Table 3.

ARGs and ARG families found in five or more of the communities

ARG description	No. of sites with ARG
Resistance-nodulation-cell division transporter system. Multidrug resistance efflux pump. Macrolide-specific efflux system	9
MacB is an ATP-binding cassette (ABC) transporter that exports macrolides with 14- or 15-membered lactones	8
dfrE is a chromosome-encoded dihydrofolate reductase found in Enterococcus faecalis	8
Efflux pump/potassium antiporter system. RosA: major facilitator superfamily transporter	7
Alanyl-tRNA synthetase conferring resistance to novobiocin in Escherichia coli	7
The enzymatic inactivation of rifampin by phosphorylation at the 21-OH position	6
Undecaprenyl pyrophosphate phosphatase, which consists in the sequestration of Undecaprenyl pyrophosphate	5
ARG family description	Number of sampled sites
Undecaprenyl pyrophosphate phosphatase, which consists in the sequestration of Undecaprenyl pyrophosphate	12
ABC efflux/transporter system	12
Efflux pump/potassium antiporter system. RosA: major facilitator superfamily transporter	9
dfrE is a chromosome-encoded dihydrofolate reductase found in Enterococcus faecalis	8
Aminocoumarin resistant alaS. Alanyl-tRNA synthetase conferring resistance to novobiocin in Escherichia coli	7
Resistance-nodulation-cell division transporter system. Multidrug resistance efflux pump	6
The enzymatic inactivation of rifampin by phosphorylation at the 21-OH position	6
Aminoglycoside acetyltransferase/nucleotidylyltransferase, which modifies aminoglycosides by acetylation/adenylylation	6
Major facilitator superfamily transporter, tetracycline efflux pump	5