Application of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry to Screen the Extended-Spectrum β-Lactamase-Producing ST131 Escherichia coli Strains.
- Author:
Young Ah KIM
1
;
Dongeun YONG
;
Yong Ha IN
;
Hyung Soon PARK
;
Kyungwon LEE
Author Information
- Publication Type:Original Article
- Keywords: Escherichia coli; Extended-spectrum β-lactamase; Matrix-assisted laser desorption ionization time-of-flight mass spectrometry; Sequence type 131; Serogroup O16; Serogroup O25b
- MeSH: Bacteria; Clone Cells; Escherichia coli*; Escherichia*; Mass Screening; Mass Spectrometry*; Methods; Pandemics; Sensitivity and Specificity; Serogroup
- From:Annals of Clinical Microbiology 2016;19(3):65-69
- CountryRepublic of Korea
- Language:Korean
- Abstract: BACKGROUND: Sequence type 131 (ST131) O25b serogroup Escherichia coli, producing CTX-M type extended-spectrum β-lactamase (ESBL), is a major clone involved in worldwide pandemic spread in both community- and healthcare-associated infections. Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has become a routine tool for the identification of bacteria in many laboratories. This study aimed to assess the performance of MALDI-TOF MS for the screening of ESBL-producing E. coli ST131 in a rapid, inexpensive, and simple way. METHODS: A total 26 clinical E. coli, isolated from blood between 2013 and 2014, were used. The characteristics are ST131-O25b ESBL producers (n=6), ST131-O16 ESBL producers (n=4), non-ST131 ESBL producers (n=11), and non-ST131 non-ESBL producers (n=5). Specific biomarker peaks to distinguish the ST131 clonal group from others were investigated by MicroIDSys (ASTA, South Korea) and ASTA Tinkerbell 2.0 software. RESULTS: A peak at 9,713 m/z peak is useful to screen for ST131 E. coli, regardless of serogroup O25 or O16, showing a sensitivity of 100%, specificity of 56.2%, positive predictive value of 58.8%, and negative predictive value of 100% when using a relative intensity cutoff of 15%. CONCLUSION: We can screen for ST131 E. coli using MicroIDSys (ASTA), MALDI-TOF MS in a rapid, inexpensive, and simple way. However, other confirmatory tests are needed to confirm ST131 E. coli due to the low specificity of this method.
