Evaluation of the BacT/Alert Blood Culture System for Culturing Sterile Body Fluids other than Blood

Kim, Hye Ran; Shin, Jung Whan; Lee, Jeong Nyeo

Abstract

BACKGROUND
Many invasive and life-threatening infections are diagnosed by the culture of normally sterile body fluids. Because microorganisms are present in very low concentrations, and these infections are often caused by fastidious or slow-growing microorganisms, they may not be detected by conventional culture methods. The present study was designed to assess the performance of the BacT/Alert blood culture system in order to recover microorganism with standard aerobic and anaerobic bottles and FAN aerobic and anaerobic bottles versus conventional culture methods for culturing normally sterile body fluids other than blood. METHODS: Between February and April 2003, sterile body fluids, such as cerebrospinal fluids (CSF), pleural fluids, peritoneal fluids, continuous ambulatory peritoneal dialysate (CAPD), and other fluids submitted to the microbiology laboratory for culture were entered into the study. Only specimens with a minimum volume of 3.0 mL were included, and the specimens were divided equally among three arms of the study. All BacT/Alert bottles were monitored for up to 5 days. Conventional blood agar plate and thioglycollate broth were incubated for up to 3 days before being discarded as negative, while anaerobic cultures were maintained for a minimum of 5 days. Bacterial identification and antimicrobial susceptibility tests were performed using standard laboratory protocols. RESULTS: A total of 247 specimens (CSF 85, pleural fluids 68, peritoneal fluids 71, CAPD 17, others 6) were included in this study, with 45 isolates recovered from 43 specimens. The recovery rates for each method were standard bottles 65.1% (28/43), FAN bottles 79.1% (34/43), and conventional culture 48.9% (21/43). For CSF and peritoneal fluids, more isolates were recovered from the FAN bottles compared to the conventional culture or standard bottles. The FAN bottles recovered more coagulase negative staphylococci than those from the conventional culture or standard bottles. CONCLUSIONS: Even though the BacT/Alert system using FAN bottles improved the recovery rate for CSF and peritoneal fluids compared to either the standard bottles or conventional culture, coagulase negative staphylococci were also frequently recovered. Therefore, further evaluations are required to assess the clinical usefulness of culturing sterile body fluids using the Bact/Alert blood culture system.