Authors:Abimbola Olumide Adekanmbi, Sandra Usidamen, and Anthony Abiodun Onilude
intestine can acquire specific virulence attributes which confer on them the ability to adapt to new location and then cause a wide range of infections of which UTI is one [ 6 ]. Studies have shown that uropathogenic E. coli (UPEC) group has the ability to
Horizontal gene transfer (HGT) plays a key role in the evolution of bacterial pathogens. The exchange of genetic material supplies prokaryotes with several fitness traits enhancing their adaptive response to environmental changes. Pathogenicity islands (PAIs) represent an important and in most cases already immobilized subset of the different vehicles for HGT. Encoding several virulence factors PAIs represent a major contribution to bacterial pathogenicity. Nonetheless, the transfer mechanisms of PAIs still remain elusive. We summarise the currently available data regarding the major ways of genetic mobilisation with a focus on the transfer of the
High-Pathogenicity Island (HPI).
Authors:Sana Al-Shaikh, Abiola Senok, Abdulrahman Ismaeel, and G. Botta
The association between putative virulence genes in
invasive capability and severity of infection is yet to be clearly described. We have characterized three virulence genes and correlated their presence with the severity of infection and
invasiveness. We studied eight
strains isolated from patients whose clinical data were scored to determine severity of infection. Cytolethal distending toxin
, invasion associated marker
and Campylobacter invasion antigen
genes were detected by PCR and INT407 cells used for invasion assays. Two strains positive for all three genes were the most invasive and isolated from patients with the most severe infection. Four strains positive for two genes and two strains negative for all the three genes were identified. The two
strains were more invasive than the
strains. One of the
strains showed invasion levels similar to
strains, but the second strain had a non-invasive phenotype. The findings indicate a correlation between
invasive capability, and the presence of all three genes. The pattern of association between invasiveness and molecular characterization suggests that the ciaB gene confers a more invasive capability.
Authors:Angela Lacombe-Antoneli, S. Píriz, and S. Vadillo
The present study reports on the location of major foci of footrot in goats in the Extremadura region of Spain by the determination of locally occurring strictly anaerobic microorganisms involved in the pathogenesis and development of this disease. The most commonly isolated microorganisms belonged to the genera Dichelobacter, Fusobacterium, Porphyromonas and Prevotella; these were found in conjunction with other species of minor importance. The species most frequently isolated were Fusobacterium necrophorum (40%), Dichelobacter nodosus (31.7%), Porphyromonas asaccharolytica (21.1%) and Prevotella melaninogenica (12.9%). Virulence factors identified in the isolated microorganisms included haemolysins, elastases and lecithinases, which enabled the organisms involved to initiate and/or aggravate the disease. Serotyping was performed for Dichelobacter nodosus isolates, since this species is responsible for triggering the process of infection. A and C were the most frequently isolated serovarieties (representing 40.7% and 25.9% of the cases, respectively).
Authors:Ágnes Szabó, Zoltán Sipák, András Miczák, and Ildikó Faludi
Better vaccines and new therapeutic drugs could be a successful breakthrough against intracellular bacteria. M. tuberculosis ABC transporter ATPase (Rv0986) plays a role in mycobacterial virulence by inhibiting phagosome-lysosome fusion. Thus, it could be a potential vaccine candidate. C. pneumoniae another important intracellular bacterium possesses a protein named CpB0255, which is homologous with the mycobacterial Rv0986. The aim of this study was the cloning, over-expression and purification of CpB0255 ABC transporter ATPase protein to study its biological properties. The immunogenicity and protective effect of recombinant chlamydial ATPase protein combined with Alum adjuvant were investigated in mice. The immunization resulted in the reduction of the number of viable C. pneumoniae in the lungs after challenge. Our results confirm that chlamydial ATPase induces protective immunity in mice.
Authors:L. Makrai, K. Kira, A. Kono, Y. Sasaki, T. Kakuda, S. Tsubaki, L. Fodor, J. Varga, and S. Takai
virulence plasmids in the isolates from infected foals, dog and monkey. Onderstepoort J. Vet. Res. 68 ,105-110.
