Culture, Blood

Blood Culture Methodologies and Reporting

When the instrument indicates that a culture has become positive, a Gram's stain of the positive bottle is performed, and subcultures are made to appropriate media. Initial, first-time positive blood cultures are immediately called to the ordering physiciant. Subsequent, repeat positives are not called unless the Gram's stain indicates a different organism(s).

Blood Cultures for Acid Fast Bacilli (Mycobacterium sp.) are similarly monitored by the BacT/Alert^® MB system. Negative results are updated automatically to the LIS and Clinical Workstations weekly; cultures are incubated for six weeks before being given a final result of Negative.

Cultures for "Rare Pathogens" are set up using one routine aerobic BacT/Alert^® bottle and the Wampole Isolator^™ system. The Isolator tube contains lytic agents, and is especially useful for recovering intracellular pathogens and dimorphic fungi. The Rare Pathogen culture type is to be used only when the organisms listed above are suspected. The Isolator tube is inoculated directly onto selective &/or enriched media specific for the organism(s) suspected, therefore it is essential that the laboratory is informed of the suspect organism at the time of ordering. Incubation times for "Rare Pathogen" cultures depends upon the organism being sought, but most are held three weeks. Call the Bacteriology Laboratory at 966-4053 for more information.