The present disclosure provides engineered genetic systems and methods to confer the ability to target and degrade undesirable nuclic acids in an organism so as to combat gastrointestinal, skin or urinary tract disease and infection, prevent the spread of antibiotic resistance, and/or decontaminate environmental pathogens. The engineered genetic system can also be used for the therapeutic treatment of humans and animals. The undesirable nucleic acids can be DNA and/or RNA.
