Methicillin-resistant Staphylococcus aureus (MRSA) is a major challenge for food safety and public health. This study aimed to investigate the potential role of oysters sold in Egypt as a source for Staphylococcus aureus (S. aureus), MRSA, and multidrug-resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA). It also examined the occurrence of tsst-1 virulence gene and assessed the associated zoonotic risks. Thirty-three pooled fresh oyster samples were acquired from different retail fish markets in Egypt. S. aureus was identified by conventional culture-based and molecular methods. Antimicrobial resistance was performed by the disk-diffusion method, and the multiple antibiotic resistance index (MARI) was calculated. Antimicrobial resistance (mecA and mecC) and virulence (tsst-1) genes were screened using polymerase chain reaction. The clustering of virulent MDR-MRSA isolates was performed using R with the pheatmap package. The prevalence of S. aureus was 39.4% (13 /33), and 77% of them (10/13) were classified as MDR with MARI values greater than 0.2. Notably, 46.2% (6 /13) of isolates were identified as MRSA and all MRSA isolates displayed MDR. Of the MDR-MRSA isolates, 66.7% (4 /6) possessed the mecA gene, while 16.7% (1 /6) tested positive for the mecC gene. Additionally, the tsst-1 gene was identified in one isolate (16.7%). Interestingly, two MDR-MRSA isolates exhibited a clustered pattern. The study sheds light on the emergence of virulent MDR-MRSA isolates in Egyptian oysters. It highlights oysters as a potential source for spreading these isolates within aquatic ecosystems, posing a threat to food safety and public health.

Seafood plays a vital role in human diets worldwide, serving as an important source of high-quality protein, omega-3 fatty acids, and essential vitamins and minerals that promote health and prevent various chronic conditions. The health benefits of seafood consumption are well documented, including a reduced risk of cardiovascular diseases, improved cognitive function, and anti-inflammatory effects. However, the safety of seafood is compromised by multiple hazards that can pose significant health risks. Pathogenic microorganisms, including bacteria, viruses, and parasites, in addition to microbial metabolites, are prominent causes of the foodborne diseases linked to seafood consumption, necessitating reliable detection and monitoring systems. Molecular biology and digital techniques have emerged as essential tools for the rapid and accurate identification of these foodborne pathogens, enhancing seafood safety protocols. Additionally, the presence of chemical contaminants such as heavy metals (e.g., mercury and lead), microplastics, and per- and polyfluoroalkyl substances (PFASs) in seafood is of increasing concern due to their potential to accumulate in the food chain and adversely affect human health. The biogenic amines formed during the microbial degradation of the proteins and allergens present in certain seafood species also contribute to food safety challenges. This review aims to address the nutritional value and health-promoting effects of seafood while exploring the multifaceted risks associated with microbial contamination, chemical pollutants, and naturally occurring substances. Emphasis is placed on enhanced surveillance, seafood traceability, sustainable aquaculture practices, and regulatory harmonization as effective strategies for controlling the risks associated with seafood consumption and thereby contributing to a safer seafood supply chain.

Since its discovery about 50 years ago, Vibrio parahaemolyticus has been implicated as a major cause of foodborne illness around the globe. V. parahaemolyticus is a natural inhabitant of marine waters. Human infections are most commonly associated with the consumption of raw, undercooked or contaminated shellfish. A few individual V. parahaemolyticus virulence factors, including the thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH), have been investigated in depth, yet a comprehensive understanding of this organism's ability to cause disease remains unclear. Since 1996, serotype O3:K6 strains have been associated with an increased incidence of gastroenteritis in India and in Southeast Asia, and with large-scale foodborne outbreaks in the United States (US). In light of the emerging status of pathogenic V. parahaemolyticus, the US Food and Drug Administration conducted a microbial risk assessment to characterize the risk of contracting V. parahaemolyticus infections from consuming raw oysters. This review summarizes epidemiological findings, discusses recognized and putative V. parahaemolyticus virulence factors and pathogenicity mechanisms, and describes strategies for preventing V. parahaemolyticus infections.

