To study the sensitivity of field strains of Str. agalactiae and Str. uberis — causative agents of cow mastitis to a drug based on marbofloxacin

Abstract

An increase in the number of resistant strains of mastitis pathogens Str. agalactiae and Str. uberis is one of the causes of massive subclinical and clinical mastitis in cows. The aim of the study was to study the sensitivity of field strains of Str. Agalactiae and Str. uberis to the drug based on marbofloxacin «Marboflocin 10%» (LLC «AleksAnn»), as well as to a number of the most commonly used antibacterial drugs (ABP). Sensitivity to marbofloxacin was determined by the method of serial dilutions, to other antibacterial drugs — by the disco-diffusion method. 15 samples of breast secretions from cows with a clinical form of mastitis were examined, from which 15 cultures of streptococci were isolated, including Str. agalactiae and Str. uberis — in 53.3% of the samples. All isolated cultures of Str. Agalactiae and Str. uberis were susceptible to marbofloxacin. The mean value of the minimum inhibitory concentration (MIC) of marbofloxacin for cultures of Str. uberis is 0.50 µg/ml, and for Str. agalactiae — 0.44 ± 0.13 µg/ml. To other antibacterial drugs, the studied cultures of Str. uberis and Str. agalactiae showed different sensitivity, resistance to amoxicillin was revealed, incl. with clavulanic acid, tylosin