Journal of Global Antimicrobial Resistance (Sep 2021)

Isolation and characterisation of colistin-resistant Enterobacterales from chickens in Southeast Nigeria

  • M.U. Anyanwu,
  • R. Marrollo,
  • M. Paolucci,
  • F. Brovarone,
  • P. Nardini,
  • K.F. Chah,
  • S.V.O. Shoyinka,
  • E. Carretto

Journal volume & issue
Vol. 26
pp. 93 – 100

Abstract

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ABSTRACT: Objectives: Resistance to colistin (CST) mediated by mobile genetic elements has had a broad impact worldwide. There is an intensified call for epidemiological surveillance of mcr in different reservoirs to preserve CST for future generations. In Nigeria, the poultry industry is a key livestock sector. This study was undertaken to screen putative colistin-resistant Enterobacterales (CST-r-E) from poultry birds in Southeast Nigeria and to determine the genetic relatedness of mcr-harbouring isolates. Methods: Faecal and cloacal swab samples (n = 785) were collected from chickens in 17 farms located in three contiguous states in Southeast Nigeria between March–November 2018. Following selective culture, CST-r-E were isolated. Confirmation of CST resistance, antimicrobial susceptibility testing, molecular detection of genes mcr-1 to mcr-10, multilocus sequence typing (MLST) and randomly amplified polymorphic DNA (RAPD) analysis were performed on the isolates. A questionnaire was distributed to investigate the knowledge about CST and its use of chicken farm caretakers. Results: Of the 785 samples evaluated, 45 (5.7%) were positive for 48 CST-r-E, among which 23 harboured the mcr-1 gene (22 Escherichia coli and 1 Klebsiella pneumoniae). In two E.coli isolates, a new allelic variant (mcr-1.22) was detected. RAPD analysis allowed the identification of 11 different fingerprints. MLST also revealed 11 STs, with 3 of them being novel. Conclusion: mcr has significantly spread in poultry birds of Southeast Nigeria, which poses a worrisome risk to veterinary and human health. Strategies to prevent indiscriminate use of CST in farms should be quickly adopted before CST resistance becomes a huge global health issue.

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