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Detection of Mycobacterium avium subsp. paratuberculosis in fecal samples by culture in dairy farms in Panama

D Palacio(1,2) R Chérigo(1) D Candanedo(1) S Miranda(1) S Miranda(1) P Patel(1) A Pérez(1) E Cano(1) M Morán(1) D Sambrano(1) V Polanco(3) E Maldonado(4) G Chávez-Gris(4) F Acosta(1) R Whittington(5) A Goodridge(1)

1:Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta tecnología de Panamá (INDICASAT AIP), City of Knowledge, PANAMA; 2:Programa de Maestría en Microbiología Ambiental, Facultad de Ciencias Naturales y Exactas, Universidad de Panamá, PANAMA; 3:Facultad de Ciencias Agropecuarias, Universidad de Panamá. PANAMA; 4:Centro de Enseñanza, Investigación y Extensión en Producción Animal en Altiplano (CEIEPAA), Universidad Nacional Autónoma de México, MEXICO.; 5:Faculty of Veterinary Science, The University of Sydney, AUSTRALIA

Bovine paratuberculosis poses an economic challenge to dairy farms worldwide. Mycobacterium avium subsp. paratuberculosis (MAP) has been identified as an etiological agent. We aimed to evaluate the performance of liquid and solid culture media for isolating MAP from infected animals. We collected stool samples from 14 dairy farms in Chiriquí, Panama.  Samples were analyzed using acid-fast bacilli staining; liquid media M7H9C and A7H9J; solid media HEYM-PS, 7H11-M, and 7H9-OP; and confirmation with specific PCR targeting IS900R, F57, ISMAv-2, and Locus 255. We evaluated livestock management practices using a standardized questionnaire. Results show that liquid medium M7H9C yielded a higher bacterial load than A7H9J at sixth week of incubation (1.3 vs. 0.2 clumps/field; p < 0.05). Solid medium 7H9-OP yielded a higher bacterial growth than HEYM-PS and 7H11-M starting from the third week of incubation. When using the M7H9C liquid medium, we identified 5.5% (25/452) of animals with acid-fast bacilli (15.9 clumps/field average). Endpoint PCR confirmed MAP in 20% (5/25). Solid medium 7H9-OP identified 1.1% (5/452) animals with acid-fast bacilli (1 CFU each); PCR confirmed MAP in 60% (3/5). A 60% (3/5) of culture-positive farms employed animal purchase as a replacement method, and 40% (2/5) knew their health status. Additionally, 60% (3/5) of the farms housed calves with their mothers after calving. Our findings highlight M7H9C and 7H9-OP media's effectiveness in isolating MAP and the relationship of culture-positive farms with poor management practices. We recommend using culture to aid control measures in the dairy industry and tracking the spread of paratuberculosis.

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