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PulseNet USA:. The National Molecular Subtyping Network for. Foodborne Disease Surveillance. Jennifer A. Kincaid. Centers for Disease Control and Prevention May 30, 2008. What is PulseNet USA?.
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PulseNet USA: The National Molecular Subtyping Network for Foodborne Disease Surveillance Jennifer A. Kincaid Centers for Disease Control and Prevention May 30, 2008
What is PulseNet USA? Establishedin1996,TheNationalMolecular Subtyping Network for Foodborne Disease Surveillance Nationalnetworkofstateandlocalpublic health/food regulatory agency laboratories (USDA, FDA) coordinated by CDC and APHL Performstandardizedmoleculartypingof foodborne disease-causing bacteria by Pulsed-field gel electrophoresis (PFGE) DynamicdatabasesofDNA “fingerprints”at CDC—available on-demand to participants
The National Molecular Subtyping Network for Foodborne Disease Surveillance USDA-APHIS New York Ag. Lab NEW HAMPSHIRE Milwaukee MAINE FDA-ORA VERMONT MI State WASHINGTON MINNESOTA MONTANA NORTH DAKOTA Vet Lab MASSACHUSETTS Philadelphia Ohio Ag. Lab OREGON WISCONSIN RHODE ISLAND NEW YORK CONNECTICUT IDAHO SOUTH DAKOTA FDA-ORA WYOMING New York City IOWA NEW JERSEY OHIO FDA-CVM NEBRASKA NEVADA DELAWARE ILLINOIS FDA-CFSAN UTAH FDA-ORA MARYLAND Washington D.C. FDA-ORA COLORADO VIRGINIA Las KANSAS Vegas KENTUCKY Santa Clara CALIFORNIA MISSOURI County USDA-AMS TENNESSEE SOUTH ARKANSAS OKLAHOMA FDA-ORA ARIZONA CAROLINA NEW MEXICO Los Angeles County USDA- FDA-ORA ARS/FSIS/FERN ALABAMA Orange County GEORGIA FDA-ORA Area Laboratories San Diego TEXAS LOUISIANA County PulseNet Headquarters Florida Ag. Lab ALASKA State/County/City/ Veterinary/ Agricultural Tarrant County Dallas County Laboratories Tampa Houston USDA Laboratories PUERTO RICO HAWAII FDA Laboratories West Mountain South Central North Central Midwest Mid-Atlantic Southeast Northeast
PulseNet Objectives To detectfoodbornediseasescaseclustersthatmay be widespread outbreaks Assistepidemiologistsininvestigatingoutbreaks Separateoutbreak-associatedcasesfromothersporadic cases (case definition) Assistinrapidlyidentifyingthesourceofoutbreaks (culture confirmation) Actasarapidandeffectivemeansof communication between public health laboratories (rapid alert system) Attributionanalyses
PulseNet: Communication and QA/QC On-linedatabases Standardizedprotocols CDCTeampostings and molecular size standards Clusterdetection Outbreakinvestigations QA/QCManual Technicalsupport Standardizedsoftware Quarterly/AnnualReports and nomenclature from CDC Trainingworkshops(lab “PulseNetNews”Newsletter & software) Tri-annualpublication Certificationand PulseNetWebsite (www.cdc.gov/pulsenet) proficiency testing Annualupdatemeetings
The Three Basic Elements of PulseNet 2.Dataanalysis 1.Dataacquisition 3.Dataexchange
Pulsed Field Gel Electrophoresis PFGE highly discriminatory Universal, relatively simple technique that can be used in most laboratories Definitive subtyping method, if highly standardized Current “Gold Standard” for molecular subtyping
PFGE Process Bacterial Suspension Mix with Agarose Plug Mold Chemical Lysis and Washing DNA in Plugs Restriction Enzymes Electrophoresis (PFGE) Documentation (capture gel image) Data Analysis (BioNumerics)
PFGE Patterns of E. coli O157:H7 Fragment * * * Sizes (in kilobases) 1135 Kb 452.7 Kb 216.9 Kb 76.8 Kb 33.3 Kb DNA “fingerprints” *Global Reference Standard
PulseNet Laboratory Network PulseNet National PFGE Patterns & Participating Labs Databases (CDC) Demographic Data TAT from receipt to upload: ~4 working days D base Management Local Reports Databases
Local vs. National Databases Local National Smaller,resultsfromafew Larger,resultsfrommany people different labs Smallerrepresentationof Largerrepresentationof patterns patterns Tendstobelessdiverse Morediverse Sometimesdifferent Different “common”patterns “common” patterns than seen than seen locally nationally or in other regions Seerepresentationfromall Canonlyseelocal over, different regions representation, no national perspective
