Abstract

VILLEGAS VAZQUEZ, Ana Lilia et al. Characterization of capsular types of Pasteurella multocida isolated from clinically healthy beef cattle pharyngeal exudate in the state of Querétaro. Vet. Méx [online]. 2014, vol.45, n.spe, pp.19-28. ISSN 0301-5092.

The objective of the present study was to identify and characterize capsular types of P. multocida isolated from beef cattle pharyngeal exudate in the state of Querétaro. Two hundred and twenty seven pharyngeal exudate swab samples from clinically healthy animals in a slaughterhouse in the municipality of Ezequiel Montes, Querétaro were obtained. Samples were seeded in blood agar and incubated at 37°C for 24 h under aerobiosis. Strains were identified through morphological characteristics, conventional biochemical tests and commercial API 20NE Micro-System. Capsular typing of groups A and D was performed by a multiplex PCR for amplification of genes hyaD-hyaC and dcbF, respectively. According to the values established by API WEB software, it was possible to identify 14.09% (32/227) of P. multocida strains, which showed an identification percentage of 96% and a typicality of 1 to P. multocida. By multiplex PCR, the amplification of genes hyaD-hyaC, correspondent to capsular group A in 100% (32/32) of the strains previously identified as P. multocida, was achieved. There are no similar data in Mexico on the identification and characterization of P. multocida in beef cattle. With the results obtained it is confirmed that, in a similar way with other countries of Europe and America, capsular type A of P. multocida is predominant in Mexico.

Keywords : Pasteurella multocida; capsular types; biochemical characterization; molecular characterization; pharyngeal exudate; cattle; PCR.