جداسازي كريپتوكوكوس نيوفورمنس واريته گتي از درختان اكاليپتوس كامالدولنسيس

Study of Cryptococcus neoformans var.gattii from Eucalyptus camaldulensis in some northern regions of Iran

Introduction: So far Eucalyptus camaldulensis is the only known environmental source of Cryptococcus neoformans var.gattii in Australia. Based upon the hypothesis that Australian origin E.camaldulensis trees could be a natural habitat for the C.neoformans var.gattii in Iran as well, this study was performed on 380 E.camaldulensis. Materials and Methods: Trees grown and located in Garmsar, Gonbade Natural sources training center and Sadd-e- Ghaboos. Over a period of 23 months samples of stem bark (380), flowers (300) and fruits(80) were obtained. The supernatants of the sample suspensions were inoculated onto sabouraud dextrose agar and niger seed agar, incubated at 30°C for 7 days. The identity of 138 isolates which produced blastoconidia on cornmeal agar supplemented with tween-80 based on the results obtained from using a battrey of morphological, biochemical and physiological tests including staining by lactophenol cotton blue and India ink technique, urease production and assimilation tests by API 20c Aux. Finally, canavanin glycine bromotymol blue (GCB) and glycine cyclohexamid phenol red (GCP) were used to distinguish C.neoformans varieties. Results: Overall, 2 of isolates (one from Garmsar and the other from Sadd-e- Ghaboos Voshmgir) were found to be C.neoformans var.gattii and 43 of isolates determined C.albidus and 36 of isolates determined C.laurentii and 57 of isolates determined C.sp. Niger seed agar containing 0.1% glucose is used for rapid melanin production, consequently C.neoformans produced dark-brown colonies and most strains of C.laurentii turned niger seed agar to green and a few C.SP turned niger seed agar to blue. Also 3 isolates of Hendersonula toruloidea were recovered from the Gonbade natural sources training center. Conclusion: The results show that australian origin E.camaldulensis trees could be a natural habitat for the C.neoformans var.gattii and this study also showed that GCB medium serves as an excellent total for the sepration of the two varieties of C.neoformans, but it is not useful in detection of C.neoformans from C.laurentii.