BACKGROUND: To compare two different methods of corneal culture in infectious keratitis: multiple sampling for direct inoculation and enrichment (standard method) and a single sample via transport medium for indirect inoculation (indirect inoculation method). METHODS: Prospective inclusion of patients fulfilling predefined criteria of infectious keratitis undergoing corneal culture according to both studied methods in a randomized order. RESULTS: The standard method resulted in a significantly higher proportion of positive culture outcomes among the 94 included episodes of infectious keratitis (61%; 57/94) than the indirect inoculation method (44%; 41/94) (p = 0.002) and a significantly higher proportion of microorganisms than the indirect inoculation method, with a Cohen's kappa of 0.38 (95% CI: 0.28-0.49) for agreement between the methods. Subanalysis of culture results showed that direct inoculation on gonococcal agar only combined with the indirect inoculation method resulted in a similar rate of culture positive patients and proportion of detected microorganisms to the standard method. CONCLUSION: Indirect inoculation of one corneal sample cannot replace direct inoculation of multiple corneal samples without loss of information. A combination of directly and indirectly inoculated samples can reduce the number of corneal samples by four without statistically significant differences in culture outcome or in the proportion of detected microorganisms.
BACKGROUND: To compare two different methods of corneal culture in infectious keratitis: multiple sampling for direct inoculation and enrichment (standard method) and a single sample via transport medium for indirect inoculation (indirect inoculation method). METHODS: Prospective inclusion of patients fulfilling predefined criteria of infectious keratitis undergoing corneal culture according to both studied methods in a randomized order. RESULTS: The standard method resulted in a significantly higher proportion of positive culture outcomes among the 94 included episodes of infectious keratitis (61%; 57/94) than the indirect inoculation method (44%; 41/94) (p = 0.002) and a significantly higher proportion of microorganisms than the indirect inoculation method, with a Cohen's kappa of 0.38 (95% CI: 0.28-0.49) for agreement between the methods. Subanalysis of culture results showed that direct inoculation on gonococcalagar only combined with the indirect inoculation method resulted in a similar rate of culture positive patients and proportion of detected microorganisms to the standard method. CONCLUSION: Indirect inoculation of one corneal sample cannot replace direct inoculation of multiple corneal samples without loss of information. A combination of directly and indirectly inoculated samples can reduce the number of corneal samples by four without statistically significant differences in culture outcome or in the proportion of detected microorganisms.
Entities:
Keywords:
corneal culture; direct inoculation; indirect inoculation; infectious keratitis
Authors: Alejandro Lichtinger; Sonia N Yeung; Peter Kim; Maoz D Amiran; Alfonso Iovieno; Uri Elbaz; Judy Y F Ku; Rachel Wolff; David S Rootman; Allan R Slomovic Journal: Ophthalmology Date: 2012-05-23 Impact factor: 12.079
Authors: Stephen B Kaye; Prasad G Rao; Godfrey Smith; John A Scott; Sharon Hoyles; Clare E Morton; Colin Willoughby; Mark Batterbury; Graham Harvey Journal: J Clin Microbiol Date: 2003-07 Impact factor: 5.948