A photomicrograph of Escherichia coli, (Bacillus coli), bacteria using Gram-stain technique.
These are colonies of Escherichia coli bacteria grown on a Hektoen enteric (HE) agar plate medium; colonies of E. coli grown on HE agar display a raised morphology, and are yellow, to orange-yellow in coloration.HE agar is the medium designed for the isolation, and recovery of fecal bacteria belonging to the family Enterbacteriaceae. Escherichia coli is the most common aerobic bacteria found in the large intestine of healthy individuals, and accounts for 90-95% of all the aerobic bacteria. When E. coli is present in the diarrheal stools of infected persons, they can be passed from one person to another if hygiene, or hand-washing habits are inadequate.Escherichia coli Infections
Escherichia coli
Many non-pathogenic strains of E.coli are a normal part of the intestinal flora. E. coli O157:H7 is one of hundreds of strains of the bacterium Escherichia coli. Although most strains are harmless, this strain produces a powerful toxin that can cause severe illness. E. coli O157:H7 has been found in the intestines of healthy cattle, deer, goats, and sheep.
E. coli O157:H7 was first recognized as a cause of illness in 1982 during an outbreak of severe bloody diarrhea; the outbreak was traced to contaminated hamburgers. Since then, more infections in the United States have been caused by eating undercooked ground beef than by any other food. The combination of letters and numbers in the name of the bacterium refers to the specific markers found on its surface and distinguishes it from other types of E. coli.
People generally become ill with intestinal infections caused by from E. coli O157:H7 two to eight days (average of 3-4) after being exposed to the bacteria. E. coli O157:H7 infection often causes severe bloody diarrhea and abdominal cramps. Sometimes the infection causes non-bloody diarrhea or no symptoms. Usually little or no fever is present, and the illness resolves in 5 to 10 days.
In some persons, particularly children under 5 years of age and the elderly, the infection can also cause a complication called hemolytic uremic syndrome (HUS), in which the red blood cells are destroyed and the kidneys fail. About 8% of persons whose diarrheal illness is severe enough that they seek medical care develop this complication. In the United States, HUS is the principal cause of acute kidney failure in children, and most cases of HUS are caused by E. coli O157:H7.
According to the Centers for Disease Control: most people recover without antibiotics or other specific treatment within 5 to 10 days. Antibiotics should not be used to treat this [intestinal] infection. There is no evidence that antibiotics improve the course of disease, and it is thought that treatment with some antibiotics could lead to kidney complications. Antidiarrheal agents, such as loperamide (Imodium®), should also be avoided.
In some people, E. coli O157:H7 infection can cause a complication called hemolytic uremic syndrome (HUS), a life-threatening condition that is usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required. With intensive care, the death rate for hemolytic uremic syndrome is 3%-5%.
E.coli's Role in Urinary Tract Infections
The CDC reports that urinary track infections (UTIs), which in the United States account for about 4 million ambulatory-care visits each year and represent about 1% of all outpatient visits, are usually caused by E.coli.
As reported in the San Jose Mercury News in October of 2001, a University of California-Berkeley study indicated:
Food contamination is believed to be the culprit behind an epidemic of painful urinary-tract infections that are resistant to conventional treatment, according to a startling new study by University of California-Berkeley scientists.
While the origins of this newly-identified "superbug" remain a mystery, scientists say they believe it was transmitted through food because it was found almost simultaneously on campuses as far away as Berkeley, Calif., Minneapolis and Ann Arbor, Mich. _ and looked genetically similar in each locale, suggesting it had just arrived and had not had time to evolve. "This became a rapidly emerging problem; it was not a gradual process," said epidemiologist Dr. Lee W. Riley of the UC-Berkeley School of Public Health. "The only way that could happen is through the introduction of some nationally-distributed food product.
The scientists found that 22 percent of urinary-tract infections at the campuses were resistant to a drug called trimethoprim-sulfamethoxazole (TMP-SMX), the first line of therapy, as well as other antibiotics. Of these drug-resistant infections, half were caused by a previously unrecognized strain of bacteria.
For the past decade, doctors have been warning that diseases that were once easily cured are now stronger than their medicines. Drug-resistant bacteria are typically created through the excessive use of antibiotics. These bacteria are usually spread in hospital settings.
The current outbreak, another unsettling example of the resistance trend, is especially worrisome if resistance was acquired by simply eating food that had been contaminated by the superbug.
In an editorial that accompanied the study, Dr. Walter E. Stamm of the University of Washington School of Medicine in Seattle, urged "a much more aggressive approach to the control of anti-microbial resistance."
"The emergence and spread of resistance among E. coli that cause urinary-tract infections represent yet another example of the ongoing global problem of anti-microbial resistance," he wrote.
