Enterococcus species are one of the leading causes of nosocomial infections, which are difficult to treat specially with the rise of its Vancomycin resistant. Studies of Enterococcus isolates are essential for epidemiological investigation. Typing Enterococci is often based on the traditional phenotypic as well as genotypic methods. In this study Fourier-transform infrared (FTIR) spectroscopy is used as a novel phenotypic approach to the typing of Enterococci.

The aim of this work was to establish the feasibility of the combined photoacoustic (PA) and photopyroelectric (PPE) detection of the vapours emitted from essential oils and their corresponding uncrushed leaves or flowers. Gas traces of jasmine (Jessamine (Jasminum)), mint (Mentha arvensis L.) and Damask rose (Rosa damascena Miller) and their essential oils were tested using a combined cell fitted with both a photopyroelectric film (PVDF) and a microphone in conjunction with a pulsed wideband infrared source (PWBS) source. Infrared PA and PPE absorbances were obtained simultaneously at room temperatures with excellent reproducibility and high signal-to-noise ratios. Significant similarities found between the PA and PPE spectra of the trace gas emissions of plant parts, i.e., flowers or leaves and their related essential oils show the good correlation of their emissions and that both effects are initiated by the same absorbing molecules.

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