Prevalence, antibiotic resistance, and enterotoxin genes of Staphylococcus aureus isolated from milk and dairy products worldwide: A systematic review and meta-analysis

Staphylococcal food poisoning is one of the common causes of food diseases, and the risk factor is staphylococcal enterotoxin. Milk and dairy products are often contaminated by antibiotic resistance and enterotoxins Staphylococcus aureus (S. aureus), which has become a critically important global public health concern. This study reviewed research studies on S. aureus in milk and dairy products worldwide published before October 2021 in PubMed, EMBASE, Scopus, and Web of Science to estimate the prevalence, antimicrobial resistance, and enterotoxin genes using a meta-analysis method. In addition, subgroup analysis, sensitivity analysis and regression analysis were conducted to explore the sources of the heterogeneity. The results showed that 140 eligible studies were published between 1992 and 2021. In raw milk, the prevalence (33.36%, 95% CI: 27.18-39.84%) was higher than that in dairy products and pasteurized milk, while it decreased over the publication period (P = 0.02). Subgroup analysis showed that the prevalence of S. aureus isolated from dairy plants was higher than that isolated from farms and retail markets. Among the 12 antibiotics, the resistance rates of penicillin (73.85%, 95% CI: 67.05-80.17%) and ampicillin (59.63%, 95% CI: 47.31-71.41%) were the highest, and the antibiotic resistance of ampicillin, gentamicin and chloramphenicol increased over time (P < 0.05). The pooled rate of classical staphylococcus enterotoxins was 39.31% (95% CI: 25.99-53.44%), and the highest rates were found for sec and sea genes. In conclusion, the hygiene and safety of raw milk can be guaranteed by improving the health of milking animals, elevating milking hygiene and using pasteurization. Developing β-lactamase inhibitors and strengthening antibiotic resistance surveillance systems may alleviate antibiotic resistance issues. Transportation and storage according to regulation and standards may reduce the contamination of staphylococcus enterotoxins in raw milk.