Comparison of Mycobacterium avium isolates from Greek AIDS and human immunodeficiency virus-negative patients by pulsed-field gel electrophoresis

Objective To compare the chromosomal types of Mycobacterium avium strains i nfecting HIV-negative and AIDS patients in Greece. Methods In total, 41 Mycobacterium avium isolates, 23 from AIDS and 18 from HIV-negative patients, were compared by pulsed-field gel electrophoresis o f genomic DNA after XbaI digestion. The majority (87%) of AIDS isolates wer e from disseminated infection, while the majority (61%) of HIV-negative iso lates were from children with cervical lymphadenitis. Results Pulsed-field gel electrophoresis classified strains whose electroph oretic patterns were at least 85% similar into three clusters, A (four isol ates), B (12 isolates), and C (15), while 10 isolates remained outside of t hese clusters. There was no statistically significant correlation of any PF GE cluster with a specific patient group. Within each patient group, no sig nificant correlation of PFGE type with time, place of residence or, in the case of AIDS patients, hospital attended was observed. Conclusions Genotypic similarities between isolates responsible for dissemi nated infection in AIDS patients and lymphadenitis in HIV-negative children suggest that related strains, possibly from an environmental source, cause both types of infections.