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A simple two-step plasmachemical methodology is outlined for the fabrication of microcondensor surfaces. This comprises the creation of a superhydrophobic background followed by pulsed plasma deposition of a hydrophilic polymer array. Microcondensation efficiency has been explored in terms of the chemical nature of the hydrophilic pixels and their dimensions. These results are compared to the hydrophilic-hydrophobic pattern present on the Stenocara beetle's back, which is used by the insect to collect water in the desert. Potential applications include fog harvesting, microfluidics, and biomolecule immobilization.

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Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786) in Staphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determinants. In liquid culture, deletion of CcpA decreased the growth rate and yield; however, the effect was only transient during the exponential-growth phase as long as glucose was present in the medium. Depletion of glucose and production of lactate was delayed, while the level of excretion of acetate was less affected and was even higher in the mutant culture. On solid medium, in contrast, growth of the ⌬ccpA mutant resulted in smaller colonies containing a lower number of CFU per colony. Deletion of CcpA had an effect on the expression of important virulence factors of S. aureus by down-regulating RNAIII, the effector molecule of the agr locus, and altering the transcription patterns of hla, encoding ␣-hemolysin, and spa, encoding protein A. CcpA inactivation markedly reduced the oxacillin resistance levels in the highly methicillin-resistant S. aureus strain COLn and the teicoplanin resistance level in a glycopeptide-intermediateresistant S. aureus strain. The presence of CcpA in the capsular polysaccharide serotype 5 (CP5)-producing strain Newman abolished capsule formation and decreased cap operon transcription in the presence of glucose. The staphylococcal CcpA thus not only is involved in the regulation of carbon metabolism but seems to function as a modulator of virulence gene expression as well.Carbon catabolite repression (CCR) in bacteria is a widespread, global regulatory phenomenon that allows modulation of the expression of genes and operons involved in carbon utilization and metabolization in the presence of preferred carbon source(s). In CCR, the presence of a preferred carbon source represses the expression of genes and operons whose products are involved in the metabolism of alternative, lesspreferred carbon sources. In low-GC gram-positive bacteria, CCR is achieved via transcriptional control, inducer exclusion, and induction prevention (reviewed in references 55 and 60). In this group of bacteria, a common mechanism for transcriptional control has evolved that is mediated via the proteins phosphotransferase HPr, the bifunctional HPr kinase-phosphatase (HPrK/P), and the pleiotropic regulator CcpA (catabolite control protein A). CCR in Bacillus subtilis has been studied extensively and is thought to serve as the prototype of CCR-regulated gene expression in gram-positive organisms (reviewed in reference 52). In B. subtilis, regulation of transcription of catabolite-repressive genes is exerted mainly through the binding of CcpA to specific cis-acting DNA sequences called catabolite-responsive elements (CREs). The DNA-binding activity of CcpA itself is triggered by HPr or its regulatory paralog Crh, which, in the presence of glucose, are phosphorylated by HPrK/P on regulatory seryl residues, in which st...

The opportunistic pathogens Staphylococcus aureus and Staphylococcus epidermidis represent major causes of severe nosocomial infection, and are associated with high levels of mortality and morbidity worldwide. These species are both common commensals on the human skin and in the nasal pharynx, but are genetically distinct, differing at 24% average nucleotide divergence in 1,478 core genes. To better understand the genome dynamics of these ecologically similar staphylococcal species, we carried out a comparative analysis of 324 S. aureus and S. epidermidis genomes, including 83 novel S. epidermidis sequences. A reference pan-genome approach and whole genome multilocus-sequence typing revealed that around half of the genome was shared between the species. Based on a BratNextGen analysis, homologous recombination was found to have impacted on 40% of the core genes in S. epidermidis, but on only 24% of the core genes in S. aureus. Homologous recombination between the species is rare, with a maximum of nine gene alleles shared between any two S. epidermidis and S. aureus isolates. In contrast, there was considerable interspecies admixture of mobile elements, in particular genes associated with the SaPIn1 pathogenicity island, metal detoxification, and the methicillin-resistance island SCCmec. Our data and analysis provide a context for considering the nature of recombinational boundaries between S. aureus and S. epidermidis and, the selective forces that influence realized recombination between these species.

