Prevalence and antibiotic resistance of bacterial pathogens in respiratory tract samples of geriatric patients

Abstract

Background/Aim: The frequency and severity of respiratory tract infections increase with aging. The aim of this study was to determine the bacterial profile of respiratory tract samples in geriatric patients and evaluate the antibiotic susceptibility patterns of the pathogens. Methods: In this cross-sectional study, a total of 509 clinical samples which were obtained from 302 geriatric patients over 65 years of age and sent to the microbiology laboratory between June 2019-January 2021 were investigated retrospectively. The identification and antibiotic susceptibilities of strains were evaluated with BD-Phoenix-100 fully automated microbiology system. Results: Of the 302 geriatric patients, 166 (%55) were males and 136 (%45) were females. The most isolated pathogens were Klebsiella pneumoniae (25.3%) Pseudomonas aeruginosa (22.5%) and Acinetobacter baumannii (10.2%), Corynebacterium striatum (7.3%), Escherichia coli (6.4%), Staphylococcus aureus (6.4%) and coagulase-negative staphylococci (4.2%). The production of ESBL in Klebsiella pneumoniae strains (52.3%) was higher than in Escherichia coli (41%) strains. All Corynebacterium striatum samples were resistant to ciprofloxacin, tetracycline, rifampin, and penicillin. Methicillin resistance among Staphylococcus aureus (MRSA) isolates was 22.7% and they were 100% susceptible to vancomycin and teicoplanin. Above 90% of K. pneumoniae, P. aeruginosa and A. baumannii positive patients were hospitalized in intensive care units (P<0.05). The tobramycin-resistant E. coli and colistin-resistant A. baumannii rates were highest between 85-99 years of age (P<0.05). Conclusion: K. pneumoniae, P. aeruginosa and A. baumannii were the most common pathogens in respiratory tract samples in geriatric patients, especially those hospitalized in the intensive care units. The antimicrobial resistance rates were higher in patients aged ≥85 years. Vancomycin and teicoplanin were the most effective antibiotics against MRSA. It is thought that the results will be useful in the preparation of treatment protocols and guiding physicians about the correct use of antibiotics.