Question

You have isolated a coagulase-negative staphylococcus species (CNS) from a urine specimen. What should be done next?

	A.	No further testing is necessary.
	B.	DNase should be done to confirm the coagulase result.
	C.	Inoculate a blood agar and observe for staphyloxanthin and α toxin.
	D.	Do a novobiocin susceptibility test.

Media which contain substances such as antibiotics, dyes, and other compounds to inhibit the growth of certain types of bacteria are called ________ media.

	A.	differential
	B.	defined
	C.	enriched
	D.	selective

Which of the following can be used to determine the oxygen requirements of an organism?

	A.	Fluid thioglycollate medium
	B.	Blood agar
	C.	Nutrient agar
	D.	Nutrient gelatin

Which of the following is NOT a product of the reaction catalyzed by tryptophanase?

	A.	Pyruvic acid
	B.	Indole
	C.	Tryptophan
	D.	Ammonia

Of the following choices, what two species could be distinguished with Kligler's iron agar?

	A.	gram- E. coli and gram- Salmonella
	B.	gram- E. coli and gram+ S. aureus
	C.	gram+ Streptococcus and gram+ Staphylococcus
	D.	None of these could be distinguished by KIA

Answer 1

1) You have isolated a coagulase-negative staphylococcus species (CNS) from a urine specimen. What should be done next?

The correct answer is

(D) do a novobiocin susceptibility test

when coagulase negative staphylococcus is isolated from a urine sample,laboratory must further identify that isolate and find out is this a true pathogen (Staphylococcus saprophyticus-novobiocin resistant) or a contaminant (i.e. Staphylococcus epidermidis-novobiocin sensitive), to decide on the next course of management.

2) Media which contain substances such as antibiotics, dyes, and other compounds to inhibit the growth of certain types of bacteria are called ________ media.

The correct answer is

(D) Selective

Selective media with the help of antibiotics and dyes allow certain types of organisms to grow, and inhibit the growth of other organisms.

3) Which of the following can be used to determine the oxygen requirements of an organism?

The correct answer is

(A) fluid thioglycollate medium

Fluid Thioglycolate medium is a multipurpose, enriched, differential medium used primarily to determine the oxygen requirements of organisms.

4) Which of the following is NOT a product of the reaction catalyzed by tryptophanase?

The correct answer is

(C) Tryptophan

The three producs include pyruvate, indole and ammonia and Tryptophan is not the product.

5) Of the following choices, what two species could be distinguished with Kligler's iron agar?

The correct answer is

(C) gram+ streptococcus and gram+staphylococcus

The kligler's iron agar test is recommended for the differential identification of gram-negative enteric bacilli from clinical and non clinical samples and not the gram positive bacilli.