Identification and characterization of Clostridium botulinum group III field strains by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). (December 2017)

• Record Type: Journal Article
• Authors: Bano, Luca; Drigo, Ilenia; Tonon, Elena; Pascoletti, Simone; Puiatti, Cinzia; Anniballi, Fabrizio; Auricchio, Bruna; Lista, Florigio; Montecucco, Cesare; Agnoletti, Fabrizio
• Is Part Of: Anaerobe. Volume 48(2017)
• Page Start: 126
• Page End: 134
• Publication Date: 2017-12
• Subjects: Clostridium botulinum group III -- MALDI-TOF MS -- Animal botulism; Anaerobic infections -- Periodicals; Anaerobic bacteria -- Periodicals; Bacterial diseases -- Periodicals; Computer network resources; Anaerobic protozoa -- Periodicals; 579.3
• DOI: 10.1016/j.anaerobe.2017.08.004
• Languages: English
• ISSNs: 1075-9964

Abstract

Abstract: Animal botulism is primarily due to botulinum neurotoxin (BoNT) types C, D or their chimeric variants C/D or D/C, produced by Clostridium botulinum group III, which appears to include the genetically indistinguishable Clostridium haemolyticum and Clostridium novyi . In the present study, we used matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI TOF MS) to identify and characterize 81 BoNT-producing Clostridia isolated in 47 episodes of animal botulism. The instrument's default database, containing no entries for Clostridium botulinum, permitted reliable identification of 26 strains at the genus level. Although supplementation of the database with reference strains enhanced the instrument's ability to identify the neurotoxic strains at the genus level, resolution was not sufficient to recognize field strains at species level. Characterization by MALDI TOF confirmed the well-documented phenotypic and genetic differences between Clostridium botulinum strains of serotypes normally implicated in human botulism (A, B, E, F) and other Clostridium species able to produce BoNTs type C and D. The chimeric and non-chimeric field strains grouped separately. In particular, very low similarity was found between two non-chimeric type C field strains isolated in the same outbreak and the other field strains. This difference was comparable with the differences among the various Clostridia species included in the study. Characterization by MALDI TOF confirmed that BoNT-producing Clostridia isolated from animals are closely related and indistinguishable at the species level from Clostridium haemolyticum and Clostridium novyi reference strains. On the contrary, there seem to be substantial differences among chimeric and some non-chimeric type C strains. Highlights: MALDI TOF MS has been used to study a remarkable collection of C. botulinum Group III field strains. The botulinum neurotoxin (BoNT) genes have been genetically characterized as chimeric or non-chimeric. MALDI TOF profiling of C. botulinum Group III resulted indistinguishable from C. novyi and C. haemolyticum reference strains. Chimeric strains showed substantial differences from non-chimeric type C strains by MALDI TOF MS. MALDI TOF is a useful tool for the detection of C. botulinum group III, regardless of the presence of the BoNT genes.