The Hidden Journey of Superbugs in Our Waterways

In the heart of Columbus, Ohio, a silent battle is unfolding in the city's waterways. This battle is not fought with weapons, but with tiny, invisible warriors known as Carbapenemase-producing Enterobacterales, or CPE for short. These superbugs have become a significant threat in hospitals, but they don't stop there. They can also be found in the guts of healthy people, lurking in the community. CPE are tough survivors. They can hitch a ride in municipal wastewater, making their way to treatment plants. While treatment plants do a good job of reducing their numbers, they can't eliminate them entirely. This means that CPE can end up in nearby rivers and lakes, spreading into the environment. To understand this journey, researchers collected samples from various points in the water cycle. They looked at untreated wastewater, treated wastewater, and nearby surface waters over a year. They also examined sediment, fish, mammals, waterfowl, crops, and soil from the downstream watershed. The results were eye-opening. CPE were found in every single sample of untreated wastewater and in most of the treated wastewater and surface water samples. The most common type of CPE found was Enterobacter spp. , expressing the blaKPC-2 genotype. However, other species and genotypes were also present. The concentration of blaKPC was highest in the untreated wastewater, but treatment reduced it significantly. Interestingly, CPE were found in the intestines of some fish, but not in terrestrial wildlife. This study sheds light on how CPE can spread from healthcare settings into the natural environment via wastewater discharge. It suggests that rivers can act as reservoirs for these superbugs, allowing them to spread among surface water, wildlife, agriculture, and ultimately back to humans. This is a stark reminder of the interconnectedness of our environment and the importance of understanding and addressing these issues.