
Probiotics Could Offer Important Line of Defense Against Drug-resistant Bacteria
As the rise of antibiotic-resistant bacteria leads to higher rates of life-threatening infections from pathogens such Clostridium difficile and methicillin-resistant Staphylococcus aureus (MRSA), researchers are increasingly looking to probiotic treatment as an important part of fighting infections.
As the rise of antibiotic-resistant bacteria leads to higher rates of life-threatening infections from pathogens such
Since the 1940s, antibiotics have been a key line of defense against dangerous infections. Over time though, as antibiotic use has grown, the pathogenic bacteria they’re designed to attack have adapted and developed drug resistance, giving rise to “superbugs” such as C. Difficile and MRSA, now culprits in so many
“Unlike conventional drugs, commensal bacterial species have coevolved with us and are a normal part of the human superorganism,” writes Dr. Pamer in his paper. “Indeed, these microbial populations are the product of tens of millions of years of co-evolution with humans, and thus their safety might be considered well established. Indeed, it is their absence that is associated with susceptibility to a wide range of infections.”
The review paper highlights studies showing that reestablishing microbiota-mediated colonization resistance after antibiotic treatment could markedly reduce infections, particularly those caused by antibiotic-resistant bacteria.
Intestinal microbiota work to create colonization resistance to pathogenic bacteria in my ways, and the studies Dr. Pamer cites in his paper highlight the complex chemical balance of the gut. For example, C. scindens, an obligate anaerobic bacterial species that inhabits the colon, has the rare ability to convert primary to secondary bile salts, which are highly associated with resistance to C. difficile colitis in mice and humans. Administration of C. scindens to susceptible mice corrected the deficiency in secondary bile salts and rendered them more resistant to C. difficile colitis. Conversely, another study shows how antibiotic administration transiently increases sialic acid levels in the gut, thereby enhancing C. difficile growth.
“Although the mechanisms underlying colonization resistance are complex and remain incompletely defined, there is little doubt that high levels of colonization resistance can be induced by transfer of specific commensal bacteria to vulnerable individuals, and that the degree of colonization resistance—with reductions in colonization density exceeding six orders of magnitude—resembles the degree of resistance induced by some of the most effective vaccines. Thus, from a clinical standpoint, the development of commensal bacteria as preventive and therapeutic agents is a high priority,” writes Dr. Pamer.
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