Health and economic outcomes of the detection of Klebsiella pneumoniae-produced extended-spectrum beta-lactamase (ESBL) in a hospital with high prevalence of this infection

Abstract

Introduction: Klebsiella pneumoniae is of high prevalence in hospital infections, mainly in bloodstream infections (BSI), and some produce extended-spectrum beta-lactamase (ESBL). for hospitals with a high prevalence of strains producing this enzyme, there is no reference material to show whether the use of the E-test method for their detection, which can be quite expensive, is actually required.Objective: To evaluate the cost-benefit of the disk diffusion and E-test methods for the detection of ESBL-producing K. pneumoniae strains in hospitals where a high prevalence of this resistance mechanism in BSI is found.Methods: One hundred and eight patients with K. pneumoniae BSI were evaluated retrospectively. ESBL-producing strains were identified by the disk diffusion method and by the E-test method. We estimated the costs of both diagnostic methods based on antimicrobial therapy adequacy.Results: Fifty-two percent of K. pneumoniae infections were due to ESBL-producing strains. the disk diffusion method yielded a positive predictive value (PPV) of 94.7% (95% Cl: 88.9-100%) and a negative predictive value (NPV) of 96.1% (CI 95%: 90.8-101.4%) in relation to the E-test. We evaluated cost-effectiveness, i.e., we analyzed the cost of both E-test and disk diffusion methods with carbapenem and cephalosporins, and found that the use of the disk diffusion method accounts for approximately US$3300.Conclusions: in hospitals with a high prevalence of ESBL-producing strains, the disk diffusion method can be used to detect ESBL-producing K. pneumoniae without compromising the clinical progression of patients with BSI. the E-test showed higher accuracy but this method was more expensive than the disk diffusion method. However, the use of the E-test method was demonstrated to be more cost-effective, as we evaluated cost based on antimicrobial therapy adequacy. (C) 2005 International Society for Infectious Diseases. Published by Elsevier B.V. All rights reserved.