Ther 201 Exam 3 Flashcards
TRUE or FALSE
1) Having a previous hypersensitivity reaction to
penicillin G would also predispose the patient to
having a hypersensitivity reaction to another
penicillin like piperacillin.
TRUE. Penicillins exhibit cross-allergenicity, meaning
their structures are sufficiently similar to elicit similar
hypersensitivity reactions. From Katzung: “All penicillins
are cross-sensitizing and cross-reacting.” (12th edition, p.796).
2) In treating bacterial infections in immunocompromised patients, such as those with leukemia, a bacteriostatic agent is insufficient.
TRUE. Bacteriostatic agents do not completely eliminate bacteria, they simply prevent bacteria from reproducing. These bacteria may then continue to grow in more favorable conditions, such as when host defenses go down or when the bacteriostat is removed. Thus, bacteriostatic agents work best in conjuction with intact host defenses. In immunocompromised patients, this would be detrimental as they are not able to mount a strong enough immune response.
3) Physicians may follow the typhoid treatment guidelines for India for treatment of patients with typhoid in the Philippines.
FALSE. Statistics where these guidelines are based will not be the same across countries. Parameters such as prevalence or antibiotic resistance, for example, will differ.
4) Updating treatment guidelines for infectious diseases is not necessary.
FALSE. It is necessary because bacteria continuously evolve, drug research is a very active field, resistance patterns often change, etc.
5) Resistance patterns for Streptococcus pneumonia are similar all over the world.
FALSE. Resistance patterns depend on a variety of factors such as government control programs, sanitation, and health practices. These would differ across countries.
6) Physicians must have current knowledge on the epidemiology of infectious disease in their locality.
TRUE. Some infectious diseases are endemic to particular regions, prevalence rates may be higher for a certain region compared to another, and physicians must be aware of these in order to properly manage their patients.
Matching type (MOA)
7) Erythromycin
Macrolides
Macrolides, tetracyclines: Inhibit protein synthesis by binding to rRNA subunits (30S for tetracylines and 50S for macrolides, also chloramphenicol)
8) Cotrimoxazole
B. CLASS: Sulfonamide-trimethoprim.
Sulfonamide-trimethoprim: Sulfonamides inhibit dihyropteroate synthase and trimethoprims inhibit dihyrofolate reductase. Endpoint is inhibition of folate synthesis.
9) Ciprofloxacin
C. CLASS: Quinolones.
Quinolones: Inhibit DNA synthesis by binding to DNA gyrase, an enzyme required for producing properly-coiled DNA prior to replication.
10) Tetracycline
A. CLASS: Tetracyclines.
11) Cefepime
D. CLASS: Cephalosporins (fourth-generation)
12) Ampicillin
D. CLASS: Aminopenicillins.
Penicillins: Inhibit cell wall synthesis by interfering with the transpeptidation reaction of bacterial cell wall synthesis.
13) Vancomycin
D. CLASS: Glycopeptides. (also inhibit cell-wall biosynthesis by binding to D-alanyl-D-alanine moiety of cell wall precursor)
14) _________ is a semi-quantitative antibiotic susceptibility test using paper discs impregnated with an antibiotic and after incubation with the bacteria to be test, the zone of inhibition is measured.
A. Kirby-Bauer method
B. Broth dilution test
C. Minimum inhibitory concentration
D. Hudgen’s test
A. Intro to Antipathogens and Antimicrobials trans. Also known as the disc diffusion assay. A lawn of bacteria is cultured with antiobiotic-impregnated discs and zones of
clearing around the discs are measured. If the diameter of the zone is greater than a certain size, the bacteria is susceptible to the antibiotic in the disc, but if the diameter is below the defined size, the antibiotic will most likely not inhibit the bacteria.
15) The following data is given for a disk diffusion test using N. gonorrhea and ceftriaxone:
Zone diameter breakpoint Sensitive Resistant
Ceftriaxone 35 34
The zone diameter seen for the isolate of N. gonorrhea from the penile discharge was 30 mm. Which of the following is a correct statement.
