Apart from teeth, sharks have another tool to kill their prey, deadly bacteria

Sharks’ finely serrated teeth and their ability to smell blood is fearsome enough, and now scientists have claimed that one can even get harmed by touching the skin of a shark—by bacterial infection.

 

According to recent research, sharks and redfish from shores off of Massachusetts to the Belize harbour colonies of deadly, drug-resistant bacteria like Staphylococcus and E. coli.

 

While there have been no reported infections from shark-related bacteria, the researchers caution that the growing prevalence of drug-resistant bacteria in all animals, land and sea, is alarming.

 

"The fact that we found drug-resistant bacteria, regardless of distance from shore or interaction with human influences, warrants concern. These bacteria could be pathogenic," Discovery News quoted Jason Blackburn, a scientist at Florida Atlantic University and a co-author of the study as saying.

 

The Staphylococcus, E. coli and 141 other drug-resistant species of bacteria swabbed from the genital cavity of about a dozen different species of shark and redfish were resistant to not only naturally-occurring antibiotics like penicillin, but also to synthetic drugs like ciprofloxacin and doxycycline. 

 

The resistant bacteria were found in sharks that swam close to shore, as well as sharks found far out to sea that should have had no direct interaction with humans.

 

The researchers do not know for sure from here are sharks and redfish acquiring these drug-resistant genes.

 

But Blackburn has a few theories—drugs given to humans could simply be excreted and eventually find their way into the ocean. Or bacteria in humans could acquire the resistance, be excreted, and then colonize fish that sharks eat, or the sharks, themselves.

 

Some antibiotics are routinely dumped into aquaculture to help prevent infections -- that could be a source for some of the resistance.

 

To be sure of the source, however, more testing will be necessary, said Blackburn.

 

However the fish acquired these deadly germs, they don't appear to have any effect on either sharks or humans, said Blackburn.

 

If a person is infected by these bacteria it would be very difficult for doctors to fight off the infection.

 

Sharks and redfish aren't the only organisms to test positive for harbouring drug-resistant bacteria, and aren't likely to be the last.

 

Last year another study found that some species of dolphins also harbour drug-resistant bacteria.

 

"You don't expect to see multi drug resistance from these animals because they shouldn't be exposed to antibiotics," said Adam Schaefer, a researchers at Florida Atlantic University who co-authored the new study.

 

The study has been published in the Journal of Zoo and Wildlife Medicine.