# Refining a low-cost dermatophyte sampling method to enhance culture purity in resource-limited clinical settings in Bangladesh

## TL;DR

This study evaluates low-cost methods to improve the purity of dermatophyte cultures in resource-limited settings, finding a paper-zip transport approach to be most effective.

## Contribution

The study introduces and validates low-cost, practical sampling methods to enhance dermatophyte culture purity in resource-limited settings.

## Key findings

- The Paper-Zip method showed the highest selectivity for pure dermatophyte isolates with reduced contamination.
- Diagnostic sensitivity remained consistent across all sampling approaches.
- The methods are practical and low-cost for routine use in resource-limited clinical settings.

## Abstract

Dermatophytosis is an emerging public health concern in developing countries, with rising infection rates and persistent disease burden. Reliable isolation of dermatophytes is essential for effective treatment, surveillance, and downstream analyses, yet it remains challenging in low-resource clinical settings. We evaluated three mycological sampling approaches, including one conventional and two modified techniques to improve the recovery of pure dermatophytes while reducing contamination. The modified approaches comprised a heat-assisted aseptic sampling method to limit airborne contamination and a paper-zip transport approach using heat and sterile filter paper sealed in zip-lock bags before inoculation into the culture medium. The outcomes of all sampling approaches were subsequently assessed using conventional culture techniques. A total of 198 clinical specimens from 66 individuals generated 276 culture outcomes. Statistical analysis showed significant differences among methods in recovery of pure isolates and contamination control, with the Paper-Zip method exhibiting the highest selectivity (p < 0.05). Sensitivity analysis using conventional culture techniques showed similar diagnostic performance across the approaches, reflecting improvements in dermatophytes recovery.

Heat-assisted and Paper-Zip sampling improve recovery of pure dermatophytes while minimizing contamination.

Diagnostic sensitivity is consistent across all sampling approaches.

The study demonstrates practical, low-cost implementable options for routine diagnostics in resource-limited clinical settings.

Image, graphical abstract