ampicillin
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A patient needs antibiotic treatment for native valve, culture-positive infective enterococcal endocarditis. His medical history includes a severe anaphylactic reaction to penicillin G during the last year. The best approach would be treatment with
a. Amoxicillin-clavulanate b. Aztreonam c. Cefazolin plus gentamicin d. Meropenem e. Vancomycin |
e. Vancomycin
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Which statement about vancomycin is accurate?
a. Active against methicillin-resistant staphylococci b. Bacteriostatic c. Binds to penicillin-binding proteins (PBPSs) d. Hepatic metabolism e. Oral bioavailability |
a. active against methicillin-resistant staphylococci
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A 2-year-old child is brought to the hospital after ingesting pills that a parent had used for bacterial dysentery when traveling outside the United States. The child has been vomiting for more than 24h and has had diarrhea with green stools. He is now lethargic with an ashen color. Other signs and symptoms include hypothermia, hypotension, and abdominal distention. The drug most likely to be the cause of this problem is
a. Ampicillin b. Chloramphenicol c. Clindamycin d. Doxycycline e. Erythromycin |
B. Chloramphenicol
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The mechanism of antibacterial action of doxycycline involves:
a. Antagonism of bacterial translocase activity b. Binding to a component of the 50S ribosomal subunit c. Inhibition of DNA-dependent RNA polymerase d. Interference with binding of aminoacyl-tRNA to bacterial ribosomes e. Selective inhibition of ribosomal peptidyl transferases |
D. interference with binding of aminoacylt-rRNA to bacterial ribosomes
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11. Clarithromycin and erythromycin have very similar spectra of antimicrobial activity. The major advantage of clarithromycin is that it
a. Does not inhibit hepatic drug-metabolizing enzymes b. Eradicates mycoplasmal infections in a single dose – c. Has greater activity against M avium-intracellulare complex d. Is active against methicillin-resistant strains of staphylococci e. Is active against strains of streptococci that are resistant to erythromycin |
C. Has greater activity against M avium intracellular complex
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12. The primary mechanism of resistance of gram-positive organisms to erythromycin is
a. Decreased activity of uptake mechanisms b. Decreased drug permeability of the cytoplasmic membrane c. Formation of drug-inactivating acetlytranserases d. Formation of esterases that hydrolyze the lactone ring e. Methylation of binding sites on the 50S ribosomal subunit |
e. methylation of binding sites on the 50s ribosomal subunit
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A 55-year-old patient with a prosthetic heart valve is to undergo a periodontal procedure involving scaling and root planning. Several years ago, the patient had a severe allergic reaction to procaine penicillin G. Regarding prophylaxis against bacterial endocarditis, which one of the following drugs taken orally is most appropriate?
a. Amoxicillin 10 min before the procedure b. Clindamycin 1 h before the procedure c. Erythromycin 1h before the procedure and 4 h after the procedure d. Vancomycin 15 min before the procedure e. No prophylaxis is needed because this patient is in the negligible risk category |
B. Clindamycin
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A 24-year-old woman comes to a clinic with complaints of dry cough, headache, fever, and malaise, which have lasted 3 or 4 d. She appears to have some respiratory difficulty, and chest examination reveals rales but no other obvious signs of pulmonary involvement. However, extensive patchy infiltrates are seen on chest x-ray film. Gram stain of expectorated sputum fails to reveal any bacterial pathogens. The patient mentions that a colleague at work has similar symptoms to those she is experiencing. The patient has no history of serious medical problems. She takes loratadine for allergies and supplementary iron tablets, and she drinks at least 6 cups of caffeinated coffee per day. The physician makes an initial diagnosis of community-acquired pneumonia.
