CD18-dependent activation of the neutrophil NADPH oxidase during phagocytosis of Escherichia coli or Staphylococcus aureus is regulated by class III but not class I or II PI3Ks

Phagocytosis and activation of the NADPH oxidase are important mechanisms by which neutrophils and macrophages engulf and kill microbial pathogens. We investigated the role of PI3K signaling pathways in the regulation of the oxidase during phagocytosis of Staphylococcus aureus and Escherichia coli by mouse and human neutrophils, a mouse macrophage-like cell line and a human myeloid-like cell line. Phagocytosis of these bacteria was promoted by serum, independent of serum-derived antibodies, and effectively abolished in mouse neutrophils lacking the beta(2)-integrin common chain, CD18. A combination of PI3K isoform-selective inhibitors, mouse knock-outs, and RNA-interference indicated CD18-dependent activation of the oxidase was independent of class I and II PI3Ks, but substantially dependent on the single class III isoform (Vps34). Class III PI3K was responsible for the synthesis of PtdIns( 3) P on phagosomes containing either bacteria. The use of mouse neutrophils carrying an appropriate knock-in mutation indicated that PtdIns(3) P binding to the PX domain of their p40(phox) oxidase subunit is important for oxidase activation in response to both S aureus and E coli. This interaction does not, however, account for all the PI3K sensitivity of these responses, particularly the oxidase response to E coli, suggesting that additional mechanisms for PtdIns( 3) P-regulation of the oxidase must exist. ( Blood. 2008; 112: 5202-5211)

Development and validation of dry reagent time-resolved fluoroimmuno assays for zeranol and alpha-zearalenol to assist in distinguishing zeranol abuse from Fusarium spp. toxin contamination in bovine urine

Zeranol, an oestrogenic growth promoter in food animals, is banned within the European Union (EU). However, commercially available immunoassay kits for zeranol cross-react with toxins formed by naturally occurring Fusarium spp. fungi, leading to false-positive screening results. This paper describes the validation of a specificity enhanced, rapid dry reagent time-resolved fluoroimmunoassay (TR-FIA) for zeranol (recovery 99%, limit of detection 1.3 ng ml(-1)) demonstrating that up to 150 ng ml(-1) of Fusarium spp. toxins in urine do not lead to false-positive results. This assay will assist EU Member States to implement Council Directive 961 23\EC, which requires states to monitor for potential abuses of zeranol. A similar TR-FIA for the Fusarium spp. toxin a-zearalenol, using the same sample extract, is also described (recovery 68%, limit of detection 5.6 ng ml(-1)). Only the addition of diluted sample extract is required to perform these dry-reagent TR-FIAs, the results being available within 1 h of extract application. The EU-funded project 'Natural Zeranol' (FAIR5-CT97-3443) will use these fluoroimmunoassays to screen bovine urine in four Member States to gather data on the seasonality of Fusarium spp. toxin contamination of urine and the incidence of zeranol screening test positives.

Antibacterial activities of naturally occurring compounds against antibiotic-resistant Bacillus cereus vegetative cells and spores, Escherichia coli, and Staphylococcus aureus

After demonstrating the lack of effectiveness of standard antibiotics against the acquired antibiotic resistance of Bacillus cereus (NCTC 10989), Escherichia coli (NCTC 1186), and Staphylococcus aureus (ATCC 12715), we showed that the following natural substances were antibacterial against these resistant pathogens: cinnamon oil, oregano oil, thyme oil, carvacrol, (S)-perillaldehyde, 3,4-dihydroxybenzoic acid (beta-resorcylic acid), and 3,4-dihydroxyphenethylamine (dopamine). Exposure of the three pathogens to a dilution series of the test compounds showed that oregano oil was the most active substance. The oils and pure compounds exhibited exceptional activity against B. cereus vegetative cells, with oregano oil being active at nanogram, per milliliter levels. In contrast, activities against B. cereus spores were very low. Activities of the test compounds were in the following approximate order: oregano oil > thyme oil approximate to carvacrol > cinnamon oil > perillaldehyde > dopamine > beta-resorcylic acid. The order of susceptibilities of the pathogens to inactivation was as follows: B. cereus (vegetative) much greater than S. aureus approximate to E. coli much greater than B. cereus (spores). Some of the test substances may be effective against antibiotic-resistant bacteria in foods and feeds.

