Identificação e caracterização de bacterias psicrotróficas gram-negativas isoladas de tanque de refrigeração por expansão

Abstract

The aim of this research was to studed the diversity of psychrotrophic Gram-negative microorganisms present in milk in communitarian bulk tank and to evaluate their capacity to production extracellular enzymes and resistance of the isolates to antibiotics. Samples of surfaces of 32 bulk tank milk were collected with sterile swab which that 60 isolates were selected and identified using API 20NE and Bactray kit. Of that isolates 27,6% do not pertain to Enterobacteriaceae and 67,6% pertain to that family. Microorganisms such Aeromonas hydrophila, Pseudomonas fluorescens, Agrobacterium radiobacter, Serratia liquefaciens, Klebsiella ozaenae, Stenotrophomonas maltophilia, Citrobacter freundi, Yersinia kristensenni, Yersinia pseudotuberculosis, Shigella flexineri and Shigela dysinteride were isolated from the bulk tank milk. All microorganisms isolated were evaluated in function of their putative characteristics by production of extra-cellular enzymes, like proteinases, lipases and lecithinases. This research also evaluated the microbial resistance to 10 antibiotic by the test of diffusion in agar. The microorganisms were classified as resistant or susceptible besides their percentage of multiresistance. All of isolated present MAR (Multiple antibiotic resistance) index higher then 40%, meaning resistant to two or more drugs of the ten drogs studied experimented.