Establishment of transfusion-relevant bacteria reference strains for red blood cells.

Background And Objectives: Red blood cell concentrates (RBCC) are susceptible to bacterial contamination despite cold storage. A reliable evaluation of strategies to minimize the risk of RBCC-associated bacterial transmission requires the use of suitable reference bacteria. Already existing Transfusion-Relevant Bacteria Reference Strains (TRBRS) for platelet concentrates fail to grow in RBCC.

Microbiological Screening of Platelet Concentrates in Europe.

The risk of transfusion-associated sepsis due to transmission of bacteria is a persistent problem in the transfusion field. Despite numerous interventions to reduce the risk, cases of bacterial sepsis following transfusion are repeatedly being reported. Especially platelet concentrates are highly susceptible to bacterial contaminations due to the growth-promoting storage conditions.

Genome Sequences of the First WHO Repository of Platelet Transfusion-Relevant Bacterial Reference Strains.

To develop novel techniques for improving blood safety, dedicated bacterial strains, which are able to persist and to proliferate in blood platelet concentrates, are needed. Here, we present draft genome sequences of the four bacterial strains approved for the first WHO repository of platelet transfusion-relevant bacterial reference strains.

Glucose Augments Killing Efficiency of Daptomycin Challenged Staphylococcus aureus Persisters.

Treatment of Staphylococcus aureus in stationary growth phase with high doses of the antibiotic daptomycin (DAP) eradicates the vast majority of the culture and leaves persister cells behind. Despite resting in a drug-tolerant and dormant state, persister cells exhibit metabolic activity which might be exploited for their elimination. We here report that the addition of glucose to S.

Sodium polyanethol sulfonate (SPS) falsifies protein staining and quantification and how to solve this problem.

Sodium polyanethol sulfonate (SPS) is an anionic detergent with a broad range of activities and applications. While studying the excretion of cytoplasmic proteins in Staphylococcus aureus SPS was used as cell lysis inhibitor. When investigating the protein pattern of culture supernatants from cells grown in the absence or presence of SPS by Coomassie blue stained polyacrylamide gel the amount of protein bands was significantly decreased in the presence of SPS, suggesting that this effect was due to inhibition of cell lysis.

Excretion of cytoplasmic proteins (ECP) in Staphylococcus aureus.

Excretion of cytoplasmic proteins (ECP) is a common physiological feature in bacteria and eukaryotes. However, how these proteins without a typical signal peptide are excreted in bacteria is poorly understood. We studied the excretion pattern of cytoplasmic proteins using two glycolytic model enzymes, aldolase and enolase, and show that their excretion takes place mainly during the exponential growth phase in Staphylococcus aureus very similar to that of Sbi, an IgG-binding protein, which is secreted via the Sec-pathway.

Excretion of cytosolic proteins (ECP) in bacteria.

Excretion of cytosolic proteins (ECP) has been reported in bacteria and eukaryotes. As none of the classical signal peptide (SP) dependent or SP-independent pathways could be associated with ECP, it has been also referred to as 'non-classical protein export'. When microbiologists first began to study this subject in 1990, mainly singular cytoplasmic proteins were investigated, such as GAPDH at the cell surface and in the supernatant of pathogenic streptococci or glutamine synthetase (GlnA) as a major extracellular protein in pathogenic mycobacteria.

Metabolic aspects of bacterial persisters.

Persister cells form a multi-drug tolerant subpopulation within an isogenic culture of bacteria that are genetically susceptible to antibiotics. Studies with different Gram negative and Gram positive bacteria have identified a large number of genes associated with the persister state. In contrast, the revelation of persister metabolism has only been addressed recently.

Metabolic and transcriptional activities of Staphylococcus aureus challenged with high-doses of daptomycin.

Treatment of stationary growth phase Staphylococcus aureus SA113 with 100-fold of the MIC of the lipopeptide antibiotic daptomycin leaves alive a small fraction of drug tolerant albeit genetically susceptible bacteria. This study shows that cells of this subpopulation exhibit active metabolism even hours after the onset of the drug challenge. Isotopologue profiling using fully (13)C-labeled glucose revealed de novo biosynthesis of the amino acids Ala, Asp, Glu, Ser, Gly and His.

An update on the molecular genetics toolbox for staphylococci.

Staphylococci are Gram-positive spherical bacteria of enormous clinical and biotechnological relevance. Staphylococcus aureus has been extensively studied as a model pathogen. A plethora of methods and molecular tools has been developed for genetic modification of at least ten different staphylococcal species to date.

Characterization of a mazEF toxin-antitoxin homologue from Staphylococcus equorum.

Toxin-antitoxin (TA) systems encoded in prokaryotic genomes fall into five types, typically composed of two distinct small molecules, an endotoxic protein and a cis-encoded antitoxin of ribonucleic or proteinaceous nature. In silico analysis revealed seven putative type I and three putative type II TA systems in the genome of the nonpathogenic species strain Staphylococcus equorum SE3. Among these, a MazEF system orthologue termed MazEF(seq) was further characterized.