Safety and effectiveness of colistin compared with tobramycin for multi-drug resistant Acinetobacter baumannii infections

Abstract

BackgroundNosocomial infections due to multi-drug resistant Acinetobacter baumannii are often treated with colistin, but there are few data comparing its safety and efficacy with other antimicrobials.MethodsA retrospective cohort study of patients treated with colistin or tobramycin for A. baumannii infections in intensive care units (ICUs) at Groote Schuur hospital. Colistin was used for A. baumannii isolates which were resistant to all other available antimicrobials. In the tobramycin group, 53% of the isolates were only susceptible to tobramycin and colistin. We assessed ICU mortality, nephrotoxicity and time to the first negative culture.Results32 patients, with similar admission APACHE scores and serum creatinine, were treated with each antimicrobial. There were no significant differences between the colistin and tobramycin groups in ICU mortality (p = 0.54), nephrotoxicity (p = 0.67), change in creatinine from baseline to highest subsequent value (p = 0.11) and time to microbiological clearance (p = 0.75). The hazard ratio for total in-hospital survival in patients treated with colistin compared to tobramycin was 0.43 (95% CI 0.19 to 0.99).ConclusionOur study suggests that colistin and tobramycin have similar risks of nephrotoxicity and are equally efficacious. Colistin is an acceptable antibiotic for the treatment of A. baumanii infections when the organism is resistant to other available antimicrobials.

Intravenous polymyxins: Revival with puzzle

“…It has been reported that the nephrotoxicity of colistin was not significantly different compared to tobramycin (39), immepenem (32) or ampicillin/sulbactam (42), while the colistin-based treatment had a significantly higher nephrotoxicity than tigecycline-based treatment (36,41).…”

“…This prospective study found no difference regarding clinical and micrological outcomes in both of the studies. Also, there was no significant difference in ICU mortality between the colistin and tobramycin treatment in infections due to MDR A. baumannii (39 …”

“…It's indicated that the mortality ranged from 0% to 74.3% (4,21,(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37), clinical response (cure and improvement) rate 7-82.1%, and microbiological eradication 27.3-73.9% (24,(33)(34)(35)(36)(37)(38). In respect to the colistin only susceptible strains, it's reported that the mortality in hospitals of intravenous colistin monotherapy was 50% (16/32) (Figure 2), 11 patients died in Intensive Care Unit (ICU) (39), and clinical cure was obtained in 82.1% of infectious episodes (23/28) and bacteriological clearance was achieved in 73.9% (17/23) of the cured infectious episodes (38).…”

“…So CMS dosing should be adjusted in renal impaired patients according to estimated glomerular filtration rate or creatinine clearance (31,39), and polymyxin B used to be so (43). However, recent data suggest that polymyxin B does not require adjustment for renal dysfunction (78,85,86).…”

Systematic review of the evidence for rational dosing of colistin

“…[38] A local study found that the risk of nephrotoxicity of colistin (dosed at the relatively low total daily dose of 6 MU of CMS) was similar to that of tobramycin. [39] Colistin's nephrotoxicity is dose-dependent and mostly mild and reversible. [25,38,40] One study showed that rates of nephrotoxicity were significantly higher in patients receiving daily maintenance doses greater than the equivalent of 12 MU of CMS in a 70 kg patient.…”