A comparison of two methods of processing blood cultures in a community hospital

Two different methods of processing blood cultures were compared at a community hospital. A day three "blind" subculture and five days of observation for visible growth was used during one year (Phase I), compared with a day five "blind" subculture and seven days of observation for visible growth during the second twelve-month period (Phase II). Phase II was not associated with an increased number of probable pathogens isolated from blood cultures, compared with the earlier "blind" subculture and shorter observation for visible growth used during Phase I. Instead, the later "blind" subculture and longer observation for visible growth yielded a significantly greater number of probable blood culture contaminants. Recommendations for processing of blood cultures developed at referral centers may not be applicable to community hospitals, and the timing of "blind" subcultures and duration of observation for visible growth should be based on the unique patient population characteristics of each hospital.