Torey Looft

Natural Horizontal Gene Transfer of Antimicrobial Resistance Genes in Campylobacter spp. From Turkeys and Swine

Publisher: Frontiers Media SA

Date: 27-09-2021

DOI: 10.3389/FMICB.2021.732969

Abstract: Antibiotic-resistant C ylobacter constitutes a serious threat to public health. The clonal expansion of resistant strains and/or the horizontal spread of resistance genes to other strains and species can hinder the clinical effectiveness of antibiotics to treat severe c ylobacteriosis. Still, gaps exist in our understanding of the risks of acquisition and spread of antibiotic resistance in C ylobacter . While the in vitro transfer of antimicrobial resistance genes between C ylobacter species via natural transformation has been extensively demonstrated, experimental studies have favored the use of naked DNA to obtain transformants. In this study, we used experimental designs closer to real-world conditions to evaluate the possible transfer of antimicrobial resistance genes between C ylobacter strains of the same or different species ( C ylobacter coli or C ylobacter jejuni ) and originating from different animal hosts (swine or turkeys). This was evaluated in vitro through co-culture experiments and in vivo with dual-strain inoculation of turkeys, followed by whole genome sequencing of parental and newly emerged strains. In vitro , we observed four independent horizontal gene transfer events leading to the acquisition of resistance to beta-lactams ( blaOXA ), aminoglycosides [ aph(2′′)-If and rpsL ] and tetracycline [ tet(O) ]. Observed events involved the displacement of resistance-associated genes by a mutated version, or the acquisition of genomic islands harboring a resistance determinant by homologous recombination we did not detect the transfer of resistance-carrying plasmids even though they were present in some strains. In vivo , we recovered a newly emerged strain with dual-resistance pattern and identified the replacement of an existing non-functional tet(O) by a functional tet(O) in the recipient strain. Whole genome comparisons allowed characterization of the events involved in the horizontal spread of resistance genes between C ylobacter following in vitro co-culture and in vivo dual inoculation. Our study also highlights the potential for antimicrobial resistance transfer across C ylobacter species originating from turkeys and swine, which may have implications for farms hosting both species in close proximity.

A collection of bacterial isolates from the pig intestine reveals functional and taxonomic diversity

Publisher: Springer Science and Business Media LLC

Date: 15-12-2020

DOI: 10.1038/S41467-020-19929-W

Abstract: Our knowledge about the gut microbiota of pigs is still scarce, despite the importance of these animals for biomedical research and agriculture. Here, we present a collection of cultured bacteria from the pig gut, including 110 species across 40 families and nine phyla. We provide taxonomic descriptions for 22 novel species and 16 genera. Meta-analysis of 16S rRNA licon sequence data and metagenome-assembled genomes reveal prevalent and pig-specific species within Lactobacillus , Streptococcus , Clostridium , Desulfovibrio , Enterococcus , Fusobacterium , and several new genera described in this study. Potentially interesting functions discovered in these organisms include a fucosyltransferase encoded in the genome of the novel species Clostridium porci , and prevalent gene clusters for biosynthesis of sactipeptide-like peptides. Many strains deconjugate primary bile acids in in vitro assays, and a Clostridium scindens strain produces secondary bile acids via dehydroxylation. In addition, cells of the novel species Bullifex porci are coccoidal or spherical under the culture conditions tested, in contrast with the usual helical shape of other members of the family Spirochaetaceae . The strain collection, called ‘Pig intestinal bacterial collection’ (PiBAC), is publicly available at www.dsmz.de ibac and opens new avenues for functional studies of the pig gut microbiota.

Bowling Green State University

Location: United States of America

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USDA-ARS National Animal Disease Center

Location: United States of America

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USDA Agricultural Research Service

Location: United States of America

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Iowa State University

Location: United States of America

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