ADS 29 - Possible Transmission of Klebsiella Pneumoniae Carbapenemase (KPC)-Producing Citrobacter Freundii in a Healthcare System

Background: From March 2022 – October 2022, Infection Prevention (IP) investigated eight Klebsiella pneumoniae carbapenemase (KPC)-producing Citrobacter freundii cases identified at five facilities in a healthcare system to determine relatedness.

Methods: Chart reviews were conducted by IP to determine common links. KPC-producing Citrobacter freundii isolates were sent to the Minnesota Department of Health for whole genome sequencing (WGS), including multilocus sequence typing (MLST). Rectal screening was conducted on patients with an overlapping stay on an inpatient unit with one of the six hospital-onset index cases. Sixty-four patients in five inpatient units at three facilities were screened. The screening swabs were tested for certain Gram-negative bacilli and carbapenemase genes using the Cepheid GeneXpert CarbaR assay.

Results: One screening test identified KPC-producing Citrobacter freundii and 63 were negative. The isolates for the index patient and the associated screened patient had different MLST profiles, indicating that these infections likely were not related. Additional chart review revealed that six patients had procedures performed in interventional radiology (IR) at Facility A in the month prior to KPC-Citrobacter isolation. Three of the six IR patients had the same MLST profile. Rounding in IR revealed several IP concerns: low hand hygiene compliance and biofilms on sink aerators and faucets. Environmental cultures identified six species of Gram-negative bacilli and one fungus. Citrobacter freundii was not isolated. Staff in IR were provided education on hand hygiene and disinfection of surfaces; sink aerators were replaced.

Conclusions: Although a definitive source was not identified, WGS results suggest that four cases are linked and may have come from similar sources. It is possible that transmission occurred via healthcare worker hands that may have been contaminated by a biofilm in a scrub sink or shared equipment IR. Following infection prevention interventions in IR, no additional patients with KPC-producing Citrobacter freundii have been identified in our facilities.