Human noroviruses are the leading cause of non-bacterial shellfish-associated gastroenteritis. In 2022, a multi-jurisdictional norovirus outbreak associated with contaminated oysters occurred that involved hundreds of illnesses. Here, we conducted genetic analysis on 30 clinical samples associated with this oyster outbreak. We first determined the capsid genotypes by Sanger sequencing and viral titers by droplet-digital reverse transcription PCR. Multiple genotypes were identified in this outbreak, which could indicate contamination with wastewaters. The majority of samples belonged to GII.3[P12], followed by GII.2[P16], GII.17[P17], and GII.4 Sydney[P16]. We next proceeded with whole-genome sequencing and obtained full genomes for 19 samples. Phylogenetic analysis revealed that some of the isolates showed high similarity with the sequences isolated from the United States related to the same outbreak. We also analyzed amino acid variations in the sequenced genomes and found that overall the GII.3[P12] isolates have lower variations compared to other genotypes. IMPORTANCE: Norovirus outbreaks associated with contaminated shellfish occur frequently. Whole-genome sequencing (WGS) could play a critical role in understanding and controlling norovirus outbreaks as it allows for source attribution, tracking transmission pathways, and detecting recurrent or linked outbreaks. Here, we described how the data obtained by WGS were employed for understanding transmission patterns and norovirus epidemiology.

Staphylococcus aureushas been involved in transfusion-transmitted fatalities associated with platelet concentrates (PCs) due to its heightened pathogenicity enhanced by genome-encoded virulence and antibiotic resistance genes. This may be facilitated by mobile genetic elements (MGEs) that can cause rearrangements. Several factors contribute toS. aureusvirulence, including the type VII secretion system (T7SS), composed of six core genes conserved acrossS. aureusstrains. In this study, we conducted comparative genome analyses of fiveS. aureusisolates from PCs (CI/BAC/25/13 /W, PS/BAC/169/17 /W and PS/BAC/317/16 /W were detected during PCs screening with the BACT/ALERT automated culture system, and ATR-20003 and CBS2016-05 were missed during screening and caused septic transfusion reactions). Multiple alignments of the genomes revealed evidence of rearrangements involving phage Sa3int in PS/BAC/169/17 /W and PS/BAC/317/16 /W. While the former had undergone translocation of its immune evasion cluster (IEC), the latter had lost part of the phage, leaving behind the IEC. This observation highlightsS. aureusgenome plasticity. Unexpectedly, strain CBS2016-05 was found to encode a pseudo-type VII secretion system (T7SS) that had lost five of the conserved core genes (esxA,esaA, essA, esaBandessB) and contained a 5′ truncatedessC. Since these genes are essential for the function of the T7SS protein transport machinery, which plays a key role inS. aureusvirulence, CBS2016-05 probably compensates by recruiting other export mechanisms and/or alternative virulence factors, such as neu-tralizing immunity proteins. This study unravels genome rearrangements inS. aureusisolated from PCs and reports the firstS. aureusisolate lacking conserved T7SS core genes.

Food-borne diseases affect nearly 10% of the global population annually, with Salmonella being a major cause, particularly impacting children, the elderly, and populations in low- and middle-income countries. This study aimed to assess the prevalence, serotype distribution, antibiotic resistance profiles, and genetic determinants of resistance and virulence of Salmonella enterica in humans and poultry in the Nanoro health district. A community-based cross-sectional study involving humans and poultry was conducted in the Nanoro health district. Fresh stool samples (human and poultry cloacal/cecal) were collected, transported under sterile conditions, and processed within two hours using standard bacteriological methods. Phenotypic antibiotic resistance was determined by the Kirby–Bauer disk diffusion method, and whole-genome sequencing (Illumina) identified serotypes, resistance genes, and virulence factors. Logistic regression analyzed associations between Salmonella carriage and host or environmental factors. Salmonella enterica carriage was detected in 8.7% of humans and 7.2% of poultry. Human isolates showed 24% resistance to cephalosporins, while poultry isolates showed 36.8% resistance. Resistance genes, including fosA7, qnrB19, and a cryptic aminoglycoside resistance gene, and virulence genes encoding T3SS-1 and T3SS-2, were detected in both hosts. Logistic regression indicated that residence in Sitaon and Zimidin was associated with ~70% lower odds of carriage (aOR = 0.3), while individuals aged 11–20 and 51–60 years had 2.8-fold higher odds. Carriage was also 60% higher during the rainy season. These findings suggest possible cross-transmission of Salmonella between humans and poultry and the circulation of resistant, potentially virulent strains in the community. Seasonal and age-related variations highlight environmental and behavioral influences on asymptomatic carriage. Integrated One Health surveillance and targeted hygiene interventions are essential to reduce Salmonella transmission and antimicrobial resistance in rural settings.

