Purpose:
Carbapenems are important agents for the therapy of Gram-negative bacillus infections, and the development of their resistance hampers effective therapeutic options. The purpose of this study was to assess the major mechanisms and risk factors leading to carbapenem resistance in clinical Pseudomonas aeruginosa isolates.
Methods:
Thirty-four clinical isolates with differing degrees of carbapenem susceptibility were analyzed for carbapenemase, porin, and efflux systems. Risk factor analysis was performed using a case–control study.
Results:
Eighteen of 24 carbapenem-resistant isolates were producers of carbapenemase. Diminished expression of oprD and overexpression of effluxes were present in five and seven carbapenem-resistant isolates, respectively. The number of days from admission to the day of positive culture and days of antibiotic apply were identified as the independent predictors of infection with carbapenem-resistant P. aeruginosa.
Conclusions:
Carbapenemase production is a major mechanism of P. aeruginosa isolates involved in this study. Increased length of hospital stay and days of antibiotic application were the most important risk factors identified for carbapenem resistance.
