肠道正常菌群肠外机会致病 肠道壁物理损伤(肠道炎症、肿瘤,腹腔手术、 结肠镜检查.) 口肠道菌逸出(混合感染),异位定植于腹腔等处 炎症反应导致脓肿( absces形成 口脓肿增大可致肠梗阻,侵蚀血管可产瘘 口脓肿破裂可导致菌血症,感染扩散 腹腔脓肿中B. fragilis分离率可高达80%
肠道正常菌群肠外机会致病 6 肠道壁物理损伤（肠道炎症、肿瘤，腹腔手术、 结肠镜检查…） 肠道菌逸出（混合感染），异位定植于腹腔等处 炎症反应导致脓肿 (abscess) 形成 脓肿增大可致肠梗阻，侵蚀血管可产瘘 脓肿破裂可导致菌血症，感染扩散 腹腔脓肿中B. fragilis分离率可高达80%
Bacteroides fragilis 口概述 口生物学特性与疾病相关性 口健康相关性 口文献报告
Bacteroides fragilis 7 概述 生物学特性与疾病相关性 健康相关性 文献报告
B. fragilis特殊生物学性状 Aerotolerance耐氧 Spingolipid synthesis鞘脂合成 Low endotoxity LPS低内毒素活性脂多糖 Zwitterionic polysacchride capsule两性离子多糖 荚膜 ·BFT外毒素 · Antibiotic resistance抗生素抗性 口拟杆菌属其它种亦可能具备某些上述性状
B. fragilis 特殊生物学性状 8 • Aerotolerance 耐氧 • Spingolipid synthesis 鞘脂合成 • Low endotoxity LPS 低内毒素活性脂多糖 • Zwitterionic polysacchride capsule 两性离子多糖 荚膜 • BFT 外毒素 • Antibiotic resistance 抗生素抗性 拟杆菌属其它种亦可能具备某些上述性状
细菌与氧 Aerobes and anaerobes Oxygen requirement: terminal oxidase High-affinity oxidase: microxic/anoxic respiration Low-affinity oxidase: oXic respiration Oxygen tolerance: reactive oxygen species(ROs) ROs:O2+e→O2 SoD:22+2H→>H2O2+O2, Catalase:2H2O2→ 2H20+O2 ROs> DNA and protein damage repair
细菌与氧 9 • Aerobes and anaerobes • Oxygen requirement: terminal oxidase • High-affinity oxidase: microxic/nanoxic respiration • Low-affinity oxidase: oxic respiration • Oxygen tolerance: reactive oxygen species (ROS) • ROS: O2 + e O2 -… • SOD: 2O2 - + 2H+ H2O2 + O2 , Catalase: 2H2O2 2H2O + O2 • ROS DNA and protein damage repair
细菌与氧 Organisms Aerobic Low-affinity Microaerobic High-affinity ROs Anaerobic Representative species growth growth oxIdase defence growth Obligate aerobes Mycobacterium leprae Microaerophiles Helicobacter pylori Facultative anaerobes*+ Escherichia coli Anaerobes Bacteroides fragilis Aerotolerant anaerobes Streptococcus pneumoniae ligate anaerobes Clostridium tetani ROS, reactive oxygen species. Not all facultative anaerobes have high-affinity oxidases or grow microaerobically. Many obligate anaerobes tolerate transient or low levels of o Morris, R. L and T M. Schmidt (2013). Nat Rev Microbiol 11(3): 205-212
细菌与氧 10 Morris, R. L. and T. M. Schmidt (2013). Nat Rev Microbiol 11(3): 205-212