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Chromosomal and plasmid-mediated fluoroquinolone resistance in human Salmonella enterica infection in Ghana.

Published version
Peer-reviewed

Type

Article

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Authors

Acheampong, Godfred 
Owusu, Michael 
Owusu-Ofori, Alex 
Osei, Isaac 
Sarpong, Nimako 

Abstract

BACKGROUND: Salmonella infection poses significant public health threat globally, especially in resource-limited countries. Emergence and spread of antibiotic resistant strains to fluoroquinolones have led to treatment failures and increased mortality in Salmonella infection. However, there is dearth of information regarding mechanisms of resistance to fluoroquinolones in Ghana. This study therefore sought to identify chromosomal mutations and plasmid-mediated resistance as possible mechanisms of fluoroquinolone resistance from clinical isolates in Ghana. METHODS: This was a retrospective study of archived isolates biobanked at Kumasi Centre for Collaborative Research in Tropical Medicine, Ghana. Isolates were obtained from blood, stool and oropharynx samples at two hospitals, between May, 2016 and January, 2018. Salmonella identification was done using standard microbiological protocols and antibiotic susceptibility testing performed by Kirby-Bauer disc diffusion method. Isolates with intermediate susceptibility and/or resistance to nalidixic acid and/or ciprofloxacin were selected and examined for chromosomal mutations by Sanger sequencing and plasmid-mediated resistance by PCR. RESULTS: Of 133 biobanked isolates cultured, 68 (51.1%) and 16 (12%) were identified as Salmonella Typhi and non-typhoidal Salmonella (NTS), respectively. Sequence analysis of gyrA gene revealed the presence of 5 different nonsynonymous mutations, with the most frequent mutation (Ile203Ser) occurring in 12 out of 13 isolates tested. Gyrase B (gyrB) gene had 1 nonsynonymous mutation in 3 out of 13 isolates, substituting phenylalanine with leucine at codon 601 (Phe601Leu). No mutation was observed in parC and parE genes. Two NTS isolates were found to harbour qnrS plasmid-mediated resistant gene of molecular size 550 bp with high ciprofloxacin MIC of 0.5 μg/ml. CONCLUSION: This study reports for the first time in Ghana plasmid-mediated fluoroquinolone resistant gene qnrS in Salmonella clinical isolates. Nonsynonymous mutations of gyrA and gyrB genes likely to confer Salmonella reduced susceptibility to ciprofloxacin were also reported.

Description

Keywords

Fluoroquinolone resistance, Mutations, Plasmids, Salmonella enterica, Adolescent, Anti-Bacterial Agents, Child, Preschool, Ciprofloxacin, DNA Gyrase, DNA Topoisomerase IV, Disk Diffusion Antimicrobial Tests, Drug Resistance, Bacterial, Female, Fluoroquinolones, Genes, Bacterial, Ghana, Humans, Male, Mutation, Plasmids, Retrospective Studies, Salmonella Infections, Salmonella enterica, Young Adult

Journal Title

BMC Infect Dis

Conference Name

Journal ISSN

1471-2334
1471-2334

Volume Title

19

Publisher

Springer Science and Business Media LLC