Micro - Para FINAL

(1)

MICROBIOLOGY & PARASITOLOGY

1. Many of this type of bacteria do not possess superoxide dismutase and catalase A. obligate aerobes

B. obligate anaerobes C. facultative anaerobes D. microaerophiles

p. 66

2. It is the period when the bacterium is assessing the nutrients present in medium; the bacterium does not divide but there is an intense metabolic activity. The phase of bacterial growth is A. Lag B. Log C. Stationary D. Decline p. 53

3. Which the best to sterilize scissors and other sharps? A. Glutaraldehyde

B. Formaldehyde C. Iodophor D. Phenol

p. 60

4. These are groups of genes that are clustered together in the DNA of some bacterial species and which may enable them to invade a host

A. Pathogenicity island B. Episomes

C. Transposons D. Replicons

p. 98

5. Which is true about the bacterial chromosome? A. Contains histones that stabilize the DNA

B. Composed of a single pair of homologous chromosomes

C. Replicates in a very different manner from that of eukaryotic chromosomes D. Contain single copy of each gene

p. 99

6. A non-encapsulated strain of Hemophilus influenzae acquires the gene for capsule production from a DNA extract of another encapsulated strain. The event that has occurred is A. Transformation B. Conjugation C. Transduction D. Transcription p. 106

(2)

7. What is the substance primarily responsible for the structural integrity of the bacterial cell wall and is susceptible to lysozyme?

A. Cytoplasmic membrane B. Teichoic acid

C. Peptidoglycan D. Lipopolysaccharide

p. 22

8. A hospitalized patient with dysuria and suprapubic pain is treated with ciprofloxacin. What is the mechanism of action of this antibiotic?

A. It inhibits DNA-dependent RNA polymerase

B. It inhibits protein synthesis by binding to the 30S ribosomal subunit C. It inhibits protein subunits by binding to the 50S ribosomal subunit D. It inhibits topoisomerase II (DNA gyrase)

p. 164

9. Which bacterial structure may carry gene for antibiotic resistance? A. Mesosome

B. Periplasm C. Plasmid

D. Outer membrane p. 98

10. What is the predominant indigenous flora of the colon?

A. Anaerobic, gram-negative, non-spore-forming bacteria B. Anaerobic, gram-positive, non-spore-forming bacteria C. Aerobic, gram-negative, non-spore-forming bacteria D. Aerobic, gram-positive, spore-forming bacteria

p. 199

11. Which of the following is the true regarding the bacterial cell?

A. He motility of bacteria is due to flagella, axial filaments or cilia

B. The ability to colonize cell surfaces is dependent on toxic production

C. The ability to survive in soil for a long period of time is dependent on the production of endospores

D. It has the same ribosomes as that of a eukaryotic cells p. 35

12. Which of the following is the counterpart of mitochondria in a bacterial cell? A. Cell wall

B. Endospores C. Ribosomes D. Cell membrane

p. 17

13. Which of the following agents possess either DNA or RNA? A. Viruses

B. Prions C. Bacteria D. Fungi

(3)

14. Most pathogenic microorganism grow best at the temperature range of about _____. A. 15-20ºC B. 30-37ºC C. 50-60ºC D. 80-100ºC p. 65

15. A 22-year-old woman came in due to meningococcemia. Few hours after the admission, the patient experienced disseminated intravascular coagulation (DIC). The patient shock was due to what component of the causative agent?

A. Cell wall B. Capsule

C. Lipopolysaccharide D. Endospores

pp. 155-156

16. Which one of the following antimicrobial agents acts on microorganisms by inhibiting nucleic acid synthesis?

A. Streptomycin B. Cefalexin C. Ciprofloxacin D. Erythromycin

p. 189

17. A newborn was diagnosed with neonatal meningitis. The causative agent was found out to be isolated in the vagina of the mother. Which one of the following microorganisms can be a part of the normal vaginal flora of the mother and can cause neonatal

meningitis? A. Mycoplasma pneumoniae B. Staphylococcus aureus C. Escherichia coli D. Streptococcus agalactiae p. 199

18. Which of the following is the “C3 activation unit” in the classical complement pathway? A. C1q

B. C3

C. C4b, C2a

D. C5, C6, C7, C8 and C9 p. 136

19. The classic pathway of the complement system is activated when__

A. The Fab portion of IgM binds to the C1s of the complement pathway B. The Fc portion of IgE binds to the C1q of the complement pathway

C. The hypervariable regions of the heavy and light chains binds to the membrane of the bacterial cell

(4)

20. Antigen-presenting cells that activate helper T cell must express which one of the following on their surfaces?

A. IgE

B. Gamma interferon C. Class I MHC antigens D. Class II MHC antigens

p. 139

21. Increased susceptibility with Hepatitis virus and Candida albicans would be expected with a deficiency of which of the following cells?

A. PMN

B. Eosinophils C. B cells D. T cells

p. 138

22. In Type I hypersensitivity, the predominant antibody that is elicited is: A. IgA

B. IgE C. IgG D. IgM

p. 140

23. Contact dermatitis is an example of: A. IgE mediated

B. Complement mediated C. IgG mediated

D. Cell mediated p. 141

24. This immunoglobulin is important in preventing diarrhea in the newborn A. IgA

B. IgM C. IgE D. IgD

p. 129

25. Main component in secondary response. A. IgA

B. IgM C. IgG D. IgD

p. 135

26. At birth, the main source of Hematopoetic Stem Cell is the A. Liver

B. Spleen

C. Bone Marrow D. Thymus

(5)

27. Which method will you see to detect antigens directly from tissue? A. ELISA B. Ouchterlony technic C. Immunofluorescence D. Complement fixation p. 142

28. Which is true about humoral immunity and antibodies? A. Antibodies found on the surface of B cells are IgA B. IgG has two bindings sites for an antigen

C. IgM is the main protection of the newborn up to 6 (six) months D. The Fab region of IgE binds to mast cell receptor

p. 128

29. Which of the following complement cascade does not involve C3b? A. C5 convertase of the alternative pathway

B. C5 convertase of the classic pathway

C. C3 convertase of the alternative pathway D. C3 convertase of the classic pathway

p. 136

30. Which of the following cells is a part of the innate immune response? A. B-lymphocytes

B. T-helper lymphocytes C. T-cytotoxic lymphocytes D. Macrophages

p. 123

31. Which of the following is LEAST associated with Enterohemorrahgic E. coli? A. fermentation of sorbitol

B. strain 0157:H7

C. undercooked hamburgers D. hemolytic-uremic syndrome

p. 253

32. Which of the following is true about cholera and its causative agent?

A. A secretory diarrhea due to increases in cGMP in the intestinal cells B. The stool is described as ‘rice water-like’

C. The causative agent is non-motile, nonfermentative D. Grows poorly in medium with alkaline pH

p. 271

33. The appearance of moistpale papules or condylomas in the anogenital area is characteristic of

A. Primary syphilis B. Secondary syphilis C. Tertiary syphilis D. T. pallidum

(6)

34. A 4-year old Asian child develops an infection with Chlamydia trachomatis. How does infection with this organism cause blindness?

