Mutation and reassortment of highly pathogenic avian influenza A(H5N1) viruses at the animal–human interface remain a major concern for emergence of viruses with pandemic potential. To understand the ...relationship of H5N1 viruses circulating in poultry and those isolated from humans, comprehensive phylogenetic and molecular analyses of viruses collected from both hosts in Vietnam between 2003 and 2010 were performed. We examined the temporal and spatial distribution of human cases relative to H5N1 poultry outbreaks and characterized the genetic lineages and amino acid substitutions in each gene segment identified in humans relative to closely related viruses from avian hosts. Six hemagglutinin clades and 8 genotypes were identified in humans, all of which were initially identified in poultry. Several amino acid mutations throughout the genomes of viruses isolated from humans were identified, indicating the potential for poultry viruses infecting humans to rapidly acquire molecular markers associated with mammalian adaptation and antiviral resistance.
To test if biofilm formation in Staphylococcus epidermidis is dependent on the polysaccharide intercellular adhesin, whose biosynthesis is driven by the ica locus, a plasmid containing the ica locus ...was transferred to three ica-negative strains. Using in vitro biofilm assays and a rat central venous catheter infection model, we confirmed the importance of the ica locus for biofilm production and pathogenesis of S. epidermidis.
This paper presents an empirical study of the impacts of mobile termination rate (MTR) regulation on European mobile operator performance. It examines the effects of both glide path and asymmetric ...regulation on incumbents as well as new entrants to this market using a dynamic econometric model accounting for internal and cross performance effects. The study provides strong supportive evidence for current MTR regulation in Europe.
We designed a new set of primers for reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) to specifically amplify the HA gene of avian influenza viruses subtype H5N1. By testing ...nine H5N1 virus strains and 41 clinical samples collected in Northern Vietnam, we found that the new primers showed higher sensitivity and specificity than the previously published RT-LAMP primers and were comparable to the RT-PCR method currently recommended by WHO. These results suggest that our RT-LAMP assay may be a better choice as a diagnostic tool for current H5N1 influenza virus infection.
The agr quorum-sensing system in
Staphylococci controls the production of surface proteins and exoproteins. In the pathogenic species
Staphylococcus aureus, these proteins include many virulence ...factors. The extracellular signal of the quorum-sensing system is a thiolactone-containing peptide pheromone, whose sequence varies among the different staphylococcal strains. We demonstrate that a synthetic
Staphylococcus epidermidis pheromone is a competent inhibitor of the
Staphylococcus aureus agr system. Derivatives of the pheromone, in which the N-terminus or the cyclic bond structure was changed, were synthesized and their biological activity was determined. The presence of a correct N-terminus and a thiolactone were absolute prerequisites for an agr-activating effect in
S. epidermidis, whereas inhibition of the
S. aureus agr system was less dependent on the original structure. Our results show that effective quorum-sensing blockers that suppress the expression of virulence factors in
S. aureus can be designed based on the
S. epidermidis pheromone.
•No SARS-CoV-2 on inanimate surfaces was found.•Disinfectants may remove pathogens or significantly reduce SARS-CoV-2 contamination.•Good disinfection practices in healthcare facilities should be ...recommended.
The objective of the paper is to investigate the presence of SARS-CoV-2 on inanimate surfaces in four healthcare facilities treating patients with COVID-19 and four quarantine regiments of provincial military commands.
From August to October 2020, a total of 468 one-off environmental samples consisting of inanimate surfaces, garbage, and wastewater were collected. The real-time RT-PCR assay targeting E and RdRp genes to detect SARS-CoV-2 and checklist and questionnaire of disinfection practices were employed. If detected by RT-PCR, then positive samples are subjected to cell culture to determine viability.
The test results showed all samples (100%) to be negative with SARS-CoV-2 resulting in unperformed virus culture. As for recent disinfection practices, chlorine-based products dissolved at a concentration of 0.1% (1000 ppm) in the general context or 0.5% (5000 ppm) for blood and body fluid spills are routinely applied twice a day and at the discharge of patients or quarantined people.
