MPL36, a major plasminogen (PLG) receptor in pathogenic Leptospira, has an essential role during infection.

Leptospirosis, a zoonosis with worldwide distribution, is caused by pathogenic spirochetes belonging to the genus Leptospira. Bacterial outer membrane proteins (OMPs), particularly those with surface-exposed regions, play crucial roles in pathogen dissemination and virulence mechanisms. Here we characterized the leptospiral Membrane Protein L36 (MPL36), a rare lipoprotein A (RlpA) homolog with a C-terminal Sporulation related (SPOR) domain, as an important virulence factor in pathogenic Leptospira.

Adhesin related genes as potential markers for the enteroaggregative category.

Enteroaggregative (EAEC) is an important cause of diarrhea in children and adults worldwide. This pathotype is phenotypically characterized by the aggregative-adherence (AA) pattern in HEp-2 cells and genetically associated to the presence of the gene. EAEC pathogenesis relies in different virulence factors.

Role of aggregate-forming pilus (AFP) in adherence and colonization of both intestinal and urinary tracts.

Hybrid-pathogenic represent an important group of strains associated with intestinal and extraintestinal infections. Recently, we described strain UPEC-46, a uropathogenic/enteroaggregative (UPEC/EAEC) strain presenting the aggregative adherence (AA) pattern on bladder and colorectal epithelial cells mediated by aggregate-forming pili (AFP). However, the role of AFP and other uninvestigated putative fimbriae operons in UPEC-46 pathogenesis remains unclear.

The aggregate-forming pili (AFP) mediates the aggregative adherence of a hybrid-pathogenic (UPEC/EAEC) isolated from a urinary tract infection.

Enteroaggregative (EAEC) comprises an important diarrheagenic pathotype, while uropathogenic (UPEC) is the most important agent of urinary tract infection (UTI). Recently, EAEC virulence factors have been detected in strains causing UTI, showing the importance of these hybrid-pathogenic strains. Previously, we detected an strain isolated from UTI (UPEC-46) presenting characteristics of EAEC, .

EspFu-Mediated Actin Assembly Enhances Enteropathogenic Adherence and Activates Host Cell Inflammatory Signaling Pathways.

The translocation of effectors into the host cell through type 3 secretion systems (T3SS) is a sophisticated strategy employed by pathogenic bacteria to subvert host responses and facilitate colonization. Enteropathogenic (EPEC) and enterohemorrhagic (EHEC) utilize the Tir and EspFu (also known as TccP) effectors to remodel the host cytoskeleton, culminating in the formation of attaching and effacing (AE) lesions on enterocytes. While some EPEC strains require tyrosine phosphorylation of Tir and recruitment of the host Nck to trigger actin polymerization, EHEC and certain EPEC strains, whose Tir is not phosphorylated, rely on the effector EspFu for efficient actin remodeling.

Interactions of Shiga toxin-producing Escherichia coli with leafy green vegetables.

Shiga toxin-producing Escherichia coli (STEC) are important foodborne pathogens responsible for a wide spectrum of diseases including diarrhea, bloody diarrhea, and hemolytic uremic syndrome (HUS). A considerable number of outbreaks and sporadic cases of HUS have been associated with ingestion of fresh ready-to-eat products. Maintenance and persistence of STEC in the environment and foods can be related to its ability to form biofilm.

The Type III Secretion System (T3SS)-Translocon of Atypical Enteropathogenic (aEPEC) Can Mediate Adherence.

The intimin protein is the major adhesin involved in the intimate adherence of atypical enteropathogenic (aEPEC) strains to epithelial cells, but little is known about the structures involved in their early colonization process. A previous study demonstrated that the type III secretion system (T3SS) plays an additional role in the adherence of an strain. Therefore, we assumed that the T3SS could be related to the adherence efficiency of aEPEC during the first stages of contact with epithelial cells.

Dynamic Gene Network Analysis of Caco-2 Cell Response to Shiga Toxin-Producing -Associated Hemolytic-Uremic Syndrome.

Shiga toxin-producing (STEC) O113:H21 strains are associated with human diarrhea and some strains may cause hemolytic-uremic syndrome (HUS). In Brazil, these strains are commonly found in cattle but, so far, were not isolated from HUS patients. Here, a system biology approach was used to investigate the differential transcriptomic and phenotypic responses of enterocyte-like Caco-2 cells to two STEC O113:H21 strains with similar virulence factor profiles (i.

Novel Hybrid of Typical Enteropathogenic and Shiga-Toxin-Producing (tEPEC/STEC) Emerging From Pet Birds.

