LE 3 - Micro Flashcards by

Which of the following structures do not contribute to the virulence of N. gonorrhea?
a. Lipooligosaccharide
b. IgA protease
c. Pili
d. Axial filaments

d. Axial filaments

Axial filaments are associated with spirochete bacteria like Treponema pallidum, which causes syphilis, not with Neisseria gonorrhoeae. The other structures listed (Lipooligosaccharide, IgA protease, and Pili) all contribute to the virulence of N. gonorrhoeae.

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One of the following conditions is not caused by S. aureus. Which one?
a. Cellulitis
b. Impetigo
c. Scarlet fever
d. Toxic shock syndrome

c. Scarlet fever (S.pyogenes)

Scarlet fever is caused by Streptococcus pyogenes (Group A Streptococcus). The other conditions (Cellulitis, Impetigo, and Toxic shock syndrome) can be caused by Staphylococcus aureus.

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The most common etiologic agent of pneumonitis with microabscesses is
a. Streptococcus pneumoniae
b. Mycoplasma pneumonia
c. Staphylococcus aureus
d. Klebsiella pneumonia

c. Staphylococcus aureus

Staphylococcus aureus is commonly associated with pneumonitis characterized by microabscesses.

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The following are superantigens of S. aureus, except
a. Coagulase
b. Enterotoxin
c. TSST-1
d. Exfoliative toxin

a. Coagulase

Examples of superantigens include:

1.	Toxic Shock Syndrome Toxin-1 (TSST-1) produced by Staphylococcus aureus.
2.	Staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus.
3.	Streptococcal pyrogenic exotoxins (SPEs) produced by Streptococcus pyogenes.

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Which of the following is the most common cause of UTI in females?
a. Staphylococcus aureus
b. Escherichia coli
c. Staphylococcus saprophyticus
d. Klebsiella pneumonia

c. Staphylococcus saprophyticus

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A quick laboratory test that differentiates Staphylococcus from Streptococcus is
a. Optochin test
b. Coagulase test
c. Catalase test
d. Hemolysis

c. Catalase test

Rationale:
- Optochin test: Used primarily to differentiate Streptococcus pneumoniae (sensitive) from other viridans streptococci (resistant).
- Coagulase test: Identifies Staphylococcus aureus by its ability to clot plasma. Not used to differentiate between the genera Staphylococcus and Streptococcus.
- Catalase test: The key test to differentiate Staphylococcus (catalase-positive) from Streptococcus (catalase-negative).
- Hemolysis: Refers to the lysis of red blood cells on blood agar. Both Staphylococcus and Streptococcus species can show different patterns of hemolysis, so it’s not definitive for differentiating between the two genera.

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Most common cause of septic arthritis:
a. S. aureus
b. N. gonorrhea
c. S. pyogenes
d. S. epidermidis

a. S. aureus

Keywords:

•	S. aureus: Most common, all age groups
•	N. gonorrhea: Sexually active, young adults
•	S. pyogenes: Less common cause
•	S. epidermidis: Prosthetic joint infections

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The principal habitat of N. meningitidis in carriers is:
a. Meninges
b. Nasopharynx
c. Lungs
d. Nasal mucosa

b. Nasopharynx

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The most common cause of bacterial meningitis in the newborn:
a. N. meningitidis
b. E. coli
c. S. pneumonia
d. S. aureus

b. E. coli

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A 25-yo sexually active female students presents with dysuria and purulent vaginal discharge a week after having unprotected sex with a former highschool classmate during a reunion. What is the most sensitive diagnostic method for determining the most likely etiologic agent?
a. Gram stain
b. Bacterial culture on selective media
c. Nucleic acid amplification test
d. serology

c. Nucleic acid amplification test

Nucleic acid amplification tests (NAATs) are highly sensitive and specific for detecting sexually transmitted infections, including those causing symptoms like dysuria and purulent vaginal discharge. This method can help identify the most likely etiologic agent, such as Chlamydia trachomatis or Neisseria gonorrhoeae, in a case like this.

