Prevalence and Genetic Diversity of Toxin Genes in Clinical Isolates of Clostridium perfringens: Coexistence of Alpha-Toxin Variant and Binary Enterotoxin Genes (bec/cpile).

Asami Matsuda,Noriko Urushibara,Masahiko Ito,Satoshi Habadera,Mayumi Nakamura,Mitsuyo Kawaguchiya,Meiji Aung,Nobumichi Kobayashi,Ayako Sumi,Yuka Horino

doi:10.3390/toxins11060326

Asami Matsuda, Noriko Urushibara + Show 8 more

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https://doi.org/10.3390/toxins11060326

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Journal: Toxins	Publication Date: Jun 6, 2019
Citations: 16	License type: CC BY 4.0

Affiliation: Sapporo Medical University, Sapporo Science Center

Abstract

Clostridium perfringens (C. perfringens) is responsible for food-borne gastroenteritis and other infectious diseases, and toxins produced by this bacterium play a key role in pathogenesis. Although various toxins have been described for C. perfringens isolates from humans and animals, prevalence of individual toxins among clinical isolates has not yet been well explored. In the present study, a total of 798 C. perfringens clinical isolates were investigated for prevalence of eight toxin genes and their genetic diversity by PCR, nucleotide sequencing, and phylogenetic analysis. Besides the alpha-toxin gene (plc) present in all the isolates, the most common toxin gene was cpe (enterotoxin) (34.2%), followed by cpb2 (beta2 toxin) (1.4%), netB (NetB) (0.3%), and bec/cpile (binary enterotoxin BEC/CPILE) (0.1%), while beta-, epsilon-, and iota-toxin genes were not detected. Genetic analysis of toxin genes indicated a high level of conservation of plc, cpe, and netB. In contrast, cpb2 was revealed to be considerably divergent, containing at least two lineages. Alpha-toxin among 46 isolates was classified into ten sequence types, among which common types were distinct from those reported for avian isolates. A single isolate with bec/cpile harbored a plc variant containing an insertion of 834-bp sequence, suggesting its putative origin from chickens.

Highlights

Clostridium perfringens (C. perfringens) is a Gram-positive, spore-forming anaerobic bacterium that causes mainly toxic infectious diseases in humans and animals represented by myonecrosis and gastroenteritis [1]
NetB and bec/cpile were identified in two (0.3%) and one (0.1%) isolate from feces, respectively. beta, epsilon, iota-toxin were not detected. cpe was detected in 33.7% of fecal isolates (262/777) and all the isolates from pus, urine, blood, and intestinal mucosa
Prevalence of various toxin genes in C. perfringens was revealed for isolates from clinical specimens, most of which were feces derived from sporadic diarrheal cases

Summary

Introduction

Clostridium perfringens (C. perfringens) is a Gram-positive, spore-forming anaerobic bacterium that causes mainly toxic infectious diseases in humans and animals represented by myonecrosis (gas gangrene) and gastroenteritis [1]. The pathogenicity of this bacterium is associated with extracellular toxins, which include four major toxins (alpha-, beta-, epsilon-, iota-toxin) and enterotoxin. All the C. perfringens isolates produce alpha-toxin, which is implicated in myonecrosis in humans and necrotic enteritis in chickens. C. perfringens enterotoxin (CPE) is an essential factor of human food-poisoning, as well as antibiotic-associated and nosocomial diarrheal diseases [2]. NetB and beta toxins have been described as those associated with necrotic enteritis in chickens and enteric diseases in humans and animals, respectively [5,6]

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