R. Lin et al., COMPARATIVE EFFICACY OF TOPICAL CIPROFLOXACIN FOR TREATING MYCOBACTERIUM-FORTUITUM AND MYCOBACTERIUM-CHELONAE KERATITIS IN AN ANIMAL-MODEL, American journal of ophthalmology, 117(5), 1994, pp. 657-662
Mycobacterium fortuitum and M. chelonae are the two most common causes
of nontuberculous mycobacterial keratitis, and they may be difficult
to differentiate at diagnosis. Mycobacterium fortuitum is generally mo
re sensitive to ciprofloxacin in vitro than is M. chelonae. Using a ra
bbit model, we compared the efficacy of topical ciprofloxacin (3 mg/ml
) against M. chelonae keratitis to its efficacy against M. fortuitum k
eratitis. After four days of therapy, ciprofloxacin significantly redu
ced the number of both organisms in treated eyes compared to Untreated
control eyes (both P values < .001). Mean culture ratios (colony-form
ing,units in treated eye divided by colony-forming units in untreated
eye for each rabbit) were used to compare efficacy between groups. Whe
n all treated animals were considered, no significant difference was f
ound between groups (P = .13). When outlier values were exclude;ii cip
rofloxacin was more effective against M. fortuitum than M. chelonae (P
= .01). When treated and untreated eyes were compared after therapy i
n the M. fortuitum group, ciprofloxacin treatment was associated with
a reduction in mean stromal infiltrate area (P = .03) and in the tende
ncy to form satellite lesions (P = .07). A clinical effect was not obs
erved in the M. chelonae group. Although ciprofloxacin is effective ag
ainst both organisms, it appears to be less effective against M. chelo
nae than M. fortuitum in vivo.