The finding may illustrate the importance of disinfection practices in removing pathogens or significantly reducing SARS-CoV-2 contamination on environmental surfaces and waste.
This study analyses the evolutionary relatedness of 16 Japanese encephalitis virus (JEV) isolates (nine from Vietnam and seven from Japan) to previously published JEV strains using E gene sequence ...data. Vietnamese and Japanese strains isolated between 1986 and 1990 were found to cluster in genotype 3. However, more recent Vietnamese and Japanese strains isolated between 1995 and 2002 grouped within genotype 1, now a dominant though previously unreported genotype in Vietnam. In addition, in this study, strains isolated between 1995 and 2002 were more closely related to those isolated in the 1990s than to the older genotype 1 strains. Recently, the introduction of JEV genotype 1 into Japan and Korea has also been reported. Hence this genotype shift phenomenon may be occurring throughout all East Asia. Further studies on JEV ecology are needed to clarify the mechanism of JEV genotype 1 spread to new territories.
Understanding global influenza migration and persistence is crucial for vaccine strain selection. Using 240 new human influenza A virus whole genomes collected in Vietnam during 2001-2008, we looked ...for persistence patterns and migratory connections between Vietnam and other countries. We found that viruses in Vietnam migrate to and from China, Hong Kong, Taiwan, Cambodia, Japan, South Korea, and the United States. We attempted to reduce geographic bias by generating phylogenies subsampled at the year and country levels. However, migration events in these phylogenies were still driven by the presence or absence of sequence data, indicating that an epidemiologic study design that controls for prevalence is required for robust migration analysis. With whole-genome data, most migration events are not detectable from the phylogeny of the hemagglutinin segment alone, although general migratory relationships between Vietnam and other countries are visible in the hemagglutinin phylogeny. It is possible that virus lineages in Vietnam persisted for >1 year.
RWRWRW-NH2 (MP196) is an amphipathic hexapeptide that targets the bacterial cytoplasmic membrane and inhibits cellular respiration and cell wall synthesis. In previous studies it showed promising ...activity against Gram-positive bacteria and no significant cytotoxicity or hemolysis. MP196 is therefore used as lead structure for developing more potent antibiotic derivatives. Here we present a more comprehensive study on the parent peptide MP196 with regard to clinically relevant parameters. We found that MP196 acts rapidly bactericidal killing 97% of initial CFU within 10 min at two times MIC. We were unable to detect resistance in standard 24 and 48 h resistance frequency assays. However, MP196 was effective against some but not all MRSA and VISA strains. Serum binding of MP196 was intermediate and we confirmed its low toxicity against mammalian cell lines. MP196 did neither induce NFκB activation nor cause an increase in IL8 levels at 250 μg/mL, and no IgE-dependent activation of basophil granulocytes was detected at 500 μg/mL. Yet, MP196 demonstrated acute toxicity in mice upon injection into the blood stream. Phase contrast microscopy of mouse blood treated with MP196 revealed a shrinking of erythrocytes at 250 μg/mL and severe morphological changes and lysis of erythrocytes at 500 μg/mL. These data suggest that MP196 derivatization directed at further lowering hemolysis could be instrumental in overcoming acute toxicity. The assessment of hemolysis is a critical step in the evaluation of the clinical potential of promising antimicrobial peptides and should be accompanied by microscopy-based morphological analysis of blood cells.
The aim of this paper is to explore the effectiveness of asymmetric regulation, which allows a new mobile network operator to set higher termination rates than the incumbent operator. We assume that ...there are two market segments: one in which operators compete on equal terms, with a new technology, and the other in which the entrant is at a disadvantage since the technology it offers is inferior to the incumbent’s. Results show that asymmetric regulation can create favorable conditions that allow the entrant to strengthen its market positioning, and enhance consumer net utilities and social welfare. This highlights the importance of the degree of network asymmetry and the ways in which consumers are split between the two market segments. Lastly, we show that asymmetric regulation can create greater investment incentives for the entrant which could effectively enhance social welfare. These findings can provide useful insights for regulatory policy.
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