No 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.

R E . 1995. Forty-eight strains of Carnobacterium were examined by pyrolysis mass spectrometry (PyMS). T h e effects of culture age and reproducibility over a 4 week period were also examined. T h e results were analysed by multivariate statistical techniques and compared with those from a previous numerical taxonomic study based on morphological, physiological and biochemical characteristics and with studies which used DNA-DNA and 16s rRNA sequence homologies. Taxonomic correlations were observed between the PyMS data and the previous studies. Culture age was observed to have little effect on the mass spectra obtained and the reproducibility study indicated that there was very little variation over the 4 week period. It was concluded that PyMS provides a reliable method for studying carnobacterial classification and provides a rapid way for clarifying and refining subgeneric relationships within the genus Carnobacterium. Further work may also show that it offers a potentially very rapid and accurate method for the identification of Carnobacterium.

The potential of the randomly amplified polymorphic DNA polymerase chain reaction (RAPD‐PCR) technique to differentiate Carnobacterium divergens from other members of the genus Carnobacterium was examined. A numerical analysis of the genomic profiles obtained demonstrated that it was possible to differentiate the C. divergens strains from other Carnobacterium strains using this technique. The heterogeneity observed in the representatives of the species C. piscicola adds further weight to the suggestion in other taxonomic studies that subspecies of this species exist.