Objective: The morbidity and mortality associated with the community-acquired and nosocomial respiratory tract infections (RTIs) pose a significant and growing challenge to clinical practitioners. The aim of this retrospective study was to determine the etiologic agents in patients with RTIs in Başkent University Adana Hospital and to evaluate their antimicrobial resistances.

Methods: Sputum and trans tracheal aspirate (TTA) cultures from April 2016 to May 2018 were evaluated. Conventional methods and an automatized microbiological system were used for the identification and the antimicrobial susceptibility tests were performed according to the CLSI 2016 standards.

Results: A total of 641 bacterial pathogens were isolated from 245 sputum and 396 TTA cultures of 442 patients. Most prevalent isolates were, Acinetobacter baumannii (25%), Pseudomonas aeruginosa (12.6%), Klebsiella spp. (14.7%), Escherichia coli (10%), Haemophilus influenzae (6.9%), Staphylococcus aureus (5.5%) and Streptococcus pneumoniae (5.1%). More than one agent was isolated from 116 patients (26.2%). Overall 80.6% of A. baumannii, 86.5% of P. aeruginosa and 79.5% of Klebsiella pneumoniae isolates were recovered from the intensive care unit patients.

Conclusion: In conclusion, the increase in resistance rates of respiratory tract infection isolates was found to be remarkable. The high resistance rates to all antibiotic groups of the predominant isolates A. baumannii and K. pneumoniae are worrying. It is necessary to perform studies showing the distribution and resistance pattern of such microorganisms isolated from patient with RTIs at certain time intervals for correct antibiotic use. The results are thought to be useful for updating empirical treatment protocols and guiding clinicians on the correct use of antibiotics.