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Risk factors associated with the isolation of colistin-resistant gram-negative bacteria: a matched case-control study
Dimitrios K Matthaiou1, Argyris Michalopoulos, Petros I Rafailidis
1Alfa Institute of Biomedical Sciences, Athens, Greece.
Objective:
The emergence of multidrug-resistant gram-negative bacteria has led to the re-use of colistin, but resistance to this agent has already been reported. We aimed to investigate the potential risk factors for the isolation of colistin-resistant Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa from hospitalized patients.
Design:
Matched case-control study.
Setting:
Tertiary care hospital in Athens, Greece.
Patients:
Case patients were those who had provided a clinical specimen from which a colistin-resistant K. pneumoniae, A. baumannii, or P. aeruginosa was isolated. Controls were selected from a pool of patients who had susceptible to colistin isolates and were matched (1:1) to cases for species of microorganism and site of isolation. Susceptibility to colistin was determined with the Etest.
Interventions:
None.
Measurements And Main Results:
Data regarding patient demographics, comorbidities, admission to the intensive care unit, prior antibiotic use, and invasive procedures performed were analyzed as risk factors in a matched bivariable model. Variables significantly associated with colistin-resistant isolates (p < .05) were entered in a backward multivariable logistic regression model. Forty-one colistin-resistant unique patient isolates were identified from January 1, 2006, until March 31, 2007. These isolates represented infection in 35 of 41 patients. Risk factors significantly associated with the isolation of colistin-resistant isolates were age, duration of intensive care unit stay, [corrected] surgical procedures, use of colistin, use of monobactams, duration of use of colistin and duration of use of antifungal agents [corrected] In the multivariable model, use of colistin was identified as the only independent risk factor (adjusted odds ratio = 7.78, p = .002).
Conclusions:
Colistin-resistant K. pneumoniae, A. baumannii, and P. aeruginosa pathogens may be encountered in clinical practice, in association with inappropriate colistin use. To prevent this phenomenon, colistin should be used judiciously, given that treatment options for colistin-resistant gram-negative bacteria are limited.
Insights
Colistin resistance in gram-negative bacteria is a growing concern. Judicious use of colistin is crucial to prevent the emergence of resistant Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- The rise of multidrug-resistant gram-negative bacteria necessitates the re-use of colistin.
- Colistin resistance has emerged, posing a significant threat to patient care.
- Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are key pathogens exhibiting colistin resistance.
Purpose of the Study:
- To identify potential risk factors associated with colistin-resistant Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa.
- To investigate the clinical factors contributing to the isolation of these resistant pathogens in hospitalized patients.
Main Methods:
- A matched case-control study was conducted.
- Patients with colistin-resistant isolates (cases) were matched 1:1 with patients having colistin-susceptible isolates (controls).
- Data on demographics, comorbidities, ICU stay, and antibiotic use were analyzed using logistic regression.
Main Results:
- Forty-one colistin-resistant isolates were identified between January 2006 and March 2007.
- Significant risk factors included older age, longer ICU stays, surgical procedures, and prior use of colistin, monobactams, and antifungal agents.
- The multivariable model identified the use of colistin as the sole independent risk factor (adjusted odds ratio = 7.78, p = .002).
Conclusions:
- Colistin-resistant K. pneumoniae, A. baumannii, and P. aeruginosa are clinical concerns.
- Inappropriate colistin use is strongly associated with the emergence of resistance.
- Judicious colistin administration is essential due to limited alternative treatment options for resistant infections.
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