科学家发现在胆囊中形成的鹅卵石形状的胆结石可能让伤寒逃过身体的防御，并且让这种疾病对临床治疗产生抵抗。John Gunn及其同事报告说，感染后伤寒引发的沙门氏菌可能在基于胆固醇的胆结石上形成持久的细菌群落或者说生物膜。
这组科学家发现，被注射了一种啮齿类伤寒热并摄取高胆固醇饮食的小鼠在胆结石上形成了生物膜，并且比没有胆结石的小鼠在胆囊组织、胆汁和粪便中含有更多的细菌。这组作者还测试了无临床症状携带伤寒的人类患者切除的胆结石，并在除了一个样本之外的所有样本中观察到了伤寒沙门氏菌生物膜。在有伤寒沙门氏菌和胆结石的患者中，临床使用抗生素通常被证明无法消除这种感染，而切除胆结石仍然是成功的治疗选项。这组科学家提出，在胆结石上形成的伤寒沙门氏菌生物膜可能有助于解释这种疾病甚至在没有急性症状的情况下的持久性和传播。这组作者说，这项研究可能促进对活体伤寒携带者的调查，而且可能帮助科研人员寻找人类传播伤寒热的治疗目标。
原始出处：
PNAS February 22, 2010, doi: 10.1073/pnas.1000862107
Gallstones play a significant role in Salmonella spp. gallbladder colonization and carriage
Robert W. Crawforda, Roberto Rosales-Reyesb, María de la Luz Ramírez-Aguilarb, Oscar Chapa-Azuelac, Celia Alpuche-Arandad, and John S. Gunna,1
aCenter for Microbial Interface Biology and Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210;
bDepartamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico D.F., Mexico;
cDepartamento de Cirugía, Hospital General de México, Mexico, D.F., Mexico; and
dDirección General Adjunta, Instituto Nacional de Referencia Epidemiológica, Mexico D.F., Mexico
Salmonella enterica serovar Typhi can colonize the gallbladder and persist in an asymptomatic carrier state that is frequently associated with the presence of gallstones. We have shown that salmonellae form bile-mediated biofilms on human gallstones and cholesterol-coated surfaces in vitro. Here, we test the hypothesis that biofilms on cholesterol gallbladder stones facilitate typhoid carriage in mice and men. Naturally resistant (Nramp1+/+) mice fed a lithogenic diet developed cholesterol gallstones that supported biofilm formation during persistent serovar Typhimurium infection and, as a result, demonstrated enhanced fecal shedding and enhanced colonization of gallbladder tissue and bile. In typhoid endemic Mexico City, 5% of enrolled cholelithiasis patients carried serovar Typhi, and bacterial biofilms could be visualized on gallstones from these carriers whereas significant biofilms were not detected on gallstones from Escherichia coli infected gallbladders. These findings offer direct evidence that gallstone biofilms occur in humans and mice, which facilitate gallbladder colonization and shedding.
