Gut colonisation with extended-spectrum beta-lactamase producing Enterobacteriaceae in vegetarians: A systematic review and meta-analysis

Individuals colonised with extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBL-PE) are at high risk of ESBL-PE infection. Eating a vegetarian diet may influence ESBL-PE gut colonisation due to reduced exposure to contaminated meat. We systematically reviewed studies exploring whether vegetarian diet is associated with ESBL-PE gut colonisation. Combining terms for ESBL-PE and vegetarian diet we searched Embase, Medline, CINAHL, and Web of Science for studies from January 2000 to July 2023 to identify studies that compare ESBL-PE gut colonisation in vegetarians and non-vegetarians. We estimated a pooled odds ratio (OR) using a random-effects model. We also did subgroup analyses of studies conducted in the general population and in recent travellers and assessed study heterogeneity. We identified 2,471 papers, 14 were included in our meta-analysis (11 recruited from the general population; 3 recruited recent travellers). Overall, included studies provided information on ESBL-PE colonisation for 1,396 vegetarians and 11,411 non-vegetarians. There was moderate heterogeneity in study outcomes overall (I2 = 52.4 %), low heterogeneity among studies in the general population (I2 = 14.7 %), and high heterogeneity among studies in recent travellers (I2 = 81.7 %). Vegetarians had similar odds of ESBL-PE gut colonisation compared with non-vegetarians (pooled OR 1.25, 95 %CI 0.84-1.87). This finding was consistent in studies of the general population (pooled OR 1.30, 95 %CI 0.95-1.79) and in recent travellers (pooled OR 1.27, 95 %CI 0.34-4.73). Vegetarians and non-vegetarians have a similar risk of ESBL-PE gut colonisation. Further studies using a precise definition of vegetarianism which are large enough to adjust for known and potential confounders could add greater certainty to this conclusion.