Garg P, Athmanathan S, Rao G N
Sight Savers' Corneal Training Centre, L.V. Prasad Eye Institute, Hyderabad, India.
Cornea. 1998 Mar;17(2):230-2. doi: 10.1097/00003226-199803000-00021.
The diagnosis of Mycobacterium keratitis can often be missed both clinically and microbiologically and this report highlights one such case.
Review of medical and microbiological records.
We report a case of Mycobacterium keratitis in a 25-year-old man that was misdiagnosed as Corynebacterium keratitis at initial presentation. Presence of partially stained and beaded bacilli in a Gram-stained smear of repeat corneal scrapings raised the suspicion of an unusual organism. Ziehl-Neelsen staining of the decolorized Gram-stained smear and subculture on Löwenstein-Jensen medium helped us to establish the diagnosis.
A high degree of suspicion needs to be maintained, especially in cases in which (a) there is a history of corneal trauma involving a foreign body, (b) the Gram-stained smear of corneal scrapings shows a paucity of organisms and the presence of partially stained and beaded bacilli in the presence of confluent growth of colonies resembling those of Corynebacterium, and (c) a typical corneal feature like "cracked windshield" stromal lesion is seen, to avoid such a misdiagnosis. Inclusion of a Löwenstein-Jensen culture at the initial presentation, especially when the clinical presentation is atypical, as seen in this case, will lead to an early diagnosis.
角膜分枝杆菌角膜炎的诊断在临床和微生物学方面常常被漏诊，本报告重点介绍了这样一个病例。
回顾医学和微生物学记录。
我们报告了一例25岁男性的角膜分枝杆菌角膜炎病例，该病例在初次就诊时被误诊为棒状杆菌角膜炎。重复角膜刮片的革兰氏染色涂片中存在部分染色且呈珠状的杆菌，这引发了对一种不寻常病原体的怀疑。对脱色后的革兰氏染色涂片进行萋-尼染色以及在罗-琴培养基上进行传代培养，帮助我们确诊。
需要保持高度怀疑，尤其是在以下情况的病例中：（a）有涉及异物的角膜外伤史；（b）角膜刮片的革兰氏染色涂片显示病原体数量少，且在类似棒状杆菌的菌落融合生长的情况下存在部分染色且呈珠状的杆菌；（c）出现典型的角膜特征，如“破碎挡风玻璃”样基质病变，以避免此类误诊。在初次就诊时进行罗-琴培养，尤其是当临床表现不典型时，如本病例所见，将有助于早期诊断。
