International journal of medical microbiology : IJMM
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Rapid diagnosis of sepsis is of outstanding significance as each hour of delay of appropriate antimicrobial therapy increases mortality by 5-10%. As a result, antibiotics are started without a definitive microbial result based on clinical signs in concert with "biomarkers" with high sensitivity but a lack of specificity. Diagnostic uncertainty is compensated for by liberal use of broad spectrum antibiotics with inherent resistance as an increasing public-health problem. ⋯ Recent data from transcriptomic and/or proteomic profiling would, however, indicate that marker panels derived from transcriptomic or proteomic profiling are superior to single proteins to differentiate non-infectious from sepsis-associated systemic inflammation. Multiplexed assay systems, e.g. after platform transfer from whole-genomic chips to multiplexed quantitative PCR are currently being developed with potential to improve sensitivity and specificity. Clinical utility of both, molecular tests to identify the pathogen and the ensuing host response, has still to be evaluated in prospective trials.
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Int. J. Med. Microbiol. · Feb 2010
ReviewStaphylococcal lipoproteins and their role in bacterial survival in mice.
Staphylococcus aureus expresses about 50 lipoproteins (Lpp), which are lipid-anchored in the membrane. The processing of the precursor to the mature Lpp is catalyzed by the phosphatidyl glycerol diacylglyceryl transferase (Lgt) and the lipoprotein-specific type II signal peptidase (LspA) leading to diacylated Lpp. Possibly another acyltransferase attaches a third fatty acid leading to triacylated Lpp. ⋯ In the host, maturation of Lpp confers optimal metal ion - particularly iron - acquisition, it enhances staphylococcal invasion and phagocytosis, intracellular survival and persistence of infections. However, the advantages of Lpp maturation are counterbalanced by the capability to induce inflammation. In this review, we summarize the current knowledge about the role of Lpp in iron acquisition and TLR2 recognition in the host and describe the consequences of Lpp maturation for survival of S. aureus in the host.
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Int. J. Med. Microbiol. · Jan 2010
ReviewMolecular crosstalk of probiotic bacteria with the intestinal immune system: clinical relevance in the context of inflammatory bowel disease.
It is current knowledge that the intestinal microbiota plays a major role in the development and maintenance of intestinal health. Intestinal epithelial cells (IEC) constitute the interface between the gut lumen and the innate and adaptive immune system. To maintain intestinal homeostasis, the organized and diffuse compartments of the gut-associated lymphoid tissue have to process the continuously varying information at the interface between the luminal side and the host. ⋯ In contrast to the colitogenic effects of enteric bacteria, clinical and experimental studies showed that specific probiotic strains are protective in the context of chronic intestinal inflammation. Although the molecular understanding of bacteria-host interaction is improving, the anti-inflammatory mechanisms induced by these probiotic bacteria are just starting to be unraveled. The present review is meant to summarize and discuss the clinical relevance of probiotics, but it also seeks to give an overview about currently known probiotic mechanisms in the context of chronic intestinal inflammation with a focus on IEC.
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Int. J. Med. Microbiol. · Sep 2004
ReviewBacterial evasion of innate host defenses--the Staphylococcus aureus lesson.
Bacterial pathogens such as Staphylococcus aureus use highly efficient mechanisms to evade recognition and elimination by the innate immune system. S. aureus produces sophisticated anti-inflammatory molecules and it employs several mechanisms protecting the bacteria against host cationic antimicrobial molecules such as defensin-like peptides and bacteriolytic enzymes such as lysozyme. Cell wall teichoic acids and lipoteichoic acids, complex Gram-positive surface polymers, and modified membrane lipids such as lysylphosphatidylglycerol are crucial in defensin resistance and other important aspects of staphylococcal virulence such as nasal colonization and biofilm formation on biomaterials. Certain S. aureus genes conferring escape from innate host defenses are conserved in many human pathogens suggesting that the underlying mechanisms are of general significance in bacterial virulence.