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Reduced virulence in ciprofloxacin-resistant variants of Pseudomonas aeruginosa strains
G Ravizzola1, F Pirali, A Paolucci
1Institute of Microbiology, University of Brescia, Italy.
The Journal of Antimicrobial Chemotherapy
|December 1, 1987
Abstract:
Pseudomonas aeruginosa strains resistant to ciprofloxacin were obtained from parental strains by serial transfer through subinhibitory concentrations of the drug. They showed reduced virulence for mice, and also increased sensitivity to aminoglycosides.
Insights
Ciprofloxacin resistance in Pseudomonas aeruginosa strains led to decreased virulence in mice and increased susceptibility to aminoglycoside antibiotics. This suggests a potential trade-off between antibiotic resistance and bacterial pathogenicity.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen known for its intrinsic and acquired antibiotic resistance.
- Ciprofloxacin, a fluoroquinolone antibiotic, is commonly used to treat P. aeruginosa infections.
- Mechanisms of antibiotic resistance can sometimes impact bacterial fitness and virulence.
Purpose of the Study:
- To investigate the phenotypic changes in Pseudomonas aeruginosa strains upon development of ciprofloxacin resistance.
- To assess the impact of acquired ciprofloxacin resistance on bacterial virulence in a murine model.
- To determine if ciprofloxacin resistance influences susceptibility to other antibiotic classes, specifically aminoglycosides.
Main Methods:
- Induction of ciprofloxacin resistance through serial passage of P. aeruginosa in subinhibitory drug concentrations.
- Assessment of bacterial virulence using a mouse infection model.
- Evaluation of antibiotic susceptibility profiles, focusing on aminoglycosides, for resistant strains.
Main Results:
- Ciprofloxacin-resistant P. aeruginosa strains were successfully generated.
- These resistant strains exhibited significantly reduced virulence compared to their parental strains in the mouse model.
- The ciprofloxacin-resistant strains displayed an unexpected increase in sensitivity to aminoglycoside antibiotics.
Conclusions:
- Acquisition of ciprofloxacin resistance in P. aeruginosa may impose a fitness cost, manifesting as reduced virulence.
- Cross-resistance or collateral sensitivity patterns were observed, with resistance to one drug class altering susceptibility to another.
- These findings have implications for antimicrobial stewardship and treatment strategies for multidrug-resistant P. aeruginosa infections.