Risk factors for imipenem-resistant Pseudomonas aeruginosa: a comparative analysis of two case-control studies in...

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Hospital Epidemiology

Background:

• Hospital-acquired infections pose a significant threat to patient safety.
• The emergence of antibiotic-resistant bacteria, such as imipenem-resistant Pseudomonas aeruginosa (IRPA), is a growing global health concern.
• Identifying risk factors for IRPA acquisition is crucial for implementing effective control strategies.

Purpose of the Study:

• To assess the risk factors associated with the acquisition of imipenem-resistant Pseudomonas aeruginosa (IRPA) among hospitalized patients.
• To compare risk factors using two distinct case-control study designs with different control groups.
• To evaluate the impact of specific antibiotic exposures and clinical conditions on IRPA development.

Main Methods:

• Two case-control studies were conducted at a tertiary care hospital.
• Study 1 compared IRPA patients with randomly selected controls.
• Study 2 compared IRPA patients with imipenem-susceptible P. aeruginosa (ISPA) patients.
• Data on patient demographics, treatments, and clinical outcomes were analyzed.

Main Results:

• Carbapenem treatment, mechanical ventilation, and prior hospital admission were significant risk factors for IRPA in Study 1.
• An interaction between carbapenem and vancomycin use showed a substantially increased odds ratio for IRPA (OR 43.71).
• In Study 2, carbapenem exposure (OR 12.82) and renal failure (OR 5.00) were identified as key risk factors for IRPA.

Conclusions:

• Carbapenem exposure is confirmed as the primary risk factor for IRPA acquisition.
• Concomitant use of carbapenem and vancomycin significantly elevates the risk of IRPA.
• These findings underscore the importance of antibiotic stewardship programs to mitigate the spread of carbapenem-resistant organisms.