California Sea Grant College Program

After years of antibiotic use, the normal flora in the human intestinal track can develop antibiotic resistance. If this happens, antibiotic-resistant (AR) bacteria, as well as AR genes, can be shed in feces. To the extent that raw sewage flows to the coast, and to the extent that sewage treatment processes do not destroy DNA, estuaries and other coastal wetlands are potentially the receiving waters for AR bacteria and genes. Because livestock are also