A. Retinal detachment B. Cataract formation

C. Hemorrhage of the anterior chamber D. Scarring of the cornea

p.360

35. Which is associated with atherosclerosis? A. K. pneumoniae

B. C. trachomatis C. S. pyogenes D. C. pneumoniae

p.364

36. Which of the following is LEAST effective against M. pneumoniae infection? A. Erythromycin

B. Tetracycline C. Kanamycin D. Vancomycin

p. 345

37. The only disease that can be diagnosed by demonstration of spirochetes in peripheral blood smear A. Relapsing fever B. Leptopirosis C. Pinta D. Lyme disease p. 335

38. Which of the following is LEAST associated with Helicopter pylori? A. It requires at least 2% NaCl for growth (halophilic)

B. It requires increased carbon dioxide tension and decreased oxygen tension C. It is sensitive to the acidity of the gastric juice

D. Most commonly diagnosed by the demonstration of urease production p.275

39. In which type of diarrhea is the use of antibiotics not recommended? A. Salmonellosis

B. Campylobacter infection C. Cholera

D. Shigellosis p. 259

(7)

40. Which causes urinary tract infection characterized by alkaline urine and formation of urinary calculi? A. Shigella dysenteriae B. Escherichia coli C. Proteus mirabilis D. Enterobacter cloacae p. 254

41. Which is LEAST acceptable as specimen for the diagnosis of anaerobic infection A. Transtracheal aspirate

B. Suprapubic aspirate C. Vaginal swab

D. Sample of tissue from infected site p. 309

42. Which of the following microorganisms takes up the color of Crystal violet upon properly performed Gram staining?

A. Neisseria gonorrheae B. Clostridium perfringens C. Escherichia coli

D. Pseudomonas sp. p. 208

43. Which of the following is a Toxoid vaccine? A. Pnuemococcal

B. Measles C. Varicella D. Diphtheria

p. 215

44. The most infectious stage in pertussis is: A. Catarrhal stage

B. Prodomal stage C. Paroxysmal stage D. Convalescent stage

p. 283

45. Regarded as a TB marker in the diagnosis of tuberculous effusion: A. Gamma interferon

B. AFB smear

C. Caseation necrosis D. PPD positivity

p. 407

46. Presence of immunity to C. diphtheriae is indicated by: A. Positive elek test

B. Negative elek test C. Positive schick test D. Negatice schick test

(8)

47. Which of the following is MOST likely acquired from caves? A. Blastomycosis B. Histoplasmosis C. Coccidioidomycosis D. Paracoccidioidomycosis p. 642

48. Asteroid bodies are seen tissue infected with A. P. verrucosa

B. P. boydii C. S. schenckii D. L. loboi

p. 634

49. The agents of chromomycosis are seen in infected tissues as A. Intracellular yeast

B. Granules

C. Sclerotic bodies D. Cigar-shaped bodies

p. 635

50. Which of the following is NOT dimorphic? A. P. boydii

B. H. capsulatum C. S. schenckii D. C. immitis

p. 636

51. The agent of blastomycosis are seen in infected tissues as A. Intracellular yeast

B. Single budding yeast C. Multiple budding yeast D. Cigar-shaped bodies

p. 642

52. The physician closely monitored the patient’s serum creatinine and ion levels. The patient is taking certain anti-fungal drug. What possible antifungal agent may affect the renal function of this patient?

A. Ketoconazole B. Terbinafine C. Griseofulvin D. Amphotericin B

p. 653

53. The primary site of echovirus multiplication in the human host is A. The muscular system

B. The alimentary tract C. The anterior horn cells D. The respiratory system

(9)

54. Which of the following properties of polioviruses is not shared by rhinovirus? A. Icosahedral symmetry

B. Resistance to lipid solvents C. Naked virus

D. Stability at acid pH (pH3.0) p. 489

55. Segmented, double-stranded RNA genome that is a common cause of viral gastroenteritis? A. Astrovirus B. Norwalk virus C. Calicivirus D. Rotavirus pp. 505-507

56. Diagnostic of Congenital rubella is the demonstration of rubella antibodies like: A. Maternal IgM

B. Neonatal IgM C. Neonatal IgA D. Maternal IgA

p. 568

57. A viral cause of nephropathy in immunocompromised patient is A. Human papillomavirus, all types

B. Human papillomavirus, low-risk types C. Hepatitis C

D. Polyomavirus BK pp. 598-599

58. Which of the following individuals may be at increased risk of acquiring and HIV infection?

A. A pregnant mother with a seafarers husband B. A secretary at an AIDS institute

C. A doctor with a colleague that is HIV positive

D. A male celebrity who has multiple sexual partner including a prostitute pp. 616-617

59. Type of papillomavirus that is commonly associated with cervical carcinoma A. Type 1

B. Type 6 C. Type 9 D. Type 18

p. 601

60. Progressive Multifocal leukuencepalopathy is associated with a virus that is described as __.

A. ssDNA, icosahedral, naked B. dsDNA, helical, enveloped C. dsDNA, icosahedral, naked

(10)

61. Which of the following virus that can enter a skin through abrasions? A. Adenovirus B. Polyomavirus C. Papillomavirus D. Rhinovirus p. 599

62. A 6-year old child had recently had fifth disease. Her 43-year old mother subsequently developed a rash and arthalgia. Which one of the following best describes the causative agent?

A. It has the same size as poxvirus B. It has a helical symmetry

C. Inactivated by ether

D. A single-stranded DNA genome pp. 414-416

63. HIV is a retrovirus. A retrovirus is a A. Cause tumors in mouse B. Contain a DNA genome

C. Cause rapidly progressive neurological disease D. Multiplies in the nucleus

p. 605

64. Most common cause of post transfusion hepatitis A. HAV

B. HBV C. HCV D. HDV p. 466

65. Site of latent infections is at the sacral ganglia: A. HSV 1

B. HSV 2 C. EBV D. CMV

pp. 433-434

66. Which of the following viruses can establish a latent infection? A. Poxviruses

B. Rubella viruses C. Herpesviruses D. Coronaviruses

p. 371

67. A 23-year-old medical student experienced fever, sore throat, and lymphadenopathy. These were accompanied by lymphocytosis and atypical cells in the blood smear. True statement regarding the causative agent

A. the major target cell of the virus is the T lymphocyte B. the agent multiplies in the cytoplasm

C. it can be transmitted thru direct contact with the lesion D. it possess a double-stranded DNA genome

(11)

68. The following hepatitis B marker is indicative of active viral replication A. HBsAg B. HBeAg C. Anti- HBs D. Anti- HBe p. 468

69. The habitat is the large intestine. A. Entamoeba gingivalis B. Entamoeba histolytica C. Giardia lamblia

D. Naegleria fowleri p. 104

70. The infective stage of Entamoeba histolytica to man has A. Pseudopodia

B. Ingested red blood cells C. Bull’s eye karyosome D. Pointed chromatoidal bodies

pp. 103-104

71. The most commonly involved area in Amoebiasis is the A. Brain

B. Cecum C. Liver

D. Recto-sigmoid region pp. 108-109

72. There is no increase in the number of nuclei of A. Balantidium coli

B. Entamoeba coli C. Entamoeba D. Giardia lamblia

p. 215

73. Tissue invasion is relatively slow and tends to stimulate granuloma formation A. Acanthamoeba castellanii

B. Balantidium coli C. Entamoeba histolytica D. Naegleria fowleri

p. 142

74. Mosquito vector of Malaria in the Philippines is A. Aedes aegypti

B. Anopheles flavirostris C. Culex quinquefasciatus D. Mansonia annulata

(12)

75. There is secondary exo-erythrocytic phase in A. Benign tertian malaria

B. Malignant tertian malaria C. Quartan malaria

D. Sub-tertian malaria p. 177

76. The duration of the Erythrocytic-Schizogonic Cycle is 72 hours. A. A. Benign tertian malaria

B. Malignant tertian malaria C. Quartan malaria

D. Sub-tertian malaria pp. 184-191

77. The gametocytes of the organism are described as banana or crescent-shaped. A. Plasmodium falciparum

B. Plasmodium malariae C. Plasmodium ovale D. Plasmodium vivax

pp. 188-190

78. Produces rectal prolapse in heavy infection especially among children A. Capillaria philippinensis

B. Trichinella spiralis C. Trchuris trichiura D. Ascaris lumbricoides

p. 243

79. Bachman intradermal test & Xenodiagnosis are use for the diagnosis of infection cause by A. Capillaria philippinensis B. Trichinella spiralis C. Trchuris trichiura D. Ascaris lumbricoides p. 239

80. The most common cause of Greeping Eruption or Cutaneous Larva Migran A. Ancytostoma braziliense

B. Enterobius vermicularis C. Strongyloides stercoralis D. toxocara canis

p. 281

81. The most common cause of Visceral Larva Migran A. Ancylostoma braziliense

B. Enterobius vermicularis C. Strngyloides stercolaris D. Toxocara canis

(13)

