Trick or Treat: Can Superbacteria Exist in Our Seafood?

Superbacteria are an important health issue. That is because they survive treatment with several bacteria-killing drugs, called antibiotics. When antibiotics do not kill bacteria, it is harder to treat infections, and even simple infections can become fatal. Although superbacteria are widely studied in hospitals, their presence in the environment remains underexplored. In this article, we will tell you about a type of bacteria called Shewanella, which we found in sea urchins. Sea urchins are often eaten in many countries. We found that some samples of Shewanella from sea urchins could survive antibiotics. The presence of antibiotic-resistant bacteria in seafood tells us that these superbacteria do not only exist in hospitals, and our finding highlights the need to address the serious health issue posed by superbacteria.


WHAT ARE ANTIBIOTICS?
In the past, sicknesses caused by bacteria used to kill many people. Even simple infections, like sore throats, could be fatal. That is because INFECTIONS Invasion of the body by microorganisms, such as bacteria, that can escape the body's defense system and cause disease. people did not know what caused infections, nor how to treat them. Without treatment, infections could quickly get worse and spread to other body parts, leading to serious health problems and even death. Eventually, scientists started to identify microorganisms, and only then were those tiny creatures discovered to be the cause of many infections.

In
, a scientist named Alexander Fleming was studying a type of bacteria that causes infections in humans. In one of his experiments, a fungus accidentally grew next to the bacteria. He observed that the bacteria could not grow in the area surrounding the fungus. In other words, he found out that a specific fungus inhibited bacterial growth. This was important because what Fleming saw led to the discovery of substances that we now call antibiotics. He later found out that some ANTIBIOTICS Medications used to treat bacterial infections by killing or preventing the growth of bacteria.
fungi are able to produce penicillin, the first antibiotic to be discovered. Penicillin made it possible to treat many infections and save millions of lives. Because of this huge discovery, Fleming received a Nobel Prize in [ ].

WHAT DOES ANTIBIOTIC RESISTANCE MEAN?
We use antibiotics to treat infections caused by many bacteria. These medicines help to save millions of lives all around the world. Yet, antibiotics have often been used in an excessive manner, both in humans and other animals. Sometimes these drugs are used when they do not need to be. For example, since they only kill bacteria, antibiotics do not work on infections caused by other microorganisms, such as viruses. Overuse and misuse of antibiotics can trigger antibiotic resistance. But how?
When we use antibiotics to treat infections, we hope that the bacteria will die and that we will recover. But because we have been using the same antibiotics over and over again, sometimes unnecessarily, some bacteria have found ways of surviving in the presence of antibiotics, even when those drugs are used in large amounts! Scientists call bacteria that can survive the e ects of antibiotics plasmids. By doing that, the natural bacteria in the water may also become antibiotic resistant. But how can this a ect us?
In aquatic environments, we can find bacteria free-living in the water or living in or on marine animals. Some aquatic bacteria may make us sick after we go swimming or eat seafood. These infections usually do not spread or cause long-term e ects, so they are not generally a threat to healthy people. However, with the spread of superbacteria, infections may become much harder to treat with antibiotics, even in healthy patients! This means that common activities, such as eating seafood, could eventually lead to greater health risks (Figure ) [ ].

WHAT KIND OF SUPERBACTERIA ARE FOUND IN SEAFOOD?
To find out if seafood can carry superbacteria and how this can be a risk to human health, we studied a very peculiar animal: the sea urchin, collected in the waters of the Crozon peninsula in France. This area is famous for its beaches and fresh seafood, and it attracts many visitors, especially in the summer. Sea urchins are commonly eaten in Europe, and many people do not think that eating them could be a risk to their health. We studied a type of bacteria called Shewanella, which are commonly found in water or living in the guts of marine animals. Although generally harmless to humans, Shewanella can sometimes lead to infections of the intestines, blood, or existing wounds [ ]. We asked if Shewanella could survive antibiotics and, if so, whether they carry plasmids that could be passed on to other bacteria ( Figure ).
Shewanella are not usually considered superbacteria, but, to our surprise, most of the Shewanella that we tested survived the antibiotics used to treat infections, meaning they were resistant (superpowers detected!) [ ]. Curiously, four samples of bacteria survived even when we used three or more di erent antibiotics, meaning that some Shewanella are superbacteria, and any infection they cause would kids.frontiersin.org April | Volume | Article | be challenging to treat. When we investigated Shewanella's DNA, we found pieces of information that help bacteria survive antibiotics. We also noticed that many bacteria were carrying plasmids. Some could carry up to eight plasmids in just one tiny bacterial cell! That is a lot of plasmids, especially when we know that some bacteria do not have any. The presence of plasmids means that super-Shewanella can pass their resistance superpowers to other bacteria.

