Prospective study on combined use of Sabouraud dextrose agar and blood agar for improved recovery of etiological agents in mycotic and Pythium keratitis.

We evaluated the effectiveness of using blood agar (BA) and Sabouraud dextrose agar (SDA) together to isolate fungi and Pythium insidiosum for the diagnosis of fungal and Pythium keratitis respectively. The overall recovery rate was higher in SDA than BA (93.75 % vs 88.28 %; p = 0.595). BA demonstrated lower isolation of dematiaceous fungi (unadjusted p = 0.039: FDR adjusted p = 0.062). 11.71 % and 6.25 % of fungal isolates were not recovered on BA and SDA, respectively. While BA showed faster growth of fungi than SDA (unadjusted p = 0.002; FDR adjusted p = 0.005), both BA and SDA showed rapid recovery of Aspergillus spp. as compared to Fusarium spp. (unadjusted p < 0.001; FDR adjusted p = 0.004). The combined use of both media may enhance detection of certain fungi missed by either medium alone, hence guiding the appropriate patient management.