Beyond the plate: Genomic characterization of an extensive school Clostridium perfringens type F outbreak.

Abstract

Objectives: Clostridium perfringens is one of the leading causes of food-borne outbreaks (FBO). This study explores the epidemiological and genomic features of a major FBO occurred in a Spanish school in 2023. Methods: Through genomic analysis, the virulence factors and relatedness of C. perfringens strains involved in a widespread gastroenteritis outbreak were identified RESULTS: The FBO had a unimodal epidemic curve, affecting 526 people. The likely source was the meat in Bolognese sauce. The clinical strains, which belonged to two different clonal lineages (ST-804/cgST-804 and ST5/cgST-801), carried a wide virulence profile with multiple toxins including CPA, enterotoxin CPE, cytolytic toxin CPB2, perfringolysin, collagenase A, clostripain, hyaluronidases (NagHIJKL) and sialidases (NanIHJ). FBO strains of C. perfringens type F carry the cpe gene on the chromosome rather than on a plasmid. However, during this outbreak, the cpe gene, encoding the CPE enterotoxin, was mobilized by a pCPF4969-like plasmid. Susceptibility to metronidazole and vancomycin was retained. Distinct phage repertoires were observed in both lineages. Conclusions: This is the first genomic study of a C. perfringens FBO in Spain, suggesting a multiple contamination sources in the same outbreak. The findings underscore substantial public health concerns related to food safety practices within large-scale user facilities.