Genotypic characterisation of Pseudomonas aeruginosa isolates from Turkish children with cystic fibrosis Dicle Sener Okur,1 Caner Yuruyen,2 Ozge Gungor,2 Zerrin Aktas,2 Zayre Erturan,2 Necla Akcakaya,3 Yildiz Camcioglu,3 Haluk Cokugras,3 Kaya Koksalan41Istanbul University Cerrahpasa, Faculty of Medicine, Department of Pediatrics, Division of Pediatric Infectious Diseases, 34098 Kocamustafapasa, Istanbul, Turkey; 2Istanbul University Istanbul, Faculty of Medicine, Department of Microbiology and Clinical Microbiology, 34390 Capa, Istanbul, Turkey; 3Istanbul University Cerrahpasa, Faculty of Medicine, Department of Pediatrics, Division of Pediatric Infectious Diseases, Clinical Immunology and Allergy, 34098 Kocamustafapasa, Istanbul, Turkey; 4Istanbul University, Institute for Medical Experimental Research (DETAE), 34390 Capa, Istanbul, TurkeyObjective: To identify epidemic and other transmissible Pseudomonas aeruginosa strains, genotypic analyses are required. The aim of this study was to assess the distribution of P. aeruginosa strains within the Turkish pediatric cystic fibrosis (CF) clinic population.Methods: Eighteen patients attending the pediatric CF clinic of Cerrahpasa Medical Faculty were investigated in the study. Throat swab and/or sputum samples were taken from each patient at 3-month intervals. The isolates of patients were analyzed by pulsed-field gel electrophoresis (PFGE). The intra- and interpatient genotypic heterogeneity of isolates was examined to determine the clonal isolates of P. aeruginosa within the cohort.Results: A total of 108 clinical isolates of P. aeruginosa were obtained from 18 patients between May 2013 and May 2014. The pulsotypes of the first patient’s isolates could not be obtained by PFGE. From the remaining 17 patients and 101 isolates, 55 distinct pulsotypes were detected. The number of pulsotypes observed in more than one patient (minor clonal strains, cluster strains) was 8 (14.5%), and one of them colonized three patients. However, none of them was detected in more than three patients. These pulsotypes were composed of 20 isolates. In addition, with the PFGE analysis of 81 isolates, we detected 47 (85.6%) pulsotypes, which belonged to only one patient. Over different periods of this study, only 2 (11.8%) patients were colonized with the same pulsotype.Conclusion: Our study indicates that there was considerable genomic diversity among the P. aeruginosa isolates in our clinic. The presence of shared pulsotypes supports cross-transmission between patients.Keywords: P. aeruginosa, cystic fibrosis, PFGE, genotype, phenotype, epidemiology