A silent outbreak due to Klebsiella pneumoniae that co-produced NDM-1 and OXA-48 carbapenemases, and infection control measures

OBJECTIVE(S): Infections due to carbapenemase-producing Klebsiella pneumoniae are associated with high morbidity and mortality. In this study, we report a hospital outbreak due to co-producing OXA-48 and NDM-1 K. pneumoniae clone. The aim of the study is to investigate the clonal relationship of strains, risk factors of outbreak and infection control measures. MATERIALS AND METHODS: Once an outbreak was suspected at the end of December 2017 in our intensive care unit (ICU), carbapenem resistance K. pneumoniae identified in patients’ specimens. An outbreak analysis was begun to determine the risk factors and dissemination of the cases. A case-control study was conducted to determine the risk factors. To control the outbreak; tight contact prevention, good clean-up the medical devices and hospital environment, were done. Staff training programs such as hand hygiene, disinfection, wearing aprons, good cleaning were created. Carbapenem resistance genes determined by PCR. Clonal relationships of strains investigated by PFGE. RESULTS: We investigate 21 carbapenem-resistant K. pneumonia strains. Nine of them were found co-produced NDM-1 and OXA-48, 11 strains produced OXA-48, and one strain produced NDM-1. Seven strains of co-producing NDM-1 and OXA-48 were found clonally related with PFGE. We could not determine any risk factor except rectal colonization in the case-control study. CONCLUSION: The interventions that successfully controlled this outbreak were hand hygiene, tight contact prevention, good clean-up of the hospital environment and medical devices. As a result, we believe that it would be beneficial to take infection control measures to prevent the spread of these strains to the community and hospital settings.