Swedish studies link antibiotics to resistance and long-term gut changes

New research from Sweden highlights two distinct ways antibiotics impact biological environments. A study by the University of Gothenburg, published in Nature Communications, found that antibiotics excreted by patients in hospital sewage systems promote the growth of antibiotic-resistant bacteria. Researchers examined hospital and municipal sewage in eight Swedish cities, noting that while municipal treatment plants showed no such effect, hospital sewage systems acted as critical sites for resistance evolution.

Separately, a large-scale study led by Uppsala University and published in Nature Medicine suggests that antibiotic use can leave detectable traces in the gut microbiome for years. By linking national prescription records with stool samples from nearly 15,000 adults, researchers found that certain medicines, such as clindamycin, fluoroquinolones, and flucloxacillin, were associated with differences in gut bacterial diversity even four to eight years after treatment. While these findings do not necessarily imply lasting illness, they indicate that the impact on microbial communities may persist much longer than previously understood.