Application of Fourier Transform Infrared Spectroscopy to Discriminate Two Closely Related Bacterial Species: Bacillus anthracis and Bacillus cereus Sensu Stricto

Abstract

Fourier transform infrared spectroscopy (FTIRS) is a diagnostic technique historically used in the microbiological field for the characterization of bacterial strains in relation to the specific composition of their lipid, protein, and polysaccharide components. For each bacterial strain, it is possible to obtain a unique absorption spectrum that represents the fingerprint obtained based on the components of the outer cell membrane. In this study, FTIRS was applied for the first time as an experimental diagnostic tool for the discrimination of two pathogenic species belonging to the Bacillus cereus group, Bacillus anthracis and Bacillus cereus sensu stricto; these are two closely related species that are not so easy to differentiate using classical microbiological methods, representing an innovative technology in the field of animal health.

Perspectives of FTIR as Promising Tool for Pathogen Diagnosis, Sanitary and Welfare Monitoring in Animal Experimentation Models: A Review Based on Pertinent Literature

“…The region of the FTIR spectrum that showed the discrimination of B. anthracis/B. cereus isolates was found to be in the region 1300-700 cm −1 , corresponding to the absorption wave numbers of polysaccharides [40]. Once again, the technique is capable of discriminating pathogens of interest to health; in this case, it was applied to humans but can be extrapolated to animals.…”

A Comprehensive Methodology for Microbial Strain Typing Using Fourier-Transform Infrared Spectroscopy

“…Several studies have shown that FTIR spectroscopy has high discriminatory power, enabling differentiation at the species or subspecies level [ 10 , 22 , 23 ]. It has been successfully employed for strain typing of pathogens such as Legionella pneumophila , Pseudomonas aeruginosa , Streptococcus pneumoniae , Bacillus cereus group, and Staphylococcus aureus [ 21 , 24 , 25 , 26 , 27 ]. A variety of FTIR-based methodologies have been utilized across microbial studies for tasks beyond microbial identification, such as process monitoring, cell wall analysis, biofilm examination, stress response assessment, and investigation of environmental interactions (reviewed by [ 23 , 28 ]).…”