BOC Microbiology- Aerobic Gram-Positive Cocci

novobiocin susceptibility

A urine gram stain shows gram positive cocci in clusters. The organism tested catalase positive. To speciate this organism from culture, the technician should perform a coagulase test and what?

abiotrophia defectiva

The gram stain from a blood culture shows gram positive cocci in chains. No growth occurs on blood agar plates incubated both aerobically and anaerobically. Additional testing should be done to detect the presence of what?

bile solubility

Viridans streptococci can be differentiated from streptococcus pneumonia by what?

coagulase

A reliable test for distinguishing Staphylococcus aureus from other staphylococci is what?

Streptococcus pneumoniae

The optochin (ethylhydrocupreine hydrochloride) disk is used for the identification of what?

pneumococci

In the optochin susceptibility test, if there is a zone of inhibition of 19-30 mm surrounding the disk following overnight incubation at 37 degrees C, the colony most likely consists of what?

glomerulonephritits, rheumatic fever

What 2 diseases are usually preceded by infection with beta-hemolytic streptococci?

one type of bacterial food poisoning

The enterotoxin produced by certain strains of hemolytic, coagulase positive staphylococcus aureus causes what?

group D streptococcus

A gamma-hemolytic Streptococcus that blackens bile esculin agar but does not grow in 6.5% NaCl broth is most likely what?

catalase production and coagulase test

Gram stain examination from a blood culture bottle shows dark blue, spherical organisms in clusters. Growth on sheep blood agar shows, small, round, pale yellow colonies. Further tests should include what?

bile esculin, PYR, bacitracian, and hippurate

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 what?

in the genera Granulicatella and Abiotrophia

"Nutritionally deficient" streptococci are what?

perform a Streptococcus group typing

After a 24 hour blood culture from a newborn grows catalase-negative, gram positive cocci. The bacterial colonies are small, translucent and beta-hemolytic on a blood agar plate. Biochemical test results of a pure culture are: Bacitracian-resistant; CAMP reaction-positive; bile esculin-not hydrolyzed; 6.5% NaCl broth-no growth. Assuming that all controls react properly and reactions are verified, the next step would be what?

growth in 6.5% NaCl broth

A beta-hemolytic streptococcus that has been isolated from an ear culture grows up to the edge of a 0.04 unit bacitracin disk. What test would help to determine if the organism is Enterococcus?

group B streptococci

The organism most commonly associated with neonatal purulent meningitis is what?

Streptococcus pyogenes

An important cause of acute exudative pharyngitis is what?

a penicillin derivative and an aminoglycoside

What two different antimicrobial agents listed below are commonly used and may result in synergistic action in the treatment of endocarditis caused by Enterococcus faecalis?

growth of 6800 colonies/mL of a streptococcus species, esculin hydrolysis and NaCl growth test to follow

A catheterized urine is inoculated onto blood and MacConkey agar using a 0.01 mL loop. After 48 hours, 68 colonies of a small translucent nonhemolytic organism grew on blood agar but not MacConkey. Testing reveals small gram positive, catalase negative cocci. The preliminary report and follow up testing would be what?

acute glomerulonephritis

Children who have infections with beta hemolytic streptococci can develop what?

Streptococcus agalactiae

A gram positive coccus isolated from a blood culture has the following characteristics:
optochin susceptibility-negative; bacitracin susceptibility-negative; bile esculin hydrolysis-negative; hippurate hydrolysis-positive; catalase-negative.
The organism is most likely what?

group A

A beta hemolytic streptococci that is bacitracin sensitive and CAMP negative is what?

group B

A beta hemolytic Streptococci that is bacitracin resistant and CAMP positive is what?

latex antigen typing

Group B, beta hemolytic streptococci may be distinguished from other hemolytic streptococci by what procedure?

enterococci often show more antibiotic resistance than group D streptococci

It is important to differentiate between Enterococcus and group D streptococci because of why?

bile solubility

Streptococcus pneumonia can be differentiated best from the viridns group of streptococci by what?

the type of hemolysis

Characteristically, enterococci are what?

do a tube coagulase test to confirm the slide test

A beta hemolytic, catalase positive, gram positive coccus is coagulase negative by the slide coagulase test. What is the most appropriate action in identification of this organism?

hydrolysis of sodium hippurate

Which of the following would best differentiate Streptococcus agalactiae from Streptococcus pyogenes?

coagulase production

The most critical distinction between Staphylococcus aureus and other Staphylococcus is what?

Streptococcus pyogenes

What organism, to date, is considered universally susceptible to penicillin?

latex antigen typing

A beta hemolytic gram positive coccus was isolated from the cerebrospinal fluid of a 2 day old infant with signs of meningitis. The isolate grew on sheep blood agar under aerobic conditions and was resistant to a bacitracin disc. What should be performed for the identification of the organism?

2-6 hours

How many hours after eating contaminated food do initial symptoms of Staphylococcal food poisoning typically occur?

there has been a break in proper skin preparation before drawing blood for culture

During the past month, Staphylococcus epidermidis has been isolated from blood cultures at 2-3 times the rate from the previous year. The most logical explanation for the increase in the isolates is what?

pulsed-field gel electrophoresis

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 what?

furazolidone (100 ug/disk) susceptibility

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?

Micrococcus luteus

A light yellow colony from a skin lesion grew aerobically and tested as catalase positive and coagulase negative. The organism gram stained as positive cocci in clusters. The organism was modified oxidase positive, bacitracin susceptible and resistant to lysostaphin. What is the identification of this organism?

CAMP test and S agalactiae

An isolate of an unknown beta hemolytic Streptococcus is streaked perpendicular to a streak of beta lysine producing Staph aureus. After incubation a zone of arrowhead hemolysis is noted at the interface of the 2 streaks. What is the name of the test and the presumptive identification of the unknown streptococcus?

Enterococcus faecalis

Which of the following may be used as a positive quality control organism for the bile esculin test?