[Carbapenem resistance in Pseudomonas aeruginosa isolated from urine cultures: prevalence and risk factors]

OBJECTIVE

Pseudomonas aeruginosa is a non-fermentative gram-negative bacillus with a great ability to develop resistance to multiple antibiotics, including carbapenems, which is a growing problem worldwide. The aim of this study was to analyse the prevalence of carbapenem-resistant P. aeruginosa (CRPA) in urine cultures and to determine the risk factors associated with the development of carbapanem resistance.

METHODS

Positive urine cultures to P. aeruginosa between September 2012 and September 2014 were identified. We excluded repetitive cultures from the same patient. We created a database with different variables, including antimicrobial resistance. The prevalence of carbapenem resistance and the risk factors for growth of CRPA were analysed.

RESULTS

Ninety-one patients with positive urine cultures to P. aeruginosa were included. The prevalence of CRPA was 22%. The risk factors to CRPA infection in the univariate analysis were: congestive heart failure (p=0.02), previous treatment with ampicillin (p=0.04), meropenem (p=0.04), piperacillin-tazobactam (p=0.01), trimethoprim-sulfamethoxazole (p= 0.01) and previous treatment with more than one antibiotic (p<0.01). Only congestive heart failure (p<0.01) and previous treatment with more than one antibiotic (p<0.01) showed statistically significant differences in the multivariate analysis.

CONCLUSIONS

The prevalence of CRPA in urine cultures is high in our population. We should assess the presence of risk factors as previous treatment with more than one antibiotic or comorbidities such as heart failure, in order to select an appropriate empirical treatment in patients with severe urinary tract infections.