Controlled clinical evaluation of BACTEC Plus Aerobic/F and BacT/Alert Aerobic FAN bottles for detection of bloodstream infections.

A total of 7,190 blood culture sets were obtained from adult patients with a suspected bloodstream infection. A 20-ml sample of blood was distributed equally between the aerobic FAN bottle which was monitored in the BacT/Alert system and a Plus Aerobic/F bottle which was monitored in the BACTEC 9240 system. A total of 988 positive cultures were obtained from 483 patients; however, only 453 positive cultures from 173 patients met the criteria for volume ( > or = ml per bottle) and clinical significance on the basis of concurrent case review required for data analysis. There were 25 and 68 false positives from the FAN and Plus Aerobic/F bottles, respectively. There were no statistically significant differences between systems in the number of positive cultures or septic episodes by species; however, the total number of Enterobacteriaceae and Pseudomonas aeruginosa isolates combined was significantly greater in the FAN bottle (P = 0.04). Detection times did not differ significantly between systems for positive cultures; however, episodes of Staphylococcus aureus bacteremia were detected significantly more rapidly from the FAN bottle (P = 0.005). There was no significant difference between systems in the detection of bloodstream infections in patients receiving antibiotics at the time of blood culture.

Controlled clinical comparison of two lysis-based blood culture systems, isolator and Septi-Chek Release, for detection of bloodstream infections.

A controlled clinical comparison was made of the Isolator (Wampole Laboratories, Cranbury, N.J.) and the Septi-Chek Release bottle (Roche Diagnostics, Nutley, N.J.). From 6,345 blood culture sets fulfilling minimum criteria for volume of blood cultured, 840 strains were isolated, of which only 691 (82%) were considered to be representative of bloodstream infection according to Centers for Disease Control definitions. Statistically significant differences were found between the systems for the following organisms, which were all detected more frequently in the Isolator system: Staphylococcus aureus (P = 0.0001), Alcaligenes xylosoxidans (P = 0.008), Klebsiella pneumoniae (P = 0.05), Salmonella spp. (P = 0.03), and Candida albicans (P = 0.02). The Septi-Chek Release system required a longer period of time than the Isolator system for detection of the following organisms:S. aureus (P = 0.0001), Enterococcus spp. (P = 0.0001), Enterobacter cloacae (P = 0.03), Escherichia coli (P = 0.0001), Klebsiella oxytoca (P = 0.03), K. pneumoniae (P = 0.02), Pseudomonas aeruginosa (P = 0.002), and C. albicans (P = 0.005). There were 430 episodes of bloodstream infections identified in the study; of these episodes, only those due to S. aureus were detected significantly more frequently (P = 0.0001) by the Isolator system than by the Septi-Chek Release system. However, episodes of bloodstream infections due to S. aureus, Staphylococcus epidermidis, Enterococcus spp., and E. coli were detected significantly faster by the Isolator system.

Comparison of conventional and revised isolator blood culture tubes.

A paired clinical study compared bacterial and fungal recovery from 4,553 blood cultures processed by the conventional Isolator (Du Pont Co.) and a revised Isolator consisting of a single-stoppered, round-bottom tube containing the same ingredients as the conventional tube except for an inert fluorochemical. Excluding contaminants, there were 425 positive blood cultures with 450 isolates representing 208 patients. There were no statistically significant differences between systems in the number of positive cultures or patients with positive cultures for each organism group studied, nor were there any statistically significant differences between systems in the time required for detection of positive cultures.