604. Gram-Negative Bacilli Carrying Multiple Carbapenemases: the United States, 2012–2018

Abstract Background Gram-negative bacilli carrying multiple carbapenemase genes (multi-CP-GNB) present an emerging public health threat; to date, most isolates reported in the literature have been from outside the United States. We reviewed multi-CP-GNB reported to CDC. Methods Reports of multi-CP-GNB isolates carrying genes encoding >1 targeted carbapenemases (i.e., KPC, NDM, OXA-48-type, VIM, or IMP) were received from healthcare facilities, health departments, and public health laboratories, and included isolates tested through the AR Laboratory Network (ARLN) beginning in 2017 as well as isolates sent to CDC for reference testing. Epidemiologic data were gathered by health departments during public health investigations. Results From October 2012 to November 2018, 111 multi-CP-GNB isolates from 71 patients in 20 states were identified. Two patients had three different multi-CP-GNB and one patient had two different multi-CP-GNB. The majority of cases (76%) were reported in 2017 or later, after ARLN testing began. Among patients with multi-CP-GNB, the most common organism-mechanisms combination was Klebsiella pneumoniae carrying NDM and OXA-48-type enzymes (table). Urine (44%) and rectal (20%) were the most frequent specimen sources for isolates. The median age of patients was 63 years (range 2–89 years); most had specimens collected at acute care hospitals (87%) or post-acute care facilities (9%). Of 50 patients with information available, 37 traveled internationally in the 12 months prior to culture collection. Among these, 88% were hospitalized for ≥1 night while outside the United States with 10 countries reported, of which India was most common (n = 18). All 5 patients with Pseudomonas aeruginosa co-carrying carbapenemases reported recent hospitalization outside the United States. Conclusion The multi-CP-GNB reported to CDC include diverse organisms and carbapenemase combinations and often harbored carbapenemases from different β-lactamase classes, which may severely limit treatment options. Healthcare exposures outside the United States were common; providers should ask about this exposure at healthcare admission and, when present, institute interventions to stop transmission in order to slow further US emergence. Disclosures All authors: No reported disclosures.