How To Stop The Superbugs

Global contagions always start off small, and like most small things, they’re easy to miss. The patient in Hamburg who went to the hospital on May 18 complaining of diarrhea, cramps and vomiting and was first suspected of having an inflammatory bowel condition would likely have gone unnoticed. But when four more patients in the same city became ill over the next two days with similar symptoms, German health officials started to pay attention.

Within weeks, the country — and soon the continent and the rest of the world — had a disaster on its hands, battling one of the biggest outbreaks ever of deadly E. coli bacteria. The infection has spread to a dozen countries, sickened more than 2,600 people and caused 25 deaths. One American has a confirmed case of the bug, and three others in the U.S. who recently visited Hamburg may have gotten sick from it as well. Authorities know what is responsible — a particularly nasty and rare version of E. coli called O104:H4 — but figuring out how this pathogen made its way into the food supply is a trickier challenge. First it was Spanish cucumbers — but then it wasn’t. Then it was German sprouts, except it wasn’t those either — unless maybe it really was, some unconvinced health officials still warn, as the investigation continues. In both cases, smart epidemiological tracking pointed straight to those suspects, but DNA testing failed to nail them. Russia, which is hoping for membership in the World Trade Organization, took a characteristically extreme approach, banning imports of all European Union produce. U.S. consumers are holding their breath, knowing that an increasingly globalized food market means that E. coli in Hamburg could be just a single transatlantic shipment away from becoming E. coli in Houston or Harrisburg. And given the most recent report from the U.S. Centers for Disease Control and Prevention (CDC), that worry may be justified.

In its latest evaluation of food-borne illnesses, the agency reports that in the past 15 years, outbreaks of salmonella infection in the U.S. from contaminated foods such as eggs, meat, poultry and nuts have not declined, despite efforts to improve education about safe handling of food. And while a newly passed law gives the Food and Drug Administration expanded authority to inspect, test and hold imported foods until they are deemed safe to eat, budget cuts threaten to strip the agency of those powers before it can exercise them. President Obama requested $955 million for food-safety measures in his most recent budget, but the House Appropriations Committee slashed that request to $750 million, or $87 million below what the agency is already investing in the area. Still, while it’s true that our food supply faces serious challenges, the U.S. has some advantages over the E.U. when it comes to preventing this kind of disaster.

Europe’s response to the current outbreak has been so scattered mainly because there’s no single authority in charge — either across the continent or within Germany. The Robert Koch Institute in Berlin is the nation’s federal authority for disease control, but state health officials are conducting their own tests and often release their findings directly to the public. “There is no central network to coordinate the response to an E. coli outbreak on a national level,” says Flemming Scheutz, director of the World Health Organization’s E. coli research center at Statens Serum Institute in Copenhagen. As an E.U. member country, Germany is obliged to report food-contamination incidents to the European Commission, which has its own disease-control center and alert system for outbreaks. Piecemeal surveillance leads to a fragmented investigative network, which, coupled with the pressure to find a culprit fast, can easily result in the kinds of unconfirmed reports that have occurred in the past few weeks.

The U.S. is hardly monolithic when it comes to dealing with food-borne contagions; 50 states means 50 state health departments that can get involved in an investigation. But the CDC links with local officials and serves as a centralized clearinghouse for information and laboratory testing. In a 2006 outbreak of a strain of E. coli that sickened nearly 200 people, it took the agency and two state health departments just six days from the first identification of clusters of illness to trace the contamination to spinach at specific processing plants.

But good coordination is not always enough. No matter how strong food-safety policies are, bugs like E. coli can find their way into meat and other foods, especially fruits and vegetables such as spinach, peppers and onions. In fact, we live with certain colonies of E. coli in our gut, and the bugs are essential to helping us digest and break down food. But E. coli is notoriously promiscuous, adept at swapping genetic material not just with other strains but with other organisms as well. Crowded conditions for cattle, sheep and other livestock that can harbor colonies of E. coli provide the ideal environment for games of genetic roulette. And all of that makes the bacterium especially nimble, able to mutate easily into ever more destructive forms. The U.S. got a taste of that nightmare in 1993, when E. coli O157 caused its first significant outbreak of illness, with others to follow — principally through hamburger meat and spinach.

The current bug, O104:H4, is even deadlier. A rare strain that in the past has caused illness in limited numbers only, O104:H4 combines a powerful toxin known as Shiga toxin with a form of bacterial glue that sticks the organism to the gut wall for up to two weeks, providing it with the perfect spot from which to release its poison. Once in our bodies, the toxin breaks down red blood cells, leading to clots and strokes, and targets kidney cells, causing a form of kidney failure known as hemolytic uremic syndrome (HUS) — and sometimes death. Some patients who develop HUS and recover may need dialysis for the rest of their lives. “In terms of the numbers of cases of HUS, what we’re seeing in Germany is much bigger than anything we’ve seen before,” says Dr. Robert Tauxe of the CDC. “That does surprise me.”

In most E. coli outbreaks, contamination starts with an infected ruminant — a cow, sheep or goat. Although it doesn’t become ill, once the animal is slaughtered, the raw meat can cause illness, and people or utensils that come into contact with the raw meat can spread the contamination. Cooking contaminated meat generally kills E. coli, but increasingly, the bacteria have been showing up in produce that most people eat raw. Farmers often use manure to fertilize vegetable crops, and contaminated feces could spread the bacteria to these foods. Infected runoff from agricultural pastures could also reach crops and deposit E. coli in the roots or leaves of plants. Given that we’re in the midst of the spring and summer growing season, more people are eating fresh produce, which may be a reason so many have become ill.

And treating these people isn’t easy. Antibiotics aren’t always the answer, since the drugs may merely provoke the bugs and lead them to pump out even more toxin. Much of the health care patients need involves hydration with intravenous fluids and treatment of blood clots, strokes and kidney failure with the appropriate supportive therapies.

As the number of new cases starts to abate, many countries, including the U.S., will continue to put German imports under special scrutiny. Meanwhile, individuals can take preventive action like washing their hands before and after handling raw food, thoroughly washing produce — especially the kinds eaten raw — and cooking food properly. “The tragic E. coli outbreak in Europe reminds us that investing in prevention of food-safety problems is ultimately the only way to provide the protection that consumers expect and to avoid economic and social disruption,” says Dr. Elisabeth Hagen, Under Secretary for Food Safety at the U.S. Department of Agriculture. For now, the U.S. maintains a bit of an edge in this kind of preparedness, but it’s an edge that could erode fast.

Disease Detectives
Tracing an outbreak back to its source

1. Identifying the cases
Once public-health officials suspect an outbreak, they start creating a profile of all possible cases. Symptoms the victims share can help point to a possible cause, in this case, E. coli. Both sick and healthy people receive questionnaires asking what they ate, where they ate and where else they’ve been.

2. Targeting the source
With questionnaire data in hand, investigators refine their search, trying to trace where the infected food came from. Which grocery stores or restaurants did the sick individuals frequent? Did they all visit a particular farm or other facility?

3. Record search
Investigators go to the restaurants or stores and sift through shipment records to find out the origins of the foods. Since most such businesses get shipments from various distributors, this can take days or even weeks.

4. Narrowing the search
Investigators go to distributors’ warehouses and inspect their records and current supplies. They study packaging and try to determine which farms provided which products at the key times.

5. At the source
The final investigations take place on the farms where the food was grown. The teams inspect crops (including irrigation and proximity of animals to vegetable fields). They look at collection methods and facilities as well as packing methods to determine if the bacteria came from infected animals or was spread by unsanitary human handling.