Human bocavirus (HBoV) is an emerging pathogen causing gastroenteritis/respiratory tract infection. Shellfish has been implicated in foodborne HBoV dissemination. The present investigation aimed at synthesising shellfish-associated HBoV data. Shellfish-HBoV data were mined from public repositories using topic-specific algorithm. A total of 30 data sources was identified of which 5 were synthesised. The average HBoV positivity and sample-size was 12 ± 9.2 and 134.2 ± 113.6, respectively. HBoV was studied in mollusc with 3.7-83.3% crude prevalence. The pooled HBoV prevalence in shellfish was 9.2% (7.2-11.8; 5 studies) and 12.9% (1.8-53.9; 5 studies) in common-effects and random-effects model respectively, with 0.12-94.89% prediction interval (PI). Sensitivity analysis yielded 8.7% (6.7-11.2; PI = 1.99-29.48%) prevalence. HBoV1 and HBoV2 pooled prevalence in shellfish was 7.91% (1.61-31.09; 3 studies) and 12.52% (0.01-99.60; 3 studies), respectively. HBoV3 prevalence was reported in one single study as 6.96% (4.41-10.35). In conclusion, the present study revealed high HBoV prevalence in shellfish, signifying the need to characterise HBoV and subtypes circulating in non-mollusc shellfish. Furthermore, there is an urgent need to mitigate the food safety risk that may result from HBoV contaminated shellfish since shellfish-borne HBoV is not routinely assessed and might be underestimated at present.

Vibrio vulnificus infection after raw oyster ingestion in a patient with liver disease and acquired immune deficiency syndrome-related complex. Sepsis, peritonitis, and gastroenteritis developed in a 45-yr-old homosexual man 1 day after ingestion of raw oysters. The patient had chronic active hepatitis and cirrhosis with hepatitis B virus and delta-infection. He also had persistent generalized lymphadenopathy associated with HTLV-III antibody positivity. Vibrio vulnificus was isolated from the patient's blood and peritoneal fluid as well as from the same batch of oysters at the restaurant where the patient had visited. To our knowledge, this is the first report relating direct microbiologic and clinical evidence that the infection is acquired through the gastrointestinal tract by consuming raw seafood containing the pathogen. This is also the first reported case of peritonitis associated with sepsis and gastroenteritis from this organism. Patients with liver disease and other immunocompromised states should be warned about such life-threatening infections and complications associated with the consumption of raw oysters or other undercooked seafoods.

Vibrio parahaemolyticus (VP) is a bacterial pathogen found in brackish and marine water that infects many marine organisms, such as oysters and shrimp. Consumption of raw or undercooked seafood contaminated with V. parahaemolyticus is a primary cause of seafood-borne gastroenteritis in humans. Due to increasing ocean temperatures, V. parahaemolyticus contamination of oyster beds in the United States has spread up the east and west coasts to the northern-most states. Promising new research is exploring the isolation of bacteriophages against V. parahaemolyticus with a long-term goal to possibly

The Prevalence of Enteric Viruses in Bivalve Molluscs in a Farming Area in Liguria, Northwest Italy Bivalve molluscs are filter-feeding organisms, capable of concentrating pathogenic microorganisms from the surrounding environment, thus contributing to the spread of viral pathogens, which they can transmit to humans, especially if eaten raw or undercooked. Although norovirus (NoV) and the hepatitis A virus (HAV) are considered the most common causes of foodborne infections, in recent years, other viruses with a zoonotic potential have been identified in shellfish, such as the hepatitis E virus (HEV), astrovirus (AsV), and aichi virus (AiV). The aim of the study was to investigate the presence of classical and emerging pathogenic enteric viruses in oysters (<i>Crassostrea gigas</i>) and mussels (<i>Mytilus galloprovincialis</i>) from a mollusc farming area in the northwest of Italy, between April 2022 and March 2023. In the period considered, a total of 168 samples (84 oysters and 84 mussels) were analysed. The prevalence of NoV was highest, with 32.7% (55/168) positive samples, followed by 18.4% (31/168) for AsV and 19.6% (33/168) for AiV.

<i>Plesiomonas shigelloides</i>, an aquatic Gram-negative bacillus often associated with self-limiting gastroenteritis, has been reported worldwide. However, to date, no reviews have specifically investigated <i>P. shigelloides</i> bacteremia, which is rare and potentially fatal. This scoping review aimed to examine the existing literature to identify the epidemiology, clinical characteristics, antimicrobial susceptibility, and outcomes of <i>P. shigelloides</i> bacteremia. A PRISMA-ScR-guided search of PubMed, Scopus, Web of Science, and Embase identified 22 published cases, all reported as single-patient case reports. Cases were globally distributed, with the majority reported from the Americas and Europe. The median patient age was 46 years. The case fatality rate was 27.3% (<i>n</i> = 6/22). Most patients had identifiable host risk factors, particularly hematological disorders, neonatal status, or immunocompromised status, and environmental exposure such as raw seafood consumption or contact with freshwater. Clinical presentations were heterogeneous, commonly including fever and sepsis or septic shock. Microbiologically, <i>P. shigelloides</i> demonstrated consistent intrinsic resistance to ampicillin while retaining susceptibility to multiple antimicrobial classes. Poor outcomes were more closely associated with host factors and delayed presentation than with antimicrobial resistance. Early diagnosis, targeted therapy, and antimicrobial stewardship are essential for optimizing outcomes in this rare but severe infection.