14. Regarding the treatment of this patient, which of the following drugs is most suitable? a. Amoxicillin b. Clindamycin c. Doxycycline d. Linezolid e. Vancomycin |
C. Doxycycline
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15. If this patient were to be treated with macrolide erythromycin, she should
a. Avoid exposure to sunlight b. Avoid taking supplementary iron tablets c. Decrease her intake of caffeinated beverages d. Discontinue loratadine temporarily e. Have her plasma urea nitrogen or creatinine checked before treatment |
C. Decrease her intake of caffeinated beverages
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A 5-day course of treatment for community-acquired pneumonia would be effective in this patient with little risk of drug interactions if the drug prescribed were:
a. Ampicillin b. Azithromycin c. Clindamycin d. Erythromycin e. Vancomycin |
B. Azithromycin
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Concerning quinupristin-dalfopristin, which statement is accurate?
a. Active in treatment of infections caused by E. faecalis b. Bacteriostatic c. Hepatotoxicity has led to FDA drug alerts d. Induce formation of hepatic drug-metabolizing enzymes e. Used in management of infections caused by multidrug-resistant streptococci |
e. used in management of infections caused by multi-drug resistant sterptococci
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Regarding the mechanism of action of aminoglycosides, the drugs
a. Are bacteriostatic b. Bind to the 50S ribosomal subunit c. Cause misreading of the code on the mRNA template d. Inhibit peptidyl transferase e. Stabilize polysomes |
C. cause misreading of the code on the mRNA template
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All of the following statements about the clinical uses of aminoglycosides are accurate EXCEPT:
a. Effective in the treatment of infections caused by Bacteroides fragilis b. Gentamicin is used with ampicillin for synergistic effects in the treatment of enterococcal endocarditis c. Often used in combination with cephalosporins in the empiric treatment of life-threatening bacterial infections d. Owing to their polar nature, aminoglycosides are not absorbed after oral administration |
a. effective in tx of infections caused by bacteroides fragilis
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Which statement is accurate regarding the antibacterial action of gentamicin?
a. Antibacterial activity is often reduced by the presence of an inhibitor of cell wall synthesis b. Antibacterial action is not concentration-dependent c. Antibacterial action is time-dependent d. Efficacy is directly proportional to the duration of time that the plasma level is greater than the minimal inhibitory concentration – post abx effective e. Gentamicin continues to exert antibacterial effects even after plasma levels decrease below detectable levels |
e. gentamicin continues to exert antibacterial effects even after plasma levels decrease below detectable levels
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Regarding the toxicity of aminoglycosides, which statement is accurate?
a. Gentamicin and tobramycin are the least likely to cause renal damage b. Ototoxicity due to amikacin and gentamicin includes vestibular dysfunction that is often irreversible c. Ototoxicity is reduced if loop diuretics are used to facilitate aminoglycoside renal excretion d. With traditional dosage regimens, the earliest sign of nephrotoxicity is a reduced blood creatinine |
B. Ototoxicity due to Amikacin and gentamicin includes vestibular dysfunction that is often irreversity
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Which statement about “once daily” dosing with aminoglycosides is not accurate?
a. Convenient for outpatient therapy b. Dosage adjustment is less important in renal insufficiency c. Less nursing time is required for drug administration d. Often less toxic than conventional (multiple) dosing regimens e. Underdosing is less of a problem |
B. Dosage adjustment is less important in renal insufficiency
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Trimethoprim-sulfamethoxazole is established to be effective against which of the following opportunistic infections in the AIDS patient?
a. Cryptococcal meningitis b. Disseminated herpes simplex c. Oral candidiasis d. Toxoplasmosis e. Tuberculosis |
d. toxoplasmosis
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A 24-year-old woman has returned from a vacation abroad suffering from traveler’s diarrhea, and her problem has not responded to antidiarrheal drugs. A pathogenic gram-negative bacillus is suspected. Which drug is most likely to be effective in the treatment of this patient?
a. Amoxicillin b. Ciprofloxacin c. Sulfacetamide d. Trimethoprim e. Vancomycin |
B. Ciprofloxacin
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Which statement about the fluoroquinolones is accurate?
a. A fluoroquinolone is the drug of choice for treatment of an uncomplicated urinary tract infection in a 7-year-old girl b. Antacids increase the oral bioavailability of fluoroquinolones c. Gonococcal resistance to fluoroquinolones may involve changes in DNA gyrase d. Modification of moxifloxacin dosage is required in patients when creatinine clearance is less than 50ml/min e. The fluoroquinolones are contraindicated in patients with hepatic dysfunction |
C. Gonococcal resistance to fluoroquinolones may involve changes in DNA gyrase
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Which adverse effect is most likely to occur with sulfonamides?
