Fluorescence Single Particle Tracking for the Characterization of Submicron Protein Aggregates in Biological Fluids and Complex Formulations

To evaluate the potential of fluorescence single particle tracking (fSPT) for the characterization of submicron protein aggregates in human serum, plasma and formulations containing human serum albumin (HSA). A monoclonal IgG was covalently labeled with a fluorescent dye and cross-linked with glutaraldehyde. IgG aggregates and fluorescent beads of 0.1 mu m (control) were diluted in buffer, serum and plasma, and their size distributions were analyzed by fSPT and nanoparticle tracking analysis (NTA). In a separate experiment, IgG and HSA, fluorescently labeled with different dyes, were mixed and subjected to heat stress. The stressed sample was analyzed by fSPT using a dual color mode and by NTA. The accuracy and precision of fSPT proved to be comparable to NTA. fSPT was able to successfully measure all the samples in buffer, serum and plasma. The average size of the cross-linked protein aggregates showed a slight increase in biological fluids. Moreover, fSPT analysis showed that a significant proportion of the aggregates formed by subjecting an IgG/HSA mixture to heat stress were composed of both proteins. fSPT is a powerful technique for the characterization of submicron protein aggregates in biological fluids and complex formulations

Een cluster van invasieve meningokokkeninfectie 34045

Op 3 januari 2011 kregen twee vriendinnetjes van drie jaar uit eenzelfde klas in Vlaams-Brabant op bijna hetzelfde moment een invasieve meningokokkeninfectie. Zij werden in twee verschillende ziekenhuizen behandeld. Op school werd geen actie ondernomen omdat het contact met de klasgenootjes tien dagen geleden was. De kinderen werden mogelijk besmet door dezelfde persoon tijdens de kerstvakantie. Vier maanden later ontwikkelde een driejarig meisje uit dezelfde klas, samen met haar zusje van één jaar een invasieve meningokokkeninfectie bij hun aankomst in Caracas (Venezuela), waar ze op familiebezoek gingen. Het meisje van één jaar overleed. Zowel in het kinderdagverblijf van het eenjarige meisje als in de klas van het driejarige meisje in België werd chemoprofylaxe gegeven. Het laboratorium van het Nationaal Instituut voor Hygiëne in Venezuela bezorgde vijf DNA-extracties van de stammen van de twee zusjes aan het nationaal referentiecentrum voor Neisseria meningitidis van het Wetenschappelijk Instituut Volksgezondheid in Brussel. Uit moleculair onderzoek bleken de stammen uit Venezuela en de stammen uit België hoogstwaarschijnlijk klonaal verwant te zijn.</p

Het belang van Norovirus detectie bij collectieve gastro-enteritis uitbraken: van diagnose tot desinfectie van de besmettingshaard

Tijdens de maanden juli en augustus van 2010 kregen een aantal jeugdbewegingen in Vlaanderen te kampen met een Norovirus-infectie tijdens hun jaarlijkse zomerkamp. Hierbij werden minstens 180 personen ziek en 55 personen gehospitaliseerd. Onderzoek van de omgeving toonde aan dat voornamelijk gemeenschappelijke plaatsen zoals de sanitaire ruimten besmet waren met Norovirus en waarschijnlijk een belangrijke verspreidingshaard vormden voor Norovirus. Een snelle diagnose met daaropvolgend een adequate reiniging en desinfectie van de omgeving is belangrijk om secundaire Norovirusuitbraken te voorkomen.</p

Shigellosis outbreak linked to canteen-food consumption in a public institution: a matched case-control study36545

On 13 November 2009, the authorities of Flemish Brabant, Belgium, received an alert concerning a potential outbreak of Shigella sonnei at a public institution. A study was conducted to assess the extent, discover the source and to implement further measures. We performed a matched case-control study to test an association between shigellosis and canteen-food consumption. Water samples and food handlers&#039; faecal samples were tested. The reference laboratory characterized the retrospectively collected Shigella specimens. We found 52 cases distributed over space (25/35 departments) and time (2 months). We found a matched odds ratio of 3.84 (95% confidence interval 1.02-14.44) for canteen-food consumption. A food handler had travelled to Morocco shortly before detection of the first laboratory-confirmed case. Water samples and food handlers&#039; faecal samples tested negative for Shigella. Confirmed cases presented PFGE profiles, highly similar to archived isolates from Morocco. Foodborne transmission associated with the canteen was strongly suspected</p

Lessons learned from a textbook outbreak: EHEC-O157:H7 infections associated with the consumption of raw meat products, June 2012, Limburg, Belgium.

