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Enhancing Legionella Testing Capacity for Clinical and Environmental Samples at
the Washington State PHLJeff Lahti
Lead MicrobiologistWashington State Department of Health
• Pre 2017 testing capabilities in Washington
• Our thought process on which tests to implement
• A brief look at the tests that were implemented
• A look at our future plans
• Helpful validation ideas
Outline
Legionnaires’ Disease Cases Reported to WA DOH by Year of Onset
0
10
20
30
40
50
60
70
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
Case
Cou
nt
Year of Onset
Case counts are on an increasing trend nationally as well
Legionella Testing in Washington• Most hospitals do not collect a respiratory specimen, instead
rely on the urine antigen test
• There were only few facilities that maintained the capacity to culture a clinical specimen
• There were only 2 facilities that participated in the ELITE program
• If a large outbreak occurred, the state lab had no procedures for culturing clinical or environmental samples
– We are working to revise the WAC to state “isolates or the respiratory specimen associated with a positive result be submitted to the state”
What capabilities were needed
– Culture
– Increase sensitivity and turn-around-time of samples using a molecular assay
• After examining what the state lab can offer, we identified the areas that needed improvement
– Rapid identification of isolates
– Training for microbiologist to identify and isolate Legionella from specimens
Where to Start
– We had a microbiologist with experience Legionella isolates
• We decided to concentrate on enhancing clinical testing first
– In clinical micro a procedure existed for identification of isolates
– We still had unresolved issues regarding testing in our environmental lab, i.e. incubators, BSC, filtering equipment
– Clinical testing was considered “easier” to implement since there were more resources available
Isolate Identification
• First step was to expand identification capabilities
• Microgen Latex Kit
• Easy to use
• Rapid identification
• Added the ability to identify L. pneumophila SG1
• This kit can be used for clinical and environmental isolates
Photo curtesy of Microgen Bioproducts https://microgenbioproducts.com
Add Selective Media
• Next we expanded our media to include BCYE-PAV and BCYE-GPVC– We chose to add these two antibiotic plates since they were
cited the most for use in clinical and environmental isolation
• BCYE-PAC was also evaluated…– BCYE-PAC worked great for pneumophila,
but very poor with other species. – 6/9 species didn’t grow – 4/9 species had poor recovery
Validate Culture and PCR• Last step was to validate the culture and PCR• These validations were done at the same time
– Material was limited– The matrix was spiked– Had one dedicated microbiologist working on the
validation– Able to dedicate a BSC and ABI 7500 FAST
Future Testing
• WGS
• MALDI-TOF
• Legiolert
Helpful Validation Hints• Secure the testing material early on
– Isolates– Matrix
• Write a very detailed validation plan
• Risk Assessment
• Have one person in charge of the validation. They write the plan, oversee the testing and present the data for approval
Helpful Validation Hints• Create a flow diagram of the validation plan
Helpful Validation Hints
• Dedicate lab space for the validation
• Seek out training opportunities– CDC– Old ELITE PT
References
CDC’s ELITE programwwwn.cdc.gov/ELITE/public/elitehome.aspx
Garcia, Lynne Shore; Isenberg, Henry D. “Legionella Cultures 3.11.4” Clinical Microbiology Procedures Handbook 3rd ed., Lynne S. Garcia. 2007. Washington D.C.: ASM, c2010.
ISO 11731:2017 Water quality – Enumeration of Legionella
Jorgensen, Hames H, Pfaller, Michael A, Carroll, Karen C. Manual of Clinical Microbiology 11th ed. Washington D.C : ASM, 2015 887-904
References“Legionella (Legionnaires' Disease and Pontiac Fever).” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 30 Apr. 2018, www.cdc.gov/legionella/labs/procedures-manual.html
Rice, E.W., Baird, R.B., Eaton, L.S., Clesceri. Standard Methods for the Examination of Water and Wastewater. 20th ed. 1998. Washington, DC: American Public Health Association, 2012. Print.