Mycoplasma dispar prevalence in the upper respiratory tract of cattle and the antimicrobial susceptibility of the isolates

Abstract

The aim of this study was to make a survey of the presence of Mycoplasma dispar on a cattle breeding farm and to determine antimicrobial susceptibility of the isolates.The study was carried out at a farm in Lithuania. Nasal swabs for bacteriological investigation were collected from ninety dairy, beef and mixed type of cattle from 90 to 300 days of age. Mycoplasma cultivation procedures were carried out using Friis selective media. To confirm the presence of Mollicutes class the polymerase chain reaction (PCR) was used. Isolates were identified according to biochemical and antigenic characteristics.The minimum inhibitory concentration of twenty field isolates of Mycoplasma dispar to tulathromycin, tylosin, lincomycin, enrofloxacin, florfenicol, and oxytetracycline was determined by using a micro-broth dilution method.Mycoplasma dispar was detected in the nasal cavity of 15 out of 84 clinically healthy animals (17.9 %), and in 5 out of 6 animals with respiratory disorders (83.3 %). The isolates were most susceptible to tulathromycin, lincomycin, enrofloxacin and florfenicol. Three (15 %) isolates were resistant to oxytetracycline.The susceptibility to oxytetracycline significantly differed between Mycoplasma dispar isolates compared to the susceptibility of tulathromycin (P < 0.001), lincomycin (P < 0.001) tylosin (P < 0.001), enrofloxacin (P < 0.001), and florfenicol (P < 0.001).