Antimicrobial usage and presence of extended-spectrum β-lactamase-producing Enterobacteriaceae in animal-rearing households of selected rural and peri-urban communities.

This study examined socioeconomic and cultural factors relating to animal husbandry, antimicrobial usage and household hygiene in 320 animal-keeping households of 16 rural and peri-urban communities of Ogun State, Nigeria. The occurrence of extended-spectrum β-lactamase-producing Enterobacteriaceae in 457 samples from animal and environmental sources within the households was investigated. Chickens (41.6%), goats (35.3%), dogs (33.8%) and sheep (14.4%) were the most common household animals. Animals were reared mainly for income generation (73.9%) and for household consumption (18.3%). They were reared predominantly (60.2%-100%) under the extensive system with unrestricted access to human space, cooking utensils and foods. Households were assessed as having good (59.4%), fair (22.2%) and poor (18.4%) hygiene. The rate of household non-prescriptional antimicrobial usage was 69.4% in humans and 60.6% in animals. Overall, ESBL-producing Enterobacteriaceae were detected in 53 (11.6%) of 457 samples. The ESBL-producing isolates were identified as Escherichia coli (n = 49) and Klebsiella pneumoniae (n = 4). They harboured the ESBL gene variants blaCTX-M-15 (n = 49), blaCTX-M-14 (n = 2), blaCTX-M-27 (n = 1) or blaCTX-M-55 (n = 1). Forty-eight ESBL-producing E. coli were assigned into phylogenetic groups A (n = 17), B1 (n = 14), D (n = 13) and F (n = 4). All ESBL-producing isolates demonstrated multidrug resistance to antimicrobial agents belonging to at least three different classes of antimicrobials. Poor regulation of antimicrobial marketing and inadequate access to veterinary care contributed to non-prescriptional use of antimicrobials in humans and animals. Free-range household animals harboured ESBL-producing bacteria and may facilitate the dispersal of the organisms within the community.