Abstract

Background: Multidrug-resistant (MDR) Klebsiella pneumoniae is an emerging cause of severe pneumonia in Southeast Asia. However, data on MDR K. pneumoniae in elderly patients with community-acquired pneumonia (CAP) remain limited. Objective: To determine MDR K. pneumoniae prevalence among elderly CAP patients, identify risk factors, and evaluate resistance to empiric antibiotics. Methods: A prospective cohort study was conducted at a tertiary geriatric hospital in Vietnam from January 2023 to June 2024. We analyzed a subgroup of 181 patients aged ≥ 60 years with culture-confirmed K. pneumoniae CAP. Results: The median age was 81 years. The prevalence of MDR K. pneumoniae was 26.5% (48/181). Resistance rates to first-line empiric agents were high: ciprofloxacin (50.6%), levofloxacin (30.0%), ceftazidime (38.7%), and ceftriaxone (31.1%). Amikacin remained highly effective (1.5% resistance). In univariable analysis, Chronic Obstructive Pulmonary Disease (COPD) (OR 2.16; 95% CI 1.03–4.53; p = 0.039), prior intravenous antibiotic use within 90 days (OR 3.32; 95% CI 1.49–7.42; p = 0.002), and hospitalization within the preceding 30 days (OR 2.28; 95% CI 0.99–5.21; p = 0.048) were associated with MDR K. pneumoniae. In the multivariable model, prior intravenous antibiotic use within 90 days (OR 3.00; 95% CI 1.32–6.80; p = 0.009) was identified as the independent risk factor for MDR acquisition. Conclusion: A substantial proportion of elderly CAP patients harbor MDR K. pneumoniae at admission. Given high resistance to fluoroquinolones and cephalosporins, empiric guidelines require re-evaluation for patients with recent intravenous antibiotic exposure.

Key words: Klebsiella pneumoniae; Community-acquired pneumonia; Multidrug resistance; Aged; Antibiotic stewardship.