Behaviour of Brent geese Branta bernicla hrota and wigeon Anas penelope feeding on intertidal Zostera spp

Mixed flocks of pale-bellied Brent geese (Branta bernicla hrota) and wigeon (Anas penelope L.) feeding on intertidal Zostera spp were studied during October 1993 with respect to tidal position, feeding method and duration, and competitive: interactions within and between species. Owing to many disturbance incidents affecting the use of the site by wildfowl, only complete data on flow tides were presented. Brent geese fed over a greater period of the tidal cycle than wigeon. Differences in feeding methods indicated that Brent geese exploited the rhizomes, which are energetically more profitable than the shoot on which wigeon fed. Aggressive interactions were recorded within species but there were no records of aggression between species. More subtle competition for space, however, may have occurred during feeding. Brent geese could reach Zostera spp For a short period after increasing depth of water prevented access by wigeon. However, individual wigeon were observed foraging near feeding Brent geese, picking up the scraps oi material discarded by the latter, and small numbers of wigeon may benefit from the presence of the geese. These benefits for some individual wigeon are not considered to compensate for the disadvantages to the latter species population as a whole in feeding on poorer-quality food for a shorter period of the tidal cycle. This disadvantage is likely to have contributed to the decline in the wigeon population on Strangford Lough, Co. Down, while numbers of Brent geese have been maintained at a high level.

Infection-control strategies for preventing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in nursing homes for older people (Review)

Background: Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection control strategies are important in preventing and controlling MRSA transmission.

Objectives: The objective of this review was to determine the effects of infection control strategies for preventing the transmission of MRSA in nursing homes for older people.

Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2009, Issue 2), the Cochrane Wounds Group Specialised Register (searched May 29th, 2009). We also searched MEDLINE (from 1950 to May Week 4 2009), Ovid EMBASE (1980 to 2009 Week 21), EBSCO CINAHL (1982 to May Week 4 2009), British Nursing Index (1985 to May 2009), DARE (1992 to May 2009), Web of Science (1981 to May 2009), and the Health Technology Assessment (HTA) website (1988 to May 2009). Research in progress was sought through Current Clinical Trials (www.controlled-trials.com), Medical Research Council Research portfolio, and HSRPRoj (current USA projects). SIGLE was also searched in order to identify atypical material which was not accessible through more conventional sources.

Selection criteria: All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection control interventions in nursing homes for older people were eligible for inclusion.

Data collection and analysis: Two authors independently reviewed the results of the searches.

Main results: Since no studies met the selection criteria, neither a meta-analysis nor a narrative description of studies was possible.

Authors' conclusions: The lack of studies in this field is surprising. Nursing homes for older people provide an environment likely to promote the acquisition and spread of infection, with observational studies repeatedly reporting that being a resident of a nursing home increases the risk of MRSA colonisation. Much of the evidence for recently-issued United Kingdom guidelines for the control and prevention of MRSA in health care facilities was generated in the acute care setting. It may not be possible to transfer such strategies directly to the nursing home environment, which serves as both a healthcare setting and a resident's home. Rigorous studies should be conducted in nursing homes, to test interventions that have been specifically designed for this unique environment.

