Hungarian Anaerobe Reference Laboratory, Institute of Clinical Microbiology, University of Szeged, 6725 Szeged, Semmelweis u 6, Hungary.
Anaerobe. 2013 Apr;20:20-6. doi: 10.1016/j.anaerobe.2013.01.007. Epub 2013 Feb 26.
Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used today for species determination of bacteria and fungi in routine microbiological laboratories, and can also be used for subtyping of bacteria, such as Bacteroides fragilis. Propionibacterium acnes is frequently referred to as an anaerobic skin commensal of relatively low pathogenicity. In addition to its accepted pathogenic role in acne, P. acnes is now emerging as an important opportunistic pathogen in many other clinical situations, including late-stage prosthetic joint infections, osteomyelitis, endocarditis, endophthalmitis, post-neurosurgical infections and possibly prostate cancer. At the population genetic level, P. acnes can be differentiated into a number of distinct phylogroups, known as types IA1, IA2, IB, IC, II and III, which may be associated with different types of infections and clinical conditions. The aim of the present study was to evaluate MS-based typing for resolution of these genetic groups after routine identification by MALDI-TOF MS (Bruker MALDI Biotyper). The software package ClinProTools 2.2 was used to analyze the protein based mass spectra of reference strains belonging to types IA, IB, IC, II and III. Phylogroup-specific peaks and peak shifts were then identified visually. In addition, peak variations between the different types of P. acnes were investigated by using FlexAnalysis 3.3 software (Bruker). A differentiating library was created, which was used to type further 48 clinical isolates of P. acnes. Typing data obtained by MALDI-TOF MS were then compared with the results from Multilocus Sequence Typing (MLST). Most of the clinical isolates (n = 19) belonged to the type IA grouping according to MALDI-TOF MS. By MLST, all isolates were identified as type IA1. Twenty-one clinical isolates belonged to the type IB cluster based on both MALDI-TOF MS and MLST typing. Eight clinical isolates were identified as type II strains by both typing methods and all the type III reference strains could be distinguished by the presence of a unique type III-specific peak (7238 Da) by the MALDI-TOF MS. Our study demonstrates that MALDI-TOF MS is a reliable and powerful tool for rapid identification and typing of P. acnes strains from the main genetic divisions of the species.
基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）目前广泛用于常规微生物实验室中细菌和真菌的种属鉴定，也可用于细菌的分型，如脆弱拟杆菌。痤疮丙酸杆菌通常被认为是一种相对低致病性的厌氧皮肤共生菌。除了公认的在痤疮中的致病作用外，痤疮丙酸杆菌现在在许多其他临床情况下也作为一种重要的机会性病原体出现，包括晚期假体关节感染、骨髓炎、心内膜炎、眼内炎、神经外科手术后感染，以及可能的前列腺癌。在群体遗传水平上，痤疮丙酸杆菌可以分为许多不同的系统发育群，称为 IA1、IA2、IB、IC、II 和 III 型，这些型可能与不同类型的感染和临床情况有关。本研究旨在评估 MALDI-TOF MS（布鲁克 MALDI Biotyper）常规鉴定后，基于 MS 的分型是否能解析这些遗传群。使用 ClinProTools 2.2 软件包分析属于 IA、IB、IC、II 和 III 型的参考菌株的基于蛋白质的质谱。然后通过视觉识别出特定于菌型的峰和峰偏移。此外，还通过 FlexAnalysis 3.3 软件（布鲁克）研究了不同类型痤疮丙酸杆菌之间的峰变化。创建了一个区分库，用于对进一步的 48 株临床痤疮丙酸杆菌进行分型。然后将 MALDI-TOF MS 获得的分型数据与多位点序列分型（MLST）的结果进行比较。根据 MALDI-TOF MS，大多数临床分离株（n=19）属于 IA 分组。通过 MLST，所有分离株均被鉴定为 IA1 型。根据 MALDI-TOF MS 和 MLST 分型，21 株临床分离株属于 IB 群。两种分型方法均鉴定 8 株临床分离株为 II 型菌株，MALDI-TOF MS 可以通过存在独特的 III 型特异性峰（7238 Da）来区分所有 III 型参考菌株。本研究表明，MALDI-TOF MS 是一种快速鉴定和分型痤疮丙酸杆菌菌株的可靠且强大的工具，可用于鉴定该物种的主要遗传分支。
