Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and 21% oxygen); facultatively anaerobic bacteria can grow in the presence or absence of air. Microaerophilic bacteria do not grow at all aerobically or grow poorly, but grow better under 10% carbon dioxide or anaerobically. Anaerobic bacteria can be divided into strict anaerobes that can not grow in the presence of more than 0.5% oxygen and moderate anaerobic bacteria that are able of growing between 2 and 8% oxygen.[1] Anaerobic bacteria usually do not possess catalase, but some can generate superoxide dismutase which protects them from oxygen.
The clinically important anaerobes in decreasing frequency are:[2]
1. Six genera of Gram-negative rods (Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Bilophila and Sutterella spp.);
2. Gram-positive cocci (primarily Peptostreptococcus spp.);
3. Gram-positive spore-forming (Clostridium spp.) and non-spore-forming bacilli (Actinomyces, Propionibacterium, Eubacterium, Lactobacillus and Bifidobacterium spp.); and
4. Gram-negative cocci (mainly Veillonella spp.) .
The frequency of isolation of anaerobic bacterial strains varies in different infectious sites.[3] Mixed infections caused by numerous aerobic and anaerobic bacteria are often observed in clinical situations.
Anaerobic bacteria are a common cause of infections, some of which can be serious and life-threatening. Because anaerobes are the predominant components of the normal flora of the skin and mucous membranes, they are a common cause of infections of endogenous origin.[4] Because of their fastidious nature, anaerobes are hard to culture and isolate and are often not recovered from infected sites. The administration of delayed or inappropriate therapy against these organisms may lead to failures in eradication of these infections. The isolation of anaerobic bacteria requires adequate methods for collection, transportation and cultivation of clinical specimens.[2] The management of anaerobic infection is often difficult because of the slow growth of anaerobic organisms, which can delay their identification by the frequent polymicrobial nature of these infections and by the increasing resistance of anaerobic bacteria to antimicrobials.[1]
Anaerobicinfections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and...
necrotizing soft tissue infections. They participate in mixed anaerobicinfections, a term which is used to describe infections that are caused by multiple...
An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen...
anaerobes. The ability of facultative anaerobic pathogens to survive without oxygen is important since their infection is shown to reduce oxygen levels in...
Propionibacterium propionicus. The condition is likely to be a polymicrobial anaerobicinfection. The disease is characterised by the formation of painful abscesses...
from an infection. Infections can be caused by a wide range of pathogens, most prominently bacteria and viruses. Hosts can fight infections using their...
in which an excessive growth of Gardnerella vaginalis and other mostly anaerobic bacteria displace the beneficial Lactobacilli species that maintain healthy...
infections in reptiles and amphibians. In general, the veterinary community may use metronidazole for any potentially susceptible anaerobicinfection...
pus, which is described as looking like "anchovy paste". Pus from anaerobicinfections can more often have a foul odor. In almost all cases when there is...
gut microbiota and are often recovered from anaerobicinfections of the respiratory tract. These infections include aspiration pneumonia, lung abscess...
microaerophiles, and aerotolerant organisms. For example, obligately anaerobic Clostridium species will be seen growing only in the bottom of the test...
specific to muscle tissue. It is often seen in infections with C. perfringens or any of myriad soil-borne anaerobic bacteria. Bacteria cause myonecrosis by specific...
perfringens can participate in polymicrobial anaerobicinfections. It is commonly encountered in infections as a component of the normal flora. In this...
only species in its genus, and is a common constituent of mixed anaerobicinfections such as intra-abdominal abscess. It has rarely been implicated as...
direct or indirect contact with their feces. Vaccines can prevent this infection, but mortality can reach 91% in untreated cases. Often, treatment involves...
Clostridioides difficile infection (CDI or C-diff), also known as Clostridium difficile infection, is a symptomatic infection due to the spore-forming...
infections are typically indolent (the infection does not become clinically evident until a week or more after the injury). They also mimic anaerobic...
vaginal microbiota, and are recovered from anaerobicinfections of the respiratory tract. These infections include aspiration pneumonia, lung abscess...
pathogens in nosocomial infections. It naturally occurs in the soil, and about 30% of strains can fix nitrogen in anaerobic conditions. As a free-living...
pathogen in various anaerobicinfections, often mixed with other aerobic and anaerobic bacteria. P. melaninogenica is an anaerobic, Gram-negative rod,...
aeruginosa is a common encapsulated, Gram-negative, aerobic–facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including...
Trichomonas vaginalis is an anaerobic, flagellated protozoan parasite and the causative agent of a sexually transmitted disease called trichomoniasis...
it is available, or using other electron acceptors or fermentation ("anaerobically") when oxygen is not available. Salmonella species are intracellular...
fragilis is involved in 90% of anaerobic peritoneal infections. It also causes bacteremia associated with intra-abdominal infections, peritonitis and abscesses...
Cellulitis is usually a bacterial infection involving the inner layers of the skin. It specifically affects the dermis and subcutaneous fat. Signs and...
Fusobacterium is a genus of obligate anaerobic, Gram-negative, non-sporeforming bacteria belonging to Gracilicutes. Individual cells are slender, rod-shaped...
Necrotizing fasciitis (NF), also known as flesh-eating disease, is a bacterial infection that results in the death of parts of the body's soft tissue. It is a...
Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates causing amoebiasis...
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