Phage or plasmid strain tracking when used to identify strain sharing in twin infant pairs. Test results for previously published tools (MIDAS, StrainPhlAn and inStrain) were obtained from the literature 28 . Classification as the same strain of conspecific strains residing in twin infants by each of the tools was considered as a true-positive classification, while classification of strains as the same in unrelated infants was considered as a false-positive classification. The AUC is an estimator of the method performance, in terms of the ratio of true-positive rate and false-positive rate at different ANI (MIDAS, inStrain and StrainPhlAn) or APSS (SynTracker) values. n represents the total number of strain-pair comparisons performed by each tool.
