Cornea & Anterior Segment Service, L V Prasad Eye Institute, Bhubaneswar, Odisha, 751024, India.
Ocular Microbiology Service, L V Prasad Eye Institute, Bhubaneswar, Odisha, 751024, India.
Indian J Med Microbiol. 2022 Oct-Dec;40(4):521-524. doi: 10.1016/j.ijmmb.2022.08.003. Epub 2022 Aug 27.
To evaluate the efficacy of various staining techniques for detection of Pythium in keratitis cases.
Data of nineteen consecutive culture-positive cases of Pythium keratitis were retrospectively analysed. Corneal scrapings and corneal buttons (in the cases which underwent therapeutic penetrating keratoplasty [TPK]) were sent for microbiological and histopathological examination. The direct smears were stained with Potassium hydroxide and calcofluor white (KOH + CFW), Gram and Iodine-Potassium Iodide-Sulphuric Acid (IKI-HSO) stains. The corneal buttons were stained with Gomori's Methanamine Silver (GMS), Periodic Acid-Schiff (PAS) and Iodine-Potassium Iodide-Sulphuric Acid (IKI-HSO) stains. The positivity of various stains in detecting Pythium was studied.
Gram and KOH + CFW staining from smear was done in 16 out of 19 (84.2%) cases. KOH + CFW and Gram stains were suggestive of Pythium in 10 (62.5%) and 7 (43.8%) cases, respectively. IKI-HSO staining in scraping samples was positive for Pythium in all the 4 (100%) cases in which it was performed. Half corneal buttons were positive for Pythium with IKI-HSO stain as well as GMS stain in all the 18 cases that underwent TPK (100%). PAS stain showed weak to faint pink staining of Pythium filaments in 7 out of 18 cases (38.9%).
IKI-HSO stain followed by KOH + CFW stain detects Pythium filaments most accurately in corneal scraping samples from keratitis patients, although the differences were not statistically significant. The positivity of the stains depends on astute observation by an experienced ocular microbiologist and pathologist.
评估各种染色技术在检测角膜炎中皮炎丝菌的效果。
回顾性分析 19 例连续培养阳性的皮炎丝菌角膜炎病例。对角膜刮片和（行穿透性角膜移植术[TPK]的病例中的）角膜活检组织进行微生物和组织病理学检查。直接涂片用氢氧化钾和钙荧光素（KOH+CFW）、革兰氏和碘-碘化钾-硫酸（IKI-HSO）染色。角膜活检组织用 Gomori 六胺银（GMS）、过碘酸雪夫（PAS）和碘-碘化钾-硫酸（IKI-HSO）染色。研究了各种染色方法检测皮炎丝菌的阳性率。
19 例中有 16 例（84.2%）进行了涂片革兰氏和 KOH+CFW 染色。KOH+CFW 和革兰氏染色分别在 10 例（62.5%）和 7 例（43.8%）病例中提示皮炎丝菌。在进行 IKI-HSO 染色的 4 例（100%）刮片样本中，均检测到皮炎丝菌阳性。在接受 TPK 的 18 例（100%）病例中，半块角膜活检组织的 IKI-HSO 染色和 GMS 染色均显示皮炎丝菌阳性。PAS 染色在 18 例中有 7 例（38.9%）显示皮炎丝菌丝状结构弱到淡粉色染色。
虽然差异无统计学意义，但在角膜炎患者的角膜刮片样本中，IKI-HSO 染色后再行 KOH+CFW 染色可最准确地检测皮炎丝菌丝。染色的阳性率取决于经验丰富的眼微生物学家和病理学家的敏锐观察。
