Evaluation of MALDI Biotyper and VITEK MS for identifying clinical isolated Streptococcus spp / 中华检验医学杂志

ABSTRACT

Objective Using 16S rRNA gene sequencing as the gold standard method,to compare the performance of two matrix-assisted laser desorption ionization time of flight mass spectrometry system (MALDI Biotyper and VITEK MS) for identifying clinical isolates of Streptococcus spp.Methods One hundred and sixty two clinical Streptococcus isolates were collected at the Second Affiliated Hospital of Zhejiang University,from April to June,2014,and confirmed by 16S rRNA gene sequencing analysis.MALDI Biotyper and VITEK MS mass spectrometry system were used for identification and further evaluated by performance respectively.Results Of all the isolates tested,155 (155/162,95.68％) Streptococcus isolates were accurately identified to species level by MALDI Biotyper.Besides,MALDI Biotyper identified three Streptococcus mitis group as S.pneumoniae and one S.parasanguinis as S.australis.Another three S.pneumonia isolates were not identified accurately (values ＜ 1.7).Although 156 (156/162,96.30％) isolates were accurately identified to species level (including subspecies) by VITEK MS system,two S.pneumoniae as S.mitis/S.oralis and one S.euinus as S.infantarius ssp.infantarius were misidentified.The two systems showed a 100％ (51/51) accuracy in identifying all S.pyogenes and S.agalactiae isolates,and an accuracy higher than 85％ for S.pneumoniae.Conclusions Both systems showed potent identification ability for Streptococcus spp.,VITEK MS system showed more clinical significance in accurately identifying some subspecies.Mass spectrometry system can be used as a rapid identification method for Streptococcs spp.in clinical practice.