Selective Infection of Antigen-Specific B Lymphocytes by Salmonella Mediates Bacterial Survival and Systemic Spreading of Infection

Background: The bacterial pathogen Salmonella causes worldwide disease. A major route of intestinal entry involves M cells, providing access to B cell-rich Peyer's Patches. Primary human B cells phagocytose Salmonella typhimurium upon recognition by the specific surface Ig receptor (BCR). As it is unclear how Salmonella disseminates systemically, we studied whether Salmonella can use B cells as a transport device for spreading. Methodology/Principal Findings: Human primary B cells or Ramos cell line were incubated with GFP-expressing Salmonella. Intracellular survival and escape was studied in vitro by live cell imaging, flow cytometry and flow imaging. HEL-specific B cells were transferred into C57BL/6 mice and HEL-expressing Salmonella spreading in vivo was analyzed investigating mesenteric lymph nodes, spleen and blood. After phagocytosis by B cells, Salmonella survives intracellularly in a non-replicative state which is actively maintained by the B cell. Salmonella is later excreted followed by reproductive infection of other cell types. Salmonella-specific B cells thus act both as a survival niche and a reservoir for reinfection. Adoptive transfer of antigen-specific B cells before oral infection of mice showed that these B cells mediate in vivo systemic spreading of Salmonella to spleen and blood. Conclusions/Significance: This is a first example of a pathogenic bacterium that abuses the antigen-specific cells of the adaptive immune system for systemic spreading for dissemination of infection. \ua9 2012 Souwer et al

Human resources issues and Australian Disaster Medical Assistance Teams: results of a national survey of team members

Background: Calls for disaster medical assistance teams (DMATs) are likely to continue in response to international disasters. As part of a national survey, this study was designed to evaluate Australian DMAT experience in relation to the human resources issues associated with deployment.\ud \ud Methods: Data was collected via an anonymous mailed survey distributed via State and Territory representatives on the Australian Health Protection Committee, who identified team members associated with Australian DMAT deployments from the 2004 South East Asian Tsunami disaster.\ud \ud Results: The response rate for this survey was 50% (59/118). Most personnel had deployed to the Asian Tsunami affected areas with DMAT members having significant clinical and international experience. While all except one respondent stated they received a full orientation prior to deployment, only 34% of respondents (20/59) felt their role was clearly defined pre deployment. Approximately 56% (33/59) felt their actual role matched their intended role and that their clinical background was well suited to their tasks. Most respondents were prepared to be available for deployment for 1 month (34%, 20/59). The most common period of notice needed to deploy was 6–12 hours for 29% (17/59) followed by 12–24 hours for 24% (14/59). The preferred period of overseas deployment was 14–21 days (46%, 27/59) followed by 1 month (25%, 15/59) and the optimum shift period was felt to be 12 hours by 66% (39/59). The majority felt that there was both adequate pay (71%, 42/59) and adequate indemnity (66%, 39/59). Almost half (49%, 29/59) stated it was better to work with people from the same hospital and, while most felt their deployment could be easily covered by staff from their workplace (56%, 33/59) and caused an inconvenience to their colleagues (51%, 30/59), it was less likely to interrupt service delivery in their workplace (10%, 6/59) or cause an inconvenience to patients (9%, 5/59). Deployment was felt to benefit the affected community by nearly all (95%, 56/59) while less (42%, 25/59) felt that there was a benefit for their own local community. Nearly all felt their role was recognised on return (93%, 55/59) and an identical number (93%, 55/59) enjoyed the experience. All stated they would volunteer again, with 88% strongly agreeing with this statement.\ud \ud Conclusions: This study of Australian DMAT members provides significant insights into a number of human resources issues and should help guide future deployments. The preferred 'on call' arrangements, notice to deploy, period of overseas deployment and shift length are all identified. This extended period of operations needs to be supported by planning and provision of rest cycles, food, temporary accommodation and rest areas for staff. The study also suggests that more emphasis should be placed on team selection and clarification of roles. While the majority felt that there was both adequate pay and adequate indemnity, further work clarifying this, based on national conditions of service should be, and are, being explored currently by the state based teams in Australia. Importantly, the deployment was viewed positively by team members who all stated they would volunteer again, which allows the development of an experienced cohort of team members

Distribution and Genetic Profiles of Campylobacter in Commercial Broiler Production from Breeder to Slaughter in Thailand

Poultry and poultry products are commonly considered as the major vehicle of Campylobacter infection in humans worldwide. To reduce the number of human cases, the epidemiology of Campylobacter in poultry must be better understood. Therefore, the objective of the present study was to determine the distribution and genetic relatedness of Campylobacter in the Thai chicken production industry. During June to October 2012, entire broiler production processes (i.e., breeder flock, hatchery, broiler farm and slaughterhouse) of five broiler production chains were investigated chronologically. Representative isolates of C. jejuni from each production stage were characterized by flaA SVR sequencing and multilocus sequence typing (MLST). Amongst 311 selected isolates, 29 flaA SVR alleles and 17 sequence types (STs) were identified. The common clonal complexes (CCs) found in this study were CC-45, CC-353, CC-354 and CC-574. C. jejuni isolated from breeders were distantly related to those isolated from broilers and chicken carcasses, while C. jejuni isolates from the slaughterhouse environment and meat products were similar to those isolated from broiler flocks. Genotypic identification of C. jejuni in slaughterhouses indicated that broilers were the main source of Campylobacter contamination of chicken meat during processing. To effectively reduce Campylobacter in poultry meat products, control and prevention strategies should be aimed at both farm and slaughterhouse levels

Voor een betere bijengezondheid : Ondersteuning bijengezondheidscoördinatoren door bijen@wur

