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Identification of clinical isolates of Aspergillus species from Korean hospitals by using MALDI TOF-MS and molecular sequencing methods
- Date2017-10-12 19:50
- Update2017-10-12 19:57
- DivisionDivision of Strategic Planning for Emerging Infectious Diseases
- Tel043-719-7271
Identification of clinical isolates of Aspergillus species from Korean hospitals by using MALDI TOF-MS and molecular sequencing methods
Kim Il-Hwan, Park Chan*
Division of Antimicrobial Resistance, Center for Infectious Disease Research, KNIH, KCDC
Shin JongHee
Department of Laboratory Medicine, Chonnam National University Medical School, Republic of Korea
Background: Aspergillus species are a leading cause of invasive fungal infections, especially in immunocompromised patients, but their correct identification is challenging. We evaluated matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for the identification of clinical isolates of Aspergillus species, in comparison with sequence-based identification.
Methodology: Clinical isolates of Aspergillus species from 11 hospitals in Korea were identified by gene sequencing of the D1/D2 domain, internal transcribed spacer (ITS), and β-tubulin regions. The identification results between MALDI Biotyper and sequence-based identification were compared.
Results: Sequencing identification of the D1/D2 domain or ITS classified all Aspergillus isolates into six Aspergillus species complexes, and the β-tubulin sequencing method identified several cryptic species. The rates of correct identification of the MALDI Biotyper were 98.6% at the complex level and 88.2% at the species level. Misidentification at the complex level was observed in only 1.4% of cases. Among clinical isolates belonging to 5 cryptic species, only Aspergillus tamarii isolates were identified correctly from the MALDI Biotyper.
Conclusion: The MALDI-TOF MS is highly reliable for identifying clinical isolates of Aspergillus species at the complex level in clinical microbiology laboratories.
Kim Il-Hwan, Park Chan*
Division of Antimicrobial Resistance, Center for Infectious Disease Research, KNIH, KCDC
Shin JongHee
Department of Laboratory Medicine, Chonnam National University Medical School, Republic of Korea
Background: Aspergillus species are a leading cause of invasive fungal infections, especially in immunocompromised patients, but their correct identification is challenging. We evaluated matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for the identification of clinical isolates of Aspergillus species, in comparison with sequence-based identification.
Methodology: Clinical isolates of Aspergillus species from 11 hospitals in Korea were identified by gene sequencing of the D1/D2 domain, internal transcribed spacer (ITS), and β-tubulin regions. The identification results between MALDI Biotyper and sequence-based identification were compared.
Results: Sequencing identification of the D1/D2 domain or ITS classified all Aspergillus isolates into six Aspergillus species complexes, and the β-tubulin sequencing method identified several cryptic species. The rates of correct identification of the MALDI Biotyper were 98.6% at the complex level and 88.2% at the species level. Misidentification at the complex level was observed in only 1.4% of cases. Among clinical isolates belonging to 5 cryptic species, only Aspergillus tamarii isolates were identified correctly from the MALDI Biotyper.
Conclusion: The MALDI-TOF MS is highly reliable for identifying clinical isolates of Aspergillus species at the complex level in clinical microbiology laboratories.
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