Bacteria can and their tolerance of O2 are classified according to their needs: Optional: Grow aerobically or anaerobically in the presence or absence of O2 Micro Aero Phil: You require a low O2 concentration (eg 5%) and, (for many, a high CO2 concentration, for example, 10%); grow very poorly anaerobic obligate anaerobic: Are not suitable for aerobic metabolic Sell, but unlike tolerant of O2 obligate anaerobes multiply in places with low oxidation-reduction potential (eg necrotic, devaskularisiertes fabric.). Oxygen is toxic to them. Obligate anaerobic bacteria have categorized based on their O2 tolerance; for a limited time tolerate tolerate atmospheric O2 The obligate anaerobes, which can often cause infection atmospheric O2 for at least 8 hours, often up to 72 h: compatibility Streng: Tolerance only ? 0.5% O2 Moderate: Tolerance 2 to 8% O2 aerotolerant anaerobic , Obligate anaerobes are key components of the normal microflora on the mucous membranes, especially the mouth, the lower GI tract, and vagina; these anaerobes cause disease when breaking the normal mucosal barriers. Gram-negative anaerobes and some of the infections that cause them, are Bacteroides (most common): Intra-abdominal infections Fusobacterium: abscesses, wound infections, lung and intracranial and infections Porphyromonas: aspiration pneumonia and periodontal disease Prevotella: Intra-abdominal and soft tissue infections Gram-positive anaerobic bacteria and some of the infections that they cause actinomycosis are: head, neck, abdominal and pelvic infections, and aspiration pneumonia (actinomycosis) clostridia: Intra-abdominal infections, for example, Clostridial necrotic enteritis), soft tissue infections and gas gangrene due to C. perfringens; Food poisoning due to C. perfringens type A; Botulism and infant botulism due to C. botulinum; Tetanus due C. tetani and C. difficile-induced diarrhea (pseudomembranous colitis Peptostreptococcus: oral, respiratory and intra-abdominal infections Propionibacterium. Foreign body infections (for example in a Liquorshunt, in joint prostheses or cardiac devices) Anaerobic infections typically extend purulent, . lead to the formation of abscesses and tissue necrosis and sometimes septic thrombophlebitis, gas formation, or both, many anaerobes form tissue-destroying enzymes and some of the most potent known neurotoxins Normally there are several types of anaerobic bacteria in infected tissues;. aerobes are often available (mixed anaerobic infections). evidence of anaerobic infections are polymicrobial results on Gram stain or culture gas into pus or infected tissues Putrid smell of pus or infected tissues Nekroti sch infected tissue site of infection near mucosa, where normally anaerobic microflora tests samples to test for anaerobes should be removed by aspiration or biopsy from normally sterile body sites. Samples should be taken to the laboratory as soon as possible, and the transport containers should -free an O2 prevents carbon dioxide, hydrogen and have nitrogenous atmosphere. Swabs are preferably in an anaerobic, sterile, semi-solid medium such. B. Cary-Blair transport medium transports.