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A notorious actor presented with septic arthritis which he experienced repeatedly during the last few years. Knee fluid aspirate culture on chocolate agar was positive for N. gonorrhea. The patient should be evaluated for?
a. A polymorphonuclear cell chemotactic factor
b. Myeloperoxidase deficiency
c. Selective IgA deficiency
d. Deficiency of a late acting complement C5, C6, C7, C8

d. Deficiency of a late acting complement C5, C6, C7, C8

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A 40 y/o carpenter was diagnosed to have osteomyelitis. He underwent surgery where bone debridement and drainage of pus was done. Culture yielded S. aureus. Based on this information, you know the organism is:
a. beta lactamase
b. susceptible to nafcillin
c. encapsulated
d. catalase positive

d. Catalase positive

Staphylococcus aureus is catalase positive, which means it produces the enzyme catalase, allowing it to convert hydrogen peroxide into water and oxygen. This characteristic is used in the laboratory to help differentiate it from other bacteria.

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A 25 year old housewife was diagnosed to have a tubo-ovarian abscess after consulting at the OPD of a hospital. She presented with moderately high grade fever accompanied by left lower quadrant pain and tenderness upon palpation of her uterus. History is positive for unprotected sex. Secretions from her endocervix yielded gonorrhoeae. What might be the common sequelae of the condition.
a. infertility
b. cervical ca
c. urethral stricture
d. uterine fibroid tumor

a. Infertility

Tubo-ovarian abscesses can lead to damage and scarring of the fallopian tubes and ovaries, which can result in infertility due to impaired function of these reproductive organs. It’s essential for the patient to receive prompt treatment to minimize the risk of long-term complications like infertility.

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Antimicrobial resistance has become a significant problem. Which one of the following is of major concern worldwide regarding resistance?
a. Penicillin in N. gonorrhea
b. Penicillin in S. pneumonia
c. Nafcillin in S. aureus
d. Vancomycin in S. aureus

d. Vancomycin in S. aureus

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Coagulase is not thought to be an important virulence factor of Staphylococcus aureus.
a. TRUE
b. FALSE

b. FALSE

Coagulase is considered an important virulence factor of Staphylococcus aureus. It allows the bacteria to clot plasma, which can help protect the bacteria from phagocytosis and the immune system. Coagulase-positive strains of Staphylococcus aureus are typically more virulent than coagulase-negative strains.

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Staphylococcus have positive catalase tests.
a. TRUE
b. FALSE

a. TRUE

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S. epidermidis does not have coagulase.
a. TRUE
b. FALSE

a. TRUE

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Staphylococcus aureus causes Toxic shock syndrome because of its enterotoxins which are heat stable and resistant to gut enzymes.
a. TRUE
b. FALSE

b. FALSE

While Staphylococcus aureus does produce enterotoxins, it is the Toxic Shock Syndrome Toxin-1 (TSST-1) that is primarily responsible for causing Toxic Shock Syndrome (TSS). TSST-1 is a superantigen, not an enterotoxin. The enterotoxins produced by Staphylococcus aureus are associated with food poisoning due to their heat stability and resistance to gut enzymes, but they are not the primary cause of TSS.

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Neisseria species are best identified with coagulase tests.
a. TRUE
b. FALSE

b. FALSE

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A 40 y/o carpenter was diagnosed to have osteomyelitis. He underwent surgery where bone debridement and drainage of pus was done. Culture yielded S. aureus. Based on this information, you know the organism is:
a. catalase positive
b. Beta-lactamase negative
c. Coagulase negative
d. Oxidase positive

a. catalase positive

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Which of the following characteristics differentiates S. aureus from the non-pathogenic species of staphylococcus?
a. Pigment production
b. Catalase positive
c. Coagulase positive
d. All of the choices are correct

c. Coagulase positive

Staphylococcus aureus is coagulase positive, which means it produces the enzyme coagulase that can cause the blood to clot. This is a key distinguishing feature of S. aureus compared to other Staphylococcus species, and it is often used in the laboratory to differentiate pathogenic S. aureus from non-pathogenic Staphylococcus species. Pigment production (choice a) and catalase positivity (choice b) are not unique to S. aureus and can also be found in other Staphylococcus species.

