We examined thirty methicillin-resistant Staphylococcus haemolyticus isolates cultured from clinical specimens for antibiotic resistance, various important interactions of the bacteria with epithelial cells and putative virulence determinants. All strains were resistant to oxacillin and carried the mecA gene. Aminocyclitol-3′-phosphotransferase (aph(3′)-IIIa) gene encoding nucleotidyltransferases was detected in 43 %, aminocyclitol-6′-acetyltransferase-aminocyclitol-2″-phosphotransferase (aac(6′)/aph(2″)) gene encoding bifunctional acetyltransferases/phosphotransferases in 33 %, aminocyclitol-4′-adenylyltransferase (ant(4′)-Ia) gene encoding phosphotransferases in 20 %. The coexistence of resistance to methicillin and aminoglycosides was investigated in multi-resistant strains. Coexisting (aac(6′)/aph(2″)) and (aph(3′)-IIIa) genes were detected in 33 % of isolates, whereas 63 % of isolates had at least one of these genes. All strains revealed adherence ability and most of them (63 %) were invasive to epithelial cells. Electron microscopy revealed that the bacteria were found in vacuoles inside the cells. We observed that the contact of the bacteria with host epithelial cells is a prerequisite to their cytotoxicity at 5 h-incubation. Culture supernatant of the strains induced a low effect of cytotoxicity at the same time of incubation. Cell-free supernatant of all isolates expressed cytotoxic activity which caused destruction of HEp-2 cells at 24 h. None of the strains was cytotonic towards CHO cells. Among thirty strains, 27 % revealed lipolytic activity, 43 % produced lecithinase and 20 % were positive for proteinase activity. Analyses of cellular morphology and DNA fragmentation exhibited typical characteristic features of those undergoing apoptosis. The Pearson linear test revealed positive correlations between the apoptotic index at 24 h and percentage of cytotoxicity. Our results provided new insights into the mechanisms contributing to the development of S. haemolyticus-associated infections. The bacteria adhered and invaded to non-professional phagocytes. The invasion of epithelial cells by S. haemolyticus could be similar to phagocytosis that requires polymerization of the actin cytoskeleton. The process is inhibited by cytochalasin D. Moreover, they survived within the cells by residing in membrane bound compartments and induced apoptotic cell death.
The problem of enclaves/enclaves in the theory of ir opens an interesting field of study, not only because of the actual phenomena and processes accompanying the formation of said entities, but also due to inaccuracies and variances in the very terms in use, especially in the field of public policy. The Kaliningrad oblast is either an enclave (from the point of view of the EU, nATo, as well as Poland and Lithuania), or an exclave (from the point of view of the russian Federation). The status of the region as perceived by the Western countries and organisations differs from the russian standpoint. The Kaliningrad oblast always would be a region of external influences of the West, an element of their foreign, security and economic policies, while for russia Kaliningrad is a sphere of its domestic governance, although shaped by many international determinants resulting from its geographical location. This paper is aimed at examining public policy of the EU and neighbouring countries towards the Kaliningrad oblast in the context of its specific geographical location and legal status. Possibilities of the region's incorporation in the EU's neighbourhood is also emphasized in the paper as an important factor affecting the position of the Kaliningrad oblast.
The Lithuanian historiography is not a novelty in Polish academic literature. The attempts undertaken many times by historians to examine the Lithuanian past are fully justied by the common history of the Polish and Lithuanian lands. It is worth stressing that there are still many controversial questions in this area, which have not been answered in both Lithuanian and Polish academic circles. Taking into account the basic facts from Lithuanian history in the 20th century, when Lithuanians undertook the first actions towards developing a state which would be offcially recognized by the international community, it should not be surprising that it is a subject frequently discussed by the newest studies, which continually refer to the equally rich literature of the earlier period. The researchers ascribe considerable signi!cance to the circumstances, in which the independent Lithuanian state came into being and to its functioning in the interwar period, in years 1918–1940 . What also had a strong influence on this process were the following events in the history of the state, when Lithuania was in the end incorporated into the Soviet Union.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.