Prevalence and antimicrobial resistance profiles of faecal Escherichia coli isolates from local chickens in Plateau State, Nigeria

Background: Poultry is a profitable business in Nigeria, with economic benefits to families and communities involved in this type of agriculture. However, infection of poultry birds by Escherichia coli can, in addition to causing mortality, results in reduction of egg production, with depletion of protein (egg and meat) and subsequent reduction in market value, consumer supply, cost of veterinary care, and medicines. The objectives of this study are to determine the prevalence and antimicrobial resistance profiles of faecal E. coli isolates from local chickens (Gallus domesticus) in Plateau State, northcentral Nigeria.

Methodology: This was a descriptive cross-sectional study of 540 local chickens for faecal carriage of E. coli, randomly selected from 9 local government areas (LGAs) (60 per LGA) in the 3 senatorial districts (180 per senatorial district) of Plateau State, Nigeria. Faecal samples were collected from the chickens for culture isolation and identification of E. coli using conventional microbiological methods. The isolates were confirmed by Vitek® 2 compact machine and PCR amplification of 16S rRNA gene. Antibiotic susceptibility test of 37 distinct E. coli strains to selected antibiotics (ampicillin, ampicillin/sulbactam, piperacillin, cefazolin, cefepime, ceftriaxone, ceftazidime, cefoxitin, ertapenem, meropenem, amikacin, gentamicin, tobramycin, ciprofloxacin, levofloxacin, nitrofurantoin and trimethoprim/sulfamethoxazole) was performed by the Vitek® 2 and read using the web system application. Data analysis was performed using the Statistical Package for the Social Sciences (SPSS) version 20.0 and R Commander version 2.9-1.

Results: The overall prevalence of faecal E. coli carriage among the chickens was 65.0% (351/540), with highest prevalence in Central Plateau senatorial district (76.1%, 137/180), which was significantly higher than Northern Plateau (62.2%, 112/180) and Southern Plateau (56.7%, 102/180) (x2=15.873, p=0.0004). The prevalence of E. coli was highest in Pankshin (86.7%, 52/60) and Mangu (85.0%, 51/60) LGAs and this was significantly higher than in Bokkos (56.7%, 34/60) (x2=18.761, p<0.000) and other LGAs. The antibiotic susceptibility of 37 distinct strains of E. coli showed that 64.9% (n=24) were resistant to at least one antibiotic, with the highest resistance rate being to trimethoprim-sulfamethoxazole (51.4%, n=19), ampicillin (48.7%, n=18), and piperacillin (43.2%, n=15). Multi-drug resistance (resistance to three or more antibiotic classes) was observed in 35.1% (n=13) of the E. coli strains. The multiple antibiotic resistance (MAR) index ranged from 0.06 (resistance to one antibiotic) to 0.76 (resistance to 13 antibiotics tested).

Conclusion: The results of this study provide evidence that resistance to multiple antibiotics is widespread among faecal E. coli isolates from local chickens in Plateau State, Nigeria, and thus poses potential risks for human infections with MDR E. coli.

Keywords: local chicken; faecal carriage; Escherichia coli, multi-drug resistance; zoonosis

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Prevalence and antimicrobial resistance profiles of faecal Escherichia coli isolates from local chickens in Plateau State, Nigeria