Verona Integron-Encoded Metallo-Beta-Lactamase-Producing Carbapenem-Resistant Enterobacteriaceae in a Neonatal and Adult Intensive Care Unit — Kentucky, 2015

BACKGROUND:   On August 11, 2015, the Kentucky Department for Public Health was notified of a neonate with a Verona integron-encoded metallo-beta-lactamase (VIM)-producing Carbapenem-resistant Enterobacteriaceae (CRE) positive culture in tertiary-care Hospital A. CRE are defined as any Enterobacteriaceae resistant to any carbapenem or possessing a carbapenemase. CRE infections lead to complicated patient outcomes. Colonization with a VIM-producing CRE has only been identified once previously at this hospital, in an adult patient during 2013, and has never been reported in neonates in the United States. The purpose of this investigation was to characterize colonization and prevent further spread of an emerging resistance mechanism.

METHODS:   Weekly active surveillance perirectal cultures were collected in all intensive care unit (ICU) patients at Hospital A. Colonization was defined as any laboratory-confirmed VIM-producing CRE isolate after initial negative surveillance culture, on or after August 1, 2015. We reviewed medical records, observed infection control procedures, and collected environmental samples. Isolates were typed using pulsed-field gel electrophoresis and whole genome sequence analysis.

RESULTS:  As of November 2015, 8 isolates—Enterobacter cloacae (4), Raoultella species (1), Escherichia coli (1), and Klebsiella pneumoniae (2)—were confirmed in 6 patients; all represented colonization, not clinical infection. Six isolates were reported in the neonatal ICU and 2 were reported in an adult surgical ICU. All VIM- plasmids belonged to the same incompatibility group, Inc A/C2. Multiple lapses in infection control were observed, including isolation procedures. Environmental samples were negative for VIM-producing CRE.

CONCLUSIONS:  The unusual resistance mechanism and single plasmid type across isolates suggests possible plasmid transmission to multiple species at the institution; no original source has been identified. Control measures focus on optimizing infection control practice.