Houseflies (Musca domestica L.) are known carriers of infectious agents which may include multidrug-resistant (MDR) pathogenic bacteria. Thus the prevalence and antibiotic resistance profiles of housefly-borne enteric bacteria in 16 Nigerian urban-based abattoirs and their dispersal in built environment surrounding the abattoirs were investigated. The insect-baiting technique was used to capture 1600 houseflies in the abattoirs and surrounding residential/commercial buildings’ outdoor environments. Enteric bacteria were isolated from the flies using selective and differential media, and they were identified by cultural and biochemical characteristics. Antibiotics resistance of these bacteria was ascertained by agar diffusion technique using 15 antibiotics. The identified isolates were Escherichia coli, Salmonella enterica, Shigella dysentariae and Klebsiella pneumonia with prevalence variations of 4.3-7.3% and 4.5-7.4% in abattoirs and buildings’ outdoor environment, respectively. The enteric bacteria populations from abattoirs to buildings did not correlate with distance (r=0.03-0.10; P>0.05); and no significant inter-bacterial correlation in dispersals was found except between S. enterica and S. dysentariae (r=0.65; P=0.006). All the isolates were susceptible to ceftriaxone and gentamycin, while varied resistance and susceptibility was observed with respect to other antibiotics. The isolates were mostly MDR with multiple antibiotics resistant index of 0.50-0.78 without significant difference between isolates from the abattoir and buildings’ outdoor houseflies. Compared to building outdoors, MDR isolates from abattoir houseflies were significantly more in number (P=0.000-0.015) in over 65% of the abattoir locations. These findings can be an impetus for the intervention of public health agencies in abattoir operations to control the dispersal of MDR bacteria in built environment.