Exotic psittacine birds have been implicated as reservoir of diarrheagenic (), including enteropathogenic (EPEC) and Shiga-toxin producing (STEC). Here, we present a genotypic and phenotypic characterization of typical EPEC/STEC hybrid strains isolated from exotic psittacine birds. The strains were positive for , A, and s2f genes, belong to serotype O137:H6 and ST2678.

Distribution of Major Pilin Subunit Genes Among Atypical Enteropathogenic and Influence of Growth Media on Expression of the Operon.

Atypical enteropathogenic (aEPEC) strains are unable to produce the bundle-forming pilus (BFP), which is responsible for the localized adherence pattern, a characteristic of the pathogenicity of typical EPEC strains. The lack of BFP in aEPEC strains suggests that other fimbrial or non-fimbrial adhesins are involved in their adhesion to the host cells. The aim of this study was to investigate the distribution of major subunit fimbrial genes known to be important adherence factors produced by several pathotypes in a collection of 72 aEPEC strains.

A hemolytic-uremic syndrome-associated strain O113:H21 Shiga toxin-producing Escherichia coli specifically expresses a transcriptional module containing dicA and is related to gene network dysregulation in Caco-2 cells.

Shiga toxin-producing (Stx) Escherichia coli (STEC) O113:H21 strains are associated with human diarrhea and some of these strains may cause hemolytic uremic syndrome (HUS). The molecular mechanism underlying this capacity and the differential host cell response to HUS-causing strains are not yet completely understood. In Brazil O113:H21 strains are commonly found in cattle but, so far, were not isolated from HUS patients.

Escherichia albertii, a novel human enteropathogen, colonizes rat enterocytes and translocates to extra-intestinal sites.

Diarrhea is the second leading cause of death of children up to five years old in the developing countries. Among the etiological diarrheal agents are atypical enteropathogenic Escherichia coli (aEPEC), one of the diarrheagenic E. coli pathotypes that affects children and adults, even in developed countries.

The serine protease Pic as a virulence factor of atypical enteropathogenic Escherichia coli.

Autotransporter proteins (AT) are associated with bacterial virulence attributes. Originally identified in enteroaggregative Escherichia coli (EAEC), Shigella flexneri 2a and uropathogenic E. coli, the serine protease Pic is one of these AT.

Pathogenic Leptospira species acquire factor H and vitronectin via the surface protein LcpA.

Upon infection, pathogenic Leptospira species bind several complement regulators in order to overcome host innate immunity. We previously characterized a 20-kDa leptospiral surface protein which interacts with C4b binding protein (C4BP): leptospiral complement regulator-acquiring protein A (LcpA). Here we show that LcpA also interacts with human factor H (FH), which remains functionally active once bound to the protein.

Atypical enteropathogenic Escherichia coli strains form biofilm on abiotic surfaces regardless of their adherence pattern on cultured epithelial cells.

The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC) strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV) assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm(2) counting and confocal laser scanning microscopy (CLSM).

Invasion of differentiated intestinal Caco-2 cells is a sporadic property among atypical enteropathogenic Escherichia coli strains carrying common intimin subtypes.

Atypical enteropathogenic Escherichia coli (aEPEC) strains produce attaching-effacing (AE) lesions on enterocytes due to the interaction of the adhesin intimin with its translocated receptor. aEPEC strain 1551-2 was previously shown to invade HeLa and T84 cells by means of the uncommon intimin subtype omicron. Other aEPEC strains carrying uncommon intimin subtypes have also been shown to invade differentiated T84 intestinal cells.

Interaction of Leptospira elongation factor Tu with plasminogen and complement factor H: a metabolic leptospiral protein with moonlighting activities.

The elongation factor Tu (EF-Tu), an abundant bacterial protein involved in protein synthesis, has been shown to display moonlighting activities. Known to perform more than one function at different times or in different places, it is found in several subcellular locations in a single organism, and may serve as a virulence factor in a range of important human pathogens. Here we demonstrate that Leptospira EF-Tu is surface-exposed and performs additional roles as a cell-surface receptor for host plasma proteins.

Generation of recombinant bacillus Calmette-Guérin and Mycobacterium smegmatis expressing BfpA and intimin as vaccine vectors against enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) is an important cause of diarrhea in children. EPEC adheres to the intestinal epithelium and causes attaching and effacing (A/E) lesions. Recombinant Mycobacterium smegmatis (Smeg) and Mycobacterium bovis BCG strains were constructed to express either BfpA or intimin.

Low-molecular mass comparative proteome of four atypical enteropathogenic Escherichia coli isolates showing different adherence patterns.

