MOLECULAR TYPING OF MOROCCAN MYCOBACTERIU M-TUBERCULOSIS ISOLATES

The insertion sequence IS 6110 was used to differentiate clinical Moro ccan isolates of Mycobacterium tuberculosis by using two non radioacti ve probes. Among 16 strains isolated from patients clinically related, 10 had similar IS 6110 restriction fragment length polymorphism (RFLP ) patterns, confirming that they were derived from a common source. Tw o strains were isolated from the same patient (sputum, lymph node) sho wed identical profiles hybridized with IS 6110 element Four sequential strains isolated from the same patients before treatment and after on e year had identical IS 6110 RFLP patterns suggesting relapse and not reinfection. Twenty-one strains with identical drug susceptibility sho wed different IS 6110 RFLP profiles confirming no correlation between antibiotic resistance profiles and IS 6110 RFLP patterns. Since, RFLP analysis by using IS 6110 element is a useful tool for the epidemiolog ical survey of tuberculosis.