Susceptibility profile of Candida spp. isolated from humans and dogs with stomatitis to the essential oil of Thymus vulgaris

Abstract

Candida spp. form a part of human and animal oral cavity flora. However Candida spp. is the main cause of dental related stomatitis in humans and stomatitis in dogs. Stomatitis treatment implies the use of azoles and polyenes to which yeasts build up resistance. The research is directed to the use of natural compounds such as essential oils. The aim of this paper is to define the antifungal activity of thyme oil on 15 clinical strains of Candida spp., isolated from humans and dogs and to determine if there is a difference in susceptibility between human and dog isolates. Sampling in patients with stomatitis was done by swabbing the denture or oral mucosa swab while sampling in dogs was done by swabbing the oral cavity mucosa after stomatitis has been diagnosed. In order to investigate the antifungal activity of thyme oil in vitro, microdilution method was used. Thyme oil expressed antifungal effects on all investigated strains. Also, our data show that the values of minimum fungicide concentration (MFC) and minimum inhibitory concentration (MIC) are lower in human strains. Explanation is that in most cases, stomatitis in humans is asymptomatic and thus not treated, so Candida strains have not developed resistance. On the other hand, stomatitis in dogs is followed by a marked clinical picture and treated is by antimicotics (mostly by azoles), therefore resistant Candida strains are more likely to occur.

Candida spp. je sastavni deo mikrobioma usne duplje čoveka i psa. Međutim Candida spp. predstavlja glavni uzročnik proteznog stomatitisa kod čoveka i stomatitisa kod psa. Terapija stomatitisa podrazumeva korišćenje azola i poliena na koje poslednjih godina gljivice razvijaju otpornost. Istrživanja se usmeravaju ka primeni prirodnih preparata kao što su etarska ulja. Cilj rada je utvrdi antifungalnu aktivnost ulja timijana na kliničke izolate Candida spp. čoveka i psa, i utvrdi da li postoji razlika u osetljivosti sojeva Candide spp. izolovanih kod čoveka i psa. Uzorkovanje kod pacijenata sa stomatitisom je vršeno brisom proteze ili brisom sluzokože. Kod pasa je uzrokovanje vršeno brisom sluzokože usne duplje kada je dijagnostikovan stomatitis. Zasejani sojevi su in vitro tretirani korišćenjem mikrodilucione metode da bi se utvrdilo da li ulje timijana deluje na kliničke izolate Candida spp. čoveka i psa. Rezultati pokazuju da su vrednosti minimalne fungicidne koncentracije (MFC) i minimalne inhibitorne koncentracije (MIC) manje kod čoveka. Stomatitis je kod ljudi najčešće je asimptomatski, pacijenti se ne podvrgavaju lečenju, pa sojevi Candida spp. nisu razvili rezistenciju na antifungicidne preparate. Kod pasa stomatitis je praćen burnijom kliničkom slikom, leči se antimikoticima (uglavnom azolima) pa je verovatnoća pojave rezistentnih sojeva Candida spp. veća.