REVIEW MICROBIOLOGY from FIRST AID USMLE
REVIEW MICROBIOLOGY from FIRST AID USMLE
1. Bacillus anthracis capsule contains which substance?
Key: D-glutamate
2. Which bacteria lacks a cell wall?
Key: Mycoplasma
3. What is Loeffler’s media used for?
Key: Culturing Corynebacterium diphtheriae
4. Name some obligate aerobes.
Key: Nocardia, Pseudomonas, Mycobacterium tuberculosis, Bacillus
5. Which organism poses a risk to asplenic individuals?
Key: Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis
6. What bacteria secretes IgA protease?
Key: Streptococcus pneumoniae, Haemophilus influenzae type B, Neisseria
7. What is the mode of action of endotoxins?
Key: Induces TNF and IL-1 production
8. What causes rice water diarrhea?
Key: Vibrio cholerae
9. What causes whooping cough?
Key: Bordetella pertussis
10. Which toxin is produced by Clostridium perfringens?
Key: Alpha toxin (lecithinase)
11. What is the causative agent of toxic shock syndrome?
Key: Staphylococcus aureus
12. In which bacterial growth phase are spores formed?
Key: Stationary phase
13. What is the term for bacteria without plasmids?
Key: F-
14. Which organism is catalase positive and coagulase sensitive?
Key: Staphylococcus aureus
15. What causes otitis media in children?
Key: Streptococcus pneumoniae
16. What causes meningitis in babies?
Key: Streptococcus agalactiae
17. What is rusty sputum associated with?
Key: Streptococcus pneumoniae
18. What component of normal flora is Staphylococcus epidermidis?
Key: Skin flora
19. Which normal flora causes dental caries?
Key: Streptococcus mutans
20. Bull neck is seen in which infection, and what is the causative agent?
Key: Diphtheria - Corynebacterium diphtheriae
21. Which toxins of Clostridium botulinum lead to floppy baby syndrome?
Key: Botulinum toxins
22. Sulfur granules in sinus tracts are associated with which organism?
Key: Actinomyces israelii
23. What is the prophylactic treatment for Mycobacterium avium intracellulare?
Key: Azithromycin
24. What is another name for Hansen’s disease?
Key: Leprosy
25. Which drug is used for prophylaxis in Haemophilus influenzae?
Key: Rifampin
26. How is Legionella pneumonia clinically detected?
Key: Presence of antigen in urine
27. Blue-green pigment is produced by the toxins of which bacterium?
Key: Pseudomonas aeruginosa
28. What is the most common serotype causing hemolytic uremic syndrome?
Key: O157:H7
29. What causes red currant jelly sputum?
Key: Klebsiella
30. What causes mesenteric adenitis?
Key: Yersinia enterocolitica
31. What are the bacteria with a question mark-shaped appearance?
Key: Leptospira interrogans
32. Abdominal rose spots, fever, and headache are features of which condition?
Key: Salmonella typhi infection (Typhoid fever)
33. What is the bulls-eye rash associated with?
Key: Lyme disease
34. Saddle nose and Hutchinson teeth are features of which disease?
Key: Congenital syphilis
35. What is the causative agent of Q fever?
Key: Coxiella burnetii
36. Clue cells and a fishy-smelling discharge are associated with which infection?
Key: Gardnerella vaginalis (Bacterial vaginosis)