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Characteristics of Streptococcus pneumoniae
a. Not inhibited by optochin on solid media
b. Gram positive diplococci
c. Arranged in clusters
d. Autolysis is decreased by surface acting agents

b. Gram positive diplococci

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There are many diseases attributable to invasion of S.pyogenes. What is the most serious sequelae of S.pyogenes infection?
a. Sub Acute nasopharyngitis
b. Acute Glomerulonephritis
c. Rheumatic Fever
d. Streptococcal pyoderma

c. Rheumatic Fever

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Considered to be the drug of choice for Streptococcus pneumoniae
a. Penicillin G
b. Vancomycin
c. Erythromycin
d. Tetracycline

a. Penicillin G

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Rheumatic fever is most commonly caused by a. Streptococcus viridans b. Streptococcus pyogenes c. Staph aureus d. Strep pneumoniae

b. Streptococcus pyogenes

Penicillin is drug of choice of a. Scarlet fever b. Whooping cough c. brucellosis d. syphillis

d. Syphilis Penicillin has long been the primary treatment for syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum. It is highly effective in treating and curing syphilis at various stages of the disease. The other conditions listed have different preferred treatments.

Virulence factor for streptococcus pneumoniae a. Capsular polysaccharide b. Vi antigen c. Specific soluble substance d. F antigen

a. Capsular polysaccharide

44. Conjunctivitis in a newborn is caused by a. streptococcus b. meningococci c. pneumococcus d. E coli

a. streptococcus

1. Thayer Martin agar contains antibiotics which make it a selective medium for A. Staphylococcus aureus B. Streptococcus pyogenes C. Neisseriae gonorrhea D. Esheichia coli

C. Neisseriae gonorrhea

2. Drug of choice for Streptococcus pneumoniae A. Erythromycin B. Penicillin G C. Vancomycin D. Cefotaxime

B. Penicillin G

3. This disease usually follows an acute infection and is commonly preceded by skin infection. A.Streptococcal shock syndrome B. Rheumatic fever C. Scarlet fever D.Glomerulonephritis

D. Glomerulonephritis Specifically, post-streptococcal glomerulonephritis can develop after an infection with certain strains of streptococcus bacteria, often following a throat or skin infection (like impetigo).

4. A 28 year old nurse was brought to the ER because of hypotension, headache, muscle ache, abdominal cramps, and diarrhea. PE revealed the presence of an erythematous rash and an intact tampon as she was menstruating at that time. Her kidney function test were normal indicative of mild renal failure. Her illness is likely to be caused by which of the following? A. a toxin that degrades sphingomyelin B. a toxin that blocks elongation factor (EF2) C. a toxin that results in greatly increased levels of intracellular CAMP D. a toxin that stimulates up to 10% T cells to be non-specifically activated

D. a toxin that stimulates up to 10% T cells to be non-specifically activated

5. A quick laboratory test that differentiates Staphylococcus from Streptococcus is A. Catalase test B. Coagulase test C. Hemolysis D. Optochin test

A. Catalase test

7. This organism produces dextrans and levans from sucrose contributing to dental caries formation A. Streptococcus N B. Streptococcus C and G C. Streptococcus angionosus D. Streptococcus mutans

D. Streptococcus mutans

8. One of the following conditions is not caused by S. aureus. Which one? A. Cellulitis B. Toxic shock syndrome C. Scarlet fever D. Impetigo

C. Scarlet fever

9. Produces dome shaped colonies later forming a central plateau with an elevated rim A. Streptococcus N B. Streptococcus bovis C. Viridans streptococcus D. Streptococcus pneumoniae

D. Streptococcus pneumoniae

10 . A notorious actor presented with septic arthritis which he rexperienced repeatedly during the last few years. Knee fluid aspirate culture on chocolate agar was positive for N. gonorrhea. The patient should be evaluated for? A. A polymorphonuclear cell chemotactic factor B. Myeloperoxidase deficiency C. Selective IgA deficiency D. Deficiency of a late acting complement C5, C6, C7, C8

D. Deficiency of a late acting complement C5, C6, C7, C8

11. This is the component of diptheria toxin responsible for the arrest of protein synthesis producing the necrotizing and neurotoxic effects a. fragment b b fragment c c fragmend d d fragment a

d fragment a

12. Non- enterococcal group D streptococci and part of the enteric flora a. streptococcus bovis b non of the choices are correct c. streptococcus group c and d d strepotococcus agalactiae

a. streptococcus bovis Streptococcus bovis is a non-enterococcal group D streptococcus and is part of the enteric (intestinal) flora.

