Wright T L, Ellen R P, Lacroix J M, Sinnadurai S, Mittelman M W
Department of Periodontics, Faculty of Dentistry, University of Toronto, Ontario, Canada.
J Periodontal Res. 1997 Jul;32(5):473-7. doi: 10.1111/j.1600-0765.1997.tb00560.x.
Subgingival bacteria exist within a biofilm consisting of cells and extracellular matrix which may afford organisms protection from both antibiotics and components of the host immune system. MIC values for planktonic Porphyromonas gingivalis treated with metronidazole were compared with those obtained for the same strain in biofilms associated with hydroxyapatite (HA) surfaces. The treated biofilms were examined for growth and studied by scanning electron microscopy. A broth assay resulted in an MIC of 0.125 microgram/ml for metronidazole against P. gingivalis, P. gingivalis biofilms exhibited growth after treatment with 20 micrograms/ml metronidazole, which was 160 times the MIC for planktonic organisms. The results of this study indicate that biofilm-associated P. gingivalis may be resistant to metronidazole at concentrations which are usually attained by systemic administration.
龈下细菌存在于由细胞和细胞外基质组成的生物膜中，这可能为微生物提供对抗生素和宿主免疫系统成分的保护。将甲硝唑处理的浮游牙龈卟啉单胞菌的最低抑菌浓度（MIC）值与在与羟基磷灰石（HA）表面相关的生物膜中同一菌株获得的MIC值进行比较。检查处理后的生物膜的生长情况，并通过扫描电子显微镜进行研究。肉汤试验得出甲硝唑对牙龈卟啉单胞菌的MIC为0.125微克/毫升，牙龈卟啉单胞菌生物膜在用20微克/毫升甲硝唑处理后仍有生长，这是浮游生物MIC的160倍。本研究结果表明，与生物膜相关的牙龈卟啉单胞菌可能对全身给药通常达到的浓度的甲硝唑耐药。
