Surveillance of antibiotic susceptibility patterns among Shigella sonnei strains isolated in Belgium during the 18-year period 1990 to 2007

J Clin Microbiol. 2009 May;47(5):1379-85. doi: 10.1128/JCM.02460-08. Epub 2009 Mar 25.

Abstract

This study was conducted to determine the frequency and pattern of antimicrobial susceptibility of Shigella sonnei, the predominant species causing shigellosis in Belgium. Between 1990 and 2007, a total of 7,307 strains, mainly (98.2%) isolated from stools, were diagnosed by peripheral laboratories before being confirmed as Shigella strains by serotyping by the National Reference Center of Salmonella and Shigella. A significant increase in resistances to tetracycline, streptomycin, trimethoprim, sulfonamides, and cotrimoxazole (i.e., trimethoprim in combination with sulfonamides) was observed during this period. Since 1998, resistance to nalidixic acid also increased to reach a peak (12.8%) of resistant isolates in 2004. Concomitantly, multidrug resistance (MDR) in this species emerged in 2007, with 82% of total isolates being MDR. However, during this 18-year period, all isolates remained fully susceptible to ciprofloxacin and gentamicin. The work includes the molecular characterization of mechanisms of resistance to ampicillin, tetracycline, chloramphenicol, and cotrimoxazole and class 1 and class 2 integrons. S. sonnei acquired antimicrobial resistance to traditional antibiotics (ampicillin and tetracycline) by horizontal gene transfer, while the genetic stability of transposons was responsible for a high (89%) proportion of resistance to a commonly prescribed antibiotic (cotrimoxazole). Therefore, cotrimoxazole should no longer be considered appropriate as empirical therapy for treatment of shigellosis in Belgium when antibiotics are indicated. Rates of resistance to nalidixic acid should also be attentively monitored to detect any shift in fluoroquinolone resistance, because it represents the first line among antibiotics used in the treatment of shigellosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Belgium
  • Child, Preschool
  • DNA Transposable Elements
  • Drug Resistance, Bacterial
  • Dysentery, Bacillary / microbiology*
  • Gene Transfer, Horizontal
  • Humans
  • Infant
  • Microbial Sensitivity Tests
  • R Factors
  • Shigella sonnei / drug effects*
  • Shigella sonnei / isolation & purification

Substances

  • Anti-Bacterial Agents
  • DNA Transposable Elements