553. Outbreak of Methicillin-Resistant Staphylococcus aureus Associated with Hepatic Artery Infusion Pumps

Abstract

Background. Device-related infections account for a fourth of all HAIs. Hepatic artery infusion pump (HAIP) devices are used to deliver chemotherapy directly into the hepatic artery. This device is used primarily in patients with colorectal cancer for the management of unresectable hepatic metastases. We describe the infection rates and outbreak management of MRSA-related infections in newly placed HAIPs. Methods. In December 2018, a cluster of 3 MRSA cases was identified within 15-26 days of HAIP insertion. From January 1, 2017 to December 31, 2018, patients with culture proven SSIs within 30 days of HAIP placement were identified through the infection control database to establish baseline rates. Procedural denominator data were found by querying CPT procedure codes. EMR was reviewed to extract clinical characteristics. In response to the cluster, healthcare personnel (HCP) were screened for MRSA by PCR and environmental cultures performed. PFGE and whole-genome sequencing (WGS) was performed to compare isolates recovered in culture and SNP analysis performed using the BioNumerics software v7.6. Results. IIn December 2018, 3/15 patients with HAIP procedures developed MRSA infections within 30 days of the procedures (post-op days: 15,16,26). The baseline 30 day SSI rate for HAIP in 2017 was 1.3% (2/160). No infections, prior to the cluster, in 2017-18 were MRSA related. All patients were male, with a median age of 49 years (range: 45-54). Sixty HCP who provided direct care during the peri and early post-operative period for the 3 cases were screened for MRSA carriage; 2/60 (3.3%) were positive. All 56 environmental cultures were negative for MRSA. WGS of the 3 patient samples showed 2/3 samples were identical (1 SNP difference); confirming common source transmission. Only one HCP isolate was available for WGS and shown to be unrelated to the two patient isolates. Both employees underwent decolonization. Review of HAIP handling did not reveal obvious lapses, but mask use and strict hand hygiene were enforced with HCPs. No further infections have been identified in the 76 procedures since the cluster. Conclusion. WGS confirmed common source transmission between two newly placed HAIP although the definitive source could not be identified. Surveillance and prevention efforts should extend to all types of vascular access devices.