In the News: a Punch to the Gut? Impact of Non-Antibiotic Drugs on Gut Bacteria; and... Coffee Linke

Extensive Impact of Non-Antibiotic Drugs on Human Gut Bacteria

It is known that taking antibiotics can disrupt our gut bacteria (gastrointestinal microbiome) and result in unintended consequences for health and disease. Now, a new study reveals that many non-antibiotic drugs also alter the composition of our gut bacteria in a similar way. In a paper published in the journal Nature, researchers at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, report that not only can many common non-antibiotic drugs alter gut bacteria, but they can also - like antibiotics - contribute to antibiotic resistance.

In their study, the authors mention recent research showing that commonly used non-antibiotic drugs have been associated with changes in gut microbe composition; they also note that the extent of this phenomenon is unknown.

For their investigation, they compiled a panel of 40 species of bacteria that are typically found in the human gut and used it to screen more than 1,000 drugs currently on the market. Of the 923 non-antibiotic drugs that were analyzed, the researchers discovered that 250 had disrupted the growth of at least one of the 40 species of gut bacteria in the panel. They were surprised by the size of their result, especially as the drugs they tested included members of all therapeutic classes.

"This shift in the composition of our gut bacteria contributes to drug side effects," explains study author Peer Bork, who is a professor at EMBL and head of its Structural and Computational Biology Unit.


A few commonly used non-antibiotic drugs have recently been associated with changes in gut microbiome composition, but the extent of this phenomenon is unknown. Here, we screened more than 1,000 marketed drugs against 40 representative gut bacterial strains, and found that 24% of the drugs with human targets, including members of all therapeutic classes, inhibited the growth of at least one strain in vitro. Particular classes, such as the chemically diverse antipsychotics, were overrepresented in this group. The effects of human-targeted drugs on gut bacteria are reflected on their antibiotic-like side effects in humans and are concordant with existing human cohort studies. Susceptibility to antibiotics and human-targeted drugs correlates across bacterial species, suggesting common resistance mechanisms, which we verified for some drugs. The potential risk of non-antibiotics promoting antibiotic resistance warrants further exploration. Our results provide a resource for future research on drug-microbiome interactions, opening new paths for side effect control and drug repurposing, and broadening our view of antibiotic resistance.

Maier, Lisa, Mihaela Pruteanu, Michael Kuhn, Georg Zeller, Anja Telzerow, Exene Erin Anderson, Ana Rita Brochado et al. "Extensive impact of non-antibiotic drugs on human gut bacteria." Nature (2018).

Coffee Linked to Cancer - Acrylamide

North Americans love coffee. More than 3.4 billion pounds of coffee was consumed in the United States between October 2016 and September 2017, more than in the entirety of South America, according to the International Coffee Organization.

Recently, a judge has ruled that coffee sellers in California must warn people that coffee may contain a substance linked to cancer. Judge Elihu M. Berle, in Los Angeles County Superior Court, wrote in a proposed decision that the companies failed to show that acrylamide does not pose a significant risk when produced during roasting. Acrylamide has been identified as a possible cancer-causing substance. The chemical is naturally produced during cooking at high temperatures, including during the roasting of coffee beans.