Doctors treating the world’s deadliest E. coli outbreak have little beyond water and dialysis machines to help them clear the contagion from patients, according to infectious disease specialists.
The new strain of E. coli, which has killed at least 18 people in Europe, produces a poisonous by-product called shiga toxin that damages the kidneys of some patients and requires the use of dialysis to scrub the blood clean. Some patients need transfusions after the bacteria dissolves their red blood cells, said Robert Tauxe, deputy director of food-borne illness at the U.S. Centers for Disease Control and Prevention.
Germany alone has reported 520 cases of the kidney ailment. Overall, 1,833 cases of E. coli infection have been confirmed, the European Centre for Disease Prevention and Control said today. In less severe cases, doctors use fluids to maintain hydration and stream the diarrhea-causing toxins through the body. Antibiotics don’t help, and can worsen the illness.
“It’s clearly a more severe disease than is normally seen because of this kidney failure association,” said Stephen Calderwood, chief of the infectious disease division at Massachusetts General Hospital in Boston. “There is some data that if you keep the patient hydrated it may lessen the kidney disease. What is recommended is supportive treatment -- no antibiotics but maintain hydration.”
Antibiotics can’t be used because they increase the release of toxins into the bloodstream, compounding kidney damage, Calderwood said. The one class of antibiotics that doesn’t do this, known as carbapenems, is unlikely to help with E. coli, though they may be useful for patients who are simultaneously fighting additional infections, he said.
Authorities are investigating a restaurant in Luebeck, Germany, as a possible source of cases in the outbreak, Luebecker Nachrichten reported today. Seventeen people fell ill in mid-May after eating at the restaurant in the northern coastal city, the newspaper said, without saying where it got the information. Investigators from the Robert Koch Institute and the Federal Institute for Risk Assessment arrived in Luebeck yesterday, the newspaper said.
Spokespeople at the Berlin-based Robert Koch Institute couldn’t be reached for comment today.
The new E. coli strain, previously identified in isolated cases but never linked to an outbreak, begins with symptoms similar to more common types of the bacteria. Diarrhea starts anywhere from two to seven days after eating tainted foods, though most cases occur in the three- to four-day range.
The diarrhea often contains blood and can be accompanied by fever, abdominal cramps and vomiting, Claudia Stein, director of health information, evidence and research at the World Health Organization in Geneva, said in a telephone interview.
“It makes your guts bleed; the bloody diarrhea is really a hallmark,” Stein said. “Somebody with bloody diarrhea should not wait. Go straight to their medical practitioner and report this, and then they have to be hospitalized.”
At the hospital, patients will be given fluids to begin the cleansing process, intravenously if necessary, she said.
All humans carry E. coli in their intestines, and those strains are usually harmless, according to the Stockholm-based European Centre for Disease Prevention and Control. Some variants cling to the walls of the intestine and produce toxins that cause illnesses ranging from diarrhea and nausea to the potentially fatal kidney complication, known as hemolytic uremic syndrome, or HUS.
In addition to the 520 German cases of the kidney illness linked to the spread of E-coli, another 31 have been reported in Sweden, Spain, Denmark, the U.K., the Netherlands and Poland, the European disease agency said today. Seventeen people in Germany and one in Sweden have died, the agency said.
By comparison, the biggest outbreak in the U.S. of a toxin- producing E. coli killed four children, gave 41 people HUS and sickened about 700. That event, linked to a different strain, occurred as the result of tainted meat served at the Jack in the Box Inc. fast-food chain in 1993.
When patients develop kidney damage from E. coli, it typically begins 5 to 10 days after the initial symptoms. In some cases, the diarrhea subsides before signs of kidney damage appear. That’s because it takes days for the toxin to be transported through the blood to the kidney and damage kidney cells, Calderwood said.
In the European outbreak, the kidney damage appears to be starting sooner than in previous outbreaks, he said. It may be that the strain can shed the toxins into the blood stream more quickly or more completely than in previous outbreaks, though more research is needed, he said.
Patients with kidney failure must be treated for weeks using dialysis machines, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
“The number of critical-care beds that are available for people are limited,” Osterholm said. “If this were to grow much larger, there certainly would be a challenge to the health- care delivery system of Germany.”
Most patients recover, though some sustain long-term kidney damage. Children who have recovered from past outbreaks can have long-term complications that include lifelong high blood- pressure, Calderwood said.
The outbreak hasn’t shown definitive signs of slowing, according to the WHO. Researchers are still trying to determine the source of the outbreak.
“The history of outbreak investigations in the U.S. shows that produce outbreaks can be very challenging to isolate the cause,” Caroline Smith DeWaal, director of food safety for the Center for Science in the Public Interest in Washington, said in a telephone interview. “Produce outbreaks can be very, very hard to identify the specific food source.”
People who were sickened ate more salad than healthy individuals, according to two studies of the German outbreak released by the Robert Koch Institute, Germany’s disease control agency. About 95 percent of the patients who became ill had eaten either lettuce, tomatoes or cucumbers, the institute said in an e-mailed statement.
The U.S. gets 0.2 percent of its produce from Germany and Spain, because the shelf life of fresh fruits and vegetables is short, said David Elder, the Food and Drug Administration’s director of regional operations, in a conference call with the news media. All produce from Germany and Spain is being checked by inspectors before it’s allowed to enter the U.S., he said.
Bans on imports of EU vegetables would be “disproportionate,” the European Commission said in a statement today. The commission’s Employment, Social Policy, Health and Consumer Affairs Council will discuss consolidating European efforts to address the outbreak at a meeting in Luxembourg on Monday, Commissioner John Dalli said in the statement.
Four cases of E. coli infection in the U.S. have been reported among people returning from trips to Germany, according to the U.S. Centers for Disease Control and Prevention.
E. coli spreads through fecal matter. Vegetables are sometimes infected during production by water tainted by bacteria from farm animals. It spreads human to human when people don’t wash their hands, most frequently in day care and in nursing homes, according to Calderwood.
Range of Ages
Most kidney damage historically has occurred among children, Calderwood said. A previous outbreak in Scotland affected adults, but primarily targeted people older than the age of 65. The Germany outbreak is unique because it’s affecting a broad range of ages of adults, mostly women, he said.
Washing vegetables is helpful to prevent sickness, though it doesn’t eradicate the bacteria, Osterholm said. A speck of microscopic bacterium is sufficient to infect a person, and rinsing vegetables offers inadequate protection, he said.
Cooked vegetables are safe to eat, according to the WHO. Cooked foods should be kept hot before eating and should be stored in a cold refrigerator afterwards.