Whole-organism Fingerprinting of the Genus Carnobacterium using Fourier Transform Infrared Spectroscopy (FT-IR)

Abstract

In the current study, 67 Carnobacterium and related strains were analysed by FT-IR to evaluate the classification of the strains and to determine the potential of FT-IR with multivariate statistical analyses for Carnobacterium systematics. Materials and Methods Strains and cultivationSixty seven strains (Table 1) were subcultured twice on casein-peptone soymeal-peptone agar (CASO broth (Merck), 1.2% (w/v) Lab M No. 1 agar) for 3 days at 25 °C. Ten strains were examined in duplicate to assess the reproducibility of the system. Effect of culture ageType strains of C. divergens (NCFB 2763 T ), C. gallinarum (MT44 T ), C. mobile (NFCB 2765 T ) and C. piscicola (NCFB 2762 T ) were cultivated on CASO agar for 2, 3, 4 and 5 days at 25 °C. Reproducibility over six monthsThe reproducibility of the method was examined using 15 randomly selected Carnobacterium strains (Table 1). The strains were grown on two occasions separated by a period of six months as previously described on CASO agar at 25 °C for 3 days. Whole-organism Fingerprinting of the Genus SummarySixty seven strains of Carnobacterium, atypical Lactobacillus, Enterococcus durans, Lactobacillus maltaromicus and Vagacoccus salmoninarum were examined by Fourier transform infrared (FT-IR) spectroscopy. The effects of culture age and reproducibility over a six month period were also investigated. The results were analysed by multivariate statistics and compared with those from a previous numerical phenetic study, a pyrolysis mass spectrometry (PyMS) study and with investigations which used DNA-DNA and 16S rRNA sequencing homologies. Taxonomic correlations were observed between the FT-IR data and these studies. Culture age was observed to have little effect on the spectra obtained. The reproducibility study indicated that there was correlation between spectra produced on two occasions over the six month period. It was concluded that FTIR is a reliable method for investigating carnobacterial classification, and may have further potential as a rapid method for use in Carnobacterium identification.

Discrimination of Enterobacterial Repetitive Intergenic Consensus PCR Types of Campylobacter coli and Campylobacter jejuni by Fourier Transform Infrared Spectroscopy

“…The reference work of Helm and colleagues (14) prompted a large amount of research, reviewed by Mariey and colleagues (26). Since 2001, more groups and genera have been studied: Lactobacillus (3,36,37), Carnobacterium (21), Bacillus (1), Brucella (27), Acinetobacter (52), yeasts (20,41), enterococci (7,10,19), coryneforms (24,34), and actinomycetes (54). In all of them, the technique has shown qualities, such as high discriminatory power and reproducibility, allowing the differentiation of taxonomic entities at the species or subspecies level on the basis of changes in the IR absorption patterns of the microbial cell.…”

“…Thus, when applied to intact microbial cells, infrared spectra contain essentially qualitative information about the global biochemical composition of the cells. The interpretation of FT-IR spectra (made up of multiple, complex, overlapped absorbance bands of many different vibrational modes of all the cell components) requires the use of pattern recognition methods, such as hierarchical cluster analysis (HCA) or stepwise discriminant analysis (SDA), to disclose relationships and cluster elements on the basis of their perceived closeness (10,13,21,23,24,36,44,45). SDA can eventually be used to create classification functions able to identify unknowns.…”

Microorganism characterization using ATR–FTIR on an ultrathin polystyrene layer

“…The cells were combined with KBr and pressed to form pellets. The method used by Lai et al (2004) involved drying the sample on an aluminum plate in an oven for 30 min [6]. Spectra were collected by diffuse reflectance-absorbance FTIR.…”

An Overview of the Evolution of Infrared Spectroscopy Applied to Bacterial Typing

“…In 1996, Goodacre [36] proved the ability of diffuse reflectance-absorbance FTIRS and ANN to discriminate nineteen strains of Streptococcus and Enterococcus species. Other works proved the ability of FTIRS combined with chemometrics for Carnobaterium typing, [37] to discriminate species of Actinomycetes, [38] lactic acid bacteria, [39,40] food-borne pathogens commonly found in cheese and milk, [41,42] and pathogens of domestic ruminants and pigs causing mastitis such as Trueperella spp. [19] Regarding Gram-negative bacteria, only Acinetobacter, Burkholderia, and Yersinia genus were explored for species discrimination exclusively within the genus itself.…”

“…Species FTIRS HCA [4,53] Carnobacterium spp. Species FTIRS PCA, UPGMA, ANN [37,40] Lactococcus spp. Species FTIRS HCA, ANN [39,40] Leuconostoc spp.…”