Relationship between livestock exposure and methicillin-resistant Staphylococcus aureus carriage in humans: A systematic review and dose–response meta-analysis

Abstract

Although previous studies have suggested an association between livestock exposure and the risk of methicillin-resistant Staphylococcus aureus (MRSA) carriage in humans, it remains unclear whether there is a dose-response relationship. The aim of this study was to evaluate the relationship between livestock exposure and MRSA carriage. Pooled risk estimates were calculated using fixed-effects or random-effects models based on homogeneity analysis. A dose-response meta-analysis based on linear and non-linear regression was performed to explore the frequency-risk relationship between livestock exposure and MRSA carriage. Subgroup analyses were conducted to explore sources of heterogeneity among eligible studies. A total of 25 studies were included in the meta-analysis. Livestock exposure was significantly associated with an increased risk of MRSA carriage [odds ratio (OR)=7.03, 95% confidence interval 4.29-11.52], and similar positive associations were observed for pig (OR=11.41), poultry (OR=6.20) and cattle (OR=5.66) exposure. Regarding studies on ordinal and continuous frequency of livestock exposure, a monotonically increasing frequency-risk relationship between livestock (or pig) exposure and MRSA carriage was consistently observed. This study found a monotonically increasing frequency-risk relationship between livestock exposure and MRSA carriage, which provides evidence for potential livestock-to-human transmission of MRSA.