Findings presented are considered preliminary and subject to change

Transcription

1 Cracking the Case: Multi-state Outbreak of SalmonellaEnteritidis associated with Eggs Thai-An Nguyen, MPH Centers for Disease Control and Prevention Outbreak Response and Prevention Branch Outbreak Response Team Jeffrey Higa, MPH California Department of Public Health Infectious Diseases Branch Disease Investigations Section OutbreakNetConference September 22, 2011 Findings presented are considered preliminary and subject to change

2 Salmonella Most common bacterial cause of foodborne disease in the United States ~ 1 million illnesses and 370 deaths annually* >2,500 serotypes Enteritidis one of most common * Scallan E, Hoekstra RM, Angulo FJ, Tauxe RV, Widdowson M-A, Roy SL, et al. Foodborne illness acquired in the United States major pathogens. Emerg Infect Dis Jan

3 Salmonella Enteritidis (SE) 6,000 to 7,000 laboratory confirmed infections each year ~18% of all U.S. salmonellosis infections Outbreaks often associated with chicken or eggs Silent infection of ovary of hen Healthy hens Eggs can be internally contaminated

4 Challenges SE exhibits high genetic homogeneity Poorly differentiated by common subtyping methods Difficult to differentiate potential outbreak from non-outbreak cases SE pattern 4 most common PFGE pattern cases reported weekly to CDC Case definition based on PFGE subtype has high probability of including non-outbreak cases SE often associated with chicken or eggs Both commonly consumed Eggs stealth ingredient in many prepared dishes Case-control study of sporadic cases unlikely to identify source

5 Mean Number of SE Pattern 4 Isolates Reported to PulseNet Annually, U.S., Number of Isolates Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

6 Mean Number of SE Pattern 4 Isolates Reported to PulseNet Annually, U.S., Number of Isolates n =1,639 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

7 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., Isolates Number of Isolates June 2010: CA notes an increase in SE infections and begins investigations 5-year baseline mean 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

8 California: Salmonella and PFGE 37 million population 61 local health jurisdictions (LHJs) 5000 salmonellosis cases reported annually 5 public health labs certified for PFGE 444 LHJ labs: Los Angeles, Orange, San Diego, and Santa Clara counties 4CDPH Microbial Diseases Laboratory (MDL) PFGE not done for all Salmonella isolates 8

9 How it began.. In June 2010, MDL noted increase in SE isolates 4PFGE of SE isolates conducted MDL identifies several isolates from N. CA with SE pattern 0004 S. CA labs also identify several isolates with SE pattern 0004 Some initial clues 4NC restaurant cluster (April 2010) Implicated meringue made from pasteurized egg product OB SE strain (pattern 0004) isolated from meringue 4Santa Clara County, CA (May 2010) Illnesses for two separate events held at common venue 9

10 Our Approach for SE Investigation Because the strain was so common Epi data collected regionally and compared 4 San Francisco Bay area counties 4 Los Angeles County 4 Orange County 4 San Diego County Restaurant clusters of 2 or more cases investigated 4 Environmental health inspection 4 Trace back of eggs initiated 10

11 Two Outbreaks, One Venue Two events held at same Santa Clara County venue 4 May 28: University graduation dinner 4 May 29: High school senior prom Initially, 5 patients with OB strain of SE identified 42 attended grad dinner 42 attended prom 41 food server who became ill after the second event Different types of menus 4 Grad dinner: sit down meal salad, entrée, dessert 4Prom: appetizers/snacks pasta bar, chocolate dipping fountain 11

12 Common Menu Items Comparison of menus for 2 events revealed only 3 common food items. Romaine lettuce hearts Fresh strawberries Custard desserts Mini fruit tartlets (grad dinner) Profiteroles (prom) 12

13 Prom Case-Control Control Study Case-control study conducted for prom 4Randomized list of 634 seniors 4All interviewed using menu-based questionnaire 81 attendees interviewed - analysis limited to persons who ate at least one item at the prom 415 cases 432 controls Profiterole only significant item 4OR = 12.0; 95% CI =

14 Custard Custard and desserts prepared by off-site bakery Profiteroles and mini fruit tartlets ordered for total of people for two events Custard preparation (both desserts) 4 Pasteurized sugared egg product usually used 4 Shell eggs used when not enough pasteurized product 4 Eggs combined with milk, sugar, and vanilla and boiled for 5 minutes probe thermometer not used to test temp Shell eggs traced back to Wright County Egg in Iowa 14

