Shahroud University of Medical siences Shahroud Journal of Medical Sciences 2423-6594 12 4 2026 08 09 Isolation and Characterisation of Microbial Pathogens From Cystic Fibrosis Patients in Southeastern Iran 51 56 eng Zakaria Bameri Infectious Diseases and Tropical Medicine Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran.. mojdehjahantigh001@gmail.com Abolfazl Parsi Moud Student Research Committee, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.. mojdehjahantigh001@gmail.com Mojgan Jahantigh Department of Community Nursing, Nursing Research Center, School of Nursing and Midwifery, Zahedan University of Medical Sciences, Zahedan, Iran.. mojdehjahantigh001@gmail.com Mojdeh Jahantigh Cellular and Molecular Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran.. mojdehjahantigh001@gmail.com 2025 06 16 2025 11 02 Background: Cystic fibrosis (CF) is a genetic disorder that leads to severe respiratory complications primarily due to recurrent lung infections. This study aimed to isolate and identify microbial pathogens from the respiratory secretions of CF patients and investigate factors influencing their virulence and antibiotic resistance. Methods: In this cross-sectional study conducted between 2021 and 2024, 45 confirmed CF samples were collected from throat samples at Aliebne Abitaleb Hospital in Zahedan, Iran. Following the identification of the strains, their antibiotic resistance was assessed by the disk diffusion method based on the Clinical Laboratory Standards Institute 2022. Also, the formation of biofilm was investigated by using a crystal violet assay, and relevant genes were identified by the PCR method. Results: The results revealed a high prevalence of Pseudomonas aeruginosa and Staphylococcus aureus, 24.4% and 35.6%, respectively, with significant rates of multidrug resistance observed among these pathogens. Notably, biofilm formation was identified as a critical factor contributing to antibiotic resistance, complicating treatment options. Conclusion: These findings underscore the need for tailored antibiotic strategies and highlight the importance of ongoing surveillance of microbial pathogens in CF patients to inform clinical practices.