From the Guidelines
Nebulized colistin is a recommended treatment option for Acinetobacter infections, particularly for respiratory infections such as pneumonia, with a typical dosing regimen of 1.25e15 MIU/day in 2-3 divided doses, as suggested by the most recent guidelines 1.
Key Considerations
- The treatment duration generally ranges from 7-14 days, depending on clinical response and infection severity.
- When preparing the medication, it should be diluted in 3-5 mL of sterile normal saline or sterile water.
- Patients should use a standard jet nebulizer with a mouthpiece or face mask for administration.
- Common side effects include bronchospasm, cough, and throat irritation, which can be mitigated by pre-treatment with a bronchodilator.
Mechanism of Action
- Nebulized colistin works by disrupting the bacterial cell membrane of Acinetobacter, leading to increased permeability and cell death.
- This localized delivery method allows for high drug concentrations at the infection site while minimizing systemic exposure and toxicity.
Combination Therapy
- Nebulized colistin may be used alone for mild infections or in combination with intravenous antibiotics for more severe cases, particularly in patients with multidrug-resistant Acinetobacter infections, as recommended by the guidelines 1.
Important Notes
- The guidelines suggest that colistin should be preserved for treating infections produced by A. baumannii strains showing resistance to all beta-lactams, fluoroquinolones, tigecycline (only for approved indications) 1.
- Polymyxin B may be a suitable alternative to colistin associated with less side effects, with a recommended dose of 1.5–3 mg/kg/day; a loading dose of 2–2.5 mg/kg is suggested 1.
From the Research
Treatment of Acinetobacter Infections with Nebulized Colistin
- The use of nebulized colistin for the treatment of Acinetobacter infections has been explored in various studies 2, 3, 4, 5, 6.
- Colistin is a polymyxin antibiotic that has been shown to be effective against multidrug-resistant Acinetobacter baumannii 3, 5.
- However, the use of colistin is associated with a risk of nephrotoxicity, particularly when used in combination with other antibacterial agents 2, 4.
Efficacy of Nebulized Colistin
- A study published in 2010 found that colistin-based regimens were effective in treating carbapenem-resistant Acinetobacter baumannii ventilator-associated pneumonia, with a clinical response rate of 66.7% 2.
- Another study published in 1999 found that intravenous colistin was effective in treating nosocomial infections caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, with a good outcome observed in 58% of patients 3.
- A systematic review and network meta-analysis published in 2021 found that colistin-based combination therapy was associated with a higher risk of nephrotoxicity, but was still an effective treatment option for multidrug-resistant Acinetobacter baumannii infections 4.
Safety and Tolerability
- A prospective cohort study published in 2005 found that colistin was safe and effective for the treatment of Acinetobacter and Pseudomonas infections, with no significant difference in renal function or clinical outcomes compared to other antibiotics 5.
- However, a systematic review and meta-analysis published in 2020 found that colistin heteroresistance was common in Acinetobacter spp., and that prior exposure to colistin was associated with a higher proportion of resistant subpopulations 6.
Nebulized Colistin Specifics
- While the studies mentioned above primarily focused on intravenous colistin, nebulized colistin has been used as an adjunctive therapy for the treatment of ventilator-associated pneumonia caused by multidrug-resistant Acinetobacter baumannii 2.
- The use of nebulized colistin may help to reduce the risk of nephrotoxicity associated with intravenous colistin, while still providing effective treatment against Acinetobacter infections.