The study employed a cross-sectional approach which determined the antimicrobial usage (AMTJ) and characterization of antimicrobial resistance (AMR) in commensal Escherichia coli from healthy pigs collected in the municipality of Aritao, Bambang, Bagabag and Villaverde, Nueva Vizcaya. A survey questionnaire was administered to thirty-six (36) backyard farmers and the result revealed that 97 2% have no relevant training in antimicrobial usage and 88.9% rely on animal technician when it comes to antimicrobial access Majority of the respondents are not aware about the negative consequences (944%) and the concern of AMR (972%) Thirty-one (31) E. coli isolates were tested against 11 antimicrobials which are significant to human medicine through the use of the VITEK 2 System All isolates were found to be resistant to at least one antimicrobial Highest resistance was found in tetracycline (93.5%), trimethoprim sulfamethoxazole (83.9%) and ampicillin (774%) Resistance to chloramphenicol (38 7%) and gentamicin (35.5%) was also observed in the isolates. Lowest resistance was found in ciprofloxacin (97%) and aztreonam (3.2%). Multi-drug resistance was found to be high at 90.3% Eleven resistance patterns were found in the isolates The most common pattern is to three antimicrobials, ampicillin-tetracycline-trimethoprim sulfamethoxazole (29.0%) followed by resistance to five antimicrobials, ampicillin-chloramphenicol-gentamicin-tetracycline-trimethoprim sulfamethoxazole (22.6%). Risk factors identified on the occurrence of resistance includes obtaining prescription from veterinarians (p = 0.047) and farmers reliance on animal technicians (p = 0.002) usage of antimicrobials in treating all pigs (p = 0.027) and the practice of withdrawal period (p = 0.004) for gentamicin and chloramphenicol respectively. The findings of the study suggest that awareness campaigns and surveillance program on the usage of antimicrobials among backyard farmers in the province are necessary to reduce the prevalence and spread of antimicrobial resistance.

Thesis (Doctor of Veterinary Medicine)

includes appendices and bibliographical references.