Ribotipificación de aislamientos de Mannheimia haemolytica serotipo 1 obtenidos de exudado nasal de bovinos productores de leche en México

Abstract

RESUMENSe realizó la caracterización genética de 106 aislamientos de M annheim ia haem olytica serotipo 1 (S1) obtenidos de exudado nasal de bovinos clínicamente sanos (BCS) (n= 80) y enfermos (BCE) (n= 26) de neumonía de dos granjas lecheras del centro y norte de México, mediante la técnica de ribotipificación. De los cuales se extrajo el DNA para realizar el proceso de digestión con la endonucleasa de restricción HindIII y la posterior ribotipificación, que se realizó utilizando una sonda que contenía el operon rrnB ABSTRACTOne hundred and six (106) isolates of M annheim ia haem olytica serotype 1 (S1) obtained from nasal exudates of clinically healthy cows (n= 80) and cows diagnosed with pneumonia (n= 26) from two dairy farms located in central and northern Mexico were genetic characterized using a ribotyping technique. DNA was digested by HindIII and a probe containing the rrnB rRNA operon was used for ribotyping. Two ribotyping patterns were identified: Rt1 and Rt2, both with bands of approximate size between 0.78 and 19.70 kb. Rt1 had 11 hybridization bands and Rt2, 13. Ninety-six (96) percent of the isolates (102/106) were grouped into a cluster within Rt1; the similarity value between Rt1, Rt2 and the reference strain was 70 %. There were no differences between Rt isolates from healthy cows or cows with pneumonia. These results show that the majority of the strains were grouped within the Rt1 forming a single cluster, regardless of their geographic origin or the cows' health status.