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ISPEC 3. Uluslararası Tarım, Hayvancılık ve Kırsal Kalkınma Kongresi, Van, Turkey, 20 - 22 December 2019, pp.140-141
In this study, it was investigated that minimal inhibitory concentration of various antimicrobial agents and the presence of the genes associated with antimicrobial resistance and toxin synthesis in Mannheimia (M.) haemolytica and Pasteurella (P.) multocida strains isolated from mastitis and pneumonia cases in sheep. In the research, 7 M. haemolytica and 3 P. multocida capsule type D isolates obtained from mastitis cases and 3 P. multocida capsule type A strains obtained from pneumonia cases were used.
All M. haemolytica isolates examined by PCR were found to be positive for lkt-1 gene. Also, tox A gene was detected in 2 (66.6%) and 3 (100%) of P. multocida capsule type A and D isolates, respectively.
MIC values of penicillin, ampicillin, cefoxitin, sulfamethoxazole+trimethoprime, tetracycline, enrofloxacin, erythromycin, tilmicosin, streptomycin, and gentamycin for M. haemolytica isolates examined by E-test were detected as 0.25-0.50, 0.25-0.50, 0.19-0.50, 0.016-0.047.0 -1, 0.008-0.50, 0.50-1.5, 0.064-8, 8-24 and 0.75-1.5 µg/ml, respectively. Also, MIC values of these antimicrobial agents for P. multocida isolates were 0.19-0.50, 0.38-0.50, 0.38-0.50, 0.032 - >32, 0.032-1, 0.002-0.012, 0.50-1.5, 4 - >32, 3-8 and 0.25-1.5 µg/ml, respectively. Accordingly, 2 (28.5%) of M. haemolytica isolates and 3 (50%) of P. multocida isolates were found to be resistant to tilmicosin whereas only one of P. multocida isolate was resistant to sulfamethoxazole + trimethoprime. Genes associated with antimicrobial resistance could not be detected in the resistant isolates.
The results of this study indicated that toxigenic strains of M. haemolytica, P. multocida capsule type A and capsule type D might play an important role in mastitis and pneumonia cases in sheep. In addition, it was concluded that antimicrobial resistance in sheep isolates was not very high, but due to the development of resistance, the use of tilmicosin in treatment should be considered.