Serotype distribution and antimicrobial resistance of human Salmonella enterica in Bangui, Central African Republic, from 2004 to 2013

PLoS Negl Trop Dis. 2019 Dec 2;13(12):e0007917. doi: 10.1371/journal.pntd.0007917. eCollection 2019 Dec.

Abstract

Background: Limited epidemiological and antimicrobial resistance data are available on Salmonella enterica from sub-Saharan Africa. We determine the prevalence of resistance to antibiotics in isolates in the Central African Republic (CAR) between 2004 and 2013 and the genetic basis for resistance to third-generation cephalosporin (C3G).

Methodology/principal findings: A total of 582 non-duplicate human clinical isolates were collected. The most common serotype was Typhimurium (n = 180, 31% of the isolates). A randomly selected subset of S. Typhimurium isolates were subtyped by clustered regularly interspaced short palindromic repeat polymorphism (CRISPOL) typing. All but one invasive isolate tested (66/68, 96%) were associated with sequence type 313. Overall, the rates of resistance were high to traditional first-line drugs (18-40%) but low to many other antimicrobials, including fluoroquinolones (one resistant isolate) and C3G (only one ESBL-producing isolate). The extended-spectrum beta-lactamase (ESBL)-producing isolate and three additional ESBL isolates from West Africa were studied by whole genome sequencing. The blaCTX-M-15 gene and the majority of antimicrobial resistance genes found in the ESBL isolate were present in a large conjugative IncHI2 plasmid highly similar (> 99% nucleotide identity) to ESBL-carrying plasmids found in Kenya (S. Typhimurium ST313) and also in West Africa (serotypes Grumpensis, Havana, Telelkebir and Typhimurium).

Conclusions/significance: Although the prevalence of ESBL-producing Salmonella isolates was low in CAR, we found that a single IncHI2 plasmid-carrying blaCTX-M-15 was widespread among Salmonella serotypes from sub-Saharan Africa, which is of concern.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Central African Republic / epidemiology
  • Drug Resistance, Bacterial*
  • Genes, Bacterial
  • Genotype
  • Genotyping Techniques
  • Humans
  • Plasmids / analysis
  • Prevalence
  • Retrospective Studies
  • Salmonella Infections / epidemiology*
  • Salmonella enterica / classification*
  • Salmonella enterica / drug effects*
  • Salmonella enterica / genetics
  • Salmonella enterica / isolation & purification
  • Serogroup*

Substances

  • Anti-Bacterial Agents

Grants and funding

The French National Reference Centre for E. coli, Shigella, and Salmonella is funded by the Institut Pasteur and Santé Publique France. The Unit for Pathogenic Enteric Bacteria is part of the Integrative Biology of Emerging Infectious Diseases Laboratory of Excellence funded by the French Government “Investment in the Future” programme (Grant no. ANR-10-LABX-62-IBEID, https://anr.fr/en/investments-for-the-future/investments-for-the-future/). This project was supported by the WHO Laboratory twinning initiative “Improvement of diagnostic and surveillance capacity for Salmonella in the Central African Republic” (WHO reference grant 2011/178985-0). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.