Staphylococcus epidermidis is a permanent member of the normal human microbiota, commonly found on skin and mucous membranes. By adhering to tissue surface moieties of the host via specific adhesins, S. epidermidis is capable of establishing a lifelong commensal relationship with humans that begins early in life. In its role as a commensal organism, S. epidermidis is thought to provide benefits to human host, including out-competing more virulent pathogens. However, largely due to its capacity to form biofilm on implanted foreign bodies, S. epidermidis has emerged as an important opportunistic pathogen in patients receiving medical devices. S. epidermidis causes approximately 20% of all orthopedic device-related infections (ODRIs), increasing up to 50% in late-developing infections. Despite this prevalence, it remains underrepresented in the scientific literature, in particular lagging behind the study of the S. aureus. This review aims to provide an overview of the interactions of S. epidermidis with the human host, both as a commensal and as a pathogen. The mechanisms retained by S. epidermidis that enable colonization of human skin as well as invasive infection, will be described, with a particular focus upon biofilm formation. The host immune responses to these infections are also described, including how S. epidermidis seems to trigger low levels of pro-inflammatory cytokines and high levels of interleukin-10, which may contribute to the sub-acute and persistent nature often associated with these infections. The adaptive immune response to S. epidermidis remains poorly described, and represents an area which may provide significant new discoveries in the coming years.

In order for Staphylococcus aureus to adhere to host extracellular matrix (ECM) substrates, it elicits a wide range of surface proteins. We have characterized a novel ϳ1.1-MDa protein in S. aureus, termed Ebh (for ECMbinding protein homologue), which has homology to other ECM-binding proteins. Ebh consists of several domains, including a large central region with 44 imperfect repeats of 126 amino acids. Expression analysis revealed ebh to be growth phase regulated and repressed by agr. A fragment of the central repeat region of Ebh was cloned, overexpressed, and used in ligand-binding studies to determine Ebh function. The recombinant protein was found to specifically bind human fibronectin. Ebh is produced during human infection since serum samples taken from patients with confirmed S. aureus infections were found to contain anti-Ebh antibodies. Localization studies revealed Ebh to be cell envelope associated and is proposed to form a specialized surface structure involved in cellular adhesion.Staphylococcus aureus is able to cause a wide range of different infections, such as endocarditis, arthritis, and septicemia (55). In order for S. aureus to colonize and disseminate through its host, the bacterium expresses an array of proteins which interact with molecules of the host extracellular matrix (ECM). These bacterial cell surface and extracellular proteins bind to a wide range of host proteins, such as fibronectin (Fn) (15,21,25,42), fibrinogen (Fg) (21,36,40,56), vitronectin (21), collagen (50), thrombospondin (18), bone sialoprotein (51), elastin (8), and von Willebrand factor (16), belying the ability of S. aureus to act as the etiological agent of a variety of pathologies. Fn is an adhesive glycoprotein found on the surface of mammalian cells and in serum (7). Previous studies have implicated staphylococcal Fn-binding proteins with adhesion to different cell types (1,23,37,38,47). Also, they bind Fn, which acts as an invasin, forming a bridge between S. aureus and an integrin on the surface of nonprofessional phagocytes (1,9,23,33,46,48). Most of the ligand-binding proteins that have previously been characterized are found associated with the cell wall and are known as microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) (13). The specific interactions that these adhesins undergo with the ECM, coupled with the fact that they are found on the surface of the cell, means that they may be useful targets for prophylaxis or therapy, e.g., as vaccine components, as targets for passive immunotherapy, or for novel antiadhesive strategies.Recently, the genomes of S. aureus strains N315 and Mu50 have been published (31), and determination of the genomes of five additional strains has either been done or is nearing completion. These studies have revealed the presence of many uncharacterized putative surface proteins. The two largest genes, ebhA and ebhB, encode putative proteins of ca. 722 and 421 kDa, respectively. EbhA shows homology to the major adhesin of Streptococcus defectivus, Emb, a p...