Risk Factors and Mortality of Elderly Patients with Hospital-Acquired Pneumonia of Carbapenem-Resistant Klebsiella pneumoniae Infection

Risk Factors and Outcomes of Community-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection in Elderly Patients

The increasing prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) infections is a global concern. Elderly patients have a diminished immune response and functional reserve, and are thus more vulnerable to bacterial infection. This study aimed to investigate the risk factors and outcomes in elderly patients with community-acquired CRKP infections. We performed a retrospective cohort study in a tertiary medical center between 1 January 2021, and 31 December 2021. All elderly patients who visited the emergency department during this period with culture-positive K. pneumoniae were enrolled, and their baseline demographics, laboratory profiles, management strategies, and outcomes were recorded and analyzed. We identified 528 elderly patients with K. pneumonia infection, and the proportion of patients with CRKP infection was 10.2% (54/528). Recent intensive care unit (ICU) admission and prior carbapenem use are independent risk factors for CRKP infection in elderly patients. Compared to patients with carbapenem-sensitive K. pneumoniae infection, those with CRKP infection had a significantly higher risk of adverse outcomes, including ICU care, respiratory failure, septic shock, and 90-day mortality. CRKP infection was also identified as an independent risk factor for 90-day mortality. Clinicians should be aware of the increasing prevalence of CRKP infections in elderly patients and judiciously choose appropriate antibiotics for these patients.

Clinical and Microbiological Risk Factors for 30-Day Mortality of Bloodstream Infections Caused by OXA-48-Producing Klebsiella pneumoniae

Bloodstream infections (BSI) caused by carbapenem-resistant Klebsiella pneumoniae are associated with high morbidity and mortality, and the therapy options available for their treatment are frequently scarce. The aim of this study was to analyze risk factors for 30-day mortality in patients with BSI caused by OXA-48-producing K. pneumoniae. The clinical and treatment features of the patients, who attended a single hospital over a five-year period, were retrospectively reviewed. The microbiological features, including the sequence types (ST) and the somatic (O) and capsular (K) antigens, as well as their resistance properties, comprising phenotypes and genetic background, were also considered. To identify the risk factors for 30-day mortality, uni- and multivariate statistical analyses were performed. The univariate analysis revealed statistically significant correlations for age, male gender, lower respiratory system infection, infection by ST147 isolates, and infection by isolates expressing the K64 antigen. The multivariate analysis, applied to variables yielding p-values close to or lower than 0.05 in the univariate analysis, confirmed gender, lower respiratory system infection, and infection with ST147 isolates, but not age or infection with K64 isolates, as risk factors for 30-day mortality. Moreover, the multivariate analysis showed that patients suffering from hematological malignancies or having been treated with inappropriate therapy, both having p-values slightly higher than 0.05 in the univariate analysis, exhibited significantly poorer outcomes in the multivariant analysis. The association of the ST147 clone with an increased risk of mortality is a novel finding that deserves further attention. Studies like the one presented here can certainly benefit the management of patients with nosocomial BSI caused by carbapenemase-producing K. pneumoniae.