APHL 2022 POSTER ABSTRACTS
Infectious Diseases to version RUO 2.0 . While the Chromacode ® assay has potential for applications in vector surveillance , PHEL has currently decided to move forward with an in-house developed multiplex assay for pathogen screening in all species of ticks relevant to the state of New Jersey .
Presenter : James Occi , New Jersey Public Health and Environmental Laboratories , james . occi @ doh . nj . gov
A Public Health Laboratory Response to a Recent Legionnaires ’ Disease Outbreak
G Ohanian , J McConnell , C Wake , R Jaquez , I Rubinstein , J Novak , HY Chow , A Olsen , A Arroyo , M Chowdhury , J Wang , B Ndala , L Huang , K Fernandez and E Iuppa Burke , New York City Department of Health and Mental Hygiene Public Health Laboratory
In August 2021 , there was an outbreak of Legionnaires ’ disease with 18 confirmed cases in a Central Harlem neighborhood of New York City ( NYC ). At the start of the outbreak investigation , the Bureau of Communicable Disease ( BCD ) received a proximity analysis report and a SaTScan signal identifying a cluster of Legionella-positive patients residing in Harlem . Previous outbreaks of Legionnaires ’ disease in NYC were associated with cooling towers . Therefore , 19 cooling tower water samples were collected by the New York City Department of Health and Mental Hygiene ( DOHMH ) Bureau of Public Health Engineering ( PHE ). These samples were sent to DOHMH ’ s Public Health Laboratory ( PHL ) for detection and isolation of Legionella . Two isolates of Legionella pneumophila serogroup 1 ( Lp1 ) from affected patients were also obtained by PHL for potential source matching and confirmation . Using real time multiplex PCR , PHL found that 10 out of 19 water samples contained Legionella pneumophila DNA within 30 hours from time of collection . This rapid response allowed remedial actions to be taken , the first following the PCR results was to hyperhaloginate ( water associated with ) the positive sites . PCR positive cooling tower water samples were concurrently tested using ISO 11731:2017 ( E ) and Legiolert ( IDEXX , USA ) culture-based methods . The culture results subsequently triggered the issuing of Commissioner ’ s Orders to fully clean and disinfect the cooling towers found to have viable Legionella pneumophila present . Isolates recovered from environmental samples and patient specimens were subjected to pulsed field gel electrophoresis ( PFGE ) and whole genome single nucleotide polymorphism ( SNP ) analysis . PFGE and SNP based comparisons linked one patient with a cooling tower that was under investigation . The Lp1 strain isolated as the source of this outbreak was closely related to a reoccurring Lp1 strain that has been implicated in other Legionnaires ’ diseases outbreaks in New York City . This investigation and confirmatory laboratory testing by the PHL allowed the Health Department to rapidly identify a source of the Legionnaires ’ disease outbreak and effect remedial actions , preventing the further spread of disease .
Presenter : Greta Ohanian , New York City Public Health Laboratory , gohanian @ health . nyc . gov
Validation and Implementation of Real Time PCR for Rapid Identification of Candida auris from Clinical Surveillance Samples in a Local Public Health Laboratory Setting
L Mikhail and M Crumpler , Orange County Public Health Laboratory
Background : Candida auris is a worldwide emerging pathogen known for causing infections and outbreaks in health care settings . In Orange County , CA , C . auris has been circulating and causing outbreaks in long term care facilities since 2019 , with a case count of 1,017 from February 2019 to December 2021 . Starting October 2021 , additional surveillance samples were tested from new patient admissions and potential events / outbreaks in subacute units ( SAU ).
Objective : To evaluate a real-time PCR assay for rapid identification of C . auris from patient surveillance samples at the Orange County Public Health Laboratory .
Method : To achieve this goal , an extraction protocol using the MasterPure kit ( Biosearch Technologies ) and automated EZ1 Advanced XL ( Qiagen ) instrument followed by real-time PCR was conducted using PerfeCTa Multiplex qPCR TaqMan ( Quanta Biosciences ) and the 7500 Fast Dx ( Applied Biosystems ). The assay was initially evaluated using 131 previously tested and frozen / refrigerated patient surveillance samples as well as 123 prospective fresh surveillance samples collected from different body sites ( nares , axilla , groin , perirectal , fingers / hands and axilla / groin ).
Results : The assay was highly reproducible at a limit of detection of 230 CFU / ml . The analytical sensitivity and specificity of the assay was 100 % for both . The performance from the 131 previously tested / frozen samples was 90 % for analytical sensitivity and 86 % for analytical specificity . The clinical sensitivity and clinical specificity of the 123 prospective samples was 93 % and 90 % respectively . Based on receiver operating characteristic ( ROC ) curve analysis , a cycle threshold ( CT ) value of ≤ 36 as positive and > 36 as negative were reached for the previously tested samples . A revised ROC curve analysis was calculated for the prospective samples yielding a cutoff of ≤ 37 which was determined to be the ideal diagnostic value for patient surveillance samples .
Conclusion : The successful implementation of the real-time PCR assay for C . auris in a county public health laboratory setting allows for accurate and rapid screening and identification of C . auris and contributes to enhanced surveillance and control of C . auris spread in local health care facilities .
Presenter : Lydia Mikhail , Orange County Public Health Laboratory , lmikhail @ ochca . com
Clinical and Analytical Performance of the VITROS ® Immunodiagnostic Products HIV Combo Assay
P Contestable , L Colt , R Polimeni and C Noeson , Ortho Clinical Diagnostics
Background : This study was designed to assess the clinical and analytical performance of the VITROS Immunodiagnostic Products HIV Combo Assay ( VITROS HIV Combo Assay ) on the VITROS ® family of systems . The assay is capable of simultaneous detection of HIV antibodies ( Ab ) and HIV p24 antigen ( Ag ) to help enable earlier diagnosis of HIV infection .