Reducing Environmental Pollution by Antibiotics through Design for Environmental Degradation

The spread of antibiotic-resistant pathogenic bacteria is an increasing health issue worldwide. A possible origin of antibiotic resistance could be the persistence of antibiotics in the aquatic environment. To tackle this problem, restricted control of application of antibiotics in human and veterinary medicine has been proposed. However, these measures do not prevent the spread
of antibiotic resistance but may delay the process, since antibiotics are still continuously emitted into the environment and many persist there. Derived from ciprofloxacin (CIP), CIP-Hemi, a fluoroquinolone with improved environmental properties, was developed following the benign by design approach and using in
silico and in vitro methods. CIP-Hemi was designed to maintain its required metabolic stability (human liver microsomes, intestinal microsomes, blood plasma) and antibiotic activity (MIC in the μg mL−1 range) against the target while transforming into an inactive fragment (CIP-d-CP) and a degradable linker present under acidic conditions, e.g., after excretion or when released into the
environment. Moreover, CIP-Hemi and CIP-d-CP showed weaker cytotoxic and mutagenic or genotoxic effects compared to the parent compound CIP and therefore underline the feasibility of CIP-Hemi as a viable antibiotic drug candidate, demonstrating benign by design as a promising approach.