Staphylococcus epidermidis is one of the predominant bacterial contaminants in platelet concentrates (PCs), a blood component used to treat bleeding disorders. PCs are a unique niche that triggers biofilm formation, the main pathomechanism of S. epidermidis infections. We performed whole genome sequencing of four S. epidermidis strains isolated from skin of healthy human volunteers (AZ22 and AZ39) and contaminated PCs (ST10002 and ST11003) to unravel phylogenetic relationships and decipher virulence mechanisms compared to 24 complete S. epidermidis genomes in GenBank. AZ39 and ST11003 formed a separate unique lineage with strains 14.1 .R1 and SE95, while AZ22 formed a cluster with 1457 and ST10002 closely grouped with FDAAGOS_161. The four isolates were assigned to sequence types ST1175, ST1174, ST73 and ST16, respectively. All four genomes exhibited biofilm-associated genes ebh, ebp, sdrG, sdrH and atl. Additionally, AZ22 had sdrF and aap, whereas ST10002 had aap and icaABCDR. Notably, AZ39 possesses truncated ebh and sdrG and harbours a toxin-encoding gene. All isolates carry multiple antibiotic resistance genes conferring resistance to fosfomycin (fosB), β-lactams (blaZ) and fluoroquinolones (norA). This study reveales a unique lineage for S. epidermidis and provides insight into the genetic basis of virulence and antibiotic resistance in transfusion-associated S. epidermidis strains.

Cutibacterium acnes is a bacterial skin commensal that is often isolated during routine testing of blood products like platelet concentrates (PCs). Due to the slow-growing nature of this bacterium in culture media, C. acnes contaminated PCs are often transfused into vulnerable patients before retrieval of these units can be initiated. This study aimed at obtaining the whole-genome sequence of six C. acnes isolates derived from contaminated PCs, comparing and assessing their genetic backgrounds. Furthermore, the whole genomes of the PC isolates were compared to clinical isolates obtained from different sites and types of infection. The results indicate that these PC isolates assessed belong to four phylotypes, namely IA, IB, II and III. Whole-genome comparisons identified differences in the virulence profiles of the isolates and provide a foundation for future studies aimed at evaluating the risk to transfusion patients by determining whether the expression of virulence factors is impacted in the PC storage environment.

Foodborne botulism is a severe neuroparalytic disease caused by ingestion of foods containing botulinum neurotoxins, produced by Clostridium botulinum. In 2024, a 74-year-old woman from Newfoundland and Labrador with complete bilateral flaccid paralysis and respiratory distress was hospitalized and required intubation. From the broader differential diagnosis list, botulism was favoured prior to laboratory confirmation. Serum and feces samples initially tested negative for botulinum neurotoxins by mouse bioassay, yet viable C. botulinum type A was recovered from the feces. Food history investigation included some diced garlic in a repurposed coffee container that tested negative for botulinum neurotoxins by mouse bioassay, but viable C. botulinum type A was recovered from the sample. Both the fecal and garlic enrichment cultures were positive for bont/A and bont/B genes by real-time PCR. Whole genome sequencing revealed that both fecal and garlic isolates were highly similar with conserved gene synteny, including an intact bont/A1 gene and a disrupted (silent) bont/B5 gene encoded on the chromosome. This single-case foodborne botulism outbreak from Newfoundland and Labrador in 2024 was caused by C. botulinum type A1(B5) in diced garlic.