505. Making of a “Super-Duper Bug”: Plasmid-Mediated Resistance Accumulation in a Carbapenemase-Producing Klebsiella quasipneumoniae from Patients and the Environment

BACKGROUND: Carbapenemase-producing Enterobacteriaceae can form a reservoir in hospital wastewater biofilms. Klebsiella quasipneumoniae is increasingly recognized as an emerging nosocomial threat, frequently carrying antimicrobial resistance (AMR) genes on plasmids. The dynamics of AMR gene and plasmid gain/loss over time in this species remain unclear. METHODS: Klebsiella pneumoniae carbapenemase producing-K. quasipneumoniae (KPC-Kq) isolates from patients and wastewater sites from drains and toilets were sequenced (Illumina). Sequence assemblies (SPAdes) were probed in silico for AMR genes and plasmid Incompatibility types (using AMRFinder and PlasmidFinder databases, respectively). For related isolates (<100 SNV) cultured from the same sites longitudinally, we compared the accumulation of AMR genes in patients and environmental reservoirs over time. RESULTS: From 2009 to 2016 there were a total of 15 KPC-Kq isolates from 8 patients and 17 environmental isolates from 11 rooms. The mean number of resistance genes identified in patients and environmental isolates were 15 and 14, respectively (P = NS), with five resistance genes carried by all isolates including bla(KPC). There was an average of 4.4 unique incompatibility types from patients and 4.0 from the environment (P = NS). For the longitudinal subset, there were 17 related isolates from two patients and two sink drains. One hospitalized patient with repeated antimicrobial exposure had a KPC-Kq initial isolate with 3 plasmid types and 13 AMR genes and died one year later with a KPC-Kq isolated from blood with 11 plasmid types and 25 AMR genes. The other patient was primarily an outpatient with little antimicrobial exposure. His KPC-Kq lost 1 plasmid and 3 AMR genes over 15 months. One KPC-Kq strain in the environment lost 3 plasmid types and 8 AMR genes over 4 months; the other was unchanged over 5 months. CONCLUSION: KPC-Kq has been seen in both patients and the environment for several years at our institution. Sequencing of longitudinal isolates revealed that under antimicrobial pressure a patient KPC-Kq accumulated multiple plasmids and AMR genes. This same accumulation was not witnessed environmental sites over time although the numbers are small and will require confirmatory work. DISCLOSURES: All authors: No reported disclosures.