Department of Endodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
J Endod. 2022 Feb;48(2):200-207. doi: 10.1016/j.joen.2021.11.003. Epub 2021 Nov 17.
Fungi are considered to be opportunistic pathogens that may play a significant role in the pathogenesis of endodontic infections. The main purpose of this study was to assess the prevalence of 2 selected genera of fungi, Candida albicans and Aspergillus spp., using real-time polymerase chain reaction (RT-PCR) and to compare the findings with the respective ones obtained by a culture-dependent approach, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). A secondary aim was to assess the presence of other bacteria growing under aerobic conditions.
Microbial samples were obtained from the root canals of 60 teeth associated with pulp necrosis and apical periodontitis. DNA was extracted, and RT-PCR was applied for the detection of C. albicans and Aspergillus spp. pathogenic subtypes. In addition, MALDI-ToF MS was performed to identify microorganisms grown under aerobic conditions.
Based on RT-PCR, Aspergillus was detected in 8 cases, whereas C. albicans was detected in 4 cases. Using MALDI-ToF MS, no trace of Aspergillus was detected, whereas C. albicans was identified in 2 cases. Significant differences were revealed in the detection potential for Aspergillus spp. between MALDI-ToF MS and RT-PCR (P = .01); conversely, this was not the case for C. albicans (P = .50). After MALDI-ToF MS, 35 samples showed evidence of bacterial growth. The vast majority was colonized by Achromobacter xylosoxidans followed by Lactobacillus spp., Methylobacterium spp., and Enterococcus faecalis.
The findings confirm the presence of fungi in primarily infected canals with apical periodontitis as well as some rarely inspected aerobic bacterial species. A. xylosoxidans was prevalent; however, the clinical relevance of its presence needs to be investigated further.
真菌被认为是机会性病原体，可能在牙髓感染的发病机制中起重要作用。本研究的主要目的是使用实时聚合酶链反应（RT-PCR）评估 2 种选定真菌属（白色念珠菌和曲霉菌属）的流行率，并将结果与基于培养的方法（基质辅助激光解吸/电离飞行时间质谱法，MALDI-ToF MS）获得的结果进行比较。次要目的是评估在需氧条件下生长的其他细菌的存在情况。
从 60 颗伴有牙髓坏死和根尖周炎的牙齿的根管中获得微生物样本。提取 DNA，应用 RT-PCR 检测白色念珠菌和曲霉菌属的致病性亚型。此外，还进行了 MALDI-ToF MS 以鉴定在需氧条件下生长的微生物。
基于 RT-PCR，在 8 例中检测到曲霉菌，在 4 例中检测到白色念珠菌。使用 MALDI-ToF MS，未检测到曲霉菌的痕迹，但在 2 例中鉴定出白色念珠菌。MALDI-ToF MS 和 RT-PCR 检测曲霉菌属的检测潜力存在显著差异（P=.01）；相反，对于白色念珠菌则不然（P=.50）。MALDI-ToF MS 后，35 个样本显示有细菌生长的证据。绝大多数被木糖氧化无色杆菌定植，其次是乳酸杆菌属、甲基杆菌属和粪肠球菌。
这些发现证实了在有根尖周炎的主要感染根管中存在真菌，以及一些很少检查到的需氧细菌。木糖氧化无色杆菌很普遍；然而，其存在的临床相关性需要进一步研究。
