Antibiotic susceptibility and biofilm formation of bacterial isolates derived from pediatric patients with Cystic Fibrosis from Tehran, Iran

Document Type: Original Articles


1 Department of Microbiology, School of medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

2 Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran

3 Department of Microbiology, Medical School, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.

4 Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran


Cystic fibrosis (CF) is a genetic disease with the high rate of morbidity and mortality. Pediatric with CF commonly suffer from recurrent and persistent pulmonary tract infections caused by diverse bacterial pathogens. This study was conducted to investigate the prevalence, antimicrobial susceptibility and biofilm formation of bacterial isolates in pediatric patients with CF. This cross-sectional study was conducted on 8908 children suspected to have CF by clinical manifestations from March 2015 to August 2017 referred to the Tehran Pediatric Central Hospital Iran. The following investigations were carried out for each participant; screening sweat test, sputum culture, antibiotic susceptibility test using Kirby-Bauer disk diffusion method, and capacity of biofilm formation microtiter plate method. Based on clinical examination and screening sweat test, out of 8,908 children, 183 (2.05 %( were positive for CF with mean age of 2.93 years and gender distribution of 56.2% male (103) and 43.7% female (80). We found that there were no gender-specific differences in CF disease (P > 0.05). Results from sputum culture showed that, one hundred fifty-three (83.6%) microorganisms (bacteria and fungi) were collected from CF patients. In 30 (16.4%) patients normal flora were isolated and in 7.2% of patient’s more than one bacterial species were isolated. Pseudomonas aeruginosa was the most prevalent isolated bacteria followed by Staphylococcus aureus, and Klebsiella pneumoniae. According to antibiotic susceptibility test results, P. aeruginosa had the highest resistance rate against gentamicin (11.7%), and for piperacillin/tazobactam had the lowest rate (2.3%). However, all K. pneumoniae isolates were resistantce to Cefotaxime. Among S. aureus isolates, 83.4% and 16.6% were MSSA and MRSA respectively. Concerning biofilm formation, 76%, 67% and 72.5% of P. aeruginosa, S. aureus, and K. pneumoniae isolates were biofilm producer, respectively. Our study showed that P. aeruginosa was the dominant pathogen in pediatric patients with CF from Tehran, most of them were biofilm producer. Severe antibiotic resistance in our isolates was not being observed but, the anti-microbial resistance profile in CF patients should be carefully checked on a regular basis.