Some sharks harbor drug-resistant bacteria

CHAMPAIGN, Ill., June 16 (UPI) -- Scientists involved in a multi-university study say they have discovered several strains of antibiotic-resistant bacteria in seven shark and redfish species.

University of Illinois Professor Mark Mitchell, a senior author of the study, said most of the fish, captured in waters off Massachusetts, Florida, Louisiana and Belize, harbored several drug-resistant bacterial strains, but resistance to antibiotics that fish shouldn't be exposed to was found in every species and at nearly all of the study sites.

Among the animals sampled, nurse sharks in Belize and in the Florida Keys had the highest occurrence of antibiotic-resistant bacteria, including bacterial resistance to amikacin, ceftazidime, chloramphenicol, ciprofloxacin, doxycycline, penicillin, piperacillin, sulfamethoxazole and ticarcillin.

Random mutations might account for some drug-resistant bacteria in marine environments, Mitchell said, but there is significant evidence for a human origin.

The study that included former graduate student Jason Blackburn and researchers from Louisiana State University, the University of Florida and the University of Southern California appears in the Journal of Zoo and Wildlife Medicine,