Prevalence of sea, seb, tsst, and mecA Genes in Staphylococcus aureus Isolated from Shrimps Sold in Seafood Retailers in Tehran, Iran

Prevalence, virulence factors, and antibiotic resistance of Staphylococcus aureus in seafood products

INTRODUCTION

Seafood contamination by bacteria is a pervasive issue, contributing to foodborne illnesses. This study investigates the prevalence, virulence factors, and antibiotic resistance in Staphylococcus aureus (S. aureus) isolated from various seafood products.

METHODS

A total of 460 samples, including fresh, smoked, salted, and dried fish, as well as oysters, crab, lobster, and shrimp, were collected in Shahrekord, Iran. S. aureus isolation followed ISO standards, with confirmation via PCR for 16S rRNA and nuc genes. Antibiotic susceptibility was determined via Kirby-Bauer disc diffusion, while PCR detected enterotoxin and antibiotic resistance genes.

FINDINGS

S. aureus was prevalent in all seafood types, with 27.83% positivity. Methicillin-resistant S. aureus (MRSA) was found in most samples, except oysters and crabs. Virulence genes were common, with Sea, Seb, Sed, Sec, and See being the most prevalent. High resistance to penicillin G and ampicillin (70%- 100%) was observed. Resistance varied for other antibiotics, with linezolid showing 100% susceptibility. The mecA gene was present in over 50% of isolates, with blaZ being the most detected resistance gene.

CONCLUSION

The study underscores the need for Good Hygiene Practices (GHP) in seafood processing to mitigate S. aureus transmission. While specific comparisons between sample types were limited, the findings emphasize the prevalence of virulence factors and antibiotic resistance in seafood-associated S. aureus, highlighting the importance of vigilant food safety measures.

Silent Carriers: The Hidden Threat of Antibiotic-Resistant Staphylococcus aureus in Retail Seafood Across Poland's Tri-City Area

Background/objectives: Antibiotic-resistant Staphylococcus aureus poses a significant risk to food safety and public health, particularly through the consumption of contaminated seafood. This study aimed to assess the presence and antibiotic resistance of S. aureus in seafood sold in the Tri-City area of Poland, addressing a knowledge gap regarding the region. Methods: Seafood samples (n = 89) were categorized according to their origin: domestic-Poland (PL), European countries (ECs), and Asian countries (ACs). S. aureus was isolated using ISO 6888-1 methods, and antimicrobial susceptibility testing was conducted against three antibiotics: erythromycin, clindamycin, and gentamicin, following CLSI guidelines. Results: Of the 89 samples, 68.5% were contaminated with S. aureus. The highest resistance rates were found for erythromycin (30.5%), with gentamicin showing the lowest resistance (8.3%).No significant correlation (p > 0.05) was found between resistance patterns and fish origin or processing level. Conclusions: The results of this study highlight the widespread occurrence of Staphylococcus aureus in fish sold in the Tri-City area, with a notable prevalence of antibiotic-resistant strains.

Review of Detection Limits for Various Techniques for Bacterial Detection in Food Samples

Foodborne illnesses can be infectious and dangerous, and most of them are caused by bacteria. Some common food-related bacteria species exist widely in nature and pose a serious threat to both humans and animals; they can cause poisoning, diseases, disabilities and even death. Rapid, reliable and cost-effective methods for bacterial detection are of paramount importance in food safety and environmental monitoring. Polymerase chain reaction (PCR), lateral flow immunochromatographic assay (LFIA) and electrochemical methods have been widely used in food safety and environmental monitoring. In this paper, the recent developments (2013-2023) covering PCR, LFIA and electrochemical methods for various bacterial species (Salmonella, Listeria, Campylobacter, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)), considering different food sample types, analytical performances and the reported limit of detection (LOD), are discussed. It was found that the bacteria species and food sample type contributed significantly to the analytical performance and LOD. Detection via LFIA has a higher average LOD (24 CFU/mL) than detection via electrochemical methods (12 CFU/mL) and PCR (6 CFU/mL). Salmonella and E. coli in the Pseudomonadota domain usually have low LODs. LODs are usually lower for detection in fish and eggs. Gold and iron nanoparticles were the most studied in the reported articles for LFIA, and average LODs were 26 CFU/mL and 12 CFU/mL, respectively. The electrochemical method revealed that the average LOD was highest for cyclic voltammetry (CV) at 18 CFU/mL, followed by electrochemical impedance spectroscopy (EIS) at 12 CFU/mL and differential pulse voltammetry (DPV) at 8 CFU/mL. LOD usually decreases when the sample number increases until it remains unchanged. Exponential relations (R2 > 0.95) between LODs of Listeria in milk via LFIA and via the electrochemical method with sample numbers have been obtained. Finally, the review discusses challenges and future perspectives (including the role of nanomaterials/advanced materials) to improve analytical performance for bacterial detection.

[Methicillin-resistant Staphylococcus aureus in the Americas: systematic review and metanalysis of prevalence in food-producing animalsStaphylococcus aureus resistente a la meticilina en la Región de las Américas: revisión sistemática y metanálisis de la prevalencia en la actividad agropecuaria]

OBJECTIVE

To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in animals used to produce foods in the Americas.

METHOD

A systematic literature review was performed in the following databases: Scopus, Web of Science, MEDLINE, EMBASE, and Virtual Health Library. Articles published in the past 10 years, without language limits, were selected. The outcome of interest was the prevalence of MRSA in food-producing animals. Prevalence rates were meta-analyzed in grouped random effects models using the DerSimonian and Laird method. The geographic distribution of MRSA and the time trend of resistance were also analyzed.

RESULTS

Of 19 studies included, 11 were performed in the United States and 11 analyzed pig samples. Five studies were performed in South America. The samples analyzed in the studies were collected in farming, processing, and retail sites. MRSA prevalence in the Americas was 7.6% (95%CI: 5.6-9.5%), and was higher in pigs [12.6% (95%CI: 7.0-18.2%)] followed by bovine cattle [2.4% (95%CI: 1.2-3.7%)] and poultry [1.8% (95CI%: 0.3-3.4%)]. MRSA prevalence was higher in pigs in North America and bovine cattle in Latin America. There was no significant variation in MRSH prevalence along the 10-year period analyzed.

CONCLUSIONS

MRSA prevalence in food-producing animals in the Americas was higher in pigs, without significant changes across time.