Proteomics for Botulism Outbreak Investigations: a Powerful Tool to Track Sources of Intoxication and Commonality of Botulism Outbreaks

摘要

Botulinum neurotoxin (BoNT) is considered a likely agent for bioterrorism due to its high availability, ease of use, and high toxicity. BoNT is produced by some Clostridia species of bacteria and it consists of seven serotypes, A-G. All BoNTs cleave proteins necessary for nerve transmission, resulting in flaccid paralysis. Epidemiological and laboratory investigation can halt an outbreak of botulism through identification of the source of the contamination. However, some BoNTs are extremely similar in amino acid sequence, making identification of commonalities in BoNT obtained from different samples a difficult task. We have developed a proteomics method to obtain amino acid sequence information on the toxin through enzymatic digest of the toxin followed by online HPLC separation and tandem mass spectrometry. Thousands of MS/MS spectra are obtained in a typical proteomics experiment and the data are largely interpreted with the aid of database searching with some de novo sequencing tools. Through the use of these tools, we can determine the amino acid sequence of the toxin, aiding in epidemiologic or forensic investigations. We present here the results of identification of the toxin from several different botulism outbreaks, some of which can bedifferentiated from other proteins with 99.9% amino acid sequence identity.