Molecular Analysis of Mycobacterium avium Isolates by Using Pulsed-Field Gel Electrophoresis and PCR

Abstract

Genetic relationships among 46 isolates of Mycobacterium avium recovered from 37 patients in a 2,500-bed hospital from 1993 to 1998 were assessed by pulsed-field gel electrophoresis (PFGE) and PCR amplification of genomic sequences located between the repetitive elements IS1245 and IS1311. Each technique enabled the identification of 27 to 32 different patterns among the 46 isolates, confirming that the genetic heterogeneity ofM. avium strains is high in a given community. Furthermore, this retrospective analysis of sporadic isolates allowed us (i) to suggest the existence of two remanent strains in our region, (ii) to raise the question of the possibility of nosocomial acquisition ofM. avium strains, and (iii) to document laboratory contamination. The methods applied in the present study were found to be useful for the typing of M. avium isolates. In general, both methods yielded similar results for both related and unrelated isolates. However, the isolates in five of the six PCR clusters were distributed among two to three PFGE patterns, suggesting that this PCR-based method may have limitations for the analysis of strains with low insertion sequence copy numbers or for resolution of extended epidemiologic relationships.

Differential Genotyping of Mycobacterium avium Complex and Its Implications in Clinical and Environmental Epidemiology

“…PFGE, IS1245-PCR, and IS1311-PCR analyses revealed that M. avium isolates from a hospital exhibited varied genotypes. The IS element-PCR analysis detected 2-3 patterns, whereas PFGE analysis detected 5-6 groups, indicating the limitations of IS element analysis [62]. M. intracellulare isolated 21 from patients suffering from bronchiectasis were analyzed by VNTR and PFGE analysis.…”