15 San Diego County Clusters 3 restaurants reported as exposures by 2 or more patients; several had egg dishes Environmental health investigators inspected restaurants to determine source of eggs at time of exposures 4Pictures taken of egg boxes on-site at time of investigation Restaurants initially appeared to have different egg sources 15

16 Don t judge an egg by its carton! Restaurant Egg Supplier/Distributor Plant 1 Egg Company A Los Angeles, CA dist. by Distributor E P 1946 Quality Egg LLC Site 2 Egg Company B 2 packed by Quality Egg LLC dist. by Distributor F P 1942 Quality Egg LLC Site 3 3 Egg Company C from Distributor G Lakeside, CA Egg Company D from Wright County Egg #1 dist. by Distributor H College Point, NY P 1026 P 1720 Quality Egg Environ Division Quality Egg LLC Site 1 Quality Egg LLC does business as Wright County Egg

17 The Telltale Labels Photos courtesy of Brad Richardson (San Diego County Env. Health)

18 Los Angeles County Cluster Several patients that possibly worked in entertainment industry identified 43 reported working on the same movie Catering truck on-site at filming locale 4Omelet bar 4Eggs Catering company purchased eggs from Distributor J Distributor J reported that Wright County Eggs was their supplier 18

19 CA Pieces Fall into Place Wright County Egg July 29: 5 facilities linked to WCE; WCE eggs source of eggs during exposures or on-site at time of inspection 4Bakery (prom and graduation dinner) 4Dim sum restaurant 43 San Diego County restaurants July 30: Los Angeles County confirmed that caterer for movie set also used WCE eggs July 30: discuss findings with CDC, FDA, and USDA Preliminary trace back of shell eggs at 6 of 6 facilities associated with CA clusters linked to Wright County Egg. 19

20 California Egg Consumption Source of Eggs 15% California Iowa Other 20% 65% California is an egg deficit state; i.e., CA does not produce enough eggs for consumption and imports from other states.

21 Salmonella Enteritidis Isolates received by CDPH Microbial Diseases Laboratory by Month of Specimen Collection, CA 2010 (N=1257) No. of Isol lates yr avg, Egg recall initiated on August Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Month of Specimen Collection

22 Restaurant or event clusters, April 10-September 7, 2010 Cluster

23 Restaurant or event clusters, April 10-September 7, 2010 Cluster

24 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., Isolates of Isolates Number May 20: MN identifies 2 SE cases through routine surveillance 5-year baseline mean 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

25 Minnesota Cluster Minnesota Department of Health (MDH) Environmental Health Services (EHS) initiated investigation EHS sanitarians conducted an environmental assessment, collected credit card receipt records Case-control study conducted to evaluate food items that may have been associated with illness Cases, meal companions, other patrons identified during May 5-7 were interviewed about foods eaten and GI illness

26 Minnesota Cluster Seven cases and 34 controls identified through routine surveillance and investigation interviews with meal companions Variety of foods consumed Chile rellenos, enchiladas, tacos, burritos Chile relleno consumption significantly associated with illness 4/7 cases vs. 2/34 controls OR=22.7, p < 0.01

27 Minnesota Cluster Chile relleno preparation process Chile peeled, stuffed with cheese, frozen Frozen chile dredged in flour, dipped in egg whites, deep fried, refrigerated Oven-warmed, covered with sauce, microwaved Shell eggs used to create pooled egg whites Cross-contamination, poor handwashing Traceback to identify egg supplier initiated

28 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., Isolates Number of Isolates July: CO investigates a cluster of SE 5-year baseline mean Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

29 Colorado Cluster Case-control study conducted 29 cases and 101 controls identified through routine surveillance and investigation interviews with restaurant patrons Consumption of Restaurant B s rattlesnake cake, game plate, crème brûlée, buffalo empanadas statistically significant Stratified by consumption of rattlesnake cake, no longer significant Rattlesnake cake statistically implicated OR=18.7, p < 0.001

30 Colorado Cluster Significant potential for contamination Prepared using snake meat Bound together with pooled shell eggs Served with aioli sauce containing raw eggs Garnished with microgreens 2 food specimens submitted for laboratory analysis Only rattlesnake cakes yielded SE Traceback to identify egg supplier initiated

