Distribution and resistance-associated genomic features of Acinetobacter in an urban wastewater network
Year: 2026
Type: article
Abstract: Acinetobacter spp. are important opportunistic pathogens with strong multidrug resistance potential, yet their distribution and associations with antibiotic resistance across urban wastewater systems remain poorly resolved. In this study, we characterized the spatiotemporal dynamics of Acinetobacter across an urban wastewater network including hospital, student residence hall, and wastewater treatment plant (WWTP) sites. A total of 300 wastewater samples were collected weekly over 1.5 years and analyzed by droplet digital PCR (ddPCR), with 94 samples further subjected to shotgun metagenomic sequencing. Acinetobacter was consistently detected across all sampling sites and ranked among the more abundant genera in site-pooled metagenomic community profiles. Throughout the WWTP treatment process, absolute Acinetobacter concentrations decreased by a median of 2.71 log₁₀ units from influent to effluent, coinciding with a reduced ratio of Acinetobacter to total bacterial 16S rRNA gene copies. Cross-validated differential abundance analyses (DESeq2 and ANCOM-BC2) of the metagenomes corroborated this significant reduction in the effluent. Despite this removal efficacy, treated effluent maintained an average Acinetobacter concentration of 9.19 × 10² copies/100 mL, and the genus persisted as a highly abundant member of the effluent microbiome. Notably, Acinetobacter showed a positive association with 16S-normalized total antibiotic resistance gene (ARG) abundance (ρ = 0.570) that robust even remained significant after covariate adjustment (partial ρ = 0.508; 95% CI, 0.321-0.662). Genome-resolved analysis recovered 20 medium-to-high-quality Acinetobacter metagenome-assembled genomes, revealing site-specific lineage variations and identifying seven distinct OXA β-lactamase gene sequences. Although acquired ARG carriage and mobility were not established, the combined analyses support Acinetobacter as a widely detected genus associated with the wastewater resistome. From a public health perspective, tracking Acinetobacter alongside ARGs can characterize treatment-associated changes, provide bacterial-community context for resistance signals, and inform targeted genomic follow-up.
Authors: Xin Li, Haodong Liu, Jianfeng Wu, Chuanwu Xi
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,680
OpenAlex ID: W7222972961