Similar serovar and drug susceptibility profiles among AIDS-related Mycobacterium avium isolates from diverse geographic locations

Serotyping was performed on Mycobacterium avium isolates from 40 AIDS patients from 5 geographic sites: Boston (17 patients), New Hampshire (4 patients), Finland (12 patients), Trinidad (3 patients), and Kenya (4 patients). Serovars were similar from the five sites. Serovars 4 and 8 were the most common. In addition, minimal inhibitory concentrations to 8 antimicrobial agents were determined for 31 of these isolates and for 21 additional patient isolates from these sites. Minimal inhibitory concentration90 values for clarithromycin, azithromycin, clofazimine, amikacin, ethambutol, ciprofloxacin, sparfloxacin, and rifabutin were similar for isolates from the five geographic sites. Antimicrobial susceptibility patterns did not differ by serovar.

Rapid detection of Mycobacterium avium in stool samples from AIDS patients by immunomagnetic PCR

Direct PCR detection of bacteria in clinical samples is often hindered by the presence of compounds that inhibit the PCR. To improve and accelerate the diagnosis of Mycobacterium avium-M. intracellulare complex infections, an immunomagnetic PCR (IM-PCR) assay was developed. This IM-PCR procedure combines the separation of mycobacteria by antimycobacterial monoclonal antibody coupled to magnetic beads with an M. avium-M. intracellulare complex-specific PCR protocol based on 16S rRNA gene sequences. As few as 10 M. avium bacilli were detected in spiked human stool samples, a clinical specimen usually refractory to conventional PCR analysis, by the IM-PCR method. Moreover, M. avium organisms were detected in about 24 h in 18 of 22 culture-confirmed fecal samples from AIDS patients. This IM-PCR protocol should allow for the rapid and sensitive detection of M. avium isolates in clinical specimens.