82. Produces autoinfection to man A. Ancylostoma duodenale B. Ascaris lumbricoides C. Necator americanus D. Strongyloides stercolaris p. 256

83. What parasite produces Iron deficiency anemia to man? A. Ascaris lumbricoides

B. Necator americanus C. Strongyloides stercolaris D. Trichuris trichiura

p. 284

84. Associated with Noctrunal Pruritus Ani. A. Ascaris lumbricoides

B. Enterobius vermicularis C. Necator americanus D. Trichuris trichiura

p. 304

85. Graham Scotch tape technique is used for the diagnosis of the infection caused by A. A. Ascaris lumbricoides

B. Enterobius vermicularis C. Necator americanus D. Trichuris trichiura

p. 305

86. What parasite sucks and ingests blood? A. Ancylostoma duodenale B. Ascaris lumbricoides C. Enterobius vermicularis D. Trichuris trichiura

p. 284

87. What parasite shows Tramway sign in the X-ray? A. Ascaris lumbricoides

B. Enterobius vermicularis C. Necator americanus D. Trichuris trichiura

p. 317

88. The infective stage of the parasite is found in crabs or crayfishes A. Clonorchis sinensis

B. Echinostoma ilocanum C. Fasciola hepatica

D. Paragonimus westermani p. 465

(14)

89. What parasite is associated with neoplasm of the biliary duct or cancer of the liver? A. Clonorchis sinensis B. Fasciola hepatica C. Opisthorchis felineus D. Paragonimus westermani p. 477

90. What parasite produces infection that stimulates tuberculosis? A. Clonorchis sinensis

B. Fasciola hepatica C. Opisthorchis felineus

D. Paragonimus westermani pp. 467-468

91. What is the infective stage of Schistosoma to man? A. Cercariae

B. Embryonated egg C. Metacerciae D. Miracidium

p. 417

92. Molluscan host of Schistosoma in the Philippines is A. Australorbis mystax

B. Biomphalaria alexandrina C. Coxiella burnetii

D. Oncomelania quadrasi p. 416

93. Laboratory procedure that makes use of the egg in the test is A. CFT

B. CHR C. COPT D. Casoni test

p. 770

94. The infective of Diphyllobothrium latum to man to produce adult infection is the A. Cysticercoid larva

B. Cysticercus larva C. Procercoid larva D. Sparganum larva

p. 497

95. Produces Ocular cysticercosis to man A. Dipylidium caninum

B. Taenia saginata C. Taenia solium D. Hymenolepis nana

(15)

96. Lateral uterine branches in gravid proglottid are counted for diagnosis of infection cause by A. Diphyllobothrium latum B. Dipylidium caninum C. Hymenolepsis nana D. Teania saginata p. 522

97. Taenia saginata is associated with A. Cat

B. Cattle C. Dog D. Pig

p. 521

98. Ultrasound and MRI usually help in the diagnosis of the infection cause by A. Dipylidium caninum

B. Echinococcus granulosus C. Hymenolepis diminuta D. Hymenolepis nan

p. 532

99. This organism produces a blue-green pigment and therefore produces a characteristic blue-green pus.

A. Staph aureus

B. Pseudomonas aeruginosa C. Aspergillus fumigatus

D. Strep. pyogenes

Pseudomonas aeruginosa produce pyocyanin pigment w/c is blue green in color and also has antibiotic-like characteristics against some bacteria Reference: Zinsser p. 577

100. Each of the following statements concerning the surface structures of bacteria is correct EXCEPT:

A. Pili mediate the interaction of bacteria with mucosal epithelium B. Polysaccharides capsules retard phagocytosis

C. Both gram negative rods and cocci have polysaccharides (endotoxin in their cell wall)

D. Bacterial flagella are not antigenic in humans

Bacterial flagella are made of proteins and are useful in distinguishing serovars or variation of gram negative bacteria such as E. coli H. antigens Sal. H .antigens.

Reference: Zinsser. Chapter 3

101. The most common site of asymptomatic gonococcal infection in women is the: A. Vagina

B. Myometrium C. Urethra D. Endocervix

(16)

The columnar epithelial cells here are the ones that are being infected by N. gonorrhea.(A). Vaginal walls composed of stratified squamous epithelial cells which are not colonized. (B) and (C) are not affected.

Reference: Zinsser p. 456

102. The following etiologic agents are known to cause diarrhea EXCEPT: A. Clostridium perfringens

B. Rotavirus C. V. cholera

D. Proteus vulgaris

Protues vulgaris produce urinary tract infection. C. clostridium perfringens diarrhea thru it’s invasiveness so blood and mucus is (+) V. cholera-produced diarrhea by virtue of enterotoxin. Rotavirus most common cause of viral gastroenteritis in small children.

103. A 20 year old male developed a carbuncle with surrounding cellulitis. Gram stain revealed gram positive cocci, catalase and coagulase positive. Which of the following antibiotics is initially appropriate for this patient?

A. Vancomycin B. Cloxacillin C. Cefriaxone D. Penicillin

90% of S. aureus strains are resistant to penicillin because pf production of plasmid-derived lactamses. Such organisms can be treated with β-lactamase-resistant penicillin such as cloxacillin or dicloxacillin oxacillin. Oxacillin and Nafcillin have unpredictable absorption by oral route, thus is not recommended

104. Which of the following features help distinguish group A streptococcus from other streptococcal species?

A. Bacitracin susceptibility B. Bile solubility

C. Optochin sensitivity

D. Growth inhibition in 6.5 % NaCl

Group A streptococcus is a β-hemolytic streptococcus and can usually be distinguished from the other β-hemolytics by its bacitracin susceptibility or by precipitation with specific anti sera (against its "Lancefrield antigen"). Bile solubility test and optochin test distinguishes the L-hemolytic streptococci, S. pneumoniae is bile soluble and optochin sensitive. Among the hemolytic streptococci, S. viridans growth is inhibited by 6.5% NaCl while Enterococcus species grows in 6.5% NaCl.

105. Which of the following Clostridia cause gangrene? A. Clostridium tetani

B. Clostridium botulinum C. Clostridium perfringens D. Clostridium difficile

C. tetani causes lockjaw. C. botilinum causes botulism. C. difficile causes antibiotic associated pseudomembranous colitis. C. perfringens cause gasgangrene and Food poisoning.

(17)

106. This gram positive rod is usually associated with bacterial vaginosis producing malodorous vaginal discharge and "clue cells"

A. Erysipelothrix rhusopathiae B. Lactobacillus acidophilus C. Gardenella vaginalis D. Propionibacterium acnes

E. rhusopathiae causes erysipeloid skin infection that resembles erysipelas occurring among meat and fish handlers. L. acidphilus is normal flora of genital tract and is the main source of lactic acid. P. acnes produces lipase which contributes to the genesis of acne.

Reference: Zinsser p. 604-605

107. Which of the following organisms is MOST likely to involve invasion of the intestinal mucosa.

A. Vibrio cholera B. Shigella sonnei C. Enterotoxigenic E. coli D. Clostridium botulinum

Shigella sonnei is the only invasive, presence of blood and mucus in the stool. Clostridium botilinum , V. cholera and Enterotoxigenic E. coli causes diarrhea by producing enterotoxin

108. Food poisoning that produces gastrointestinal symptoms approximately 1-2 hours after eating is most likely to be due to:

A. Salmonella enteritidis B. Campylobacter jejuni C. Clostridium perfringens D. Staph. aureus

Staph aureus – the incubation period is 1-2 hrs. after ingestion of

contaminated food. Sal. enteritidis – 6 hrs. – 2 days. Campylobcacter – 8 hrs. – l day. C. perfringens – 8 hrs. – 12 hrs. Bacillus aureus – 8 hrs. – 12 hrs. V. cholera – 2 – 3 days. V. parahaemolyticus – 8 hrs. – 2 days

109. A 30 year old pregnant woman had a normal delivery but the fetus was stillborn. CSF examination showed positive rods. The pathogen is most likely:

A. Listeria monocytogenes B. Gardenerella vaginalis C. Group B Streptococcus D. Staphylococcus aureus

Listeria monocytogenes is a gram positive rod and can infect pregnant women and poses the threat of stillbirth or serious damage to the fetus and also cause neurological disease. Gardenella vaginalis gives rise to frothy, fishy odor vaginal discharge, it can also cause premature births and low-birth-weight infants.

