Colistin and tigecycline susceptibility among multidrug-resistant Acinetobacter baumannii isolated from
M Dizbay1, A Altuncekic, B Ergut Sezer
1Gazi University Faculty of Medicine, Department of Clinical Microbiology and Infectious Diseases, Besevler, Ankara, Turkey. muratdizbay@gazi.edu.tr
Abstract:
Multidrug-resistant (MDR) Acinetobacter baumannii is one of the most important pathogens in intensive care units related to morbidity and mortality, especially in ventilator-associated pneumonia (VAP). In this study, 80.5% of isolates were MDR. The antimicrobial susceptibilities for 12 different antibiotics of MDR A. baumannii isolated from VAP were tested. Among the MDR A. baumannii isolates, resistance rates were found to be 95.5%, 72.7%, 80.3%, 71.2% and 68.2% for ciprofloxacin, cefepime, imipenem, meropenem and cefoperazone/sulbactam, respectively. Netilmicin resistance was detected in 30.3% of the isolates. Resistance rates for colistin and tigecycline were 0% and 25.8%, respectively. It is obvious that new alternative drugs are needed for the treatment of MDR A. baumannii-related VAP owing to high resistance to carbapenems, quinolones, aminoglycosides and cefoperazone/sulbactam. Although colistin appears to be a good choice, adverse reactions and unavailability of colistin limit its wide usage in Turkey. Tigecycline, which will shortly be introduced commercially in Turkey, is very effective against MDR A. baumannii isolates and shows promising results to solve the problem, however resistance rates should be monitored closely.
Insights
Multidrug-resistant Acinetobacter baumannii causes significant mortality in intensive care units. High resistance rates necessitate new treatments, with tigecycline showing promise but requiring careful monitoring.
Area of Science:
- Infectious Diseases
- Microbiology
- Critical Care Medicine
Background:
- Multidrug-resistant (MDR) Acinetobacter baumannii is a critical pathogen in intensive care units, frequently causing ventilator-associated pneumonia (VAP).
- High rates of MDR A. baumannii contribute significantly to patient morbidity and mortality.
- The emergence of resistance to common antibiotics poses a major therapeutic challenge.
Purpose of the Study:
- To evaluate the antimicrobial susceptibility patterns of MDR A. baumannii isolates from VAP patients.
- To identify effective alternative treatment options for MDR A. baumannii-related VAP.
- To assess the potential of colistin and tigecycline as treatment options.
Main Methods:
- Antimicrobial susceptibility testing was performed on 80.5% MDR A. baumannii isolates from VAP patients against 12 different antibiotics.
- Resistance rates for specific antibiotics including ciprofloxacin, cefepime, carbapenems (imipenem, meropenem), cefoperazone/sulbactam, netilmicin, colistin, and tigecycline were determined.
- Clinical data on the usage and limitations of colistin and the introduction of tigecycline in Turkey were considered.
Main Results:
- High resistance rates were observed for ciprofloxacin (95.5%), cefepime (72.7%), imipenem (80.3%), meropenem (71.2%), and cefoperazone/sulbactam (68.2%).
- Netilmicin resistance was 30.3%, while resistance to colistin was 0%.
- Tigecycline showed 25.8% resistance, indicating significant efficacy against most MDR A. baumannii isolates.
Conclusions:
- The high resistance to carbapenems, quinolones, aminoglycosides, and cefoperazone/sulbactam highlights the urgent need for alternative drugs to treat MDR A. baumannii VAP.
- Colistin is a viable option due to 0% resistance, but its use is limited by adverse effects and availability.
- Tigecycline demonstrates promising effectiveness, but continuous monitoring of resistance development is crucial for its sustained utility.
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