Six-year Report of Mycobacteria Recovered from Automated culture System at Siriraj Hospital

Abstract

An increased incidence of tuberculosis and other mycobacterial infections among immunocompromised patients has created a serious health crisis, especially in resource-poor countries. In addition, disseminated disease occurs more frequently in these patients. Rapid isolation and accurate identification of causative agents are necessary for selecting an appropriate treatment regimen. Since an isolation of Mycobacterium tuberculosis and slowly growing mycobacteria require 3-4 weeks for conventional culture, the automated system can reduce the detection time to 7-10 days. The present study demonstrated the mycobacteria recovered from hemocultures and other sterile body fluids, using the BACTEC 9000 system. Overall, 5,490 samples during the period 1998-2003 were submitted for hemocuture and the isolated mycobacteria were identified by using molecular techniques, like multiplex PCR and PCR-REA. The results demonstrated that~18-28% of hemocultures were positive for mycobacteria. Of these, M. tuberculosis appeared to be the most common species among mycobacteria isolates whereas the M. avium complex was found to be the second most common. The combined use of an automated culture system and molecular techniques as shown in this study is a useful procedure for rapid isolation and identification of mycobacteria that can reduce the time from 6-8 weeks to 2-3 weeks.