In our organism, we have many bacteria and there are more bacterial cells than humans. The set of bacteria that inhabit our intestines is called intestinal flora composed of a large number of bacteria about 100 billion. The predominant ones are of the family such as Escherichia coli. Most bacteria in our body are harmless and beneficial because of the protective effect of the immune system. Therefore, the intestinal flora is very important for the state of health of the organism. However, some can cause infections of various gravitates for which antibiotics are used.

intestinal bacteria

Bacterial flora

The bacterial flora acts as a defense of our organism and protects us against possible diarrhea caused by antibiotics besides helping us with some diseases. It also helps our digestive system to function properly helps in the production of some vitamins such as B and K and facilitates the proper absorption of minerals such as calcium iron and magnesium.

The intestinal flora can be altered by changes such as age antibiotics or unhealthy habits causing gas, diarrhea or some infections. It can be reestablished by an adequate diet or by taking probiotics, which are live microorganisms, administered in adequate quantities our intestinal flora. In our intestinal flora, we can find several families or groups of bacteria among which are the enterobacteria, which are the most abundant lactobacilli. Bacteria are divided into two large groups and Gram staining is used to differentiate them.

Gram staining is used in bacteriology to visualize bacteria in clinical specimens. When the bacteria are stained purple or dark blue they are Gram positive and the negative ones, for their part, are stained pink or red. This serves to differentiate them in the first instance. There are some bacteria that have the ability to change and are called Gram variables, but they are neither better nor worse. Next, let us look at some of the bacteria that reside in our intestinal flora.

Escherichia coli

The Escherichia coli is the most common family of enterobacteria which are the most abundant of our intestinal flora located in the gastrointestinal tract. Although their presence in the body is normal, and even necessary for the functioning of the digestive process, they can sometimes become pathogenic and appear infections. If introduced by food can cause intestinal problems as it crosses the gastrointestinal mucosa and can cause diarrhea and dehydration.


It is the species of greater clinical relevance that is composed by Gram-negative bacteria of the enterobacteria, like the Escherichia Coli. The bacteria Klebsiella are naturally present in the digestive tract, but its action is well controlled by the body so there is usually no risk of infection. There is more quantity when the person is in a hospital or their defenses are very low and there is facility to get infections. This bacteria has no immune response, its defenses are diminished.


Streptococci or Streptococcus is a group of bacteria consisting of spherical bacteria that are gram positive and belong to the group of lactic acid bacteria. There are several classified groups of streptococci, the A, B, C. Groups C and G, are less pathogenic. These are enterococci that are sometimes found in the gastrointestinal tract and although they are less pathogenic, they can produce gastrointestinal problems that can be confused with pharyngitis.