Antimicrobial resistance (AMR) is one of the foremost global public health challenges. Hospital effluents release resistant bacteria, resistance genes, and antimicrobial residues into aquatic ecosystems, fostering the spread of AMR. In this context, nature-based solutions (NbS), such as phytoremediation, have emerged as low-cost alternatives for mitigation. This study aimed to evaluate the potential of two aquatic plant species in removing antimicrobials, resistant bacteria, and carbapenemase genes from hospital wastewater.

Effluent samples were collected from a hospital in Lapa (Paraná) and subjected to three 10-L treatments in triplicate: EFL (effluent without plants), SAL (Salvinia molesta), and PTC (Pontederia crassipes). After seven days, samples were analyzed for antimicrobial residues (tetracyclines and beta-lactams) using the TwinSensor rapid test. Colony-forming units (CFUs) were quantified, resistant strains identified on ESBL agar, and carbapenemase genes (KPC, IMP, NDM, VIM, OXA-48) detected using Medomics rapid tests.

In the EFL group, antimicrobials were detected (tetracycline 80 µg/L, oxytetracycline 60 µg/L, amoxicillin 2 µg/L, penicillin 3 µg/L), along with KPC, IMP, and NDM genes. Resistant isolates included Klebsiella pneumoniae, Escherichia coli, Pseudomonas spp., and Proteus spp. Phytoremediation with S. molesta achieved complete removal of antimicrobials and resistance genes, total elimination of E. coli, and 99% reduction of other resistant species. P. crassipes achieved 100% beta-lactam removal, 56% tetracycline reduction, and partial gene suppression (IMP and NDM). Given that the hospital mainly treats respiratory diseases, these findings reinforce the relevance of NbS in preventing AMR dissemination into aquatic ecosystems and its implications for public health.

Phytoremediation proved to be an effective and innovative NbS for reducing microbial and genetic AMR load in hospital effluent. The results reinforce the contribution of this ecotechnology to the protection of public and environmental health.