BOC Questions Flashcards
249
MLS
ONLY
Which organism is the most common anaerobic bacteria isolated from infectious processes of
Soft tissue and anaerobic bacteremia?
A.Bacteroides fragilis
b Fusobacterium nucleatum
C.Porphyromonas asaccharolytica
d .Clostridium perfringens
A
247 A patient has a suspected diagnosis of subacute bacterial endocarditis. His blood cultures grow ONLY non-spore-forming pleomorphic gram-positive bacilli only in the anaerobic bottle. What test(s) will give a presumptive identification of this microorganism?
MLS
A.beta-hemolysis and oxidase
B. catalase and spot indole
C.esculin hydrolysis
d .hydrolysis of gelatin
B
249 Which organism is the most common anaerobic bacteria isolated from infectious processes of MLS ONy Soft tissue and anaerobic bacteremia?
A.Bacteroides fragilis
b .Fusobacterium nucleatum
c .Porphyromonas asaccharolytica
d .Clostridium perfringens
A
245 A stool sample is sent to the laboratory for culture to rule out Clostridium difficile. What media should the microbiologist use and what is the appearance of the organisms on this media?
A.BBE: colonies turn black
B.Brucella agar: red pigmented colonies
C.CCFA: yellow, ground glass colonies
d. CNA: double zone hemolytic colonies
C
235 Propionibacterium acnes is most often associated with:
A. normal oral flora
B. post-antibiotic diarrhea
C.tooth decay
D.blood culture contamination
D
231 Anaerobic infections differ from aerobic infections in which of the following?
a .they usually respond favorably with aminoglycoside therapy
b .they usually arise from exogenous sources
C.they are usually polymicrobic
D.Gram stains of specimens are less helpful in diagnosis
C
227 A branching gram-positive, partially acid-fast organism is isolated from a bronchial washing on a 63-year-old woman receiving chemotherapy. The organism does not hydrolyze casein, tyrosine or xanthine. The most likely identification is:
A.Actinomadura madurae
B.Nocardia caviae
C.Streptomyces somaliensis
D. Nocardia asteroides
D
226 Fluid from a cutaneous black lesion was submitted for routine bacterial culture. After 18 hours of incubation at 35°C there was no growth on MacConkey agar, but 3+ growth on sheep blood agar. The colonies were nonhemolytic, nonmotile, 4-5 mm in diameter and off-white with a ground glass appearance. Each colony had an irregular edge with comma-shaped outgrowths that stood up like “beaten egg whites” when gently lifted with an inoculating needle. A Gram stain of a typical colony showed large, gram-positive rectangular bacilli. The organism is most likely:
A.Clostridium perfringens
B.Aeromonas hydrophila
C.Bacillus anthracis
D.Mycobacterium marinum
C
223 Establishing the pathogenicity of a microorganism isolated from a child’s throat and identified as
Corynebacterium diphtheria would depend upon:
A.the morphological appearance as revealed by Gram stain
B.the type of hemolysis on blood agar
C.positive toxigenicity test
D.the appearance of growth on Tinsdale tellurite agar
C
185 A gram-negative bacillus with bipolar staining was isolated from a wound infection caused by a bite from a pet cat. The following characteristic reactions were seen:
oxidase:
glucose OF:
catalase:
motility:
positive
fermentative
positive
negative
MacConkey agar: no growth
Which of the following is the most likely organism?
A.Pseudomonas aeruginosa a
B.Pasteurella multocida
C.Aeromonas hydrophila
d .Vibrio cholerae
B
180 An isolate on chocolate agar from a patient with epiglottitis was suggestive of Haemophilus species. Additional testing showed that the isolate required NAD for growth and was nonhemolytic. The organism is most likely Haemophilus:
a .haemolyticus
b .ducreyi
c .influenzae
d .parainfluenzae
D
A 64-year-old male with lymphoma has a positive blood culture at 18 hours incubation. The y organism is a nonlactose fermenting gram-negative bacillus on MacConkey agar. Further testing gives the following reactions:
154
oxidase: neg
TSI: AlK / Acid , no hydrogen sulfide
motility: pos
indole: pos
citrate: pos
ornithine decarboxylase: neg
urea: pos
phenylalanine deaminase: pos
VP:neg
The genus is:
a .Proteus
B.Morganella
C.Providencia
D.Serratia
C
125 A yellow colony from a wound culture tested catalase-positive and coagulase-negative. The organism stained as gram-positive cocci in clusters. Which of the following tests would differentiate between a coagulase-negative Staphylococcus and Micrococcus?
A.novobiocin susceptibility
b .furazolidone (100 µg/disk) susceptibility
C.leucine aminopeptidase production
d .bile esculin
B
124 An outbreak of Staphylococcus aureus has occurred in a hospital nursery. In order to establish the epidemiological source of the outbreak, the most commonly used typing method is:
MLS
ONLY
A.pulsed-field gel electrophoresis
B.bserological typing
c .coagulase testing
d .catalase testing
A
107 Which of the 2 different antimicrobial agents listed below are commonly used and may result in synergistic action in the treatment of endocarditis caused by Enterococcus faecalis?
a an aminoglycoside and a macrolide
a penicillin derivative and an aminoglycoside
a cell membrane active agent and nalidixic acid
d a macrolide and a penicillin derivative
B
