Work

Evaluation of Live Bacterial Prophylactics to Decrease IncF Plasmid Transfer and Association With Intestinal Small RNAs

Year: 2021

Type: article

Abstract: Chicken intestinalEscherichia coliare a reservoir for virulence and antimicrobial resistance (AMR) genes that are often carried on incompatibility group F (IncF) plasmids. The rapid transfer of these plasmids between bacteria in the gut contributes to the emergence of new multidrug-resistant and virulent bacteria that threaten animal agriculture and human health. Thus, the aim of the present study was to determine whether live bacterial prophylactics could affect the distribution of large virulence plasmids and AMR in the intestinal tract and the potential role of smRNA in this process. In this study, we tested ∼100 randomly selectedE. colifrom pullet feces (n= 3 per group) given no treatment (CON), probiotics (PRO), a liveSalmonellavaccine (VAX), or both (P + V).E. coliisolates were evaluated via plasmid profiles and several phenotypic (siderophore production and AMR), and genotypic (PCR for virulence genes and plasmid typing) screens. P + V isolates exhibited markedly attenuated siderophore production, lack of AMR and virulence genes, which are all related to the loss of IncF and ColV plasmids (P< 0.0001). To identify a causal mechanism, we evaluated smRNA levels in the ceca mucus and found a positive association between smRNA concentrations and plasmid content, with both being significantly reduced in P + V birds compared to other groups (P< 0.01). To test this positive association between IncF plasmid transfer and host smRNA concentration, we evenly pooled smRNA per group and treatedE. colimating pairs with serial concentrations of smRNAin vitro. Higher smRNA concentrations resulted in greater rates of IncF plasmid transfer betweenE. colidonors (APEC O2 or VAX isolate IA-EC-001) and recipient (HS-4) (all groups;P< 0.05). Finally, RNAHybrid predictive analyses detected several chicken miRNAs that hybridize with pilus assembly and plasmid transfer genes on the IncF plasmid pAPEC-O2-R. Overall, we demonstrated P + V treatment reduced smRNA levels in the chicken ceca, which was associated with a reduction in potentially virulentE. coli. Furthermore, we propose a novel mechanism in which intestinal smRNAs signal plasmid exchange betweenE. coli. Investigations to understand the changes in bacterial gene expression as well as smRNAs responsible for this phenomenon are currently underway.

Source: Frontiers in Microbiology

DOI: 10.3389/fmicb.2020.625286

Authors: Graham A. J. Redweik, Mary Kate Horak, Ryley Hoven, Logan Ott, Melha Mellata

Institution: Iowa State University

Language: English

Topic: Escherichia coli research studies

Subfield: Endocrinology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDGs: Good health and well-being, Zero hunger

Open Access status: gold

Estimated APC paid: $2,950