Brucella Melitensis Misidentified As Roseomonas Gilardii By Maldi-Tof Ms: Experience Of A Clinical Microbiology Laboratory

Abstract

Misidentification of a blood culture isolate of Brucella melitensis as Roseomonas gilardii by the VITEK (R) MS (bioMerieux, Marcy l'Etoile, France) matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) microbial identification system is herein drawn attention. Blood and serum samples of a 42-year-old male with pre-diagnosed neurobrucellosis were evaluated in bacteriology and serology laboratories. Gram-negative coccobacilli from positive blood culture bottle were identified as R. gilardii by VITEK (R) MS, but it was not identified by VITEK (R) 2 Compact (bioMerieux, Marcy l'Etoile, France) MALDI-TOF MS microbial identification system. Serological tests were positive for brucellosis, so it was an important clue for the possibility of a misidentification. The isolated organism was confirmed as B. melitensis by polymerase chain reaction and biotyping in the National Reference Laboratory. Microbiology laboratories in countries where brucellosis is endemic must be careful while using commercial bacterial identification systems for identification of Brucella spp.