37. What assay is used in the diagnosis of rickettsial infections?
Key: Latex agglutination
38. Palm and sole rash is seen in infections caused by which viruses?
Key: Coxsackievirus A, Rocky Mountain spotted fever, and syphilis
39. What causes Reiter’s syndrome?
Key: Chlamydia trachomatis
40. Which bacterium is the only one having cholesterol?
Key: Mycoplasma pneumonia
41. What is the term for budding yeast with a captain wheel formation?
Key: Paracoccidioidomycosis
42. What causes a spaghetti and meatball appearance in a KOH prep?
Key: Tinea versicolor
43. Which fungus has septate hyphae branching at acute angles?
Key: Aspergillus fumigatus
44. Which fungal disease is most commonly seen in DKA and leukemic patients?
Key: Mucor and Rhizopus
45. What is Rose Gardener disease associated with?
Key: Sporothrix schenckii
46. Severe diarrhea in AIDS is often caused by which parasite?
Key: Cryptosporidium
47. What is the classic triad associated with Toxoplasma gondii?
Key: Chorioretinitis, hydrocephalus, and intracranial calcification
48. How does Naegleria fowleri enter the brain?
Key: Cribriform plate
49. Which disease is caused by the kissing bug?
Key: Chagas disease
50. What is the treatment for Leishmania donovani?
Key: Sodium stibogluconate
51. In Plasmodium malaria, what is the duration of the cycle in hours?
Key: 72 hours
52. What is the Scotch tape test used for?
Key: Enterobius vermicularis (pinworm)
53. Which organism, carried by female Anopheles, causes blockage of lymphatic vessels?
Key: Wuchereria bancrofti
54. What causes a Swiss cheese appearance in the brain?
Key: Neurocysticercosis - Taenia solium
55. River blindness is caused by which parasite?
Key: Onchocerca volvulus
56. What disease of the bladder is caused by Schistosoma hematobium?
Key: Squamous cell carcinoma of the bladder
57. Which agent causes pipestem cirrhosis?
Key: Schistosoma mansoni
58. What do surgeons inject to kill daughter cells of a hydatid cyst?
Key: Ethanol
59. Which organism is found in macrophages containing amastigotes?
Key: Leishmania donovani
60. Cholangiocarcinoma is associated with which organism?
Key: Clonorchis sinensis
61. What drugs are used against Staphylococcus aureus?
Key: Methicillin, Nafcillin
62. Name a beta-lactamase inhibitor.
Key: Clavulanic acid, Sulbactam, Tazobactam
63. What causes red man syndrome?
Key: Vancomycin
64. What is the drug of choice for meningitis and gonorrhea?
Key: Ceftriaxone
65. Imipenem is always administered with what?
Key: Cilastatin
66. What is the main side effect of aminoglycosides?
Key: Nephrotoxicity, Ototoxicity, Teratogenicity
67. Tetracycline must not be taken with what?
Key: Milk, antacids, and iron-containing preparations
68. What is the drug of choice for atypical pneumonia?
Key: Macrolides
69. Gray baby syndrome is a side effect of which drug?
Key: Chloramphenicol
70. Trimethoprim inhibits bacterial what?
Key: Dihydrofolate reductase
71. What is the only agent used as solo prophylaxis against TB?
Key: Isoniazid
72. Hyperuricemia is a side effect of which anti-TB drug?
Key: Pyrazinamide
73. What is the prophylaxis for recurrent UTI?
Key: Trimethoprim-sulfamethoxazole
74. Which anti-TB drug induces the P-450 system?
Key: Rifampin
75. Soap bubble lesions in the brain are seen in which infection?
Key: Cryptococcus neoformans
76. Oral thrush in an immunocompromised patient is caused by?
Key: Candida albicans
77. Flask-shaped ulcer on histology is seen in infection by which organism?
Key: Entamoeba histolytica
78. African sleeping sickness is transmitted by?
Key: Tsetse fly
79. What does the chlamydial cell wall lack?
Key: Muramic acid
80. Condylomata lata is seen in which syphilis stage?
Key: Secondary
81. What causes Lyme disease?
Key: Borrelia burgdorferi
82. What is a common antecedent of Guillain-Barré syndrome?
Key: Campylobacter jejuni
83. Tumbling motility is characteristic of which bacterium?
Key: Listeria monocytogenes
84. What temperature and duration must be used to autoclave and kill spores by steaming?
Key: 121°C for 15 minutes
85. Which bacteria exhibit a club shape?
Key: Corynebacterium diphtheriae
86. What does tetanospasmin prevent the release of?
Key: Inhibitory neurotransmitters in the spinal cord
87. Which protein is involved in opsonization and phagocytosis?
Key: Protein A
88. Lowenstein-Jensen agar medium is used for what organism?
Key: Mycobacterium tuberculosis
89. Silver stain is used for which microorganisms?
Key: Legionella and fungi
90. What is the treatment for Chagas disease?
Key: Nifurtimox
91. What is the term for the exchange of genes between two chromosomes by crossing over within regions of significant base sequence homology?
Key: Recombination
92. Except for parvovirus, are all DNA viruses double-stranded or single-stranded?
Key: Double-stranded
93. Except for retrovirus, are all viruses haploid or diploid?
Key: Haploid
94. What causes slapped cheeks syndrome?
Key: Parvovirus B19
95. Owls eyes inclusions are seen in infections with which virus?
Key: Cytomegalovirus (CMV)
96. Atypical lymphocytes are seen in infections with which virus?
Key: Epstein-Barr virus (EBV)
