Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
Institute of Photomedicine, Shanghai Skin Disease Hospital, Tongji University School of Medicine, Shanghai, China.
Photochem Photobiol. 2020 May;96(3):611-617. doi: 10.1111/php.13241. Epub 2020 Apr 24.
Moraxella catarrhalis is one of the major otopathogens of otitis media (OM) in childhood. M. catarrhalis tends to form biofilm, which contributes to the chronicity and recurrence of infections, as well as resistance to antibiotic treatment. In this study, we aimed to investigate the effectiveness of antimicrobial blue light (aBL; 405 nm), an innovative nonpharmacological approach, for the inactivation of M. catarrhalis OM. M. catarrhalis either in planktonic suspensions or 24-h old biofilms were exposed to aBL at the irradiance of 60 mW cm . Under an aBL exposure of 216 J cm , a >4-log colony-forming units (CFU) reduction in planktonic suspensions and a >3-log CFU reduction in biofilms were observed. Both transmission electron microscopy and scanning electron microscopy revealed aBL-induced morphological damage in M. catarrhalis. Ultraperformance liquid chromatography results indicated that protoporphyrin IX and coproporphyrin were the two most abundant species of endogenous photosensitizing porphyrins. No statistically significant reduction in the viability of HaCaT cells was observed after an aBL exposure of up to 216 J cm . Collectively, our results suggest that aBL is potentially an effective and safe alternative therapy for OM caused by M. catarrhalis. Further in vivo studies are warranted before this optical approach can be moved to the clinics.
卡他莫拉菌是儿童中耳炎（OM）的主要耳病原体之一。卡他莫拉菌倾向于形成生物膜，这导致感染的慢性化和复发，并对抗生素治疗产生耐药性。在这项研究中，我们旨在研究抗菌蓝光（aBL；405nm）作为一种创新的非药物方法，对卡他莫拉菌 OM 的灭活效果。无论是在浮游悬液还是 24 小时龄生物膜中，卡他莫拉菌都在 60mW/cm 的辐照度下暴露于 aBL。在 aBL 暴露 216J/cm 下，浮游悬液中的 CFU 减少了>4 对数，生物膜中的 CFU 减少了>3 对数。透射电子显微镜和扫描电子显微镜都显示 aBL 诱导了卡他莫拉菌的形态损伤。超高效液相色谱结果表明，原卟啉 IX 和粪卟啉是两种最丰富的内源性光敏卟啉。在高达 216J/cm 的 aBL 暴露下，HaCaT 细胞的活力没有明显下降。综上所述，我们的研究结果表明，aBL 可能是治疗卡他莫拉菌引起的 OM 的一种有效且安全的替代疗法。在这种光学方法应用于临床之前，还需要进行进一步的体内研究。
