摘要
      抗生素耐药性基因（ARGs）的表型表达会阻碍抗生素作为龈下器械辅助治疗牙周炎患者。本研究的目的是分析19例牙周炎患者龈下生物膜样品对氨苄青霉素-舒巴坦、克林霉素、多西环素和甲硝唑的表型和基因型耐药性之间的关系。用鸟枪测序分析样品，并在含有抗生素的微生物培养基上厌氧培养7天。使用MALDI-TOF-MS和16S核糖体RNA（rRNA）基因的序列分析，在物种水平上鉴定了所有生长的分离株。使用EUCAST断点测定表型抗性。八名患者的基因图谱与对测试抗生素的表型耐药性完全匹配。阳性预测值从克林霉素的1.00到多西环素的0.57和氨苄青霉素-舒巴坦的0.25不等。没有样本含有nimI基因。可以得出结论，抗生素耐药性可能是多基因的，基因可能是沉默的。每个携带erm基因的生物膜样品都具有表型抗性。cfx和tet基因的缺失与表型抗性的缺失分别相关100%至75%。nimI基因的缺失导致了一种假设，即几个物种之间的组成型耐药性可以解释对甲硝唑的耐药性。
Abstract
The phenotypic expression of antibiotic resistance genes (ARGs) can hamper the use of antibiotics as adjuncts to subgingival instrumentation in the treatment of periodontitis patients. The aim of the study was to analyze the relationship between the phenotypic and genotypic resistance against ampicillin-sulbactam, clindamycin, doxycycline and metronidazole of subgingival biofilm samples from 19 periodontitis patients. Samples were analyzed with shotgun sequencing and cultivated anaerobically for 7 days on microbiological culture media incorporating antibiotics. All growing isolates were identified to the species level using MALDI-TOF-MS and sequence analysis of the 16S ribosomal RNA (rRNA) gene. Phenotypic resistance was determined using EUCAST-breakpoints. The genetic profile of eight patients matched completely with phenotypical resistance to the tested antibiotics. The positive predictive values varied from 1.00 for clindamycin to 0.57 for doxycycline and 0.25 for ampicillin-sulbactam. No sample contained the nimI gene. It can be concluded that antibiotic resistance may be polygenetic and genes may be silent. Every biofilm sample harboring erm genes was phenotypic resistant. The absence of cfx and tet genes correlated to 100%, respectively, to 75%, with the absence of phenotypic resistance. The absence of nimI genes leads to the assumption that constitutive resistance among several species could explain the resistance to metronidazole.

https://www.mdpi.com/2079-6382/12/1/68