97. What is the number one cause of fatal diarrhea in children?
Key: Rotavirus
98. In picornaviruses, which are not retroviruses?
Key: Rhinoviruses
99. What transmits the yellow fever virus?
Key: Aedes mosquito
100. What is the largest DNA virus?
Key: Poxvirus
101. From where do herpes viruses acquire their envelope?
Key: Nuclear membrane
102. Name other viruses in the Paramyxovirus family.
Key: Parainfluenza, RSV, and rubella
103. What do Koplik spots indicate?
Key: Measles virus
104. What are Negri bodies characteristic of?
Key: Rabies virus
105. Anti-HBcAg is positive during which period?
Key: Window period
106. What does gp41 show in HIV?
Key: Fusion and entry
107. Name the stages of HIV infection.
Key: Flu-like, Feeling fine, Falling count, Final crisis
108. What causes bacillary angiomatosis?
Key: Bartonella henselae
109. What is the agent causing ring-enhancing lesions in HIV patients?
Key: Toxoplasma gondii
110. What is the agent causing retinitis in HIV?
Key: CMV (Cytomegalovirus)
111. What is the normal flora of the skin?
Key: Staphylococcus epidermidis
112. Which toxin is found in canned food?
Key: Clostridium botulinum
113. What toxins are present in reheated rice?
Key: Staphylococcus aureus
114. In cystic fibrosis patients, what is the most common cause of pneumonia?
Key: Pseudomonas
115. What is the agent causing travelers’ diarrhea?
Key: Enterotoxigenic E. Coli
116. What causes nosocomial infections?
Key: Staphylococcus aureus
117. What is the most common cause of septic arthritis?
Key: Neisseria gonorrhea
118. What is vertebral tuberculosis also called?
Key: Pott’s disease
119. Why do UTIs most commonly occur in women than men?
Key: Female anatomy with a shorter urethra
120. What is the second leading cause of community-acquired UTI?
Key: Staphylococcus saprophyticus
121. How is Toxoplasma gondii transmitted?
Key: Cat feces
122. What is the classic triad of rubella?
Key: PDA, cataract, and deafness
123. What causes a sandpaper-like rash with a sore throat?
Key: Scarlet fever
124. Which virus causes a vesicular rash that begins on the trunk, spreads to the face and extremities, with lesions of different ages?
Key: Varicella-zoster virus (VZV)
