The investigation of genotyping differences between infecting and colonizing Candida albicans strains by pulsed field gel electrophoresis and arbitrarily primed PCR methods

.100- SUMMARY Although the clinical importance of fungal infections is well known there is limited knowledge about the colonization with the fungi, pathogenesis of infection, route of transmission and the epidemiology. Molecular typing methods are important for evaluating of Candida infections. The aim of our study is to search the genotypic relation between C. albicans strains isolated as infection agents and to search the origin of infection is either exogenous and endogenous. Another aim of this study is to search clonal relation between fluconasole resistant and susceptible strains. 51 C. albicans strains isolated from haematology-oncology patients and 32 colonization strains that are not accepted as infecting agents were taken into this study. We used AP-PCR and PFGE-EK analysing methods for molecular typing of C. albicans. 51 strains taken from Haematology-Oncology patients revealed 24 different genotypes by AP-PCR and 45 genotypes by PFGE-EK. 32 colonization strains isolated from intense care units revealed 16 genotypes by AP- PCR and 28 genotypes by PFGE-EK. Discrimination indexes for both of the methods were high, but PFGE-EK identified more genotypes than AP-PCR. After the molecular typing of infecting strains we realized that these infection were endogenous. Besides, findings about cross transmission were noted. We colected environmental materials and materials from health workers in order to detect the origin of exogenous tranmission and cross transmission but any C. albicans strain was not isolated.-101- We could not find any clonaly related or dominant genotype between fluconasole resistant or susceptible strains with the molecular typing methods we used. As a result, AP-PCR and PFGE-EK analysing methods are found successful methods for the molecular typing of C. albicans strains. We determined that most of the infections originated from the endogen flora but cross transmission between patient to patient or health workers to patients could also be possible.