Nanoplastics　(NPs)　and　quaternary　ammonium　compounds　(QACs)　are　frequently　detected　in　sewage.　However,　little　is　known　about　the　risks　of　coexistence　of　NPs　and　QACs.　In　this　study,　the　responses　of　microbial　metabolic　activity,　bacterial　community　and　resistance　genes　(RGs)　to　the　exposure　of　polyethylene　(PE),　polylactic　acid　(PLA),　silicon　dioxide　(SiO2)　and　dodecyl　dimethyl　benzyl　ammonium　chloride　(DDBAC)　were　focused　on　2nd　and　30th　day　of　incubation　in　sewer　environment.　Bacterial　community　contributed　25.01　%　to　shape　RGs　and　mobile　genetic　elements　(MGEs)　after　two　days　of　incubation　in　sewage　and　plastisphere.　After　30　days　of　incubation,　the　most　important　individual　factor　(35.82　%)　was　turned　to　microbial　metabolic　activity.　The　metabolic　capacity　of　the　microbial　communities　in　plastisphere　was　stronger　than　that　from　SiO2　samples.　Moreover,　DDBAC　inhibited　the　metabolic　capacity　of　microorganisms　in　sewage　samples,　and　increased　the　absolute　abundances　of　16S　rRNA　in　plastisphere　and　sewage　samples　which　might　be　similar　to　the　hormesis　effect.　After　30　days　of　incubation,　Aquabacterium　was　the　predominant　genus　in　plastisphere.　As　for　SiO2　samples,　Brevundimonas　was　the　predominant　genus.　QACs　RGs　(qacEdelta1-01,　qacEdelta1-02)　and　antibiotic　RGs　(ARGs)　(aac(6′)-Ib,　tetG-1)　significantly　enriched　in　plastisphere.　There　was　also　co-selection　among　qacEdelta1-01,　qacEdelta1-02　and　ARGs.　In　addition,　VadinBC27　which　enriched　in　plastisphere　of　PLA　NPs　was　positively　correlated　with　the　potentially　disease-causing　genus　Pseudomonas.　It　showed　that　after　30　days　of　incubation,　plastisphere　had　an　important　effect　on　distribution　and　transfer　of　pathogenic　bacteria　and　RGs.　Plastisphere　of　PLA　NPs　also　carried　the　risk　of　spreading　disease.　©　2023　Elsevier　B.V.