OBJECTIVE To investigate whether the HlyA-induced vacuolating effect is produced by V. cholerae O1 ElTor strains isolated from different geographic origins, including Mexico. MATERIAL AND METHODS Supernatant-induced haemolysis, vacuolating activity and cytotoxicity in Vero cells were recorded. PCR, RFLP analysis and molecular cloning were performed. RESULTS All ElTor strains analyzed induce...

Urban lakes and fountains provide recreational activities that could facilitate the contact between humans, animals and biological agents. The objective of this work was to assess the water quality and safety of 17 lakes and 13 fountains in the city of Porto (Portugal), by detecting the presence of Escherichia coli, enterococci and Salmonella spp., and analyzing their antimicrobial resistance. ...

Commensal, intestinal E. coli microflora plays a role in maintenance of intestinal balance of the host, is responsible for defending against pathogenic E. coli. This study encompasses the analysis of BOX-PCR fingerprinting patterns, phylogenetic grouping and virulence genes prevalence among commensal E. coli isolates derived from healthy pigs. Altogether, 274 unique E. coli isolates were identi...

Alpha-hemolysin (HlyA) is an extracellular toxin secreted by Escherichia coli, targeting to plasma membranes of eukaryotic cells. Recently it was found that this toxin is released to external media associated to bacterial outer membrane vesicles (OMVs), but the hemolytic mechanism in this way has not been studied yet. Our results report that HlyA is the only protein present in OMVs that is resp...

Type-1 fimbriae are important virulence factors for the establishment of Escherichia coli urinary tract infections. Bacterial adhesion to the high-mannosylated uroplakin Ia glycoprotein receptors of bladder epithelium is mediated by the FimH adhesin. Previous studies have attributed differences in mannose-sensitive adhesion phenotypes between faecal and uropathogenic E. coli to sequence variati...

  Introduction : The innate immune system as the first line of defense against the pathogens recognizes pathogen-associated molecular patterns (PAMPs) by Toll-Like Receptors (TLRs). Interaction of bacterial PAMPs by TLRs results in activation of innate and acquired immunity. FimH adhesin, a minor component of type 1 fimbriae encoded by Uropathogenic Escherichia coli (UPEC) is a PAMP of TLR4 tha...

PURPOSE We investigated the molecular types of uropathogenic Escherichia coli (UPEC) by using conventional phylogrouping, multilocus sequence typing (MLST), and fimH genotyping. METHODS Samples of patients younger than 18 years of age were collected from the Chung-Ang University Hospital over 2 years. Conventional phylogenetic grouping for UPEC strains was performed by polymerase chain reacti...

Lipopolysaccharides (LPS) of gram-negative bacteria prime rabbit lungs for enhanced thromboxane-mediated vasoconstriction upon subsequent challenge with the exotoxin Escherichia coli hemolysin (HlyA) (Walmrath et al. J. Exp. Med. 1994;180:1437-1443). We investigated the impact of endotoxin priming and subsequent HlyA challenge on lung vascular permeability while maintaining constancy of capilla...

Production of a single cysteine substitution mutant, S177C, allowed Escherichia coli hemolysin (HlyA) to be radioactively labeled with tritiated N-ethylmaleimide without affecting biological activity. It thus became possible to study the binding characteristics of HlyA as well as of toxin mutants in which one or both acylation sites were deleted. All toxins bound to erythrocytes and granulocyte...

Hemolysin (HlyA) produced by some stains of Escherichia coli is considered to be an important virulence factor of those bacteria. On the other hand, reactive oxygen species (ROS) have been reported to be involved in the pathogenesis of different diseases via oxidative stress generation. The purpose of this study was to analyze the capacity of HlyA to induce oxidative stress in whole blood cultu...