Systematic Review of Wastewater Surveillance of Antimicrobial Resistance in Human Populations

We systematically reviewed studies using wastewater for AMR surveillance in human populations, to determine: (i) the strength of the evidence for a wastewater-human AMR association, and (ii) methodological approaches which optimised identifying such an association, and which could be recommended as standard. We used Lin’s concordance correlation coefficient (CCC) to quantify agreement between AMR prevalence in wastewater and human compartments, and logistic regression to identify study features (e.g. sampling methods) associated with high-agreement (defined as wastewater-human AMR prevalences within ±10%). Of 8,867 records and 232 full-text methods reviewed, 29 studies were included. AMR prevalence data was extractable from 20 studies conducting phenotypic-only (n=11), genotypic-only (n=1) or combined (n=8) AMR detection. Overall wastewater-human AMR concordance was reasonably high for both phenotypic (CCC=0.81 [95% CI 0.74-0.87]) and genotypic comparisons (CCC=0.88 (95% CI 0.85-0.91)) despite diverse species-phenotypes/genotypes and study design. Logistic regression was limited by inconsistent reporting of study features, and limited sample size; no significant relationships between study features and high wastewater-human AMR agreement were identified. Based on descriptive synthesis, composite/flow-proportional sampling of wastewater influent, longitudinal sampling >12 months, and time/location-matched comparisons generally had higher-agreement. Further research and clear and consistent reporting of study methods is required to confirm optimal practice.