芝加哥天蓝与KOH涂片镜检对马拉色菌诊断的比较

Comparison of Modified Chicago Sky Blue Stain and Potassium Hydroxide Mount for the Diagnosis of Malassezia

目的以培养作为诊断标准,比较芝加哥天蓝涂片镜检和KOH涂片镜检对马拉色菌诊断的阳性率、阅片耗时等方面差异。方法收集门诊可疑马拉色菌感染患者皮屑标本,同时做真菌培养、芝加哥天蓝涂片、KOH涂片,培养阳性的281份标本,对芝加哥天蓝涂片镜检和KOH涂片镜检阳性率、阅片时间进行统计学分析比较。结果芝加哥天蓝可将马拉色菌的孢子或菌丝染成蓝色而皮屑等被染成浅紫红色杂质背景,阅片时间(70.99±12.61)s,KOH阅片时间(79.56±15.67)s,差异有统计学意义(P<0.05)。培养阳性的281例马拉色菌标本中芝加哥天蓝染色涂片镜检阳性193例,阳性率68.68%,KOH涂片镜检阳性179例,阳性率63.70%,差异有统计学意义(P<0.05)。结论芝加哥天蓝涂片为马拉色菌的诊断提供了一种简单快速、阳性率高、稳定性强、性价比好、结果易读取的检查方法。

Objective Using fungal culture as gold standard to compare the positive rate, screening time between modified Chicago sky blue （CSB） stain and potassium hydroxide （KOH） mount for Malassezia. Methods Skin scrapings were prospectively collected from outpatients with suspicion of Malassezia infection at our department. All the scrapings were examined with 10% KOH mount, 1% CSB stain and fungal cultures. Positive rates and screening time were compared between modified CSB stain and KOH mount in 281 culture positive samples. Results The CSB stain revealed short bluish hyphae and spherical spores for Malassezia spp against a purplish to pink background of cel-lular debris. The mean screening time for the CSB stain was significantly shorter than the KOH mount [ （70. 99 ± 12. 61 ）s vs （79.56 ± 15.67）s, P 〈 0. 05 ） ]. In the 281 culture positive samples, positive rates for CSB stain and KOH mount were 68.68% （ 193 ） and 63.70% （179） （P 〈 0. 05）, respectively. Conclusion The modified CBS stain is simple, quick, sensitive, reliable, and easy to read in the diagnosis of Malassezia spp.