Which organism exhibits fluorescence under ultraviolet light?

Which organism exhibits fluorescence under ultraviolet light?

• A. Microsporum gypseum
• B. Trichophyton mentagrophytes
• C. Microsporum canis
• D. Epidermophyton floccosum

Answer: (C)

Under ultraviolet light, certain dermatophytes produce a characteristic glow due to pigment production; Microsporum canis is the classic example that gives a bright apple-green fluorescence on affected hair and skin. This reliable glow helps distinguish it from other dermatophytes, which typically do not fluoresce or do so only inconsistently. Epidermophyton floccosum and Trichophyton mentagrophytes are generally non-fluorescent under Wood’s lamp, while Microsporum gypseum may show little or variable fluorescence. So the organism that exhibits fluorescence under ultraviolet light most consistently is Microsporum canis.

Under ultraviolet light, certain dermatophytes produce a characteristic glow due to pigment production; Microsporum canis is the classic example that gives a bright apple-green fluorescence on affected hair and skin. This reliable glow helps distinguish it from other dermatophytes, which typically do not fluoresce or do so only inconsistently. Epidermophyton floccosum and Trichophyton mentagrophytes are generally non-fluorescent under Wood’s lamp, while Microsporum gypseum may show little or variable fluorescence. So the organism that exhibits fluorescence under ultraviolet light most consistently is Microsporum canis.