Extended-spectrum ß-lactamase-producing Escherichia coli among humans, chickens and poultry environments in Abuja, Nigeria

Abstract

Background: Globally, chicken is known to be a reservoir for the spread of antimicrobial resistance genes to humans. In Nigeria, antimicrobial drugs are readily accessible for use in poultry production, either for preventive or therapeutic purposes. Extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) are transmissible to humans because of their zoonotic potentials. People working very closely with chickens either on farms or markets are at greater risk. The aim of this study was to investigate the prevalence and zoonotic transmission of ESBL-EC among poultry-workers, chickens, and poultry environments in Abuja, Nigeria.

Methods: We conducted a cross-sectional study among workers, chickens and poultry environment in selected farms/chicken markets in Abuja. Stool, faecal, and environmental samples were collected from apparently healthy workers, chickens, and farm/market environments from December 2018 to April 2019. Data were collected electronically using an open data kit (ODK) installed on a Smartphone. Antimicrobial resistance was determined using broth micro-dilution methods against a panel of 14 antimicrobial agents. We carried out the phenotypic and genotypic characterization of the isolates. Data were analyzed by computing frequencies, proportions and spearman's correlation (ρ).

Results: Of 429 samples, 26.8% (n = 115) were positive for Escherichia coli (E. coli). Of the 115 E. coli isolates, 32.2% (n = 37) were confirmed ESBL producers by phenotypic characterization. Prevalence of ESBL-EC was highest among both poultry-workers (37.8%; n = 14) and chickens (37.8%; n = 14) followed by the environment (24.3%; n = 9). Both human and chicken isolates showed similar patterns of multidrug resistance to tested antimicrobials with a positive correlation (ρ = 0.91). Among ESBL producers, we observed the dissemination of blaCTX-M (10.8%; n = 4) genes. The coexistence of blaCTX-M-15 and blaTEM-1 genes was observed in 8.1% (n = 3) of the isolates, out of which (66.7%; n = 2) were chicken isolates from the farm, while a single human isolate was from the chicken market.

Conclusions: ESBL-EC isolates were prevalent amongst apparently healthy individuals, chickens and the poultry farm/market environment in Abuja. It is important to educate healthcare workers that people in proximity with poultry are a high-risk group for faecal carriage of ESBL-EC, hence pose a higher risk to the general population for the spread of antimicrobial resistance.

Keywords: Antimicrobial resistance; Chicken; Escherichia coli; Extended-spectrum β-lactamases (ESBL); Nigeria.

Fig. 1

Map of Abuja showing the distribution of ESBL-EC human, chicken and environmental isolates from farms and chicken markets. This map highlights five out of six area councils in Abuja, Federal Capital Territory namely: Bwari, Kwali, Kuje, Gwagwalada and Municipal area councils. Our study was done at two area councils (Kuje and Municipal area councils) with the highest volume of poultry production in Abuja. Each dot represents an ESBL-EC isolate obtained either from humans, chickens or the environment (Source of the Map is the Federal Ministry of Agriculture and Rural Development, Abuja, Nigeria)

Fig. 2

Proportion of ESBL-EC among positive E. coli isolates from humans, chickens, and poultry environment in Abuja, Nigeria, 2019. The number of E. coli positive isolates are plotted as bars on the primary axis while the proportion of these positive isolates which are ESBL-EC in percentages are plotted as a line graph on the secondary axis. The various data points on the line graph are also displayed on the chart

Fig. 3

Prevalence of ESBL-EC isolated from humans, chickens and poultry environment, Abuja, Nigeria, 2019. Bars represent the proportion of ESBL-EC isolates from each isolation source with 95% confidence intervals. Error bars represent Standard Error of the mean prevalence. Data were obtained from two sources: poultry farms and poultry markets

Fig. 4

Multilocus Sequence Types for ESBL-EC isolated from humans, chickens and poultry environment, Abuja, Nigeria, 2019. Each bar represents the various ESBL-EC sequence types for isolates obtained from humans, chickens and chicken farm/market environments