(18)

110. Which of these organisms is a major pathogen for nosocomial infections because of its ubiquitous present in the hospital environment?

A. Staph. Aureus B. Staph. Epidermidis C. Serratia marcescens

D. Pseudomonas aeroginosa

Pseudomonas aeruginosa, S. aureus - yellow gold pigment when cultured at room temperature. S, epidermidis - white pigment when cultured at room temperature. Serratia marcescens - red pigment

111. An individual experiences severe diarrhea after eating sushi (raw fish) in a West Coast restaurant. The most probable etiologic agent is:

A. Yersenia enterocolitica B. Salmonella enteritidis C. Shigella sonnei

D. Vibrio parahaemolyticus

Vibrio parahaemolyticus - is a salt loving organism and found in fishes. Salmonella enteritidis - found in chicken, pig. Yersenia enterocolitica- reserviors rodents

112. When symptoms to typhoid fever first become apparent, Salmonella typhi is most frequently isolated from:

A. Feces B. Urine C. Blood

D. Bone marrow

Blood - on the first week of infection, Feces - second week. Urine - third week.

113. The area in the body where Salmonella typhi resides if one is a chronic carrier A. small intestine

B. kidney

C. blood stream D. gall bladder

Gall bladder - where organisms are found and are excreted in the stool and urine of the chronic carrier of Salmonella.

114. A 3 year old boy was diagnose to have meningitis CSF culture on Chocolate agar showed growth of small gram negative rods. The most probable etiologic agent is:

A. N. meningitides B. S. aureus

C. Group B Streptococcus D. H. influenzae type b

H. influenzae type b - is the most commonly isolated etiologic gram negative rods causing meningitis. N. meningtidis gram negative plo. Group B Strep -gram positive cocci.

(19)

115. Among the gram negative rods producing gastroenteritis, the most infectious is: A. V. cholera

B. E. coli (0157) C. Sal. Typhimurium

D. Shig. Dysenteriae type 1

Shigella - only 200 cells is enough to cause diarrhea while A-C you need to 10 3_{- 10}5_{cells to produce infection.}

Reference: Tortora et al

116. Pneumococci primarily cause disease by: A. toxin production

B. enzyme production

C. eluding phagocytosis and favoring invasiveness D. producing delayed immunologic reaction

Pneumococci does not produce toxins and enzymes. Capsules are virulence factors which interfere with phagocytosis and favoring invasiveness.

117. The formation of pseudomembrane in diphtheria is due to:

A. inhibitions by toxin of protein synthesis by ADP ribosyslation of EF-2 B. spores which spread subcutaneously

C. invasion of mononuclear phagocytic cells

D. neutralization of exotoxin by antibody of blocking the interaction of fragment B with receptors

Diphtheria toxin inhibits protein synthesis of eukaryotic cells thereby causing cell death. Pseudomembrane formation is due to accumulation of necrotic tissue.

118. Lyme disease is an endemic inflammatory disorder with this distinctive skin disorder. A. Chronic dermatitis

B. erythema marginatum

C. erythema chronicum migrans D. ecthyma gangrenosum

Erythema chronicum migrans is a tick-borne associated syndrome. Reference: Lippincott Illustrated Review in Microbiology p. 225

119. Serology in the diagnosis of Syphilis using a non-treponemal tests is the following EXCEPT:

A. Microhemagglutination assay

B. Venereal Disease Research Laboratory C. Fluorescent Antibody Tests

D. Reiter Protein Complement Fixation

Two different types of test are used. Non-treponemal tests detects

Wasserman or reagenic antibodies; a few examples of the nontreponemal tests include VDRL, automated regin, Kahn, plasmacrit, Hinton and Kline tests. Treponemal tests detect antibodies specific for treponemal antigens; they include FTA=ABS, T. pallidium immunobolization and hemagglutination tests.

(20)

120. Mycoplasmas are very pleomorphic and cannot be classified as to shape because they lack the following:

A. Peptidoglycan B. lipid bilayer C. nucleus

D. lipopolysaccharide

Lacking cell walls, mycoplasmas are enclosed instead by a membrane composed of a lipid bilayer. They are therefore plastic and very pleomorphic. Reference: Zinsser p. 733

121. A definitive identification of M. tuberculosis can be obtained by doing the following procedure?

A. Ziehl-Neelsen stain B. AFB Culture

C. Biopsy of Tuberculin test D. Nucleic acid amplification

Cultures can detect small numbers of organism in the original sample. The presence of Acid-fast organism on Ziehl Neelsen cannot distinguish on morphologic groups M. tuberculosis from the other mycobacteria that are saprophytic. Nucleic acid amplification utilizes enzymes that rapidly IGS ribosomal RNA which can be used for patients with positive smears and while culture results are pending.

Reference: Lippincott Illustrated Review for Microbiology p. 251 122. Rifamficin a broad antimicrobial agent is effective treatment for tuberculosis by:

A. selective inhibition of the biosynthesis of the arabinogalactan and lipo-arabinomannan

B. mediating drug permeability and efflux

C. Inhibiting peptidoglycan synthesis by blocking action of D-alanise synthesis D. binding to RNA polymerase thereby interfering with mRNA synthesis

Rifamficin is a broad spectrum antimicrobial agent that acts the interferring with the synthesis of mRNA by binding to RNA polymerase. Selective inhibitions by ethamentol of the biosynthesis of arabinogalactan and

lipoarabinomannan, key structural components of the mycobacterial cell wall. Cyclosine inhibits synthesis of peptidoglycan by blocking the action of the D-alanine synthetase.

Reference: Tortora p. 561

123. In primary disease, M. tuberculosis survives and grows within these host cells A. macrophages

B. basophils C. neutrophils D. eosinophils

M. tuberculosis may continue to survive and remain dormant in activated macrophages where it is protected from phagocytosis

Reference: Lippincott Illustrated Review of Microbiology p. 247 124. Members of the genus Rickettsia are morphologically & biochemically similar to

A. gram-positive bacteria B. gram negative bacteria C. clostridia

(21)

Rickettsias are short-rod shaped or cocci bacillary organisms measuring 0.8 to 2.0 um long

Reference: Lippincott Illustrated Review of Microbiology p. 259 125. The hallmark of viral infection of the cell is the production of

A. inclusion bodies

B. multinucleated giant cells C. cytopathic effect

D. granule formation

The hallmark of viral infection of the cell is the cytopathic effect. This change begin with a rounding and darkening of the cell and culminates in either lysis or giant cell formation. Infected cells frequently contain inclusion bodies which are discrete areas containing viral particles.

126. The complete infectious forms of Hepatitis B is: A. HBeAg

B. Dane particles C. HBsAg

D. HBcAg

The Dane particle is the complete form of Hepatitis B whereas the antigens are subunit forms of the surface and core of the virus.

127. Which of the following virus/es contain/s Hemagglutinin on its surface? A. Hepatitis B

B. Hepatitis C C. Influenza virus D. all of the above

The antigen hemagglutinin is characteristic of Influenza virus. Reference: Zinsser p. 995

128. In their multiplication, they produce DNA which is integrated into the cell genome. A. Hepadnavirus

B. Reovirus C. Picornavirus D. Herpesvirus

Hepadnavirus transforms non-permissive cells by integration of DNA transcripts into host cell genome. They carry an RNA-dependent DNA polymerase (reverse transcriptase).

129. The most common intrauterine viral infection is caused by: A. Cytomegalovirus

B. Rubella C. Adenovirus D. Herpes simplex

Cytomegalovirus accounts for the biggest # of intrauterine infection followed by rubella.