Bijen@wur zou het liefst zien dat elk jaar 80-90% van de bijenhouders geen volken verliest in de winter.4 Daarmee zouden we dan naar schatting uitkomen op een totale wintersterfte van ongeveer 5% of nog iets lager (Figuur 1) en zou er van elke twintig volken die we hebben, steeds maar één de winter niet uit komen. Helemaal geen wintersterfte is een onrealistisch streven. Als sector hebben we ook te maken met onervaren bijenhouders die nog in een leerproces zitten. Ook schat een bijenhouder een grensgeval wel eens verkeerd in of komen we onvoorziene omstandigheden tegen

Fysisch-chemische inductie van plantweerbaarheid

In dit rapport wordt verslag gedaan van onderzoek naar de interactie tussen rood/verrood-LED-stuurlicht en inductie van plantweerbaarheid middels elicitors. Het onderzoek bestond uit een reeks min of meer uniforme kasexperimenten uitgevoerd met groepen van jonge tomatenplanten als modelgewas, aangevuld met gerbera en enkele perkplanten als sierteeltgewassen. Het beoogde weerbaarheidseffect betrof het zogenoemde systemic acquired resistance (SAR). De effecten van de behandelingen werden vastgesteld door bepaling van salicylzuur, van expressie van pathogenesis related (PR) proteins, en van de meeldauwontwikkeling

Development of an on-site LAMP assay for identification of Thaumatotibia leucotreta and Helicoverpa armigera larvae on rose

Current phytosanitary (import) measures for the false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae) and the cotton bollworm moth Helicoverpa armigera (Lepidoptera: Noctuidae), do not provide protection to countries located in southern and central portions of the European Union (EU). Only glasshouses in northern parts of the EU benefit from EU wide phytosanitary regulation. The primary pathway for introduction of T. leucotreta and H. armigera into glasshouses in northern parts of the EU is via the import of cut flowers such as roses and to a lesser extent natural spread or migration. A limitating factor to the management and control of T. leucotreta and H. armigera is accurate identification. The aim of this study was to develop a loop mediated isothermal amplification (LAMP) assay for specific identification of T. leucotreta and H. armigera

Development and evaluation of a triplex TaqMan assay and Next Generation Sequence Analysis for improved detection of Xylella in plant material

Xylella fastidiosa is a heterogenous gram-negative bacterial plant pathogen with a wide host range covering over 300 plant species. Since 2013, in Europe, the presence of the pathogen is increasing in a part of the Mediterranean area, but causes in particular severe disease problems in olive orchards in the Southern part of Italy. Various subspecies of the pathogen were also diagnosed in natural outbreaks and intercepted ornamental plants in Europe, among them Olea europaea, Coffea arabica and Nerium oleander. The host range of the pathogen can vary, depending on the subspecies and even the strain. The availability of fast and reliable diagnostic tools are indispensable in management strategies to control diseases caused by X. fastidiosa. To improve the reliability of the TaqMan assay, currently widely used in surveys, a triplex TaqMan assay was developed in which two specific and sensitive TaqMan assays, previously designed for X. fastidiosa, were combined with an internal control. The triplex assay exhibited the same diagnostic sensitivity as the simplex assays. In addition, the usefulness of a metagenomic approach using next generation sequencing (NGS) was demonstrated, in which total DNA extracted from plant material was sequenced. DNA extracts from plant material free of X. fastidiosa, from artificially inoculated hosts plants or from naturally infected plants sampled in France, Spain and Italy, or intercepted in Austria and The Netherlands, were analysed for the presence of X. fastidiosa using the metagenomic approach. In all samples, even in samples with a low infection level, but not in the pathogen-free samples, DNA reads were detected specific for X. fastidiosa. In most cases, the pathogen could be identified up to the subspecies level and for one sample even the whole genome could be assembled and the sequence type could be determined. All results of NGS analysed samples were confirmed with the triplex TaqMan PCR and LAMP

Development and evaluation of a triplex TaqMan assay and Next Generation Sequence Analysis for improved detection of Xylella in plant material

Xylella fastidiosa is a heterogenous gram-negative bacterial plant pathogen with a wide host range covering over 300 plant species. Since 2013, in Europe, the presence of the pathogen is increasing in a part of the Mediterranean area, but causes in particular severe disease problems in olive orchards in the Southern part of Italy. Various subspecies of the pathogen were also diagnosed in natural outbreaks and intercepted ornamental plants in Europe, among them Olea europaea, Coffea arabica and Nerium oleander. The host range of the pathogen can vary, depending on the subspecies and even the strain. The availability of fast and reliable diagnostic tools are indispensable in management strategies to control diseases caused by X. fastidiosa. To improve the reliability of the TaqMan assay, currently widely used in surveys, a triplex TaqMan assay was developed in which two specific and sensitive TaqMan assays, previously designed for X. fastidiosa, were combined with an internal control. The triplex assay exhibited the same diagnostic sensitivity as the simplex assays. In addition, the usefulness of a metagenomic approach using next generation sequencing (NGS) was demonstrated, in which total DNA extracted from plant material was sequenced. DNA extracts from plant material free of X. fastidiosa, from artificially inoculated hosts plants or from naturally infected plants sampled in France, Spain and Italy, or intercepted in Austria and The Netherlands, were analysed for the presence of X. fastidiosa using the metagenomic approach. In all samples, even in samples with a low infection level, but not in the pathogen-free samples, DNA reads were detected specific for X. fastidiosa. In most cases, the pathogen could be identified up to the subspecies level and for one sample even the whole genome could be assembled and the sequence type could be determined. All results of NGS analysed samples were confirmed with the triplex TaqMan PCR and LAMP

Monascus ruber as cell factory for lactic acid production at low pH

A Monascus ruber strain was isolated that was able to grow on mineral medium at high sugar concentrations and 175 g/l lactic acid at pH 2.8