Chapter 18 Microbiology

1. A common food intoxication is caused by enterotoxin-producing strains of A. Staphylococcus aureus. B. Staphylococcus epidermidis. C. Staphylococcus saprophyticus. D. Streptococcus pyogenes. E. Streptococcus agalactiae.

A

16. Rebecca Lancefield differentiated streptococci on the basis of differences in their A. cell wall carbohydrates in a serological test. B. patterns of hemolysis on blood agar. C. ability to produce catalase. D. Gram stain appearance. E. All of these choices are correct.

A

2. All species of Staphylococcus A. produce catalase. B. are motile. C. have endospores. D. produce coagulase. E. All of these choices are correct.

A

22. The Group A streptococcal infection that has symptoms of fever, edema of skin near portal of entry, and an elevated red, hot vesicular lesion is A. erysipelas. B. impetigo. C. necrotizing fasciitis. D. scarlet fever.

A

32. All of the following pertain to gonorrhea, except A. a chancre-type lesion develops at the portal of entry. B. it is a reportable infectious disease. C. pelvic inflammatory disease (PID) and infertility are complications. D. female infections are frequently asymptomatic. E. symptoms include painful urination and discharge.

A

36. Most cases of otitis media in children are due to infection with A. Streptococcus pneumoniae. B. Streptococcus pyogenes. C. Branhamella (Moraxella) catarrhalis. D. Streptococcus agalactiae. E. Staphylococcus saprophyticus.

A

70. An 8-month old infant has been brought to the ER with a high fever. Her parents indicate that she has not been eating or drinking well and has been very irritable until the last few hours during which she has been only minimally responsive. Suspecting meningitis, a spinal tap is done and the CSF sample is sent to the lab for analysis. The white blood cell count on the sample is profoundly elevated, the protein content is elevated, and the glucose level is depressed. The Gram stained smear shows gram-positive cocci in pairs. Cultures are done and after overnight incubation, alpha hemolytic colonies are observed on the blood plate. These colonies contain gram-positive cocci, which are catalase negative. An optochin susceptibility test is done and there is a large zone of inhibition around the disk. What is the identification of this isolate? A. Streptococcus pneumoniae B. viridans Streptococci C. Enterococcus faecalis D. Neisseria meningitidis E. Streptococcus agalactiae

A

9. Which pathogen has drug-resistant strains called MRSA? A. Staphylococcus aureus B. Staphylococcus epidermidis C. Staphylococcus saprophyticus D. Streptococcus pyogenes E. Streptococcus agalactiae

A

14. Symptoms of Toxic Shock Syndrome include all the following, except A. fever and muscle pain. B. appearance of flesh being "eaten" down to the muscle. C. nausea, vomiting and diarrhea. D. sunburn-like rash. E. kidney and liver failure.

B

26. All of the following are associated with subacute endocarditis, except A. it occurs in patients that have prior heart damage. B. it is caused by immune system autoantibodies that attack heart and valve tissue. C. oral bacteria get introduced by dental procedures to the blood. D. bacteria colonize previously damaged heart tissue resulting in vegetation. E. signs and symptoms include fever, heart murmur, and possible emboli.

B

3. The enzyme that coagulates plasma is A. catalase. B. coagulase. C. hyaluronidase. D. staphylokinase. E. Dnase.

B

30. Meningococcemia is A. common during gonorrhea. B. associated with vascular hemorrhage and petechiae. C. frequently seen in elderly. D. caused by a gram-positive diplococcus. E. All of these choices are correct.

B

40. A pregnant woman is told she has a positive CAMP test and should be treated with a course of antibiotics. This test is indicative of A. Group A streptococci. B. Group B streptococci. C. S. saprophyticus. D. S. epidermidis. E. S. aureus.

B

42. All of the following are correct about Staphylococcus aureus, except A. it is the coagulase-positive species. B. the body's most powerful defense against it lies in the T-cell response. C. carriers may be treated with antibiotics to clear them of the bacteria. D. most strains are resistant to penicillin and ampicillin. E. it causes furuncles, carbuncles, and abscesses.

B

43. Sue brought her daughter Amy to the pediatrician complaining of a sore throat. The physician examines Amy and observes that her throat is bright red and there are white pus-filled nodules on her tonsils. Which of the following conclusions should be made? A. She has a strep throat and should begin antibiotics. B. She should have a rapid strep test performed before a diagnosis is made. C. She should go home and rest because most sore throats are viral in origin. D. She should go home and come back in two days for a strep test since it may take that long to show up. E. She has a staphylococcal sore throat and should begin antibiotics immediately.

