micro bio terms

micro bio terms - Anerobes do not require oxygen for life...

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Anerobes – do not require oxygen for life and reproduction Obligate anerobes – grow only in absence of oxygen - Moderate – unable to multiply in more than 2 – 8% O 2 ; can tolerate for several hours while growing on a plate, but cannot multiply - Strict – unable to multiply more than 0.5% O 2 ; killed after short exposure to O 2 Aerotolerant – capable of growing in oxygen, but grow best at anaerobic environment Facultative anaerobes – do not require oxygen, but can use it if it is available Endogenous anaerobes – anaerobes that are members of the body’s indigenous microflora Exogenous anaerobes – those that live in the external environment Heavy colonization of surfaces are the usual port of entry into tissues and bloodstream When access is gained to usually sterile site – result is serious or fatal infections Most are gram negative bacilli and anaerobic cocci Two common types of anaerobes in respiratory tract are Porphyromonas and Fusobacterium nucleatum Certain oral anaerobes produce volatile and foul-smelling metabolic by-products that contribute to “bad breath” Anaerobes of the skin: Members include: Propionibacterium acnes -Frequently isolated from blood cultures, and Indicates contamination or infection Anaerobes of the Genitourinary Tract: Anaerobes colonize the urethra and vagina area It is impossible to distinguish normal flora from those that cause infection Swabs and urine samples are NOT acceptable for anaerobic workups Anaerobes of the Gastrointestinal Tract: GI tract – plentiful with anaerobes Bacteroides fragilis - Most common anaerobe implicated in infections
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Other species include B vulgates, B thetaiotaomicron, B distasonis Other anaerobes Bifidobacterium, Clostridium, Eubacteria, Gram positive cocci Stool specimens are not routinely cultured for anaerobes However – if a patient is suspected of having psuedomembranous colitis and/or antiboitic associated diarrhea caused by C. difficile Stool should be tested for toxins produced by C. difficile Infectious disease Generally involves some type of trauma to skin or mucous membranes Allows entry of anaerobes into sterile tissues Vascular stasis (blocked blood flow) Prevents oxygen from entering environment or tissue necrosis may decrease the redox potential of the tissue Both make environment suitable for anaerobic growth
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micro bio terms - Anerobes do not require oxygen for life...

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