Prevalence of virulent Rhodococcus equi in isolates from soil collected from 2 horse farms in South Africa and
Authors:Veronika Müller, Zsuzsanna Kováts, and Gábor Horváth
A létfontosságú szervek elégtelenségének kezelésében a szervtranszplantáció a napi gyakorlat része. A recipiensek közös jellemzője, hogy immunszuppresszív kezelést igényelnek a szervkilökődés megakadályozása érdekében. Az immunszuppresszió növeli az infekcióhajlamot, különösen az egyébként alacsony virulenciájú opportunista kórokozókkal szemben. A szervtranszplantáltak fertőzéseinek jelentős része a tüdőt és a légutakat érinti. Az infekciós komplikációk felismerésében a pulmonológiai diagnosztika, magas szintű mikrobiológiai eljárások és a különböző képalkotó technikák alkalmazhatók. A terápia fejlődése és elérhetősége elengedhetetlen az infekciók eredményes kezeléséhez. Tekintve, hogy a szervtranszplantáltak száma folyamatosan nő, az orvos mind nagyobb számban találkozhat vese-, máj-, szív- vagy tüdőtranszplantált betegek pulmonalis komplikációival. Orv. Hetil., 2012, 153, 899–903.
Authors:L. Kredics, Zsuzsanna Antal, A. Szekeres, L. Hatvani, L. Manczinger, Cs. Vágvölgyi, and Erzsébet Nagy
Cellulolytic, xylanolytic, chitinolytic and b-1,3-glucanolytic enzyme systems of species belonging to the filamentous fungal genus Trichoderma have been investigated in details and are well characterised. The ability of Trichoderma strains to produce extracellular proteases has also been known for a long time, however, the proteolytic enzyme system is relatively unknown in this genus. Fortunately, in the recent years more and more attention is focused on the research in this field. The role of Trichoderma proteases in the biological control of plant pathogenic fungi and nematodes has been demonstrated, and it is also suspected that they may be important for the competitive saprophytic ability of green mould isolates and may represent potential virulence factors of Trichoderma strains as emerging fungal pathogens of clinical importance. The aim of this review is to summarize the information available about the extracellular proteases of Trichoderma. Numerous studies are available about the extracellular proteolytic enzyme profiles of Trichoderma strains and about the effect of abiotic environmental factors on protease activities. A number of protease enzymes have been purified to homogeneity and some protease encoding genes have been cloned and characterized. These results will be reviewed and the role of Trichoderma proteases in biological control as well as their advantages and disadvantages in biotechnology will be discussed.
Authors:Ildikó Nyilasi, T. Papp, M. Takó, Erzsébet Nagy, and Cs. Vágvölgyi
Iron is an essential nutrient for most organisms because it serves as a catalytic cofactor in oxidation-reduction reactions. Iron is rather unavailable because it occurs in its insoluble ferric form in oxides and hydroxides, while in serum of mammalian hosts is highly bound to carrier proteins such as transferrin, so the free iron concentration is extremely low insufficient for microbial growth. Therefore, many organisms have developed different iron-scavenging systems for solubilizing ferric iron and transporting it into cells across the fungal membrane. There are three major mechanisms by which fungi can obtain iron from the host: (a) utilization of a high affinity iron permease to transport iron intracellularly, (b) production and secretion of low molecular weight iron-specific chelators (siderophores), (c) utilization of a hem oxygenase to acquire iron from hemin. Patients with elevated levels of available serum iron treated with iron chelator, deferoxamine to remedy iron overload conditions have an increased susceptibility of invasive zygomycosis. Presumably deferoxamine predisposes patients to Zygomycetes infections by acting as a siderophore. The frequency of zygomycosis is increasing in recent years and these infections respond very poorly to currently available antifungal agents, so new approaches to develop strategies to prevent and treat zygomycosis are urgently needed. Siderophores and iron-transport proteins have been suggested to function as virulence factors because the acquisition of iron is a crucial pathogenetic event. Biosynthesis and uptake of siderophores represent possible targets for antifungal therapy.
Pathogenicity and virulence are multifactorial traits, depending on interaction of viruses with susceptible cells and organisms. The ion channels coded by viruses, viroporins, represent only one factor taking part in the cascade of interactions between virus and cell, leading to the entry of virus, replication and to profound changes in membrane permeability. The M2 protein from influenza A virus forms proton-selective, pH-regulated channel involved in regulating vesicular pH, a function important for the correct maturation of HA glycoprotein. The NB glycoprotein of influenza B viruses is an integral membrane protein with an ion channel activity. The CM2 protein of influenza C virus is an integral membrane glycoprotein structurally analogous to influenza A virus M2 and influenza B virus NB proteins. The picornavirus 3A protein is involved in cell lysis and shows homology with other lytic proteins. Vpu is an oligomeric integral membrane protein encoded by HIV-1, which forms ion channels. The togavirus 6K protein shows structural similarities with other viroporins.