Microplastics play an active role in promoting the evolution of antibiotic-resistant bacteria. Even in the absence of antibiotics.
Indigestible pollutants of seas, fish and water to drink; risk factors for tumors, dementia, cardiovascular problems and infertility; zattere for the transport of antibiotic resistant bacteria. Microplastics damage health in many ways, and a study by the American society of microbiology has just discovered another. In addition to passively transport superbatters from one corner to the other of the planet, such as inert taxi, Microplastics actively favor the selection of antibiotic-resistant bacteria. Even if the antibiotic is not present at that moment.
By facing plastic pollution we would therefore get the collateral advantage of fighting the problem of antimicrobial resistance (Antimicrobial ResistanceAmr), one of the main challenges for global health, directly responsible, in 2019, of 1.27 million global deaths.
Live evolution. In the new study, a group of researchers coordinated by Neila Gross, researcher of the Muhammad Zaman biomedic engineering laboratory, professor of Boston University, studied the interactions between three common types of microplastics and the bacterium Escherichia coli.
For 10 days, the microorganism was let it incubate with microfractments of polystyrene (the polystyrene used in packaging), polyethylene (used in the closable plastic bags) and of polypropyleneused for bottles and jars. The microplastics were long from half a millimeter to 10 micrometers.
Less vulnerable. Every two days, scientists controlled the lowest concentration of antibiotic that would have been necessary to inhibit the growth of the bacterium – what experts call Mic, minimum inhibitory concentration – Using four very common antibiotics. After only 5-10 days of exposure to microplastics, theE. coli he had strengthened his qualities of resistance to all four antibiotics (Ampicillin, Ciprofloxacin, Doxicicline and Streptomycin). Higher concentrations were needed to neutralize it than normal.
Active protagonists. The discovery is relevant because most of the previous studies had focused on the resistance induced by the wrong or excessive use of antibiotics, without considering the role of environmental pollutants. To tell the truth, the microplastics encouraged antibiotic-resistance actively even when antibiotics were not physically present next to the bacterium.
The induced resistance was significant, measurable and stable even after antibiotics and microplastics themselves have been removed from the sample. The complex habitat provided by microplastics has contributed to selecting the genotypical and phenotypic traits that support antibiotic resistance.
«This questions the idea that microplastics are simply passive carriers of resistant bacteria and underlines their role of active hotspots For the evolution of antimicrobial resistance “concludes Gross.
