MYCOBACTERIUM CHELONEI MASQUERADING AS CORYNEBACTERIUM IN A CASE OF INFECTIOUS KERATITIS - A DIAGNOSTIC DILEMMA

Purpose. The diagnosis of Mycobacterium keratitis can often be missed both clinically and microbiologically and this report highlights one s uch case. Methods, Review of medical and microbiological records. Resu lts, We report a case of Mycobacterium keratitis in a 25-year-old man that was misdiagnosed as Corynebacterium keratitis at initial presenta tion. presence of partially stained and beaded bacilli in a Gram-stain ed smear of repeat corneal scrapings raised the suspicion of an unusua l organism. Ziehl-Neelsen staining of the decolorized Gram-stained sme ar and subculture on Lowenstein-Jensen medium helped us to establish t he diagnosis. Conclusions, A high degree of suspicion needs to be main tained, especially in cases in which (a) there is a history of corneal trauma involving a foreign body, (b) the Gram-stained smear of cornea l scrapings shows a paucity of organisms and the presence of partially stained and beaded bacilli in the presence of confluent growth of col onies resembling those of Corynebacterium, and (c) a typical corneal f eature like ''cracked windshield'' stromal lesion is seen, to avoid su ch a misdiagnosis. Inclusion of a Lowenstein-Jensen culture at the ini tial presentation, especially when the clinical presentation is atypic al, as seen in this case, will lead to an early diagnosis.