|
Anaerobic infections are caused by anaerobic bacteria. Anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and 21% oxygen); facultative anaerobic bacteria can grow in the presence as well as in the 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 to 8% oxygen.〔Jousimies-Somer HR, Summanen P, Baron EJ, Citron DM, Wexler HM, Finegold SM. Wadsworth-KTL anaerobic bacteriology manual. 6th ed. Belmont, CA: Star Publishing, 2002.〕 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:〔Brook, I.: "Anaerobic Infections Diagnosis and Management". A Textbook. Informa Healthcare USA, Inc. New York. 2007.〕 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 nonspore-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.〔Nagy E. Anaerobic infections: update on treatment considerations. Drugs. 2010;70:841–58〕 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 skin's and mucous membranes normal flora, they are a common cause infections of endogenous origin.〔Hentges DJ. The anaerobic microflora of the human body . Clin Infect Dis 1993;164:S175–80.〕 Because of their fastidious nature, anaerobes are hard to 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.〔Brook, I.: "Anaerobic Infections Diagnosis and Management". A Textbook. Informa Healthcare USA, Inc. New York. 2007.〕 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.〔Jousimies-Somer HR, Summanen P, Baron EJ, Citron DM, Wexler HM, Finegold SM. Wadsworth-KTL anaerobic bacteriology manual. 6th ed. Belmont, CA: Star Publishing, 2002.〕 ==Signs and symptoms== Anaerobes have been found in infections throughout the human body.〔Nagy E. Anaerobic infections: update on treatment considerations.Drugs. 2010;70:841–58〕 The frequency of their recovery depends on the employment of proper methods of collection of specimen, their transportation to the microbiology laboratory and cultivation. The recovery of organisms depends on the site of infection and is related to the adjacent mucous membranes microbial flora. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「anaerobic infection」の詳細全文を読む スポンサード リンク
|