A. The patient will most likely have poor response to ceftriaxone
B. The patient most likely will be cured with ceftriaxone
C. It is safe to give the patient 10x the dose of ceftriaxone to ensure cure
A. The smaller the zone of clearing around the disc, the more the bacteria is resistant to the drug in the disc.
16) In comparison to the natural penicillins, the aminopenicillins have added activity against
A. Pseudomonas aeruginosa
B. Listeria monocytogenes
C. Staphylococcus aureus
D. Bacteroides fragilis
A. Ampicillins have extended activity against gram-negative microorganisms, such as P. aeruginosa.
17) True of oxacillin EXCEPT
A. Has good activity against staphylococcus
B. May be given for Klebsiella pneumoniae
C. Has a short half-life
D. Has good activity against streptococcus
B. Oxacillin CLASS: Penicillins, anti-staphylococcal. Resistant to staphylococcal B-lactamases, but can also be used against streptococci. This cannot be used against gram-negative bacteria as well as enterococci and anaerobic bacteria. K. pneumoniae is gram-negative.
18) The following statement is true of piperacillin EXCEPT
A. It is an extended spectrum penicillin
B. Has activity against anaerobes
C. May be used for methicillin-resistant S. aureus infections
D. Is effective against P. aeruginosa sepsis
C. Vancomycin is currently the drug of choice for MRSA.
19) Expected adverse effects of penicillins EXCEPT
A. Ototoxicity
B. Allergic reactions
C. Diarrhea
D. Intestinal nephritis (I think this is interstitial nephritis)
A. From Katzung: “The penicillins are generally well tolerated…Most of the serious adverse effects are due to hypersensitivity…Oral lesions, fever, interstitial nephritis (an autoimmune reaction to a penicillin-protein complex)…may also occur…Large doses of penicillins give orally may lead to gastrointestinal upset, particularly nausea, vomiting and diarrhea. (12th edition, p. 796.)
Also, ototoxicity is a known ADR of aminoglycosides such as streptomycin.
20) Rina is a 2 day old neonate born to a mother diagnosed with untreated syphilis. The penicillin of choice is:
A. Amoxicillin-clavulanic acid
B. Piperacillin-tazobactam
C. Oxacillin
D. Pen G
D. Penicillin G is the drug of choice for syphilis.
21) Cefuroxime is useful for treatment of infections caused by the following pathogens EXCEPT
A. Hemophilus influenza
B. E. coli
C. S. pneumonia
D. Legionella
D. Cefuroxime is a second-generation cephalosporin.
From Katzung: “In general, they [second-gen cephalosporins] are active against organisms inhibited by first-generation drugs (in pertaining to first generation drugs: these drugs are very active against gram-positive cocci, such as pneumococci, streptococci and staphylococci)…E. coli, K. pneumonia and P. mirabilis are often sensitive…Cefamandole, cefuroxime, cefmetazole, ceforanide, and cefaclor are active against H. influenzae.” Legionella is a gram-negative microorganism, which second-gen cephalosporins have poor activity against.
22) Indications for the use of cotrimoxazole include the following EXCEPT
A. Prophylaxis of Pneumocystic jiroveci pneumonia
B. Treatment of susceptible Burkholderia cepacia sepsis
C. Treatment of Histoplasma
D. Treatment of H. influenzae otitis media
C. Histoplasma are fungi. Treat with either amphotericin B or itraconazole.
23) True of tetracycline EXCEPT
A. Has good activity against intracellular bacteria such as legionella and chlamydia
B. Is safe for long term use in patients less than eight years old and pregnant women
C. Long acting preparations can be given once a day or every 12 hours
D. Side effect include photosensitivity, hepatotoxicity, and SLE
B. From Katzung: “Tetracyclines are readily bound to calcium deposited in newly formed bone or teeth in young children…during pregnancy, it can be deposited in the fetal teeth…Because of these effects, tetracyclines are generally avoided in pregnancy. If the drug is given for long periods to children younger than 8 years, similar changes can result.” (12th edition, p. 812)
24) Erythromycin is used as an alternative drug for penicillin for many indications EXCEPT
A. S. pneumonia pneumonia
B. Mycoplasma pneumonia
C. Rheumatic fever prophylaxis
D. Syphilis
C. From the website of the American Association of
Family Physicians, the macrolides listed under “Primary
Prevention of Rheumatic Fever, for patients allergic to penicillin” are azithromycin, clarithromycin and clindamycin.
25) What is a correct indication for the usage of chloramphenicol?