125. What causes a painful genital ulcer with inguinal lymphadenopathy?
Key: Hemophilus ducreyi
126. What organism is associated with genital warts?
Key: HPV 6 and 11
127. Violin string adhesion of the parietal peritoneum to the liver is seen in which syndrome?
Key: Fitz-Hugh-Curtis syndrome
128. What is the most common cause of nosocomial wound infections?
Key: Staphylococcus aureus
129. Water aerosol is a risk factor for which pathogen?
Key: Legionella
130. Pseudomembranous colitis is caused by which bacterium?
Key: Corynebacterium diphtheriae
131. Cherry red epiglottis in children is seen in infection with which pathogen?
Key: Haemophilus influenzae type B
132. What causes Whipple disease?
Key: Tropheryma whipplei
133. Bilateral Bell’s palsy is seen in infection with which pathogen?
Key: Lyme disease
134. What is the mechanism of action of Amphotericin?
Key: Forms membrane pores
135. What is the drug of choice for cryptococcal meningitis in AIDS patients?
Key: Fluconazole
136. What is the drug of choice for invasive aspergillosis?
Key: Caspofungin
137. What is the treatment for Trypanosoma brucei?
Key: Melarsoprol
138. What is the prophylaxis and treatment for influenza A virus?
Key: Amantadine
139. What is the second-line drug for CMV retinitis in immunocompromised patients?
Key: Foscarnet
140. What toxicity is caused by interferon?
Key: Neutropenia
141. What do all protease inhibitors end in?
Key: Navir
142. Which drug is used for prophylaxis and fetal transmission during pregnancy in HIV?
Key: Zidovudine
143. Why are fluoroquinolones contraindicated during pregnancy?
Key: Cartilage damage
144. Which class of drugs must be phosphorylated by thymidine kinase to be active?
Key: Nucleotide reverse transcriptase inhibitors
145. What is the side effect of megaloblastic anemia associated with which anti-HIV drug?
Key: Zidovudine
146. Terbinafine inhibits which fungal enzyme?
Key: Squalene epoxidase
147. What is the initial empirical therapy for community-acquired pneumonia?
Key: Fluoroquinolones
148. What is the HIV prophylaxis for Pneumocystis pneumonia?
Key: TMP-SMX
149. Red-green color blindness is a side effect of which anti-TB drug?
Key: Ethambutol
150. Which pathogen is associated with dog or cat bites?
Key: Pasteurella multocida
151. Name the top bugs causing pelvic inflammatory disease.
Key: Chlamydia trachomatis, Neisseria gonorrhoeae
152. What is the third leading cause of UTI?
Key: Klebsiella pneumoniae
153. Name three agents, in descending order, causing meningitis in newborns.
Key: Group B Streptococcus, E. coli, Listeria
154. What is the most common pathogen causing osteomyelitis?
Key: Staphylococcus aureus
155. Name viruses causing watery diarrhea.
Key: Rota, adeno, and Norwalk viruses
156. What causes pseudoappendicitis?
Key: Yersinia enterocolitica
157. Kaposi’s sarcoma is associated with which herpes virus?
Key: HHV-8
158. In HIV, attachment to the host cell is done by?
Key: gp120
159. How are hepatitis viruses transmitted via the fecal-oral route?
Key: HAV, HEV
160. What virus has a bullet-shaped capsid?
Key: Rhabdovirus
161. What are the symptoms of mumps?
Key: Parotitis, orchitis, and aseptic meningitis
162. What are the 3 Cs of measles?
Key: Coryza, cough, and conjunctivitis
163. Which protein in paramyxovirus causes respiratory epithelial involvement?
Key: F protein
164. Which viruses are included in the Picornavirus family?
Key: Polio, echo, rhino, coxsackie, and HAV
165. Post-cervical lymphadenopathy is associated with which virus?
Key: EBV (Epstein-Barr virus)
166. What causes flesh-colored dome lesions with a central dimple?
Key: Molluscum contagiosum
167. All DNA viruses replicate in the nucleus except for which one?
Key: Poxvirus
168. All RNA viruses replicate in the cytoplasm except for which ones?
Key: Influenza and retroviruses
169. Which anti-HIV drug causes hypercholesterolemia?
Key: Raltegravir
170. Which drug causes a metallic taste?
Key: Metronidazole
171. What is the toxicity of isoniazid?
Key: Neurotoxicity and hepatotoxicity
172. What does fluoroquinolone damage?
Key: Cartilage
173. In lung abscess, what is the drug of choice?
Key: Clindamycin
174. What pathogen is usually associated with respiratory therapeutic equipment?
Key: Pseudomonas aeruginosa
175. Healthcare providers are at risk of which infection?
Key: HBV (Hepatitis B)
176. What is a risk factor for salpingitis?
Key: Ectopic pregnancy
177. Strawberry-colored mucosa of the vagina is caused by which pathogen?
Key: Trichomonas vaginalis
178. Osteomyelitis in diabetes and IV drug abusers is caused by which pathogen?
Key: Pseudomonas aeruginosa
179. What is the normal flora in the vagina?
Key: Lactobacillus
180. What is the acquired prion disease called?
Key: Kuru
181. What pathogen causes invasive aspergillosis?
Key: Aspergillus fumigatus
182. What is the normal flora of the oropharynx?
Key: Streptococci viridans
183. India ink stain reveals yeast with a mariner-based budding and a large capsule. Name the pathogen.
Key: Cryptococcus neoformans
184. During the latent phase of the course of HIV infection, where does the virus replicate?
Key: Lymph nodes
185. Attachment of HIV virus is facilitated by which glycoprotein?
Key: gp120
186. What is the best test to detect active hepatitis A?
Key: Anti-HAVAb (IgM)
187. In measles, Negri bodies are commonly found in which cells of the cerebellum?
Key: Purkinje cells
188. What virus causes SARS?
Key: Coronavirus
189. EBV (infectious mononucleosis) infects which cells?
Key: B cells
190. What are the other names for slapped cheek syndrome?
Key: Fifth disease, erythema infectiosum
191. Eosinophilic pneumonia is caused by which nematode?
Key: Ascaris lumbricoides
192. What is the treatment for river blindness?
Key: Ivermectin
193. What causes cerebral malaria?
Key: Plasmodium falciparum
194. Mucor causes which lobe abscess?
Key: Frontal lobe
195. Post-TB cavities are usually formed by which fungal infection?
Key: Aspergillus fumigatus
196. What causes pruritic lesions with central clearing resembling a ring?
Key: Dermatophytes
197. Which types of Chlamydia trachomatis cause lymphogranuloma venereum?
Key: L1, L2, and L3
198. What type of rash starts centrally and spreads outward without involving palms and soles?
Key: Typhus rash
199. What causes plague?
Key: Yersinia pestis
200. What is the most common serotype of E. coli?
Key: O157:H7
Microbiological Insights on Pathogens
Bacillus anthracis: The capsule is composed of D-glutamate, providing protection against phagocytosis.
Mycoplasma: Notable for its lack of a cell wall, making it resistant to certain antibiotics.
Corynebacterium diphtheriae: Cultured using Loeffler’s media, associated with diphtheria.
Obligate Aerobes: Include Nocardia, Pseudomonas, and Mycobacterium tuberculosis, requiring oxygen for survival.
Asplenic Individuals: At risk from infections with Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.
Endotoxins: Act by inducing the production of TNF and IL-1, leading to fever and shock.
Vibrio cholerae: Known to cause rice water diarrhea due to cholera toxin.
Staphylococcus aureus: Linked to toxic shock syndrome and produces various enterotoxins.
Coxsackievirus A: Associated with viral myocarditis and hand, foot, and mouth disease.
Leptospira interrogans: Characterized by its question mark-shaped appearance, linked to water contamination.