Researchers from Helmholtz Zentrum München, the University of Copenhagen, and the University of Campinas in Brazil have uncovered new insights into the mechanisms behind the transfer of antibiotic resistance genes among bacteria. Published in the journal Microbiome, the study challenges previous assumptions by revealing a more diverse range of mechanisms than previously understood.
Prof. Dr. Michael Schloter, head of the Research Unit for Comparative Microbiome Analyses at Helmholtz Zentrum München, emphasizes the alarming increase in antibiotic-resistant microorganisms due to the extensive use of antibiotics in human and veterinary medicine over the past 70 years. The study aims to understand the mechanisms responsible for the development of antibiotic resistance, particularly the concerning trend where microorganisms become resistant to multiple antibiotics.
The researchers focused on fish raised in aquaculture, specifically the South American pacu species (Piaractus mesopotamicus), and administered the antibiotic florfenicol in their food for 34 days. The study revealed an expected increase in genes responsible for resistance to the antibiotic, including those for pump proteins that remove the active substance from bacteria. However, the researchers were surprised to discover various mechanisms facilitating the spread of antibiotic resistance genes among gut bacteria in the fish.
Johan Sebastian Sáenz Medina, lead author of the paper, explains that the study identified the transfer of resistance genes through viruses (phages) and transposons, challenging the previous notion that only plasmids played a significant role in such gene exchange. Metagenomic studies further confirmed the rapid distribution of resistance genes among different organisms.
The findings prompt a re-evaluation of existing dissemination models and raise questions about the continued use of antibiotics in aquacultures globally. The researchers emphasize the need for modified approaches to antibiotic use, considering the diverse mechanisms uncovered in this study.
Source: Helmholtz Zentrum München