[Risk factors associated with the isolation of extended spectrum betalactamases producing Escherichia coli or Klebsiella pneumoniae in a tertiary care hospital in Colombia].

INTRODUCTION: Extended-spectrum beta-lactamases (ESBL) are an emerging resistance phenomenon with particular incidence in Latin America. In Colombia there is very little information regarding the risk factors associated with its acquisition.

OBJECTIVE: To determine the risk factors that are associated with infection or colonization by Escherichia coli or Klebsiella pneumoniae producing ESBL in patients older than 18 years.

MATERIALS AND METHODS: A case-control study, ratio 1:1, in patients with an isolate from any sample of E. coli or K. pneumoniae producing ESBL in the period from January 2009 to November 2011 at San José University Hospital in Bogotá (Colombia).

RESULTS: We studied 110 cases and 110 controls, 62.7% were E. coli and 37.3% K. pneumoniae . In the multivariate analysis the independent risk factors found were: chronic renal failure (odds ratio [OR] 2.99, confidence interval 95% [95% CI] 1.10-8.11, p=0.031), urologic surgery (OR 4.78 95% CI 1.35 to 16.87, p=0.015), history of antibiotic use in the previous three months (OR 2.24, 95% CI 1.09 – 4.60, p=0.028), nosocomial origin of infection (OR=2.92 95% CI 1.39 – 6.13, p=0.004) and previous hospitalization (OR 1,59, 95% CI=1.03 – 2.46, p=0,036).

CONCLUSION: Anticipating the resistance pattern of the organism infecting a patient based on risk factors may allow the choice of appropriate empirical antibiotic therapy, which will have an impact on reducing patients' morbidity and mortality.