(22)

130. Smallpox was eradicated by the global use of vaccine which contains: A. killed virus

B. attenuated live virus C. preformed antibodies

D. preformed antibodies and live attenuated virus

Smallpox disease was eradicated by use of a live attenuated vaccine. Live vaccine are used because duration of immunity is longer with greater

effectiveness of protection, both IgA and IgG are elicited when administered by the natural route of infection which is intradermally where the virus

replicates. Cell mediated immunity is produced. Reference: Zinsser p. 949

131. The most important laboratory test for the detection of early Hepatitis B virus infection is: A. immunoassay for HBsAg

B. immunoassay for HBeAg C. immunoassay for Anti HBc D. immunoassay for Anti HBs

HBsAg appears during the incubation period and is detectable in most patients during the prodrome and acute phase; falls to undetectable levels during convalescence. HBeAg arises during the incubation period and is present during the prodome and early acute disease. Its presence is an important indicator of transmissibility. Anti HBc is detectable during prodrome and acute disease. Anti HBs is detectable during late convalescence.

132. A common upper respiratory tract disease produced by adenovirus is: A. Rhinitis

B. atypical pneumonia C. pharyngoconjunctivitis D. parotitis

Adenoviruses cause a variety of upper and lower respiratory tract disease. Pharyngoconjunctivitis is common.

133. The virus that is increasingly being recognized as cause of nonbacterial infant diarrhea A. Retrovirus

B. Rotavirus C. Orbivirus D. Calicivirus

Rotavirus gastroenteritis is one of the most common childhood illness and a leading cause of infant deaths in developing countries.

134. In the laboratory this protein from Influenza virus agglutinates red blood cells whereas in vivo, it binds to the surface receptor of the host cell to initiate infection.

A. Hemagglutinin B. Neuramidase C. Hemolysin D. capsid antigen

The Influenza virus has an envelope covered with 2 different spikes

Hemagglutinatinin and neuramidase. Hemagglutination initiates infection in the host and in the lab causes agglutination of RBC's. Neuramidase cleaves

(23)

neuramic acid (sialic acid) to release progeny virus from the infected cell. Hemolysin is from bacterial cells and causes hemolysis of RBC.

135. In the prevention of poliomyeletis, the use of oral vaccine is preferred because: A. induces intestinal IgA

B. induces humoral IgG

C. can produce lifelong immunity

D. can produce immunity to unimmunized adults

The oral vaccine or Sabin vaccine which is a live attenuated vaccine is preferred over the Salk vaccine or killed vaccine because (1) it interrupts fecal-oral transmission by inducing secretory IgA in the GIT; killed vaccine does not. Both kinds of vaccine induce humoral IgG. Infection provides lifelong type specific immunity.

136. Hand-foot-and-mouth disease characterized by versicular rash on the hands and feet and ulcerations in the mouth, mainly in children is caused by:

A. Echovirus

B. Parainfluenza virus

C. Coxsackie virus Group A D. Coxsackie virus Group B

Echovirus causes aseptic meningitis. Parainfluenza causes croup. Coxsackie B causes pleurodynia. Coxsackie A causes herpangina and hand-foot-and-mouth disease.

137. The most common fungal opportunistic infection is caused by: A. Aspergillus fumigatus

B. Cryptococcus neoformans C. Candida albicans

D. Mucor

Candida albicans - it is endogenous, a lot of risk factors like pregnancy, diabetic person, prolonged used of antibiotic, used of birth control pills Reference: Zinsser p. 1139

138. The most common mode of infection of systemic fungi is thru: A. ingestion

B. traumatic implantation C. inhalation

D. all of the above

Inhalation of infectious particles (spores) which are suspended in the air. Reference: Zinsser p. 1091

139. A 45 year old post kidney transplant patient develop fever and pneumonia with marked neutropenia. Bronchial washing show dichotomously branching filamentous fungi. The fungi involved is:

A. sprorothrix B. cryptococcus C. candida D. aspergillus

(24)

In immunocompromised patient, inhalation of spores of Aspergillus can lead to pneumonia and are seen as dichotomous branching hyphae

(filamentous).

140. In a 7 year old malnourished boy with multiple nematode infections, the most severe complication will come from:

A. Ascaris lumbricoides B. Trichuris trichiura C. Necator americanus D. Enterobius vermicularis

Ascaris has a tendency to migrate to other openings causing more severe disease.

Reference: Brown 6th_{ed. p. 141-142, Roberts and Janovy p. 422}

141. Loeffler’s syndrome can be seen in the following parasitic infections EXCEPT: A. Ascariasis

B. Strongyloidiasis C. Necatoriasis D. Trichuriasis

Loeffler’s syndrome is eosinophilic lung. As the parasitic larvae (rhaditiform for Ascaris, filariform for Strongyloides and Necator) travels to the pulmonary-circulatory system, the body reacts with an anaphylactic type of

hypersensitivity that produces the eosinophilic lung condition. Trichuris does not have a pulmonary circulatory pathway.

Reference: Brown 6th_{ed. p. 141, 126, 130; Roberts & Janovy p. 386, 422}

142. All cestodes require an intermediate host EXCEPT: A. Diphyllobothrium latum

B. Taenia saginata C. Hymenolepis nana D. Echinococcus granulosus

Man gets H. nana infection by ingesting the eggs directly. All other cestodes require an intermediate host

Reference: Brown 6th_{ed. p. 192}

143. Cysticercosis due to Taenia solium is acquired through ingestion of: A. cysticercus larva

B. cysticercoid larva C. procercoid larva D. egg

A more dangerous sequence can occurs when a person ingests the egg of Taenia solium in contaminated food or water rather than eating raw or

undercooked pork containing the larva cystercus. Cysticercoid larva pertains to D. caninum and H. nana. Procercoid larva is for D. latum. The ingested egg hatch in the small intestines and the oncopheres burrow through the wall into a blood vessel, where they can disseminate to many organs. This

condition is called cysticercosis. Reference: Brown 6th_{ed. p. 207}

(25)

144. The infective stage to man of Necator americanus is: A. rhabditiform larva

B. filariform larvae C. embryonated egg D. Microfilaria

Filariform larvae of hookworms penetrate the skin Reference: Roberts & Janovy p. 410

145. This cestode possess a quadrate scolex with 4 circular suckers and no rostellum or hooklets:

A. Diphyllobothrium latum B. Hymenolepis nana C. Taenia saginata

D. Echinococcus granulosus

D. latum has an elongated scolex. H. nana has a globular scolex with 4 suckers, a short retractile rostellum armed with a single row of hooklets. E. granulosus has 4 suckers with a rostellum and a double row of hooklets. Reference: Brown 6th_{p. 194, Roberts & Janovy p. 333}

146. Amoebic abscess of the liver is mostly found in the A. left anteromedial lobe

B. right posterosuperior lobe C. inferior lobe

D. middle lobe

Spread of amoeba from the large intestines is by the portal vein and deposit on the right posterosuperior lobe

Reference: Chatterjee p. 25

147. Little Joey was frequently sick of various infectious diseases. He was found to have low CD4+ lymphocytes titers. Which of the following immune response processes would still be functional in Joey’s body?

A. T cell help for B lymphocytes

B. Recognition of peptide-MHC complex

C. Phagocytic function for foreign molecules D. T-dependent antigen recognition

This is an innate natural cellular immune ability of the host to respond to foreign molecules which is independent of the Th series.

Reference: Stanley p. 92; 124

148. The host immune response in viral infections is mostly by: A. Th cells

B. B cells C. Tc cells D. NK cells

Viral infections produce endogenous peptides which are presented on the surface of cells in conjunction with MHC Class 2. These are recognize primarily by Tc cells. B cells are mostly for exogenous peptides that are antibody mediated mainly stimulated by Th cells while the NK cells’ major activity is to directly destroy aberrant cells such as in cancer.

