Novel Putative Transposable Element Associated with the Subtype E5 Botulinum Toxin Gene Cluster of Neurotoxigenic Clostridium butyricum Type E Strains from China.

Tao Li,Giovanna Franciosa,Hui Wang,Angelo Iacobino,Liangyan Zhang,Nianzhi Ning

doi:10.3390/ijms23020906

Tao Li, Giovanna Franciosa + Show 4 more

Open Access

https://doi.org/10.3390/ijms23020906

Copy DOI

Abstract

Previously, a whole-genome comparison of three Clostridium butyricum type E strains from Italy and the United States with different C. botulinum type E strains indicated that the bont/e gene might be transferred between the two clostridia species through transposition. However, transposable elements (TEs) have never been identified close to the bont/e gene. Herein, we report the whole genome sequences for four neurotoxigenic C. butyricum type E strains that originated in China. An analysis of the obtained genome sequences revealed the presence of a novel putative TE upstream of the bont/e gene in the genome of all four strains. Two strains of environmental origin possessed an additional copy of the putative TE in their megaplasmid. Similar putative TEs were found in the megaplasmids and, less frequently, in the chromosomes of several C. butyricum strains, of which two were neurotoxigenic C. butyricum type E strains, and in the chromosome of a single C. botulinum type E strain. We speculate that the putative TE might potentially transpose the bont/e gene at the intracellular and inter-cellular levels. However, the occasional TE occurrence in the clostridia genomes might reflect rare transposition events.

Highlights

Botulism is a disease that affects humans, other mammals, birds and fish
The four neurotoxigenic C. butyricum type E strains from China that were sequenced in this study are among the rare botulinum neurotoxin (BoNT)-producing strains belonging to species other than C
Together with the neurotoxigenic C. butyricum type E strains isolated to date in

Summary

Introduction

Botulism is a disease that affects humans, other mammals, birds and fish. It results from the blockade of neurotransmitter release at the peripheral junctions by the botulinum neurotoxin (BoNT). Of the nine distinct BoNT serotypes that have been identified so far (BoNT/A through H and BoNT/X), BoNT/E is among those that more frequently cause botulism in humans [1]. BoNT/E can be produced by the Clostridium botulinum strains of phylogenetic Group. II and atypical strains of neurotoxigenic C. butyricum (phylogenetic Group VI). Clostridia phylogenetic Groups (I through VI) can be considered separate species [2,3]. In Italy, where neurotoxigenic C. butyricum type E strains were originally isolated, those microorganisms have been involved in type E botulism more frequently than C

Objectives

Methods

Results

Conclusion