Related Experiment Videos
Evolution of resistance among clinical isolates of Acinetobacter over a 6-year period
1Laboratory of Microbiology, Hospital Universitario Virgen de la Arrixaca, Murcia, Spain.
Abstract:
The aim of this report was to study the evolution of susceptibilities of 1532 clinical isolates of Acinetobacter recovered over a period of 6 years. The minimal inhibitory concentrations (MICs) of 15 antimicrobial agents were determined for all the isolates. The respective percentages of resistant strains in the years 1991 and 1996 were as follows: ciprofloxacin, 54.4% and 90.4%; tobramycin, 33% and 71.8%; amikacin, 21% and 83.7%; ampicillin plus sulbactam, 65.7% and 84.1%; ceftazidime, 57.4% and 86.8%; ticarcillin, 70% and 89.4%; trimethoprim plus sulfamethoxazole, 41.1% and 88.9%; and imipenem, 1.3% and 80%. The MIC90s of ciprofloxacin, sparfloxacin, biapenem, meropenem, imipenem, cefepime, cefpirome, and rifampicin against 250 imipenem-resistant Acinetobacter strains were >32, >32, 128, >256, 256, >256, 256, and 16 mg/l, respectively. With serious infections, it was necessary to resort to the use of colistin, the only antibiotic active in vitro.
Insights
Antimicrobial resistance in Acinetobacter strains significantly increased over six years. Colistin emerged as the only effective antibiotic for treating serious infections caused by these resistant bacteria.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Acinetobacter species are significant opportunistic pathogens.
- Increasing antimicrobial resistance poses a major threat to public health.
- Monitoring resistance trends is crucial for effective treatment strategies.
Purpose of the Study:
- To investigate the evolution of antimicrobial susceptibilities in clinical isolates of Acinetobacter.
- To determine the resistance patterns of Acinetobacter over a six-year period.
Main Methods:
- Analysis of 1532 clinical Acinetobacter isolates collected between 1991 and 1996.
- Determination of minimal inhibitory concentrations (MICs) for 15 antimicrobial agents.
- Evaluation of MIC90 values for specific antibiotics against imipenem-resistant strains.
Main Results:
- A dramatic increase in resistance percentages was observed for most tested antibiotics between 1991 and 1996.
- Resistance to ciprofloxacin rose from 54.4% to 90.4%, and to imipenem from 1.3% to 80%.
- Colistin was the only agent demonstrating consistent in vitro activity against serious Acinetobacter infections.
Conclusions:
- There has been a significant escalation in antimicrobial resistance among Acinetobacter clinical isolates.
- The study highlights the urgent need for new therapeutic strategies and emphasizes the critical role of colistin.
- Continuous surveillance of antimicrobial resistance patterns is essential for guiding clinical practice.