Fourier Transform Infrared Spectroscopy Typing an Enterococcus sp.

Abstract

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. FTIR spectroscopy results compared to antibiotic susceptibility testing and PCR amplification of Vancomycin gene results; the analysis showed that, 6 isolates were positive for Van gene (4 of VanA, 1 of VanB and 1 VanA plus VanB). Three of VanA and VanA plus VanB were resistant to all antibiotic tested (Ampicillin, Teicoplamin and Vancomycin) and VanB was found to be sensitive. FTIR spectroscopy (first derivatives) divided the isolates into 8 groups. 3 groups of VanA (4 isolates), one of VanB (one isolate), one of VanA plus VanB (one isolate) and the other 13 Enterococcus isolates were divided into 3 clusters. The study demonstrated that FTIR spectroscopy has good discriminative capacity and high reproducibility as compared to other techniques.