| Question | Answer |
| A gram-pos coccus isolated from a blood culture has the following characteristics: optochin suscept-neg, bacitracin suscept-neg, bile esculin hydrolysis-neg, hippurate hydrolysis-pos, catalase-neg. The organism is MOST likely: | Streptococcus agalactiae |
| A beta-hemolytic streptococcus that has been isolated from an ear culture grows up to the edge of a 0.04 unit bacitracin disk. Which tests would help to determine if the organism is Entercoccus? | growth in 6.5% NaCl broth |
| The organism MOST commonly associated with neonatal purulent meningitis is: | group B streptococci |
| Children who have infections with beta-hemolytic streptococci can develop: | acute glomerulonephritis |
| Streptococcus pneumonia can be differentiated best from the viridans group of streptococci by: | bile solubility |
| Gram-positive cocci in chains are seen on a Gram stain from a blood culture. The organism grows as a beta-hemolytic colony. Further tests that could be performed include: | bile esculin, PYR, bacitracin, and hippurate |
| Gram stain examination from a blog culture bottle shows dark blue, spherical organisms in clusters. Growth on sheep blood agar shows small, round, pale yellow colonies. Further tests should include: | catalase production and coagulase test |
| Which would best differentiate Streptococcus agalactiae from Streptococcus pyogenes? | hydrolysis of sodium hippurate |
| The enterotoxin produced by certain strains of hemolytic, coagulase positive Staphylococcus aureus: | causes one type of bacterial food poisoning |
| The optochin (ethylhydrocupreine hydrochloride) disk is used for the identification of: | Streptococcus pneumoniae |
| Which 2 diseases are usually preceded by infection with beta-hemolytic streptococci? | glomerulonephritis and rheumatic fever |
| Characteristically, enterococci are: | relatively resistant to penicillin |
| A beta-hemolytic streptococci that is bacitracin-sensitive and CAMP-negative is: | group A |
| An important cause of acute exudative pharyngitis is: | Streptococcus pyogenes |
| During the past month, Staphylococcus epidermis has been isolated from blood cultures at 2-3 times the rate from the previous year. The MOST logical explanation for the increase in these isolates is: | there has been a break in proper skin preparation before drawing blood for culture |
| A urine Gram stain shows gram-positive cocci in clusters. The organisms tested catalase positive. To SPECIATE this organism form culture, the tech should perform a coagulase test and a/an: | novobiocin susceptibility |
| An isolate of unknown beta-hemolytic Strep is streaked perpendicular to a streak of beta-lysin producing S. aureus. Zone of arrowhead hemolysis is noted. What is the name of the test and presumptive ID of unknown strep? | CAMP test and S. agalactiae |
| A gamma-hemolytic Streptococcus that blackens bile esculin agar but does not grow in 6.5% NaCl broth is MOST likely: | group D Streptococcus |
| Which organisms is, to date, considered universally susceptible to penicillin: | Streptococcus pyogenes |
| The MOST critical distinction between Staphylococcus aureus and other Staphylococcus is: | coagulase production |
| A beta-hemolytic gram-pos coccus was isolated from CSF of a 2 day old infant w/signs of meningitis. This isolate grew on sheep blood agar under aerobic conditions and was resistant to a bacitracin disc. What should be performed for the identification? | latex antigen testing |
| Which of the 2 different antimicrobial agents are commonly used and may results in synergistic action in the treatment of endocarditis caused by Enterococcus faecalis? | a penicillin derivative and an aminoglycoside |
| Group B, beta-hemolytic streptococci may be distinguished from other hemolytic streptococci by which procedure? | latex antigen typing |
| Which is the MOST frequent cause of prosthetic heart valve infections occurring within 2-3 months after surgery is: | Staphylococcus epidermidis |
| A reliable test for distinguishing Staphylococcus aureus from other staphylococcus is: | coagulase |
| A beta-hemolytic, catalase positive, gram-positive coccus is coagulase negative by the slide coagulase test. Which is the MOST appropriate action in identification of this organism? | do a tube coagulase test to confirm the slide test |
| A light yellow colony from a skin lesion grew aerobically and was catalase positive and coag neg. Gram stained as positive cocci in clusters, modified oxidase positive, bacitracin susceptible and resistant to lysostaphin. The identification is? | Micrococcus luteus |
| Which organism may be used as a positive quality control organism for the bile esculin test? | Enterococcus faecalis |
| A beta-hemolytic Streptococcus that is bacitracin-resistant and CAMP-positive is" | group B |
| In the optochin susceptibility test, if there is a zone of inhibition of 19-30mm surrounding the disk following overnight incubation at 37C, the colony MOST likely consist of: | pneumococci |
| How many hours after eating contaminated food do initial symptoms of staphylococcal food poisoning typically occur? | 2-6 hours |
| It is important to differentiate between Enterococcus and group D strep because: | enterococci often show more antibiotic resistance than group D streptococci |
| A yellow colony from a wound culture tested catalase-positive and coagulase-negative. The organism stained as gram-positive cocci in clusters. Which tests would differentiate between coat-neg staph and Micrococcus? | furazolidone susceptibility |
| Viridans streptococci can be differentiated from Streptococcus pneumoniae by: | bile solubility |
| 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: | pulsed-field ges electrophoresis |
| "Nutritionally deficient" streptococci are: | in the genera Granulicatella and Abiotrophia |
| The Gram stain from a blood culture shows gram-pos cocci in chains. No growth occurs on blood agar plates incubated aerobically and anaerobically. Additional testing should be done to detect the presence of: | Abiotrophia defectiva |
