Publications by authors named "Aldert L Zomer"

A diverse array of micro-organisms can be found on food, including those that are pathogenic or resistant to antimicrobial drugs. Metagenomics involves extracting and sequencing the DNA of all micro-organisms on a sample, and here, we used a combination of culture and culture-independent approaches to investigate the microbial ecology of food to assess the potential application of metagenomics for the microbial surveillance of food. We cultured common foodborne pathogens and other organisms including , spp.

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The recent growth of microbial sequence data allows comparisons at unprecedented scales, enabling the tracking of strains, mobile genetic elements, or genes. Querying a genome against a large reference database can easily yield thousands of matches that are tedious to interpret and pose computational challenges. We developed Graphite that uses a colored de Bruijn graph (cDBG) to paint query genomes, selecting the local best matches along the full query length.

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Bovine Genital Campylobacteriosis (BGC) is caused by Campylobacter fetus subsp. venerealis and is a notifiable disease to the WOAH (World Organisation for Animal Health). For an effective BGC control program, the reliable differentiation of Campylobacter fetus subsp.

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Unlabelled: In the global efforts to combat antimicrobial resistance and reduce antimicrobial use in pig production, there is a continuous search for methods to prevent and/or treat infections. Within this scope, we explored the relationship between the developing piglet nasal microbiome and (zoonotic) bacterial pathogens from birth until 10 weeks of life. The nasal microbiome of 54 pigs was longitudinally studied over 16 timepoints on 9 farms in 3 European countries (Germany, Ireland, and the Netherlands) using amplicon sequencing targeting the V3-V4 16S rRNA region as well as the gene for its staphylococcal discrimination power.

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Antimicrobial resistance (AMR) is an emerging worldwide problem and a health threat for humans and animals. Antimicrobial usage in human and animal medicine or in agriculture results in selection for AMR. The selective concentration of antimicrobial compounds can be lower than the minimum inhibitory concentration and differs between environments, which can be a reason for bacterial resistance.

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Most isolates carry the fucose utilization cluster () that supports the metabolism of l-fucose and d-arabinose. In this study we quantified l-fucose and d-arabinose metabolism and metabolite production, and the impact on Caco-2 cell interaction and binding to fibronectin, using NCTC11168 and the closely related human isolate strain 286. When cultured with l-fucose and d-arabinose, both isolates showed increased survival and production of acetate, pyruvate and succinate, and the respective signature metabolites lactate and glycolic acid, in line with an overall upregulation of l-fucose cluster proteins.

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In 2020 and 2022, nine cases of surgical site infections with a methicillin-resistant (MRSA) were diagnosed in horses in an equine referral clinic. Sixteen isolates (horses, =9; environment, =3; and staff members, =4) were analysed retrospectively using Nanopore whole-genome sequencing to investigate the relatedness of two suspected MRSA outbreaks (2020 and 2022). The MRSA isolates belonged to ST398 and ST612.

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Campylobacter was considered asaccharolytic, but is now known to carry saccharide metabolization pathways for L-fucose and d-glucose. We hypothesized that these clusters are beneficial for Campylobacter niche adaptation and may help establish human infection. We investigated the distribution of d-glucose and L-fucose clusters among ∼9600 C.

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Objectives: Antimicrobials can select for antimicrobial-resistant bacteria. After treatment the active compound is excreted through urine and faeces. As some antimicrobials are chemically stable, recirculation of subinhibitory concentrations of antimicrobials may occur due to coprophagic behaviour of animals such as chickens.

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Animal rehabilitation centres provide a unique opportunity to study the microbiome of wild animals because subjects will be handled for their treatment and can therefore be sampled longitudinally. However, rehabilitation may have unintended consequences on the animals' microbiome because of a less varied and suboptimal diet, possible medical treatment and exposure to a different environment and human handlers. Our study describes the gut microbiome of two large seal cohorts, 50 pups (0-30 days old at arrival) and 23 weaners (more than 60 days old at arrival) of stranded harbour seals admitted for rehabilitation at the Sealcentre Pieterburen in the Netherlands, and the effect of rehabilitation on it.

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Three strains from the nasal microbiota of healthy pigs were identified as candidates for reducing MRSA in pigs. The safety of nasal administration of a cocktail of these strains was examined in new-born piglets. Six days pre-farrowing, twelve sows were assigned to the placebo or cocktail group ( = 6/group).

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The gut microbiome of humans and animals acts as a reservoir of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC). Dogs are known for having a high prevalence of ESBL-EC in their gut microbiota, although their ESBL-EC carrier status often shifts over time. We hypothesized that the gut microbiome composition of dogs is implicated in ESBL-EC colonization status.

