Bengali scientists nail down antibiotic-resistant ‘Superbugs’

Antibiotics provide effective treatment for a wide variety of infections and illnesses. Sir Alexander Fleming, a Scottish researcher, is credited with the discovery of penicillin in 1928. The introduction of penicillin in the 1940s, which began the era of antibiotics, has been recognized as one of the greatest advances in therapeutic medicine. The discovery of penicillin changed the world of medicine enormously. With its development, infections that were previously severe and often fatal, like bacterial endocarditis, bacterial meningitis, and pneumococcal pneumonia, could be easily treated.

However, the rise in the number of ‘Superbugs’ which are strains of bacteria, viruses, parasites, and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause, is a major cause of global concern. The danger of antibiotic resistance superbugs is that treatable illnesses, such as pneumonia, tuberculosis, urinary tract infections, skin infections or minor infections could become incurable. 

Multi-drug resistant bacteria - triggered by rampant and injudicious use of antibiotics - are on the rise. They're affecting more than half of the patients across hospitals and can lead to a crisis unless measures are taken immediately to identify the bacteria and regulate the prescription of antibiotics. Antimicrobial resistance is a growing public health concern around the world. Resistance has emerged even to newer and more potent antimicrobial agents like Carbapenems. The rapid spread of multi-drug-resistant bacteria and the lack of new antibiotics to treat infections caused by these organisms pose a rapidly increasing threat to human health. Drug resistance (antimicrobial resistance) is a naturally occurring phenomenon that can be slowed, but not stopped. Over time, germs such as bacteria, viruses, parasites, and fungi adapt to the drugs that are designed to kill them and change to ensure their survival. This makes previously standard treatments for some infections less effective, and sometimes ineffective. Researchers continue to evaluate how these germs develop resistance. They also study how to diagnose, treat and prevent antimicrobial resistance.

Recently, a team of seven scientists including three Bengali researchers made a breakthrough in identifying the superbug. The team comprising Dr. Souvik Bhattacharya, chief researcher of the project from the Department of Molecular Biosciences and LaMontagne Center for Infectious Diseases, the University of Texas at Austin along with Dr. Madhumita Bhattacharya of the Technical University of Munich, Augsburg, Germany, Anjan Kumar Nandy Senior Research Scientist at Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata, Dylan M Pfannenstiel, Undergraduate Assistant, the University of Texas at Austin (UT), Yunesahng Hwang, Graduate Research Assistant Molecular Biosciences, College of Natural Sciences, the University of Texas at Austin, Khang Ho, Graduate student of the University of Texas at Austin and Dr. Rasika M. Harshey, Professor, Molecular Biosciences at the University of Texas at Austin, started working on the common E.coli bacteria in 2019. 

In a study titled, ‘Efflux-linked accelerated evolution of antibiotic resistance at a population edge,’ the team explains that efflux is a common mechanism of resistance to antibiotics and efflux itself promotes a phenomenon called ‘adaptive resistance,’ in which many bacterial swarms display an accumulation of antibiotic-resistance mutations (ARMs). High efflux is linked to the downregulation of DNA repair and is therefore mutagenic. The team discovered the process of ‘necro signalling’ where dead cells of an E. coli swarm population release a periplasmic protein AcrA that binds to the outer membrane protein TolC of live cells within the same population. This binding acts as a signal to increase the activity of efflux pumps which contributes to the establishment of adaptive resistance to various antibiotics. So, the scientists realized they needed to work on inhibitors that aim to decrease the evolvability of antibiotic resistance. 

Each of the team members individually carried out extensive experiments on 16,000 specimens and they all concluded that the way to target efflux and decrease its evolvability to antibiotic resistance is to use two sets of medicines simultaneously – one would be the usual antibiotic and the other medicine would be targeted to destroy the functionality of ‘influx pump.’ Scientists have found enzyme inhibitors to work very well in these cases. An enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity. The research team is happy with the results and is hopeful that new medicines will be available to tackle superbugs shortly that will save billions of lives globally.