Foodborne nosocomial outbreak of SHV1 and CTX-M-15-producing Klebsiella pneumoniae: Epidemiology and control

Abstract

Background. We describe a foodborne nosocomial outbreak due to extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae.Methods.An outbreak of ESBL K. pneumoniae was detected in March 2008. Initial control measures included contact isolation and a protocol for routine detection and reinforcement in hand hygiene practices. ESBL producers were screened for the blaTEM, blaSHV, and blaCTX-M genes. Pulsed-field gel electrophoresis analysis was performed using XbaI as a restriction endonuclease.Results. One hundred fifty-six colonized and/or infected patients were identified, 35 (22.4%) of whom had infection. The outbreak affected all hospital wards. Fecal carriage was up to 38% of patients in some wards. Of note, investigation revealed a very short delay between admission and colonization. None of the health care workers or environmental surfaces in the wards was found to be colonized. This prompted an epidemiological investigation of a possible foodborne transmission. We found that up to 35% of the hospital kitchen-screened surfaces or foodstuff were colonized and that 6 (14%) of 44 food handlers were found to be fecal carriers. Phenotypic and genotypic analysis of all clinical, environmental, and fecal carrier isolates showed the dissemination of a single strain of SHV-1 and CTX-M-15-producing K. pneumoniae. At that time, structural and functional reforms in the kitchen were performed. These were followed by a progressive reduction in colonization and infection rates among inpatients until complete control was obtained in December 2008. No restrictions in the use of antibiotics were needed.Conclusions. To our knowledge, this is the first reported hospital outbreak that provides evidence that food can be a transmission vector for ESBL K. pneumoniae. © 2011 The Author.