Antisera QC and IQCP and Associated Challenges

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1 Antisera QC and IQCP and Associated Challenges Patti Fields Enteric Diseases Laboratory Branch (EDLB) CDC 2017 APHL Annual Meeting Providence, Rhode Island June 14, 2017 National Center for Emerging and Zoonotic Infectious Diseases Division of Foodborne, Waterborne, and Enviromental Diseases

2 Thank you! Patti Fields The findingsand conclusions in this report are those of the author and do not necessarily represent the official position of the Centers for Disease Control and Prevention. For more information please contact Centers for Disease Control and Prevention 1600 Clifton Road NE, Atlanta, GA Telephone, CDC-INFO ( )/TTY: Web: National Center for Emerging and Zoonotic Infectious Diseases Division of Foodborne, Waterborne, and Environmental Diseases

3 Background: Serotyping Serotyping is a subtyping method Characterization of strains based on immunologic reactivit y of surface structures, commonly: Lipopolysaccharide (O antigen) Flagellin protein (H antigen) In Salmonella, it isa bit more complicated than other enteric organisms because: Includes species and subspecies identification because isolates of different subspecies can have the same O and H antigens Most Enterobacteriaceae have only one H antigen; Salmonella commonly has two different H antigens serotypes have been described (and counting)

4 Methods for serotyping Phenotypic methods Detect/differentiate expressed antigens using antibodies Hyper-immune rabbit antisera or monoclonal antibodies Can be a challenged to maintain antisera required 250+ reagents needed for all Salmonella serotypes 180 O groups described for E. coli Genetic methods Target genes responsible for serotype: rfb re g ion, flic, fljb Bonus: Replicates the phenotypic serotyping scheme Target surrogate markers, e.g., MLST Drawback: Can t type things you ve never seen before Variety of methods can be used: PCR, PCR-probe, WGS CDC plans to maintain phenotypic serotyping Reference Center for Traditional Microbiological Methods

5 Why is serotyping important? Why do we want to keep it? An international language The US has 50+ years of Salmonella surveillance data based on serot ype Many serotypes have unique niches and/or epidemiology Many do not (or has not been described) No longer the definitive subtyping method We now have genetic subtyping methods that provide a LOT more discrimination than serotyping can Some of the antigenic detail in Kauffmann-White Scheme no longer necessary Can we simplify the serotyping scheme?

6 Salmonella Serotyping Reagents Many specificities are available from CDC free-of-charge for the purpose of national surveillance CDC had funding to replenish antisera supply in late 1990s- early 2000s APHL was a huge partner. Thanks! Contracted with the state of California to produce more that 150 regents A 10 year supply has lasted 15+ years, but some specificities are running out

7 Salmonella Serotyping Reagents Expiration dates QC CDC reagents: re-evaluate RTD and extend expiration dates when needed Antisera QC under CLIA Reagents need to be QC d every 6 months Not a problem for commonly used reagents QC performed when working dilution is made, used up within 6 months What about rarely used reagents? QC at time of use (a LOT of work) Another solution: IQCP

8 What is IQCP? Individualized Quality Control Plan The alternative CLIA quality control (QC) option. Provides for equivalent quality testing to meet the CLIA regulations for non-waived t est s. Considers the entire testing process: pre-analytic, analytic and post analytic Consider the risks in each of these phases and applicable regulatory requirements Develop a plan to mitigate risks

9 CDC s approach to IQCP for serotyping CDC QMS team led us through the process Developed one IQCP for all serotyping we do: Quality control plan for phenotypic determination of serotype in Campylobacter, Escherichia coli, Salmonella, Shigella, Vibrio cholerae, an d Yersinia enterocolitica Basic organization Purpose and scope Overview of workflow List of risks QC plan to address risks QA p lan Supporting documentation

10 Flow chart

11 Risks (1 of 3 pages)

12 QC Plan

13 Supporting documentation for 5-year QC interval for antisera QC records for: 155 Salmonella reagents (thanks PHLs!) 20 E. coli reagents 5-20 reagents for each of the other organisms

14 Stability of E. coli O and H antisera Antisera produced between 1981 and 1991 No change in RTD in years (and counting )

15 Stability of Salmonella serotyping reagents Summary by reagent type Category # reagents # years lasted, range Reagents that failed QC 3 Reagents that never failed QC (yet) Monoclonal antibody reagents, H antigens Monoclonal antibody reagents, O antigens Absorbed rabbit antiserum reagents, H antigens Rabbit antiserum reagents, H antigens Rabbit antiserum reagents, O antigens Rabbit antiserum reagents, Vi antigen Total % of reagents that never failed QC (yet) 98.1% Did not track when a lot was depleted Summary by number of years reagent lasted # years lasted # reagents % of reagents % % % % % > % Total % Shorter # years lasted could be due to missing QC records or a lot being depleted Oldest Salmonella reagent on inventory is 36 years old Reagents made by the state of California are 13 to 20 years old (or depleted).

16 Reagent Salmonella serotyping reagents that Year of Manufacture Year of last QC pass failed # years lasted before failure What happened? Ha, rabbit antisera H2, absorbed rabbit antisera O10, mouse monoclonal antibody na na 4/2009: CDC was alerted by a SHD that the reagent failed their QC. Result confirmed at CDC the next day. Lot removed from inventory and other states notified via Enteric Bacteriology Listserv. 12/2006: Routine testing at CDC indicated titer had fallen and cross reactions seen at revised RTD. Lot removed from inventory and states notified via Enteric Bacteriology Listserv. 8/2010: Reagent failed QC while testing bulk in advance of dispensing. Reagent is a blend of two monoclonal antibodies and it appears one died.

17 CDC is happy to assist in any way we can with QC and QA issues CDC Enteric Bacteriology Discussion List Contact Blake Dinsmore at f t b 4@cd c.g o v if you would like to be added to the list. Salmonella Lab Inbox Salmonella@cdc.gov Reference Team Inbox entericreferencelab@cdc.gov Patti Fields pif1@cdc.gov

18 Thank you! Patti Fields The findingsand conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. For more information please contact Centers for Disease Control and Prevention 1600 Clifton Road NE, Atlanta, GA Telephone, CDC-INFO ( )/TTY: Web: National Center for Emerging and Zoonotic Infectious Diseases Division of Foodborne, Waterborne, and Environmental Diseases

19 Salmonella Serotyping Reagents CDC Inventory Category Reagent Status Solution H monospecific 2 out of stock H monospecific 7 out of stock H monospecific v out of stock H monospecific z24 out of stock H monospecific z28 out of stock O grouping 28 out of stock O monospecific 7 low bulk available for dispensing O monospecific 8 low bulk available for dispensing O monospecific 9 low H typing y low bulk available for dispensing H monospecific z51 low