Mycobacterium tuberculosis subsp. caprae subsp. nov.: a taxonomic study of a new member of the Mycobacterium tuberculosis complex isolated from goats in Spain

1 Departamento de Patología Animal I (Sanidad Animal), Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain 2 Servicio de Microbiología, Hospital Ramón y Cajal, 28034 Madrid, Spain 3 Australian Reference Laboratory for Bovine Tuberculosis, Agriculture Western Australia, South Perth 6151, Australia 4 Centro Nacional de Investigación Clínica y M. P., Hospital Carlos III, 28029 Madrid, Spain Author for correspondence: Lucas Domínguez. Tel: +34 91 3943721. Fax: +34 91 3943908. e-mail: alaranaz{at}eucmax.sim.ucm.es ABSTRACT Isolates from the Mycobacterium tuberculosis complex cultured from caprine pathological tissue samples were biochemically and genetically characterized. The isolates were negative for nitrate reduction and niacin accumulation, they weakly hydrolysed Tween 80, were sensitive to pyrazinamide (50 µg ml –1 ) and were resistant to 1 and 2 µg tiophene-2-carboxylic acid hydrazide ml –1 but not to 5 or 10 µg tiophene-2-carboxylic acid hydrazide ml –1 . Sequencing of the pncA gene revealed a polymorphism characteristic of M. tuberculosis , whereas oxyR, katG and gyrA sequences were characteristic of Mycobacterium bovis. The fingerprinting patterns obtained with IS6110, direct repeats and polymorphic G+C-rich sequence-associated RFLP and direct variable repeat-spacer oligonucelotide typing (spoligotyping) segregated these isolates from the other members of the complex. The results of this testing, together with the repeated association of this micro-organism with goats, suggest that a new member of this taxonomic complex not matching any of the classical species had been identified. This unusual mycobacterium may play a role in the epidemiology of animal and human tuberculosis in Spain. The name Mycobacterium tuberculosis subsp. caprae subsp. nov. is proposed for these isolates. The type strain of Mycobacterium tuberculosis subsp. caprae subsp. nov. is gM-1 T (= CIP 105776 T ). Key Words: Mycobacterium tuberculosis subsp • caprae subsp. nov. • Mycobacterium tuberculosis complex • tuberculosis • goats The EMBL accession number for the 16S rRNA gene sequence of strain gM-1 T is AJ131120 .