Objective: Microorganisms that cause lung infections in cystic fibrosis (CF) are initially colonized in the upper respiratory tract mucosa and then pass into the lungs. In this study, we aimed to determine the pathogens colonized in the upper respiratory tract and the evaluation of phenotypic changes observed in these bacteria in patients with cystic fibrosis.

Methods: Between May 2016 and May 2017 the routine respiratory tract samples (throat swab or sputum) taken from the patients who were under follow-up with a previously diagnosed CF (Group I) or who were started to be followed up for a newly diagnosed CF (Group II) were evaluated in the Gaziantep University Şahinbey Research and Practice Hospital Pediatric Immunology and Allergy Outpatient Clinic. Conventional methods and Bruker MALDI Biotyper™ (Becton Dickinson, Sparks, MD, USA) automated system were used to identify bacteria.

Results: 500 respiratory tract samples from 123 patients were evaluated in the study. In 218 (43.6%) of the samples, 232 different pathogenic bacteria was isolated. 96 (18.3%) Staphylococcus aureus and 62 (11.8%) Pseudomonas aeruginosa were found as the most frequently isolated microorganisms. Phenotypic differences were detected in 16 S. aureus isolates as small colony variants and 24 P. aeruginosa isolates as mucoid colony producers. All of the isolates with phenotypic differences were isolated from patients in Group II.

Conclusions: In CF patients, depending on the prolongation of the disease duration, phenotypic changes misleading the immune system or escaping from it occur in bacteria that are colonize the respiratory tract. Detection of these changes may probe important in order to establish medical approaches to prevent colonization. Klimik Dergisi 2019; 32(2): 178-81.

Cite this article as: Büdeyri S, Zer Y, Keskin Ö, Bilgiç Ertan S. [Evaluation of phenotypic characteristics of microorganisms isolated from respiratory tract of the patients with cystic fibrosis]. Klimik Derg. 2019; 32(2): 178-81. Turkish.