(26)

149. A killed virus is the major component of the vaccine against this pathogenic organism. A. measles

B. rubella C. mumps D. rabies

Measles, rubella, mumps vaccines contain living but attenuated virus (also for chickenpox, Sabin polio) Rabies vaccine (also for Hep A, Salk polio,

influenza) contain killed or inactivated viruses. Hep B vaccine contains antigenic fragments of the virus usually using recombinant technology (yeast-derived). Subunit vaccines are also used as in pertussis. Tetanus and

diphtheria utilize toxoids which are inactivated toxins or antitoxins, antibodies against these. H. influenzae type b vaccine is conjugated to a protein which can be a diphtheria toxoid.

Reference: Tortora p. 502

150. Alkaline pH in urine seen in Proteus is due to its ability to split urea into: A. NH3 & C02

B. Cl & Ca C. Ca & Mg D. Na & Cl

Answer: A (pp.208)

151. It is responsible for Escherichia coli causing meningitis in infants A. H antigen

B. LPS C. K antigen D. O antigen

Answer: C (pp.208) 152. Vi antigen for Salmonella typhi

A. penetrates epithelial lining of the intestinal tract B. antigenic structure associated with invasiveness C. interfere with antibody binding to bacteria

D. confers a certain degree of immunity Answer: B (p 209)

153. Initial recognition event for the activation of the alternative pathway A. C3b

B. C1 C. C4 D. Factor D

Answer: A (p 108)

154. The characteristic morphologic feature of influenza responsible for antigenic changes of the virus A. Envelope B. segmented genome C. capsid D. nucleic acid Answer: B (p 320)

(27)

155. Replicate in the cytoplasm of the host cell A. Adenovirus B. Orthomyxovirus C. Poxviruses D. HIV Answer: C (p332)

156. The exudative lung parenchymal lesion with lympadenopathy in primary tuberculosis infection is called A. tuberculosis B. granuloma C. ghon complex D. fibrotic lesion Answer: C (p278)

157. Which of the following statement/s is correct regarding neonatal herpes A. infections are almost always asymptomatic

B. most common route of infection is thru contact with herpetic lesion during vaginal delivery

C. causes latent infection D. usually cause by HSV 1

Answer: B (p376)

158. An 18 year old college student developed fever followed by jaundice. Acute viral

hepatitis was entertained. Results of the hepatitis profile are as follows: anti-HAV IgM (-), anti-HbsAg (-), anti-HBc IgM (+), anti-HBc IgG negative. He most probably has:

A. Hepatitis A B. Hepatitis B C. Hepatitis C D. Hepatitis E

Answer: B ( p 410)

159. A 21 y/o male with history of sexual contact 4 days ago resents with painful urination and purulent penile discharge. Which of the following is most likely?

A. primary syphilis B. genital herpes C. gonorrhea

D. lymphogranuloma venerum Answer: C (p259)

160. A 1 and half y/o boy developed fever, coryza and cough followed 4 days later by maculopapular rashes starting from the hairline and becoming generalized. Fever persisted. The most likely etiology is a/an

A. RNA virus B. DNA virus

C. gram positive coccus D. gram negative bacillus

(28)

161. A neonate is born with the following features: microcephaly, jaundice, poor suck and chorioretinitis. A congenital infection is entertained. The most common congenital infection is due to:

A. Chlamydia B. HIV

C. CMV D. HSV

Answer: C ( p 382)

162. A 2 month old girl was brought to you because of milk curd-like lesions in the mouth noted for a week. The whitish lesions were adherent to the oral mucosa with pinpoint bleeding when the mother tried to remove them. This is caused by

A. herpes simplex 1 B. Coxsackie A C. albicans D. neoformans

Answer: C ( p 550)

163. A 23 y/o office worker found out that his sexual partner had HIV infection. The screening procedure of choice for HIV infection is

A. PCR B. HIV Elisa C. western blot D. northern blot

Answer: B (p 525)

164. A 6 month old baby has acute watery diarrhea. Which of the following is the most common cause of diarrhea in this age group?

A. ETEC B. Rotavirus C. EPEC D. V. cholerae

Answer: B ( p434)

165. A health worker who did not receive prior mumps vaccine developed parotid swelling and fever. The following belongs to the same virus family as mumps virus

A. A. german measles B. RSV

C. Influenza

D. Japanese B virus Answer: B ( p 471)

166. A 25 yr old saleslady developed high fever, chills and cough. On PE she had crackling rales on the right lung base. The diagnosis is pneumonia. The most common bacterial cause of this condition in this age group is:

A. S. aureus B. N. meningitidis C. S. pneumoniae

D. Hemophilus influenzae Answer: C ( p 213)

(29)

167. Infection with this organism is the most common risk factor for cervical CA A. HIV B. N. gonorrhea C. HPV D. HSV 2 Answer: C ( p512)

168. Most common cause of UTI in women is characterized by A. Urease production

B. fruity odor on culture C. greenish metallic sheen D. swarming phenomenon

Answer: C ( p 219)

169. Which of the following laboratory tests can be used to monitor response to treatment in syphilis? A. FTA-ABS B. VDRL C. Darkfield microscopy D. ELISA Answer: B ( p 287)

170. An encapsulated fungi that causes meningitis is A. H. capsulatum

B. neoformans C. C albicans D. immitis

Answer: B ( p 552)

171. The following statements are true regarding N. meningitidis A. it is the only specie that is oxidase positive

B. oxidizes maltose and glucose C. oxidizes glucose only

D. it is the only gram negative specie Answer: B (p256)

172. The following statements are true about S. aureus A. it is catalase negative

B. can secrete preformed toxins C. prefers anaerobic condition D. cannot grow in 7.5% NACL

Answer: B (p.199)

173. Toxic shock syndrome secondary to Staphylococcus tend to commonly cause infection among

A. tampon users B. asthamtics C. IV drug users D. infants

(30)

174. A 14 year old male has high fever for a week, tonsillitis, hepatosplenomegaly and cervical lymphadenopathy. Peripheral smear shows 10% atypical lymphocytes. The most likely diagnosis is:

A. Streptococcal sore throat B. leukemia

C. infectious mononucleosis D. diphtheria

Answer: C (p 386)

175. Streptococcal sore throat is definitively diagnosed by A. ASO titer

B. throat swab culture

C. rapid antigen testing from throat swab D. Gram stain

Answer: B (p 210)

176. Which of the following, when positive, indicates an acute Epstein-Barr virus infection? A. anti-EBNA

B. anti-VCA IgG C. anti-VCA IgM D. anti-EBV DNA

Answer: C (p 388)

177. The hallmark of Dengue Hemorrhagic Fever is A. thrombocytopenia

B. shock C. plasma loss

D. positive tourniquet test Answer: C (p 452)

178. Dengue virus has how many serotypes? A. one

B. two C. three D. four

Answer: D ( p 452)

179. The most common vector of Dengue virus is ( p 452) A. Anopheles minimus

B. Mansonia sp. C. Aedes aegypti D. Aedes albopictus

180. A 1 year old girl has high fever for four days, coryza, hacking cough and poor

appetite. On PE, she has congested pharynx and Koplik’s spots. The causative agent of this condition

A. is a DNA virus B. has three serotypes

C. belongs to the paramyxovirus family D. has double-stranded RNA

(31)

181. Which of the following diseases is currently vaccine-preventable? A. cytomegalic inclusion disease

B. German measles C. Dengue fever D. Hepatitis C

Answer: B ( p 485)

182. A 20 year old male developed fever, vomiting and poor appetite for four days followed by jaundice. A diagnosis of viral hepatitis is entertained. The results of the hepatitis profile are as follows: positive HAV IgM, negative anti-HBsAg, positive anti-HBsAg, negative anti-HBc IgM. Which is correct?

A. The patient has acute Hepatitis A and is most likely a Hepatitis B carrier B. He has acute Hepatitis B

C. He has acute Hepatitis C

D. He does not have acute viral hepatitis Answer: A ( p 411)

183. The protective antibody following immunization against Hepatitis B is A. anti-HBc IgM

B. anti-HBc IgG C. anti-HBsAg D. anti-HCV

Answer: C ( p 415)

184. Which of the following agents of viral hepatitis is fecal-oral in transmission and causes more severe disease in pregnant women?

