部分英文原文：

Nature Medicine，

Published online: 8 April 2007; | doi:10.1038/nm1572

Cyclic AMP–regulated exocytosis of Escherichia coli from infected bladder epithelial cells

Brian L Bishop1, Mathew J Duncan1, Jeongmin Song1, Guojie Li2, David Zaas3 & Soman N Abraham1, 2, 4

1  Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.

2  Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA.

3  Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.

4  Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA.

Correspondence should be addressed to Brian L Bishop blb7@duke.edu or Soman N Abraham soman.abraham@duke.edu

Abstract
The superficial bladder epithelium is a powerful barrier to urine and also serves as a regulator of bladder volume, which is achieved by apical exocytosis of specialized fusiform vesicles during distension of the bladder. We report that type 1 fimbriated uropathogenic Escherichia coli (UPEC) circumvents the bladder barrier by harboring in these Rab27b/CD63-positive and cAMP-regulatable fusiform vesicles within bladder epithelial cells (BECs). Incorporation of UPEC into BEC fusiform compartments enabled bacteria to escape elimination during voiding and to re-emerge in the urine as the bladder distended. Notably, treatment of UPEC-infected mice with a drug that increases intracellular cAMP and induces exocytosis of fusiform vesicles reduced the number of intracellular E. coli.