Jotwani R, Gupta U, Watanabe K, Ueno K
Department of Microbiology, All India Institute of Medical Sciences, New Delhi.
Microbiol Immunol. 1992;36(10):1041-9. doi: 10.1111/j.1348-0421.1992.tb02108.x.
Attempts were made to study the pathogenicity of some strains of Bacteroides fragilis group in the rat intra-abdominal abscess model. Multiple intraabdominal abscesses were produced in 50 to 70% of animals when an inoculum containing 10(9) CFU/ml of any of the five species of Bacteroides fragilis group was injected. Rising homologous antibody titers determined by indirect fluorescent antibody test were observed till the 3rd week when tested last, indirectly confirming the multiplication of the organisms as also evident by viable count of bacteria in the abscesses. In some cases in addition to inoculated organisms some intestinal bacteria like Escherichia coli, Proteus mirabilis and Streptococcus spp. were also recovered from the abscess pus. Studies with the electron microscope showed presence of capsular polysaccharide only in Bacteroides fragilis and Bacteroides thetaiotaomicron. It was doubtful in Bacteroides distasonis and absent in Bacteroides ovatus and Bacteroides vulgatus, suggesting that virulence factor beside the capsular polysaccharide may be playing a role. Further studies are required to investigate the virulence factor responsible for the pathogenicity of noncapsulated species.
研究人员尝试在大鼠腹腔脓肿模型中研究某些脆弱拟杆菌属菌株的致病性。当注射含有10(9) CFU/ml脆弱拟杆菌属五种菌株中任何一种的接种物时，50%至70%的动物会产生多个腹腔脓肿。通过间接荧光抗体试验测定的同源抗体滴度持续上升，直到最后一次检测的第3周，这间接证实了细菌的增殖，脓肿中细菌的活菌计数也证明了这一点。在某些情况下，除了接种的细菌外，脓肿脓液中还分离出一些肠道细菌，如大肠杆菌、奇异变形杆菌和链球菌属。电子显微镜研究表明，仅在脆弱拟杆菌和嗜内脏拟杆菌中存在荚膜多糖。在狄氏拟杆菌中情况存疑，而卵形拟杆菌和普通拟杆菌中则不存在，这表明除荚膜多糖外，毒力因子可能也在起作用。需要进一步研究来调查导致无荚膜菌株致病性的毒力因子。
