Potential of cattle rumen waste as a source of antibioticresistant bacteria dissemination in the environment

The identification of possible sources of antibiotic-resistance dissemination in the environment is one of the ways to tackle the menace of globally challenging antibiotic resistance. This study reported the antibiotic-resistance pattern of bacteria isolated from fresh rumen waste of cattle culled at four privately-owned abattoirs in Osogbo, the Southwestern part of Nigeria. Bacteria were isolated and identified using standard cultural techniques and biochemical characterization tests. The bacterial isolates were tested against twelve antibiotics using the Kirby-Bauer disc diffusion method. The totalheterotrophic bacterial count obtained for the four different abattoirs ranged between 2.95 x 109 ± 1.14 CFU g-1 and 1.01 x 1011 ± 1.02 CFU g-1. Bacterial isolates presumptively identified include Brevundimonas diminuta, Chryseomonas luteola, Citrobacter diversus, Enterobacter intermedius, Escherichia coli, Klebsiella oxytoca, Providencia rettgeri, Pseudomonas sp., Shigella dysenteriae, Stenotrophomonas maltophilia, and Tatumella ptyseos. Thirty-seven (92.5%), eighteen (45%), fourteen (35%), and ten (25%) out of the total 40 bacteria isolated were resistant to augmentin, tetracycline, cotrimoxazole, and gentamicin respectively. The percentage resistance to nalidixic acid (5.9%) and ofloxacin (2.9%) was low among the Gram-negative bacteria, while the percentage resistance to nitrofurantoin was 23.5%. All the Gram-positive bacteria were sensitive to streptomycin while 66.7% were resistant to erythromycin. Multidrug-resistant bacteria isolated were 23 (57.5%). The results of the study showed that rumen waste generated from cattle culled for human consumption at abattoirs in Osogbo metropolis, Nigeria can be a possible source of spreading antibiotic-resistant bacteria in the environment.