Table 1 Candidate indicator assays for major gene classes in UWTP effluents.

Assays that yielded the highest amplification in the largest number of samples are reported on the left. Assays with the most representative outcome in terms of correlation with the per-class mean are reported on the right (rho: Spearman’s rank correlation coefficient). Primer pairs corresponding to the assay are listed in table S2.

Gene class
(no. of assays)
Genes dominating the classMost representative genes
GeneAssay ID% of samplesGeneAssay IDRho
Aminoglycoside (24)aadAAY16762.90.96
Amphenicol (14)cmxAAY12927.1cmlAAY1270.74
β-Lactam (61)blaOXAAY4434.50.76
MDR (40)qacEdelta1AY15992.10.97
MLSB (30)ermFAY2368.60.81
Quinolone (3)qnrSrtF11AY6100.01.00
Sulfonamide (9)sul1AY36373.00.82
Tetracycline (34)tetQAY18559.6tetXAY1960.73
Insertion
sequence (9)
ISPpsAY36986.50.98
Integrase (7)intI1AY33680.90.96
Transposase (10)tnpAAY20279.30.86