Atypical enteropathogenic Escherichia coli (aEPEC) are heterogeneous in terms of serotypes, adherence patterns and the presence of non-locus of enterocyte effacement virulence factors. In this study, the low-molecular mass proteomes of four representative aEPEC, comprising three different adhesion phenotypes (localized-like, aggregative and diffuse) and one non-adherent isolate, were analyzed and compared by 2D gel electrophoresis and LC-MS/MS. By mass spectrometry, a total of 59 proteins were identified according to their annotated function, with most of them being involved in metabolism, protection, and transport; some of them still classified as hypothetical proteins.

Atypical enteropathogenic Escherichia coli that contains functional locus of enterocyte effacement genes can be attaching-and-effacing negative in cultured epithelial cells.

Enteropathogenic Escherichia coli (EPEC) induces a characteristic histopathology on enterocytes known as the attaching-and-effacing (A/E) lesion, which is triggered by proteins encoded by the locus of enterocyte effacement (LEE). EPEC is currently classified as typical EPEC (tEPEC) and atypical EPEC (aEPEC), based on the presence or absence of the EPEC adherence factor plasmid, respectively. Here we analyzed the LEE regions of three aEPEC strains displaying the localized adherence-like (LAL), aggregative adherence (AA), and diffuse adherence (DA) patterns on HEp-2 cells as well as one nonadherent (NA) strain.

Determination of adhesin gene sequences in, and biofilm formation by, O157 and non-O157 Shiga toxin-producing Escherichia coli strains isolated from different sources.

Biofilm formation by Shiga toxin-producing Escherichia coli (STEC) has been associated with the expression of different adhesins (type 1 fimbria, curli, Ag43, Cah, and EhaA). In this study, biofilm formation and the presence of adhesin-related gene sequences were determined by PCR in 18 O157 strains and 33 non-O157 strains isolated from different sources (human, animal, food, and water). The expression of different adhesins was also assessed by reverse transcription-PCR (RT-PCR), Congo red agar plates, and mannose-sensitive hemagglutination (MSHA) assay.

HeLa-cell adherence patterns and actin aggregation of enteropathogenic Escherichia coli (EPEC) and Shiga-toxin-producing E. coli (STEC) strains carrying different eae and tir alleles.

A collection of 69 eae-positive strains expressing 29 different intimin types and eight tir alleles was characterized with respect to their adherence patterns to HeLa cells, ability to promote actin accumulation in vitro, the presence of bfpA alleles in positive strains, and bundle-forming pilus (BFP) expression. All of the nine typical enteropathogenic Escherichia coli (tEPEC) studied harbored the enteropathogenic E. coli adherence factor (EAF) plasmid, as shown by PCR and/or EAF probe results.

Pseudomonas aeruginosa PA14 cupD transcription is activated by the RcsB response regulator, but repressed by its putative cognate sensor RcsC.

The opportunistic pathogen Pseudomonas aeruginosa PA14 possesses four fimbrial cup clusters, which may confer the ability to adapt to different environments. cupD lies in the pathogenicity island PAPI-1 next to genes coding for a putative phosphorelay system composed of the hybrid histidine kinase RcsC and the response regulator RcsB. The main focus of this work was the regulation of cupD at the mRNA level.

The flagella of an atypical enteropathogenic Escherichia coli strain are required for efficient interaction with and stimulation of interleukin-8 production by enterocytes in vitro.

The ability of some typical enteropathogenic Escherichia coli (EPEC) strains to adhere to, invade, and increase interleukin-8 (IL-8) production in intestinal epithelial cells in vitro has been demonstrated. However, few studies regarding these aspects have been performed with atypical EPEC (aEPEC) strains, which are emerging enteropathogens in Brazil. In this study, we evaluated a selected aEPEC strain (1711-4) of serotype O51:H40, the most prevalent aEPEC serotype in Brazil, in regard to its ability to adhere to and invade Caco-2 and T84 cells and to elicit IL-8 production in Caco-2 cells.

Virulence features of atypical enteropathogenic Escherichia coli identified by the eae(+) EAF-negative stx(-) genetic profile.

This study characterized 76 atypical enteropathogenic Escherichia coli (aEPEC) strains, previously classified by the eae(+) EAF-negative stx(-) genotype, isolated from children with diarrhea in Brazil. Presence of bfpA and bfpA/perA was detected in 2 and 6 strains, respectively. The expression of bundle-forming pilus (BFP), however, was observed by immunofluorescence in 1 bfpA and 3 bfpA/perA strains, classifying them as typical EPEC (tEPEC).