Etiologic agents of dermatophyte infection in Lebanon.

BACKGROUND: Dermatophytes are common and cause important human fungal infections in many parts of the world, including Lebanon. The prevalence of these fungi, however, tends to vary with time and geographic location. In our region, studies on the prevalence of dermatophytoses and the distribution of the various dermatophyte species involved are rare. In Lebanon, only one study was published on this subject over the last forty years.

OBJECTIVES: This study was undertaken to shed light on the types and prevalence of dermatophytes recovered at the American University of Beirut Medical Center (AUBMC), and to compare the findings with those of the only study from the same hospital published in the early 1960s.

METHODS: Records from the clinical microbiology section were reviewed for the patients on whom dermatophyte cultures were requested between 1996 and 2002. All positive cultures were identified and analyzed.

RESULTS: Among 1631 submitted specimens for culture (one per patient), 208 (12.7%) yielded 11 species of dermatophytes, dominated by Trichophyton spp. (89.9%), followed by Microsporum spp. (9.1%), Epidermophyton floccosum (0.4%) and Trichosporum beigelii (0.4%). The male to female ratio was almost 1:1, and the age range was 1 to 77 yrs for both sexes; 14% were children (< or = 15 yrs). The most commonly recovered species were: T. tonsurans (54.8%), T. mentagrophytes (24.5%), M. canis (7.7%), T. rubrum (5.3%) and T. verrucosum (4%). The distribution of infection according to body sites was : tinea unguium (44.2%), tinea corporis (43.2%), tinea capitis (7.7%) and tinea pedis (4.8%). Compared to the previous study from AUBMC in 1962, the current study showed an overall lower prevalence of dermatophytoses (12.7 vs 18.5%, p = 0.001) and variations in the prevalence rates of the dermatophyte species involved (dominated by T. tonsurans and T. mentagrophytes in the current study compared to E. floccosum and T. rubrum recovered in 1962). Based on the source of infection the current study showed higher transmission from human to human (anthropophylic) (86.5 vs 66.3%) and animal to human (zoophylic) (12.5 vs 1.1 %), but lower transmission from soil to human (geophylic) (1% vs 32.6%).

CONCLUSIONS: The prevalence of dermatophytoses remains high in this country. The recognition of the changing prevalence in the causative dermatophyte species should help with the treatment approach and for potential implementation of control measures.