6 :: All of the following statements about the M-protein of Group A- Streptococci are correct EXCEPT?* A. The amino terminal portion (distal portion) is variable, accounting for over 80 distinct serotypes.
* B. M proteins allow streptococci to resist phagocytosis.
* C. Antibodies to M protein confer type-specific immunity.
* D. M protein is the major virulence factor of Group A streptococci
* E. M protein is the major constituent of the capsule of Group A streptococci
Correct Answer: E
7 :: Which of the following extracellular enzymes produced by Group A-streptococci is called “spreading factor”, an enzyme important in skin and soft tissue infection?* A. Streptokinase
* B. Hyaluronidase
* C. M Protein
* D. Deoxyribonuclease C
* E. None of the above
Correct Answer: D
8 :: The diagnosis of septicemia should be considered in patients who are at increased risk of blood stream infection (often secondary to local disease, such as urinary tract infection or pneumonia). All of the following are factors predisposing patients to septicemia except?* A. Underlying diseases that appear to compromise host defenses, such as diabetes, lymphoma, etc
* B. Patients with a polymorphonuclear leukocyte count less than 1000/mm3
* C. Patients with polymorphonuclear leukocyte counts of 10,000 to 20,000
* D. Long term therapy with broad-spectrum antimicrobials.
9 :: Physical findings and other factors that should suggest the presence of septicemia in a particular patient are all of the following except?* A. Shaking chills, spiking fevers
* B. Conjunctivitis
* C. Nausea, vomiting, diarrhea
* D. in elderly patients, decreased urine output or mental changes (confusion)
Correct Answer: B
10 :: It is extremely difficult to eradicate staphylococcal infection in the presence of a foreign body. Thus, infected artificial joints and infected intravenous lines often must be removed in conjunction with optimal intravenous anti-staphylococcal therapy with oxacillin or nafcillin (sometimes in combination with rifampin) in order to eradicate such staphylococcal infections (and these attempts are not always successful). Staphylococcal infection of bone may persist for many years despite what should be optimal antimicrobial therapy. The most likely reason for this tenacity of staphylococcal osteomyelitis is:?* A. The Staphylococcal pilus gene is up-regulated by oxacillin
* B. Fragments of dead bone, called "involucrum" may act as a foreign body, and may have to be removed for optimal eradication of the staphylococcal infection.
* C. Staphylococci may be perceived by the patient's immune system as a positive factor, because the staphylococci produce an extracellular enzyme, obtundokinase, which makes the patient more alert.
* D. Staphylococci are such an integral part of our normal flora that they are treated as "self" rather than "non-self", and no immune reaction to them occurs.
Correct Answer: B