In vitro Activity of Eravacycline and Risk Factors for Carbapenem- Resistant Klebsiella Pneumoniae Infections in Patients with Respiratory Diseases: A Retrospective Cohort Study

Background Carbapenem-resistant Klebsiella Pneumoniae (CRKP) infections pose a significant threat to patients with respiratory diseases, resulting in prolonged hospital stays, increased mortality rates, and substantial healthcare costs. Although tigecycline (TGC) is a therapeutic option, concerns regarding its efficacy and safety continue to persist. Eravacycline (ERV), a novel fluorocycline, exhibits potent in vitro activity against multidrug-resistant Gram-negative pathogens, potentially serving as a valuable alternative. However, comparative data on the efficacy of ERV against CRKP isolates from respiratory and non-respiratory sources, as well as the identification of infection-specific risk factors, remain limited. Methods A retrospective cohort analysis was conducted on 1,604 CRKP isolates collected from clinical specimens at Shaanxi Provincial People’s Hospital between January 2020 and October 2025. The isolates were categorized into two groups: respiratory disease (n = 1,048) and non-respiratory disease (n = 556). Bacterial identification and antimicrobial susceptibility testing were performed using automated systems (BD Phoenix™) and E-test strips, with results interpreted according to CLSI 2021 guidelines. Multivariable logistic regression was utilized to identify independent risk factors associated with infection acquisition and poor prognosis. Results The respiratory disease group exhibited a significantly higher resistance rate to meropenem ( P  = 0.001). Both ERV and tigecycline maintained high activity against CRKP; however, ERV demonstrated superior in vitro susceptibility compared to TGC in both respiratory ( P  < 0.001) and non-respiratory ( P  < 0.001) isolates. Multivariable analysis identified invasive procedures (drainage tube: OR = 1.53, P  = 0.027; PICC: OR = 1.57, P  = 0.022), advanced age (OR = 1.07 per year, P  < 0.001), and chronic kidney disease (OR = 2.89, P  = 0.027) as independent risk factors for mortality. Elevated levels of serum globulin and serum amyloid A (SAA) were significantly associated with the respiratory disease group ( P  < 0.01). ICU admission (OR = 17.44, P  < 0.001) and endotracheal intubation (OR = 5.14, P  < 0.001) were strong predictors of fatal outcomes. Conclusion This study highlights the distinct resistance profile and prognostic determinants of CRKP infections in patients with respiratory diseases. The extended-release vancomycin demonstrates potent in vitro activity against CRKP, outperforming TGC, and represents a promising therapeutic candidate. The identification of procedure-related risk factors and prognostic biomarkers, such as SAA, provides a framework for clinical risk stratification and supports the implementation of targeted infection control measures in high-risk respiratory care settings.