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is an important food-borne human pathogen and presents immunogenic surface polysaccharides, which can be used to distinguish problematic and disease-causing lineages. is divided in 16 O-serotypes (O-antigen) and 71 K-serotypes (K-antigen). Agglutination tests are still the gold standard for serotyping, but many isolates are not typable by agglutination.

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is a pathogen, which is primarily associated with fertility problems in sheep and cattle. In humans, it can cause severe infections that require antimicrobial treatment. However, knowledge on the development of antimicrobial resistance in is limited.

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Background: Hospitalisation and antimicrobial treatment are common in horses and significantly impact the intestinal microbiota. Antimicrobial treatment might also increase levels of resistant bacteria in faeces, which could spread to other ecological compartments, such as the environment, other animals and humans. In this study, we aimed to characterise the short- and long-term effects of transportation, hospitalisation and trimethoprim-sulfadiazine (TMS) administration on the faecal microbiota and resistome of healthy equids.

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Food products carry bacteria unless specifically sterilised. These bacteria can be pathogenic, commensal or associated with food spoilage, and may also be resistant to antimicrobials. Current methods for detecting bacteria on food rely on culturing for specific bacteria, a time-consuming process, or 16S rRNA metabarcoding that can identify different taxa but not their genetic content.

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Selection and spread of Extended Spectrum Beta-Lactamase (ESBL) -producing Enterobacteriaceae within animal production systems and potential spillover to humans is a major concern. Intramammary treatment of dairy cows with first-generation cephalosporins is a common practice and potentially selects for ESBL-producing Enterobacteriaceae, although it is unknown whether this really occurs in the bovine fecal environment. We aimed to study the potential effects of intramammary application of cephapirin (CP) and cefalonium (CL) to select for ESBL-producing Escherichia coli in the intestinal content of treated dairy cows and in manure slurry, using in vitro competition experiments with ESBL and non-ESBL E.

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can be transmitted between dogs and their owners and can cause opportunistic infections in humans. Whole genome sequencing was applied to identify the relatedness between isolates from human infections and isolates from dogs in the same households. Genome SNP diversity and distribution of plasmids and antimicrobial resistance genes identified related and unrelated isolates in both households.

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Background: Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading cause of bacteremia worldwide, with older populations having increased risk of invasive bacterial disease. Increasing resistance to first-line antibiotics and emergence of multidrug-resistant (MDR) strains represent major treatment challenges. ExPEC O serotypes are key targets for potential multivalent conjugate vaccine development.

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and were previously considered asaccharolytic, but are now known to possess specific saccharide metabolization pathways, including L-fucose. To investigate the influence of the L-fucose utilization cluster on growth, survival and metabolism, we performed comparative genotyping and phenotyping of the reference isolate NCTC11168 (human isolate), Ca1352 (chicken meat isolate), Ca2426 (sheep manure isolate), and Ca0121 (pig manure isolate), that all possess the L-fucose utilization cluster. All isolates showed enhanced survival and prolonged spiral cell morphology in aging cultures up to day seven in L-fucose-enriched MEMα medium (MEMαF) compared to MEMα.

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Article Synopsis
  • A nosocomial pathogen often leads to healthcare-related infections, with multidrug-resistant (MDR) strains posing significant public health risks due to their environmental survival.
  • Two separate MDR outbreaks occurred in a Netherlands animal ICU in 2012 and 2014, prompting a study that analyzed dog and environmental isolates through whole-genome sequencing (WGS).
  • Findings revealed that despite all clinical isolates showing identical resistance patterns and being linked to the same sequence type (ST2), they were genetically distinct, indicating different origins and emphasizing the need for advanced genomic analysis to mitigate MDR infections in veterinary settings.
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Antimicrobial-resistance (AMR) genes in bacteria are often carried on plasmids and these plasmids can transfer AMR genes between bacteria. For molecular epidemiology purposes and risk assessment, it is important to know whether the genes are located on highly transferable plasmids or in the more stable chromosomes. However, draft whole-genome sequences are fragmented, making it difficult to discriminate plasmid and chromosomal contigs.

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is an important pathogen in dogs that occasionally causes infections in humans as an opportunistic pathogen of elderly and immunocompromised people. This study compared the genomic relatedness and antimicrobial resistance genes using genome-wide association study (GWAS) to examine host association of canine and human isolates. Canine ( = 25) and human ( = 32) methicillin-susceptible (MSSP) isolates showed a high level of genetic diversity with an overrepresentation of clonal complex CC241 in human isolates.

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Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen and often colonizes pigs. To lower the risk of MRSA transmission to humans, a reduction of MRSA prevalence and/or load in pig farms is needed. The nasal microbiome contains commensal species that may protect against MRSA colonization and may be used to develop competitive exclusion strategies.

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