The study, published in the Journal of Zoo and Wildlife Medicine, found antibiotic-resistant bacteria in every fish species sampled. The researchers also found multidrug-resistant bacteria in fish at nearly all of the study sites, said Mark Mitchell, a professor of veterinary clinical medicine at the University of Illinois and a senior author of the paper.
“Ultimately the idea of this study was to see if there were organisms out there that had exposures or resistance patterns to antibiotics that we might not expect,” Mitchell said. “We found that there was resistance to antibiotics that these fish shouldn’t be exposed to.”
Among the animals sampled, nurse sharks in Belize and in the Florida Keys had the highest occurrence of antibiotic-resistant bacteria. These sharks feed on crustaceans, small fish and other animals living in shallow waters close to shore.
Random mutations may account for drug-resistant bacteria in marine environments, Mitchell said, but there is a lot of evidence for a human origin.
“The shark population in Belize, for example, is a big tourist area, so there are people in the water right there,” he said. “The sampling site is not far from a sewage plant, and so all those exposures we think are playing a role.”
Sewage also is a problem in the Atlantic coastal waters of the United States, he said.
Previous studies have shown that sewage outflows can leak antibiotic-resistant bacteria into the environment.
In the new study, the researchers looked for and found bacterial resistance to 13 antibacterial drugs in the fish. Patterns of resistance varied among the sites. Bacteria from sharks off Martha’s Vineyard in Massachusetts and in offshore Louisiana were resistant to the fewest number of antibiotics, while sharks in the Florida Keys and Belize harbored bacteria that were resistant to amikacin, ceftazidime, chloramphenicol, ciprofloxacin, doxycycline, penicillin, piperacillin, sulfamethoxazole and ticarcillin.
Redfish in the Louisiana offshore site hosted more varieties of drug-resistance than sharks in the same waters. This may reflect differences in their age (the redfish were more mature than the sharks), feeding or migratory habits, Mitchell said.
While the presence of antibiotic-resistant bacteria in sharks and other fish does not necessarily harm them, Mitchell said, the findings point to a growing problem for human health.
“There are estimates of over 100,000 deaths from infections in hospitals per year, many of them from antibiotic-resistant organisms,” Mitchell said. “And we’re creating even more of these organisms out in the environment. … Unfortunately, as these things collect, there’s probably a threshold at some point where there’s going to be a spillover and it will start to affect us as a species.”
People do eat sharks and redfish, Mitchell said, and now these fish represent a potential new route of exposure to drug-resistant bacteria. Sharks and redfish also are predators, and so may function as sentinels for human health.
“Some people might say, well, a bull shark in offshore Louisiana doesn’t really have an influence on my health,” Mitchell said. “But these fish eat what we eat. We’re sharing the same food sources. There should be a concern for us as well.”
This study was the thesis for corresponding author Jason Blackburn, a former master’s student at Louisiana State University now on the faculty at the University of Florida. The team included researchers from LSU, the University of Florida, the University of Illinois and the University of Southern California.
Diana Yates | University of Illinois
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy