Dr Comparison of CHROMAgar with Corn Meal Agar for the Speciation of Candida isolated from clinical samples.

Nil

Abstract

Candida species constitute normal flora of the skin, mucous membranes  and gastrointestinal tract but at the same time serve as big reservoir of endogenous opportunists causing secondary infection in individuals with underlying immunocompromised status. Speciation of Candida is gaining importance due to their resistance to commonly used antifungals and  varied antifungal susceptibility pattern. Yeast identification has always posed a challenge in front of clinical microbiological laboratories.  In this scenario, CHROMagar Candida, a chromogenic species-specific, cost effective media can be used for simultaneous isolation and  presumptive identification particularly in poly-fungal specimens in 48-72hrs in this era of emergence of Non albicans Candida.(NAC). Incorporating Corn Meal Agar for the purpose of identification on basis of morphological features can give an added advantage in the process. Aim:In this study we compared Candida species isolated from different clinical samples on CHROM agar with the Corn Meal Agar. Furether, identification via Vitek- 2 was done to note  the trend in resistance pattern of the isolated Candida species.

Material and Methods:In our prospective study conducted for duration of 6 months from Feb 2023 to July 2023,81 Candida isolates were obtained from various clinical specimens like high vaginal swab, blood,  pus, skin scrapings,sputum, bronchoalveolar lavage (BAL), endotracheal secretions etc. which were subjected to KOH mount and then sub-cultured on SDA with chloramphenicol and incubated aerobically at 37⁰C for 24-48hrs. From the growth on SDA , further inoculation was done on CHROMAgar and Corn Meal Agar(CMA) followed by additional identification and susceptibility via Vitek-2 and three were compared in terms of their sensitivity and specificity for isolation of various Candida species. 

Results: Maximum Candida isolates were obtained from blood (18) followed by high vaginal swabs(17),pus( 12), nail clippings (10) while single isolate was recovered from patient with otorrhoea. The most common risk factor was found to be prolonged antibiotic therapy. Non albicans Candida was isolated at higher rate 42(52%) than Candida albicans 39(48%). Amongst Non-albicans Candida, C.tropicalis was most common species isolated 21(50%)followed by C.parapsilosis ,11(26%),C.glabrata 5(12%),C.krusei 2(4.7%), C.tropicalis was predominant species isolated in blood 13/18(73%) followed by pus 9/12(75%).C. albicans predominanted in HVS 13/17(76%), sputum sample 4/6(67%), BAL 6/9 ( 66%),ETsecretion 2/3(67%). C.ciferrii was the only species isolated from ear discharge.

Interpretation and Conclusion: CHROM agar showed more sensitivity in detection of Candida albicans (100%) in comparison to CMA and VITEK 2 (97.4%)and decreased specificity (97.6%) as compared to CMA and Vitek-2  (100%) whereas for speciation of Non-albicans Candida particularly C.parapsilosis and C.glabrata CMA alone and also in combination with Vitek 2 exhibited much better sensitivity and specificity as compared to CHROM agar. Non albicans Candida showed higher level of resistance to azole group of drugs and were overall less sensitive to other antifungals as compared to C.albicans.So the amalgamation of cost effective Corn Meal Agar with CHROMAgar is an utmost need of an hour  to give accurate yeast identification  within same time span.