Publications by authors named "Marc Stevens"

Nisin resistance development is one of food safety challenges posed by Listeria monocytogenes, an important foodborne pathogen that causes human listeriosis. The GtcA flippase enzyme is functionally crucial in two separate pathways that glycosylate cell envelope wall teichoic acids (WTA) with N-acetylglucosamine (NAG) and lipoteichoic acids (LTA) with galactose, respectively. This study investigated phenotypic roles and molecular mechanisms underlying GtcA involvement in L.

View Article and Find Full Text PDF

Infectious laryngotracheitis (ILT) is a respiratory disease affecting chickens worldwide. Unlike many countries, Switzerland does not vaccinate against ILT. This study analysed ILT samples from 21 natural outbreaks in Switzerland using restriction fragment length polymorphism (RFLP) and multiple gene sequencing.

View Article and Find Full Text PDF

Methicillin-resistant (MRSA) is of major public health concern due to its resistance to multiple antibiotics. This resistance has been observed in various settings, including hospitals and communities, and has been detected in both animals and humans. Although peridomestic rat species ( spp.

View Article and Find Full Text PDF

Purpose: We aimed to characterise Yersinia enterocolitica from human clinical specimens in Switzerland using epidemiological, microbiological and whole-genome sequencing (WGS) data.

Methods: Isolates (n = 149) were collected between January 2019 and December 2023. Epidemiological data was noted and strains were characterized by biochemical and serological typing, antimicrobial susceptibility testing (AST), and WGS-based analysis.

View Article and Find Full Text PDF

A case of massive overdose of sustained release bupropion tablets is described. The patient presented with GCS 3, tachycardic and in vasoplegic shock. ECHO and EKG were initially normal.

View Article and Find Full Text PDF

We describe a case of Salmonella infection caused by a sucrose-fermenting Salmonella enterica Typhimurium sequence type 12 which acquired transposon CTnscr94 carrying the sucrose operon scrKYABR. Sucrose-fermenting Salmonella are particularly challenging for culture-based detection and may lead to failure to detect Salmonella in clinical samples.

View Article and Find Full Text PDF

Campylobacter is among the most frequent agents of bacterial gastroenteritis in Europe and is primarily linked to the consumption of contaminated food. The aim of this study was to assess genomic diversity and to identify antimicrobial resistance and virulence genes of 155 Campylobacter isolated from broiler carcasses (neck skin samples) in a large-scale Swiss poultry abattoir over a three-year period. Samples originated from broilers from three different types of farming systems (particularly animal-friendly stabling (PAFS), free-range farms, and organic farms).

View Article and Find Full Text PDF

The current study addresses the critical issue of growth in raw sausage/meat products leading to human infections, most commonly listeriosis, which is known for its high fatality rate. This research focuses on the isolation, identification, and screening of lactic acid bacteria from various meat and fish products in Switzerland. In total, 274 lactic acid bacteria strains were isolated from 30 different products and were screened for their ability to inhibit growth, with 51 isolates demonstrating anti- activity at 8 °C, 15 °C, 25 °C, and 37 °C.

View Article and Find Full Text PDF

Here we report the genome sequence of the florfenicol-resistant strain 90_2023 isolated from a raw-meat sausage (Finocchiona) imported from Italy to Switzerland. It has a genome of 2.75 Mbp and harbors 16 antimicrobial resistance genes, including A8, , and a truncated gene on a RepA_N plasmid.

View Article and Find Full Text PDF

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS) that causes substantial morbidity and diminished quality of life. Evidence highlights the central role of myeloid lineage cells in the initiation and progression of MS. However, existing imaging strategies for detecting myeloid cells in the CNS cannot distinguish between beneficial and harmful immune responses.

View Article and Find Full Text PDF

is an important agent of gastrointestinal disease in humans. While livestock, such as cattle, poultry, and pigs, are well-recognised animal reservoirs of , there is a lack of data on in edible frogs, even though frog meat is a popular food worldwide. In this study, 103 live edible Chinese frogs () were collected from wet markets throughout Hong Kong.

View Article and Find Full Text PDF

The bovine genital tract harbors a dynamic microbiome. Genital tract microbial communities in healthy animals have been characterized using next-generation sequencing methods showing that microbe compositions differ between the vagina and uterus, more so during the postpartum period. Pre-calving fecal and vaginal, and endometrial swabs at the different postpartum intervals were collected from dairy cows.

View Article and Find Full Text PDF

Game meat is becoming increasingly popular but may be contaminated with pathogenic bacteria such as Shiga toxin-producing Escherichia coli (STEC). STEC cause gastrointestinal illnesses including diarrhoea, haemorrhagic colitis (HC), and the haemolytic uremic syndrome (HUS). The aim of this study was to assess the occurrence of STEC in 92 meat samples from chamois (n = 2), red deer (n = 27), roe deer (n = 38), and wild boar (n = 25), from Switzerland and other European countries.

