African Journal of
Pharmacy and Pharmacology

  • Abbreviation: Afr. J. Pharm. Pharmacol.
  • Language: English
  • ISSN: 1996-0816
  • DOI: 10.5897/AJPP
  • Start Year: 2007
  • Published Articles: 2195

Full Length Research Paper

Prevalence and gene sequencing of extended spectrum β-lactamases producing Salmonella enterica serovar. Typhi from South-East Nigeria

Nathaniel Ejikeme Onyenwe
  • Nathaniel Ejikeme Onyenwe
  • Department of Pharmaceutical Microbiology, Dora Akunyili College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria.
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Nnabuike Didacus Nnamani
  • Nnabuike Didacus Nnamani
  • Department of Pharmaceutics and Pharmaceutical Technology, Dora Akunyili College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria.
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Jude Chidi Okoro
  • Jude Chidi Okoro
  • Department of Pediatrics, College of Medicine, Imo State University Teaching Hospital, Owerri, Imo State, Nigeria.
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Chioma Nnenna Nwofor
  • Chioma Nnenna Nwofor
  • Department of Applied Microbiology and Brewing, Faculty of Bioscience, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
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Christiana Jesumirhewe
  • Christiana Jesumirhewe
  • Department of Pharmaceutical Microbiology, Dora Akunyili College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria.
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  •  Received: 04 January 2020
  •  Accepted: 28 May 2020
  •  Published: 31 August 2020

Abstract

Enteric fever is a systemic disease classified into typhoid and paratyphoid fever. Fluoroquinolones and third generation cephalosporins are usually the drugs of choice in the management of Salmonella infections. Previous reports have indicated common occurrence of multi-drug resistance (MDR) including resistance to β-lactams and fluoroquinolones. However, there is paucity of information on the genetic determinants of resistance to β-lactam and fluoroquinolones from S. enterica in Southeast Nigeria. Salmonella enterica serovars were identified and screened (25 each from unrelated patients from the four hospitals). Resistant isolates were screened for ESBL phenotypically. Genomic and plasmid DNA were extracted by boiling and alkaline lysis, respectively. PCR amplification of blaTEM, blaSHV and blaCTX-M, among the ESBL positive isolates and sequencing of the Quinolone Resistance Determining Regions (QRDR) on fluoroquinolone resistant isolates were determined. Of the 100 isolates, thirty six of the MDR isolates produced ESBL phenotypically, of which 13 were blaCTX-M positive. DNA sequencing revealed single point mutations in gyrA at amino acid positions Asp-87-Gly, Asp-87-Asn and Ser-83-Tyr in 55 (68.8%), and double mutation in parC at positions Asp-87-Gly in 14 (17.5%). Mutations in gyrA, parC genes, and chromosomal blaCTX-M were responsible for the fluoroquinolones and cephalosporins resistance, respectively in some of the Salmonella enterica from Southeast Nigeria. QRDR of the gyrA gene of the isolates sequenced showed reduced susceptibility to some fluoroquinolone. The taxonomic and neighbouring trees of similar species causing infection worldwide were identified, and hence, alleviates the fear of easy spreading of quinolone and cephalosporin resistant isolates.

Key words: Quinolone Resistance Determining Regions (QRDR), ESBL, S.enterica, mutation.