Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1409 page)

   Submission of specimens >7 days after onset of acute infection is associated with decreased sensitivity.

Suggested Reading

Carr MJ, Kajon AE, Lu X, et al. Deaths associated with human adenovirus-14p1 infections, Europe, 2009–2010.
Emerg Infect Dis.
[serial on the Internet]. 2011 Aug [date cited]. http:// dx.doi.org/10.3201/1708.101760

RESPIRATORY CULTURE, RULE OUT BACTERIAL PATHOGENS

   Definition

   Structures adjacent to the respiratory tract, like the sinuses, are usually sterile or only transiently contaminated. They may become infected, often as a superinfection complicating upper respiratory viral infection. Cultures may be considered in patients who present with unusually severe signs and symptoms consistent with sinusitis, otitis media, or other pararespiratory infection, or when symptoms persist for more than 7 days.

   The common bacterial pathogens are most commonly derived from the endogenous flora, including
Moraxella catarrhalis
,
Streptococcus pneumoniae
,
Haemophilus influenzae
, and
Staphylococcus aureus
. Anaerobic bacteria have been implicated, but usually with chronic infection or acute infection associated with trauma. Opportunistic molds, such as
Mucor
species, may cause severe, invasive upper respiratory tract infections in immunocompromised patients, especially in patients with DM.

   Special Collection and Transport Instructions

   Swab specimens should be considered unacceptable for culture, except for those collected by direct visualization by an otolaryngologist. Swab specimens are not optimal for isolation of anaerobic pathogens in chronic infections or acute abscesses.

   Pus collected by surgical aspiration or drainage or by sinus aspiration should be transported to the laboratory under anaerobic transport conditions as quickly as possible.

   Use

   Specimens are typically inoculated onto SBA and chocolate and MacConkey agar. Anaerobic media are inoculated if requested.

   
Turnaround time:
Cultures are examined for at least 48 hours. Several days are required for isolation and identification, susceptibility testing, and further characterization of isolates.

   Interpretation

   
Expected results:
No growth, but light growth of endogenous respiratory flora is common.