B

45. Which of the following antibiotics specifically disrupt protein synthesis of streptococci? A. β-lactams B. macrolides C. cephalosporins D. ansamycin plural E. aminoglycosides

B

68. Which of the following organisms would look most similar to Neisseria meningitidis on a Gram stained smear? A. Staphylococcus aureus B. Branhamella catarrhalis C. Streptococcus agalactiae D. Streptococcus pneumoniae

B

10. The most common site where carriers of Staphylococcus aureus carry this pathogen is A. all over the skin. B. under the fingernails. C. anterior nares (nostrils). D. mouth. E. intestines.

C

11. Infections caused by Staphylococcus aureus include all of the following, except A. folliculitis. B. furuncles and carbuncles. C. sore throat. D. osteomyelitis. E. pneumonia.

C

15. Staphylococci can be differentiated from streptococci by the A. Gram stain. B. coagulase test. C. catalase test. D. fermentation of mannitol.

C

17. The M protein of Streptococcus pyogenes A. is the basis for the organism belonging to Lancefield Group A. B. gives rise to a zone of beta hemolysis on blood agar. C. protects against phagocytosis and enhances adherence. D. is also called streptokinase. E. protects against lysozyme damage.

C

21. Necrotizing fasciitis is A. also called impetigo. B. possibly caused by antibodies to Group A streptococci that cross-react with body tissues. C. associated with strains of Streptococcus pyogenes producing destructive enzymes and toxins. D. typically a sequelae of streptococcal pharyngitis. E. not treatable with antimicrobic drugs.

C

27. Streptococcus pneumoniae is A. called the meningococcus. B. in the viridans group. C. a gram-positive diplococcus with a capsule. D. a pathogen with endotoxin. E. All of these choices are correct.

C

38. Which chemical, produced by S. aureus, digests blood clots? A. coagulase B. penicillinase C. staphylokinase D. hyaluronidase E. toxic shock syndrome toxin

C

41. All of the following are correct about Streptococcus pyogenes, except A. humans are the only significant reservoir. B. some of the streptococcal toxins act as superantigens. C. most strains do not have a capsule. D. it can cause impetigo and erysipelas. E. infection is generally through direct contact.

C

44. If left untreated, an infection with ___ can lead to pelvic inflammatory disease and infertility. A. Streptococcus pneumoniae B. Neisseria meningitidis C. Neisseria gonorrhoeae D. Streptococcus pyogenes E. Staphylococcus aureus

C

67. Having received no prenatal care, a young woman arrives at a hospital after many hours of labor and delivers a baby girl. Three days later the baby girl is listless, nursing poorly, and is running a fever. Blood cultures are done, and after 24 hours, they are Gram stained and show the presence of gram-positive cocci in pairs and short chains. Upon subculture, these form colonies that are beta hemolytic on blood agar. Further tests demonstrate that the isolate is catalase negative, resistant to bacitracin, and is CAMP test positive. What is the identification of this organism? A. Streptococcus pyogenes B. Streptococcus pneumoniae C. Streptococcus agalactiae D. Staphylococcus aureus E. Neisseria meningitidis

C

8. Which organism is associated with commonly causing urinary tract infections in sexually active young adult and adolescent females? A. Staphylococcus aureus B. Staphylococcus epidermidis C. Staphylococcus saprophyticus D. Streptococcus pyogenes E. Streptococcus agalactiae

C

A 48-year old man has had nasal surgery and absorbent material has been inserted into his nasal cavity to control bleeding. Several hours ago he began to complain of a headache and has since developed a red rash over much of his body and is experiencing muscle cramps and diarrhea. His blood pressure has dropped to 75/50 mg Hg. This patient's illness is most likely caused by A. Staphylococcus aureus — exfoliative toxin B. Streptococcus pyogenes — streptolysin O C. Staphylococcus aureus — toxic shock syndrome toxin D. Streptococcus pyogenes — erythrogenic toxin

C

12. Which is incorrect about Staphylococcus aureus food intoxication? A. Food becomes contaminated by a human carrier. B. Common associated foods include custards, ham, cream pastries, processed meats. C. After contamination, food must be left unrefrigerated for a few hours. D. Ingestion of the pathogen allows it to multiply and damage the GI tract lining. E. Symptoms come on quickly, and include nausea, vomiting, diarrhea.

D

19. Streptococcal pharyngitis involves all the following, except A. a purulent exudate over the tonsils. B. can lead to scarlet fever if it is an erythrogenic toxin-producing strain. C. can lead to serious sequelae. D. is usually caused by the viridans streptococci. E. causes redness, difficulty in swallowing, and fever.

D

23. Long-term sequelae of Group A streptococcal infections include all the following, except A. risk decreased with prompt treatment of skin infections and pharyngitis. B. development of rheumatic fever. C. appearance of sequelae within a few weeks after an initial infection. D. transmission of sequelae via respiratory secretions from a patient with streptococcal sore throat. E. development of acute glomerulonephritis.

