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Escherichia coli O157:H7 Curli Fimbriae Promotes Biofilm Formation, Epithelial Cell Invasion, and Persistence in Cattle
被引:17
作者:
Sheng, Haiqing
[1
]
Xue, Yansong
[1
]
Zhao, Wei
[1
]
Hovde, Carolyn J.
[1
]
Minnich, Scott A.
[1
]
机构:
[1] Univ Idaho, Bistate Sch Food Sci, Moscow, ID 83844 USA
基金:
美国国家卫生研究院;
关键词:
curli;
E;
coli O157;
biofilm;
invasion;
cattle;
SALMONELLA-TYPHIMURIUM;
GENOME SEQUENCE;
BINDING CURLI;
O157-H7;
STRAIN;
COLONIZATION;
PREVALENCE;
EXPRESSION;
PROTEIN;
K-12;
D O I:
10.3390/microorganisms8040580
中图分类号:
Q93 [微生物学];
学科分类号:
071005 ;
100705 ;
摘要:
Escherichia coli O157:H7 (O157) is noninvasive and a weak biofilm producer; however, a subset of O157 are exceptions. O157 ATCC 43895 forms biofilms and invades epithelial cells. Tn5 mutagenesis identified a mutation responsible for both phenotypes. The insertion mapped within the curli csgB fimbriae locus. Screening of O157 strains for biofilm formation and cell invasion identified a bovine and a clinical isolate with those characteristics. A single base pair A to T transversion, intergenic to the curli divergent operons csgDEFG and csgBAC, was present only in biofilm-producing and invasive strains. Using site-directed mutagenesis, this single base change was introduced into two curli-negative/noninvasive O157 strains and modified strains to form biofilms, produce curli, and gain invasive capability. Transmission electron microscopy (EM) and immuno-EM confirmed curli fibers. EM of bovine epithelial cells (MAC-T) co-cultured with curli-expressing O157 showed intracellular bacteria. The role of curli in O157 persistence in cattle was examined by challenging cattle with curli-positive and -negative O157 and comparing carriage. The duration of bovine colonization with the O157 curli-negative mutant was shorter than its curli-positive isogenic parent. These findings definitively demonstrate that a single base pair stably confers biofilm formation, epithelial cell invasion, and persistence in cattle.
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页数:17
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