passed, scientists discovered still more strains of
E. coli
that could cause diseases. Some strains attacked the large intestine. Others attacked the small intestine. Some lived harmlessly in the gut but could cause painful infections if they got into the bladder, sometimes creeping all the way up to the kidneys. Other strains cause lethal blood infections, and still others reach the brain and cause meningitis. The scale of their cruelty is hard to fathom.
Shigella
alone strikes 165 million people every year, killing 1.1 million of them. Most of the dead are children. I can only wonder what Theodor Escherich would have thought if he had discovered that many of the bacteria killing his young patients were actually his
Bacterium coli communis.
Although many strains of
E. coli
are deadly, one has earned more headlines in recent years than all the rest combined. It goes by the name of O157:H7, a code for the molecules on its surface.
E. coli
O157:H7 is the strain that makes petting zoos hot zones, that can turn spinach or hamburger into poison, that can cause organ failure and death. For all its notoriety, though, it’s relatively new to science.
In February and March 1982, 25 people in Medford, Oregon, developed cramps and bloody diarrhea. Doctors identified a strain of
E. coli
in some of the patients that had never been seen before. Three months later the same strain caused an outbreak in Traverse City, Michigan. The source of the bacteria proved to be undercooked hamburgers that the victims had eaten at McDonald’s restaurants. A pattern had emerged, and now scientists began to hunt for
E. coli
O157:H7 in samples of bacteria taken from patients in earlier years. Out of 3,000
E. coli
strains collected from American patients in previous years, 1 proved to be O157:H7. It came from a woman in California in 1975. Searches in Great Britain and Canada turned up 7 more cases, but none before 1975.
O157:H7 slipped back into obscurity for a decade. It emerged again in the mid-1990s in a series of outbreaks across the world. In 1993, an outbreak spread in undercooked restaurant hamburgers in Washington State sickened 732 people. Four of them died. Scientists found that cows, sheep, and other livestock can carry O157:H7 in their intestines without getting sick. An estimated 28 percent of cows in the United States carry O157:H7. It can move from animal to human through bad butchering. If a cow’s colon is nicked during slaughter, the bacteria can get mixed into the meat. As meat from many cows gets blended together,
E. coli
O157:H7 can spread through tons of beef. Most of the bacteria are killed off by cooking. But a single crumb of raw beef can carry enough
E. coli
O157:H7 to start a dangerous infection.
Vegetarians are not safe either. Cows shed
E. coli
O157:H7 in their manure, and once on the ground the microbe can survive for months. On farms the bacteria can spread from manure to crops, possibly carried by slugs and earthworms or ferried by irrigation. In 1997, radish sprouts tainted with O157:H7 sickened 12,000 people in Japan, killing 3. Today in the United States the vegetable-growing business is almost as industrialized as the beef business, with a few massive companies supplying produce across much of the country. They are also extending the reach of
E. coli
O157:H7. In September 2006, contaminated spinach from a single farm made people sick across the country, striking 205 people in twenty-six states. Three months later, it was lettuce distributed to Taco Bell restaurants in five states, striking 71 people.
When
E. coli
O157:H7 first passes the lips of one of its human victims, it does not seem much different from a harmless strain. Only after it has drifted through the stomach and reached the large intestine does it begin to show its true colors.
E. coli
O157:H7 has an unusual ability to eavesdrop on us. The cells of the human intestines produce hormones, and the microbe has receptors that can grab them. The hormones
E. coli
that could cause diseases. Some strains attacked the large intestine. Others attacked the small intestine. Some lived harmlessly in the gut but could cause painful infections if they got into the bladder, sometimes creeping all the way up to the kidneys. Other strains cause lethal blood infections, and still others reach the brain and cause meningitis. The scale of their cruelty is hard to fathom.
Shigella
alone strikes 165 million people every year, killing 1.1 million of them. Most of the dead are children. I can only wonder what Theodor Escherich would have thought if he had discovered that many of the bacteria killing his young patients were actually his
Bacterium coli communis.
Although many strains of
E. coli
are deadly, one has earned more headlines in recent years than all the rest combined. It goes by the name of O157:H7, a code for the molecules on its surface.
E. coli
O157:H7 is the strain that makes petting zoos hot zones, that can turn spinach or hamburger into poison, that can cause organ failure and death. For all its notoriety, though, it’s relatively new to science.
In February and March 1982, 25 people in Medford, Oregon, developed cramps and bloody diarrhea. Doctors identified a strain of
E. coli
in some of the patients that had never been seen before. Three months later the same strain caused an outbreak in Traverse City, Michigan. The source of the bacteria proved to be undercooked hamburgers that the victims had eaten at McDonald’s restaurants. A pattern had emerged, and now scientists began to hunt for
E. coli
O157:H7 in samples of bacteria taken from patients in earlier years. Out of 3,000
E. coli
strains collected from American patients in previous years, 1 proved to be O157:H7. It came from a woman in California in 1975. Searches in Great Britain and Canada turned up 7 more cases, but none before 1975.
O157:H7 slipped back into obscurity for a decade. It emerged again in the mid-1990s in a series of outbreaks across the world. In 1993, an outbreak spread in undercooked restaurant hamburgers in Washington State sickened 732 people. Four of them died. Scientists found that cows, sheep, and other livestock can carry O157:H7 in their intestines without getting sick. An estimated 28 percent of cows in the United States carry O157:H7. It can move from animal to human through bad butchering. If a cow’s colon is nicked during slaughter, the bacteria can get mixed into the meat. As meat from many cows gets blended together,
E. coli
O157:H7 can spread through tons of beef. Most of the bacteria are killed off by cooking. But a single crumb of raw beef can carry enough
E. coli
O157:H7 to start a dangerous infection.
Vegetarians are not safe either. Cows shed
E. coli
O157:H7 in their manure, and once on the ground the microbe can survive for months. On farms the bacteria can spread from manure to crops, possibly carried by slugs and earthworms or ferried by irrigation. In 1997, radish sprouts tainted with O157:H7 sickened 12,000 people in Japan, killing 3. Today in the United States the vegetable-growing business is almost as industrialized as the beef business, with a few massive companies supplying produce across much of the country. They are also extending the reach of
E. coli
O157:H7. In September 2006, contaminated spinach from a single farm made people sick across the country, striking 205 people in twenty-six states. Three months later, it was lettuce distributed to Taco Bell restaurants in five states, striking 71 people.
When
E. coli
O157:H7 first passes the lips of one of its human victims, it does not seem much different from a harmless strain. Only after it has drifted through the stomach and reached the large intestine does it begin to show its true colors.
E. coli
O157:H7 has an unusual ability to eavesdrop on us. The cells of the human intestines produce hormones, and the microbe has receptors that can grab them. The hormones
Similar Books
