Here is a recent news headline: E coli closes a local beach. As you probably know, E. coli, or Escherichia coli as it is named by genus and species, is a bacteria. Bacteria are simple single-celled creatures, a step down from amoebas. Unlike viruses, they can reproduce on their own (by splitting) and have a metabolism. This means they take in food and produce wastes. The waste can be beneficial or harmful. E. coli grows easily in air or without it. It isn’t picky about its temperature for growth although it prefers near body temperature. It’s found in the intestines of animals and different animals contain different strains.
Microbiologist Lee Macomber points out that a high E. coli count in water means that the water is contaminated with fecal matter. E. coli is easy to grow in the lab and it is an indicator of water cleanliness. E. coli serves as the bellwether species. There very well could be more dangerous bacteria including gastroenteritis and viruses such as Hepatitis A in contaminated water.
According to the Iowa DNR, fecal contamination of beach water occurs due to improperly constructed and operated septic systems and sewage treatment plants, manure spills, storm water runoff from lands with wildlife and pet droppings, or direct contamination from waterfowl, livestock, or small children in the water. In Iowa, rain appears to be one of the most important factors in generating high levels of bacteria. Surface runoff after a heavy rainfall may transport high levels of fecal bacteria to the water at the beach. The rain also increases the sediment in the water causing it to be murky. Since bacteria are destroyed by sunlight, murky water aids in their survival.
About half of Iowa’s water is impaired and less than a quarter is considered clean. Our current governor is planning to clean up the water–by making it more difficult to call a water impaired!
E. coli is a contaminant in water but is it all bad? It’s needed in our intestines. The bacteria produces Vitamin K and helps break down food for digestion. But it can turn up in the wrong places and some strains take a deadly turn. The most notorious strain is E. coli O157:H7–which is found in the digestive tract of healthy cattle. This bacteria produces Shiga toxin and other by-products that make people violently ill with diarrhea that is at its worst “all blood, no stool.” E. coli can infect meat when slaughtering is done carelessly. It can get into milk from animals and via dirt, animal bedding, and possibly by wind-borne dust. It is more puzzling how it gets into lettuce but animal and bird droppings, dust from nearby slaughterhouses and feed lots, and contamination from wild animals have all been cited as causes. E.coli clings to greens effectively and is hard to wash off. It can spread from person to person via poor hygiene. My students found E coli in ice from a soda dispenser once. It had to have gotten there from a worker’s dirty hands,
People with Type A blood are the most susceptible to E. coli related infections. The most common food source is ground beef. The most likely place to get an infection is in a developing nation and children under two are most vulnerable. Believe it or not, a large mussel population in a lake can filter E. coli from the water so the Great Lakes, especially Michigan, are rarely contaminated.
E. coli infection has been in the headlines lately. It’s been a contaminant of romaine lettuce since the start of the year and has shut down daycare centers and sickened kids in Tennessee. The most commonly affected foods are ground beef and other meats, green leafy vegetables, unpasteurized juices, raw milk, and soft cheeses made from raw milk. Symptoms include severe stomach cramps, diarrhea (often bloody), and vomiting. Hemolytic-uremic syndrome can cause kidney damage as well as death. E. coli can be blamed for most UTI infections, traveler’s diarrhea, and neonatal bacterial meningitis. If you have E.coli poisoning, staying hydrated is a way to dilute the toxins. Antibiotics, sometimes a cocktail of them, could be needed to rid yourself of the bacteria.
Four out of every 100,000 children in the US will be hospitalized for an E. coli related illness this year. E coli infections spike between June and September.
Here are ways to minimize the risk of an E. coli infection at home.
- Cook meat completely. E. coli is killed by proper heating.
- Thaw meat separately from other foods
- Use a different plate for raw vs cooked meat when cooking and grilling
- Wash food preparation surfaces and utensils
- Clean your refrigerator weekly
- Wash faucets and soap pumps daily. (Pump soap is more germy than bar soap.)
- Wash dish towels daily
- Promptly refrigerate perishable foods
- Make sure your refrigerator keeps a temperature of 35-38 degrees Fahrenheit.
- Wash your hands before and after preparing food.
Scientists are developing an E. coli vaccine but until that time, I’m keeping my kitchen clean and staying out of the local water.
However, frightening it can be, E. coli is beneficial to medicine and makes many drugs more affordable. E. coli is easy to grow and is genetically simple. It has one large chromosome in the shape of a ring. It is the microorganism of choice for cloning. The chromosome can be modified to change the bacterial waste products. It can be altered to produce insulin for example. In this case, the gene that made human insulin was cut from a human cell and inserted into the bacteria. Click here to see the process in pictures. It can be used to produce human growth hormone by inserting a different gene. Erythromycin and other drugs are made this way. It can even produce by-products that can be made into plastic, should we need more plastic.
Did to recognize the E. coli? It’s the hairy yellow critter left of center in the photo up top.