Question

A four-year-old boy, evan, was admitted to the hospital to evaluate and treat persistent pain in the rectal area. his problem began about one week earlier with ill-defined pain in the same region. he had a white blood cell count of 24,900 with 87% granulocytes (neutrophils). an abdominal computed tomography scan revealed an abscess (walled-off region of infectious bacteria) next to his rectum. a needle aspiration of the abscess drained 20 milliliters of yellowish, foul-smelling fluid. the specimen was plated on blood agar under aerobic conditions, but the culture was negative despite evidence of bacteria in the abscess drainage. (blood agar is a rich medium containing 5% sheep red blood cells.) which statement regarding specimen collection is false?

a) samples from both sterile and nonsterile body sites should be plated on selective media.
b) sterile body site samples are easily contaminated by normal flora in the collection process.
c) internal abscesses should be collected under conditions that allow the survival of anaerobic pathogens.
d) specimen collection procedures are generally divided into those for sterile and nonsterile body sites.

Answer 1

The false statement regarding specimen collection is that 'sterile body site samples are easily contaminated by normal flora in the collection process.' Sterile body sites typically do not contain normal flora and are less prone to such contamination. The other options provided are true regarding specimen collection protocols.

Step-by-step explanation:

Understanding Specimen Collection and Culture Procedures

A student asked about a four-year-old boy named Evan who was admitted to the hospital with persistent rectal pain and found to have an abscess containing bacteria. Despite evidence of bacteria, the culture was negative when the aspirated fluid was plated on blood agar under aerobic conditions. The question asks which statement regarding specimen collection is false, with four options provided.

The false statement is: 'b) sterile body site samples are easily contaminated by normal flora in the collection process.' This statement is incorrect because samples from sterile body sites, such as internal abscesses, typically don't contain normal flora; therefore, they are less likely to be contaminated by normal flora during the collection process. Options a), c), and d) all reflect true aspects of specimen collection and handling.

It is also worth noting that because the culture was performed under aerobic conditions and the specimen was from an abscess, which is often an anaerobic environment, the failure to culture bacteria could be due to the absence of the necessary anaerobic conditions. Therefore, internal abscesses should be collected under conditions that allow the survival of anaerobic pathogens as per option c).