Human carriage of ESBL/pAmpC-producing Escherichia coli and Klebsiella pneumoniae in relation to the consumption of raw or undercooked vegetables, fruits, and fresh herbs

Abstract

We investigated to what extent the consumption of raw or undercooked vegetables, fruits, and fresh herbs influences carriage rates of ESBL/pAmpC-producing Escherichia coli and Klebsiella pneumoniae (ESBL-E/K) in the general population. We assessed long-term carriage and changes in ESBL-E/K prevalence over time, by comparing the results to findings in the same population 5 years earlier. Between July and December 2021, participants sent in two fecal samples and questionnaires, 3 months apart. Food frequency questionnaires were sent on a monthly basis. Fecal samples were cultured and screened for ESBL-E/K, and phenotypically positive isolates were sequenced. Multivariable logistic regression models were established to assess the association between the consumption of fresh produce and ESBL-E/K carriage. The ESBL-E/K prevalence was 7.6% [41/537; 95% confidence interval (CI): 5.7–10.2] in the first sampling round and 7.0% (34/489; 95% CI: 5.0–9.6) in the second. Multivariable models did not result in statistical significance for any of the selected fruit and vegetable types. Trends for increased carriage rates were observed for the consumption of raspberry and blueberry in the summer period. ESBL-E/K prevalence was comparable with the prevalence in the same cohort 5 years earlier (7.5%; 95% CI: 5.6–10.1%). In six persons (1.2%) a genetically highly homologous ESBL-E/K was found. In conclusion, the contribution of the consumption of raw fruits, vegetables, and herbs to ESBL-E/K carriage in humans in the Netherlands is probably low. Despite COVID-19 containment measures (e.g., travel restrictions, social distancing, and hygiene) the ESBL-E/K prevalence was similar to 5 years earlier. Furthermore, indications for long-term carriage were found. IMPORTANCE ESBL-producing bacteria are resistant against important classes of antibiotics, including penicillins and cephalosporines, which complicates treatment of infections. Food is one of the main routes of transmission for carriage of these bacteria in the general population. Although fruits, vegetables, and herbs are generally less frequently contaminated with ESBL-producing bacteria compared to meat, exposure might be higher since these products are often eaten raw or undercooked. This research showed that the contribution of the consumption of raw or undercooked fresh produce to ESBL-E/K carriage in the general Dutch population was low. No specific types of fruit or vegetables could be identified that gave a higher risk of carriage. In addition, we demonstrated the presence of genetically highly homologous ESBL-E/K in six persons after a period of 5 years, indicative for long-term carriage.