Peguda Hari Kumar, Mahbub Saabah B, Sherpa Tashi Doma, Subedi Dinesh, Habibalahi Abbas, Anwer Ayad G, Gu Zi, Willcox Mark D P, Goldys Ewa M, Carnt Nicole A
School of Optometry and Vision Science, University of New South Wales, Sydney 2052, Australia.
ARC Centre of Excellence for Nanoscale Biophotonics, Graduate School of Biomedical Engineering, University of New South Wales, Sydney 2052, Australia.
Pathogens. 2021 Jul 14;10(7):894. doi: 10.3390/pathogens10070894.
Keratitis (AK) can lead to substantial vision loss and morbidity among contact lens wearers. Misdiagnosis or delayed diagnosis is a major factor contributing to poor outcomes of AK. This study aimed to assess the effect of two antibiotics and one anaesthetic drug used in the diagnosis and nonspecific management of keratitis on the autofluorescence patterns of and two common bacteria that may also cause keratitis. ATCC 30868, ATCC 9027, and ATCC 6538 were grown then diluted in either PBS (bacteria) or ¼ strength Ringer's solution () to give final concentrations of 0.1 OD at 660 nm or 10 cells/mL. Cells were then treated with ciprofloxacin, tetracycline, tetracaine, or no treatment (naïve). Excitation-emission matrices (EEMs) were collected for each sample with excitation at 270-500 nm with increments in 5 nm steps and emission at 280-700 nm at 2 nm steps using a Fluoromax-4 spectrometer. The data were analysed using MATLAB software to produce smoothed color-coded images of the samples tested. exhibited a distinctive fluorescence pattern compared to bacteria. The addition of antibiotics and anaesthetic had variable effects on autofluorescence. Tetracaine altered the fluorescence of all three microorganisms, whereas tetracycline did not show any effect on the fluorescence. Ciprofloxacin produced changes to the fluorescence pattern for the bacteria, but not . Fluorescence spectroscopy was able to differentiate from in vitro. There is a need for further assessment of the fluorescence pattern for different strains of and bacteria. Additionally, analysis of the effects of anti-amoebic drugs on the fluorescence pattern of and bacteria would be prudent before in vivo testing of the fluorescence diagnostic approach in the animal models.
棘阿米巴角膜炎（AK）可导致隐形眼镜佩戴者出现严重视力丧失和发病。误诊或诊断延迟是导致AK不良预后的主要因素。本研究旨在评估用于角膜炎诊断和非特异性治疗的两种抗生素和一种麻醉药物对棘阿米巴和两种也可能引起角膜炎的常见细菌自发荧光模式的影响。将ATCC 30868、ATCC 9027和ATCC 6538培养后，在磷酸盐缓冲液（用于细菌）或1/4强度林格氏溶液（用于棘阿米巴）中稀释，使在660nm处的最终浓度为0.1 OD或10个细胞/毫升。然后将细胞用环丙沙星、四环素、丁卡因处理，或不进行处理（未处理）。使用Fluoromax - 4光谱仪，以5nm步长在270 - 500nm激发，以2nm步长在280 - 700nm发射，为每个样品收集激发 - 发射矩阵（EEMs）。使用MATLAB软件分析数据，以生成测试样品的平滑彩色编码图像。与细菌相比，棘阿米巴呈现出独特的荧光模式。添加抗生素和麻醉剂对自发荧光有不同影响。丁卡因改变了所有三种微生物的荧光，而四环素对荧光没有任何影响。环丙沙星使细菌的荧光模式发生变化，但对棘阿米巴没有影响。荧光光谱能够在体外区分棘阿米巴和细菌。需要进一步评估不同菌株的棘阿米巴和细菌的荧光模式。此外，在动物模型中对荧光诊断方法进行体内测试之前，分析抗阿米巴药物对棘阿米巴和细菌荧光模式的影响是明智的。
