Genotypic and phenotypic variation among Staphylococcus saprophyticus from human and animal isolates

<p>Abstract</p> <p>Background</p> <p>The main aim of this study was to examine the genotypic and phenotypic diversity of <it>Staphylococcus saprophyticus </it>isolates from human and animal origin.</p> <p>Findings</p> <p>In total, 236 clinical isolates and 15 animal isolates of <it>S. saprophyticus </it>were characterized in respect of the occurrence of 9 potential virulence genes and four surface properties. All strains were PCR positive for the regulatory genes <it>agr</it>, <it>sar</it>>it>A and <it>rot </it>as well as for the surface proteins UafA and Aas. Nearly 90% of the clinical isolates were found to possess the gene for the surface-associated lipase Ssp and 10% for the collagen binding MSCRAMM SdrI. All animal isolates were negative for<it>sdrI</it>. Lipolytic activity could be detected in 66% of the clinical and 46% of the animal isolates. Adherence to collagen type I was shown of 20% of the clinical strains and 6% of the strains of animal origin. Most <it>S. saprophyticus </it>strains showed hydrophobic properties and only few could agglutinate sheep erythrocytes.</p> <p>Conclusions</p> <p>We described a broad analysis of animal and human <it>S. saprophyticus </it>isolates regarding virulence genes and phenotypic properties such as lipase activity, hydrophobicity, and adherence. While <it>S. saprophyticus </it>strains from animal sources have prerequisites for colonization of the urinary tract like the D-serine-deaminase, out findings suggested that they need to acquire new genes e.g. MSCRAMMS for adherence like sdrI and to modulate their existing properties e.g. increasing the lipase activity or reducing hydrophobicity. These apparently important new genes or properties for virulence have to be further analyzed.</p

The effect of octopaminergic compounds on the behaviour and transmission of Gyrodactylus

Background: The high transmission potential of species belonging to the monogenean parasite genus Gyrodactylus, coupled with their high fecundity, allows them to rapidly colonise new hosts and to increase in number. One gyrodactylid, Gyrodactylus salaris Malmberg, 1957, has been responsible for devastation of Altantic salmon (Salmo salar L.) populations in a number of Norwegian rivers. Current methods of eradicating G. salaris from river systems centre around the use of non-specific biocides, such as rotenone and aluminium sulphate. Although transmission routes in gyrodactylids have been studied extensively, the behaviour of individual parasites has received little attention. Specimens of Gyrodactylus gasterostei Gl&auml;ser, 1974 and G. arcuatus Bychowsky, 1933, were collected from the skin of their host, the three-spined stickleback (Gasterosteus aculeatus L.), and permitted to attach to the substrate. The movements of individual parasites were recorded and analysed. Results: The behaviour patterns of the two species were similar and parasites were more active in red light and darkness than in white light. Four octopaminergic compounds were tested and all four inhibited the movements of parasites. Treatment ultimately led to death at low concentrations (0.2 &mu;M), although prolonged exposure was necessary in some instances. Conclusions: Octopaminergic compounds may affect the parasite's ability to locate and remain on its host and these or related compounds might provide alternative or supplementary treatments for the control of G. salaris infections. With more research there is potential for use of octopaminergic compounds, which have minimal effects on the host or its environment, as parasite-specific treatments against G. salaris infections

The disruption of proteostasis in neurodegenerative diseases

Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Characterisation of the Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop)

Malaria is caused by Plasmodium species, whose transmission to vertebrate hosts is facilitated by mosquito vectors. The transition from the cold blooded mosquito vector to the host represents physiological stress to the parasite, and additionally malaria blood stage infection is characterised by intense fever periods. In recent years, it has become clear that heat shock proteins play an essential role during the parasite's life cycle. Plasmodium falciparum expresses two prominent heat shock proteins: heat shock protein 70 (PfHsp70) and heat shock protein 90 (PfHsp90). Both of these proteins have been implicated in the development and pathogenesis of malaria. In eukaryotes, Hsp70 and Hsp90 proteins are functionally linked by an essential adaptor protein known as the Hsp70–Hsp90 organising protein (Hop). In this study, recombinant P. falciparum Hop (PfHop) was heterologously produced in E. coli and purified by nickel affinity chromatography. Using specific anti-PfHop antisera, the expression and localisation of PfHop in P. falciparum was investigated. PfHop was shown to co-localise with PfHsp70 and PfHsp90 in parasites at the trophozoite stage. Gel filtration and coimmunoprecipitation experiments suggested that PfHop was present in a complex together with PfHsp70 and PfHsp90. The association of PfHop with both PfHsp70 and PfHsp90 suggests that this protein may mediate the functional interaction between the two chaperones

Alternate spore stages of Myxobilatus gasterostei, a myxosporean parasite of three-spined sticklebacks (Gasterosteus aculeatus) and oligochaetes (Nais communis)

Two spore stages in the life cycle of Myxobilatus gasterostei, a ubiquitous myxosporean parasite of three-spined sticklebacks, were identified by matching small subunit ribosomal RNA gene sequences of actinospores from a worm with myxospores from fish. A Nais communis oligochaete collected in the Willamette River, Oregon, USA was found to produce a triactinomyxon-type actinospore which was distinguishable from previous records by its large size (approximately 500 microm across) and number of germ cells (approximately 500). Its small subunit ribosomal RNA gene sequence was >99% similar to M. gasterostei from Europe. Two of ten sticklebacks from the Willamette had renal infections with Myxobilatus myxospores which were smaller than the type description of M. gasterostei Parisi (1912) but were consistent with subsequent records. Primer Mg1097r was designed to selectively amplify M. gasterostei in the presence of another common kidney myxosporean, Sphaerospora elegans. DNA sequences of spores from the fish were identical to each other and were 99.8% similar over 2,112 nt to the spores from the oligochaete. The 0.2% sequence divergence comprised polymorphisms at five loci, which suggested that multiple alleles were present in the parasite population. This is the first Myxobilatus species shown to have two spore stages in its life cycle and to infect an invertebrate. The infected oligochaete underwent paratomic fission to produce two daughter worms with parasite stages in their intestinal epithelia, which suggested that M. gasterostei may be sustained and dispersed within the invertebrate host population