TDK conference 2020

Although the sheep and goat meat consumption in Hungary is quite low, live lamb and lamb meat are important export articles. Pasteurellosis, caused by Mannheimia haemolytica and Bibersteinia trehalosi is a common disease in sheep and goat stocks, and causes high economic damage especially for lambs and kids. The impact can be moderated by antibiotic treatment, in the early stage of the disease.

The aim of our study was, to examine the antibiotic susceptibility of M. haemolytica and B. trehalosi strains, isolated from Hungarian small ruminant flocks using two methods. We created strain collection from M. haemolytica and B. trehalosi isolates, that originated from cases of diagnostic institutes and slaughterhouses. Only strains from pathological lesions, and strains belonging to different serotypes from each place of origin were involved in the study. A total of 68 M. haemolytica and 12 B. trehalosi strains isolated from 45 Hungarian settlements were examined.

Antibiotic susceptibility tests were performed by 12 antibiotics (amoxicillin, amoxicillin-clavulanic acid, ceftiofur, enrofloxacin, florfenicol, gentamicin, lincomycin-spectinomycin, oxytetracycline, sulfamethoxazole-trimethoprim, tiamulin, tilmicosin, tulathromycin) both with disc diffusion and broth dilution methods.

The majority of the Hungarian M. haemolytica and B. trehalosi strains were susceptible to amoxicillin, amoxicillin - clavulanic acid, ceftiofur, enrofloxacin, florfenicol, oxytetracycline, sulfamethoxazole-trimethoprim, tilmicosin and tiamulin antibiotics using the broth dilution method. Moderate susceptibility or resistance were detected against gentamicin and lincomycin-spectinomycin, while the strains were mainly resistant against tulathromycin Using the disc diffusion method results, the majority of the strains were susceptible to oxytetracycline, florfenicol, enrofloxacin, ceftiofur, tulathromycin antibiotics. According to our results, in vitro the most effective antibiotics against pasteurellosis were amoxicillin, ceftiofur, florfenicol, enrofloxacin, tilmicosin and tiamulin, but oxytetracycline and sulfamethoxazole-trimethoprim were also acceptable. The results of the two methods correlated mostly well.

The susceptibility of the B. trehalosi strains usually fell in a lower range than of the M. haemolytica strains. There was no significant difference in the susceptibility within the serotypes of each species.