[Survey the role of temperature, pH and the glucose concentration on in vitro germ tube formation by Candida dubliniensis]

ABSTRACT

C. dubliniensis is a new known species in genus of Candida. Although this yeast was firstly isolated from oral lesions in AIDS patients, but recently it has been isolated from non-AIDS immunosupressed lesions as well. The ability of C. dubliniensis in production of germ tube in human serum is one of the most important virulent factors, which can induce transformation of fungi from yeast to filamentous form. This phenomenon can be altered by few environmental and nutritional factors. The general purpose of this study was to investigate the effect of temperature, pH and glucose concentrations in germ tube formation of C. dubliniensis in in vitro. The germ tube production test in human serum [with normal glucose titer] in different temperature, pH, and glucose concentrations were conducted using standard strain of C. dubliniensis [CD 34]. The average number of cells with germ tube after 2 hours and the earliest time for production of germ tube were analyzed using one-way ANOVA test. Maximum germ tube production rate were seen in 42°C, pH 7 and in concentration of 30 mg/ml glucose [P= 0.0001] and also germ tube observed in earliest time in those conditions. It seems that these environmental and nutritional factors in human body can promote this fungus to produce germ tube for invasion in susceptible patients especially in diabetics