Controlled comparison of the BacT/Alert and BACTEC 660/730 nonradiometric blood culture systems

Abstract

In a collaborative study at three university hospitals, the recovery of microorganisms and the speed of detection of microbial growth by the BacT/Alert (Organon Teknika Corporation, Durham, N.C.) and BACTEC 660/730 (Becton-Dickinson Diagnostic Instrument Systems, Sparks, Md.) nonradiometric blood culture systems were compared. A total of 5,918 comparisons were made between BacT/Alert aerobic and BACTEC NR 6A bottles and 5,992 comparisons were made between BacT/Alert anaerobic and BACTEC NR 7A bottles. Each bottle was inoculated with 5 ml of blood. The overall recoveries of microorganisms from the two aerobic bottles were comparable; members of the family Enterobacteriaceae were recovered more often from BacT/Alert aerobic bottles alone (P < 0.001). The overall recoveries of microorganisms from the two anaerobic bottles were not significantly different. Growth of Staphylococcus aureus (P < 0.001), coagulasenegative staphylococci (P < 0.01), streptococci (P < 0.001), Escherichia coli (P < 0.01), other members of the family Enterobacteriaceae (P < 0.02), and Pseudomonas aeruginosa (P < 0.05) was detected earlier in BacT/Alert aerobic bottles. Growth of S. aureus (P < 0.001), coagulase-negative staphylococci (P < 0.05), enterococci (P < 0.01), Streptococcus pneumoniae (P < 0.02), viridans group streptococci (P < 0.05), E. coli (P < 0.001), KlebsieUa pneumoniae (P < 0.01), and other members of the family Enterobacteriaceae (P < 0.001) was detected earlier in BacT/Alert anaerobic bottles. In a system-versus-system comparison, more grampositive cocci were recovered from the BACTEC system alone (P < 0.05), and more members of the family Enterobacteriaceae were recovered from the BacT/Alert system alone (P < 0.001). As a system, the BacT/Alert system detected growth of S. aureus (P < 0.001), coagulase-negative staphylococci (P < 0.01), streptococci (P < 0.001), E. coli (P < 0.001), other members of the family Enterobacteriaceae (P < 0.001), and P. aeruginosa (P < 0.05) earlier than the BACTEC system did. Significantly fewer (40 versus 1,183) false-positive results occurred with the BacT/Alert system. We conclude that the BacT/Alert and BACTEC 660/730 nonradiometric systems are comparable for recovering clinically significant microorganisms from adult patients with bacteremia or fungemia, but that the BacT/Alert system detects microbial growth earlier than the BACTEC system does, with significantly fewer false-positive results.

Evaluation of the BacT/Alert and VITAL blood culture systems for the diagnosis of bacteremia

“…In a large controlled clinical comparison of VITAL and BACTEC NR-600 blood culture systems for the detection of sepsis in children [5], the BACTEC PEDS PLUS bottle performed significantly better than the VITAL AER bottle in detecting the growth of bacteria and yeast from children. When the authors evaluated cultures that had a volume advantage in one system over the other, PEDS PLUS bottles retained a statistical advantage even when VITAL AER bottles received more blood.…”

“…While in our study standard media flacT/Alert bottles were used in comparison with the VITAL bottles, Zaidi et a1 [5] compared VITAL AER bottles with resin-containing PEDS PLUS bottles. Although it is suggested that resin-containing media are superior for detecting microorganisms, especially for patients on antimicrobial therapy, Zaidi et a1 (51 found that PEDS PLUS medium was also better at detecting Staphylococci and all microorganisms combined even for patients not on antimicrobial therapy.…”

“…In our study we found that the mean time to detection in hours favored the BacT/Alert system, with results approaching statistical significance at the 5% level. Zaidi et a1 [5] concluded that although the VITAL system in general was faster at detecting microbial growth, the difference of only 1 h is not impressive, considering that the VITAL system is a continuously monitoring system and that growth in the semiautomated BACTEC NR-660 syste~n is monitored only once or twice a day.…”

“…The BacT , and, recently, the VITAL system has been described in comparison with the Bactec NR-660 [5]. The objective of this study was to evaluate and compare BacT/Alert and VITAL blood culture systems to find out which of them provides beccer detection of bacteremia.…”

Comparison of BacT/Alert and BACTEC NR 860 blood culture systems in a laboratory not continuously staffed

“…These differences were not statistically significant. Wilson et al did not find a difference in staphylococcal isolation when comparing BacT/Alert and BACTEC NR 660/730 [2]. However, BacT/Alert was less effective in recovering Staphylococcus aureus isolates in a trial comparing BacT/Alert with Difco ESP [9].…”