Department of Surgery, School of Medicine, University of Pittsburgh.
Division of Pediatric General and Thoracic Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pennsylvania.
Clin Infect Dis. 2016 Jul 1;63(1):71-78. doi: 10.1093/cid/ciw208. Epub 2016 Apr 7.
Lumenal obstruction has typically been regarded as the cause of acute appendicitis (AA). Recent evidence including data from "antibiotics first" trials suggests that this disease may result from invasion of the appendix by specific pathogens. Small studies have identified an abundance of bacteria from the genus Fusobacterium in appendixes from patients with AA. We aimed to validate these findings in a larger cohort of children with appendicitis in addition to profiling the appendiceal microbiota in a population of children without appendicitis.
Appendix swabs were collected from children undergoing appendectomy for AA (n = 60), incidental appendectomy for reasons other than appendicitis (n = 18), or ileocecectomy for inflammatory bowel disease (n = 7), in addition to samples from other sites. Bacterial 16S ribosomal RNA gene sequences from each sample were amplified, sequenced, and analyzed with the UPARSE and QIIME programs.
We found that the normal human appendix harbors populations of Fusobacteria that are generally absent in fecal samples from healthy adults and children. In patients with AA, Fusobacteria populations proliferate and often persist despite several weeks of broad-spectrum antibiotics prior to surgery. Relative to non-AA samples, AA samples were depleted of sequences from the genus Bacteroides Phylogenetic analysis of sequence data indicates that F. nucleatum, F. necrophorum, and F. varium are the species of Fusobacterium observed in AA samples.
These results indicate that the appendiceal niche harbors distinct microbial populations that likely contribute to the pathogenesis of appendicitis, which may one day be leveraged to improve the diagnosis and/or treatment of patients with AA.
管腔阻塞通常被认为是急性阑尾炎（AA）的原因。最近的证据，包括“抗生素优先”试验的数据表明，这种疾病可能是由于特定病原体侵犯阑尾引起的。一些小型研究已经在 AA 患者的阑尾中发现了丰富的梭杆菌属细菌。我们旨在通过在更大的阑尾炎患儿队列中验证这些发现，并在没有阑尾炎的儿童人群中分析阑尾微生物组，从而进一步证实这些发现。
从因 AA 而行阑尾切除术的儿童（n = 60）、因非阑尾炎原因而行阑尾切除术的儿童（n = 18）或因炎症性肠病而行回盲肠切除术的儿童（n = 7）中采集阑尾拭子，以及来自其他部位的样本。对每个样本的细菌 16S 核糖体 RNA 基因序列进行扩增、测序，并使用 UPARSE 和 QIIME 程序进行分析。
我们发现，正常人类阑尾中存在通常不存在于健康成人和儿童粪便样本中的梭杆菌属种群。在 AA 患者中，尽管在手术前数周使用广谱抗生素，但梭杆菌属种群仍会增殖并经常持续存在。与非 AA 样本相比，AA 样本中缺乏属 Bacteroides 的序列。序列数据分析表明，在 AA 样本中观察到的梭杆菌属物种是 F. nucleatum、F. necrophorum 和 F. varium。
这些结果表明，阑尾腔隙中存在独特的微生物种群，这些种群可能有助于阑尾炎的发病机制，这些种群有朝一日可能被用来改善 AA 患者的诊断和/或治疗。
