Uncertainties in Identification of Elizabethkingia meningoseptica

Abstract

To the Editors: With reference to the article entitled “Isolation of Methicillin Resistant Staphylococcus aureus and Multidrug Resistant Elizabethkingia meningoseptica From Neonates Within Minutes of Birth” by Kwambana-Adams et al,1 we would like to comment on the automated API (Analytical Profile Index) system (BioMerieux, Basingstoke, United Kingdom), used by the authors for identification of bacterial isolates including E. meningoseptica. According to a recent study by Lin et al,2 where they compared 4 automated systems with 16S rRNA gene sequencing for identification of Elizabethkingia species, overall correct rate for identification was 24.5% for API/ID 32 v3.1system. Although API system identified 12 of 13 E. meningoseptica isolates, all other Elizabethkingia species such as Elizabethkingia anophelis and Elizabethkingia miricola were also misidentified as E. meningoseptica because of absence of database coverage for these species. Moreover, an isolate of Chryseobacterium species was also misidentified as E. meningoseptica by the automated system. These data add to the identification inaccuracies of the API system with regard to Elizabethkingia species. To the best of our efforts, we could not find any other study which used API system for the identification of this organism. Even the review article3 cited by Kwambana-Adams et al1 did not mention the identification methods for Elizabethkingia species. Correct identification of the organism is crucial for the diagnosis and management strategies as E. anophelis has also recently emerged as a nosocomial neonatal pathogen.4 Hence, differentiation between E. anophelis and E. meningoseptica requires accurate microbial identification. MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionization-Time Of Flight Mass Spectrometry) is a valuable tool for diagnosis of such unusual pathogens. However, more comparative studies are required with expanded databases of MALDI-TOF MS with species-specific spectra for reliable diagnosis of this pathogen. Also, we recommend database updation of API system for Elizabethkingia species other than E. meningoseptica. Gurmeet R. Rahim, PhDNeha Gupta, MDDepartment of MicrobiologyShah SatnamJi Speciality HospitalsSirsa, Haryana, India[email protected]