Preventive antibiotic treatment of calves: emergence of dysbiosis causing propagation of obese state‐associated and mobile multidrug resistance‐carrying bacteria

Abstract

Summary In agriculture, antibiotics are used for the treatment and prevention of livestock disease. Antibiotics perturb the bacterial gut composition but the extent of these changes and potential consequences for animal and human health is still debated. Six calves were housed in a controlled environment. Three animals received an injection of the antibiotic florfenicol (Nuflor), and three received no treatment. Faecal samples were collected at 0, 3 and 7 days, and bacterial communities were profiled to assess the impact of a therapy on the gut microbiota. Phylogenetic analysis (16S‐rDNA) established that at day 7, antibiotic‐treated microbiota showed a 10‐fold increase in facultative anaerobic Escherichia spp, a signature of imbalanced microbiota, dysbiosis. The antibiotic resistome showed a high background of antibiotic resistance genes, which did not significantly change in response to florfenicol. However, the maintenance of Escherichia coli plasmid‐encoded quinolone, oqxB and propagation of mcr‐2, and colistin resistance genes were observed and confirmed by Sanger sequencing. The microbiota of treated animals was enriched with energy harvesting bacteria, common to obese microbial communities. We propose that antibiotic treatment of healthy animals leads to unbalanced, disease‐ and obese‐related microbiota that promotes growth of E. coli carrying resistance genes on mobile elements, potentially increasing the risk of transmission of antibiotic resistant bacteria to humans.

Preventive Antibiotic Treatment Increases Neonatal Chicks Susceptibility to Salmonella Infection Via Disrupting Gut Microbiota and Linoleic Acid Metabolism

“…Furthermore, the Salmonella infection after FFC pre-treated chicks had the had the highest relative abundance of Proteobacteria, which was known to be the potential pathogens of poultry and/or humans. The recent study showed that the orfenicol preventive treatment of calves showed a 10-fold increase in facultative anaerobic Escherichia spp, which a signature of imbalanced microbiota [78]. And Sáenz et al oral administration of orfenicol to the sh observed a shift in the gut microbiome towards well-known putative pathogens such as Salmonella, Plesiomonas, and Citrobacter [79].…”

Preventive Antibiotic Treatment Increases Susceptibility of Neonatal chicks to Salmonella Infection via Disrupting Gut Microbiota and Linoleic Acid Metabolis

“…Furthermore, Salmonella infection after FFC pre-treatment chicks had the highest relative abundance of Proteobacteria, which is known to be potential pathogens of poultry and humans. A recent study showed that preventive treatment of calves with orfenicol resulted in a 10-fold increase in facultative anaerobic Escherichia spp, which is a signature of imbalanced microbiota [78]. Sáenz et al reported that oral administration of orfenicol to sh resulted in a shift in the gut microbiome towards well-known putative pathogens such as Salmonella, Plesiomonas, and Citrobacter [79].…”

Fighting the enemy: one health approach against microbial resistance

“…One of these consequences is a disproportional increase in the abundance of specific bacteria that may carry mobile elements containing ARGs. The study by Dobrzanska and colleagues (2020) in Microbial Biotechnology correlates changes in gut microbiota composition, after preventive antibiotic therapy, with weight gain and disease in calves. In this work, calves treated with Florfenicol changed their gut microbiota composition with enrichment of a facultative anaerobe Proteobacteria (mainly E. coli ) and consequently of E. coli mobile‐mediated ARGs that provided resistance to other drugs not administered to the calves.…”

“…Antibiotic treated calves also showed an increase in body weight compared to the non‐treated group, although both groups followed the same diet. Authors propose that antibiotic treatment of healthy animals led to unbalanced, disease‐ and obese‐related microbiota, that promotes the growth of microorganisms carrying clinically relevant mobile ARGs, and potentially increasing the risk of transmission of antibiotic‐resistant bacteria to humans (Dobrzanska et al , 2020).…”

“…Authors propose that antibiotic treatment of healthy animals led to unbalanced, disease-and obeserelated microbiota, that promotes the growth of microorganisms carrying clinically relevant mobile ARGs, and potentially increasing the risk of transmission of This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. antibiotic-resistant bacteria to humans (Dobrzanska et al, 2020).…”