a. Fanconi’s aminoaciduria syndrome b. Hematuria c. Kernicterus in the newborn d. Neurologic dysfunction e. Skin reactions |
C. Kernicterus in the newborn
E. skin reactions |
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Which statement about ciprofloxacin is accurate?
a. Active against most MRSA strains of staphylococci b. Antagonism occurs if it is used with inhibitors of dihydrofolate reductase c. During treatment, tendonitis and even tendon rupture may occur d. Most “first-time” urinary tract infections are resistant to ciprofloxacin e. Organisms associated with middle ear infections are highly resistant |
C. during treatment, tendonitis and even tendon rupture may occur
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A young woman is brought to a hospital emergency department with intense abdominal pain of 2 d duration. The pain has spread to the right lower quadrant and is accompanied by nausea, vomiting, and fever. She arrives at the ED with a blood pressure of 85/45, pulse 120/min, and temperature of 40C. Her abdomen has a board-like rigidity with diffuse pain to palpitation. Laboratory values include the following:WBC 20,000/uL and creatinine 1.5 mg/dL. After abdominal x-ray films are taken, a preliminary diagnosis of abdominal sepsis is made, possibly resulting from bowel perforation. After appropriate samples are sent to the laboratory for culture, the patient is hospitalized, and antimicrobial therapy is started with intravenous ampicillin and gentamicin.
Regarding the treatment of this patient, which statement is accurate? a. A Gram stain of the blood would provide positive identification of the specific organism involved in this infection b. Cultures are pointless because this is probably a mixed infection c. Empiric antimicrobial therapy of abdominal sepsis should always include a third-generation cephalosporin d. The antibiotic regimen should include a drug active against anaerobes e. The combination of ampicillin and gentamicin provides good coverage for all likely pathogens |
d. the antibiotic regimen should include a drug active against anaerobes
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If the antibiotic regimen in this patient is modified to include metronidazole
a. Ampicillin should be excluded from the regimen - b. Coverage will be extended to methicillin-resistant staphylococci c. Gentamicin should be excluded from the regimen d. Metronidazole should not be administered intravenously e. The patient should be monitored for candidiasis |
e. The patient should be monitored for candidiasis
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A 33-year-old man was seen in a clinic with a complaint of dysuria and urethral discharge of yellow pus. He had a painless clean-based ulcer on the penis and nontender enlargement of the regional lymph nodes. Gram stain of the urethral exudate showed gram-negative diplococci within polymorphonucleocytes. The patient informed the clinic staff that he was unemployed and had not eaten a meal for 2 days.
The most appropriate treatment of gonorrhea in this patient is: a) Ampicillin orally for 7 days b) Ceftriaxone intramuscularly as a single dose c) Procaine penicillin G intramuscularly as a single dose plus oral probenecid d) Tetracycline orally for 5 days e) Vancomycin intramuscularly as a single dose |
B. ceftriaxone IM as a single dose
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Immunofluorescent microscopic examination of fluid expressed from the penile chancre of this patient revealed treponemes. Because he appears to be infected with Treponema pallidum, the best course of action would be to:
a) Administer a single oral dose of fosfomycin b) Give no other antibiotics because drug treatment of gonorrhea provides coverage for incubating syphilis c) Injedct intramuscular benzathine penicillin G d) Treat with oral tetracycline for 7 days e) Treat with vancomycin |
C. Inject IM benzathine PCN G
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A 26-year-old woman was treated for a suspected chlamydial infection at a neighborhood clinic. She was given a prescription for oral doxycycline to be taken for 10 days. Three weeks later, she returned to the clinic with a mucopurulent cerivicitis. On questioning she admitted not having the prescription filled. The best course of action at this point would be to:
a) Delay drug treatment until the infecting organism is identified b) Rewrite the original prescription for oral doxycycline c) Treat her in the clinic with a single oral dose of cefixime d) Treat her in the clinic with a single oral dose of azithromycin e) Write a prescription for oral erythromycin for 10 days |
d) Treat her in the clinic with a single oral dose of azithromycin
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A 23-year-old female patient is pregnant and has gonorrhea. The medical history includes anaphylaxis following exposure to amoxicillin. The most appropriate drug to use is:
a) Azithromycin b) Cefixime c) Ceftriaxone d) Ciprofloxacin – cant use in pregnant patient e) Doxycycline – cant use in pregnant patient |
A) Azithromycin
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A 31-year-old man has gonorrhea. He has no drug allergies, but a few years ago acute hemolysis followed use of an antimalarial drug. The physician is concerned that the patient has an accompanying urethritis caused by C trachomatis, although no cultures or enzyme tests have been performed. Which of the following drugs will be reliably effective against both gonococci and C trachomatis and safe to use in this patient?
