Tracking Chlamydia\nand Syphilis in the Detroit Metro\nArea by Molecular Analysis of Environmental Samples

This paper describes one of the first studies applying\nwastewater\nsurveillance to monitor Chlamydia and Syphilis and back-estimate infections\nin the community, based on bacterial shedding and wastewater surveillance\ndata. Molecular biology laboratory methods were optimized, and a workflow\nwas designed to implement wastewater surveillance tracking Chlamydia\nand Syphilis in the Detroit metro area (DMA), one of the most populous\nmetropolitan areas in the U.S. Untreated composite wastewater samples\nwere collected weekly from the three main interceptors that service\nDMA, which collect wastewater and discharge it to the Great Lakes\nWater Authority Water Resource Recovery Facility. Additionally, untreated\nwastewater was also collected from street manholes in three neighborhood\nsewersheds in Wayne, Macomb, and Oakland counties. Centrifugation,\nDNA extraction, and ddPCR methods were optimized and performed, targeting Chlamydia trachomatis and Treponema\npallidum, the causative agents of Chlamydia and Syphilis,\nrespectively. The limit of blank and limit of detection methods were\ndetermined experimentally for both targets. Both targets were detected\nand monitored in wastewater between December 25th, 2023, and April\n22nd, 2024. The magnitudes of C. trachomatis and T. pallidum concentrations observed\nin neighborhood sewersheds were higher as compared to the concentrations\nobserved in the interceptors. Infections of Chlamydia and Syphilis\nwere back-estimated through an optimized formula based on shedding\ndynamics and wastewater surveillance data, which indicated potentially\nunderreported conditions relative to publicly available clinical data.