Pantosti A, Cerquetti M, Colangeli R, D'Ambrosio F
Laboratory of Bacteriology and Medical Mycology, Istituto Superiore di Sanità, Rome, Italy.
J Med Microbiol. 1994 Sep;41(3):191-6. doi: 10.1099/00222615-41-3-191.
Bacteroides fragilis strains with enterotoxic activity can be isolated from the faeces of newborn farm animals with diarrhoea and are called enterotoxigenic B. fragilis (ETBF). These strains can now be detected in an in-vitro cytotoxicity assay with HT-29 cells. In this study, 146 B. fragilis strains (95 faecal and 40 extra-intestinal isolates) and 64 Bacteroides isolates belonging to species other than B. fragilis were tested for their ability to produce enterotoxin. Sixteen strains of ETBF were identified; all belonged to the fragilis species and represented 11% of all B. fragilis examined. The prevalence was similar among extraintestinal and faecal strains, 11.5% and 10%, respectively. The production of enterotoxin in clinical isolates appeared to be associated with infections where tissue destruction was more prominent. Enterotoxigenicity was not associated with the presence of a plasmid and the plasmid profiles of ETBF strains that harboured plasmids were different. These results show that enterotoxin production by human isolates of B. fragilis is not uncommon and could represent a new virulence factor of B. fragilis.
具有肠毒素活性的脆弱拟杆菌菌株可从患有腹泻的新生农场动物粪便中分离得到，被称为产肠毒素脆弱拟杆菌（ETBF）。现在可以通过HT - 29细胞的体外细胞毒性试验检测这些菌株。在本研究中，检测了146株脆弱拟杆菌菌株（95株粪便分离株和40株肠外分离株）以及64株不属于脆弱拟杆菌的拟杆菌属分离株产生肠毒素的能力。鉴定出16株ETBF菌株；它们均属于脆弱拟杆菌种，占所有检测的脆弱拟杆菌的11%。肠外菌株和粪便菌株中的患病率相似，分别为11.5%和10%。临床分离株中肠毒素的产生似乎与组织破坏更明显的感染有关。产肠毒素性与质粒的存在无关，携带质粒的ETBF菌株的质粒图谱也不同。这些结果表明，人源脆弱拟杆菌分离株产生肠毒素并不罕见，可能代表脆弱拟杆菌的一种新毒力因子。
