[Role of anaerobic blood culture in the simultaneous blood culture taking for the diagnosis of bacteremia].

Background: Harboring a high mortality, the incidence of sepsis is increasing; thus detection, identification and susceptibility tests of the involved microorganisms become urgent.

Methods: We reviewed the records from January 2013 until July 2014 of a total of 4110 blood culture bottles taken from adult patients in a private tertiary hospital.

Results: Growth of microorganisms was observed in 559 bottles (12.6%). We emphasize that 2648 blood cultures (60%) were taken in two paired aerobic and anaerobic bottles drawn at the same time (1324 pairs); from these, growth was observed in 182 inoculated bottles drawn from two different sites at the same time from 135 patients (13.7%). In 86 pairs of bottles with samples from 54 patients (40%), growth occurred only in the aerobic blood culture bottles. Also, growth of microorganisms was observed only in anaerobic bottles in 24 pairs (13.19%), corresponding to 21 patients (15.5%, p<0.05%). In blood cultures from 32 out of 60 patients with growth in both media (53%), microbial growth was detected first in the anaerobic bottle.

Conclusions: The usefulness of blood cultures for anaerobes for the identification of obligate anaerobic bacteremia which rarely occur is low (2.2% of patients with bacteremia); however, in 15.55% of the patients the risk of completely overlook bacteremia was present, and in 53% of patients with positive cultures, bacteremia was established earlier, and thus permitted earlier and accurate decision making.