View Article and Find Full Text PDF

() accounts for serious public health and food safety problems owing to its stress resilience and pathogenicity. Based on their regulatory involvement in global gene expression events, cold-shock domain family proteins (Csps) are crucial in expression of various stress fitness and virulence phenotypes in bacteria. possesses three Csps (CspA, CspB, and CspD) whose regulatory roles in the context of the genetic diversity of this bacterium are not yet fully understood.

View Article and Find Full Text PDF

A protocol for the carbonylative synthesis of acyl amidines from aryl halides, amidines, and carbon monoxide catalyzed by Pd(0) is reported herein. Notably, carbon monoxide is generated ex situ from a solid CO source, and several productive palladium ligands were identified with complementary benefits and substrate scope. Furthermore, sequential one-pot, two-step protocols for the synthesis of 1,2,4-triazoles and 1,2,4-oxadiazoles via acyl amidine intermediates are reported.

View Article and Find Full Text PDF

infection is considered to be a neglected tropical disease with huge impact on human and animal health alike. Dairy production in sub-Saharan Africa (SSA) relies heavily on various animals such as cows, goats, and camels, depending on the region. causes mastitis and exhibits high prevalence in raw milk.

View Article and Find Full Text PDF

Chelonians are recognized as a source of human salmonellosis through direct contact or consumption of their meat. Freshwater turtles sold for food are widely available in wet markets in Asia. In this pilot study, 50 turtles belonging to three species were randomly sampled from wet markets throughout Hong Kong.

View Article and Find Full Text PDF

Staphylococcal food poisoning is a common food intoxication caused by staphylococcal enterotoxins. While growth of Staphylococcus aureus is not inhibited by the meat-curing agent nitrite, we hypothesize that nitrite has an influence on enterotoxin C (SEC) expression. We investigated the influence of 150 mg/l nitrite on SEC expression at mRNA and protein level in seven strains expressing different SEC variants.

View Article and Find Full Text PDF

Humans ingest many microorganisms, which may colonize and interact with the resident gut microbiota. However, extensive knowledge about host-independent microbe-microbe interactions is lacking. Here, we investigated such colonization process using a derivative of the model probiotic WCFS1 into continuously cultivated gut microbiota in the intestinal PolyFermS fermentation model inoculated with five independently immobilized human adult fecal microbiota.

View Article and Find Full Text PDF

The spoilage of vacuum-packed meat by complex (CEC), which is accompanied by or without production of copious amounts of gas, has been linked to the acetone-butyrate-ethanol fermentation, but the mechanism behind the variable gas production has not been fully elucidated. The reconstruction and comparison of intra- and interspecies metabolic pathways linked to meat spoilage at the genomic level can unravel the genetic basis for the variable phenotype. However, this is hindered by unavailability of CEC genomes, which in addition, has hampered the determination of genetic diversity and its drivers within CEC.

View Article and Find Full Text PDF

Parkinson's disease (PD) is associated with aberrant innate immune responses, including microglial activation and infiltration of peripheral myeloid cells into the central nervous system (CNS). Methods to investigate innate immune activation in PD are limited and have not yet elucidated key interactions between neuroinflammation and peripheral inflammation. Translocator protein 18 kDa (TSPO) PET is a widely evaluated imaging approach for studying activated microglia and peripheral myeloid lineage cells in vivo but has yet to be fully explored in PD.

View Article and Find Full Text PDF

Antimicrobial resistance in pathogenic bacteria is considered a major public health issue necessitating the discovery of alternative antimicrobial compounds. In this regard, targeted genome mining in bacteria occupying under-explored ecological niches has the potential to reveal such compounds, including bacteriocins. In this study, we determined the bacteriocin biosynthetic potential of the psychrophilic complex (CEC) through a combination of genome mining and phenotypic screening assays.

View Article and Find Full Text PDF

is a public health and food safety challenge due to its virulence and natural stress resistance phenotypes. The variable distribution of molecular subtypes with respect to food products and processing environments and among human and animal clinical listeriosis cases is observed. Sixty-two clinical and food-associated isolates were examined through phenome and genome analysis.

View Article and Find Full Text PDF

Shiga toxin-producing Escherichia coli (STEC) belonging to the serogroup O91 are among the most common non-O157 STEC serogroups associated with human illness in Europe. This study aimed to analyse the virulence factors, antimicrobial resistance genes and phylogenetic relatedness among 48 clinical STEC O91 isolates collected during 2003-2019 in Switzerland. The isolates were subjected to whole genome sequencing using short-read sequencing technologies and a subset of isolates additionally to long-read sequencing.

View Article and Find Full Text PDF

Background: Auto-aggregation is a desired property for probiotic strains because it is suggested to promote colonization of the human intestine, to prevent pathogen infections and to modulate the colonic mucosa. We recently reported the generation of adapted mutants of Lactiplantibacillus plantarum NZ3400, a derivative of the model strain WCFS1, for colonization under adult colonic conditions of PolyFermS continuous intestinal fermentation models. Here we describe and characterize the emerge of an auto-aggregating phenotype in L.

View Article and Find Full Text PDF