Effects of different sample processing protocols on dermatophyte culture yield: A comparative study

Authors : Jaswinder Singh Gill, Jaswinder Singh Gill, Sourav Sen, Sourav Sen, Ashwini Agarwal, Ashwini Agarwal

DOI : 10.18231/2394-5478.2018.0110

Volume : 5

Issue : 4

Year : 0

Page No : 543-547

Introduction: Dermatophytes fungi infect keratinized tissues such as hair, nails and skin. Different methods for sample collection and transportation of dermatophytes for culture have been described. The standard methods for dermatophytes sample collection, transportation and lab processing, results in low positive culture dermatophyte yield. In this study, we have compared the standard method (Protocol A) with modified sample processing protocol (Protocol B), developed by our department. This modification was based on the core concept of collection, inoculation, starting incubation and transportation of dermatophyte sample, at patient’s point of care.
Materials and Methods: A total of 200 clinical isolates of dermatophytes, were subjected to two different sample processing protocols. Standard method was Protocol A and laboratory developed method was labelled as Protocol B. Protocol B, included a small (7ml) transparent plastic tube with special culture media. These tubes were inoculated with sample at patient’s point of care and same tube were utilized as transportation media.
Results: Samples processed as per modified protocol (Protocol B), demonstrated positive dermatophyte culture yield in 160 out of 200 samples, whereas figures were 80 out of 200 for samples processed as per standard protocol (Protocol A). Difference in positive dermatophyte culture yields, were statistically significant. The contamination rates of dermatophyte culture by saprophytic fungus and bacteria, was measured, 6% for Protocol A and 1% for Protocol B.
Conclusion: Our study demonstrated that a simple, economical modification in the procedure for dermatophyte sample processing by the laboratory, has led to a significant increase the positive dermatophyte culture yield with reduced secondary contamination rates.

Keywords: Dermatophytes, Sabouraud dextrose agar, Fungal culture, Contamination.


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