BACKGROUND Some strains of Bacteroides fragilis species are associated with diarrhea as a result of enterotoxin production (bft or fragilysin). Fragilysin is activated by C11 protease (fpn) and together with C10 protease (bfp) play a significant role in its invasiveness. The objectives of this study were to investigate the proportion of clinical isolates from extra-intestinal sources that are toxin producers and characterize the genes mediating toxin production. Clinical isolates submitted to our reference laboratory over the last 13 years were screened for toxin production using PCR technique. All stool isolates were excluded. The isolates were tested for their susceptibility to 8 antimicrobial agents by E test. Carbapenem resistance gene cfiA was detected by PCR. RESULTS A total of 421 B. fragilis isolates were viable. Out of these, bft was detected in 210 (49.9%) isolates. Of the 210 bft-positive isolates, 171 (81.4%), 33 (15.7%) and 6 (2.8%) harbored bft-1, bft-2, and bft-3 genes, respectively. Twenty (9.5%) of the bft-positive strains originated from bloodstream infections. Twenty-five, 20 and 9 strains harbored bfp-1, bfp-2 and bfp-3 gene, respectively. Two, 3, 4 bfp isotypes were detected simultaneously in some of strains. The resistance rates against amoxicillin-clavulanic acid was 32%, clindamycin 62%, cefoxitin 26%, imipenem 11%, meropenem 17%, metronidazole 4%, piperacillin 61% and tigecycline 14%. A chromosomally located cfiA gene that encode metallo-β-lactamase was identified in only 34 isolates (16.2%). CONCLUSIONS The prevalence of enterotoxin-producing B. fragilis was high among the extra-intestinal isolates. Metronidazole was the most active agent against all isolates. There was no statistically significance difference between resistance rates among bft-positive and bft-negative isolates except for clindamycin.

中文翻译：

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在科威特的13年分离株中，易产肠毒素的肠外拟杆菌（Bacteroides fragilis）的患病率和抗菌药敏性。

背景技术由于肠毒素的产生（bft或fragilysin），一些脆弱的拟杆菌属菌株与腹泻有关。Fragilysin被C11蛋白酶（fpn）激活，并与C10蛋白酶（bfp）一起在其侵袭性中发挥重要作用。这项研究的目的是调查来自肠外来源的毒素产生者临床分离株的比例，并表征介导毒素产生的基因。使用PCR技术筛选过去13年提交给我们参考实验室的临床分离株的毒素产生情况。排除所有粪便分离株。通过E检验测试分离物对8种抗菌剂的敏感性。通过PCR检测碳青霉烯抗性基因cfiA。结果共有421种脆弱的B. gilgilis菌株是可行的。在这些之中 在210个（49.9％）分离物中检测到bft。在210个bft阳性分离株中，分别包含bft-1，bft-2和bft-3基因的171个（81.4％），33个（15.7％）和6个（2.8％）。bft阳性菌株中有二十种（9.5％）来自血流感染。25、20和9个菌株分别携带bfp-1，bfp-2和bfp-3基因。在某些菌株中同时检测到两个，三个，四个bfp同种型。对阿莫西林-克拉维酸的耐药率分别为32％，克林霉素62％，头孢西丁26％，亚胺培南11％，美罗培南17％，甲硝唑4％，哌拉西林61％和替加环素14％。仅在34个分离株（16.2％）中发现了编码金属β-内酰胺酶的染色体定位cfiA基因。结论在肠外分离株中，产生肠毒素的脆弱脆弱芽孢杆菌较高。甲硝唑是对所有分离物最有效的药物。除克林霉素外，bft阳性和bft阴性分离株之间的耐药率之间无统计学意义差异。