Recovery of clinically important microorganisms from the BacT/Alert blood culture system does not require testing for seven days.
ABSTRACT Recently, we published a comparison of the BacT/Alert blood culture system with the BACTEC 660/730 nonradiometric blood culture system using blood inocula of 5 ml per bottle. By reanalyzing data collected during that study, we found that, for true-positive isolates causing bacteremia or fungemia, 363 (97.6%) of 376 and 341 (97.7%) of 349 isolates were recovered by the end of day 5 of testing, and 364 (97.9%) of 376 and 343 (98.3%) of 349 isolates were recovered by the end of day 6 of testing for aerobic and anaerobic bottles, respectively. Most isolates recovered on days 6 (24 of 27) and 7 (20 of 25) of testing were either contaminants or indeterminate as a cause of sepsis. When used as recommended by the manufacturer, only six (1.3%) of 464 clinically important isolates recovered on test days 6-7 would have gone undetected had testing been limited to 5 days and four (0.9%) of 464 had testing been limited to 6 days. We conclude that BacT/Alert bottles can be tested for as few as 5 days and then discarded with minimal loss of true-positive isolates and maximal reduction of contaminants.
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ABSTRACT: SUMMARY The BacT/Alert (BTA) (Bio Merieux, Durham, NC) and Isolator (ISO) (Wampole Laboratories, Cranbury, NJ) blood culture systems were evaluated for their ability to detect aerobic and facultatively anaerobic microorganisms in blood of adult patients. Eight to 10 ml of blood was inoculated into each of the aerobic BTA bottle and the ISO tube for every patient enrolled in the study. Out of 2,114 samples, 179 isolates were recovered from 89 patients. BTA detected 73.18% (131/179) of the isolates while ISO detected 78.77% (141/179) of the isolates with 51.96% (93/179) detected by both. There was no statistically significant difference in the total recovery of isolates between the two systems (P>0.05) but BTA significantly detected more Gram negative rods while ISO significantly detected more Gram positive cocci and yeasts (P