Evaluation of the automated system Vitek2 for identification and antimicrobial susceptibility testing of Brazilian Gram-positive cocci strains

Autor: Pedro Alves d'Azevedo, Itacy Siquiera, Juliana Gugel, Ana Lúcia Souza Antunes, Carina Secchi, Jacyr Pasternak, Marinês Dalla Vale Martino
Jazyk: angličtina
Předmět:
Zdroj: Brazilian Journal of Infectious Diseases, Vol 13, Iss 2, Pp 107-110
Druh dokumentu: article
ISSN: 1678-4391
1413-8670
DOI: 10.1590/S1413-86702009000200007
Popis: Automated instruments offer many advantages for clinical laboratories. Nevertheless, they can have problems identifying and determining susceptibilities of some pathogens. Vitek® 2 (bioMérieux) is an automated system that was recently introduced to Brazil. We evaluated the performance of this equipment for Brazilian isolates that had been characterized using reference identification and antimicrobial susceptibility testing methods. Ninety-nine strains of Gram-positive cocci from a local reference center collection were analyzed, consisting of 50 coagulasenegative Staphylococcus (CoNS) and 49 Enterococcus and related species. Vitek® 2 correctly identified 79.8% (79/99) of the isolates. Oxacillin resistance was detected in 76% (19/25) of resistant S. epidermidis strains and in 88% (22/25) of other resistant CoNS species strains. Vancomycin resistance was detected in 100% (20/20) of resistant Enterococcus and related species strains. Vitek® 2 performed very well for the identification of S. epidermidis and non-epidermidis staphylococci, and for the detection of vancomycin resistance in Enterococcus and related species. However, the system needs improvement in order to provide reliable results for the characterization of some CoNS species, identification of Enterococcus and related species and for detecting oxacillin resistance in CoNS.
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