Dolphins are one of those endangered species who have recently provided insightful learning about the resistance of antibiotics in humans. In the bottlenose dolphins, 88% of the pathogenic organisms show resistance to one or more antibiotics.
It is an alarming situation for the researchers as well as humans. The researchers said that the same phenomenon could happen in humans as well. The bottlenose dolphins are sentinel species that is; they indicate future environmental risks for humans.
The findings of the research appear in the journal Aquatic Mammals.
Humans may show antibiotic resistance for Erythromycin and Ampicillin in the future
Researchers used data from 171 bottlenose dolphins collected over 13 years. In this time frame, they found 733 pathogens in them and some of them also affect humans too.
92% of the organisms showed resistance to erythromycin while 77% by ampicillin. Erythromycin and ampicillin are two of those common antibiotics which people use in their daily lives.
Initially, the foreign bodies quickly responded to the antibodies. But as time passed by, the organisms started showing drug resistance. Previously, drug resistance was only observed in the disease centers but this has now become a global phenomenon.
According to an estimate, 2 million people every year show resistance to antibiotics and this costs them their life.
The first information about the adverse signs in the marine environment was observed in 2009. However, today, researchers acknowledge an increase in antibiotic resistance in wild dolphins.
Antibiotic resistance may have developed because of the constant use of antibiotics in human-populated zones. Up until now, only a few researchers have worked on the increasing trend of antibiotic resistance in mammals.
Under the rules of the Health and Environmental Risk Assessment, or HERA project, researchers collected samples over two periods that is; 2003-2007 and 2010-2015.
The study specifically focused on the bottlenose dolphins found in Florida’s Indian River Lagoon. Researchers chose this place as its coast is a human-occupied area.
In order to make up a resistance profile, they used data from bacterial isolation and multiple antibiotic resistance (MAR) index. They collected the data over a period of 13 years. Researchers collected the samples of the bacteria from feces, blowholes, and stomach fluid.
The isolated samples were then cultured, identified and tested to draw a graph of antibiotic resistance.
Possible causes of the increasing trend of antibiotic resistance
According to an interview with Adam M. Schaefer, the blame of the isolation of the antibiotics in dolphins goes to those places where these are commonly being used. The antibiotics may have entered their system from human activities or the terrestrial zone.
The sources may include discharge from the canals or septic tanks. Researchers isolated the species Aeromonas hydrophila, Edwardsiella tarda, S. aureus, E. coli, and V. alginolyticus.
They observed a high level of antibiotic resistance in the current study for Pseudomonas aeruginosa. The resistance greatly increased over a period of 13 years. This bacterium has the capability to trigger many infections including respiratory and urinary infections.
The MAR index also shows that the species Vibrio alginolyticus and Acinetobacter baumannii responsible for seafood poisoning and hospital infections respectively have gained resistance to an alarming rate.
The study shows that the resistant antibiotic strains of bacteria entering the marine system because of human activities are putting selection pressure on the normal bacteria. The resistant strains multiply rapidly, producing a large community of resistant pathogens.
Further increase in the drainage of antibiotics in the marine water and excessive use of antibiotics among humans may push the human population towards a world of deadly diseases in the future.