Ranjith Konduri, Sontam Bhavani, Sharma Savitri, Joseph Joveeta, Chathoth Kanchana N, Sama Kalyana C, Murthy Somasheila I, Shivaji Sisinthy
Jhaveri Microbiology Centre, Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Kallam Anji Reddy campus, Hyderabad, India.
Research scholar, Manipal University, Madhav Nagar, Udipi, Karnataka, India.
Invest Ophthalmol Vis Sci. 2017 Aug 1;58(10):4201-4209. doi: 10.1167/iovs.17-22003.
To determine the type of Candida species in ocular infections and to investigate the relationship of antifungal susceptibility profile to virulence factors.
Fifty isolates of yeast-like fungi from patients with keratitis, endophthalmitis, and orbital cellulitis were identified by Vitek-2 compact system and DNA sequencing of ITS1-5.8S-ITS2 regions of the rRNA gene, followed by phylogenetic analysis for phenotypic and genotypic identification, respectively. Minimum inhibitory concentration of six antifungal drugs was determined by E test/microbroth dilution methods. Phenotypic and genotypic methods were used to determine the virulence factors.
Phylogenetic analysis showed the clustering of all isolates into eight distinct groups with a major cluster formed Candida parapsilosis (n = 21), which was the most common species by both Vitek 2 and DNA sequencing. Using χ2 test no significant difference was noted between the techniques except that Vitek 2 did not identify C. viswanathii, C. orthopsilosis, and two non-Candida genera. Of 43 tested Candida isolates high susceptibility to amphotericin B (39/43, 90.6%) and natamycin (43/43, 100%) was noted. While none of the isolates produced coagulase, all produced esterase and catalase. The potential to form biofilm was detected in 23/43 (53.4%) isolates. Distribution of virulence factors by heat map analysis showed difference in metabolic activity of biofilm producers from nonbiofilm producers.
Identified by Vitek 2 and DNA sequencing methods C. parapsilosis was the most common species associated with eye infections. Irrespective of the virulence factors elaborated, the Candida isolates were susceptible to commonly used antifungal drugs such as amphotericin B and natamycin.
确定眼部感染中念珠菌的种类，并研究抗真菌药敏谱与毒力因子之间的关系。
采用Vitek-2 compact系统和rRNA基因ITS1-5.8S-ITS2区域的DNA测序，对50株来自角膜炎、眼内炎和眼眶蜂窝织炎患者的酵母样真菌进行鉴定，随后分别通过系统发育分析进行表型和基因型鉴定。采用E试验/微量肉汤稀释法测定六种抗真菌药物的最低抑菌浓度。采用表型和基因型方法确定毒力因子。
系统发育分析显示，所有分离株聚为八个不同的组，主要聚类为近平滑念珠菌（n = 21），这是Vitek 2和DNA测序中最常见的菌种。使用χ2检验，除Vitek 2未鉴定出维斯瓦纳特念珠菌、正平滑念珠菌和两个非念珠菌属外，两种技术之间未发现显著差异。在43株受试念珠菌分离株中，观察到对两性霉素B（39/43，90.6%）和那他霉素（43/43，100%）高度敏感。虽然没有分离株产生凝固酶，但所有分离株均产生酯酶和过氧化氢酶。在23/43（53.4%）的分离株中检测到形成生物膜的潜力。通过热图分析的毒力因子分布显示，生物膜产生者与非生物膜产生者的代谢活性存在差异。
通过Vitek 2和DNA测序方法鉴定，近平滑念珠菌是与眼部感染相关的最常见菌种。无论所阐述的毒力因子如何，念珠菌分离株对两性霉素B和那他霉素等常用抗真菌药物敏感。
