RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSIS OF CLINICAL ISOLATES OF MYCOBACTERIUM-HAEMOPHILUM

Mycobacterium haemophilum is an emerging opportunistic pathogen, and s ince 1989, infections caused by this organism have been identified mor e frequently in the New York City area than in any other region of the United States. A DNA fingerprinting method, based on restriction frag ment length polymorphisms (RFLPs) was developed. A genomic library of M. haemophilium isolate IA was constructed; screening the library yiel ded a recombinant strain that incorporated a genetic element present i n multiple copies in the M. haemophilum genome. This clone was used to produce a probe for RFLP analyses of PvuII digests of genomic DNA. We used this probe to determine the RFLP patterns of 43 clinical isolate s of M. haemophilum from 28 patients. A total of six distinct patterns were observed. Two patterns, designated types 1 and 2, accounted far 91% of the infections in patients from the New York City area. Two iso lates from Arizona had identical patterns but were distinct from those of New York isolates, and an isolate from Israel, the type strain, ha d another distinct pattern (type 6). The type 6 pattern was also seen in a recent isolate from Norway. All of the type 1 isolates and 60% of the type 2 isolates were recovered from patients with AIDS in the New York City area. This molecular subtyping method should provide a usef ul tool for epidemiological studies and may help identify the associat ed risk factors, vehicles, and possible reservoirs of this newly emerg ing pathogen.