A. Hepatitis A B. Hepatitis B C. Hepatitis C D. Hepatitis E

Answer: D ( p 408)

185. Bovine spongiform encephalopathy (mad cow disease) is caused by an agent which has the following characteristic

A. double-stranded DNA B. single-stranded RNA C. double-stranded RNA D. does not contain nucleic acid

Answer: D ( p 500)

186. Human influenza virus which undergoes antigenic shift and can cause pandemics A. influenza A

B. influenza B C. influenza C

D. highly-pathogenic avian flu Answer: A (p 463)

(32)

187. Fetal hydrops is a prominent complication of maternal infection with A. rubella B. parvovirus B19 C. measles D. cytomegalovirus Answer: B ( p 357)

188. An 8 month old girl developed high fever for three days but was otherwise playful. On the fourth day, fever was gone but she had maculopapular rashes on the face

which rapidly spread all over the body. This common disease is caused by A. measles virus

B. human herpesvirus 6 C. parvovirus B19

D. rubella virus Answer: B ( p389)

189. A 22 year old sex care worker wanted to be tested for human immunodeficiency virus (HIV). What test would you initially recommend?

A. Western blot B. HIV Elisa C. CD4:CD8 ratio D. VDRL

Answer: B ( p 526)

190. HIV infection causes the ratio of CD4 to CD8 T cell ratio to fall. CD4 T cells are also called A. T cytotoxic cells B. cytolytic T cells C. T helper cells D. suppressor T cells Answer: C (p 521)

191. The major function of CD8 T lymphocytes is

A. to kill cells infected by intracellular pathogens like viruses B. antibody-dependent cellular cytotoxicity

C. opsonization D. phagocytosis

Answer: A (p 116)

192. A one and a half year old boy has recurrent bacterial pneumonia and middle ear infection. An antibody deficiency is entertained. Antibodies are produced in large quantities by A. B lymphocytes B. T lymphocytes C. plasma cells D. mast cells Answer: C (p 125)

(33)

193. Immunoglobulins aid phagocytosis because they can bind to phagocytes via A. Fab receptors B. Fc receptors C. CD4 receptors D. C3b receptors Answer: B ( p 125)

194. The following virus/viruses exhibit/s latency in nerve ganglia A. smallpox virus

B. chickenpox virus C. cytomegalovirus D. adenovirus

Answer: B (p 378)

195. A virus which infects B lymphocytes by attaching to the latter’s complement Receptors

A. cytomegalovirus B. Epstein-Barr virus C. Japanese B encephalitis virus D. HIV

Answer: B ( p 386)

196. A 1 year old infant had exposure to a caregiver with cavitary tuberculosis. Chest x-ray was negative. Mantoux test done showed induration of 12 mm after 2 days. The Mantoux tuberculin test result is an example of

A. Type I hypersensitivity B. Type II hypersensitivity

C. delayed-type hypersensitivity D. Arthus reaction

Answer: C ( p 130)

197. The following are characteristics of M. tuberculosis A. have minimal lipid content in their cell wall B. cannot be grown on artificial media

C. retain carbolfuchsin dye after exposure to acid-alcohol D. appear as round chains on Gram stain

Answer: C ( p25)

198. Subacute sclerosing panencephalitis is a late complication of infection with this virus A. Varicella

B. Rubeola C. West Nile virus D. poliovirus

Answer: B ( p483)

(34)

199. A newborn presents with lethargy, purpura, chorioretinitis and pulmonary infiltrates. Which of the following could be a cause of this syndrome?

A. Amebiasis B. Candidiasis

C. Cytomegalovirus D. Human papillomavirus

ANS: C

Medical Microbiology by Jawetz.,23rd edition, page 445

200. Which one of the following is a subcellular structure that is found only in Gram negative bacteria? A. endospores B. lipopolysaccharide C. mitochondria D. phosphatidylethanolamine ANS: B

Medical Microbiology by Jawetz., 23rd ed., page 28

201. Which one of the following statements best describes a function of the peptidoglycan layer in bacteria?

A. The ability of bacteria to survive changes in the osmolarity of their environment is due to the physical properties of the peptidoglycan layer.

B. The peptidoglycan layer contains all the enzymes responsible for the synthesis of membrane phospholipids.

C. The peptidoglycan layer protects bacteria from the effects of ultraviolet light.

D. The peptidolgycan layer renders Gram negative bacteria resistant to detergents.

ANS: A

202. 4. Which one of the following structures is responsible for the passage of low molecular weight solutes through the outer membrane of Gram negative bacteria?

A. capsules B. endospores C. flagella D. porins ANS: D

203. Your patient, suffering from a bacterial infection, receives a penicillin injection and almost immediately experiences respiratory distress and loses consciousness. This reaction is MOST LIKELY mediated by

A. complement.

B. CD8+ cytolytic T cells. C. macrophages.

D. mast cells. ANS: D

(35)

204. Which one of these statements explains the origin of Rh antibodies in the blood of an Rh-negative mother?

A. They are naturally occurring in the blood of all Rh-negative persons. B. They are received through mis-matched blood transfusions.

C. They are synthesized by the mother in response to Rh-positive cells from her first child.

D. They are transferred from the Rh-positive father during intercourse. ANS: C

205. Which one of the following bacterial pathogens requires selective culture conditions for reliable isolation from the stool, including media with antibiotics and incubation at 42 C in increased CO2?

A. Campylobacter jejuni

B. Enterohemorrhagic Escherichia coli C. Salmonella sp.

D. Shigella sp. ANS: A

206. 11. Which one of the following is considered facultatively intracellular for human macrophages?

A. Enteroinvasive Escherichia coli B. Enterotoxigenic Escherichia coli C. Salmonella typhi

D. Shigella sp. ANS: C

207. A 20-year-old female presents with severe pelvic pain, fever, nausea and vomiting. She was on the second day of her menstrual cycle. A purulent cervical discharge was

detected upon physical examination. Oxidase positive, Gram-negative diplococci were isolated on Thayer Martin agar from the endocervical swab. What is the MOST LIKELY identity of this organism?

A. Bordetella pertussis B. Chlamydia trachomatis C. Haemophilus ducreyi D. Neisseria gonorrhoeae

ANS: D

208. A large outbreak of food poisoning occurred at a company picnic. Eighty people reported explosive vomiting and diarrhea within 3 hours after eating. All of the victims recovered within 24 hours without medical intervention. No known bacterial or viral pathogens were isolated from the stool of affected individuals. A survey of the food eaten at the picnic suggested that potato salad was the common source of the

poisoning. The individual who prepared the salad had a sty on her left eye. Which one of the following is the MOST LIKELY cause of this outbreak?

A. Clostridium perfringens B. Salmonella typhimurium C. Staphylococcus aureus

(36)

ANS: C

209. Gram-positive cocci and polymorphonuclear leukocytes are observed on Gram stain of sputum from a 60-year old alcoholic with pneumonia. Culture of the sputum reveals alpha-hemolytic, catalase-negative bacteria. Which one of the following laboratory tests is the MOST APPROPRIATE next step in the definitive identification of this organism?

A. bacitracin sensitivity test

B. beta-lactamase production test C. ELEK test

D. bile solubility test ANS: D

210. A 19-year old female is admitted to an outpatient clinic with suprapubic pain, dysuria and an urgency to urinate frequently. She is otherwise healthy. A clean catch midstream urine specimen was collected and sent to the laboratory. Numerous neutrophils are detected in the urine sample. The bacteriology laboratory reports that less than 102 Gram-positive cocci and greater than 105 Gram-negative bacilli were recovered per milliliter of urine. Which one of the following is the most likely cause of her infection?

A. Escherichia coli B. Klebsiella pneumoniae C. Pseudomonas aeruginosa D. Staphylococcus aureus

ANS: A

211. A 40-year old male hog farmer complains of intermittent fever, night sweats and headaches to his physician. The patient is hospitalized and blood and bone marrow specimens are collected. The physician requests that the laboratory incubate the

cultures for at least 6 weeks. Nine days after admission, Gram negative coccobacilli that require increased CO2 for growth are isolated from the blood and bone marrow

cultures. The patient is most likely to be suffering from which one of the following diseases?

