[Clinical study on intravenous combined with aerosol inhalation of polymyxin B for the treatment of pneumonia caused by multidrug-resistant Gram-negative bacteria].

Objective: To investigate the efficacy of intravenous combined with aerosol inhalation of polymyxin B for the treatment of pneumonia caused by multidrug-resistant Gram-negative (G) bacteria.

Methods: A observational study was conducted. The clinical data of 45 patients with pneumonia due to multidrug-resistant G bacteria admitted to intensive care unit of Fujian Medical University Union Hospital from January to October in 2020 were analyzed. According to the different use methods of polymyxin B, 25 patients who received single intravenous drip (the first dose was 2.0 mg/kg, then 1.25 mg/kg, once every 12 hours) from January to April in 2020 were enrolled in the routine group, and 20 patients who received intravenous drip combined with aerosol inhalation (25 mg once every 12 hours, sputum in the airway was sucked and then sprayed aerosol) from May to October in 2020 were enrolled in the combination group. After the treatment course of polymyxin B, the total bacterial clearance rate, total clinical efficiency rate, recovery time of body temperature, time of bacterial clearance and the change of serum procalcitonin (PCT) level before and after treatment were compared between the two groups. Moreover, the incidence of adverse reactions during treatment in the two groups was observed.

Results: The results of sputum culture in the routine group were Acinetobacter baumannii in 13 patients, Klebsiella pneumoniae in 5 patients, Pseudomonas aeruginosa in 6 patients, Enterobacter cloacae in 1 patient; the sputum culture results of the combination group showed that there were 5 patients of Acinetobacter baumannii, 9 Klebsiella pneumoniae and 6 Pseudomonas aeruginosa. There was no significant difference in the results of sputum culture between the two groups (P > 0.05). The total bacterial clearance rate and the total clinical efficiency rate of the combination group were significantly higher than those in the routine group (total bacterial clearance rate: 70.0% vs. 40.0%, total clinical efficiency rate: 75.0% vs. 40.0%, both P < 0.05). The recovery time of body temperature and the time of bacterial clearance of the combination group were significantly shorter than those in the routine group [recovery time of body temperature (days): 6.0±3.9 vs. 10.2±7.3, time of bacterial clearance (days): 6.1±5.2 vs. 11.5±6.8, both P < 0.05]. No significant difference was found in serum PCT level before treatment between the two group. There was no significant difference in serum PCT level before and after treatment in the routine group [μg/L: 0.85 (0.44, 2.87) vs. 1.43 (0.76, 5.30), P > 0.05]. The serum PCT level after treatment in the combination group was significantly lower than that before treatment [μg/L: 0.27 (0.10, 0.70) vs. 0.91 (0.32, 3.53), P < 0.05], and it was significantly lower than that in the routine group [μg/L: 0.27 (0.10, 0.70) vs. 0.85 (0.44, 2.87), P < 0.01]. The incidence of renal toxicity of polymyxin B between the combination group and the routine group was not significantly different (5.0% vs. 4.0%, P > 0.05).

Conclusions: The efficacy of intravenous combined with aerosol inhalation of polymyxin B for the treatment of pneumonia due to multidrug-resistant G bacteria is better than that of intravenous drip of polymyxin B only. The aerosolized polymyxin B will not increase the risk of renal injury.