Contribution of the BacT/Alert MB Mycobacterium Bottle to Bloodstream Infection Surveillance in Thailand: Added Yield for Burkholderia pseudomallei

Abstract

Community-acquired bloodstream infections cause substantial morbidity and mortality worldwide, but microbiology capacity and surveillance limitations have challenged good descriptions of pathogen distribution in many regions, including Southeast Asia. Active surveillance for bloodstream infections has been conducted in two rural Thailand provinces for >7 years. Blood specimens were divided into two culture bottles, one optimized for aerobic growth (F bottle) and a second for enhanced growth of mycobacteria (MB bottle), and processed with the BactT/Alert 3D system. Because the routine use of MB culture bottles is resource intensive (expensive and requires prolonged incubation), we assessed the added yield of MB bottles by comparing the proportion of pathogens detected by MB versus that by F bottles from 2005 to 2012. Of 63,066 blood cultures, 7,296 (12%) were positive for at least one pathogen; the most common pathogens wereEscherichia coli(28%),Burkholderia pseudomallei(11%),Klebsiella pneumoniae(9%), andStaphylococcus aureus(6%). Two bottles improved the yield overall, but the added yield attributable to the MB bottles was limited to a few pathogens. In addition to the detection of mycobacteria and some fungi, MB bottles improved the detection ofB. pseudomallei(27% [MB] versus 8% [F];P< 0.0001), with added benefit if therapy was initiated prior to the blood culture. The targeted use of MB bottles is warranted for patients at risk for mycobacterial and fungal infections and for infection withB. pseudomallei, a common cause of septicemia in Thailand.