D

29. People at greatest risk for pneumococcal infections include all the following, except A. elderly. B. those with underlying lung disease and viral infections. C. patients without a spleen. D. adolescents and young adults. E. young infants.

D

34. The instillation of antibiotics in newborn's eyes will prevent ophthalmia neonatorum in newborns. This disease is caused by A. Neisseria meningitidis. B. Staphylococcus aureus. C. Streptococcus pyogenes. D. Neisseria gonorrhoeae. E. Branhamella (Moraxella) catarrhalis.

D

37. Which chemical produced by S. aureus is also known as "spreading factor"? A. coagulase B. penicillinase C. hemolysin D. hyaluronidase E. toxic shock syndrome toxin

D

4. The toxin of Staphylococcus aureus strains that causes blisters and desquamation of skin in scalded skin syndrome is A. enterotoxin. B. hemolysin. C. toxic shock syndrome toxin. D. exfoliative toxin.

D

6. Scarlet fever is caused by strains of A. Staphylococcus aureus. B. Staphylococcus epidermidis. C. Staphylococcus saprophyticus. D. Streptococcus pyogenes. E. Streptococcus agalactiae.

D

65. In which of the following situations would Staphylococcus epidermidis be the most likely etiologic agent? A. otitis media B. food intoxication C. urinary bladder infection D. infected IV catheter site E. conjunctivitis

D

69. Acinetobacter baumanii has become a high-profile opportunistic pathogen, causing wound infections, urinary tract infections, pneumonia and septicemia. What is the reason for its high-profile nature? A. A. baumanii has a very low infective dose and nearly everyone that contacts it gets a very serious infection. B. A. baumanii produces an exotoxin that causes servere diarrhea. C. A. baumanii is very fastidious and is difficult to culture in the laboratory. D. Many strains of A. baumanii are highly resistant to antibiotics.

D

13. All the following pertain to Staphylococcus epidermidis infections, except A. they often develop from an endogenous source. B. they typically occur after insertion of shunts and prosthetic devices. C. catheterization can introduce the organism and lead to urinary tract infection. D. the organism is coagulase negative. E. the organism produces a large number of tissue damaging enzymes and toxins.

E

18. Streptococcus pyogenes causes all the following, except A. necrotizing fasciitis. B. erysipelas. C. impetigo. D. scarlet fever. E. scalded skin syndrome.

E

20. Scarlet fever involves A. high fever. B. bright red rash on face, trunk, inner arms and legs, and tongue. C. eventual desquamation of epidermis. D. septicemia as a complication. E. All of these choices are correct.

E

24. All of the following pertain to Enterococcus faecalis, except A. normal flora of the human large intestine. B. increasingly resistant to many antimicrobics. C. cause nosocomial wound infections, urinary tract infections, and septicemias. D. can cause endocarditis. E. belong to Lancefield Group B streptococci.

E

25. The viridans streptococci are A. not entirely groupable by Lancefield serology. B. the most numerous residents of the oral cavity. C. opportunists that can cause subacute endocarditis. D. introduced to deeper body tissues by dental or surgical procedures. E. All of these choices are correct.

E

28. Disease/s caused by Streptococcus pneumoniae include A. otitis media. B. meningitis. C. lobar pneumonia. D. bronchial pneumonia. E. All of these choices are correct.

E

31. Neisseria gonorrhoeae is A. the cause of ophthalmia neonatorum. B. the cause of gonorrhea. C. called the gonococcus. D. virulent due to fimbriae and a protease that inactivates IgA. E. All of these choices are correct

E

33. All of the following pertain to Neisseria meningitidis, except A. virulence factors include a capsule, pili, endotoxin, and IgA protease. B. it causes serious meningitis. C. the reservoir is the nasopharynx of human carriers. D. it is more easily transmitted in day-care facilities, dorms, and military barracks. E. it is a common cause of bacterial pneumonia.

E

35. A positive Quellung reaction, or capsular swelling, is confirmatory for A. Neisseria meningitidis. B. Staphylococcus aureus. C. Streptococcus pyogenes. D. Branhamella (Moraxella) catarrhalis. E. Streptococcus pneumoniae.

E

39. A patient has a suspicious skin infection and a culture is taken. Which media would be appropriate to select for staphylococci? A. Nutrient agar B. Blood agar C. Chocolate agar D. macConkey agar E. Mannitol salt agar

E

5. The bright red rash and fever of scarlet fever is due to A. enterotoxins. B. hemolysins. C. toxic shock syndrome toxin. D. exfoliative toxin. E. erythrogenic toxin.

E

7. Which pathogen is the most common cause of neonatal pneumonia, sepsis, and meningitis in the United States? A. Staphylococcus aureus B. Staphylococcus epidermidis C. Staphylococcus saprophyticus D. Streptococcus pyogenes E. Streptococcus agalactiae

E