Factors influencing the efficacy of nebulized colistimethate sodium in the treatment of severe lung infection caused by carbapenem-resistant gram-negative bacteria.

BACKGROUND

Nebulized colistimethate sodium (CMS) can help treat carbapenem-resistant gram-negative bacteria (CR-GNB) infection. However, it remains unclear how various patient-related factors affect its efficacy.

METHODS

This was a secondary analysis of a multicenter retrospective study involving 24 hospitals in China. Patients diagnosed with severe pneumonia caused by CR-GNB and who received nebulized CMS 75 mg every 12 h for at least 3 days were included. Logistic regression was performed to examine associations with clinical outcomes.

RESULTS

A total of 314 patients were included, with an average age of 68.9 years, and 77.4% were male. Most patients (89.2%) had no history of CR-GNB infection. Pathogens exhibited resistance to imipenem (90.4%), meropenem (90.1%), and ampicillin/sulbactam (82.5%). Following treatment, the cohort achieved 76.1% microbiological efficacy and 79.3% overall clinical response rate. The mortality rate was 20.1%. Multivariable analysis revealed that age (adjusted odds ratio [aOR], 0.96; 95% confidence interval [CI], 0.92-0.997, P = 0.04), history of stroke (aOR, 0.16; 95% CI, 0.04-0.77, P = 0.02), and combination treatment with tigecycline (aOR, 0.11; 95% CI, 0.22-0.50; P = 0.004) were independently associated with lower bacterial clearance. Use of moxifloxacin before CMS administration (aOR, 0.11; 95% CI, 0.02-0.55; P = 0.007) and tigecycline treatment (aOR, 0.19; 95% CI, 0.06-0.58; P = 0.003) were associated with a lower clinical response. After controlling for other variables, tigecycline treatment was associated with a higher risk of death (aOR, 4.44; 95% CI, 1.94-10.2; P < 0.0001).

CONCLUSIONS

We confirmed the clinical benefits of a nebulized CMS-based regimen for treating severe pneumonia. Several influential factors were identified, which may help optimize the clinical use of nebulized CMS.