Shigella species epidemiology and antimicrobial susceptibility: the implications of emerging azithromycin resistance for guiding treatment, guidelines and breakpoints

J Antimicrob Chemother. 2017 Nov 1;72(11):3181-3186. doi: 10.1093/jac/dkx268.

Abstract

Objectives: To examine antimicrobial susceptibility patterns and predictors of resistance among Shigella isolates in New South Wales (NSW), Australia during 2013-14 with emphasis on azithromycin.

Methods: Cross-sectional analysis of all shigellosis cases (160) notified to public health authorities in NSW, Australia was performed.

Results: Among 160 Shigella isolates tested, 139 (86.9%) were susceptible to azithromycin, 104 (65.0%) to ciprofloxacin and 38 (23.7%) to co-trimoxazole. Ciprofloxacin resistance was 1.9 times more common in infections acquired in Australia compared with those acquired overseas, while azithromycin resistance was 8.5 times more common in males.

Conclusions: We recommend ongoing reconsideration of guidelines for the treatment of shigellosis based on emerging resistance patterns. First-line therapy may need to be reconsidered based on local resistance rates due to common resistance to co-trimoxazole and ciprofloxacin. We recommend culture and susceptibility testing for suspected and proven shigellosis. Azithromycin susceptibility breakpoints for Shigella species may need to be species specific.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Australia / epidemiology
  • Azithromycin / pharmacology*
  • Azithromycin / therapeutic use
  • Child
  • Child, Preschool
  • Ciprofloxacin / pharmacology
  • Ciprofloxacin / therapeutic use
  • Cross-Sectional Studies
  • Drug Resistance, Multiple, Bacterial*
  • Dysentery, Bacillary / drug therapy
  • Dysentery, Bacillary / epidemiology*
  • Dysentery, Bacillary / microbiology*
  • Female
  • Humans
  • Logistic Models
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • New South Wales / epidemiology
  • Practice Guidelines as Topic
  • Shigella / drug effects*
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Ciprofloxacin
  • Azithromycin