June 13, 2022 | Erin Bluvas, firstname.lastname@example.org
Individuals living with chronic multisymptom illness (CMI) – such as older adults and veterans with Gulf War Illness (GWI) – suffer from a host of inflammation-related symptoms and complaints (e.g., headaches, cognitive difficulties, neuroinflammation, fatigue, widespread pain, respiratory problems, sleep problems, gastrointestinal problems, other unexplained medical abnormalities). Numerous studies have confirmed that antibiotic resistance belongs on that list as well.
Projected to account for more deaths than cancer and AIDS combined by 2050, antimicrobial resistance is a growing threat to public health. Previously reliable treatments for bacterial infections are becoming less and less effective as bacteria develop stronger resistance to most available antibiotics.
Researchers from across the Department of Environmental Health Sciences (ENHS), UofSC and other universities, have shed even more light on the mysterious and debilitating condition of CMI and, in particular, its association with antibiotic resistance. Their recent study, which was directed by ENHS professor Saurabh Chatterjee and published in Nature’s Communication Biology journal, investigated the underlying elements that impact antibiotic resistance within this population. The project was led by Dipro Bose, a student in the Ph.D. in ENHS program and winner of the 2022 UofSC Breakthrough Scholar Award.
“Resistance to currently approved antibiotics occurs when antibiotic resistance genes, which are carried by pathogens, collectively form something called a resistome,” Chatterjee says. “The human gut serves as a good home for a reservoir of these genes and is also conducive to their transfer – often through the assistance of mobile genetic elements – which sometimes lead to the emergence and spread of a new strain. Environmental influences such as pesticides and antibiotics further alter the microbiome, resulting in increased antibiotic resistance among individuals, like GWI veterans, who have had these exposures.”
Affecting 25-32 percent of the 700,000 U.S. veterans who served between 1990 and 1991, GWI research is hardly in its infancy. Yet two decades of studying the condition failed to fully reveal exactly how it affects the body and how to treat it.
This stagnation lifted around the time Chatterjee came on the scene in 2012, joining the Arnold School for his first academic appointment and establishing his the Environmental Health & Disease Laboratory (also known as the Chatterjee Lab) with an $800,000 NIH Pathway to Independence Award to study how environmental toxins contribute to liver disease, metabolic syndrome and obesity. Over the ensuing decade, Chatterjee was awarded $8.4 million in federal funding – with $6 million and countless hours devoted to advancing GWI research.
One of the milestones in this work includes the team’s discovery that GWI-altered microbiomes produce endotoxins that circulate throughout the body. The groundbreaking 2017 study revealed that this pathway was how GWI caused neurological symptoms – a key understanding that had eluded scientists for years. Chatterjee and his lab have uncovered additional insights into GWI, including the use of over-the-counter probiotics and ancient herbal medicine, androgapholide, as possible treatments for the condition as well as the enhanced vulnerability to COVID-19 faced by veterans with GWI.
This latest study expands GWI understanding even further by overlapping with the domain of antimicrobial resistance. Chatterjee teamed up with fellow ENHS professor and long-time collaborator Alan Decho, whom he has worked with to extend the research involving antimicrobial resistance and its interactions to environmental exposures as part of the Oceans and Human Health Center on Climate Change Interactions. Together they examined the heightened antibiotic resistance faced by the veteran population – as evidenced by the altered resistome and antibiotic resistant genes as well as the array of mobile genetic elements that likely facilitated and accelerated these altered states.
“Antimicrobial resistance has been traced to some of the most commonly used antibiotics, such as tetracyclines and macrolides,” says Chatterjee. “These antibiotics are crucial in treating some hospital acquired infections, which makes the findings from this study essential to helping clinicians better understand the risks to treating these types of infections among those with CMI/GWI.”