Ellepola Arjuna N B, Chandy Rachel, Khan Zia U
Faculty of Dentistry, Department of Bioclinical Sciences, Health Sciences Center, Kuwait University, Safat, Kuwait.
Faculty of Medicine, Department of Microbiology, Health Sciences Center, Kuwait University, Safat, Kuwait.
Mycoses. 2015 Sep;58(9):536-43. doi: 10.1111/myc.12353. Epub 2015 Jul 22.
The phenomenon of postantifungal effect (PAFE), which is the suppression of candidal growth following brief exposure to antifungal agents, is linked with candidal pathogenicity. Adhesion to buccal epithelial cells (BEC), germ tube (GT) formation and relative cell surface hydrophobicity (CSH) are all adhesion traits of candidal pathogenicity. Ability to produce haemolysin by Candida species is also a determinant of its pathogenicity. There is no information on either the PAFE or its impact on adhesion traits and haemolysin production of oral Candida dubliniensis isolates following exposure to 5-fluorocytosine (5-FC). Hence, the focus of this investigation was to research the in vitro PAFE, adhesion to BEC, GT formation, relative CSH and haemolysin production on 20 C. dubliniensis isolates following exposure to 5-FC. Following obtaining the minimum inhibitory concentration (MIC) of 5-FC, isolates of C. dubliniensis were exposed to sub-lethal concentrations (×3 MIC) of 5-FC for 1 h. After this brief exposure, the antimycotic was removed and PAFE, adhesion to BEC, GT formation, relative CSH and haemolysin production was determined by formerly described in vitro methods. MIC (μg/ml) of C. dubliniensis isolates to 5-FC ranged from 0.002 to 0.125. The mean PAFE (hours) elicited by 5-FC on C. dubliniensis isolates was approximately 1 h. Exposure to 5-FC suppressed the ability of C. dubliniensis isolates to adhere BEC, GT formation, relative CSH and haemolysin activity by a mean percentage reduction in 50.98%, 29.51%, 36.79% and 12.75% (P < 0.001 for all) respectively. Therefore, brief exposure of C. dubliniensis isolates to 5-FC appears to exert an antifungal effect by subduing its growth, adhesion traits as well as haemolysin production.
抗真菌后效应（PAFE）现象是指念珠菌短暂接触抗真菌药物后生长受到抑制，它与念珠菌致病性有关。黏附于颊上皮细胞（BEC）、形成芽管（GT）以及相对细胞表面疏水性（CSH）都是念珠菌致病性的黏附特性。念珠菌产生溶血素的能力也是其致病性的一个决定因素。关于暴露于5-氟胞嘧啶（5-FC）后口腔都柏林念珠菌分离株的PAFE及其对黏附特性和溶血素产生的影响，目前尚无相关信息。因此，本研究的重点是研究20株都柏林念珠菌分离株在暴露于5-FC后的体外PAFE、对BEC的黏附、GT形成、相对CSH和溶血素产生情况。在获得5-FC的最低抑菌浓度（MIC）后，将都柏林念珠菌分离株暴露于亚致死浓度（×3 MIC）的5-FC中1小时。短暂暴露后，去除抗真菌药物，通过先前描述的体外方法测定PAFE、对BEC的黏附、GT形成、相对CSH和溶血素产生情况。都柏林念珠菌分离株对5-FC的MIC（μg/ml）范围为0.002至0.125。5-FC对都柏林念珠菌分离株产生的平均PAFE（小时）约为1小时。暴露于5-FC使都柏林念珠菌分离株黏附BEC、形成GT、相对CSH和溶血素活性的能力分别平均降低了50.98%、29.51%、36.79%和12.75%（所有P均<0.001）。因此，都柏林念珠菌分离株短暂暴露于5-FC似乎通过抑制其生长、黏附特性以及溶血素产生发挥抗真菌作用。
