Prevalence and Antimicrobial Resistance of Campylobacter spp. in the Raw Milk of Backyard-Raised Carabaos (Bubalus bubalis) in the Philippines

Eleanor Austria, Marinette M. Carpio, Kian J. Elman, Jhasmine Falogme, Jarale Cabagbag, Christian Munoz, Nina Amores, Hannah Soriano, Gabriel Tubalinal, Fredelon Sison and Claro Mingala

Background and Objective: The World Health Organization listed Campylobacter spp. as one of the most common food-borne bacterial pathogens worldwide. In the Philippines, Campylobacter contamination in chicken are well established but there is a research gap on the presence and antimicrobial resistance of Campylobacter spp., in raw carabaos’ milk. This study aims to determine the prevalence of Campylobacter spp., in the raw milk and its resistance to common antimicrobial agents. Materials and Methods: This study utilized the combination of conventional culture method and a commercial milk bacterial DNA isolation kit to detect the presence of Campylobacter coli and Campylobacter jejuni in raw milk. In both methods, Campylobacters were genotyped with primers that encode for lipid A; while antibiotic resistance was determined using primers for tetracycline (tetO) and ampicillin (blaOXA-61) resistance genes. Results: Out of 107 raw milk samples, C. coli was detected in 0.94% of the samples using conventional culture method and on 6.54% (95% CI, 3.2-12.9%) using the commercial kit. No C. jejuni were detected using both methods. No genes that encode for tetracycline and ampicillin resistance were detected but phenotypic testing showed intermediate resistance to ampicillin. During the analysis, several Campylobacter-like colonies grew on the selective media but 16S gene sequencing revealed the colonies to be Acinetobacter baumannii (59%) and Pseudomonas aeruginosa (23%). Conclusion: Results confirmed the presence of C. coli in raw carabaos milk which possess resistance against ampicillin, suggesting that a review of the milk handling protocol in backyard farms is necessary. Further, the difficulty encountered in the isolation of Campylobacters can be a source of bias and must be considered in future surveillance programs for this food-borne pathogen.

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