RT Journal Article T1 Single-nucleotide polymorphism in two representative multidrug-resistant Mycobacterium bovis isolates collected from patients in a Spanish hospital harboring a human infection outbreak A1 Romero Martínez, Beatriz A1 Aranaz Martín, Alicia A1 Bezos Garrido, Javier A1 Álvarez Sánchez, Julio A1 Juan Ferré, Lucía De A1 Mateos García, Ana Isabel A1 Gómez Mampaso, Enrique A1 Domínguez Rodríguez, Lucas José AB Mycobacterium bovis is the etiological agent of tuberculosis in domestic and wild animals. Its involvement as a human pathogen has been highlighted again with the recent descriptions of transmission through dairy products (18), reactivation or primary infection in human immunodeficiency virus-infected patients (5), and association with meat industry workers, animal keepers, or hunters (3). Strains resistant to antituberculous drugs (M. bovis is naturally resistant to pyrazinamide) pose an additional risk (2). Several studies have demonstrated that mutations in target genes are associated with resistance to antituberculous drugs (4, 7, 10, 11, 16). However, most of them have been developed in Mycobacterium tuberculosis strains and limited data are available regarding M. bovis isolates.The aim of this study was to characterize by sequencing the main genes involved in antibiotic resistance in two multidrug-resistant (MDR) M. bovis isolates in a human outbreak detected in a hospital in Madrid that subsequently spread to several countries (5, 6, 15). The isolates were resistant to 11 drugs, but only their rpoB and katG genes have been analyzed so far (1, 14). We studied the first (93/R1) and last (95/R4) M. bovis isolates of this nosocomial outbreak, characterized by spoligotyping as SB0426 (hexacode 63-5F-5E-7F-FF-60 in the database at www.mbovis.org) (1, 13).Several genes involved in resistance to isoniazid (katG, ahpC, inhA, and the oxyR-ahpC intergenic region), rifampin (rpoB), streptomycin (rrs, rpsL), ethambutol (embB), and quinolones (gyrA) were studied. These genes, or fragments of genes, were amplified and sequenced as previously described (12).The sequence analysis revealed polymorphisms in five (ahpC, rpoB, rpsL, embB, and gyrA) out of nine analyzed genes (Table 1). Nucleotide substitutions in four genes cause a change in the encoded amino acid. Two additional synonymous mutations in ahpC and rpsL differentiated the first and last isolates from the outbreak. PB American Society for Microbiology SN 1098-660X YR 2008 FD 2008-02 LK https://hdl.handle.net/20.500.14352/51965 UL https://hdl.handle.net/20.500.14352/51965 LA eng NO Ministerio de Ciencia e Innovación (MICINN) DS Docta Complutense RD 7 jul 2025