A meta-analysis of the global prevalence of methicillin-resistant Staphylococcus aureus (MRSA) isolated from clinical and subclinical bovine mastitis

Aims: This meta-analysis aims to assess the point prevalence of methicillin-resistant Staphylococcus aureus (MRSA) isolated from bovine mastitis cases at the global level. Methods and Results: Several electronic databases were searched for relevant publications (PubMed, EMBASE, Web of Knowledge and Cochrane Library). Heterogeneity between studies was assessed using the Cochrane Q test and I2 test statistics based on the random-effect model. The potential sources of between-study heterogeneity were evaluated using subgroup analysis and meta-regression. Sensitivity and publication bias analyses were performed. Sixty-six studies with a total of 77,644 mastitis cases were eligible and included in the analysis. The overall pooled prevalence of MRSA was 4·30% (95% CI: 3·24–5·50) with a significant heterogeneity (I2 = 97·48%, p < 0·001). In the subgroup analysis by region, the highest prevalence was found in Asia (6·47%, 95% CI: 4·33–8·97), and the lowest prevalence was reported in Europe (1·18%, 95% CI: 0·18–2·83). The pooled prevalence was significantly higher in clinical mastitis and cases published during 2016–2020. Conclusions: The results of this study suggest that there is a lower prevalence of MRSA in bovine mastitis. However, its prevalence increased in the past 4 years. Therefore, continuous surveillance is urgently required for monitoring the dissemination of these clinically important bacteria. Significance of the Study: To our knowledge, this is the first meta-analysis to estimate the global prevalence of MRSA isolated from bovine mastitis cases.