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Outer membrane vesicles (OMVs) carrying virulence factors of enterohemorrhagic Escherichia coli (EHEC) are assumed to play a role in the pathogenesis of life-threatening hemolytic uremic syndrome (HUS). However, it is unknown if and how OMVs, which are produced in the intestinal lumen, cross the intestinal epithelial barrier (IEB) to reach the renal glomerular endothelium, the major target in HUS. We investigated the ability of EHEC O157 OMVs to translocate across the IEB using a model of polarized Caco-2 cells grown on Transwell inserts and characterized important aspects of this process. Using unlabeled or fluorescently labeled OMVs, tests of the intestinal barrier integrity, inhibitors of endocytosis, cell viability assay, and microscopic techniques, we demonstrated that EHEC O157 OMVs translocated across the IEB. OMV translocation involved both paracellular and transcellular pathways and was significantly increased under simulated inflammatory conditions. In addition, translocation was not dependent on OMV-associated virulence factors and did not affect viability of intestinal epithelial cells. Importantly, translocation of EHEC O157 OMVs was confirmed in human colonoids thereby supporting physiological relevance of OMVs in the pathogenesis of HUS. [ABSTRACT FROM AUTHOR]

Despite unfavorable Antarctic conditions, such as cold temperatures, freeze-thaw cycles, high ultraviolet radiation, dryness and lack of nutrients, microorganisms were able to adapt and surprisingly thrive in this environment. In this study, eight cold-adapted Flavobacterium strains isolated from a remote Antarctic island, James Ross Island, were studied using a polyphasic taxonomic approach to determine their taxonomic position. Phylogenetic analyses based on the 16S rRNA gene and 92 core genes clearly showed that these strains formed two distinct phylogenetic clusters comprising three and five strains, with average nucleotide identities significantly below 90% between both proposed species as well as between their closest phylogenetic relatives. Phenotyping revealed a unique pattern of biochemical and physiological characteristics enabling differentiation from the closest phylogenetically related Flavobacterium spp. Chemotaxonomic analyses showed that type strains P4023T and P7388T were characterized by the major polyamine sym- homospermidine and a quinone system containing predominantly menaquinone MK-6. In the polar lipid profile phosphatidylethanolamine, an ornithine lipid and two unidentified lipids lacking a functional group were detected as major lipids. These characteristics along with fatty acid profiles confirmed that these species belong to the genus Flavobacterium. Thorough genomic analysis revealed the presence of numerous cold-inducible or cold-adaptation associated genes, such as cold-shock proteins, proteorhodopsin, carotenoid biosynthetic genes or oxidative-stress response genes. Genomes of type strains surprisingly harbored multiple prophages, with many of them predicted to be active. Genome-mining identified biosynthetic gene clusters in type strain genomes with a majority not matching any known clusters which supports further exploratory research possibilities involving these psychrotrophic bacteria. Antibiotic susceptibility testing revealed a pattern of multidrug-resistant phenotypes that were correlated with in silico antibiotic resistance prediction. Interestingly, while typical resistance finder tools failed to detect genes responsible for antibiotic resistance, genomic prediction confirmed a multidrug-resistant profile and suggested even broader resistance than tested. Results of this study confirmed and thoroughly characterized two novel psychrotrophic Flavobacterium species, for which the names Flavobacterium flabelliforme sp. nov. and Flavobacterium geliluteum sp. nov. are proposed. [ABSTRACT FROM AUTHOR]

Copyright of Hygiena is the property of Statni Zdravotni Ustav and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A wide range of viral agents is associated with the development of acute myocarditis and its possible chronic sequela, dilated cardiomyopathy (DCM). There is also increasing evidence that Borrelia burgdorferi ( Bb) is associated with DCM in endemic regions for Bb infection. This study sought to use electron microscopy to prospectively analyze the presence of viruses and Bb within the myocardium of 40 subjects with preserved left ventricular (LV) ejection fraction and 40 patients with new-onset unexplained DCM during the same time period. Virus particles were found within the myocardium of 23 subjects (58 %) of both cohorts studied, yet there was no statistically significant difference in virus family presence between those with DCM versus those with preserved LV systolic function. In contrast, Bb was detected only in those subjects with DCM (0 versus 5 subjects; p ˂ 0.05). Polymerase chain reaction was performed on samples from patients who were positive for Bb according to electron microscopy, and Bb was confirmed in 4 out of 5 individuals. Our results demonstrate that the prevalence of viral particles does not differ between subjects with preserved LV systolic function versus those with DCM and therefore suggests that the mere presence of a viral agent within the myocardium is not sufficient to establish a clear link with the development of DCM. In contrast, the presence of Bb was found only within myocardial samples of patients with DCM; this finding supports the idea of a causal relationship between Bb infection and DCM development. [ABSTRACT FROM AUTHOR]

The aim of our study was to find out the optimal conditions for short-term storage of cerebrospinal fluid (CSF) samples for direct diagnosis of Lyme disease. A mixture of Borrelia-negative CSFs spiked with a defined amount of cultured Borrelia garinii was used. Borrelia stability was investigated over 7 days at four different temperatures [room temperature (RT), +4, −20 and −70 °C]. Quantitative changes in CSF Borrelia were measured by quantitative PCR (qPCR), and morphological changes in the spirochetes were observed by transmission electron microscopy (TEM). These qPCR results were statistically evaluated. We found +4 °C to be an optimal temperature for short-term storage of CSF samples intended for TEM observation. There was no significant difference between the temperatures tested in the average quantity of Borrelia measured by qPCR. On the contrary, electron optical diagnosis of frozen samples and samples stored at RT showed destructive morphological changes and decreased spirochete counts. Our results show that optimal conditions for the pre-analytical phase of investigation of one type of material can differ depending on the diagnostic method employed. [ABSTRACT FROM AUTHOR]

Copyright of Herz is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)