PulseNet Activity* *as of May 15, 2008 Over 325,000 PFGE patterns or DNA “fingerprints” submitted to PulseNet databases since 1996 Database Entries Patterns submitted Submitted 1st Enzyme 2nd Enzyme Campylobacter 5,453 5,400 1,834 E. coli 31,634 30,262 16,674 Listeria 9,226 9,007 8,002 Salmonella 190,298 188,241 28,998 Shigella 32,922 32,222 2,156 V. cholerae 303 282 272 V. parahaemolyticus 37 37 37 Y. pestis 1,976 1,975 33
PulseNet Activity, 1996-2007 PFGE patterns submitted to PulseNet Databases 70000 60000 50000 40000 30000 20000 10000 0 1996 1997 1998 1999 2000 2001* 2002 2003 2004 2005 2006 2007
PulseNet is a cluster detection tool, not an outbreak detection system A PulseNetCLUSTERisagroupof patterns that are found indistinguishable by PFGE CLUSTERSofcasesidentifiedby PulseNet are investigated by epidemiologists Ifepidemiologiclinksarefoundbetween cases, the cluster is classified as an OUTBREAK
PulseNetDataAnalysis: The Cluster Search •Patterns submitted electronically • 60- or 120-day cluster search performed •Visually compare indistinguishable •Patterns and clusters are named by CDC •Clusters communicated to the foodborne epidemiologists Cluster of indistinguishable patterns
Cluster Detection in PulseNet: PulseNet Workspace on CDC Team Subject:0802LACJPX-1c (JPXX01.0088)_LAC_Typhimurium LAC has a cluster of 3 Typhimurium isolates that are indistinguisable by XbaI and BlnI. The collection dates are from 12/10/2007 to 1/10/2008. Epi under investigation. The isolate numbers are: LAC_Z19766 2 year old boy, no travel LAC_Z19999, 43 year old female, no travel LAC_Z20072, 60 year old female, no travel We have seen this pattern before in LAC. Our epi contact is (name and phone) LAC08008PN.BDL Posted: 05 March 2008 09:52 AM
Cluster Detection Local National Performclustersearch Performclustersearch within local database withinnationaldatabase or respond to local CDC Comparetonational Team posting database Verifyisolateinformation PostmessagetoCDC Namepatterns Team Checkbandmarkings Beginepiinvestigation Assignclustercode Lookatpattern frequencies/trends
A large outbreak in one place may be obvious Detected and investigated locally
A dispersed outbreak in many places may be difficult to detect, unless… Detect outbreaks centrally (or locally) through surveillance (widely dispersed, organism too common to notice small increase, identify related cases) Investigation coordinated centrally Distinguish from concurrent sporadic cases Provide microbiological evidence of sources of outbreaks
Common CDC Epi Requests Pasttrendsorpastassociationof cluster/outbreak pattern PatternFrequencygraphs PulseNetClusterLog Cluster/Outbreakcodes Updatedlinelists Oftendailyforveryactiveorhighprofileoutbreaks Additionalinformationforrumorlogsand conference calls
CDC Epi Requests: Additional Info Secondenzymeresults VetNetmatches USDA-ARSdatabase Connectionto VetNetnetworkestablishedin2007 Allclusterpatternsidentifiedby PulseNetareroutinelycheckedagainst VetNet Internationalmatches Connectionto PulseNetCanadadatabasesestablishedin2007 Allclusterpatternsidentifiedby PulseNetareroutinelycheckedagainst PulseNet Canada databases PulseNetparticipantsabroad(PulseNetLatinAmerica,Europe,Asia Pacific, and Middle East) Emailalertsto PulseNetInternational
Interpreting Patterns within Outbreaks Forsurveillance(clusterdetection),allowno differences for possible matches One-banddifferencesaresocommoninlargedatabases that virtually all submissions would be part of a cluster Foroutbreaks(casedefinition),differencesmaybe acceptable Maybenecessaryforshigellosisinfections(personto person) Iftheisolateswithdifferentpatternshaveepidemiologic links, assign different pattern names but include in reports (give same outbreak code)
Additional Restriction Enzymes Addstothediscriminationofallorganisms when using PulseNet protocols makesclusterdetectionmoreprecise Canlimittheneedforepifollow-upoflikely unrelated cases AlthoughitaddstothecostofPulseNet surveillance, running fingerprint profiles of both enzymes on the initial gel is often cost-effective and saves time
Additional Restriction Enzymes Example Salmonella Montevideo Indistinguishable 1st enzyme patterns: need 2nd enzyme results to distinguish clusters
