Deck 40: Overview and General Considerations

Question 1

The final fill of the anaerobe jar prepared by the evacuation-replacement method consists of

A)20% to 30% nitrogen, 5% to 10% hydrogen, and 70% to 80% CO₂.
B)80% to 90% oxygen, 5% to 10% hydrogen, and 5% to 10% CO₂.
C)80% to 90% nitrogen, 5% to 10% hydrogen, and 5% to 10% CO₂.
D)80% to 90% nitrogen, 5% to 10% oxygen, and 5% to 10% CO₂.

Answer 1

C
An alternative to the commercial anaerobic devices available, the "evacuation-replacement" method can be used. Air is removed from a sealed jar by drawing a vacuum of 25 inches (62.5 cm) of mercury. This process is repeated two times, filling the jar with an oxygen-free gas, such as nitrogen, between evacuations. The final fill of the jar is made with a gas mixture containing 80% to 90% nitrogen, 5% to 10% hydrogen, and 5% to 10% CO₂.

Question 2

Feces in a sterile specimen cup

A)Acceptable
B)Not acceptable

Answer 2

B
Because indigenous anaerobes are often present in large numbers as normal flora on mucosal surfaces, even minimal contamination of a specimen can give misleading results. Specimens that are likely to be contaminated are unacceptable for anaerobic culture.

Question 3

Tissue biopsy taken from a puncture wound

A)Acceptable
B)Not acceptable

Answer 3

A
Because indigenous anaerobes are often present in large numbers as normal flora on mucosal surfaces, even minimal contamination of a specimen can give misleading results. In general, material for anaerobic culture is best obtained by tissue biopsy or by aspiration using a needle and syringe.

Question 4

Bronchial washing collected with double lumen plugged catheter

A)Acceptable
B)Not acceptable

Question 5

Urine via percutaneous aspiration

A)Acceptable
B)Not acceptable

Question 6

Aspiration of peritoneal fluid using a needle and syringe

A)Acceptable
B)Not acceptable

Question 7

Nasopharyngeal swab

A)Acceptable
B)Not acceptable

Question 8

Percutaneous lung aspirate

A)Acceptable
B)Not acceptable

Question 9

Pre-reduced, anaerobically sterilized (PRAS) media

A)are produced, packaged, shipped, and stored under anaerobic conditions.
B)have a short shelf life of only 2 weeks.
C)enable the culture to be incubated in the regular incubator under aerobic conditions.
D)All of the above are correct.

Question 10

Actinomyces spp., Bifidobacterium spp., and Clostridium spp.can be described as

A)aerotolerant organisms that can grow in the presence of either reduced or atmospheric oxygen but grow best under microaerobic conditions.
B)strictly anaerobic organisms that cannot grow in the presence of either reduced or atmospheric oxygen but grow only under anaerobic conditions.
C)microaerophilic organisms that can grow in the presence of either reduced or atmospheric oxygen but grow best under anaerobic conditions.
D)facultatively anaerobic organisms that grow in the presence or absence of atmospheric oxygen.

Question 11

Cervical swab

A)Acceptable
B)Not acceptable

Question 12

Expectorated sputum

A)Acceptable
B)Not acceptable

Question 13

Recapping a syringe and transporting the needle and syringe to the laboratory ensures the preservation of the anaerobic nature of this type of specimen and
A)is the method of

A)choice for transporting specimens for anaerobic culture.
B)is not acceptable for transporting specimens for anaerobic culture because of safety concerns involving needlestick injuries.
C)is rapidly replacing other methods of transporting specimens for anaerobic culture because of the effective preservation of the anaerobic nature of this type of specimen.
D)is the method of choice for transporting fluid and other aspirated specimens for anaerobic culture.

Question 14

During specimen collection, an important thing to remember when handling a collection device with an oxygen-free atmosphere is

A)to take care not to tip the container.
B)to hold the collected specimen in the refrigerator until processing.
C)to hold the collected specimen in the incubator until processing.
D)to avoid opening the container in an aerobic atmosphere.

Question 15

When activating a hydrogen and CO₂ generator system used for creating an anaerobic atmosphere, indications that the catalyst and generator envelope are functioning properly include

A)production of heat within a few minutes.
B)development of moisture on the walls of the jar.
C)a change in color of the methylene blue or resazurin indicator.
D)All of the above are correct.

Question 16

Urine via catheter

A)Acceptable
B)Not acceptable

Question 17

Rectal swab

A)Acceptable
B)Not acceptable