Rapid identification of cutaneous infections by nontubercular mycobacteria by polymerase chain reaction-restriction analysis length polymorphism of the hsp65 gene.

BACKGROUND: Nontubercular mycobacteria (NTM) may cause cutaneous infections which are difficult to interpret due to the variability of the clinical manifestations. This study involved eight patients (four men and four women) with primary cutaneous infections caused by NTM; the skin lesions included dermo-hypodermal abscesses, suppurative granulomas, and papulonodules localized on the legs, arms, hands, and face. The general condition of the patients was relatively good and they were not immunosuppressed.

METHODS: All samples were processed with standard methods and the isolates were identified by pattern restriction analysis after polymerase chain reaction (PCR-PCA) amplification of the heat shock protein of 65 kDa.

RESULTS: In this way, we were able to identify three Mycobacterium chelonae strains, two Mycobacterium marinum, two Mycobacterium fortuitum, and one Mycobacterium avium. The lesions disappeared in 3 or 4 weeks after treatment with two or more antimicrobials.

CONCLUSIONS: For a correct diagnosis of cutaneous infection by NTM, demonstrating the presence of mycobacteria is essential; routinely available techniques lack sensitivity and are extremely tedious; often mycobacteria are not seen after acid-fast stain. We used PCR-PCA to identify mycobacteria grown in liquid media; the time of identification of mycobacteria was shortened relative to conventional methods.