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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.
Examples of obligately anaerobic bacterial genera include Actinomyces, Bacteroides, Clostridium, Fusobacterium, Peptostreptococcus, Porphyromonas, Prevotella, Propionibacterium, and Veillonella. Clostridium species are endospore-forming bacteria, and can survive in atmospheric concentrations of oxygen in this dormant form. The remaining ...
Anaerobic bacteria and archaea use these and many other fermentative pathways, e.g., propionic acid fermentation, [14] butyric acid fermentation, [15] solvent fermentation, mixed acid fermentation, butanediol fermentation, Stickland fermentation, acetogenesis, or methanogenesis.
Bacterial pathogens often cause infection in specific areas of the body. Others are generalists. Bacterial vaginosis is a condition of the vaginal microbiota in which an excessive growth of Gardnerella vaginalis and other mostly anaerobic bacteria displace the beneficial Lactobacilli species that maintain healthy vaginal microbial populations. [13]
Aerobic bacteria require air to survive, while anaerobic bacteria die in contact with oxygen. This makes anaerobic bacteria more challenging to culture and, therefore, study.
Large quantities of fecal coliform bacteria in water are not harmful according to some authorities, but may indicate a higher risk of pathogens being present in the water. [3] Some waterborne pathogenic diseases that may coincide with fecal coliform contamination include ear infections, dysentery , typhoid fever , viral and bacterial ...
As microorganisms, in particular bacteria, are found virtually everywhere, harmful microorganisms may be reduced to acceptable levels rather than actually eliminated. In food preparation, microorganisms are reduced by preservation methods such as cooking, cleanliness of utensils, short storage periods, or by low temperatures.
Bacteroides fragilis is an anaerobic, Gram-negative, pleomorphic to rod-shaped bacterium. It is part of the normal microbiota of the human colon and is generally commensal , [ 1 ] [ 2 ] but can cause infection if displaced into the bloodstream or surrounding tissue following surgery, disease, or trauma.