WHAT CAN WE DO?
In summary, antibiotic resistance is a threat to human health, and aquatic bacteria can help to spread it. Although most Shewanella are harmless, our experiments showed that some can survive antibiotics and even spread antibiotic resistance. Most people do not realize that seafood can be a source of superbacteria, or that if someone eats sea urchins containing Shewanella, they might also be consuming antibiotic-resistant bacteria. This might also be true for other microbes and other kinds of seafood. These superbacteria can cause infections that are extremely di cult to treat, because many drugs will no longer be useful to fight the infections. Superbacteria are especially dangerous for people whose bodies already have trouble fighting o infections, like the elderly and people with certain chronic diseases like diabetes and asthma.
So, what can we do to tackle this problem? It is becoming more di cult to find new antibiotics, so instead we must do our best to slow down the spread of superbacteria. One of the most important ways to do this is to use antibiotics properly-only when it is necessary and when prescribed by a doctor. Good hygiene habits and basic sanitation also prevent superbacteria from reaching aquatic environments and causing infections. Together, these actions can help us control the spread of superbacteria in humans, animals, and the environment.

CONFLICT OF INTEREST:
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
COPYRIGHT © Canellas, Barbosa, Costa and Laport. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

AUTHORS
ANNA LUIZA BAUER CANELLAS I am currently a master's student in microbiology at the Universidade Federal do Rio de Janeiro (UFRJ). I am interested in learning how environmental bacteria become resistant to antibiotics and if they can spread this trait to other bacteria. Currently, my research in the Marine and Molecular Bacteriology Laboratory (UFRJ) focuses on studying aquatic bacteria. My goals include determining if these bacteria are antibiotic resistant, if they can colonize seafood, and whether they have the potential to cause infections in humans. By learning more about environmental bacteria, we can better estimate the risks they pose to human health and help prevent infections and outbreaks.
MARIANA ANJO BARBOSA I am currently an undergraduate student in microbiology and immunology at the Universidade Federal do Rio de Janeiro (UFRJ). Additionally, I am an intern at the Medical Microbiology Research Laboratory, also in UFRJ. Currently, I am involved in a research project focused on studying specific bacteria isolated from human infections and their resistance to antibiotics. This investigation also involves analyzing some potential factors that could be associated with their antibiotic resistance or the lack of resistance.
WELLINGTON FELIPE DA COSTA I received my bachelor's degree at the Cândido Rondon University Center ( ), master's in microbiology from the Universidade Federal do Rio de Janeiro (UFRJ; ), and I am currently a doctoral student in microbiology at UFRJ. I have been studying antibiotic resistance in bacteria isolated from aquatic environments. My kids.frontiersin.org April | Volume | Article | goal is to understand how these bacteria end up in rivers and seas, whether they can be a risk to human health, and how we can fight them. My scientific investigations are carried out at the Marine and Molecular Bacteriology Laboratory (UFRJ).

MARINELLA SILVA LAPORT
I obtained a bachelor's degree in biomedicine ( ) at the Universidade Federal do Estado do Rio de Janeiro and a Ph.D. degree ( ) at the Universidade Federal do Rio de Janeiro (UFRJ). I completed my post-doctoral work at the FioCruz ( ) and at the Université Libre de Bruxelles ( -). I have been an associate professor at the UFRJ since . Currently, I develop and coordinate research activities in the Marine and Molecular Bacteriology Laboratory at the UFRJ. My research focuses on symbioses of microorganisms with marine organisms and the presence of potentially pathogenic and antibiotic-resistant bacteria in the aquatic environment. *marinella@micro.ufrj.br