Comparative evaluation of blood culture using the Vital automated system and the Becton-Dickinson Septi-Chek BHI-S biphasic and Sch bottles.

A comparative study was performed using 1,168 aerobic and anaerobic blood culture pairs from 395 patients, during which 5-10 mL of blood were collected in both Septi-Chek BHI-S biphasic and Septi-Chek Sch bottles (Becton-Dickinson, Meylan, France) and Vital AER and Vital Ana bottles (bioMérieux, Marcy-l'Etoile, France). The bottles were analyzed by using a 7-day protocol for Vital and a 12-day protocol for Septi-Chek. The Vital bottles revealed negative were all subcultured at the end of the protocol. Of the 374 positive Septi-Chek bottles, only 202 bottles gave a positive subculture. Of the 245 positive Vital bottles, 223 bottles led to the isolation of a microorganism. Thirty-five septic episodes were detected by Septi-Chek compared to 38 by the Vital system (only clinically significant isolates were taken into consideration). Four septic episodes were detected by Vital only (one episode implicating coagulase-negative Staphylococcus, one Streptococcus pneumoniae, one Pseudomonas aeruginosa and one Candida albicans, involving a total of 15 bottles). One septic episode implicating Bacteroides fragilis was detected by Septi-Chek only (five bottles). Among the negative Vital bottles, only six bottles gave a positive terminal subculture. This study validates the reliability of the Vital system to detect positive blood cultures.