APHL 2018 Annual Meeting Poster Abstracts
Presenter : Maureen Diaz , MPH , PhD , Centers for Disease Control and Prevention , Atlanta , GA , Phone : 773.329.5803 , Email : iqs5 @ cdc . gov
Evaluating the Flocked Swab as a Tool to Sample and Recover Healthcare Pathogens from Nitrile Gloves
H . Houston 1 , L . Rose 1 , J . C . Whitworth 1 , J . K . Johnson 2 , G . Robinson 2 , S . Leekha 2 , J . Noble-Wang 1 ; 1 Centers for Disease Control and Prevention , Atlanta , GA , 2 University of Maryland School of Medicine , Baltimore , MD
Flocked swabs are commonly used in healthcare for collecting clinical specimens for diagnosis and surveillance purposes . Manufacturers claim their charged fibers hold and release organisms efficiently , with some claiming superior performance for environmental sampling as well . In working toward developing a standardized , efficient hand and glove sampling and recovery method , we compared the use of a representative nylon flocked swab ( eSwab™ , Copan Diagnostics , Inc .) to a cellulose sponge , the Sponge Stick ( 3M™ ), as potential glove sampling devices . Nitrile gloves were inoculated with a carbapenem-resistant Klebsiella pneumoniae ( KPC ), methicillin-resistant Staphylococcus aureus ( MRSA ) and Clostridium difficile spores ( CD ) suspended in Artificial Test Soil ( Healthmark Industries , Inc .) to simulate body fluids . Inocula ( 50 µ l of 104 CFU / mL or 103 CFU / mL for vegetative cells and 105 CFU / mL or 104 CFU / mL for the CD spores ) were spread along each of the four fingers and across the top of the palm and allowed to dry for 10 minutes , then sampled with one flocked swab , two flocked swabs , or a Sponge-Stick ( SS ). Sampling devices were processed , eluents cultured , then enumerated and the percent recovery determined . We saw no significant difference between using one or two swabs to sample a single glove ( p > 0.05 ). The SS performed significantly better than flocked swabs when recovering CD ( SS 48.4 %, eSwab 18.3 %; p = 0.05 ) and KPC using a 104 inoculum ( SS 4.5 %, eSwab 1.6 %; p = 0.05 ). However , there was no significant difference between flocked swabs and SS when recovering MRSA and KPC using a 103 inoculum with the mean recoveries ranging between 8.1 % and 13.6 %. These results suggest that flocked swabs could be a useful and easy to use tool in sampling some organisms from gloved hands in the field as compared to other common sampling devices . Additional work is needed to evaluate multiple organic loads , glove types and additional organisms before a standardized method is developed . These data inform researchers , epidemiologists and infection control personnel as to options for sampling gloved hands in a healthcare setting .
Presenter : Hollis Houston , Centers for Disease Control and Prevention , Atlanta , GA , Email : vvk6 @ cdc . gov
Quality Assurance of Qualitative DNA Detection Assays for Long-term Surveillance Studies of Human Papillomavirus
T . Querec , C . Herbert , E . Kroll , K . Love , P . McKibben , J . Onyekwuluje , Y . Park , S . Patel , J . Pompey , M . Scarbrough and E . Unger , Centers for Disease Control and Prevention , Atlanta , GA
In 2006 , the US Food and Drug Administration approved the first human papillomavirus ( HPV ) vaccine . Since 2005 , the Chronic Viral Diseases Branch ( CVDB ) has tested for HPV genotypes in over 80,000 specimens to measure the impact of vaccination in
US surveillance studies . For reliable monitoring of trends , quality assurance of the assays is vital . CVDB uses multiple processes and controls to assure the performance of qualitative assays for detection of over 30 HPV genotypes . Fidelity of manually read line blot results is ensured by independent double reading and double database entry . Assays include probes for human ß-globin as an endogenous positive control and the frequency of inadequate samples ( HPV negative and ß-globin negative ) is monitored . Reference samples are run in parallel on current and new lots of kits to bridge lot-to-lot performance . Water blanks are processed with specimens as negative controls for cross-contamination . Positive HPV controls indicate a successful assay run . Ten percent of samples are re-assayed to determine reproducibility and when different types of assays are run on the same samples , assay concordance is determined . Laboratory personnel are trained and evaluated under a quality management system . Since 2007 participation in the WHO HPV LabNet Proficiency Studies has provided an independent assessment of assay performance . Assay results are reviewed quarterly in summary reports before data is submitted to partners . The quality assurance process has led to valuable insights and interventions . In a 2016 comparison between kit lots , the newer lot had weaker signal intensity and lower reproducibility than the current lot in use . Assay procedures were adjusted to maintain performance standards . Approximately 9 months later the vendor reported manufacturing issues . Nonconforming events with water negative controls contaminated with DNA have led to refinement of assay procedures , instrument maintenance and additional training of personnel . Quality assurance can also identify issues that originate outside the laboratory . In the first quarter of 2016 , the number of inadequate results for one study tripled from the previous 3 year trend from 6 % to 18 %. The issue was traced to one clinical collection site . The staff were retrained and the inadequate rate returned to baseline . Quality assurance helps to ensure the reliability of HPV genotyping results to measure the impact of vaccination . Future directions include consolidating assay results of different studies into a single relational SQL database and automating summary report creation to track more nuanced data trends and for more frequent monitoring reports .
Presenter : Troy Querec , PhD , Centers for Disease Control and Prevention , Atlanta , GA , Phone : 404.639.2864 , Email : hep0 @ cdc . gov
Genomic Sequence Analysis of Common Legionella pneumophila Sequence Types Recovered from Healthcare Facilities
B . Raphael 1 , J . Smith 1 , L . Cooley 1 , S . Roberts 2 , E . Brown 1 , L . Lie 2 , M . Ishaq 2 , J . Winchell 1 ; 1 Centers for Disease Control and Prevention , Atlanta , GA , 2 IHRC , Inc ., Atlanta , GA
BEST POSTER 2018
Hospitals and long-term care facilities may contain large , complex water systems which can become colonized with Legionella leading to cases of healthcare-associated Legionnaires ’ disease ( LD ). Individuals in healthcare facilities often have underlying conditions making them more susceptible to LD . The case fatality rate for healthcare-associated LD is approximately 25 %. During outbreak investigations of LD , isolates recovered from clinical specimens and environmental water samples can be analyzed with whole genome MLST ( wgMLST ) to characterize their genetic relatedness . Detection
Infectious Disease
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Summer 2018 LAB MATTERS 63 |