Safety and Efficacy of Nebulized Inhalation of Polymyxin B Sulfate for Carbapenem-Resistant Gram-Negative Bacterial Pneumonia: A Multi-Center, Prospective, Observational Study.

BACKGROUND

Carbapenem-resistant gram-negative bacterial (CRGNB) pneumonia is a severe clinical challenge. This study aimed to assess the efficacy and safety of nebulized polymyxin B sulfate for its treatment.

METHODS

A multicenter, prospective, observational study was conducted in seven hospitals in Zhejiang Province, China, from January to October 2022. Patients diagnosed with CRGNB pneumonia and treated with nebulized polymyxin B sulfate were included. Data on baseline characteristics, microbiology, adverse events, and clinical outcomes were collected. The primary endpoint was the pathogen eradication rate 14 days after discontinuation of inhalation therapy. Secondary endpoints included microbial alternation, incidence of bronchospasm, and 28-day and 60-day mortality rates.

RESULTS

A total of 91 patients with CRGNB pneumonia received nebulized polymyxin B sulfate. The duration of inhalation ranged from 7 to 15 days, with a median of 9 days. Concurrent intravenous polymyxin B was administered in 72.5% of patients. Among 87 patients with available microbiological data, pathogen eradication was achieved in 33 cases (37.9%) and presumed eradication in 30 cases (34.5%), resulting in a total eradication rate of 72.4%. Persistent CRGNB infection was observed in 24 patients (27.6%). Microbial alternation occurred in 26 patients (29.9%), mainly involving intrinsically polymyxin B-resistant species such as Burkholderia and Serratia spp., and 4 polymyxin B-resistant CRGNB strains (1 case of Acinetobacter baumannii, 2 cases of Klebsiella pneumoniae, and 1 case of Pseudomonas aeruginosa). The incidence of bronchospasm was 3.3% (3/91), all of which were relieved with inhaled corticosteroids and short-acting β2 agonists without discontinuation of inhalation therapy. The 28-day and 60-day mortality rates were 18.7% and 28.6%, respectively.

CONCLUSION

Nebulized polymyxin B sulfate achieved a high pathogen eradication rate, low microbial alternation, and good airway tolerability in patients with CRGNB pneumonia; supporting its efficacy and safety as a therapeutic option.