G-2221

Detection of SARS-CoV-2, Influenza A and B, and RSV Genomes in Biofilms Formed in Hospital and Urban Wastewater Systems in Dezful, Iran

 Behnam Azizolahi ¹ ©, Fatemeh Riyahi Zaniani ¹, Zahra Rakian ² ℗, Mohammad Khordehbin ³, Fariba Soleimani Farsani ⁴   

 
Abstract

Introduction: Wastewater has emerged as a valuable medium for monitoring the spread of respiratory viruses. Biofilms present in wastewater systems may act as hidden reservoirs for viruses, playing a role in their persistence, potential transmission, and environmental recontamination. This study aimed to detect the RNA genomes of SARS-CoV-2, Influenza A and B viruses, and Respiratory Syncytial Virus (RSV) in biofilms formed within hospital and urban wastewater systems in …, Iran, and to assess their potential roles. Methods and Materials: In this descriptive study, 40 samples were collected during autumn 2023 from various wastewater sources in …, Iran, including hospital and urban wastewater systems. The samples included 15 liquid wastewater samples (eight from hospital and seven from urban sites) and 25 viscous samples suspected to contain biofilms (17 from hospital and 8 from urban sites). Gram staining and microscopic examinations were performed to confirm the presence of biofilms. Viral RNA was extracted using a commercial viral RNA extraction kit, and its quality was verified spectrophotometrically. TaqMan Multiplex Real-Time PCR was performed using the GA SARSFlu & RSV kit to detect the genomes of SARS-CoV-2, Influenza A and B, and Respiratory Syncytial Virus (RSV). Results: Of the 25 viscous samples, 20 were confirmed to contain biofilms: 16 from hospital wastewater and 4 from urban wastewater. All 15 liquid samples were negative for biofilm formation. Among the 20 biofilm-containing samples, one sample from the hospital wastewater tested positive for the SARS-CoV-2 genome. No viral genomes were detected in samples without biofilms, and no samples tested positive for Influenza A, Influenza B, or RSV. Conclusion and Discussion: The presence of viral RNA in biofilms suggests that they may serve as reservoirs for respiratory viruses in wastewater environments. This underscores the need for environmental monitoring of biofilm-associated pathogens, particularly in hospitals and urban sewage systems. Future research should explore virus–biofilm interactions and potential interventions to limit biofilm formation and enhance disinfection in high-risk areas.

Keywords: Wastewater, Biofilm, SARS-CoV-2, Influenza, RSV