Role of the hipBA Locus in antibiotic tolerance of uropathogenic Escherichia coli

ABSTRACT Uropathogenic Escherichia coli (UPEC) causes most uncomplicated urinary tract infections (UTIs) in humans. Flagellum-mediated motility and chemotaxis have been suggested to contribute to virulence by enabling UPEC to escape host immune responses and disperse to new sites within the urinary tract. To evaluate their contribution to virulence, six separate flagellar mutations were constructed in UPEC strain CFT073. The mutants constructed were shown to have four different flagellar phenotypes: fliA and fliC mutants do not produce flagella; the flgM mutant has similar levels of extracellular flagellin as the wild type but exhibits less motility than the wild type; the motAB mutant is nonmotile; and the cheW and cheY mutants are motile but nonchemotactic. Virulence was assessed by transurethral independent challenges and cochallenges of CBA mice with the wild type and each mutant. CFU/ml of urine or CFU/g bladder or kidney was determined 3 days postinoculation for the independent challenges and at 6, 16, 48, 60, and 72 h postinoculation for the cochallenges. While these mutants colonized the urinary tract during independent challenge, each of the mutants was outcompeted by the wild-type strain to various degrees at specific time points during cochallenge. Altogether, these results suggest that flagella and flagellum-mediated motility/chemotaxis may not be absolutely required for virulence but that these traits contribute to the fitness of UPEC and therefore significantly enhance the pathogenesis of UTIs caused by UPEC.

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FNR Regulates Expression of Important Virulence Factors Contributing to Pathogenicity of Uropathogenic Escherichia coli

Infection and Immunity ◽

10.1128/iai.02315-14 ◽

2014 ◽

Vol 82 (12) ◽

pp. 5086-5098 ◽

Cited By ~ 28

Author(s):

Nicolle L. Barbieri ◽

Bryon Nicholson ◽

Ashraf Hussein ◽

Wentong Cai ◽

Yvonne M. Wannemuehler ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Factors ◽

Bacterial Infections ◽

Uropathogenic Escherichia Coli ◽

Type I ◽

Wild Type ◽

Global Regulator ◽

Content Type ◽

Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) is responsible for the majority of urinary tract infections (UTIs), which are some of the world's most common bacterial infections of humans. Here, we examined the role of FNR (fumarate andnitratereduction), a well-known global regulator, in the pathogenesis of UPEC infections. We constructed anfnrdeletion mutant of UPEC CFT073 and compared it to the wild type for changes in virulence, adherence, invasion, and expression of key virulence factors. Compared to the wild type, thefnrmutant was highly attenuated in the mouse model of human UTI and showed severe defects in adherence to and invasion of bladder and kidney epithelial cells. Our results showed that FNR regulates motility and multiple virulence factors, including expression of type I and P fimbriae, modulation of hemolysin expression, and expression of a novel pathogenicity island involved in α-ketoglutarate metabolism under anaerobic conditions. Our results demonstrate that FNR is a key global regulator of UPEC virulence and controls expression of important virulence factors that contribute to UPEC pathogenicity.

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Involvement of biofilm-like in tracellular bacterial communities of uropathogenic Escherichia coli in pathogenesis of urinary tract infections – a mini review

Current Issues in Pharmacy and Medical Sciences ◽

10.12923/j.2084-980x/26.3/a.18 ◽

2013 ◽

Vol 26 (3) ◽

pp. 321-325

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Urinary Tract Infections ◽

Bacterial Communities ◽

Uropathogenic Escherichia Coli ◽

E Coli ◽

Etiologic Agents ◽

Tract Infections ◽

Intracellular Bacterial Communities

This paper presents a precisely defined question about the role of the biofilm-like intracellular bacterial communities in pathogenesis of the urinary tract infections. According to the recent literature, uropathogenic Escherichia coli is one of the leading etiologic agents of the urinary tract infections. Although E. coli is regarded as an extracellular pathogen, some experiments have revealed a multi-step infection cycle, which involves adhesion, invasion, proliferation within invaded urothelial cell in the form of biofilm-like intracellular bacterial communities and dispersal, leading to infection of next neighbouring cells. Therefore, the prevention and treatment of the urinary tract infections must include intracellular stage of infection.

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