Intravenous Polymyxin B as Adjunctive Therapy to High-Dose Tigecycline for the Treatment of Nosocomial Pneumonia Due to Carbapenem-Resistant Acinetobacter baumannii and Klebsiella pneumoniae: A Propensity Score-Matched Cohort Study
Lei Zha, Xue Zhang, Yusheng Cheng, Qiancheng Xu, Lingxi Liu, Simin Chen, Zhiwei Lu, Jun Guo, Boris Tefsen
Abstract
Although the combination of polymyxin and tigecycline is widely used in treating carbapenem-resistant bacterial infections, the benefit of this combination is still uncertain. To assess whether adding polymyxin B to the high-dose tigecycline regimen would result in better clinical outcomes than the high-dose tigecycline therapy in patients with pneumonia caused by carbapenem-resistant Klebsiella pneumoniae and Acinetobacter baumannii, we conducted a propensity score-matched cohort study in a single center between July 2019 and December 2021. Of the 162 eligible patients, 102 were included in the 1:1 matched cohort. The overall 14-day mortality in the matched cohort was 24.5%. Compared with high-dose tigecycline, the combination therapy was not associated with better clinical outcomes, and showed similar 14-day mortality (OR, 0.72, 95% CI 0.27–1.83, p = 0.486), clinical cure (OR, 1.09, 95% CI 0.48–2.54, p = 0.823), microbiological cure (OR, 0.96, 95% CI 0.39–2.53, p = 0.928) and rate of nephrotoxicity (OR 0.85, 95% CI 0.36–1.99, p = 0.712). Subgroup analyses also did not demonstrate any statistical differences. Based on these results, it is reasonable to recommend against adding polymyxin B to the high-dose tigecycline regimen in treating pneumonia caused by carbapenem-resistant K. pneumoniae and A. baumannii.