Dalmau Plate Technique: Cherished In Memory

The Dalmau plate test is a classic mycological technique used for the identification and differentiation of yeast species based on their morphological features. The test involves the use of a specific medium that promotes the formation of specific structures, which are then examined microscopically to determine the yeast species.

A light inoculum of yeast from pure colony culture is streaked onto the surface of cornmeal agar often supplemented with Tween 80, then a coverslip is placed over the inoculated area. Following an incubation period of around 48 hours at 22 to 26°C, the plate is examined beneath a coverslip to identify important features such as pseudohyphae, blastoconidia, and chlamydospores.

Although this technique has significant limitations, it is a valuable and simple method for the preliminary identification of Candida species, particularly those that produce chlamydospores, such as Candida albicans. Clinical laboratories use a variety of methods to identify different species of Candida isolates now a days. These include commercial, automated, kit-based, traditional and molecular techniques like PCR. But each method has its own merits and demerits. Hence, clinical laboratories must use a reliable and feasible method for accurately identifying the Candida species to start prompt and appropriate antifungal therapy.

In clinical settings, the Dalmau plate is one of the procedures that works best when combined with more advanced approaches for thorough identification. However, in the current environment, when accurate and timely diagnosis is essential, this method is only treasured in memories.

References

1. Bhaskaran R, Valsan C, A SK. Evaluation of the four phenotypic methods for the speciation of Candida isolates in comparison with molecular method. Indian J Microbiol Res. 2020;7(2):168-174.

2. Yazdanpanah A, Khaithir TM. Issues in identifying germ tube positive yeasts by conventional methods. J Clin Lab Anal. 2014;28(1):1-9.

3. Deorukhkar SC, Roushani S.Identification of Candida Species: Conventional Methods in the Era of Molecular Diagnosis. Ann Microbiol Immunol. 2018; 1(1): 1002.

4. Bhattacharyya S. Laboratory diagnostic methods for medically important fungi. IP Int J Med Microbiol Trop Dis. 2022;8(3):179-182.

5. Evren E, Göçmen JS, İştar EH, et al. Medically important Candida spp. identification: an era beyond traditional methods. Turk J Med Sci. 2022;52(3):834-840.

6. Koehler AP, Chu KC, Houang ET, Cheng AF. Simple, reliable, and cost-effective yeast identification scheme for the clinical laboratory. J Clin Microbiol. 1999;37(2):422-426.

7. Yahaya, Ibrahim, Sharif. Candida diagnostic platforms: essential in early management of candida infections. FUDMA Journal of Sciences (FJS) 2021;5(2): 59 – 71.