A: ARG distribution and relative abundance by corresponding
antibiotic categories. ARGs were annotated via MetaStorm using CARD
version 1.2.1. ARG categories were assigned in-house (Supplemental Data 1). Genes corresponding to
two or more categories were labeled as “multidrug”.
ARG abundances were normalized via MetaStorm to 16S rRNA gene abundances. B: Nonmetric multidimensional scaling (NMDS) ordination of
WWTPs according to the ARG-based Bray–Curtis dissimilarities.
Ellipses enclose sites of noted similarities, ranging from 0 to 100
(perfect similarity); thus, ellipses with a similarity of 80 represent
sites with highest similarity. C: Relative abundance
of the top 20 bacterial phyla in WWTP influents. Genus-level annotations
were done via MG-RAST using the RefSeq database. D: NMDS
ordination of WWTPs according to Euclidian distances between rlog-transformed
reads to bacterial genera. Ellipses enclose sites of noted distances,
where the shortest distance denotes the highest resemblance, and the
longest distance denotes the least resemblance among the sites. Sample
names refer to countries (IND: India, PHL: Philippines, USA: United
States, CHE: Switzerland, HKG: Hong Kong, SWE: Sweden) along with
the visit number (1,2) and WWTP plant number (P).