Anil S, Ellepola A N B, Samaranayake L P
Oral Biosciences, Faculty of Dentistry, University of Hong Kong, Hong Kong.
Mycopathologia. 2002;153(4):179-85. doi: 10.1023/a:1014932302518.
Oral candidiasis is the most common opportunistic infection in individuals infected with the human immunodeficiency virus. Though Candida albicans is the major aetiological agent, non-albicans species such Candida tropicalis are now emerging as important agents of such infection. The Candida cell surface hydrophobicity (CSH) is considered a critical factor contributing to its colonization potential and virulence. It is also known that brief exposure to sub-cidal concentrations of antifungal agents is a likely scenario in the oral environment where the administered drugs are diluted continuously due to the flushing action of saliva. Hence the objective of the present study was to compare the CSH of 10 isolates each of C. albicans and C. tropicalis from HIV-infected individuals following brief exposure (1 hour) of isolates to sub-therapeutic concentrations of nystatin, amphotericin B, ketoconazole, fluconazole and 5-flurocytosine. The CSH was assessed by a previously described biphasic aqueous-hydrocarbon assay. The mean percentage reduction of CSH of C. albicans following brief exposure to nystatin, amphotericin B, ketoconazole, fluconazole and 5-flurocytosine was 27.33 (p < 0.001), 21.34 (p < 0.05), 11.74 (p > 0.05), 18.4 (p > 0.05) and 14.64 (p > 0.05) respectively. The mean percentage reduction of CSH of C. tropicalis following brief exposure to nystatin, amphotericin B, ketoconazole, fluconazole and 5-flurocytosine was 33.81 (p < 0.01), 28.88 (p < 0.01), 12.6 (p > 0.05), 21.53 (p > 0.05) and 17.68 (p > 0.05) respectively. A significant interspecies variation in CSH was observed for nystatin and amphoterecin B. Overall the results reveal that the CSH of C. albicans is affected to a significantly lesser degree compared with C. tropicalis when exposed to the antifungals. These data further illustrate another mode of action of antifungals on Candida leading to a reduction in the CSH and thereby the yeast adherence to host tissues.
口腔念珠菌病是感染人类免疫缺陷病毒个体中最常见的机会性感染。虽然白色念珠菌是主要的病原体，但热带念珠菌等非白色念珠菌物种如今正成为此类感染的重要病原体。念珠菌细胞表面疏水性（CSH）被认为是其定植潜力和毒力的关键因素。还已知在口腔环境中，由于唾液的冲洗作用，所施用的药物会持续稀释，短暂暴露于亚致死浓度的抗真菌剂是很可能发生的情况。因此，本研究的目的是比较来自HIV感染者的10株白色念珠菌和10株热带念珠菌在将菌株短暂暴露（1小时）于制霉菌素、两性霉素B、酮康唑、氟康唑和5-氟胞嘧啶的亚治疗浓度后其CSH。通过先前描述的双相水-烃测定法评估CSH。白色念珠菌短暂暴露于制霉菌素、两性霉素B、酮康唑、氟康唑和5-氟胞嘧啶后CSH的平均降低百分比分别为27.33（p<0.001）、21.34（p<0.05）、11.74（p>0.05）、18.4（p>0.05）和14.64（p>0.05）。热带念珠菌短暂暴露于制霉菌素、两性霉素B、酮康唑、氟康唑和5-氟胞嘧啶后CSH的平均降低百分比分别为33.81（p<0.01）、28.88（p<0.01）、12.6（p>0.05）、21.53（p>0.05）和17.68（p>0.05）。观察到制霉菌素和两性霉素B在CSH方面存在显著的种间差异。总体而言，结果表明，与热带念珠菌相比，白色念珠菌的CSH在暴露于抗真菌剂时受到的影响程度要小得多。这些数据进一步说明了抗真菌剂对念珠菌的另一种作用方式，即导致CSH降低，从而使酵母对宿主组织的黏附减少。
