Anaerobic bacteria. Life without pure oxygen

Anaerobic bacteria are able to develop in the absence of free oxygen in the environment. Together with other microorganisms possessing such a unique property, they constitute a class of anaerobes. There are two types of anaerobes. Both facultative and obligate anaerobic bacteria can be found in virtually all samples of pathological material, they accompany various purulent-inflammatory diseases, can be opportunistic and even sometimes pathogenic.

Anaerobic microorganisms, related to facultative, exist and multiply in both oxygen and oxygen-free environments. The most pronounced representatives of this class are E. coli, Shigella, Staphylococcus, Yersinia, Streptococcus and other bacteria.

Obligate microorganisms can not exist in the presence of free oxygen and die from its effects. The first group of anaerobes of this class is represented by spore-forming bacteria, or clostridia, and the second by non-spore-forming bacteria (nonclostridial anaerobes). Clostridia are often the causative agents of anaerobic infections of the same name. An example may be clostridial wound infection, botulism, tetanus. Neclostrial anaerobes are Gram-positive and Gram-negative bacteria. They have a rod-shaped or spherical shape, for sure you have seen in the literature the names of their bright representatives: bacteroides, veyllonellas, fusobacteria, peptococci, propionibacteria, peptostreptococci, eubacteria, etc.

Neklostridialnye bacteria in their bulk are representatives of normal microflora in humans and animals. They can also participate in the development of purulent-inflammatory processes. These include: peritonitis, pneumonia, abscess of the lungs and brain, empyema of the pleura, sepsis, maxillofacial phlegmons, otitis, etc. For the bulk of infections that cause anaerobic bacteria of the non-clostridial type, it is characteristic to exhibit the properties of endogenous ones. They develop mainly against the background of a decrease in the resistance of the body, which can arise as a result of trauma, cooling, surgical intervention, immunity disorders.

To explain the way of maintaining the vital activity of anaerobes, it is worthwhile to understand the basic mechanisms by which aerobic and anaerobic breathing takes place.

Aerobic respiration is an oxidative process based on the use of oxygen. Breathing leads to the cleavage of the substrate without residue, the result is the inorganic representatives split into poor energy. As a result, there is a powerful output of energy. Carbohydrates are the most important substrates for respiration, but proteins and fats can be consumed in the process of aerobic respiration.

It corresponds to two stages of percolation. At the first stage, an oxygen-free process of gradual splitting of the substrate occurs for the release of hydrogen atoms and binding to coenzymes. The second, oxygen stage, is accompanied by the further splitting off of hydrogen atoms from the substrate for respiration and its gradual oxidation.

Anaerobic respiration uses anaerobic bacteria. They use for oxidation of the respiratory substrate not molecular oxygen, but a whole list of oxidized compounds. They can be salts of sulfuric, nitric, carbonic acids. During anaerobic respiration, they are converted to reduced compounds.

Anaerobic bacteria that carry out such a breath as the final electron acceptor use not oxygen, but an inorganic substance. By their belonging to a certain class, several types of anaerobic respiration are distinguished: nitrate respiration and nitrification, sulfate and sulfur respiration, "iron" respiration, carbonate respiration, fumarate respiration.