Antibiotic resistance (also called antimicrobial resistance) is a global threat, and India is among the worst affected countries.
According to a July 2024 report Lancet article, the AR burden in India is “particularly high”. “Growing resistance to existing antibiotics amid the shrinking pipeline of newer medicines poses a serious threat to achieving the SDG target (the UN Sustainable Development Goals) by 2030,” the report said.
Now, a study from the Institute of Nano Science and Technology, Mohali, has revealed a hitherto unknown cause of AR: nanoplastics.
Nanoplastics, from single-use plastic bottles, contribute to the spread of AR, the study found, underscoring an unrecognized risk to public health.
The joint threat of plastic pollution and antibiotic resistance is a growing concern. Nanoplastics and microorganisms coexist in diverse environments, including the human intestine.
This problem led INST scientists to investigate how plastic nanoparticles can affect bacteria.
Recognition of the central role of Lactobacillus acidophilus in the intestinal microbiota, Dr. Manish Singh and his team whether nanoplastics could transform beneficial bacteria into carriers of AR genes and pose a risk to the health of the human gut microbiome.
They synthesized nanoplastic particles from used plastic water bottles because they better represent the actual polluting nanoplastics that come from discarded single-use plastic bottles and containers.
The scientists have shown that nanoplastics derived from polyethylene terephthalate (PET) bottles can facilitate interspecies gene transfer from E coli to other species. Lactobacillus acidophilus through a process called horizontal gene transfer (HGT), specifically through the secretion of outer membrane vesicles (OMV) in bacteria.
Gene transfer mechanism
According to the researchers, there are two new mechanisms by which nanoplastics from PET bottles facilitate the transfer of AR genes.
The first is via a direct transformation route, where the nanoplastics act as physical carriers, transporting AR plasmids across bacterial membranes and promoting direct gene transfer between bacteria.
The second is through the OMV-induced transfer pathway, where the nanoplastics cause oxidative stress and damage to bacterial surfaces, which activates the stress response genes and causes an increase in OMV secretion.
The OMV loaded with AR genes becomes a powerful vector for gene transfer between bacterial species, facilitating the spread of AR genes even among unrelated bacteria.
“This reveals an important and previously overlooked dimension of the effects of nanoplastics on microbial communities,” the publication said.
The study, published in the journal Nanoscalehighlights how nanoplastics may unexpectedly contribute to the AR crisis by introducing AR genes into beneficial gut bacteria such as Lactobacillus acidophiluswhich could act as reservoirs for AR genes and potentially transfer them to pathogenic bacteria during infections.
Protecting beneficial gut bacteria is crucial for immune support, digestion and disease prevention.
Limiting nanoplastic contamination may help maintain the integrity of the gut microbiota, minimizing the chances of AR gene transfer from beneficial to pathogenic bacteria and supporting microbiome resilience.
With plastic pollution on the rise, this finding highlights the need for strict safety guidelines, awareness programs and policies that prioritize responsible plastic use and waste management to protect human health and microbiome stability.
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Published on December 29, 2024