Trend analysis of antimicrobial resistance in Campylobacter jejuni and Campylobacter coli isolated from Belgian pork and poultry meat products using surveillance data of 2004-2009

The purpose of this study was to analyze and compare antimicrobial resistance in Campylobacter spp. isolated from pork and poultry carcasses and pork and poultry meat(at slaughterhouse level, during meat cutting and at retail) in Belgium, using available surveillance data over the period 2004-2009. The susceptibilities of 1724 Campylobacter isolates for ampicillin, ciprofloxacin, nalidixic acid, tetracycline, erythromycin and gentamicin were tested by E-test. Gentamicin resistance was low (near 0%) till 2007, with an increase to over 20% by 2009 for all species-matrix combinations. Resistance to tetracycline fluctuated around the same level during the entire study period and was significantly higher (p-value <0.05) in C. coli than in C. jejuni. Erythromycin resistance was low and showed a slight decrease between 2004 and 2007, but increased from 2007 till 2009. Fluoroquinolone and ampicillin resistance was significantly higher in isolates derived from poultry, compared to pork-related isolates. This correlates with the higher use of these antimicrobials in poultry husbandry. With one out of four, C. coli from poultry showed the most apparent multiresistance (resistance to four or more antimicrobials). Approximately 1% of the poultry-derived isolates (both C. coli and C. jejuni) showed resistance to all tested antimicrobials, while none was found in pork product

Application of a strain- level shotgun metagenomics approach on food samples : resolution of the source of a Salmonella food-borne outbreak

Food- borne outbreak investigation currently relies on the time- consuming and challenging bacterial isolation from food, to be able to link food- derived strains to more easily obtained isolates from infected people. When no food isolate can be obtained, the source of the outbreak cannot be unambiguously determined. Shotgun metagenomics approaches applied to the food samples could circumvent this need for isolation from the suspected source, but require downstream strain- level data analysis to be able to accurately link to the human isolate. Until now, this approach has not yet been applied outside research settings to analyse real food- borne outbreak samples. In September 2019, a Salmonella outbreak occurred in a hotel school in Bruges, Belgium, affecting over 200 students and teachers. Following standard procedures, the Belgian National Reference Center for human salmonellosis and the National Reference Laboratory for Salmonella in food and feed used conventional analysis based on isolation, serotyping and MLVA (multilocus variable number tandem repeat analysis) comparison, followed by wholegenome sequencing, to confirm the source of the contamination over 2 weeks after receipt of the sample, which was freshly prepared tartar sauce in a meal cooked at the school. Our team used this outbreak as a case study to deliver a proof of concept for a short- read strain- level shotgun metagenomics approach for source tracking. We received two suspect food samples: the full meal and some freshly made tartar sauce served with this meal, requiring the use of raw eggs. After analysis, we could prove, without isolation, that Salmonella was present in both samples, and we obtained an inferred genome of a Salmonella enterica subsp. enterica serovar Enteritidis that could be linked back to the human isolates of the outbreak in a phylogenetic tree. These metagenomics- derived outbreak strains were separated from sporadic cases as well as from another outbreak circulating in Europe at the same time period. This is, to our knowledge, the first Salmonella food- borne outbreak investigation uniquely linking the food source using a metagenomics approach and this in a fast time frame

Immunohistochemical cross-reactivity and electrophoretic comigration between calbindin D-27 kDa and visinin.

Calbindin D-27 kDa (previously named vitamin D-CaBP or cholecalcin) and visinin present similitude both for their purification procedure and histochemical localization. We systematically compared by histochemistry calbindin and visinin immunoreactive structures in chick and pigeon retina, in rat cerebellum and kidney and in pigeon cerebellum. The calbindin and visinin immunoreactive structures were identical except in the retina. Preabsorption of anti-visinin with purified chick or rat calbindin suppresses the labelling in every organ studied except in the photoreceptor layer of pigeon and chick retina. Such a persistence of labelling was explained by Western blotting analysis of chick-retina soluble proteins showing a pattern of 7 different proteins recognized by anti-visinin even though only one protein was recognized in rat kidney and cerebellum. Anti-visinin is thus a polyclonal antibody reacting with more than one antigen of the chick retina, one of those antigens being calbindin. Calbindin is the single antigen recognized by anti-visinin in the other tested organs. In conclusion, we present evidence that visinin is a calbindin.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Calbindin and calretinin localization in retina from different species.

Calbindin-D28K and calretinin are homologous calcium-binding proteins localized in many neurons of the central nervous systems. We have compared polyclonal antibodies against calbindin and calretinin and have shown by western blots using purified calbindin and calretinin from rat that (1) anti-calretinin does not recognize calbindin and (2) anti-calbindin presents some cross-reactivity with calretinin. In this report, we have compared by immunohistochemistry the localization of both calcium-binding proteins in the retina of monkey, pig, sheep, rat, cat, pigeon, and salamander. These results are compared with previous data for chick. There are many differences between species and not within species, but some aspects of the distribution are conserved. All species, except rat and monkey, have some cones which contain calbindin only. Most species also have some bipolar cells containing calbindin only. Calretinin is rarely seen in photoreceptors or bipolar cells. All species have horizontal cells which contain calretinin or calbindin or both. All species have amacrine cells and ganglion cells containing one or other protein. In the cat ganglion cell layer, the calretinin antisera define a new, asymmetric, type of cell.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Etude comparative de diff rentes m thodes permettant la culture en masse d'hybridomes et la production optimis e d'anticorps monoclonaux

SIGLEBSE B226168Y / UCL - Université Catholique de LouvainBEBelgiu

Synthesis and pharmacological evaluation of a new targeted drug carrier system: β-Cyclodextrin coupled to oxytocin

β-Cyclodextrin (β-CD) was monofunctionalized into its carboxylic derivative and then conjugated to the N-side of oxytocin (OT), a nonapeptide involved in human behavior and myometrium contraction. On isolated rat myometrium, this conjugate (β-CD-OT) partly preserves the contracting activity of OT (EC50 = 0.40 μM vs 1.7 nM). Moreover, the contraction induced frequency is also lowered by β-CD-OT. This novel hydrophilic targeted carrier could form a host–guest complex with prostaglandins and their derivatives used as labor inducers or with anticancer drugs used in cervix and endometrial cancer. This strategy can improve the solubility, the stability, and/or the biological activity of these drugs as well as reducing their side-effects

Calcium binding protein immunoreactivity in pigeon retina.

Pigeon retina has been mapped immunocytochemically for vitamin D-dependent calcium-binding protein (D-CaBP). Immunoreactivity was found in the cones of the yellow field, but not in photoreceptors of the red field. The D-CaBP-containing cones were a subpopulation of those in the yellow field having straight fibres leading to their synaptic terminals. D-CaBP immunoreactivity was also found in horizontal cells, the amount present varying according to position along the retina, and in some amacrine cells. Immunoblots of pigeon retinal proteins separated by SDS-polyacrylamide gel electrophoresis indicated two D-CaBP forms, having apparent molecular weights of 27000 and 29000. Both these forms of D-CaBP have been found previously in rat and pigeon brain.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe