Resistance to ciprofloxacin in pathogenic Enterobacteriaceae in England and Wales in 1996

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Updated: Oct 30, 2026

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

E J Threlfall1, A Graham, T Cheasty

  • 1Laboratory of Enteric Pathogens, Central Public Health Laboratory, London, UK.

Journal of Clinical Pathology
|March 28, 1998
PubMed

Insights

Ciprofloxacin resistance in Escherichia coli and Salmonella is increasing. Physicians should consider laboratory sensitivity tests before treatment, especially for invasive infections, due to rising resistance levels.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Ciprofloxacin is a widely used antibiotic.
  • Antimicrobial resistance is a growing global health concern.
  • Monitoring resistance patterns is crucial for effective treatment.

Purpose of the Study:

  • To assess the prevalence of ciprofloxacin resistance in key bacterial pathogens.
  • To evaluate the clinical implications of ciprofloxacin resistance.
  • To recommend updated laboratory testing breakpoints.

Main Methods:

  • Analysis of bacterial isolates from 1996.
  • Determination of minimum inhibitory concentrations (MICs) for ciprofloxacin.
  • Comparison of resistance rates across different bacterial species.

Main Results:

  • 6% of *Escherichia coli* from extraintestinal infections showed high-level ciprofloxacin resistance (MICs ≥ 2 mg/l).
  • Low-level ciprofloxacin resistance (MICs 0.125-1 mg/l) was observed in *Salmonella* species (7% *S. typhi*, 4% *S. paratyphi A*, 4% non-typhoidal *Salmonella*).
  • Ciprofloxacin resistance was infrequent in *Shigella* species.

Conclusions:

  • Physicians should be aware of potential ciprofloxacin treatment failures in invasive *E. coli* infections before susceptibility results are known.
  • Increasing treatment failures in salmonellosis are linked to low-level ciprofloxacin resistance.
  • A breakpoint of 0.125 mg/l for ciprofloxacin susceptibility testing in Enterobacteriaceae is recommended due to rising resistance.

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