Faculty Disclosure. Peter C. Iwen, PhD, D(ABMM) Dr. Iwen has listed no financial interest/arrangement that would be considered a conflict of interest.

Transcription

1 Faculty Disclosure Peter C. Iwen, PhD, D(ABMM) Dr. Iwen has listed no financial interest/arrangement that would be considered a conflict of interest.

2 Foodborne Disease Surveillance and Increased Salmonellosis: What in the World is Going On? Peter C. Iwen, PhD, D(ABMM) Nebraska Public Health Lab UNMC Omaha, NE

3 Outline Basic biology of Salmonella Foodborne disease surveillance Outbreak investigation Salmonella as a bioweapon? Concluding comments

4 Perspective Annual cases Mortality Salmonellosis 40,253 (06)? Seasonal influenza 39,827 (07-08) >3,000 Typhoid fever 413 (06)? H1N1 (New variant) 13,217 (6/4/09) 27

5 Basic Biology of Salmonella Taxonomy Clinical Laboratory diagnosis

6 Taxonomy Bacteria Gram-negative rod Name Salmonella Dr. D.E. Salmon 1885 US veterinary surgeon Bacteriologist True pathogen Not normal flora GNR, Gram stain, 1000x

7 Taxonomy Salmonella enterica Subspecies Subspecies I Subspecies II Subspecies IIIa Subspecies IIIb Subspecies IV Subspecies VI Serotypes subsp. enterica subsp. salamae subsp. arizonae subsp. diarizonae subsp. houtenae subsp. indica Over 2,600 ~1,600 in subsp. enterica (most human pathogens) Salmonella bongori Formerly Subsp V

8 Most Common Serotypes 2006 Typhimurium 6872 Enteritidis 6740 Newport 3373 Heidelberg 1495 Javiana 1433 Salmonella enterica serotype Typhimurium Typhi 413 (Typhoid fever) Paratyphi A and B 320 (Paratyphoid fever) Total 40,666 CDC, Salmonella Annual Summary, 2006

9 Clinical Information How do you catch Salmonella? Note: Salmonella are ubiquitous in animals Food borne Transmitted via improperly prepared contaminated food or water Reptiles Poultry

10 Clinical Information How does Salmonella affect the body? Gastroenteritis Most common foodborne infection Bacteremia Salmonella serotype Choleraesuis Enteric fever Salmonella serotype Typhi Disease collectively called salmonellosis

11 Laboratory Diagnosis Isolate pathogen Clinical material Food products Salmonella ID Serogroup Nebraska Public Health Laboratory Salmonella serotype ID Strain type DNA fingerprinting PFGE

12 Salmonella ID Routine laboratory identification Combination of: Biochemicals Serological tests 48 + hrs to ID serogroup Additional 72 + hrs to ID serotype Additional 48 + hrs to fingerprint

13 Isolation Stool specimen Selective medium MacConkey agar HE agar MAC HE Normal enteric flora Presumptive Salmonella

14 Salmonella ID Biochemical ID Pattern Commercial/manual Serological Latex agglutination test Major serogroups A, B, C1, C2, D1, E1 Vi antigen Presumptive for Salmonella ser Typhi

15 Serogroup ID Latex agglutination A Group O:2 B Group O:4 (includes Typhimurium and Saintpaul) C 1 Group O:7 C 2 Group O:8 (includes Newport) D 1 E1 Group O:9 Group O:3,10 (includes Enteritidis and Typhi)

16 Serotype ID Public health surveillance Limited to reference labs Antigenic properties of surface structures O antigen Somatic (cell wall) H antigen Flagellar Vi antigen Capsular polysaccharide Kauffmann-White Scheme WHO Pasteur Institute, Paris

17 Specific O-Antigen Multiple types Designated by number 1-67 Each serogroup Unique pattern of O antigens Part of antigenic formula 4,5,12:i:1,2 Salmonella serotype Typhimurium 9,12,[Vi]:d:- Salmonella serotype Typhi Detection method Use specific O group antisera Plate agglutination

18 Specific H-Antigen Isolate must be actively motile Flagellar antigen Multiple types Phase 1 and Phase 2 usually Expressed as lower case letter or # Only one phase expressed Phase reversal To detect the masked antigen Requires specific H-typing antiserum Antigenic formula 4,5,12:i:1,2 diphasic Salmonella serotype Typhimurium 9,12,[Vi]:d:- monophasic Salmonella serotype Typhi Detection method Motility testing Phase reversal with antisera Tube agglutination Motility Phase reversal Tube agglutination