&lt;p&gt;&lt;b&gt;BACKGROUND: &lt;/b&gt;On 5 June 2012 several enterohemorrhagic Escherichia coli, EHEC, O157:H7 infections were reported to the public health authorities of Limburg.&lt;/p&gt;&lt;p&gt;&lt;b&gt;METHODS: &lt;/b&gt;We performed a case-control study, a trace back/forward investigation and compared strains isolated from human cases and food samples. A case was defined as anyone with a laboratory-confirmed E. coli O157:H7-infection in North-East Limburg from May 30 2012 till July 15 2012. Family members with bloody diarrhea were also included as cases. E. coli O157 was isolated by culture and the presence of the virulence genes was verified using (q)PCR. Isolates were genotyped and compared by Pulsed Field Gel Electrophoresis (PFGE) and insertion sequence 629-printing (IS629-printing).&lt;/p&gt;&lt;p&gt;&lt;b&gt;RESULTS: &lt;/b&gt;The outbreak involved 24 cases, of which 17 were laboratory-confirmed. Five cases developed Hemolytic Uremic Syndrome (HUS) and fifteen were hospitalized. Cases reported a significantly higher consumption of &quot;steak tartare&quot;, a raw meat product (OR 48.12; 95% CI; 5.62- 416.01). Cases were also more likely to buy meat-products at certain butcheries (OR 11.67; 95% CI; 1.41 - 96.49). PFGE and IS629-printing demonstrated that the vtx1a vtx2a eae ehxA positive EHEC O157:H7 strains isolated from three meat products and all seventeen human stool samples were identical. In a slaughterhouse, identified by the trace-back investigation, a carcass infected with a different EHEC strain was found and confiscated.&lt;/p&gt;&lt;p&gt;&lt;b&gt;CONCLUSION: &lt;/b&gt;We present a well described and effectively investigated foodborne outbreak associated with meat products. Our main recommendations are the facilitation and acceleration of the outbreak detection and the development of a communication plan to reaches all persons at risk.&lt;/p&gt;&lt;p&gt;&lt;b&gt;MESH: &lt;/b&gt;Foodborne diseases, Shiga-toxigenic Escherichia coli, Enterohemorrhagic Escherichia coli, Meat products, Case control studies, Electrophoresis, Gel, Pulsed-Field.&lt;/p&gt;</p

Whole-genome sequencing for TB source investigations: principles of ethical precision public health

Whole-genome sequencing (WGS) of allows rapid, accurate inferences about the sources, location and timing of transmission. However, in an era of heightened concern for personal privacy and science distrust, such inferences could result in unintended harm and undermine the public´s trust. We held interdisciplinary stakeholder discussions and performed ethical analyses of real-world illustrative cases to identify principles that optimise benefit and mitigate harm of WGS-driven TB source investigations. The speed and precision with which real-time WGS can be used to associate strains with sensitive information has raised important concerns. While detailed understanding of transmission events could mitigate harm to vulnerable patients and communities when otherwise unfairly blamed for TB outbreaks, the precision of WGS can also identify transmission events resulting in social blame, fear, discrimination, individual or location stigma, and the use of defaming language by the public, politicians and scientists. Public health programmes should balance the need to safeguard privacy with public health goals, transparency and individual rights, including the right to know who infects whom or where. Ethical challenges raised by real-time WGS-driven TB source investigation requires public health authorities to move beyond their current legal mandate and embrace transparency, privacy and community&nbsp;engagement.</p