What is the indicator of dermatophyte test medium?

The medium contains phenol red as a pH indicator. If a dermatophyte is present, characteristic colony morphology will be observed and the medium underlying the colonies will turn red.

How do you test for dermatophytes?

Dermatophyte infections can be readily diagnosed based on the history, physical examination, and potassium hydroxide (KOH) microscopy. Diagnosis occasionally requires Wood’s lamp examination and fungal culture or histologic examination. Topical therapy is used for most dermatophyte infections.

How do the ingredients in dermatophyte test medium work to detect dermatophytes growing in it?

Dermatophyte test medium (DTM) is a specialized agar used in medical mycology. It is based on Sabouraud’s dextrose agar with added cycloheximide to inhibit saprotrophic growth, antibiotic to inhibit bacterial growth, and phenol red a pH indicator.

How do you prepare dermatophyte agar?

Methods of inoculation and incubation Make sure the agar surface is dry. Place the sample centrally on the surface of the medium and press it gently to ensure firm contact. Allow the cap on the tube to remain loose to ensure gaseous exchange during incubation. Incubate at 25°C for up to 2 weeks in ambient air.

How do you read a DTM?

In addition to observing for a red color change, the interpretation of DTM growth should include an assessment of gross and microscopic colony morphology. Dermatophytes grown on DTM are generally lightly pigmented (white, buff, tan or cinnamon-colored), whereas common saprophytes are often darkly pigmented.

How do you prepare Dermatophyte agar?

How does a DTM culture work?

The DTM incorporates antibiotics (gentamicin and chlortetracycline) to suppress bacterial growth, cycloheximide to suppress saprophytic fungal growth, and phenol red as a color indicator. It provides both carbohydrate and protein nutrients.

Which type of media would you use when conducting a direct examination of fungi on a microscope slide?

The media most commonly used are nutrient agar (bacteria), potato dextrose agar (fungi), and Sabouraud dextrose agar (fungi).

What are the three dermatophytes?

There are three genera of dermatophytes, Trichophyton, Microsporum, and Epidermophyton.

How long is dermatophyte culture?

In general, it is recommended to incubate dermatophytes cultures for a minimum of 4 weeks. Several aspects of routine fungal cultures should be evaluated in order to implement appropriate and necessary changes.

What stain is used for microscopic examination of a dermatophyte?

Chicago sky blue stain
Using Chicago sky blue stain, dermatophytes were detected easily at ×100 magnification as blue stained fungal hyphae against the purple to pink cellular background and were confirmed by observation at ×400 magnification to visualize septate filaments.