antibiotic

Microplastics and antibiotic resistance

April 14, 2025 By EarthWise Leave a Comment

Microplastics are a real problem. They are pretty much everywhere. They are in our food, in the oceans, on mountains, up in the clouds, and most alarmingly, in our bodies. All of that is already bad news, but researchers at Boston University have found that microplastics may also be contributing to antibiotic resistance in dangerous bacteria.

The researchers observed that bacteria exposed to microplastics become resistant to multiple types of antibiotics commonly used to treat infections. Bacteria can become resistant to antibiotics for a number of reasons, including misuse and overprescribing of medications. However, a major factor influencing antibiotic resistance is the microenvironment – the immediate surroundings of a microbe – which is where bacteria and viruses replicate.

The Boston University study tested how the common bacterium E. coli reacted to being in a closed environment with microplastics. The plastics provide a surface that the bacteria can attach to and colonize. When attached to a surface, bacteria create a sticky substance called a biofilm that acts like a shield, protecting the bacteria and keeping them affixed securely. The tests showed that microplastics supercharged the biofilms so much that when antibiotics were introduced, they were unable to penetrate the shield.

Microplastics are everywhere, but they are especially prevalent in impoverished places where sanitation may be limited. Refugees, asylum seekers, and forcibly displaced populations are already at increased risk of contracting drug-resistant infections. The prevalence of microplastics adds another risk to the already difficult lives of these people.

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Microplastics Could Be Fueling Antibiotic Resistance, BU Study Finds

Photo, posted May 15, 2021, courtesy of Felton Davis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A New Kind Of Antibiotic | Earth Wise

March 10, 2020 By EarthWise Leave a Comment

Antimicrobial resistance is a serious and growing problem for public health. Over time, more and more types of bacteria have become resistant to known antibiotics making it very difficult to treat various kinds of infections.

A new group of antibiotics with a unique approach to attacking bacteria has been discovered at McMaster University in Canada, representing a promising new clinical approach in the fight against antimicrobial resistance.

The newly found corbomycin and the lesser-known complestatin have a never-before-seen way to kill bacteria, namely, breaking the function of the bacterial cell wall. Bacteria have a wall around the outside of their cells that gives them shape and is a source of strength. Antibiotics like penicillin kill bacteria by preventing building of the wall, but the new antibiotics work by doing the opposite – they prevent the wall from being broken down. Breaking down the cell wall is critical for cells to divide. In order for bacteria to grow and spread, they need to expand and divide. By completely blocking the breakdown of the wall, it is as if the bacterium is trapped in a prison and can’t expand or grow.

The researchers demonstrated in mice that these new antibiotics can block infections caused by the drug resistant Staphylococcus aureus which is a group of bacteria that can cause many serious infections.

The researchers believe this new approach can be applied to other antibiotics and lead to the discovery of new ones with different mechanisms of action. This study found one completely new antibiotic, but since then, they have found a few others in the same family that have this same new mechanism.

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Antibiotics discovered that kill bacteria in a new way

Photo, posted March 15, 2012, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Drugs In The Water

April 15, 2019 By EarthWise Leave a Comment

According to a new study published in the journal Environmental Research Letters, concentrations of pharmaceuticals in rivers and lakes have dramatically increased across the globe over the past 20 years.

Traces of medicines get passed into waterways through the excretion of active drugs in human waste, the disposal of unused medicines down drains, and runoff from livestock farms.

The study looked in detail at two specific drugs: carbamazepine, an anti-epileptic drug, and ciprofloxacin, an antibiotic. The study found that the risk of ecological damage from the residue from these two drugs was 10 to 20 times higher in 2015 than in 1995.

Chronic exposure to carbamazepine, for example, has been shown to alter feeding behavior and reduce egg viability in zebrafish, as well as reduce reproductive success in crustaceans. Antibiotics can alter major nutrient cycles and decrease the effectiveness of bacteria-based wastewater treatment systems.

The study, led by researchers from the Netherlands, created a new model estimating concentrations of the two drugs over a 20-year period in 449 aquatic systems around the globe. The model predicts a relatively high environmental risk in densely populated and dry areas such as the Middle East.

When the researchers compared the model’s results to samples from four river systems in various locations, they found that the actual drug concentrations were even higher than model results, in some cases by a factor of 10 to 100.

The new model should act as a guide for a more thorough investigation into pharmaceutical residues in waterways, which pose significant environmental risks all over the world.

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