Lab Matters Summer 2019 - Page 71

APHL 2019 POSTER ABSTRACTS We describe a real-time PCR assay that is accurate, sensitive, specific, and reproducible. We will implement this assay in parallel with culture-based colonization testing for 4 months, and will use the parallel testing data to inform the best testing algorithm for C. auris colonization screening. 1 Leach L, Zhu Y, Chaturvedi, S. Development and Validation of a Real-Time PCR Assay for Rapid Detection of Candida auris from Surveillance Samples. J Clin Microbiol. 2018;56(2). Presenter: Allen Bateman, Wisconsin State Laboratory of Hygiene, Madison, WI, allen.bateman@slh.wisc.edu Carbapenem-Resistant Acinetobacter baumannii Harboring a Plasmid Carrying blaOXA-72 in an Outbreak Involving an Intensive Care Unit and Long-Term Care Facilities in Wisconsin K. Florek 1 , S. Wagner 1 , M. Lasure 2 , N. Shrivastwa 2 , A. Bateman 1 , D. Warshauer 1 ; 1 Wisconsin State Laboratory of Hygiene, 2 Wisconsin Division of Public Health Background: Acinetobacter baumannii is an opportunistic pathogen implicated in a variety of healthcare-associated infections and is a concern in intensive care units. Here we report an outbreak during October 2018 involving patients in an intensive care unit (Facility A) in Wisconsin. Initially, Acinetobacter baumannii isolates with matching antimicrobial susceptibility (AST) profiles were identified in 5 patients in Facility A, suggesting the potential spread of a carbapenem resistant Acintobacter baumannii (CRAB). Methods: AST information was collected from three major clinical laboratories in the Wisconsin Clinical Laboratory Network on recent CRAB isolate submissions. An additional 3 isolates from Facility A and 1 isolate from Facility B were found to match the AST profile of the original 5 from Facility A. Isolates were submitted to the Wisconsin State Laboratory of Hygiene where sequencing was performed using both the Illumina MiSeq and the Oxford Nanopore MinIon sequencing platforms. To identify if the resistance mechanism was plasmid-borne, genome assemblies were created using a short read and long read hybrid assembly method. Results: Comparison of the 9 isolates by core genome and single nucleotide polymorphisms (SNPs) indicated that 6 of the 9 isolates were closely related, one of which was from Facility B. All six isolates contained a 10,879 bp plasmid carrying two copies of the OXA- 24/40-like β-lactamase OXA-72. All 6 plasmids were identical at the nucleotide level, while one isolate had a 5,845 bp region that was reversed and flanked with XerC/XerD-like recombination sites. These plasmids were only 3 SNPs different from a previously published CRAB plasmid pAB120 (JX069966). Conclusion: The combination of an established clinical laboratory network and strong laboratory and epidemiology communication helped identify a potential transmission route of this outbreak. These data helped identify a long-term care facility in Wisconsin (Facility C) as the connecting factor between Facility A and Facility B. Here we demonstrate the value in using AST as a method of prioritizing the use of valuable whole genome sequencing (WGS) resources on potential outbreak isolates. The combination of long read and short read WGS proved useful in the confirmation of outbreak isolates and identification of a plasmid-borne OXA-72. Assessing the Impact of the FDA Reclassification of Rapid Antigen Influenza Diagnostic Tests (RIDT) in Wisconsin E. Reisdorf, A. Bateman, M. Wedig and P. Shult, Wisconsin State Laboratory of Hygiene Background: In February 2017, a Food and Drug Administration (FDA) final rule reclassifying RIDTs from class I to class II devices with special controls to help improve the overall quality of testing for influenza virus went into effect. We assessed the early impact of the FDA reclassification on RIDT testing behavior and performance in Wisconsin. Methods: The Wisconsin State Laboratory of Hygiene (WSLH) collects detailed clinical laboratory testing information along with specimens submitted for respiratory pathogen surveillance from sentinel sites. This includes the diagnostic testing kit used and test results which are recorded in the laboratory information system. All surveillance specimens received are tested for influenza by real- time reverse transcription PCR (RT-PCR) (CDC Human Influenza Virus Real-time RT-PCR Panel (IVD)). The WSLH RT-PCR results were compared to those provided by the clinical laboratories to assess the “real world” performance characteristics at multiple clinical laboratories pre and post FDA reclassification. Data analysis was performed from the 2012-2013 to the current 2018-2019 influenza season. Performance of the RIDTs was assessed by determining the percent discordant rates obtained with RT-PCR testing at the WSLH. Results: Since the FDA reclassification, the number of different RIDT tests used by clinical labs in Wisconsin has declined from 8 during the 2015-2016 influenza season to 2 predominate tests (Quidel® Sofia and BD VeritorTM) in 2018-2019 season. The number of RIDTs reported were similar from season to season; however there has been an increase in the number of rapid molecular tests performed. The number of pre-screened RIDT surveillance specimens tested at WSLH ranged from 220 to 1,120. The percent discordant rates for all RIDTs specimens tested for the 2015-2016, 2016-2017, 2017- 2018 and 2018-2019 seasons were 11.8%, 8.8%, 10.3% and 10% respectively. The discordant rates before the reclassification ranged from 0% to 17.5% for those tests with >5 specimens tested by RT-PCR at the WSLH. After reclassification, the percent discordant ranges were 9.4% to 11.5% for the two RIDTs. Surprisingly, the influenza test with the highest discordant rate for the 2016-2017, 2017-2018 and 2018-2019 seasons was not an immunoassay RIDT, but a rapid molecular test. Conclusions: The FDA reclassification of the RIDTs from class I to class II devices may have had an impact by decreasing the number of tests that were used by clinical laboratories in Wisconsin to two. However, the overall performance of the RIDTs assessed by the percent discordant rates compared with RT-PCR testing at WSLH remained similar over the four influenza seasons that were analyzed (pre and post reclassification). The diagnostic influenza test with the highest discordant rate from the past three influenza seasons was a rapid molecular assay which was not subject to the FDA reclassification. Presenter: Erik Reisdorf, Wisconsin State Laboratory of Hygiene, Madison, WI, erik.reisdorf@slh.wisc.edu Presenter: Kelsey Florek, AR Fellow, Wisconsin State Laboratory of Hygiene, Madison, WI, kelsey.florek@slh.wisc.edu PublicHealthLabs @APHL APHL.org Summer 2019 LAB MATTERS 69