Bacteriophage survival and ARG dissemination from wastewater treatment plants to the environment

The proliferation of antibiotic resistance genes (ARGs) represents a critical global health threat, with wastewater treatment plants (WWTPs) identified as major hotspots for resistance amplification and dissemination. While bacterial conjugation has been extensively studied, bacteriophages are emerging as significant but underestimated vectors for ARG transfer via transduction. We hypothesize that phages are capable of withstanding disinfection and exploiting diverse bacterial hosts in receiving environments, thereby functioning as active vectors of ARG dissemination rather than passive genetic reservoirs. Meta-analysis of disinfection efficacy data (n = 79 experimental observations, 6 technology categories) reveals significant differences in log₁₀ reduction across disinfection technologies (Kruskal-Wallis: H = 25.96, df = 5, p < 0.0001). Ozonation was significantly more effective than chlorination (p < 0.001), membrane processes (p = 0.003), UV irradiation (p = 0.005), and PAA/thermal treatment (p = 0.010). Phage persistence in receiving waters follows a 1-4 week timeline modulated by temperature (Q₁₀ ~ 2-3), solar UV, and water chemistry. Broad host range phages have the potential to transfer ARGs to environmentally dominant genera (Aeromonas, Pseudomonas, Vibrio), and sub-inhibitory antibiotics may induce prophages and enhance bacterial competence, creating synergistic conditions that could accelerate resistome evolution. This review underscores the need for integrated approaches combining phage-targeted disinfection with ecological monitoring to effectively restrain the spread of antibiotic resistance.