Evaluation of pathogens and antibiotic resistance profiles isolated from lower respiratory tract samples

Abstract

Objective: In this study, we aimed to guide clinicians in planning empirical treatment and contribute to regional data by presenting bacterial lower respiratory tract infection agents and antibiotic resistance profiles. Methods: All lower respiratory tract samples from patients admitted to our laboratory between January 01 and December 31, 2021 were evaluated retrospectively. Bacterial identification and susceptibility tests were performed using the VITEK 2 automated system and evaluated in accordance with the recommendations of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Results: Significant growth was detected in 461 of 923 lower respiratory tract samples. Antibiotic susceptibility test results of 340 samples were evaluated after excluding the repeated samples of same patient. Gram negative bacteria was isolated in 309 (90.9%), Staphylococcus aureus in 17 (5%) and Candida albicans in 14 (4.1%) of 340 samples. The most frequently isolated Gram-negative bacteria were Pseudomonas aeruginosa (121, 39.2%), Acinetobacter baumannii (88, 28.5%), Klebsiella pneumoniae (64, 20.7%) and Escherichia coli (36, 11.6%), respectively. Resistance rates of A. baumannii isolates to carbapenems, piperacillin/tazobactam, ceftazidime and fluoroquinolones were found to be over 90%, and higher resistance was observed in intensive care units (ICU) than in wards. Conclusion: The increased antibiotic resistance observed in lower respiratory tract infections from hospitalized patients in ICUs, is remarkable. As a result, knowing the causative agents and current resistance profiles is important, especially for hospitalized patients in ICUs, in order to initiate appropriate empirical treatment and to ensure treatment success. The data obtained from our study will guide clinicians in planning empirical treatment.