Dimer and trimer procyanidins in Carignan and Mourvèdre grapes and red wines

Dimer procyanidins, galloylated or not, and trimers were analysed in the red grapes Carignan and Mourvedre. Procyanidins were extracted from the various parts of the grape bunch and then quantified by HPLC. In Carignan and Mourvedre grapes, procyanidin B2 was the major component in seeds, whereas procyanidin B1 was the major component in stems and skins. Trimeric procyanidins were also present in grapes in larger amounts. Various red wines were produced from Carignan and Mourvedre grapes, using different winemaking procedures: entire crushed harvest, destemmed harvest, carbonic maceration and heating of the harvest. Entire crushed harvest gave red wines with the highest levels of procyanidins. An important release of procyanidins, especially procyanidin B1 from skins and stems, when present, occurred.Procyanidines dimères et trimères des raisins et vins rouges de Carignan et MourvèdreDes procyanidines dimères galloylées et non-galloylées, et trimères sont dosées dans deux cépages rouges: Carignan et Mourvèdre. Les procyanidines sont extraites des différentes parties de la grappe puis quantifiées par CLHP en phase inverse. Dans le raisin de Carignan et de Mourvedre, la procyanidine B2 est la plus abondante dans les pepins, tandis que la procyanidine B1 est la plus abondante dans les rafles et pellicules. Les procyanidines trimères sont aussi présentes en quantités importantes. Différents vins rouges ont été élabores à partir des cépages Carignan et Mourvèdre, en utilisant plusieurs téchniques de vinification: vendange foulée; vendange éraflée, macération carbonique et le chauffage de la vendange. Les quantités les plus abondantes de procyanidines sont obtenues dans des vins issus d'une vendange entière et foulée

Genotypes and Toxin Gene Profiles of Staphylococcus aureus Clinical Isolates from China

A total of 108 S. aureus isolates from 16 major hospitals located in 14 different provinces in China were characterized for the profiles of 18 staphylococcal enterotoxin (SE) genes, 3 exfoliatin genes (eta, etb and etd), and the toxic shock syndrome toxin gene (tsst) by PCR. The genomic diversity of each isolate was also evaluated by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and accessory gene regulator (agr) typing. Of these strains, 90.7% (98/108) harbored toxin genes, in which tsst was the most prevalent toxin gene (48.1%), followed by sea (44.4%), sek (42.6%) and seq (40.7%). The see and etb genes were not found in any of the isolates tested. Because of high-frequency transfer of toxin gene-containing mobile genetic elements between S. aureus strains, a total of 47 different toxin gene combinations were detected, including a complete egc cluster in 19 isolates, co-occurrence of sea, sek and seq in 38 strains, and sec and sel together in 11 strains. Genetic typing by PFGE grouped all the strains into 25 clusters based on 80% similarity. MLST revealed 25 sequence types (ST) which were assigned into 16 clonal complexes (CCs) including 2 new singletons. Among these, 11 new and 6 known STs were first reported in the S. aureus strains from China. Overall, the genotyping results showed high genetic diversity of the strains regardless of their geographical distributions, and no strong correlation between genetic background and toxin genotypes of the strains. For genotyping S. aureus, PFGE appears to be more discriminatory than MLST. However, toxin gene typing combined with PFGE or MLST could increase the discriminatory power of genotyping S. aureus strains

A simple, portable, electrochemical biosensor to screen shellfish for vibrio parahaemolyticus

An earlier electrochemical mechanism of DNA detection was adapted and specified for the detection of Vibrio parahaemolyticus in real samples. The reader, based on a screen printed carbon electrode, was modified with polylactide-stabilized gold nanoparticles and methylene blue was employed as the redox indicator. Detection was assessed using a microprocessor to measure current response under controlled potential. The fabricated sensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0 × 10−8–2.0 × 10−13 M with a detection limit of 2.16 pM. The relative standard deviation for 6 replications of differential pulse voltammetry (DPV) measurement of 0.2 µM complementary DNA was 4.33%. Additionally, cross-reactivity studies against various other food-borne pathogens showed a reliably sensitive detection of the target pathogen. Successful identification of Vibrio parahaemolyticus (spiked and unspiked) in fresh cockles, combined with its simplicity and portability demonstrate the potential of the device as a practical screening tool

A pan-European ring trial to validate an International Standard for detection of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus in seafoods

Globally, vibrios represent an important and well-established group of bacterial foodborne pathogens. The European Commission (EC) mandated the Comite de European Normalisation (CEN) to undertake work to provide validation data for 15 methods in microbiology to support EC legislation. As part of this mandated work programme, merging of ISO/TS 21872–1:2007, which specifies a horizontal method for the detection of V. parahaemolyticus and V. cholerae, and ISO/TS 21872–2:2007, a similar horizontal method for the detection of potentially pathogenic vibrios other than V. cholerae and V. parahaemolyticus was proposed. Both parts of ISO/TS 21872 utilized classical culture-based isolation techniques coupled with biochemical confirmation steps. The work also considered simplification of the biochemical confirmation steps. In addition, because of advances in molecular based methods for identification of human pathogenic Vibrio spp. classical and real-time PCR options were also included within the scope of the validation. These considerations formed the basis of a multi-laboratory validation study with the aim of improving the precision of this ISO technical specification and providing a single ISO standard method to enable detection of these important foodborne Vibrio spp. To achieve this aim, an international validation study involving 13 laboratories from 9 countries in Europe was conducted in 2013. The results of this validation have enabled integration of the two existing technical specifications targeting the detection of the major foodborne Vibrio spp., simplification of the suite of recommended biochemical identification tests and the introduction of molecular procedures that provide both species level identification and discrimination of putatively pathogenic strains of V. parahaemolyticus by the determination of the presence of theromostable direct and direct related haemolysins. The method performance characteristics generated in this have been included in revised international standard, ISO 21872:2017, published in July 2017

Evaluation of quantitative PCR for early diagnosis of Pseudomonas aeruginosa infection in cystic fibrosis: a prospective cohort study

International audienc

Enterotoxigenic Potential of Staphylococcus intermedius

Staphylococcal food poisoning (SFP) caused by enterotoxigenic staphylococci is one of the main food-borne diseases. In contrast to Staphylococcus aureus, a systematic screening for the enterotoxins has not yet been performed on the genomic level for the coagulase-positive species S. intermedius. Therefore, the enterotoxigenic potential of 281 different veterinary (canine, n = 247; equine, n = 23; feline, n = 9; other, n = 2) and 11 human isolates of S. intermedius was tested by using a multiplex PCR DNA-enzyme immunoassay system targeting the staphylococcal enterotoxin genes sea, seb, sec, sed, and see. Molecular results were compared by in vitro testing of enterotoxin production by two immunoassays. A total of 33 (11.3%) S. intermedius isolates, including 31 (12.6%) canine isolates, 1 equine isolate, and 1 human isolate, tested positive for the sec gene. In vitro production of the respective enterotoxins was detected in 30 (90.9%) of these isolates by using immunological tests. In contrast, none of 65 veterinary specimen-derived isolates additionally tested and comprising 13 (sub)species of coagulase-negative staphylococci were found to be enterotoxigenic. This study shows on both molecular and immunological levels that a substantial number of S. intermedius isolates harbor the potential for enterotoxin production. Since evidence for noninvasive zoonotic transmission of S. intermedius from animal hosts to humans has been documented, an enterotoxigenic role of this microorganism in SFP via contamination of food products may be assumed