31 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., 2010 Number of Isolates Isolates 5-year baseline mean 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

32 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., 2010 Number of Isolates n =3,578 Isolates 5-year baseline mean Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

33 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., 2010 Number of Isolates Estimated surplus cases n = 1,939 Isolates 5-year baseline mean Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

34 Restaurant or event clusters, April 10-November 30, 2010 Cluster

35 Suspect Food Items in Clusters 8 case-control studies 7 implicated eggs 1 inconclusive 2 cohort studies 1 implicated eggs 1 inconclusive 19 food histories 6 identified exposure to eggs 1 identified exposure to chicken dishes 1 identified exposure to ill food handlers 11 inconclusive

36 Suspect Food Items in Clusters Eggs as main ingredient Breakfast tacos Omelet Eggs as stealth ingredient Vietnamese sandwiches Tofu pancake Seafood tofu hot pot Common source of eggs determined for 17 clusters Difficulties identifying suppliers

37 Restaurant or event clusters, April 10-November 30, 2010 Cluster

38 Restaurant or event clusters, April 10-November 30, 2010 Cluster

39 Restaurant or event clusters, April 10-November 30, 2010 Cluster

40 Shell Egg Regulation Shell eggs regulated by US Food & Drug Administration (FDA) SE regulation initially proposed in 2004 Prevention of Salmonella Enteritidis in Shell Eggs During Production, Transportation, and Storage Prevent SE contamination of eggs during production Prevent further growth during transportation, storage Require record keeping of compliance and testing results Rule became effective on July 9, 2010 Producers with 50,000+ hens compliant

41 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., Number of Isolates FDA inspects Wright County Egg Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

42 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., Number of Isolates FDA inspects Hillandale Farms Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

43 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., Number of Isolates ~600 samples, 11 positives Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

44 FDA Inspectional Observations

45 Manure approximately 4 feet high to 8 feet high FDA Inspectional Observations

46 FDA Inspectional Observations Manure approximately 4 feet high to 8 feet high The outside access doors had been pushed out by the weight of the manure

47 FDA Inspectional Observations Manure approximately 4 feet high to 8 feet high The outside access doors had been pushed out by the weight of the manure Live and dead flies too numerous to count

48 FDA Inspectional Observations

49 Two live rodents were observed FDA Inspectional Observations

50 FDA Inspectional Observations Two live rodents were observed Liquid manure was observed streaming out

51 Number of SE Pattern 4 Isolates Reported to PulseNet, U.S., 2010 Number of Isolates August 13-20: 550 million shell eggs recalled Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Week of Culture Isolation

52 Egg Distribution Packaging and repackaging under different labels common Breakage during transportation Complicated distribution Wright County eggs were produced by Wright County Egg and Hillendale Farms, and packaged by Farm X in 6- egg, dozen-egg, 18-egg and 2 ½ dozen-egg cartons, in 2 ½ dozen and 5-dozen egg sleeves, in 15-dozen bulk cubes and in 30- dozen cases Wright County Egg sold under 13 brand names Hillandale Farms sold under 3 brand names

53 Conclusions More than 56,000 sickened One laboratory-confirmed case: 29 unreported cases* Nationwide outbreak caused by shell eggs Shell eggs important vehicle for SE transmission First nationwide recall of shell eggs in the United States Focus on restaurant and event clusters critical to outbreak response * Scallan E, Hoekstra RM, Angulo FJ, Tauxe RV, Widdowson M-A, Roy SL, et al. Foodborne illness acquired in the United States major pathogens. Emerg Infect Dis Jan

54 Acknowledgments California Local health departments California Department of Public Health California Emerging Infections Program California Department of Food and Agriculture Minnesota Local health departments Minnesota Department of Health Minnesota Department of Agriculture Colorado Local health departments Colorado Department of Health and Environment Colorado Department of Agriculture U.S. State and Local Health Departments U.S. State Departments of Agriculture U.S. Centers for Disease Control and Prevention U.S. Food and Drug Administration

55 Thank you For more information please contact: Thai-An Nguyen, MPH Centers for Disease Control and Prevention Division of Foodborne, Waterborne and Environmental Diseases Outbreak Response and Prevention Branch Outbreak Response Team (404) Jeffrey Higa, MPH California Department of Public Health Division of Communicable Disease Control Infectious Diseases Branch Disease Investigations Section (310) Findings presented are considered preliminary and subject to change