837. Contamination of Hospital Drains by Carbapenemase-Producing Enterobacterales (CPE) in Ontario, Canada

Background The hospital water environment is a CPE reservoir, and transmission of CPE from drains to patients is a risk. Methods We cultured sink and shower drains in patient rooms and communal shower rooms that were exposed to inpatients with CPE colonization/infection from October 2007 to December 2017 at 10 hospitals. We compared patient room drain CPE to prior room occupant CPE using Illumina and MinION whole-genome sequencing. Results Three-hundred and ten inpatients exposed 1,209 drains, of which 53 (4%) yielded 62 CPE isolates at 7 (70%) hospitals. Compared to room occupant CPE isolates, drain CPE isolates were more likely Enterobacter spp. (6, 10% vs. 25, 51%, p< 0.0001) or KPC-producers (9, 15% vs. 23, 47%, p=0.0002). Of the 49 CPE isolates in patient room drains, 4 (8%) were linked to a prior room occupant (Table), 24 (49%) had the same carbapenemase as a prior room occupant but isolates/carbapenemase gene-containing plasmids that were unrelated, and 21 (43%) did not share a carbapenemase with a prior room occupant. The 4 drains linked to prior room occupants were likely contaminated by these room occupants, who were CPE-colonized prior to drain exposure. Despite few links between drain and room occupant CPE, there were 10 isolates harbouring related blaNDM-1-containing IncHI2A/HI2-type plasmids in 8 rooms on two units at one hospital. Nine of these were Enterobacter hormaechei ST66 isolates that were 0 to 6 SNVs apart and one was a Klebsiella oxytoca STnovel isolate. Table. Four patient room drain CPE isolates (D1b, D4, D5, D12) and isolates from prior room occupants that they were related to by whole-genome sequencing. Conclusion It was uncommon for drain CPE to be linked to prior patient exposure. This suggests contamination of most drains by undetected colonized patients and a need for more aggressive patient screening in our hospitals. This may also suggest retrograde (drain-to-drain) transmission, especially considering the 10 isolate drain cluster at one hospital. Reasons for the preponderance of Enterobacter spp. in drains requires further study. Disclosures Allison McGeer, MD, FRCPC, GlaxoSmithKline (Advisor or Review Panel member, Research Grant or Support)Merck (Advisor or Review Panel member, Research Grant or Support)Pfizer (Research Grant or Support)