| Objective To investigate the characteristics of drug resistance gene spectrum and immune characteristics of carbapenemresistant Acinetobacter baumannii（CRAB） in elderly patients with ventilator-associated pneumonia（VAP）, and to analyze and compare the efficacy of different treatment regimens, so as to provide reference for clinical treatment. Methods A total of 150 elderly patients with ventilatorassociated pneumonia（VAP） admitted to Langfang People's Hospital from August 2022 to January 2025 were enrolled. According to the detection results of CRAB resistance-related genes, the patients were divided into the drug-resistant group（59 cases） and the non-drug-resistant group（91 cases）, and the immune characteristics（T lymphocyte subsets, immunoglobulins） of the two groups were compared. In addition, based on different treatment regimens, the patients were divided into the eravacycline group（29 cases, treated with eravacycline combined with cefoperazone-sulbactam） and the conventional group（30 cases, treated with colistin B combined with cefoperazone-sulbactam）. The T lymphocyte subsets, immunoglobulins, inflammatory indicators [C-reactive protein（CRP）, interleukin-4（IL-4）, IL-6], clinical efficacy（effective rate at 5 days of treatment, ICU hospitalization time, 28-day mortality rate） and safety were compared between the two groups. Results The main resistance-related genes detected by CRAB resistance-related gene testing were blaOXA-51（100.00%） and blaOXA-23（79.66%）, and the detection rates of active efflux pump genes abe M, mac B, ade J and cra A were all 100.00%. At the baseline before treatment, the levels of CD4+, CD4+/CD8+, IgA, IgG and IgM in the drug-resistant group were lower than those in the non-drug-resistant group. After 5 days of treatment, the levels of CD3+, CD4+, CD4+/CD8+ and immunoglobulins in both groups were higher than those before treatment, and the above indicators in the drugresistant group were still lower than those in the non-drug-resistant group. The variation ranges of CD4+, CD4+/CD8+ and immunoglobulins before and after treatment in the drug-resistant group were smaller than those in the non-drug-resistant group（P<0.05）. In the comparison of treatment regimens, there were no significant differences in all indicators between the two groups before treatment（P>0.05）. After 5 days of treatment, the levels of CD3+, CD4+, IgA, IgG and IgM in both groups were higher than those before treatment, while the levels of CRP, IL-4 and IL-6 were lower than those before treatment. The level of CD4+/CD8+ in the eravacycline group was higher than that in the conventional group, and the levels of CRP, IL-4 and IL-6 were lower than those in the conventional group. The variation ranges of CD4+/CD8+ ratio, CRP, IL-4 and IL-6 before and after treatment in the eravacycline group were larger than those in the conventional group（P<0.05）. The total effective rate of the eravacycline group was higher than that of the conventional group, the ICU length of stay was shorter than that of the conventional group, and the 28-day mortality rate was lower than that of the conventional group（P<0.05）. There was no significant difference in the incidence of adverse reactions between the two groups（P>0.05）. Conclusion Carbapenemase-mediated blaOXA-51 and blaOXA-23 resistance are the main CRAB resistance-related genes in elderly patients with VAP. The infection of CRAB resistant strains is closely related to immune dysfunction and inflammatory response. The treatment regimen of eravacycline combined with cefoperazone sulbactam can more effectively control infection, reduce inflammation, improve immune function, shorten ICU hospitalization time, reduce mortality, and have similar safety. |
