High-dose Colistin Research Articles

High-dose colistin for microbiologically documented serious respiratory infections associated with carbapenem-resistant Acinetobacter baummannii in critically ill cancer patients: a retrospective cohort study

Background: Recent studies suggested that high doses of colistin are necessary in the treatment of serious infections. However, few studies have evaluated such treatment. The objective of this study was to evaluate the effectiveness and nephrotoxicity of high-dose colistin in critically ill patients with respiratory infections associated with carbapenem-resistant Acinetobacter baumannii (CRAB). Methods: This was a retrospective cohort study of critically ill cancer patients who received high-dose intravenous colistin for treatment of CRAB-related respiratory infections. Patients received colistimethate sodium 9 million IU/day or an equivalent dose, adjusted for renal function. Treatment effectiveness was evaluated by determining the microbiological clearance, recurrent and new CRAB-related infections, and mortality in the intensive care unit (ICU). Nephrotoxicity was defined according to the RIFLE (risk, injury, failure, loss, and end-stage kidney disease) criteria. Results: A total of 89 patients met the inclusion criteria. Microbiological clearance was observed in 51 (66.2%) subjects who had at least 2 follow-up cultures (n = 77). In patients who achieved microbiological clearance, recurrent and new CRAB-related infections occurred in 3 (5.9%) and 9 (17.6%) subjects, respectively. Fifty-seven patients (64%) died in the ICU. Thirty-five (39.3%) subjects developed nephrotoxicity according to the RIFLE criteria, which was classified as risk in 4 (11.4%) subjects, injury in 8 (22.8%) subjects, and failure in 21 (60%) subjects. Conclusions: In critically ill cancer patients, high-dose colistin was associated with microbiological clearance in about two-thirds of the subjects with CRAB-related respiratory infections but mortality was high. A significant portion of patients developed nephrotoxicity while receiving colistin therapy.

Successful treatment of extensively drug-resistant Pseudomonas aeruginosa osteomyelitis using a colistin- and tobramycin-impregnated PMMA spacer

Discovered in 1949, the antibiotic colistin was initially used for therapeutic purposes. Parenteral use of colistin was gradually abandoned because of its side-effect profile, especially its nephrotoxicity and neurotoxicity. Despite the risk of these potentially serious adverse effects, increasing resistance of Gram-negative bacteria has led to a renaissance of intravenous use of colistin in the last few years. Local administration of colistin is an alternative method to minimise the risk of systemic toxicity.We present a case of extensively drug-resistant Pseudomonas aeruginosa osteomyelitis treated successfully with high-dose colistin- and tobramycin-impregnated bone cement as a drug delivery vehicle. For the first time, local colistin concentrations in drainage and synovial fluid were quantified in order to determine the optimal dose and to minimise serious side effects. Insertion of a bone cement spacer loaded with a high dose of tobramycin and colistin resulted in local colistin levels at the infection site that exceeded the minimum inhibitory concentration (MIC) of colistin against the isolated P. aeruginosa five-fold on Day 4. Thus, the treatment may be expected to exert a prolonged effect. Whereas systemic administration of colistin alone was not sufficient to treat the infection, combined local and parenteral therapy led to eradication of P. aeruginosa in this patient. Plasma colistin levels remained in the therapeutic range, which confirms the systemic safety of the method.

Efficacy of High-Dose Nebulized Colistin in Ventilator-Associated Pneumonia Caused by Multidrug-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii

Lu, Qin*; Luo, Rubin†; Bodin, Liliane*; Yang, Jianxin*; Zahr, Noël*; Aubry, Alexandra‡; Golmard, Jean-Louis*; Rouby, Jean-Jacques* The Nebulized Antibiotics Study Group Author Information

Efficacy of High-dose Nebulized Colistin in Ventilator-associated Pneumonia Caused by Multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii

Colistin often remains the only active agent against multidrug-resistant Gram-negative pathogens. The aim of the study was to assess efficacy of nebulized colistin for treating ventilator-associated pneumonia (VAP) caused by multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii. One hundred and sixty-five patients with VAP caused by P. aeruginosa and A. baumannii were enrolled in a prospective, observational, and comparative study. The sensitive strain group included 122 patients with VAP caused by P. aeruginosa and A. baumannii susceptible to β-lactams, aminoglycosides, or quinolones and treated with intravenous antibiotics for 14 days. The multidrug-resistant strain group included 43 patients with VAP caused by multidrug-resistant P. aeruginosa and A. baumannii and treated with nebulized colistin (5 million international units every 8 h) either in monotherapy (n=28) or combined to a 3-day intravenous aminoglycosides for 7-19 days. The primary endpoint was clinical cure rate. Aerosol was delivered using vibrating plate nebulizer. After treatment, clinical cure rate was 66% in sensitive strain group and 67% in multidrug-resistant strain group (difference -1%, lower limit of 95% CI for difference -12.6%). Mortality was not different between groups (23 vs. 16%). Among 16 patients with persisting or recurrent P. aeruginosa infection, colistin minimum inhibitory concentration increased in two patients. Nebulization of high-dose colistin was effective to treat VAP caused by multidrug-resistant P. aeruginosa or A. baumannii. Its therapeutic effect was noninferior to intravenous β-lactams associated with aminoglycosides or quinolones for treating VAP caused by susceptible P. aeruginosa and A. baumannii.

Hypersensitivity pneumonitis due to high-dose colistin aerosol therapy

We report a case of hypersensitivity pneumonitis, possibly due to aerosolized colistin therapy for severe multi-resistant Gram-negative pneumonia. Microbiological eradication was achieved with colistin therapy, which was stopped after 12 days in view of rising eosinophilia and possible lung fibrosis. The eosinophil count started to normalize 3 days after stopping colistin therapy and the patient was eventually weaned to minimal ventilatory support.