Anaerobic bacteria live without oxygen and can be found in the human body, soil, water, food, and animals. Some are beneficial, aiding in digestion or bioremediation, while others cause disease. There are three types of anaerobes: obligate, aerotolerant, and facultative. Anaerobic infections can occur in wounds, skin lesions, lungs, abdomen, and mouth. Symptoms vary depending on the location of the infection and risk factors include compromised immune systems, surgery, and injury. Anaerobes come in various shapes and can work together to cause infections.
Anaerobic bacteria, or anaerobes, are bacteria that don’t need oxygen to live. In humans, these bacteria generally live in the gastrointestinal tract, but can also be found in other places outside the body, including in soil and water, food and animals. Some anaerobes are beneficial to humans, but others can cause disease, such as appendicitis, diverticulitis and gingivitis. The hallmarks of an anaerobic bacterial infection are foul-smelling pus, abscess formation, and tissue destruction.
Beneficial or harmful
The genus Bacteroides is an example of beneficial and harmful anaerobic bacteria. In the gastrointestinal tract, species in this genus aid in digestion, but when found in other areas of the body, they can cause sinus thrombosis, pneumonia, and meningitis, among other diseases. Other anaerobes help people without living in their bodies. For example, some Lactobacillus species are commonly used in cheese making. Similarly, some types of Clostridium can be used in bioremediation, which is the process of making contaminated soil usable again; they do this by attacking contaminants and converting them into non-toxic carbon dioxide.
Types of anaerobes
There are three categories of anaerobic bacteria: obligate, aerotolerant and facultative. Obligate anaerobes need an oxygen-free environment to live. They cannot grow in places with oxygen, which can sometimes damage and destroy them. Aerotolerant bacteria do not use oxygen to live, but can exist in its presence. Facultative anaerobes use fermentation to grow in places without oxygen, but use aerobic respiration in places with oxygen.
Porphyromonas gingivalis is an example of an obligate anaerobe. It is commonly found in the mouth, but is also thought to be linked to rheumatoid arthritis. A common example of aerotolerant anaerobic bacteria is Propionibacterium acnes. It normally exists on people’s skin and is a contributing factor to acne. In some cases, it enters the body and causes endocarditis, which is an inflammation of the lining of the heart.
Some species of the genus Staphylococcus are facultative and are a major cause of blood poisoning. One example is Staphylococcus aureus, which produces a range of infections from common skin problems such as acne, boils and impetigo to acute conditions such as meningitis, endocarditis and pneumonia. It also causes toxic shock syndrome (TSS). Another facultative anaerobe is Escherichia coli, which contains many beneficial and some harmful strains of bacteria, such as those that cause food poisoning.
Anaerobic infections
Many anaerobes infect open wounds, diabetic skin ulcers, bites and other skin lesions. Bacterioids are some of the most common anaerobic bacterial species in diabetic foot wounds. Often, anaerobes coexist with aerobic bacteria, which need oxygen to thrive. This is common in foot ulcers, making them more difficult to treat.
Other anaerobes, such as those of the Actinomyces genus, can cause dental infections inside the mouth. Injury to the mouth, surgery or disease can allow normally benign anaerobic bacteria to develop into infection, causing abscesses, pain and inflammation. Rinsing with hydrogen peroxide releases oxygen, which can help kill bacteria or slow their growth. Anaerobic mouth infections can also occur in the root canals, jaw, tonsils, and throat.
Sometimes anaerobes infect the lungs, causing abscesses, pneumonia, purulent pleurisy, and dilated lung bronchi. Other times they affect the abdomen, causing peritonitis and abscesses. Several species can be found throughout the body; for example, species of the Actinomyces genus usually appear in the oral cavity and upper respiratory tract but may exist in the gastrointestinal tract. Other species live in specific areas, such as the colon. Bacteroides species are typically found in human feces and cause tissue destruction when introduced into a wound.
Symptoms of infection
Symptoms of an anaerobic infection typically vary depending on its location, although pain and fever are quite common. For example, infections in the area of the teeth and gums often cause pain, swelling and bleeding in the gums, as well as bad breath. In severe cases, a person may get oozing sores or large holes in the gums.
A person with a throat infection may have a sore throat, choking sensation, or fever, along with bad breath. People with lung infections may have difficulty breathing, as well as cough, chest pain, and fever. Those with abdominal infections may experience fever and pain. If a person has recently had surgery, there may be foul-smelling drainage from their wound. Pelvic infections usually cause pain, fever, chills, and drainage from the uterus.
Anaerobic bacterial infections in skin wounds usually appear as red, swollen areas and may secrete foul-smelling pus. Bloodstream infections often cause chills and a high fever and can ultimately lead to death. People with blood poisoning usually have red streaks on the skin near the wound, even if the wound doesn’t appear to be infected.
Risk factors
There is an increased risk of infection in those who have compromised immune systems, have had surgery, or have suffered an injury. People with diabetes mellitus, blood vessel disease, cancer and tumors are also more prone to bacterial infections.
It is sometimes difficult to know where a person has contracted a bacterial-based disease. For example, the spores of Clostridium bacteria, which can cause tetanus, botulism and gas gangrene, can live in harsh conditions for a long time before germinating and growing. Many cases of infection are caused by different types of anaerobic bacteria working together.
Common shapes
Anaerobes come in many forms. Actinomyces have rod shapes that can be straight, slightly curved, or branched. Propionibacterium also comes in different shapes, such as oval, club-shaped or rod-shaped, as well as branched and forked. Doctors and researchers use shape as one of the identifying factors when diagnosing a patient or studying a bacterium.
Protect your devices with Threat Protection by NordVPN
