Shiga Toxin-producing E. coli O104 (STEC O104:H4) Infections in U.S. Travelers Returning from Germany
To: Vermont Healthcare Providers and Clinical Laboratories
From: Patsy Kelso, PhD, State Epidemiologist for Infectious Disease
Date: June 06, 2011
– Please Distribute Widely –
CDC is monitoring a large outbreak of Shiga toxin-producing Escherichia coli O104:H4 (STEC O104:H4) infections ongoing in Germany. As of May 31, 2011, the Robert Koch Institute reported 470 patients with hemolytic uremic syndrome (HUS), and nine deaths. The strain of STEC causing this illness, STEC O104:H4 is very rare. The illness it causes is similar to that caused by E. coli O157:H7.
CDC is not aware of any cases of STEC O104:H4 infection ever being previously reported in the United States. However, to date four cases of HUS in the U.S. have been reported in people who recently traveled to Germany. CDC is working with state health departments to learn more about these suspected cases and obtain bacterial isolates for further characterization. There have been no reported cases to date in Vermont.
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 improve within 5 to 7 days, but some patients go on to develop HUS, usually about a week after the onset of diarrhea. The classic triad of findings in HUS is acute renal damage, microangiopathic hemolytic anemia (evidence of schistocytes and helmet cells on peripheral blood smear), and thrombocytopenia.
To ensure STEC infections are detected and characterized as completely as possible, and to improve patient outcomes, we ask Vermont healthcare providers and clinical laboratories to do the following:
- Test stool from patients with acute community-acquired diarrhea for STEC O157:H7. These stools should be simultaneously assayed for non-O157 STEC with a test that detects the Shiga toxins or the genes encoding these toxins. If Shiga toxin testing is not available at a clinical laboratory, preserved stool may be sent to the Vermont Department of Health Laboratory for Shiga toxin testing. Contact the Lab (802-863-7560) to order collection kits.
- Do not prescribe antibiotics to patients with suspected STEC infections until complete diagnostic testing has been performed and STEC infection has been ruled out. Some studies have shown that administering antibiotics in patients with STEC infections might increase their risk of developing HUS. However, clinical decision making must be tailored to each individual patient. There may be indications for antibiotics in patients with severe intestinal inflammation if perforation is of concern. Of note, isolates of STEC O104:H4 from patients in Germany have demonstrated resistance to multiple antibiotics.
- Report all patients with Shiga toxin-positive diarrheal illness or HUS, regardless of a travel history to Germany, to the Vermont Department of Health at (800) 640-4374.
- Report and send E. coli O157:H7 isolates and Shiga toxin-positive samples to the Vermont Department of Health Laboratory as soon as possible for additional characterization.
- Forward specimens or enrichment broths in which Shiga toxin or STEC are detected, but from which O157:H7 STEC isolates are not recovered, to the Health Department Laboratory as soon as possible for recovery of non-O157:H7 STEC isolates.
It is often difficult to isolate STEC in stool by the time a patient presents with HUS. Immunomagnetic separation (IMS) has been shown to increase recovery of STEC from HUS patients. If necessary, the Health Department Laboratory will forward stool for any patient with HUS without a culture-confirmed STEC infection to the CDC for IMS. In addition, serum can be sent to CDC through the Health Department Laboratory for serologic testing of common STEC serogroups.