Antibiotic susceptibility patterns of pathogenic bacteria recovered from unprocessed bovine milk produced in Ndivisi Ward, Bungoma County

Author: Wanyama Milton, Mario Kollenberg, Siamba N Donald, Nyongesa Peter

Category: Research Article

Abstract:

This study was conducted to determine the antibiotic susceptibility patterns of pathogenic bacteria recovered from unprocessed bovine milk. Bacterial communities were isolated from the milk samples and then subjected to antibiotic susceptibility testing. Pure colonies were used to avoid contamination. The study was carried out in Ndivisi ward, Bungoma County, Kenya, between October 2016 to January 2017. The level of antibiotic resistance among the isolates was tested to amoxicillin, chloramphenicol, kanamycin, gentamicin, cephalexin, and tetracycline. The responses of the isolates to antibiotics were determined by measuring the diameter of the zone of inhibition around the antibiotic disk. These measurements were subsequently converted into a qualitative scale using the standard charts. Data on the bacteriological quality of milk were summarized using means. Means were determined since each bacterium species had several isolates. The percentages of bacteria resistant to antibiotics included amoxicillin (63%), kanamycin (19%), cephalexin (41%), and tetracycline (19%). Intermediate ones were kanamycin (33%) and cephalexin (22%). Susceptible ones were amoxicillin (37%), gentamicin (100%), kanamycin (48%), cephalexin (37%), chloramphenicol (100%) and tetracycline (81%). Generally, 62% of the bacteria were resistant, 33% were intermediate while 5% were susceptible. B. subtilis, P. aeruginosa, and C. freundii were multidrug-resistant bacteria. Cephalexin and kanamycin were intermediate to E. coli and B. subtilis. K. pnemoniae and S. aureus were susceptible to amoxicillin, chloramphenicol, kanamycin, gentamicin, cephalexin, and tetracycline. Most bacterial isolates were resistant to the six commonly used antibiotics. The concentration of intermediates should be increased to be effective again while those which were resistant should be replaced.

Keywords: antibiotic susceptibility patterns, pathogenic bacteria