A. Brucellosis B. Bubonic plague C. Legionnaire’s disease

D. Rocky Mountain spotted fever ANS: A

212. Which one of the following diseases is most likely to respond favorably to treatment with a -lactam antibiotic? A. Legionellosis B. Mycoplasmosis C. Syphilis D. Trachoma ANS: C

(37)

213. A 20-year old woman comes to your clinic complaining of an irritating vaginal discharge. Upon examination, you find that the cervix and vaginal walls appear normal. The discharge is thin and milky, pH 5.5, and has a fishy odor when treated with potassium hydroxide. You are unable to detect pseudohyphae, buds, or flagellates upon

microscopic examination. A Gram stain reveals numerous curved Gram-negative rods, epithelial cells, and clue cells, but relatively few Gram-positive rods or WBCs. Cervical and vaginal cultures are negative for STDs. What is your diagnosis?

A. Bacterial vaginosis B. Cervicitis

C. Trichomoniasis D. Vaginal candidiasis

ANS: A

214. A 75-year old man in a nursing home is treated with a broad spectrum antibiotic for bed sores. Two days later he develops bloody diarrhea. A stool specimen from the patient is positive in an ELISA test for a necrotizing cytotoxin, and his treatment is switched to vancomycin. The agent MOST LIKELY to be responsible for this clinical syndrome is

A. Bacteroides fragilis. B. Campylobacter jejuni. C. Clostridium difficile. D. Escherichia coli O157:H7.

ANS: C

215. Which one of the following toxins is responsible for scalded skin syndrome? A. Alpha hemolysin

B. Exfoliatin C. Hyaluronidase

D. Staphylococcal enterotoxin ANS: B

216. A 50-year old cancer patient with severe neutropenia became septic two weeks after being admitted to the hospital. An oxidase-positive, Gram-negative rod that did not ferment glucose was isolated from the patient’s blood. Which one of the following organisms is the most likely cause of the patient’s sepsis?

A. Enterobacter cloacae B. Escherichia coli

C. Klebsiella pneumoniae D. Pseudomonas aeruginosa

ANS: D

217. Blood culture from a 12-year old with acute osteomyelitis yields Gram-positive cocci that are b hemolytic and catalase positive. Which one of the following laboratory tests is the MOST APPROPRIATE next step in the definitive identification of this organism?

A. Coagulase test

B. Optochin sensitivity test

C. Slide agglutination test for capsular antigen type D. Test for capacity to grow in bile esculin

(38)

218. Activated macrophages are the effector cells in the expression of a protective, cell-mediated immune response against

A. Corynebacterium diphtheriae. B. Haemophilus influenzae type b. C. Listeria monocytogenes. D. Streptococcus pneumoniae.

ANS: C

219. A patient recovering from a crushing leg injury suffered during an a motorcycle accident develops a temperature of 100o F, a rapid pulse, and extreme pain at the site of his the wound two days after the accident. The skin overlying the patient’s sutured wound is brownish- white, shiny, and studded with vesicles. Gram stain of the watery exudate from the wound reveals Gram-positive rods, Gram-negative rods, and Gram-positive cocci. The Gram-positive rods are MOST LIKELY

A. Bacillus cereus. B. Bacteroides fragilis.

C. Clostridium perfringens. D. Corynebacterium ulcerans.

ANS: C

220. A 13-year old and her 10-year old brother are seen at an emergency room with

complaints of double vision, difficulty swallowing, and progressive muscular weakness. A detailed history reveals that both children attended a church picnic three days earlier but neither child has gastroenteritis. The MOST LIKELY presumptive diagnosis is

A. botulism.

B. Chinese rice syndrome. C. Guillan-Barré syndrome. D. salmonellosis.

ANS: A

221. Epidemics of bacterial meningitis in young, previously healthy adults are MOST LIKELY caused by

A. Escherichia coli K-1.

B. Haemophilus influenzae type b. C. Listeria monocytogenes.

D. Neisseria meningitidis group A. ANS: D

222. A 55-year old woman develops endocarditis following oral surgery. Gram-positive, alpha-hemolytic, catalase-negative cocci are isolated from a blood culture. The MOST LIKELY agent is

A. Enterococcus faecalis (group D streptococci). B. Staphylococcus aureus.

C. Streptococcus pyogenes (group A streptococci). D. Viridans streptococci.

ANS: D

(39)

223. A 2-month old infant is admitted to the hospital with fever, lymphocytosis, and bouts of violent coughing that often end in vomiting. The infant’s mother reveals that the child has not as yet received any immunizations. The attending physician swabs the infant’s nasopharynx and requests that the swab be plated on routine media as well as a

special medium (Bordet-Gengou) that contains blood and glycerol. No organisms are found on blood or chocolate agar, but small Gram-negative rods are isolated on Bordet-Gengou agar. The MOST LIKELY cause of the infant’s illness is

A. Bordetella pertussis. B. Chlamydia pneumoniae. C. Moraxella catarrhalis. D. Mycoplasma pneumoniae.

ANS: A

224. Which one of the following viruses establishes a chronic persistent infection in humans? A. Hepatitis A virus

B. Hepatitis C virus C. Herpesvirus

D. Poliovirus ANSWER: B

Medical Microbiology by Jawetz., 23rd ed., page 475-476

225. Which one of the following viruses is transmitted via the gastrointestinal route? A. Delta-associated agent

B. Hepatitis A C. Hepatitis B D. Hepatitis C

ANSWER: B

226. A 33-year-old pregnant woman delivered a baby boy via a normal vaginal delivery. Neither she nor the father has a history of genital or oral herpes. Although she had chickenpox as a child, she was exposed to a child with chickenpox about 10 days before delivery. There was no evidence of vesicular skin lesions on either the mother or the child at the time of delivery. Three days after birth, the baby now develops

vesicular skin lesions on his back, accompanied by a fever. Which one of the following viruses is MOST LIKELY to be the cause of the baby's infection?

A. Cytomegalovirus

B. Herpes simplex virus type 1 C. Herpes simplex virus type 2 D. Human herpesvirus 6

ANSWER: C

227. Examination by dark-field microscopy of scrapings from a genital ulcer of 19-year old female reveals mobile, spiral-shaped organisms against a black background. The MOST LIKELY diagnosis is

A. chancroid.

B. Chlamydia trachomatis infection. C. gonorrhea.

(40)

228. Gram-positive cocci are observed on a Gram stain of purulent discharge from a skin lesion of a 7-year-old. Culture of the exudate reveals beta-hemolytic, catalase-positive organisms. Which one of the following laboratory tests is the MOST APPROPRIATE next step in the definitive identification of this organism?

A. Bacitracin sensitivity test B. Bile solubility test

C. Coagulase test

D. Optochin sensitivity test ANS: C

229. Which one of the following species or serovars of Chlamydia can be transmitted as a zoonotic infection?

A. Chlamydia pneumoniae B. Chlamydia psittaci

C. Chlamydia trachomatis serovar C D. Chlamydia trachomatis serovar D

ANS: B

230. Gram stain of synovial fluid from the knee of a 20-year-old woman with arthritis reveals Gram-negative cocci. To isolate the MOST LIKELY responsible agent, the specimen should be plated on

A. Bordet-Gengou agar. B. Chocolate agar.

C. Eosin Methylene Blue (EMB) agar. D. MacConkey agar.

ANS: B

231. The formation of colonic ulcers and absesses during Shigella dysentery is due to A. ability of bacteria to survive stomach acidity because of the production

of urease.

B. bacterial survival within macrophages.

C. invasion of enterocytes and cell-to-cell spread of the bacteria. D. production of a superantigen by the bacillus.

ANS: C

Medical Microbiology by Jawetz., 23rd ed., page 255-256

232. Which one of the following organisms is the MOST COMMON cause of bacterial traveler’s diarrhea?

A. Campylobacter jejuni

B. enterotoxigenic Escherichia coli C. Salmonella cholerasuis

D. Shigella sonnei ANS: B