title: In Vitro Susceptibility and Trailing Growth Effect of Clinical Isolates of Candida Species to Azole Drugs.
abstract: BACKGROUND
  Emergence of resistance to respective antifungal drugs is a primary concern for the treatment of candidiasis. Hence, determining antifungal susceptibility of the isolated yeasts is of special importance for effective therapy. For this purpose, the clinical laboratory standard institute (CLSI) has introduced a broth microdilution method to determine minimum inhibitory concentration (MIC). However, the so-called "Trailing effect" phenomenon might sometimes pose ambiguity in the interpretation of the results.
  
  
  OBJECTIVE
  The present study aimed to determine the in vitro susceptibility of clinical isolates of Candida against azoles and the frequency of the Trailing effect.
  
  
  METHODS
  A total of 193 Candida isolates were prospectively collected and identified through the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Using a broth microdilution test, according to the guidelines of CLSI M27-A3, antifungal susceptibilities of the isolated yeasts against Fluconazole (FLU), Itraconazole (ITR), Ketoconazole (KET) and Voriconazole (VOR) were assessed. Moreover, trailing growth was determined when a susceptible MIC was incubated for 24 hours, and turned into a resistant one after 48 hours of incubation.
  
  
  RESULTS
  Among the tested antifungal drugs in this study, the highest rate of resistance was observed against ITR (28.5%) followed by VOR (26.4%), FLU (20.8%) and KET (1.5%). The trailing effect was induced in 27 isolates (14.0%) by VOR, in 26 isolates (13.5%) by ITR, in 24 isolates (12.4%) by FLU, and in 19 isolates (9.8%) by KET.
  
  
  CONCLUSIONS
  The monitoring of antifungal susceptibilities of Candida species isolated from clinical sources is highly recommended for the efficient management of patients. Moreover, the trailing effect should be taken into consideration once the interpretation of the results is intended.
authors.affiliation: Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran; Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors.forename: Kamiar
authors.initials: K
authors.lastname: Zomorodian
authors.affiliation: Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Bandegani
authors.affiliation: Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Mirhendi
authors.affiliation: Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran; Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors.forename: Keyvan
authors.initials: K
authors.lastname: Pakshir
authors.affiliation: Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors.forename: Navvab
authors.initials: N
authors.lastname: Alinejhad
authors.affiliation: Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Poostforoush Fard
keywords: Antifungal Susceptibility; Candida; Trailing Effect