The effect of inappropriate therapy on bacteremia by ESBL-producing bacteria.

ABSTRACT

OBJECTIVE: To describe the impact of empiric appropriate treatment and the risk factors associated with mortality in patients with bacteremia by E. coli, K. pneumoniae and P. mirabilis producing ESBL. METHODS: Data were reviewed in an 8-year retrospective study, and 128 bacteremias were found 80 caused by E. coli (62.5%), 28 by K. pneumoniae (21.9%) and 20 by P. mirabilis (18.6%). RESULTS: The initial antibiotic treatment, administered within 72 h after the first positive blood culture, was appropriate with carbapenems or other antimicrobial agents with documented in vitro sensitivity in 53.8 and 16% of patients, respectively. The overall mortality 21 days after diagnosis was 17.2%, and it was 14.9 and 35.2% for patients adequately and inadequately treated, respectively. At univariate analysis the p value for mortality with and without appropriate treatment was 0.05, and significant differences were found only for previous positive blood cultures (p = 0.004) and presence of septic shock at diagnosis (p = 0.006). CONCLUSION: In this case series there was a high rate of initial appropriate empiric treatment, and only a marginal impact on mortality was found with regard to appropriate and inappropriate treatment. This report shows that the knowledge of ESBL-producing characteristics varies widely among the different case series for reasons that still have to be clarified.