RT Journal Article T1 Pasteurella multocida isolates associated with ovine pneumonia are toxigenic A1 Cid Vázquez, María Dolores A1 García Álvarez, Andrés A1 Domínguez Rodríguez, Lucas José A1 Fernández-Garayzábal Fernández, José Francisco A1 Vela Alonso, Ana Isabel AB The P. multocida toxin (PMT), a dermonecrotic protein encoded by the toxA gene, is the major virulence factor of capsular type D P. multocida strains causing progressive atrophic rhinitis (PAR) in pigs. A high frequency of P. multocida isolates harboring the toxA gene has been found among ovine pneumonic isolates, although the ability of these isolates to express PMT has never been examined. In this study we have investigated the ability of ovine toxA+ P. multocida isolates (n=57) to express a functional toxin by detection of PMT toxin antigen using an ELISA test and its cytopathic effect in a Vero cell assay. PMT antigen was expressed in the great majority (54/57; 94.7%) of toxA+ isolates. Moreover, the 100% toxA+ ovine isolates analyzed produced a cytopathic effect in Vero cells within 24–48 h post-inoculation, identical to that described for porcine toxigenic P. multocida isolates. These results show for the first time that, in addition to isolates associated with PAR, isolates of P. multocida associated with pneumonia in sheep are also toxigenic. In addition, we found a total agreement (Kappa=1; C.I. 0.75–1.25) between the detection of the toxA gene and the toxigenic capability of P. multocida isolates, indicating the PCR detection of toxA would be a suitable predictive marker of the toxigenic fitness of P. multocida. PB Elsevier SN 0378-1135 YR 2019 FD 2019 LK https://hdl.handle.net/20.500.14352/93250 UL https://hdl.handle.net/20.500.14352/93250 LA eng NO Cid Vázquez, M. D., García Álvarez, A., Domínguez Rodríguez, L. J. et al. «Pasteurella Multocida Isolates Associated with Ovine Pneumonia Are Toxigenic». Veterinary Microbiology, vol. 232, mayo de 2019, pp. 70-73. DOI.org (Crossref), https://doi.org/10.1016/j.vetmic.2019.04.006. NO Ministerio de Ciencia, Innovación y Universidades (España) DS Docta Complutense RD 7 abr 2025