Risk Factors for Multi-Drug-Resistant Pseudomonas aeruginosa Infections in a University Hospital-A Case Control Study

Purpose: This study aims to determine the risk factors associated with multi-drug-resistant Pseudomonas aeruginosa (MDR-Pa) infections. Methods: A case control study was conducted at the Dicle University Hospital which is 1150-bed tertiary care teaching hospital in Diyarbakir, Turkey. The study cases were recruited from patients with nosocomial MDR-Pa infections. Two control cases were arranged to compare risk factors of MDR-Pa infections. One of the control groups was composed of patients with non-MDR-Pa infections and the other group with non-MDR Gram-negative bacterial infections except P. aeruginosa. Results: Overall, 225 patients were included in the study, 75 with MDR-Pa infections, 150 control cases (75 non-MDR-Pa and 75 MDR Gram-negative non P. aeruginosa infections). The incidence of MDR-Pa infections was found as 3.1/1,000 admissions. Multivariate analysis showed that multiple invasive procedures (Relative Risk 24.57 (95% Confidence Interval 4.45- 135.73) p<0.001), burn (RR 13.66 (CI 407-45.80) p<0.001), malignity (RR 12.50 (CI 2.64-59.20) p=0.001), pneumonia (RR 11.91 (CI 2.44-58.16) p=0.002), carbapenem use (RR 4.92 (CI 1.60-15.09) p=0.005) and long hospitalization (> 10 days) (RR 4.68 (CI=2.09-10.49) p<0.001), were found to be risk factors for MDR-Pa. Conclusions: This study revealed that severity of clinical course and carbapenem use are significant risk factors for MDR-Pa infections.