Top 10 FAQs about E. Coli Bacteria released by Academy of Microbiology

E.coli: What you should know from American Academy of Microbiology

What you need to know about E. coli

The American Academy of Microbiology has recently released a top 10 FAQs list answering common questions people have about E. coli bacteria.

The FAQ list is the brainchild of an expert panel of microbiologists, bacteriologists and food safety professionals who wanted to bring to the public an informative and easily understandable life story of bacteria as a big picture of how E. coli bacteria plays an important role in health, food and our own biology.

The E. coli (Escherichia coli) bacterium is a single celled prokaryotic organism. A prokaryote basically is a more primitive form in comparison to the cells that make up the tissues in our body that are called eukaryotic cells. Both cell types differ in cellular membranes, nuclear (DNA) material and some biochemical processes.

Yeast used to ferment wine and raise bread is an example of a single cell eukaryotic organism. Past speculation proposes that some prokaryotic cells evolved into eukaryotic cells by ingesting other types of cells and integrating their features.

The “E.” in E. coli is named after the bacterium’s discoverer in 1885, the German scientist Theodor Escherich. The “coli” in E. coli comes from the meaning “in the colon,” from which many types of E. coli permanently reside from our birth to our death.

E. coli plays both a beneficial and deadly role in human health and as such, is often misunderstood by the public when a news story comes out about some recent discovery or precaution involving bacteria.

Because of this, a panel of experts from the American Academy of Microbiology has put together a list of frequently asked questions and their answers to help the public understand the lowly bacteria a little better.

Below is a summary of the top 10 FAQ’s about E. coli bacteria:

1. How has E. coli contributed to our understanding of biology?

E. coli is known as a model organism for scientific study because it possesses shared biochemical processes that would be difficult and ethically impossible to study directly using humans as an experimental subject. Examples of contributions made through studying E. coli include understanding DNA form and function, viral infection and replication, and the development of medicines.

One example of an important medicine resulting from E. coli is insulin. At one time, insulin had to be isolated from the pancreas of a pig for treating humans for diabetes. Today, insulin in manufactured by inserting an insulin gene inside the DNA of a bacterium, which when grown in a special media releases safe, effective and inexpensive insulin for diabetic patients.

2. What does the naturally occurring E. coli in our GI tract do?

E. coli is one of many types of microbes that live in your gut. In fact, the microbes in your digestive tract outnumber all other cells combined in the human body by 10:1. These microbes play an important role in digesting food and processing nutrients that nourish the rest of the body. Although E. coli is a minority organism among the various gut microbes, it plays a very important role in making the gut habitable for the beneficial microbes. Without bacteria in our gut, our health would be in dire straits very quickly.

3. What is the difference between “good” E. coli that inhabits our gut, and “bad” E. coli that makes us sick?

The basic difference between good E. coli and bad E. coli is that the bad E. coli includes some DNA that encodes for proteins that can be harmful to our cells. Bad bacteria can and do live in our digestive tracts, but are relatively harmless as our guts have adapted to handle the bad bacteria.


However, if the bad bacteria make it from our digestive tract to our uro-genital system, it can cause a serious infection because the uro-genital system is not immune to the bad bacteria. This is one reason why anal sex often leads to serious infections.

4. How do pathogenic E. coli make us sick?

One way pathogenic E. coli can make us sick is through the release of toxins by the bacterium. The toxins released are proteins that have an adverse effect on cells that it may come in contact with within the digestive tract.

The results of some of these toxins may be limited to stomach cramping and diarrhea. However, in more serious cases the toxins can enter the bloodstream and result in organ damage and toxic shock.

5. Why does E. coli make some people sick and not others?

Basically, one answer is that it has to do with a person’s immune system. A healthy immune system can fight off a bacterial infection with no problem; however, if the immune system is compromised such as with HIV, diabetes and some cancers, the immune system is too weak to handle the added burden of a bacterial infection.

6. How does E. coli become pathogenic?

E. coli is often referred to as being sexually promiscuous. What this means is that some E. coli in the presence of other bacteria will exchange DNA through a “sex pili” that connects the two bacterium to each other. When a safe E. coli bacterium takes in some DNA from a non-safe bacterium it will sometimes integrate the harmful DNA into its own genome and be transformed into a pathogenic bacterium.

7. How do E. coli get genes from other bacteria?

One way that E. coli get genes from other bacteria is indirectly through viruses. How it works is that a virus may infect one bacterium, make copies of itself in the bacterial cell, and then lyse into many progeny viruses.

Sometimes, however, the progeny viruses will pick up some of the DNA from the infected bacterium and then can pass it onto other bacteria that later become infected by the progeny viruses.

8. How does our food become contaminated with E. coli?

Food contamination by E. coli can occur by multiple routes: Using manure for fertilizer, exposure to wild animal droppings from rats and mice carrying disease, using contaminated water for feeding crops and for washing foods, and poor processing methods and unsanitary equipment are just a few of the many ways that E. coli contamination occurs.

9. What steps are being taken to protect our food from contamination by pathogenic E. coli ? And what can be done?
Two ways to protect food from contamination from pathogenic E. coli are to prevent bacteria from getting into food in the first place and to treat all food products with practices that kill or inactivate any bacteria that may have gotten past the growers and the sellers.

10. What types of foods are most commonly associated with E. coli, and why do there seem to be more cases of contamination recently?

The foods that are most likely to come into contact with animal or human fecal waste are the ones most likely to become contaminated with E. coli—especially if they are not properly cooked, including beef, sprouts, raw cookie dough, raw nuts, raw milk cheeses, and raw fruits and vegetables.

Source: A report from the American Academy of Microbiology

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