Identificação de Salmonella spp. por espectroscopia de fluorescência

Abstract

Salmonella are the main etiological agents of DTAs in the world, responsible for millions of diarrheal diseases and thousands of deaths per year. Despite being a widely known species, the process for confirming it as the cause of ATD is slow and of high economic cost. In order to confirm the diagnosis, the micro-organism is isolated in a culture medium and biochemical characterization test, however these procedures take 15 days according to the rules established by Anvisa. Understanding the importance of reducing the response time of conventional methods, salmonella isolates were evaluated in a spectrofluorimeter. The strains of Salmonella Enteritidis and Salmonella Minnesota were inoculated on several agars (Salmonella-Shigella Agar, Hektoen Enteric, Macconkey, and Three Sugars and Iron); after the inoculation period, their colonies were diluted in 0.9% saline solution and, to obtain their emission spectra, they were analyzed in the spectrofluorimeter with wavelength excitation at 280 nm, covering the 200 wavelength spectral region at 700 nm. With the acquisition of spectra, it was concluded that Hektoen's Enteric Agar has better performance for the analysis. Still, it was found that there is a difference in the emission wavelength of serotypes, in which Salmonella Enteritidis presented λem/max = 336 nm and the strains of Salmonella Minnesota presented λem/max = 332 nm.