Mycobacterium xenopi isolation from clinical specimens in the Florence area: review of 46 cases.

The occurrence of Mycobacterium xenopi (MX) isolates is not homogeneous in various geographic zones. In the Florence area, between 1975-1989, strains of MX from 64 different patients have been isolated. The review of bacteriological and clinical data of 46 of them, from whose sputum MX had been grown, allowed to diagnose for 26% the commensal nature of this finding, for 41% the concomitance with a tubercular infection and for the remaining 33% the pathogenicity of this microorganism. The increased occurrence of MX isolates, their high rate of pathogenicity and the remarkable homogeneity of their biochemical, cultural and antimicrobial sensitivity patterns seem to suggest the hypothesis of an endemic focus of this species in the Florence area.