Identification of Salmonella for public health surveillance using whole genome sequencing.

In April 2015, Public Health England implemented whole genome sequencing (WGS) as a routine typing tool for public health surveillance of Salmonella, adopting a multilocus sequence typing (MLST) approach as a replacement for traditional serotyping. The WGS derived sequence type (ST) was compared to the phenotypic serotype for 6,887 isolates of S. enterica subspecies I, and of these, 6,616 (96%) were concordant. Of the 4% (n = 271) of isolates of subspecies I exhibiting a mismatch, 119 were due to a process error in the laboratory, 26 were likely caused by the serotype designation in the MLST database being incorrect and 126 occurred when two different serovars belonged to the same ST. The population structure of S. enterica subspecies II-IV differs markedly from that of subspecies I and, based on current data, defining the serovar from the clonal complex may be less appropriate for the classification of this group. Novel sequence types that were not present in the MLST database were identified in 8.6% of the total number of samples tested (including S. enterica subspecies I-IV and S. bongori) and these 654 isolates belonged to 326 novel STs. For S. enterica subspecies I, WGS MLST derived serotyping is a high throughput, accurate, robust, reliable typing method, well suited to routine public health surveillance. The combined output of ST and serovar supports the maintenance of traditional serovar nomenclature while providing additional insight on the true phylogenetic relationship between isolates.

Salmonella enterica serovar Enteritidis, England and Wales, 1945-2011.

In England and Wales, the emergence of Salmonella enterica serovar Enteritidis resulted in the largest and most persistent epidemic of foodborne infection attributable to a single subtype of any pathogen since systematic national microbiological surveillance was established. We reviewed 67 years of surveillance data to examine the features, underlying causes, and overall effects of S. enterica ser. Enteritidis. The epidemic was associated with the consumption of contaminated chicken meat and eggs, and a decline in the number of infections began after the adoption of vaccination and other measures in production and distribution of chicken meat and eggs. We estimate that >525,000 persons became ill during the course of the epidemic, which caused a total of 6,750,000 days of illness, 27,000 hospitalizations, and 2,000 deaths. Measures undertaken to control the epidemic have resulted in a major reduction in foodborne disease in England and Wales.

Mind-mindedness in parents of pre-schoolers: a comparison between clinical and community samples.

Mind-mindedness relates to parents' propensity to treat their young children as individuals with minds of their own. Research with community samples has demonstrated impressive findings regarding child development outcomes, leading to a suggestion that mind-mindedness should be considered in clinical interventions. This is the first mind-mindedness study to include parents of children referred to clinical services. A between group design (n=49) was used to investigate whether mind-mindedness differed between parents of a clinical group of pre-school children and parents of a community comparison group and to explore how mind-mindedness related to parental depression and stress, and child difficulties. The findings revealed that mind-mindedness was significantly lower in the clinical sample and was not related to depression in either group. In the clinical group mind-mindedness was related to parenting stress and in the community group it was related to children's emotional and behavioural difficulties. Overall these findings provide preliminary evidence that mind-mindedness may be an important construct to consider in pre-school clinical interventions.

A novel real-time polymerase chain reaction for identification of Salmonella enterica subspecies enterica.

Salmonella enterica subspecies enterica (subspecies I) causes the majority of infections in humans and homeothermic animals. We present a real-time polymerase chain reaction assay targeting the hilA gene that demonstrates 97.9% specificity and 99.9% sensitivity for rapid and reliable identification of subspecies I, offering savings in time and labor over traditional methods.

Rapid identification of Salmonella enterica subsp. arizonae and S. enterica subsp. diarizonae by real-time polymerase chain reaction.

Reptiles are popular as pets, leading to an increased risk of human infections due to uncommon Salmonella strains including the Arizona group (subspecies arizonae and diarizonae). We present a real-time Arizona-specific polymerase chain reaction demonstrating 100% specificity and 99.6% sensitivity, offering savings in time and labor over traditional identification methods.

Pulsed-field gel electrophoresis for molecular epidemiology of food pathogens.

