Detection of sensitive and mutant ruminal bacteria isolates from sheep, cattle, and bufalo using 14 therapeutic antibiotics

Abstract

In the present study, sensitive and mutant colonies of some ruminal bacterial species isolated from sheep, cattle, and bufalowere detected. We counted and considered mutant colonies the bacterial colonies grown in the clear inhibition zone in the Kirby Bauerdisk difusion susceptibility test. Detected mutant colonies were higher in bufalo than in cattle and sheep. Duricef and metronidazolecaused no mutations in any species. Te others formed mutant colonies, where roxithromycin = polymyxin = chloramphenicol =gentamicin streptomycin = piperacillin > erythromycin >vancomycin = cefoperazone = cefotaxime > roxithromycin > polymyxin > chloramphenicol). Te number of sensitive isolates of thediferent ruminant species for all the antibiotics was highest in bufalo, followed by cattle and then sheep (P < 0.05). We could concludethat subtherapeutic antibiotic use in ruminant feeding may lead to the formation of antibiotic-resistant mutant colonies, making theirsubtherapeutic efect nonexistent.