ANTIBIOTIC SUSCEPTIBILITY PATTERNS OF PATHOGENIC BACTERIA RECOVERED FROM UNPROCESSED BOVINE MILK PRODUCED IN NDIVISI WARD, BUNGOMA COUNTY

Abstract

Milk is an essential and nutritive product that fulfills the increasing demand for food in the rising population in the former western province of Kenya. Milk can be easily contaminated by bacteria posing a health risk to human consumers. Similarly, antibiotic resistance is emerging as a great concern as it makes the control of diseases difficult by reducing the effectiveness of the available drugs. The antibiotics used for treatment of animals has an effect on the levels of bacterial resilient in humans, yet the exact health impacts are poorly understood. A total of 486 samples were collected from individual animal and bulk milk and outlets market places. Bacterial communities were isolated from the samples and then subjected to antibiotic susceptibility testing. The bacteriological status of milk was assessed by total plate count, isolation and identification of pathogenic bacteria and testing for antibiotic susceptibility patterns. The level resistance to antibiotic among the isolates was tested to amoxicillin, chloramphenicol, kanamycin, gentamicin, cephalexin, and tetracycline. The responses of the isolates to antibiotics were established by measuring the diameter of the zone of inhibition around the antibiotic disk. These measurements were subsequently converted into a qualitative scale using standard charts. Data on the bacteriological quality of milk were summarized using means and standard deviation. The difference in bacterial counts between sub-locations, sources of milk and the difference in response to antibiotics and levels of antibiotics between and within groups in the study was assessed using analysis of variance (ANOVA). Statistical significance was set at p<0.05 using a computer package, SPSS software version 20.0. Out of 486 samples collected only 235 samples (48.4%) were contaminated. Staphylococcus aureus was (28.1%) in abundance, pathogenic Escherichia coli (21.7%), Pseudomonas aeruginosa (19.1%), B subtilis (11.5%), Citrobacter freundii (10.2%) and Klebsiella pnemoniae (9.4%). Percentages of bacteria resistant to antibiotics are amoxicillin (63%), kanamycin (19%), cephalexin (41%) and tetracycline (19%). Those that are intermediate: kanamycin (33%) and cephalexin (22%). Susceptible ones: amoxicillin (37%), gentamicin (100%), kanamycin (48%), cephalexin (37%), chloramphenicol (100%) and tetracycline (81%). Generally, 62% of the bacteria are resistant, 33% are intermediate while 5% are susceptible. Lutacho sub-location had the highest bacterial counts, followed by Misemwa, Wabukhonyi, Marinda, Makuselwa, and Lowest in Sitabicha. B. subtilis, P. aeruginosa and C. freundii are multidrug-resistant bacteria. Cephalexin and kanamycin are intermediate; their concentrations need to be increased to be used again against E. coli and B. subtilis. K. pnemoniae and S. aureus are susceptible amoxicillin, chloramphenicol, kanamycin, gentamicin, cephalexin, and tetracycline. The information generated from this study has shown antibiotic susceptibility patterns among pathogenic bacteria in unprocessed bovine milk. The information can be used to improve antimicrobial surveillance systems like Atlas which creates awareness. This information provides evidence of antibiotic resistance two of which are key objectives of the FAO action plan on AMR, similarly, it’s of great importance to veterinary officers, public health officers, dairy technologists, dairy farmers, and consumers.