Determination of Antibiotic Resistance Pattern in Klebsiella pneumoniae Strains Isolated from Bovine Mastitis in Shahrekord, Iran

Bovine mastitis is one of the most common diseases in dairy cattle that is caused by various infectious agents, such as Klebsiella pneumoniae. The aim of this study was to detect Klebsiella pneumoniae in bovine clinical and subclinical mastitis and investigate the antibiotic resistance pattern of this bacterium. A total of 130 milk samples were collected from diary cattle with mastitis in the dairy farms of Shahrekord, Iran. After microbial culture and molecular confirmation of Klebsiella pneumoniae strains, the presence of the most common genes encoding antibiotic resistance in these isolates was determined by polymerase chain reaction. In addition the phenotypic pattern of these isolates were investigated by the simple disk diffusion method. For statistical analysis, Chi-square and Fisher’s exact tests were run in SPSS software (version 20) at 95% confidence level. Out of the 130 samples tested, 20 (15.38%) specimens were infected with Klebsiella pneumoniae. In these isolates, most of the genes encoding antibiotic resistance were detected. In this regard, the sulI and aadA1 genes with the frequencies of 70% and 65% had the highest prevalence, and the cat1 and cm1A genes with a frequency of 25% were identified as the rarest antibiotic resistance genes detected in these isolates. All isolates were resistant to penicillin and tetracycline. Multiple antibiotic resistance in Klebsiella pneumoniae strains indicates the unnecessary use of antibiotics in the treatment of infectious diseases and the need for antibiograms to select the most effective antibiotic in the treatment of bovine mastitis.