13. Most prevalent members of normal flora of the upper respiratory tract and is important for the mucus memebrane A. Streptococcus C and G B. Viridans Streptococcus C. Streptococcus milleri D. Streptococcus N

B. Viridans Streptococcus

14.Diagnostic laboratory test used to identify C. diphtheriae a. none of the above b. blood agar c. dacron swabs d. Thayer martin agar

b. blood agar

15. what antigenic structure of S. aureus important to bacterial attachment to host cells has become an important reagent in immunology (coaglutinnation) a. peptidoglycan b. polysaccharide capsule c. Protein A d. teichoic acid

c. Protein A

17 A lipophilic corynebacteria commonly isolated from acuteely ill and immunocompromised patients A. Corynebacterium urealyticum B. Corynebacterium hemolyticum C. Rhodococci equi D. Corynebacterium jeikeium

D. Corynebacterium jeikeium

18 Drug of choice to C. diphtheriae a. Cephalosporins b. Fluoroquinolones c. Penicillin G d. Erythromycin

c. Penicillin G

19 This bacteria is Gram positive,endospore forming anaerobe found in the stool of many healthy adults, infection is usually precipitated by the extended use of antibiotics especially fluroquinolones A. Clostridium difficle B. Bacillus cereus C. Vibrio cholerae D. Campylobacter

A. Clostridium difficle

20. This following is true of the antigenic structure of enterobacteriaceae a. antibodies to O antigens are predominantly IgG b. H antigens may interfere with agglutination by O antisera and they may be associated with virulence c. H antigens are located on flagella and are denatured or removed by heat or alcohol d. O antigens are susceptible to heat and alcohol and usually are detected by bacterial agglutination

c. H antigens are located on flagella and are denatured or removed by heat or alcohol

21. A 3 year-old toddler came to the ER looking acutely ill with fever. He started to develop a petechial rash which was noted to be increasing rapidly. Your impression is menigococcemia. What would be your first step to confirm the diagnosis so you can institute immediate therapy? A. blood culture B. Culture on Thayer-Martin VCN media of skin scrapings C. CBC D. gram stain of petechia

D. gram stain of petechia

22. Which of the following shigella specie will present a positive ornithine carboxylase A.S. Flexneri B. S. Dysenteriae C. S. Sonnei D. S. Boydii

C. S. Sonnei

25. Lethal dose of diptheria toxin A. 0.1 ug/kg B. 0.2 ug/kg C. 0.2 ug/kg D. 0.1 ng/kg

A. 0.1 ug/kg

26The exfoliative toxins of s aureus , TSST-1 and the enterotoxin are all superantigens. The genes for these toxins are a. widely distributed on the staphylococcal chromosome b on plasmids c present in all strains of s aureus d. on the staphylococcal chromosome in a pathogenicity island

d. on the staphylococcal chromosome in a pathogenicity island

28. Coagulase is not thought to be an important virulence factor fo Staphylococcus aureus A. True B. False

B. False

29. Characteristics of streptococcus pneumoniae A. Not inhibited by optochin on solid media B. Gram positive diplococci C. Arranged in clusters D. Autolysis is decreased by surface acting agents

B. Gram positive diplococci

30. Virulence of the C. diphtheriae is mainly due to: A. Effective absorption of the toxin is produced B. Slow growth C. Capacity to enter the blood stream D. Capacity to invade deep tissues

A. Effective absorption of the toxin is produced. The virulence of Corynebacterium diphtheriae, the bacterium responsible for diphtheria, is primarily due to the diphtheria toxin it produces. This exotoxin inhibits protein synthesis in host cells by targeting elongation factor 2 (EF2). When released by the bacterium and taken up by host cells, the toxin can cause cell death, leading to the characteristic symptoms of diphtheria.

