Rapid detection and surveillance of cfiA-positive Bacteroides fragilis using matrix-assisted laser desorption ionization time-of-flight mass spectrometry

• Published in: Anaerobe Vol. 72; p. 102448
• Main Authors: Kawamoto, Yasuhide, Kosai, Kosuke, Ota, Kenji, Uno, Naoki, Sakamoto, Kei, Hasegawa, Hiroo, Izumikawa, Koichi, Mukae, Hiroshi, Yanagihara, Katsunori
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2021
• Subjects: Anti-Bacterial Agents - pharmacology; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacterial Typing Techniques; Bacteroides fragilis - classification; Bacteroides fragilis - drug effects; Bacteroides fragilis - genetics; Bacteroides fragilis - isolation & purification; Bacteroides Infections - diagnosis; Bacteroides Infections - microbiology; beta-Lactamases - genetics; beta-Lactamases - metabolism; Carbapenem resistance; Disease Management; Humans; MALDI-TOF MS; Meropenem hydrolysis; Metallo-β-lactamase; Microbial Sensitivity Tests; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Meropenem hydrolysis; MALDI-TOF MS; Metallo-β-lactamase; Carbapenem resistance
• ISSN: 1075-9964; 1095-8274
• DOI: 10.1016/j.anaerobe.2021.102448

To perform surveillance of cfiA-positive Bacteroides fragilis using new subtyping software module, MALDI Biotyper Subtyping Module (MBT Subtyping Module), on MALDI-TOF MS system, and to evaluate the detection ability of the module. cfiA-positive strains were presumed using the module against B. fragilis isolated between 2006 and 2019. The cfiA gene was confirmed using PCR. In cfiA-positive B. fragilis, the insertion sequence (IS) elements were examined and the MBT STAR-BL assay was performed to examine meropenem hydrolysis activity. Of the 396 B. fragilis strains included, the MBT Subtyping Module detected 33 presumptive cfiA-positive strains (8.3%), of which 32 harbored the cfiA gene. The sensitivity and specificity of the MBT Subtyping Module for detecting cfiA-positive B. fragilis were 100.0% and 99.7%, respectively. Of the 32 strains harboring the cfiA gene, seven strains possessed IS elements, which were thought to induce high cfiA expression. Meropenem hydrolysis was detected in all seven strains that were positive for both cfiA and IS elements, and they exhibited resistance to meropenem and imipenem. The overall non-susceptibility rates to meropenem and imipenem were 84.8% and 36.4%, respectively, in the 33 presumptive cfiA-positive strains. The MBT Subtyping Module can detect cfiA-positive B. fragilis rapidly and accurately, supporting its use for surveillance of cfiA-positive B. fragilis in clinical settings. •The MBT Subtyping Module detected cfiA-positive B. fragilis on the MALDI-TOF MS system.•The rate of cfiA-positive B. fragilis was higher than carbapenem resistance rates.•The cfiA-positive B. fragilis exhibited decreased carbapenem susceptibility.