Antimicrobial resistance profile in bacterial isolates from subclinical mastitic milk samples in dairy herds in Kenya

Abstract

This study was undertaken to investigate subclinical mastitis causing pathogens in dairy lactating cows and determine their antimicrobial susceptibility profile in rural and peri-urban areas of Thika, Mathioya and Kieni East Sub County. California Mastitis Test (CMT) was used to screen one hundred and sixteen lactating cows for subclinical mastitis. A total of 71 milk samples from cows that tested positive with CMT test were collected for bacterial isolation. The results show that Staphylococcus aureus was the most predominant bacterial isolates at 40.85%. This was followed by Coagulase negative Staphylococus (21.13%), Negative growth (15.49%), Streptococcus spp (9.86%), Streptococcus agalactiae (8.45%), Escherichia coli (2.82%). and Klebsiella spp (1.41%). Antimicrobial susceptibility testing results shows that bacteria isolates were susceptible to kanamycin, chloramphenicol and co-trimoxazole drugs but resistant to ampicillin and streptomycin. The study shows Staphylococcus aureus in the most predominant bacteria and most bacterial isolates are resistant to ampicillin and streptomycin. The study recommends regular surveillance programs to detect the risk of spread of antimicrobial resistance

Key words: Ampicillin, antibiotic resistance profiles, dairy cows, staphylococcus aureus.