Prevalence of extended-spectrum beta-lactamases in Klebsiella pneumonia and Escherichia coli bacteremia

Aims: To evaluate the prevalence of extended-spectrum beta-lactamases (ESBL) production by Klebsiella pneumoniae and Escherichia coli isolated from hospitalized adult patients and to describe the patient's clinical characteristics. Methods: Through a cross-sectional study, all charts from adult patients that presented Klebsiella pneumoniae and Escherichia coli bacteremia in Hospital Sao Lucas da PUCRS, from June 2004 to March 2006, were revised. Results: A total of 145 patients were included in the study. Among them, 51 (35.2%) had an isolate of ESBLproducing bacteria. The prevalence of ESBL was higher in Klebsiella pneumoniae (45 isolates, 55.6%) than in Escherichia coli (6 isolates, 9.4% p< 0.001). The use of betalactamic antibiotics in the previous 14 days was commonest in the group ESBL-producing (50 pacients, 98%) than in the group no ESBL-producing (15 pacients, 16%); p< 0.001. Imipenem was the drug with better in vitro efficacy against ESBL-producing isolates (100%). Conclusions: The study demonstrated a high prevalence of ESBL-producing K. pneumoniae bacteremias. Patients with bacteremia by ESBL-producing isolates had higher mortality, and previous use of betalactamic antibiotics was stongly associated to this enzyme production. Continuous surveillance of ESBL-producing Enterobacteriacae prevalence is necessary for definition of therapeutic measures and infection control policies.