Evaluation of the efficacy of reincubation and subsequent subculture of initially positive blood cultures in the detection of additional clinically significant isolates.

Polymicrobial bacteremias are associated with higher mortality than are unimicrobial bacteremias, and their incidence appears to be increasing. Other researchers have recently shown that the prevalence of polymicrobial bacteremias may be underestimated when blood cultures are not evaluated further after identification of an initial isolate. We investigated this possibility by reincubating and further subculturing blood cultures initially positive for a single organism. We failed to show a clinically important increase in recovery of multiple isolates.