Foodborne diseases due to well-recognized pathogens have emerged as an important and growing public health problem with a significant impact on health. Molecular methods for subtyping these microorganisms have become a valid adjunct to the traditional techniques employed in most laboratories. One such molecular technique for the detection and identification of food pathogens is pulsed-field gel electrophoresis (PFGE). This method separates large DNA molecules by the use of an alternating electrical field, such that greater size resolution can be obtained when compared to normal agarose gel electrophoresis. PFGE is often employed to track pathogens, such as Salmonella, Shigella, Escherichia coli (including O157), Campylobacter, and Listeria species through the food chain. The contour-clamped homogeneous electric field (CHEF) PFGE system is considered to be the gold standard for use in epidemiological studies of these organisms.

Potential of information technology in dental education.

The use of information technology (IT) in dentistry is far ranging. In order to produce a working document for the dental educator, this paper focuses on those methods where IT can assist in the education and competence development of dental students and dentists (e.g. e-learning, distance learning, simulations and computer-based assessment). Web pages and other information-gathering devices have become an essential part of our daily life, as they provide extensive information on all aspects of our society. This is mirrored in dental education where there are many different tools available, as listed in this report. IT offers added value to traditional teaching methods and examples are provided. In spite of the continuing debate on the learning effectiveness of e-learning applications, students request such approaches as an adjunct to the traditional delivery of learning materials. Faculty require support to enable them to effectively use the technology to the benefit of their students. This support should be provided by the institution and it is suggested that, where possible, institutions should appoint an e-learning champion with good interpersonal skills to support and encourage faculty change. From a global prospective, all students and faculty should have access to e-learning tools. This report encourages open access to e-learning material, platforms and programs. The quality of such learning materials must have well defined learning objectives and involve peer review to ensure content validity, accuracy, currency, the use of evidence-based data and the use of best practices. To ensure that the developers' intellectual rights are protected, the original content needs to be secure from unauthorized changes. Strategies and recommendations on how to improve the quality of e-learning are outlined. In the area of assessment, traditional examination schemes can be enriched by IT, whilst the Internet can provide many innovative approaches. Future trends in IT will evolve around improved uptake and access facilitated by the technology (hardware and software). The use of Web 2.0 shows considerable promise and this may have implications on a global level. For example, the one-laptop-per-child project is the best example of what Web 2.0 can do: minimal use of hardware to maximize use of the Internet structure. In essence, simple technology can overcome many of the barriers to learning. IT will always remain exciting, as it is always changing and the users, whether dental students, educators or patients are like chameleons adapting to the ever-changing landscape.

Flagellin gene sequence evolution in Salmonella.

Salmonella exhibits 70 serologically distinct flagellins, used internationally to diagnose and track infections. The terminal sequences of flagellin protein subunits are conserved in a range of bacteria and are here used as evolutionary markers to reveal how new serotypes arise. Terminal sequences of flagellins that exhibit factors g or m (G-group) were distinct from other Salmonella antigens (Non-G-group) and cluster more closely with Escherichia coli. It is postulated that G-group flagellins were inherited from a common ancestor of E. coli and Salmonella and that these antigens were among the original set in Salmonella. Sequence differences at the 5' termini may prevent recombination between co-infecting strains. Evidence of increased variation of flagellin in rare biphasic G-group serotypes suggests that the presence of a second flagellin locus allows mutation of the G-group flagellin. FljB probably arose from a single duplication of a Non-G gene, since which synonymous mutations resulted in the fljB-specific sequence at the 5' termini.

Towards the development of a DNA-sequence based approach to serotyping of Salmonella enterica.

