Do monitoramento ao controle de Vibrio cholerae em águas residuais de Uberlândia - MG

Abstract

Infectious diseases kill millions annually. Diarrheagenic bacterial pathogens, including Vibrio spp., are responsible for a significant portion of these diseases, causing deaths and disabilities worldwide. The crucial role of environmental settings in the life cycle of bacterial pathogens is increasingly recognized. Wastewater-Based Epidemiology (WBE) is a valuable approach for community monitoring, with a proven track record of effectiveness in predictive outbreak sur-veillance. Uberlândia-MG, considered a model city for sanitation in Brazil, can highlight flaws that encompass locations with poor infrastructures, demonstrating its global applicability. Un-derstanding the prevalence and antimicrobial resistance of Vibrio cholerae is essential for miti-gating risks and developing new, effective control strategies. This study was divided into two chapters, with the first addressing the theoretical framework and presenting the state of the art of Vibrio spp. The second chapter features an article prepared for publication in the journal Water Research, which aimed to investigate epidemiological aspects and the phenotypic and genotypic characteristics of V. cholerae in urban wastewater from Uberlândia-MG, as well as to evaluate the effectiveness of magnetic graphene oxide (MGO) as a control method for this pathogen. A high prevalence of Vibrio spp. (62.33% - 48/77) was observed, particularly V. cholerae (44.15% - 31/77), which also remained predominant after treatment (84.6% - 22/26). A total of 24.65% (18/73) of V. cholerae strains were ctxAB+ tcpA- and classified as non-toxigenic. The tox and hlyA genes were detected in 100% of the strains (73/73), while rtx and ompU were present in 95.89% (70/73) and 34.24% (25/73), respectively, with ompU being exclusive to the Uber-abinha wastewater treatment plant. Seven virulence profiles were identified, and the Mean Viru-lence Gene Index (MVGI) had an average of 0.31 ± 0.13. Phenotypic resistance was evaluated using minimum inhibitory concentration (MIC) tests. All strains were sensitive to MEM and CAZ. High resistance levels were detected for SUL (MIC50 = >512 μg/mL, 81.08% - 30/37), followed by AZM (MIC50 = 2 μg/mL, 51.31% - 19/37), and DOX (MIC50 = 4 μg/mL, 21.62% - 8/37). For MGO-47, the average MIC was 15 μg/mL, lower than those identified for AMP, GEN, CHL, and SUL. Fifteen resistance profiles were identified, one of which exhibited the highest Multiple Antibiotic Resistance Index (MARI) (0.77), with resistance to seven classes of antibiotics. Biofilm formation was evident in all strains, with varying intensity. Supplementa-tion with wastewater and chitin reduced biofilm biomass. Co-culture with E. coli resulted in an increase of 0.33 in Biofilm Formation Index (BFI) and a biofilm with mature ultrastructure ob-served via scanning electron microscopy. V. cholerae O139 strains were confirmed via sequenc-ing, with up to 147 virulence genes, along with resistance genes and mobilizable and non-mobilizable plasmids derived from other species. We believe the data generated by our study are relevant for microbial risk assessment of Vibrio spp. and support the development of environ-mental regulations that will help prevent cholera and vibriosis outbreaks, especially serving as a model for cities with poorer sanitation infrastructure.