19 Salmonella Serotype ID Serotype formula Identifies serotype Usually named Animal source/disease type Geographical location Over 2,600 recognized Typical format Name Salmonella enterica serotype Saintpaul Serotype formula I 4,5:e,h:2 Subspecies [space]o-antigens[colon]phase 1 H-antigen[colon]Phase 2 H-antigen

20 Foodborne Disease Surveillance

21 Foodborne Disease Surveillance Salmonellosis Nationally notifiable disease Multiple federal agencies CDC FDA USDA MMWR, 2008/Vol. 55

22 Foodborne Disease Surveillance Laboratory surveillance PulseNet program Public Health Labs DNA fingerprint

23 DNA Fingerprint Identifies related strains History PulseNet Program CDC and APHL Collaboration Network of laboratories Public Health Labs (NPHL) Food testing Began early 2000s Pulsed-field gel electrophoresis (PFGE) Molecular subtyping or fingerprinting Distinguish strains Escherichia coli O157:H7 Salmonella Shigella Listeria monocytogenes Campylobacter jejuni

24 How does PulseNet Work? Participant labs perform PFGE Isolates of interest PFGE patterns Uploaded to a national database Maintained by the CDC Data analyzed Database managers State level Federal level Look for clusters Indistinguishable Epidemiological investigation State epidemiologist Federal epidemiologist

25 CDC, public domain What is the PFGE process?

26 Processing Steps Remove DNA from Salmonella Cut DNA into segments Approximately 4,000,000 base pairs (4 mb) Restriction enzymes Insert cut DNA into a gel Electrophoresis Using a pulsed-current Stain pulsed gel Analyze data Restriction fragment pattern

27 PFGE Patterns CDC, public domain

28 Salmonella serotype Saintpaul 5 indistinguishable isolates

29 CDC, public domain

30 Questions for Thought

31 Salmonella Outbreaks Questions 1. In 1975, the FDA banned commercial distribution of small turtles (shell < 4 in). This FDA ban prevents how many estimated cases of salmonellosis among children each year? A. 10,000 B. 25,000 C. 50,000 D. 75,000 E. 100,000 CDC Image site, public domain

32 Salmonella Outbreaks Questions 2. Stringent procedures for cleaning and inspection of eggs were implemented in the 1970s. Since that time Salmonella outbreaks have been associated with: A. Raw unpasteurized eggs B. Grade A eggs with intact shells C. Egg shell surfaces D. Undercooked egg whites and yolks E. All of the above CID 2006:43 pg 512

33 Salmonella Outbreaks Questions 3. All of the following have been associated with major Salmonella outbreaks in the past 2 years except: A. Baby chicks B. Chocolate bars C. Fruit salad D. Puffed rice cereals E. Veggie booty

34 Salmonella Outbreaks Questions 4. What is the average number of cases of salmonellosis suspected to occur in the US each year? A. 40,000 B. 100,000 C. 500,000 D. 1,000,000 E. 4,000,000 CDC, public domain

35 Salmonella Outbreaks Questions 5. A recent salmonellosis outbreak in the Omaha area is suspected to be associated with which product? A. Alfalfa sprouts B. Peanut butter C. Pot pies D. Raw tomatoes E. Serrano peppers Salmonella serotype Saintpaul

36 Major Salmonella Outbreaks Serotype Product No. Time Tennessee Peanut butter 425 (44 states) 8/06-2/07 Wandsworth Veggie booty 65 (20 states) 6/07-7/07 Schwarzengrund Dry pet food 62 (18 states) 1/06-9/07 I 4[5],12:i:- Banquet pot pies 272 (35 states) 1/07-10/07 Litchfield Cantaloupe 51 (16 states) 1/08-4/08 Agona Malt-O-Meal cereals 28 (15 states) 1/08-5/08 Saintpaul Peppers 1438 (43 states) 4/08-8/08 Typhimurium Peanut butter products (44 states) 10/08-3/09 + Saintpaul Alfalfa sprouts (13 states) 2/09-5/09 +

37 Outbreak Investigation Salmonella serotype Typhimurium

38 Typical Outbreak Investigation Confirm outbreak existence Select a case definition Count cases and define population at risk Perform a case-control study Analyze data collected Formulate hypothesis Collect specimens for laboratory analysis Institute control measures Provide and communicate recommendations

39 Outbreak Investigation Salmonella serotype Typhimurium Confirm the outbreak Are there cases in excess of expected baseline? November 10, 2008 the PulseNet staff noted a multistate cluster of Salmonella serotype Typhimurium with an unusual DNA fingerprint. Select a case definition A lab confirmed infection of S. Typhimurium with the outbreak strain in a person with illness onset date on or after September 1, 2008.

