Outbreak ofKlebsiella pneumoniaeCarbapenemase–ProducingCitrobacter freundiiat a Tertiary Acute Care Facility in Miami, Florida

Abstract

OBJECTIVETo describe the investigation and control of a rare cluster ofKlebsiella pneumoniaecarbapenemase–producingCitrobacter freundiiin a hospital in southern Florida.METHODSAn epidemiologic investigation, review of infection prevention procedures, and molecular studies including whole genome sequencing were conducted.RESULTSAn outbreak ofK. pneumoniaecarbapenemase–3-producingC. freundiiwas identified at a tertiary hospital in Florida in 2014. Of the 6 cases identified, 3 occurred in the same intensive care unit and were caused by the same clone. For 2 of the 3 remaining cases, the isolates had low carbapenem minimum inhibitory concentrations and were unrelated by whole genome sequencing. As a response to the outbreak, supplementary environmental cleaning was implemented, including closure and terminal cleaning of the unit where the 3 cases clustered, in addition to the infection control bundle already in place at the time. No further cases were identified after these additional interventions.CONCLUSIONSAlthoughC. freundiiis not a species that commonly demonstrates carbapenem resistance, our findings suggest that carbapenemase-producingC. freundiimay be underdetected even when active surveillance is in place and has a potential to cause hospital outbreak.Infect Control Hosp Epidemiol2017;38:320–326