BACKGROUND: The fliC and fljB genes in Salmonella code for the phase 1 (H1) and phase 2 (H2) flagellin respectively, the rfb cluster encodes the majority of enzymes for polysaccharide (O) antigen biosynthesis, together they determine the antigenic profile by which Salmonella are identified. Sequencing and characterisation of fliC was performed in the development of a molecular serotyping technique. RESULTS: FliC sequencing of 106 strains revealed two groups; the g-complex included those exhibiting "g" or "m,t" antigenic factors, and the non-g strains which formed a second more diverse group. Variation in fliC was characterised and sero-specific motifs identified. Furthermore, it was possible to identify differences in certain H antigens that are not detected by traditional serotyping. A rapid short sequencing assay was developed to target serotype-specific sequence motifs in fliC. The assay was evaluated for identification of H1 antigens with a panel of 55 strains. CONCLUSION: FliC sequences were obtained for more than 100 strains comprising 29 different H1 alleles. Unique pyrosequencing profiles corresponding to the H1 component of the serotype were generated reproducibly for the 23 alleles represented in the evaluation panel. Short read sequence assays can now be used to identify fliC alleles in approximately 97% of the 50 medically most important Salmonella in England and Wales. Capability for high throughput testing and automation give these assays considerable advantages over traditional methods.

Particulate inhalation during the removal of amalgam restorations.

An aerosol that contains amalgam particles is created when a high-speed hand-piece is used to remove an existing amalgam restoration. Those particles smaller than 10 microns are considered to be fully respirable. This means that a significant percentage of the particles have the potential to travel to the terminal alveoli, where they may become lodged. Long-term exposure to fully respirable particles may compromise a person's respiratory function. Amalgam restorations were placed in the typodont teeth of a mannequin designed to simulate the head and the respiratory tract of a patient. The amalgam restorations were removed under three experimental conditions: dry cut (control), wet cut (water spray) with high-velocity evacuation, and wet cut with high-velocity evacuation and a rubber dam. Particulate exposure was evaluated in the simulated respiratory tracts of the patient and the dentist that were equipped with ambient particle sizing samplers. Use of water spray and high-velocity evacuation significantly reduced patient exposure to particles. The use of a rubber dam, together with water spray and high-velocity evacuation, was responsible for a further significant reduction of exposure to particles when compared with water spray and high-velocity evacuation alone. The dentist, however, was exposed to moderate levels of fully respirable particles for all conditions tested. It is therefore recommended that all dental personnel wear face masks while removing existing amalgam restorations.

Gastrointestinal hormones and the quantitation of spontaneous duodenal motor activity.

This is a survey of the results of recent investigations on gastrointestinal (GI) peptide hormones. In addition to the classical GI hormones (secretin, gastrin, and cholecystokinin-pancreozymin (CCK-PZ], there are at least nine other peptides whose structures and GI effects are known. These include vasoactive intestinal polypeptide (VIP), gastric inhibitory polypeptide (GIP), motilin, pancreatic polypeptide (PP), substance P, neurotensin, somatostatin, enkephalins, and a bombesin-like gastrin-releasing peptide. It is now obvious that the traditional distinctions between hormones, neurotransmitters, and paracrines are rapidly becoming obsolete, as the actions and interactions of these substances within the complex motor system of the GI tract are gradually revealed. The study of perturbed states and toxic effects on the motor function of the small intestine is complicated by the integration of the activity of the small intestine with the activities of the body as a whole. A contemporary approach for evaluating intestinal contractile activity is described that uses computer assistance to measure the intercontractile interval (ICI). This technique may prove useful in assessing the effects of toxicological agents on spontaneous intestinal motor activity in vitro when the agents are delivered to the target sites by physiological mechanisms, in contrast to adding them to the tissue bath.

Comparison of the inhibitory effects of spermine, papaverine and adrenaline upon isolated segments of the rat small intestine.

In the rat isolated duodenal and ileal segments the active baseline force and spontaneous contractile frequency were inhibited by spermine; the relative potencies, estimated as an ED50, were adrenaline papaverine spermine. The changes in baseline force, but not frequency, due to spermine were sensitive to increased calcium. The duodenum was always more sensitive to papaverine and adrenaline, but the relative sensitivities of the duodenum and ileum were essentially equal for spermine. Inasmuch as the gastrointestinal mucosa of most species contains an abundance of polyamines, these results suggest that, in its free form, spermine may subserve a functional role in the inhibition of gastrointestinal motility.