a) Cefixime b) Ciprofloxacin c) Spectinomycin d) Sulfamethoxazole-trimethoprim e) None of the above |
e. none of the above
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Which drug is effective in the treatment of nocardiosis and in combination with pyrimethamine, is prophylactic against Pneumocystis jiroveci infections in AIDS patients?
a) Amoxicillin b) Ciprofloxacin c) Clindamycin d) Sulfadiazine e) Trimethoprim |
D. Sulfadiazine
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A hospitalized AIDS patient is receiving antiretroviral drugs but no antimicrobial prophylaxis. He develops sepsis with fever, suspected to be caused by a gram-negative bacillus.
Antimicrobial treatment of this severely immune-depressed patient should not be initiated before: 1. Antipyretic drugs have been given to reduce body temperature 2. Infecting organism(s) have been identified by the microbiology laboratory 3. Results of a Gram stain are available 4. Results of antibacterial drug susceptibility tests are available 5. Specimens have been taken for laboratory tests and examinations |
5. specimens have been taken for lab tests and examination
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If the aminoglycoside gentamicin is used in the treatment of this patient, monitoring of serum drug level may be advised because the drug:
a. Does not penetrate into cerebrospinal fluid b. Has a narrow therapeutic window c. Is antagonized by beta-lactam antibiotics d. Is metabolized by hepatic enzymes e. Is hematoxic |
B.
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A combination of drugs might be given to this patient to provide coverage against multiple organisms or to obtain a synergistic action. Examples of antimicrobial drug synergism established at the clinical level include:
a. Amphotericin B with flucytosine in cryptococcal meningitis b. Carbenicillin with gentamicin in pseudomonal infections c. Rifampin with vancomycin in enterococcal infections d. Trimethoprim with sulfamethoxazole in coliform infections e. All of the above |
e
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Assuming that the physician assistant is concerned about the effects of renal impairment on drug dosage in this patient, which drug would not require dosage modification in renal dysfunction?
a. Amikacin b. Erythromycin c. Ofloxacin d. Trimethoprim-sulfamethoxazole e. Vancomycin |
b
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Which antibacterial agent appears to be the safest to use in the pregnant patient?
Azithromycin Clarithromycin Kanamycin Sulfadiazine Tetracycline |
azithromycin
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Which statement about the proposed drug management of this patient is not accurate?
a. Enteric gram-negative rods, anaerobes, enterococci, and group B streptococci are likely pathogens b. In this type of surgical procedure, antimicrobial prophylaxis has documented efficacy c. Nosocomial infection will be prevented by treatment throughout the period of hospitalization d. This drug will not be effective against anaerobes e. Without prophylaxis, the infection rate following this procedure exceeds 5% under optimal conditions |
C.
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Which drug increases the hepatic metabolism of other drugs?
a. Clarithromycin b. Erythromycin c. Ketoconazole d. Rifampin e. Ritonavir |
d. rifampin
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If ampicillin and piperacillin are used in combination in the treatment of infections resulting from Pseudomonas aeruginosa, antagonism may occur. The most likely explanation is that:
a. Ampicillin is bacteriostatic b. Ampicillin induces beta-lactamase production c. Autolytic enzymes are inhibited by piperacillin d. Piperacillin blocks the attachment of ampicillin to penicillin-binding proteins e. The 2 drugs form an insoluble complex |
B
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In a patient suffering from pseudomembranous colitis due to C. difficile with established hypersensitivity to metronidazole the most likely drug to be of clinical value is:
a. Chloramphenicol b. Clindamycin c. Doxycycline d. Levofloxacin e. Vancomycin |
e
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