Tipificación molecular de mannheimia haemolytica y pasteurella multocida asociadas a la pasteurelosis neumónica ovina

Resumo

Pneumonic pasteurellosis is one of the diseases that has the greatest economic impact on sheep production worldwide and one of the most important diseases in the neonates. M. haemolytica and P. multocida are the main bacterial agents associated with these processes in small ruminants. The main objective of this study was the genetic characterization of the isolates of M. haemolytica and P. multocida associated with the pneumonic lesions characteristic of the pneumonic pasteurellosis in sheep with the purpose of contributing to the improvement of the diagnosis and vaccine design for the prevention of these conditions in sheep. For this, molecular typing techniques such as "multilocus sequence typing" (MLST), pulsed field electrophoresis (PFGE) and virulence profile typing ("virulotyping") were used. In the 121 isolates of M. haemolytica analyzed a total of 12 STs were detected by MLST. The most frequent STs were ST16 (50/121, 41.3%), ST 28 (29/121, 24.0%) and ST8 (19/121, 15.7%). The differences in frequencies and distribution of ST between lung isolates with and without pneumonic lesions were not statistically significant (P> 0.05). These three TS represent 27% of the sheep isolates, ST16 and ST8 represent almost a third of the goat isolates included in the MLST database of M. haemolytica, which indicates a wide distribution of these genotypes in small ruminants. Furthermore, this, together with the fact that these STs have not been identified in bovine isolates, suggests the adaptation of certain genetic lineages of M. haemolytica to small ruminants...