Department of Infection Control and Prevention, The University of Tokyo Hospital, Tokyo, Japan.
Department of Infectious Diseases, The University of Tokyo Hospital, Tokyo, Japan.
Microbiol Spectr. 2022 Oct 26;10(5):e0284422. doi: 10.1128/spectrum.02844-22. Epub 2022 Sep 20.
Klebsiella variicola is a pathogen that is increasingly recognized as being associated with human infections, but the methods available to clinical microbiology laboratories for accurate identification are limited. In this study, we assessed the accuracy of identification of by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry using genetic identification with multiplex PCR as the reference method. Antimicrobial susceptibilities and virulence of strains were also investigated. Fifty-five Klebsiella pneumoniae, 26 , and 2 Klebsiella quasipneumoniae clinical strains were used for evaluation. Both MALDI Biotyper with library version 9 and Klebsiella MALDI TypeR, a web-based species identification tool using MALDI-TOF data, accurately identified all strains. In addition, two strains of were accurately identified with Klebsiella MALDI TypeR. Whole-genome sequencing confirmed the accurate identification to the subspecies level by Klebsiella MALDI TypeR for four strains (two strains each of subsp. and subsp. ). While 13 strains, 3 strains, and 1 strain of K. pneumoniae showed nonsusceptibility to ampicillin-sulbactam, ceftriaxone, and meropenem, respectively, all strains of were susceptible to all tested antimicrobial agents. Although two strains were positive for the string test, no strains harbored any of the genes associated with hypervirulence of K. pneumoniae. Accurate identification of the K. pneumoniae complex, including , by MALDI-TOF in clinical microbiology laboratories is expected to clarify the clinical characteristics of each species in the future. Recent widespread use of bacterial whole-genome sequencing analysis has resulted in the proposal of novel bacterial species and reclassification of taxonomy. Accurate methods for identification of bacterial species in clinical microbiology laboratories are essential to accumulate information on the clinical characteristics of each bacterial species. Klebsiella variicola is a member of the Klebsiella pneumoniae complex, and its association with human infections has been increasingly recognized, but accurate identification methods approved for use in clinical microbiology laboratories have been limited thus far. The findings of the present study suggest that can be accurately identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry using updated library or web-based identification tools. Accurate identification will promote exploration of clinical characteristics of .
洋葱伯克霍尔德菌是一种日益被认为与人类感染有关的病原体，但临床微生物学实验室可用于准确鉴定的方法有限。在这项研究中，我们评估了基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱法通过多重 PCR 进行基因鉴定的准确性，将其作为参考方法。还研究了 菌株的药敏性和毒力。使用 55 株肺炎克雷伯菌、26 株洋葱伯克霍尔德菌和 2 株产酸克雷伯菌临床株进行评估。MALDI Biotyper 带有版本 9 的文库和基于 MALDI-TOF 数据的网络物种鉴定工具 Klebsiella MALDI TypeR 均准确鉴定了所有 菌株。此外，Klebsiella MALDI TypeR 还准确鉴定了 2 株洋葱伯克霍尔德菌。全基因组测序证实，Klebsiella MALDI TypeR 对 4 株菌（各 2 株）亚种和亚种的亚属水平的准确鉴定。虽然 13 株肺炎克雷伯菌、3 株洋葱伯克霍尔德菌和 1 株产酸克雷伯菌对氨苄西林-舒巴坦、头孢曲松和美罗培南分别表现出耐药性，但所有 菌株均对所有测试的抗菌药物敏感。虽然 2 株洋葱伯克霍尔德菌的串珠试验阳性，但没有 株菌携带与肺炎克雷伯菌高毒力相关的任何基因。预计在未来，临床微生物学实验室通过 MALDI-TOF 对肺炎克雷伯菌复合体（包括 ）的准确鉴定将有助于阐明各物种的临床特征。近年来，细菌全基因组测序分析的广泛应用导致了新的细菌物种的提出和分类学的重新分类。临床微生物学实验室中细菌种属的准确鉴定方法对于积累各细菌种属的临床特征信息至关重要。洋葱伯克霍尔德菌是肺炎克雷伯菌复合体的成员，其与人类感染的关系日益受到关注，但迄今为止，可用于临床微生物学实验室的准确鉴定方法有限。本研究结果表明，使用更新的文库或基于网络的鉴定工具，MALDI-TOF 可准确鉴定 。准确的鉴定将促进对 临床特征的探索。