A. Malaria
B. Typhoid fever
C. Staphylococcal impetigo
D. Otitis media
B. From Medscape: “For sensitive strains, still most widely used antibiotic to treat typhoid fever.”
26) True of ciprofloxacin
A. It is the drug of choice for MRSA
B. It has good activity for S. pneumonia
C. It inhibits topoisomerase II and IV
D. It is active against plasmodium
C. From Katzung: “Quinolones block bacterial DNA synthesis by inhibiting bacterial topoisomerase II (DNA gyrase) and topoisomerase IV.” (12th edition, p. 835)
27) Antimicrobial agents that are avoided during pregnancy are the following EXCEPT
A. Ciprofloxacin
B. Cotrimoxazole
C. Doxycycline
D. Cefixime
D. From Medscape: “Pregnancy category B (may be acceptable. Either animal studies show no risk, but human studies not available or animal studies showed minor risks and human studies done and showed no risk.)”
Ciprofloxacin causes arthopathy, doxycycline deposits in bones and teeth, and cotrimoxazole inhibits folate synthesis.
28) Adverse effects of chloramphenicol include the following EXCEPT A. Gray baby syndrome B. Red man syndrome C. Idiosyncratic aplastic anemia D. Dose-related bone marrow depression
B. From Medscape, grey baby syndrome, aplastic anemia and bone marrow depression are all listed under adverse effects. Red man syndrome (so-called because of the erythematous rash that appears in the face and upper body) is more related to IV-infused vancomycin.
29) The disadvantage of using erythromycin in comparison to newer macrolides for respiratory tract infections is that erythromycin has poor activity for A. S. pneumonia B. Legionella C. H. influenza D. Chlamydia
C. From Katzung: “Erythromycin is active against susceptible strains of gram-positive organisms, especially pneumococci, streptococci, staphylococci, and corynebacteria…Chlamydia trachomatis,
Chlamydia pneumonia are susceptible…H. influenzae is somewhat less susceptible.
Antiparasitic
30) Which statement is FALSE about metronidazole?
A. It is a luminal amoebicide only
B. It has good activity for anaerobic bacteria
C. It is used for the treatment of pseudomembranous colitis
D. It is used as prophylaxis in colorectal surgery
A. From Antiparasitics trans: “Treatment of antibiotic-induced pseudomembranous colitis by C. difficile.”
31) Present first-line treatment of malaria includes the following EXCEPT
A. Artemether-lumefantrine for plasmodium falciparum
B. Chloroquine for plasmodium vivax
C. Primaquine for 14 days for plasmodium vivax
D. Quinine for plasmodium ovale
D. Antiparasitics trans.
32) True about quinine
A. It is an alternative drug for Taenia saginata
B. Therapeutic doses may cause hypoglycemia
C. It may cause SJS
D. It is derived from the bark of the quassia plant
B. Antiparasitics trans. Derived from the bark of the cinchona tree, causes hypoglycemia, sinus arrhythmia, ventricular tachycardia, etc. Mebendazole is used as the alternative drug for T. saginata infections.
33) True about coartem
A. Is a combination of 2 antifolate drugs
B. Is the current drug of choice for plasmodium falciparum
C. Is a tissue schizonticide
D. Is given IV only
B. Co-trimoxazole is the combination of 2 antifolate drugs (sulfamethoxazole and trimethoprim), primaquine is the only tissue schizonticide and coartem can be given orally.
34) True of albendazole EXCEPT
A. Is a narrow spectrum antihelmintic and can only be used to eradicate ascaris
B. Inhibits microtubule synthesis thus impairing glucose uptake of the helminth
C. May induce clearance of the parasite from the GIT several days after intake
D. Is a benzimidazole carbamate
A. From Antiparasitics trans: Broad-spectrum antihelminthic, with activity against Ascaris, Trichuris, hookworm and pinworm infections. It is a benzimidazole carbamate, and as its MOA, inhibits microtubule synthesis, killing parasites slowly but effectively by paralyzing them. This is why it takes days for the parasites to be cleared from the GIT.
Matching type 35) Brugia malayi
C. B. malayi causes filariasis.
36) Taenia saginata
Praziquantel
37) Prophylaxis for malaria
Doxycycline
38) Capillaria philipinensis
Albendazole
39) Echinococcus granulosus
Albendazole
Antifungals
40) True of amphotericin B EXCEPT
A. It is the most potent among all the anti-fungals
B. It is a polyene antifungal
C. It creates pores in the fungal membrane
D. It can cause gynecomastia
D. Antifungals trans. Amphotericin B is a polyene macrolide (others are nystatin and natamycin) whose MOA is interaction with sterols in cell membranes to form channels or pores through the membrane (consequence is leakage of intracellular ions like K+). It is the gold standard and has the broadest spectrum for yeasts, and is reserved for treatment of life-threatening fungal infections.
