Search results for "VIRULENCE FACTORS"
showing 10 items of 67 documents
The Fish Pathogen Vibrio vulnificus Biotype 2: Epidemiology, Phylogeny, and Virulence Factors Involved in Warm-Water Vibriosis
2015
ABSTRACT Vibrio vulnificus biotype 2 is the etiological agent of warm-water vibriosis, a disease that affects eels and other teleosts, especially in fish farms. Biotype 2 is polyphyletic and probably emerged from aquatic bacteria by acquisition of a transferable virulence plasmid that encodes resistance to innate immunity of eels and other teleosts. Interestingly, biotype 2 comprises a zoonotic clonal complex designated as serovar E that has extended worldwide. One of the most interesting virulence factors produced by serovar E is RtxA1 3 , a multifunctional protein that acts as a lethal factor for fish, an invasion factor for mice, and a survival factor outside the host. Two practically id…
Characterization of Listeria monocytogenes isolates from human listeriosis cases in Italy.
2009
ABSTRACT The objective of this study was to characterize by serotyping, pulsed-field gel electrophoresis (PFGE), and PCR amplification of virulence genes and markers of epidemic clones I, II, and III (ECI, ECII, and ECIII) 54 human isolates from apparently sporadic cases of infection occurring in the Lombardy region and in the province of Florence, Tuscany, Italy, in the years 1996 to 2007. Listeria monocytogenes isolates were provided by the clinical microbiology laboratories of the Lombardy region and the “Careggi” Hospital of Florence, Tuscany, Italy. Serotyping, PFGE after digestion with the AscI and ApaI enzymes, and PCR amplification for the inlA , inlC , and inlJ genes and ECI, ECII,…
Resistance to clarithromycin and genotypes in Helicobacter pylori strains isolated in Sicily
2015
The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25 % of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48 % of case…
Staphylococcus aureus α-Toxin’s Close Contacts Ensure the Kill
2018
The membrane pore-forming α-toxin is an important virulence factor of Staphylococcus aureus. Target cells can remove pores from their surface, but recent work shows that α-toxin may undermine this self-defense by clinging to epithelial cell junctions. The findings could lead to the development of novel remedies against S. aureus infections.
Comparing the different morphotypes of a fish pathogen - implications for key virulence factors in Flavobacterium columnare
2014
Background: Flavobacterium columnare (Bacteroidetes) is the causative agent of columnaris disease in farmed freshwater fish around the world. The bacterium forms three colony morphotypes (Rhizoid, Rough and Soft), but the differences of the morphotypes are poorly known. We studied the virulence of the morphotypes produced by F. columnare strain B067 in rainbow trout ( Onconrhynchus mykiss ) and used high-resolution scanning electron microscopy to identify the fine structures of the cells grown in liquid and on agar. We also analysed the proteins secreted extracellularly and in membrane vesicles to identify possible virulence factors. Results: Only the Rhizoid morphotype was virulent in rain…
Crystal structure of the N-terminal domain of the major virulence factor BB0323 from the Lyme disease agent Borrelia burgdorferi.
2019
Lyme disease is an infection caused by the spirochete Borrelia burgdorferi after it is transmitted to a mammalian organism during a tick blood meal. B. burgdorferi encodes at least 140 lipoproteins located on the outer or inner membrane, thus facing the surroundings or the periplasmic space, respectively. However, most of the predicted lipoproteins are of unknown function, and only a few proteins are known to be essential for the persistence and virulence of the pathogen. One such protein is the periplasmic BB0323, which is indispensable for B. burgdorferi to cause Lyme disease and the function of which is associated with cell fission and outer membrane integrity. After expression and trans…
The structure of Yersinia pestis Caf1 polymer in free and adjuvant bound states
2010
Caf1 of the plague bacterium, Yersinia pestis is a polymeric virulence factor and vaccine component, formed from monomers by a donor strand exchange (DSE) mechanism. Here, EM images of Caf1 reveal flexible polymers up to 1.5 microm long (4MDa). The bead-like structures along the polymer are 5.8 + or - 1 nm long and correspond to single Caf1 proteins. Short polymers often form circles, presumably by DSE. We also provide the first images of proteins bound to alhydrogel adjuvant. Caf1, hemocyanin and anthrax PA are all resolved clearly and Caf1 exhibits adjuvant bound stretches with long intervening loops draped from the edges.
Tools for Pathogen Proteomics: Fishing with Biomimetic Nanosponges
2017
The identification of the major virulence factors that drive pathogenicity is critical for gaining insight into the underlying molecular mechanisms of diseases. Although genetic approaches combined with functional analyses have markedly increased the rate of virulence factor discovery, the divergence between genome and proteome can impair the identification of important markers, in particular, of those that act in concert or depend on specific environmental factors. Recently, membrane-coated nanomaterials mimicking source cells of interest have emerged as powerful tools that can be used for improved tumor targeting and as "nanotraps" to capture chemokines and bacterial toxins. In this issue…
N-acyl-homoserine-lactone quorum sensing in tomato phytopathogenic Pseudomonas spp. is involved in the regulation of lipodepsipeptide production
2012
Pseudomonas corrugata and Pseudomonas mediterranea are two closely related phytopathogenic bacteria both causal agents of tomato pith necrosis. P. corrugata produces phytotoxic and antimicrobial cationic lipodepsipeptides (LDPs) which are thought to act as major virulence factors. Previous studies have demonstrated that P. corrugata CFBP 5454 has an N-acyl homoserine lactone (AHL) quorum sensing (QS) system PcoI/PcoR and that LDP production occurs at high population densities. No molecular studies on virulence have thus far been reported for P. mediterranea. In this study, we show that P. mediterranea also produces LDPs as well as possessing an AHL-dependent QS system, designated PmeI/PmeR,…
Salmonella bongori Provides Insights into the Evolution of the Salmonellae
2011
The genus Salmonella contains two species, S. bongori and S. enterica. Compared to the well-studied S. enterica there is a marked lack of information regarding the genetic makeup and diversity of S. bongori. S. bongori has been found predominantly associated with cold-blooded animals, but it can infect humans. To define the phylogeny of this species, and compare it to S. enterica, we have sequenced 28 isolates representing most of the known diversity of S. bongori. This cross-species analysis allowed us to confidently differentiate ancestral functions from those acquired following speciation, which include both metabolic and virulence-associated capacities. We show that, although S. bongori…