LC50 values for rats acutely exposed to vapors of acrylic and methacrylic acid esters.

Acute exposure studies were conducted using adult male Sprague-Dawley rats to obtain LC50/24 concentrations for the common esters of acrylic and methacrylic acids. The order of acute toxicity was determined to be methyl acrylate greater than ethyl acrylate greater than butyl acrylate greater than butyl methacrylate greater than methyl methacrylate greater than ethyl methacrylate. Four-hour daily exposures (excluding weekends) of young adult male rats to 110 ppm methyl acrylate in air over a period of 32 d failed to produce significant differences in body or tissue weights, blood chemistries, gross metabolic performance, and spontaneous small-intestinal motor activities when compared with a sham-exposed group.

Mechanisms of the secretory and motor responses of the Brunner's gland region of the intestines to duodenal acidification.

The secretory and motor responses of the Brunner's gland region of the duodenum to luminal acidification were examined in rabbits anesthetized with urethan. Isomotic solutions of sodium chloride (pH 7.2) were perfused continuously through adjacent in situ segments. The pH of the perfusate of the proximal segment was changed to 2.0 for 30 min. Perfusion pressure (motor response) and volume and hexosamine concentration (secretory response) of the effluent were recorded for 3 h. The motor and secretory responses to luminal acidification were examined after intravenous (atropine) or intraluminal (lidocaine) pretreatment. Responses to intravenous infusions of serotonin or secretin were determined, also. Both atropine and lidocaine eliminated the initial motor and secretory responses of the proximal segment. Lidocaine eliminated the delayed secretory response of the distal segment. Serotonin caused initial motor and secretory responses, but secretin caused a delayed secretory response only. These results suggest that duodenal acidification elicits a two-phase increase in Brunner's gland secretion, the first being motor-dependent and the second motor-independent. The initial motor response was mediated by a local reflex composed of cholinergic and perhaps tryptaminergic receptors. The delayed secretory response was mediated by local and nonlocal, possibly hormonal, factors. Increased duodenal motility may provide a vehicle for the rapid expulsion of mucus, and thereby serve an important role in the function of the Brunner's glands.

Adrenergic control of somatostatin release.

The effects of adrenergic stimulation and suppression on somatostatin (SS), insulin, and glucagon release were studied in intact dogs. Isoproterenol, a beta-adrenergic agonist, significantly increased portal venous and arterial levels of SS and arterial levels of insulin and glucagon. Propranolol, a beta-adrenergic antagonist, significantly decreased portal venous SS and suppressed the isoproterenol-stimulated increases in the levels of SS, insulin, and glucagon. alpha-Adrenergic stimulation (propranolol plus epinephrine) decreased portal venous SS and arterial insulin. Phentolamine, and alpha-adrenergic antagonist, increased portal venous and arterial SS and arterial glucagon. These data suggest that in intact dogs, stimulation of beta-adrenergic receptors enhances the release of SS, insulin, and glucagon, while stimulation of alpha-adrenergic receptors inhibits the release of SS and insulin without having a definitive effect on glucagon.

Neural and hormonal control of Brunner's gland secretion.

For many years it has been speculated that the physiological function of Brunner's glands was to secrete mucus to protect the proximal duodenum from the corrosive effects of acidified gastric juice. However the control of Brunner's gland secretion remains an enigma. Some evidence exists which indicates both cholinergic and adrenergic innervation of these glands, but current consensus weighs heavily in favor of a hormonal stimulus for glandular secretion. This is based in part on evidence obtained from denervated Brunner's gland pouches following a feeding stimulus. a number of hormones and hormone-like substances have been investigated as possible mediators in this secretory response, however, no specificity was ever demonstrated. The inability to pinpoint a given substance as a common mediator can be attributed to the fact that most active agents employed also affect duodenal motility. We present evidence that Brunner's gland secretion can be observed to be a diphasic response. The initial, transient response is always observed in the presence of increased duodenal motility. The sustained response does not require duodenal motility and is probably hormonally mediated.