Increased Mortality Associated With a Clonal Outbreak of Ceftazidime-ResistantKlebsiella pneumoniae: A Case–Control Study

Abstract

Objectives: : To determine risk factors for ceftazidime-resistantKlebsiella pneumoniaeinfection and the effect of cef-tazidime-resistantK. pneumoniaeinfection on mortality during an isolated outbreak.Design: : Case–control investigation using clinical and molecular epidemiology and prospective analysis of infection control interventions.Setting: : Surgical intensive care unit of a university-affiliated community hospital.Patients: : Fourteen case-patients infected with ceftazidime-resistantK. pneumoniaeand 14 control-patients.Results: : Ten of 14 case-patients had identical strains by pulsed-field gel electrophoresis. Broad-spectrum antibiotic therapy before admission to the unit was strongly predictive of subsequent ceftazidime-resistantK. pneumoniaeinfection. In addition, patients with ceftazidime-resistantK. pneumoniaeinfection experienced increased mortality (odds ratio, 3.77).Conclusions: : Cephalosporin restriction has been shown to decrease the incidence of nosocomial ceftazidime-resistantK. pneumoniae. However, isolated clonal outbreaks may occur due to lapses in infection control practices. Reinstatement of strict handwashing, thorough environmental cleaning, and repeat education led to termination of the outbreak. A distinct correlation between ceftazidime-resistantK. pneumoniaeinfection and mortality supports the important influence of antibiotic resistance on the outcome of serious bacterial infections.