31. The basis of Lancefield Classification A. Capsular polysAccharide B. Carbohydrate group-specific substance C. Enzyme presence D. Resistance or Susceptibility to test chemical agents

B. Carbohydrate group-specific substance

33. A 40 y/o carpenter was diagnosed to have osteomyelitis. He underwent surgery where bone debridement and drainage of pus was done. Culture yielded S. aureus. Based on this information, you know the organism is: A. beta lactamase B. susceptible to nafcillin C. encapsulated D. catalase positive

D. catalase positive

34. Loeffler slant diagnostic procedure yields result in A. 6-12 B. 48 hours C. 12-18 hours D. 24 hours

C. 12-18 hours

35. Which of the following characteristics differentiates S. aureus from the non- pathogenic species of staphylococcus? A. Pigment production B. Catalse positive C. All of the choices are correct D. Coagulase positive

D. Coagulase positive

37. Empirical treatment for N gonorrhea infection is generally penicillin a. true b false

b. false Historically, penicillin was used to treat Neisseria gonorrhoeae infections. However, over time, N. gonorrhoeae has developed resistance to penicillin. As of my last update in 2022, ceftriaxone and azithromycin are recommended as empirical treatments for gonorrhea due to increasing resistance to other antibiotics. Always consult the latest guidelines and a healthcare professional when considering treatment options.

38. Doses of Penicillin and Erythromycin resulting in effective tissue levels occurs in A. 14 Days B. 10 days C. 21 days D. 8 days

B. 10 days

39.a 55 year-old man develops an abscess on his left inguinal area. Culture yields S. Aureus. The isolate is tested and found to be positive for meCA Gne. Which means that the isolates is: A. susceptible to nafcillin B. resistant to vancomycin C. resistant to nafcillin D. susceptible to vancomycin

B. resistant to vancomycin

40A 10yo boy succumbed to death because of meningococcemia. Which of the following measures should be considered to protoect the bereaved householdmember a. no prophylaxis at all b. give n meningitidis pilin vaccine c. rifampin prophylaxis d. sulfonamide propphylaxis

c. rifampin prophylaxis

3. Which of the following individual’s should routinely receive vaccination with the conjugate meningococcal vaccine? a. Asplenic individuals b. Healthy adolescent entering high school c. A healthy child entering kindergarten d. A 65-year-old man with diabetes type 1

a. Asplenic individuals Asplenic individuals are at an increased risk for invasive meningococcal disease and should routinely receive vaccination with the conjugate meningococcal vaccine.

44. this is responsible for the differentiation of certain types of streptococci by agglutination with anti- serum a none of the choices are correct b nucleoprotein c t substance d m protein

d. m protein M protein is responsible for the differentiation of certain types of streptococci by agglutination with antiserum. It is a major virulence factor of some streptococci, especially Streptococcus pyogenes.

45. Most serious sequelae of S. pyogenes damaging hear muscles and valves A. streptococcal shock Syndrome B. Glomerulonephritis C. Scarlet fever D. Rheumatic fever

D. Rheumatic fever

46. This is a poststreptococcal disease which is commonly preceded by a respiratory tract infection. A. Rheumatic fever B. Streptococcal shock syndrome C. Glomerulonephritis D. Scarlet fever

C. Glomerulonephritis

47 Which of these gonococcal molecules can frequently switch from one antigenic form to another, such that they can elude the host immune system? A. pilin B. All of the choices are correct C.Opa D. LPS

B. All of the choices are correct

49. True about the resistance to penicillin, ampicillin and similar durgs observed in S. aureus A. All of the choices are true B. beta-lactamase production is common C. beta-lactamase is plasmid mediated D. plasmids are transmitted by transduction

A. All of the choices are true

53. A 25 yo sexually active female student presents with dysuria and purulent vaginal discharge a weel after having unprotected sex with a highschool classmate during a reunion. What is the most sensitive diagnostic method for determining the likely etologic agent? A. Serology B. Bacterial Culture on selective media C. Gram Stain D. Nucleic acid amplification test

D. Nucleic acid amplification test

54. The following are effects of diphtheria toxin A. Fatty infiltration B. Parenchymatous degeneration C. All are effects D. Nerve Damage

C. All are effects

55. Drug of choice for treating Streptococcus pyogenes A. Fluoroquinolones B. Cephalosporins C. Penicillin G D. Vancomycin

