MESHREF AWAD AL-RUWAILI, OMER MOHAMED KHALIL AND MUTAZ FATHELRAHMAN SAAD
Abstract
The existence of Candida species in different clinical specimens has increased significantly over the few last years due to various predisposing factors including prior antibiotic use, prolonged hospital stay, extremes of age, diabetes mellitus and the use of immunosuppressive therapy. The purpose of this study was to apply different diagnostic techniques for characterization of Candida species in different clinical samples at Aljouf area Saudi Arabia. A total of 250 specimens were collected from different body sites (115 samples of urine, 84 stools and 51 oral swabs). All specimens were obtained from outpatients seen at Al Quriat general Hospital, King Faisal Hospital and Prince Mutaeb hospital. Yeast isolates were purified on Sabouraud dextrose agar and then heavy suspensions were stored at -20 °C in 10% glycerol peptone water until use. To identify the isolates API 20 CAUX was used according to the manufacturer instructions. Forty Candida isolates were selected for DNA extraction, PCR and sequencing using ITS1 and ITS4 primers. The sequences generated were compared with data in the National Center for Biotechnology Information database using the basic local alignment search tool (BLASTn; http://www.ncbi.nlm.nih.gov/). 97 Yeast isolates were recovered, 62 isolates (54%) in urine, 23 (19.6%) in stool and 12 (6.1%) in oral swabs. Out of the 97 yeast only 38 Candida isolates were recovered using API 20 CAUX. The phylogenetic relationships tree of the tested isolates showed the possibility of new C. tropicalis clade compared to the C. tropicalis type strain. Most of other similar species were found to be closer to each other.