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PubMed2026

Potential dissemination and persistence of Clostridium perfringens along the slaughtering process in French cattle, pig or poultry slaughterhouses.

Clostridium perfringens is a major foodborne pathogen associated with meat products, yet its dissemination routes and persistence within slaughterhouses remain poorly understood. In this study, whole-genome sequencing combined with multilocus sequence typing (MLST), core genome MLST (cgMLST), and core single nucleotide polymorphism (SNP) analysis was applied to 286 C. perfringens isolates collected from cattle, pig, and poultry slaughterhouses in France. MLST analysis revealed extensive genetic diversity, with most isolates assigned to novel allelic profiles rather than previously described sequence types. Phylogenetic analyses based on cgMLST and SNP data revealed frequent recovery of closely related isolates from feces, meat, surfaces, and air, highlighting widespread dissemination of strains within slaughterhouses during processing. Notably, close genetic related isolates recovered from air and other sample types are consistent with air-associated dissemination within slaughterhouse environments. In addition, the detection of closely related strains across different sampling campaigns suggests the potential persistence of C. perfringens within slaughterhouse environments over time. Most isolates were classified as toxinotype A (97.9%), with a few belonging to toxinotypes D (1.0%) and G (1.0%), and in silico analyses revealed a broad distribution of virulence-associated genes. Antimicrobial resistance genes (ARGs) were commonly detected, particularly those conferring resistance to tetracyclines, although isolates carrying multiple ARGs remained infrequent. Overall, this study provides new insights into the genomic diversity, dissemination pathways, and persistence of C. perfringens in multi-species slaughterhouses. These findings highlight the potential role of air-associated dissemination in contamination dynamics and underscore the importance of improved hygiene control strategies to mitigate food safety risks along the meat production chain.

Antimicrobial resistance gene (ARG)↗
PubMed1986

Structural analysis of type II variants within the mouse intracisternal A-particle sequence family.

Intracisternal A-particle (IAP) elements are present in multiple copies in the mouse and other rodent genomes. The bulk of this sequence family in Mus musculus consists of 7 Kb long elements, but the majority of IAP sequences involved in known transpositions have been deleted forms. The present study describes a subset of deleted IAP sequences (type II IAP) characterized by insertion of a particular short sequence element (AIIins). AIIins are interspersed and the majority occur as part of the type II IAP elements in the mouse genome. AIIins sequences are absent or in low copy number outside Mus musculus. We have isolated clones containing AIIins from a mouse genomic DNA library and have sequenced three isolates of AIIins and their surrounding IAP sequences to define the detailed structure of type II elements. AIIins are 272, 268 and 264 bp long and 90% homologous in sequence. They are bracketed by 9 bp duplications, suggesting they may be inserted elements. A 75 bp region containing a core enhancer sequence is repeated at the 5' end in type II IAP elements. Insertion into the IAP genome, with potential to encode an integrase function, may have played a role in the amplification of AIIins.

Animals↗
PubMed1990

Botulinum neurotoxin type A: sequence of amino acids at the N-terminus and around the nicking site.

Clostridium botulinum synthesizes the type A botulinum neurotoxin (NT) as a approximately 150 kDa single chain protein. Post-translational proteolytic processing yields a approximately 150 kDa dichain protein composed of a approximately 50 kDa light and approximately 100 kDa heavy chain, which has higher toxicity. Trypsin's action mimics the endogenous proteolytic processing. The proteolytic cleavages could occur at 4 sites. We have examined 2 such sites and defined the peptide sequences before and after proteolytic processing. The N-terminal residues of the newly synthesized approximately 150 kDa single chain NT, Pro-Phe-Val-Asn-Lys-, remain intact at the N-terminus of the approximately 50 kDa light chain generated either in the clostridial culture or in vitro with trypsin or with a protease purified from the homologous bacterial culture. The clostridial protease cleaves the single chain NT in vitro, at 1/3 the distance from its N-terminus, on the amino side of Gly of the sequence -Gly-Tyr-Asn-Lys-Ala-Leu-Asn-Asp-Leu- before cleaving the bond Lys-Ala at a slower rate. The data indicate that the dichain NT is formed in the bacterial culture in at least 2 steps. Cleavage at X-Gly produces a approximately 100 kDa heavy chain-like fragment which is then truncated; cleavage 4 residues downstream at Lys-Ala, and excision of the tetrapeptide Gly-Tyr-Asn-Lys, generates the mature heavy chain with Ala as its N-terminal residue. The approximately 100 kDa heavy chain generated in vitro, by nicking the single chain NT with trypsin, also has Ala-Leu-Asn- as the N-terminal residues.

Amino Acid Sequence↗