C. Penicillin G

56. The following is/are non lipophilic bacteria A. C. Ulcerans B. R. equi C. C. Urealyticum D. C. jeikeium

A. C. Ulcerans

58. the most common etiologic agent of pneumonitis with microabsesses is a. staphylococcus aureus b mycoplasma pneumonia c. klebsialle pneumonia d. streptococcus pneumoniae

a. staphylococcus aureus

62. Which of the following is the most common cause of UTI in females? a. Proteus mirabilis b. Staphylococcus aureus c. Staphylococcus saprophyticus d. Escherichia coli

c. Staphylococcus saprophyticus

63. characteristics of matte colony form of Streptococcus pyogenes a. both more virulent and has less M proteins b. none of the choices are correct c. less M proteins d. more virulent

d. more virulent

66 Tellurite medium used in the diagnostic procedure for C. diphtheriae and yield results in a. 6-12 hours b. 60 hours c. 24-48 hours d. 12-18 hours

c. 24-48 hours

67 an enzyme cobined with streptokinase used in enzymatic debridement and liquefaction of exudates A. Streptodornase B. Fibrinolysin C. Pyrogenic exotoxins D. Hyaluronidase

A. Streptodornase When used in enzymatic debridement, streptokinase is often combined with streptodornase to help liquefy exudates and degrade necrotic tissue.

68. ultimate source of Streptococcus pyogenes a. spread of infection through droplets from the respiratory tract b. subclinically infected persons c. none of the choice are correct d. part of the normal human flora

b. subclinically infected persons

69. N. gonorrhea can cause A. infective endocarditis B. septic arthritis C. Both D. Neither

C. Both

70. Major virulence factor and appear as hairlike projection of the cell wall A. Capsular Polysaccharides B. M Proteins C. T Substance D. Hemolysin

B. M Proteins

71. A 25 year old housewife was diagnosed to have a tubo-ovarian abscess after consulting at the OPD of a hospital. She presented with moderately high grade fever accompanied by left lower quadrant pain and tenderness upon palpation of her uterus. History is positive for unoprotected sex. Secretions from her endocervic yielded n gonorrhea. What might be the common sequelae of the condition. a infertility b cervical ca c urethral stricture d uterine fibroid tumor

a infertility

75. In a sexually active healthy female, gonorrhea must often present as a. cervicitis b. urethritis c. PID d. asymptomatic disease

d. asymptomatic disease. Many women with gonorrhea are asymptomatic. However, when symptoms do occur, cervicitis is a common presentation. If left untreated, it can progress to more serious complications like pelvic inflammatory disease (PID). Urethritis can also occur but is more commonly associated with males.

77. This is the process where there is capsular swelling with polyvalent anti- serum A. Enzymatic degradation B. None of the choices C. EIA D. Quellung reaction

D. Quellung reaction

78. Antimicrobial resistance has become a significant problem. Which one of the following is of major concern worldwide regarding resistance? A. Penicillin in N. gonorrhea B. Penicillin in S. pneumonia C. Nafcillin in S. aureus D. Vancomycin in S. aureus

D. Vancomycin in S. aureus

1. Corynebacterium jeikium is: a. Catalase negative b. Gram negative c. Often multidrug resistant d. Motile e. Common but clinically unimportant

c. Often multidrug resistant

The following is/ are non-lipophilic bacteria a. C. urealyticum b. R. equi c. C. jeikeium d. C. ulcerans

d. C. ulcerans

A lipophilic corynebacterial commonly isolated from acutely ill and immunocompromised patients a. R. equi b. C. urealyticum c. C. hemolyticum d. C. jeikeium

d. C. jeikeium

Diagnostic laboratory tests used to identify Corynebacterium diptheriae a. Dacron swabs b. Thayer- Martin agar c. None of the above d. Loeffler's medium

d. Loeffler's medium

Tellurite medium is used in the diagnostic procedure for C. diptheriae and yield results in: a. 6-12 hours b. 60 hours c. 24-28 hours d. 12- 18 hours

c. 24-28 hours

1. Doses of penicillin and erythromycin resulting in effective tissue levels occurs in a. 10 days b. 14 days c. 21 days d. 7 days

a. 10 days

2. Ultimate source of Streptococcus pyogenes a. Sub clinically infected persons b. Spread of infection through droplets from the respiratory tract c. Part of the normal human flora d. None of the above

a. Sub clinically infected persons

3. This is responsible for the differentiation of certain types of streptococci by agglutination with anti-serum a. M protein b. T substance c. Nucleoproteins d. None of the above

a. M protein

4. Drug of choice for treating Streptococcus pyogenes a. Penicillin G b. Cephalosporin c. Vancomycin d. Fluoroquinolones

a. Penicillin G

5. Which of the following genera is typically resistant to vancomycin? a. Aerococcus b. Gemella c. Pediococcus d. Streptococcus e. Abiotrophia

c. Pediococcus Pediococcus species are typically resistant to vancomycin.