Resistance of Staphylococcus aureus to the cationic antimicrobial agent poly(2-(dimethylamino ethyl)methacrylate) (pDMAEMA) is influenced by cell-surface charge and hydrophobicity

Cationic antimicrobial agents may prevent device-associated infections caused by Staphylococcus epidermidis and Staphylococcus aureus. This study reports that the cationic antimicrobial polymer poly(2-(dimethylamino ethyl)methacrylate) (pDMAEMA) was more effective at antagonizing growth of clinical isolates of S. epidermidis than of S. aureus. Importantly, mature S. epidermidis biofilms were significantly inactivated by pDMAEMA. The S. aureus isolates tested were generally more hydrophobic than the S. epidermidis isolates and had a less negative charge, although a number of individual S. aureus and S. epidermidis clinical isolates had similar surface hydrophobicity and charge values. Fluorescence spectroscopy and flow cytometry revealed that fluorescently labelled pDMAEMA interacted strongly with S. epidermidis compared with S. aureus. S. aureus Delta dltA and Delta mprF mutants were less hydrophobic and therefore more susceptible to pDMAEMA than wild-type S. aureus. Although the different susceptibility of S. epidermidis and S. aureus isolates to pDMAEMA is complex, influenced in part by surface hydrophobicity and charge, these findings nevertheless reveal the potential of pDMAEMA to treat S. epidermidis infections.

COMPARATIVE ANALYSES OF THE NEUROPEPTIDE-F (NPF)-RELATED AND FMRFAMIDE-RELATED PEPTIDE (FARP)-IMMUNOREACTIVITIES IN FASCIOLA-HEPATICA AND SCHISTOSOMA SPP

Immunochemical techniques were used to determine the distribution, chemical characteristics and relative abundance of immunoreactivity (IR) to two native platyhelminth neuropeptides, neuropeptide F (NPF) (Moniezia expansa) and the FMRFamide-related peptide (FaRP), GNFFRFamide, in the trematodes, Fasciola hepatica and Schistosoma mansoni; the larger S. margrebowiei was used in the chemical analysis. Extensive immunostaining for the two peptides was demonstrated throughout the nervous systems of both F. hepatica and S. mansoni, with strong IR also in the innervation of muscular structures, including those associated with the egg-forming apparatus. The patterns of immunostaining were similar to those previously described for the vertebrate neuropeptide Y superfamily of peptides and for FMRFamide. Ultrastructurally, gold labelling of NPF- and GNFFRFamide-IRs was localized exclusively to the contents of secretory vesicles in the axons and somatic cytoplasm of neurones. Double-labelling experiments showed an apparent homogeneity of antigenic sites, in all probability due to the demonstrated cross-reactivity of the FaRP antiserum with NPF. Radioimmunoassay of acid-ethanol extracts of the worms detected 8.3 pmol/g and 4.7 pmol/g equivalents of NPF- and FMRFamide-IRs, respectively, for F. hepatica, and corresponding values of 4.9 pmol/g and 4.3 pmol/g equivalents for S. margrebowiei. Gel-permeation chromatography resolved IR to both peptides in discrete peaks and these eluted in similar positions to synthetic NPF (M. expansa) and GNFFRFamide, respectively.

Antimicrobial peptide incorporated poly(2-hydroxyethyl methacrylate) hydrogels for the prevention of Staphylococcus epidermidis-associated biomaterial infections

The effectiveness of the antimicrobial peptide maximin-4, the ultrashort peptide H-Orn-Orn-Trp-Trp-NH(2) , and the lipopeptide C(12) -Orn-Orn-Trp-Trp-NH(2) in preventing adherence of pathogens to a candidate biomaterial were tested utilizing both matrix- and immersion-loaded poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels. Antiadherent properties correlated to both the concentration released and the relative antimicrobial concentrations of each compound against Staphylococcus epidermidis ATCC 35984, at each time point. Immersion-loaded samples containing C(12) -Orn-Orn-Trp-Trp-NH(2) exhibited the lowest adherence profile for all peptides studied over 1, 4, and 24 h. The results outlined in this article show that antimicrobial peptides have the potential to serve as an important weapon against biomaterial associated infections. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.