Investigation Update: Outbreak of Shiga toxin-producing E. coli O104 (STEC O104:H4) Infections Associated with Travel to Germany

Updated June 7, 2011

Introduction

CDC is monitoring a large outbreak of Shiga toxin-producing Escherichia coli O104:H4 (STEC O104:H4) infections ongoing in Germany. The responsible strain shares virulence characteristics with enteroaggregative E. coli (EAEC). As of June 6, 2011, case counts confirmed by Germany’s Robert Koch Institute* include 642 patients with hemolytic uremic syndrome (HUS) – a type of kidney failure that is associated with E. coli or STEC infections – and 15 deaths.

In the United States, one confirmed and three suspected cases of STEC O104:H4 infections have been identified in persons who recently traveled to Hamburg, Germany, where they were likely exposed. One case of HUS in Massachusetts has been confirmed as matching the German outbreak strain. Among the three suspected cases, two are cases of HUS, one case each in Michigan and Wisconsin. The third suspected case, a person with Shiga toxin-positive diarrheal illness, is still under investigation.

CDC is working with state health departments to learn more about these suspected cases and obtain bacterial isolates from them for further characterization. In addition, CDC has alerted state health departments of the ongoing outbreak and requested information about any persons with either HUS or Shiga toxin-positive diarrheal illness, with illness onset during or after travel to Germany since April 1, 2011.

Investigation of the Outbreak

At this time, a specific food has not been confirmed as the source of the outbreak. Based on German epidemiologic and traceback investigations, several fresh produce items are currently under further investigation. On June 5, the Lower Saxony Ministry of Agriculture reported that the results of an investigation into the distribution chain of a local producer suggest the consumption of sprouts from a single farm may be associated with the outbreak there. Travelers to Germany should be aware that the German public health authorities have advised against eating raw sprouts, tomatoes, cucumbers, and leafy salads from sources in northern Germany until further notice. United States public health and regulatory authorities currently have no indication that any of these foods have been shipped from Europe to the United States.

The U.S. Department of Defense has been notified of this outbreak because of the presence of U.S. military bases in Germany; there are no known confirmed cases among U.S. military personnel or their dependents at this time. However, reports indicate that a small number of U.S service members in Germany with diarrheal illness are currently under investigation. For travel information related to this outbreak, please view the article on CDC Travelers’ Health Website.

Although rare, E. coli O104:H4 has been identified before. For example, in 2009 in the Republic of Georgia, culture of specimens from two patients who were part of a cluster of diarrheal illness yielded an E. coli O104:H4 strain that was similar to the current outbreak strain. That strain produced Shiga toxin, but had a different molecular fingerprint and was less resistant to antibiotics than the current outbreak strain in Germany. No clear outbreak was identified in the Republic of Georgia, and no food was identified as a source of infections.

Clinical Features/Signs and Symptoms

Any person who has recently traveled to Germany and has signs or symptoms of STEC infection or HUS should seek medical care and let the medical provider know about the outbreak of STEC infections in Germany and the importance of being tested for STEC. Symptoms of STEC infection include severe stomach cramps, diarrhea (which is often bloody), and vomiting. If there is fever, it usually is not very high. Most people get better within 5-7 days, but some patients go on to develop HUS—usually about a week after the diarrhea starts. Symptoms of HUS include decreased frequency of urination, feeling very tired, and losing pink color to skin and membranes due to anemia.

Key Resources

• Escherichia coli O157:H7 and other Shiga toxin-producing Escherichia coli (STEC)
• CDC E. coli Resources for Clinicians
• CDC Travelers' Health Website - "Outbreak Notice"
• Presentation -“Shiga Toxin-Producing Escherichia Coli Infections: What Clinicians Need to Know”
• MMWR - “Recommendations for Diagnosis of Shiga Toxin–Producing Escherichia coli Infections by Clinical Laboratories” [PDF - 287 KB]
• E. coli: Key publications [PDF - 227 KB]
• Description of the Steps In a Foodborne Outbreak Investigation
• FoodSafety.gov*
• Robert Koch Institute (Germany)*

CDC's Role in Food Safety

CDC leads federal efforts to gather data on foodborne illnesses, investigate foodborne illnesses and outbreaks, and monitor the effectiveness of prevention and control efforts. CDC is not a food safety regulatory agency but works closely with the food safety regulatory agencies, in particular, with the Food and Drug Administration of the U.S. Department of Health and Human Services and the Food Safety and Inspection Service of the U.S. Department of Agriculture. CDC also plays a key role in building state and local health department epidemiology, laboratory, and environmental health capacity to support foodborne disease surveillance and outbreak response. Notably, CDC data can be used to help document the effectiveness of regulatory interventions.