Foodborne Outbreak of E. coli Infections and Hemolytic Uremic Syndrome in Germany, 2011

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1 Foodborne Outbreak of E. coli Infections and Hemolytic Uremic Syndrome in Germany, 2011 Kirk Smith, DVM, MS, PhD Supervisor Foodborne, Vectorborne and Zoonotic Diseases Unit Minnesota Department of Health June 2011

2 Background Types of pathogenic E. coli worldwide Shiga toxin-producing E. coli in Minnesota O157 Non-O157 Hemolytic Uremic Syndrome in Minnesota

3 Diarrheagenic E. coli Categories Enterotoxigenic ETEC Enterohemorrhagic EHEC Aka Shiga toxin-producing E. coli (STEC) Enteropathogenic EPEC Enteroaggregative EAggEC or EAEC Enteroinvasive EIEC Diffusely adherent DAEC

4 E. coli O157:H7 One type of Shiga toxin-producing E. coli Important cause of hemorrhagic colitis Primary cause of post-diarrheal hemolytic uremic syndrome in the United States

5 Selected Bacterial Enteric Pathogens Reported to MDH, Campylobacter Number of Cases Shigella Salmonella E. coli O157:H Year

6 E. coli O157:H7 Primary reservoir = cattle other ruminants (sheep, goats, deer) Ground beef is most common vehicle, but anything contaminated by ruminant feces can be a source direct contact with calves, goats, sheep sprouts, leafy greens, lake water, unpasteurized milk and apple cider, etc. spreads readily in child care settings fecal-oral, person-to-person

7 Hemolytic Uremic Syndrome (HUS) Most common cause of kidney failure in children Characterized by: Thrombocytopenia Microangiopathic hemolytic anemia Acute kidney failure

8 Number of Post-Diarrheal HUS Cases, Minnesota, , by E. coli O157 Status O157 Not identified O157 Identified 59% culture confirmed E. coli O157 Number of Cases Year

9 Demographics of HUS cases, Minnesota, (n=215) 65% female Median age = 5 years (range, years) 61% of cases from greater Minnesota Duration of hospitalization: median, 11 days (range, days) Case fatality rate: 5.6% 6 children, 6 adults

10 Percentage of E. coli O157 Infections Resulting in Hemolytic Uremic Syndrome by Age Group, Minnesota, % % of O157 Infections Resulting in HUS % 4.2% 0.4% 1.5% All Ages Age group (years) 1.3% 3.9% 2.4% 4.3% 5.8%

11 Non-O157 Shiga Toxin-Producing E. coli (STEC) Known causes of gastroenteritis Implicated in outbreaks in the U.S. Special studies indicate that non-o157s are more common than O157 in Minnesota Not as severe as O157 overall, but some strains can be; can cause HUS Many different serotypes Are not detected by standard stool culture methods in clinical laboratories

12 Non-O157 Shiga Toxin-Producing E. coli (STEC) In recent years, clinical laboratories have been adding or switching to non-culture methods for STEC (that detect Shiga toxin) Non-O157s can now be detected by clinical labs Most of the tests used cannot differentiate O157 from non-o157 Need to be sent to public health labs

13 Number of Non-O157 STEC Cases, FoodNet, Gould, CDC

14 Non-O157 STEC have Emerged as a Cause of HUS in Minnesota since HUS cases due to non-o157 STEC 10 children 2 fatalities Various serotypes Likely ruminant (e.g., cattle, goat) reservoir

15 Enteroaggregative E. coli EAEC First described in 1987 Strains are very heterogeneous Significant cause of persistent diarrhea in developing regions Children and adults residing in developing regions International travelers to developing regions Children residing in industrialized regions

16 E. coli Outbreak in Germany, May-June 2011

17 E. coli Outbreak Investigation Timeline May 20 Germany detects significant increase in # of patients with HUS and bloody diarrhea caused by STEC since May 2 May 22 Outbreak announced

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19 Case Counts as of June 14 3,332 cases 818 people with HUS (781 in Germany) 36 deaths (1.1% case fatality rate) 100 patients with such severe kidney damage that will need kidney transplants or dialysis entire life

20 Outbreak Strain of E. coli Serotype O104:H4 Very rare Unusual Bug Combination of Enteroaggregative E. coli and STEC Lacks 2 usual virulence factors of STEC (intimin and hemolysin) EAggEC plus Shiga toxin Resistant to many antimicrobials Contains ESBL Reservoir humans vs. animal?

21 % of Cases with HUS Highly Virulent Strain? 818 HUS cases / 3,332 total cases = 24.5% Likely hundreds or thousands of milder cases not diagnosed Gastrointestinal symptoms only May not have gone to doctor May not have been tested True % of cases that developed HUS likely quite lower

22 E. coli Outbreak in Germany Case 68% female Characteristics 88% adults aged >20 years Attack rates highest in year age group Northern Germany Illness onset dates range from May 1 to June 6 New cases declining during second week of June

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24 May 25 Investigation Timeline Case-control study: lettuce, tomatoes, sprouts statistically significant May 26 3 of 4 organic Spanish cucumbers test positive for Shiga toxin gene Cucumbers considered source May 31-June 1 STEC from Cucumbers not outbreak strain

25 June 4 Investigation Timeline Sprouts suspected based on link between outbreak restaurants/cafeterias to one sprout producer in northern Germany June 10 Announce definitively that bean and seed sprouts are outbreak vehicle Restaurant cohort study Isolation of outbreak strain from open package of sprouts from case household garbage Lettuce, tomato, cucumber advisory lifted

26 E. coli O157:H7 Outbreak Associated with White Radish Sprouts in Japan, ,680 cases 121 HUS cases (1%) 3 deaths

27 E. coli O157:H7 Outbreak Associated with Jack-in-the-Box Hamburgers, Western States, 1993 >700 cases >50 HUS cases (7%) 4 deaths

28 Multi-state Outbreak of E. coli O157:H7 Infections Associated with Spinach, cases 26 states affected Onsets 8/1-9/15/ (71%) female 103 (51%) hospitalized 31 (16%) HUS 3 deaths

29 E. coli O157:H7 MN744 Case- Patient Characteristics (n=11) Age, median (range) Male Bloody diarrhea Hospitalized HUS all 3 female cases had HUS (ages 4, 9, 20 yrs) 19 yrs (1 85) 7 (63%) 10 (91%) 7 (63%) 4 (36%)

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