Six-year report of mycobacteria recovered from automated culture system at Siriraj Hospital.

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.

Infection due to nontuberculous Mycobacterium other than MAC in AIDS patients at Siriraj hospital during 1998-2000: saprophyte vs pathogen.

HIV is a major health problem in Thailand. These patients are vulnerable to opportunistic infections, especially Mycobacterium tuberculosis and MAC infection. However, NTM was considered a rare disease in Thailand before the AIDS era. In this study, there were 38 HIV seropositive patients with NTM (other than MAC) identified from clinical specimens during the 3 year period 1998-2000 at Siriraj Hospital, which has a higher prevalence than the previous report. Among these patients, 29 cases were likely to have had definite infection from NTM, 5 cases possibly had NTM as a pathogen, and 4 cases had NTM as colonization. The most common site of infection was the lung (87%) and most common symptoms were cough (62.2%), fever (34.2%), weight loss (42.1%), and lymphadenopathy (5.3%). The outcome was poor because many NTM are not susceptible to standard medication for tuberculosis which is the empirical treatment for the majority of HIV seropositive patients with a clinical finding suspected of mycobacterial infection. The fatality rate was as high as 58.6 per cent. Awareness of NTM as a potential pathogen in HIV seropositive patientsand adjustment of medications even before the availability of culture results may improve the outcome of treatment of NTM infection in HIV seropositive patients.