E. Coli O157:H7 Outbreak in Colorado, July 2002 Outbreakpatternwasrare Closelyrelatedtoaverycommonpattern 34casesin11states Outbreakstrainfoundingroundbeeffrommeat processing plant by USDA/FSIS Outbreakstoppedafterrecallof18.4million pounds of ground beef products from a plant
1993 Western States E. coli O157 Outbreak 70 60 outbreak detected 1993 726 ill, 4 deaths 50 40 30 39 d 20 10 0 1 8 15 22 29 36 43 50 57 64 71 Day of Outbreak 2002 Colorado E. coli O157 Outbreak 70 60 50 outbreak detected 2002 44 ill, no deaths 40 30 20 18 d 10 0 1 8 15 22 29 36 43 50 57 64 71 Day of Outbreak
S. Tennessee outbreak numbers (April 11, 2007) 567cases 47statesinvolved Nointernationalcases Medianage51years(<1-95years) 73%females Nodeaths,20%hospitalized Amongfemales:1/3UTI
Salmonella Tennessee Cases by State, (N=563) 1-9 cases 10-19 cases 20+ cases *Slide courtesy of EIS officer Anandi Sheth
Peanut Butter Samples 34 positive samples of peanut butter Production dates from contaminated jars: 7/27/06 - 1/29/07 2 of the 3 outbreak patterns were found in the peanut butter
Notable Outbreaks SalmonellaWandsworthand Typhimurium: Veggie Booty SalmonellaHeidelberg:Hummus SalmonellaI4,5,12:i:-:Potpies SalmonellaEnteritidis:ChickenCordonBleu E.coliO157:groundbeef E.coliO157:frozenpepperonipizza Listeriamonocytogenes:milk
Database Uses: Pattern Frequencies Long-term surveillance to aide in active surveillance—is this a true increase?
Database Uses: Pattern Trends Long-term surveillance to see if a pattern is still seen as commonly in the database
Database Uses: Attribution Analysis Long-term surveillance to see if certain patterns may be associated with specific foods Legend CDS 1 CDS 2 CDS 3 CDS 4 CDS 5
PulseNet S. Newport Attribution Analysis Figure 13: Proportional Distribution of Illnesses by food commodities using three attribution analysis methods 30.0% 25.0% 20.0% Method 1 15.0% Method 2 Method 3 10.0% 5.0% 0.0% Food Commodities Method 1: Considering three major clusters Method 2: Considering major clusters and sub-clusters Method 3: Considering sub-clusters with no non-human isolates of unknown
PulseNet International… A Family of Networks
Why are we going international with PulseNet? Weliveinaglobalcommunity Foodsproducedononecontinentmaybe consumed and cause disease in another - a global issue Needaneffectiveglobalearlywarningsystem Globalnetworkingtoutilizescarcepublichealth resources effectively Respondtootheremerginginfectiousdiseasesor acts of bioterrorism
PulseNet International Collaborations Outbreakinvestigations LaboratoryandAnalysisTroubleshooting Protocoldevelopmentandvalidation Vibriocholerae Vibrioparahaemolyticus Development,EvaluationandValidationof Next Generation Typing Methods Canada,China,HongKong,JapanandU.K.MLVA subtypingprotocolfor E.coliO157
PulseNet Challenges and Future Improvements Enhancesupportforoutbreakinvestigations Newfastermethods Reducethetimeittakesforisolatestogofrom clinical lab to the state/local public health lab ReducethetimeforPFGEtestingofisolates Expectation:~4daysfromreceiptofisolatetouploadto the national database(s) Achievereal-timedetectionofclusters Improvecommunicationbetweenlaboratoriansand epidemiologists at the state and national levels
PulseNet Challenges and Future Improvements Strengthencollaborationswithfoodindustry VetNet(USDA-ARS) Currentlycollecting Salmonellaand CampylobacterNARMS isolates Attributionanalysis Protocols Vibrioparahaemolyticus Protocolhasbeendevelopedanddatabasescriptswere included in the latest version of the MasterScripts (March 2007) Thenumberofsubmissionsto PulseNet continues to rise…..
New Subtyping Methods PFGEdataiscomplex Needforsimple,non-imagebasedas discriminatory supplementary methods Sequencingbasedmethods Multi Locus Variablenumberoftandemrepeats Analysis(MLVA) SNPanalysis
MLVA Analysis Sequence-basedsubtyping CanfurtherdiscriminatecommonPFGE patterns through highly variable target sequences Datamaybeepidemiologicallymorerelevant than PFGE data Resultsmorestraightforward Don’thavethesameinterpretationissuesaswith PFGE band marking
Thank you for your attention The findings and conclusions in this presentation are those of the author and do not necessarily represent the views of the Centers for Disease Control and Prevention.