For a study, it was determined that adults who were not in the hospital were frequently administered antibiotics. Antibiotic-induced changes in the human gut microbiota, on the other hand, were frequently studied in cohorts with prior health problems and/or concomitant treatment, leaving antibiotic effects unclear. To examine the impact of antibiotics on the gut microbiota and, in particular, the gut resistome of a small cohort of healthy adults, the researchers used various omic techniques. Around 3 to 19 species per individual flourished during antibiotic therapy, with Gram-negative bacteria increasing considerably in relative abundance. While the overall number of antibiotic resistance gene homologs did not change significantly, antibiotic-specific gene homologs with possible resistance to the administered antibiotics were present in proliferating species, and their proportion increased dramatically. Furthermore, even 3 months after antibiotic administration, virome sequencing, and plasmid analysis revealed growth of antibiotic-specific resistance gene homologs, whereas paired-end read analysis supported their diffusion among various species. These findings imply that antibiotic therapy can result in a long-term proliferation of antibiotic resistance genes in the human gut microbiota. They added to the growing body of evidence supporting antibiotic stewardship.