6. The most serious sequelae of Streptococcus pyogenes damaging heart muscle and valves: a. Rheumatic fever b. Glomerulonephritis c. Steprococcal shock syndrome d. Scarlet fever

a. Rheumatic fever

7. Voges-Proskauer positive a. S. agalactiae b. S. Mutans c. S. anginosus d. S. aureus

d. S. aureus

1. The peptidoglycan in the cell wall of S. aureus is destroyed by a. Lysozyme b. None of the choices is correct c. Both strong acid and lysozyme d. Strong acid

a. Lysozyme

2. A quick laboratory test that differentiates Staphylococcus from Streptococcus a. Optochin test b. Catalase test c. Coagulase test d. Hemolysis

b. Catalase test

3. Bacteremia a. Enteric fever b. Neither enteric fever no bacteremia with focal lesions c. Both enteric fever and bacteremia with focal lesions d. Bacteremia with focal lesions

d. Bacteremia with focal lesions

4. The following are superantigens of S. aureus EXCEPT a. Coagulase b. Exfoliative toxin c. Enterotoxin d. TSST-1

a. Coagulase

A 36-year-old male patient has an abscess with a strain of S. aureus that is ß-lactamase positive. This indicates that the organism is resistant to which of the following antibiotics? a. Penicillin G, ampicillin, and piperacillin b. Trimethoprim-sulfamethoxazole c. Erythromycin, clarithromycin, and azithromycin d. Vancomycin (E) Cefazolin and ceftriaxone

a. Penicillin G, ampicillin, and piperacillin

Which of the following statements regarding the role of protein A in the pathogenesis of infections caused by S. aureus is correct? a. It is responsible for the rash in toxic shock syndrome b. It converts hydrogen peroxide into water and oxygen c. It is a potent enterotoxin d. It is directly responsible for lysis of neutrophils. e. It is a bacterial surface protein that binds to the Fo portion of IgG1

e. It is a bacterial surface protein that binds to the Fo portion of IgG1

Which of the following statements best describes the function of the agr in S. aureus? a. It regulates production of ß-hemolysins b. It is influenced by environmental oxygen c. It controls the preferential expression of surface adhesins. d. It is important in the control of autolysis

c. It controls the preferential expression of surface adhesins. The agr system in Staphylococcus aureus is a quorum-sensing system that regulates the expression of various virulence factors in response to changes in cell population density. One of its primary functions is to coordinate the switch between surface adhesin production (important in the early stages of infection for bacterial attachment and colonization) and the secretion of toxins and proteases (important for invasion and dissemination in later stages of infection).

In sepsis, which of the following diseases caused by gram-negative bacteria demonstrates 50 to 100-fold greater endotoxin levels? a. Disseminated gonorrhea b. Typhoid fever c. Meningococcemia

c. Meningococcemia

Ophthalmia neonatorum a. Both N. meningitidis and N. gonorrhoeae b. N. meningitidis c. N. gonorrhoeae d. Neither N. gonorrhoeae nor N. meningitidis

c. N. gonorrhoeae

10. Lacks polysaccharide capsule a. Both N. meningitidis and N. gonorrhoeae b. N. meningitidis c. N. gonorrhoeae d. Neither N. gonorrhoeae nor N. meningitidis

c. N. gonorrhoeae

Which of these gonococcal molecules can frequently switch from one antigenic form to another, such that they can elude the host immune system? a. Pilin b. LPS c. All of the choices are correct d. Opa

b. LPS

Kidney-shaped diplococci a. Both N. meningitidis and N. gonorrhoeae b. N. meningitidis c. N. gonorrhoeae d. Neither N. gonorrhoeae nor N. meningitidis

a. Both N. meningitidis and N. gonorrhoeae