GENETIC-CHARACTERIZATION OF MULTIDRUG-RESISTANT MYCOBACTERIUM-BOVIS STRAINS FROM A HOSPITAL OUTBREAK INVOLVING HUMAN IMMUNODEFICIENCY VIRUS-POSITIVE PATIENT

Nineteen multidrug-resistant (MDR) Mycobacterium complex strains isola ted in a nosocomial outbreak were characterized at the molecular level , The strains were microbiologically characterized as Mycobacterium bo vis. The mpt40 sequence was not present in chromosomal DNA from these strains, supporting the fact that they were M. bovis, All of the isola tes were resistant to isoniazid, rifampin, pyrazinamide, ethambutol, s treptomycin, para-aminosalicylic acid, clarithromycin, cycloserine, et hionamide, ofloxacin, capreomycin, and amikacin, By performing the sta ndardized IS6110 fingerprinting by restriction fragment length polymor phism (RFLP) analysis, we were able to differentiate two groups (group s A and B) containing two (16 isolates) and three (3 isolates) IS6110 copies, respectively, These strains were typed by spoligotyping, devel oped to distinguish M. bovis strains and also to distinguish them from M. tuberculosis strains (J. Kamerbeek et al., J. Clin, Microbiol, 35: 907-914, 1997), All the strains were confirmed to be M. bovis, In addi tion, spoligotyping showed a difference in only 1 of 43 spacers betwee n RFLP groups A and B, The rpo beta region of several strains represen tative of each identified group was cloned and sequenced, and identica l mutations (Ser-531 to Leu) responsible for the rifampin resistance p henotype were found, To our knowledge, this is the first characterizat ion at the molecular level of an MDR M. bovis strain responsible for a nosocomial outbreak.