40 Outbreak Investigation Salmonella serotype Typhimurium Count cases and define population at risk Epi curve

41 Outbreak Investigation Salmonella serotype Typhimurium Case-control study Collect risk information Short-form and long-form questionnaire Information includes Food items eaten Places eaten Illness data Date illness began Symptoms Presentation to your physician Other household contacts

42 Analyze data Time Place Person Outbreak Investigation Salmonella serotype Typhimurium Formulate hypothesis Suspect peanut butter and peanut paste to include roasted peanuts and other peanut products

43 Outbreak Investigation Salmonella serotype Typhimurium Collect specimens for laboratory analysis Environmental investigation Food products Manufacturing facility Patient specimens Stool Analyze isolates PFGE analysis indistinguishable PFGE patterns for isolates that were epidemiologically linked

44 Outbreak Investigation Salmonella serotype Typhimurium Institute control measures More than 2600 peanut-containing products produced by a variety of companies may have been made with the ingredients recalled by Peanut Corporation of America (Blakely, Georgia) Recalled products can be found on the FDA website Provide recommendations Consumers Retailers Directors of institutions and food service establishments Manufacturers Communicate findings CDC website on Salmonella investigations Local news

45 Timeline

46 CDC s Role in Food Safety Multiple agencies within the Dept. of HHS CDC Gathers data on foodborne illnesses Investigates foodborne illnesses and outbreaks Monitors effectiveness of prevention and control efforts FDA Food safety regulatory agency Agency within the USDA Food Safety and Inspection Service Food safety regulatory agency Note.CDC is NOT a food safety regulatory agency

47 *Investigation ongoing Salmonella serotype Typhimurium *

48 Salmonella as a Bioweapon? Historical example Typhoid Mary Mallon Early 1900 s House maid in New York Worked for 7 families 22 cases of typhoid fever 1 death Told not to work as a food handler Caused a second outbreak Authorities admitted her Individual terrorist??

49 Bioweapon Historical example 1984 Rajneeshee Bioterror Attack Food poisoning 751 individuals in Dalles, Oregon Salmonella serotype Typhimurium Poisoned salad in 10 restaurants Incapacitate voters so their candidates win a county election Followers of Bhagwan Shree Rajneeshee Significance 1 st bioterrorist attack in the US Largest bioterrorist attack in US history Wikipedia, Rajneeshee Bioterror Attack

50 CDC Emergency Preparedness and Response Program

51 Salmonella as a Bioweapon? Pathogen accessible and easy to grow Easy to weaponize Centralized food production Unmonitored food supply Rapidly and widely distributed Confusion with naturally occurring outbreak Terrorists can confuse public health officials No food product is safe Fresh fruits and vegetables Processed food additives

52 Combat Salmonella Bioterrorism National disease surveillance system PulseNet Laboratory Response Network Coordinated by CDC/APHL Public Health Laboratories City, county, state

53 Personal Protection

54 What can I do to prevent salmonellosis? Cook poultry, ground beef, and eggs thoroughly Do not eat or drink foods containing raw eggs Wash hands, kitchen work surfaces, and utensils with soap and water After contact with raw meat or poultry Wash hands with soap after handling reptiles, birds, or baby chicks Also after contact with pet feces Do not work with raw poultry or meat, and an infant at the same time

55 What in the World is Going on with Salmonellosis? PulseNet Program Allows outbreak strains to be recognized nationally Increased cooperation among states Better communication among federal partners More aware public What it is NOT? Our food supply is not necessarily more contaminated than in the past

56 Salmonellosis and Nebraska NEJM, 2000;342:1242 A program to promote appropriate antibiotic use in veterinary medicine and animal agriculture

57 Wash Your Hands!!

58 Humpty Dumpty by R. Wayne Edwards January 1999 Humpty Dumpty lay on the ground A crushed and broken fella. No one wanted to put him together 'Cause he had salmonella. Questions and Comments?

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