New Predictive Equation for the Estimation of Plasma Concentrations of Formed Colistin in Patients Treated with Colistimethate Sodium for Multidrug-Resistant Gram-Negative Bacterial Infections.

BACKGROUND: The clinical use of colistin methanesulphonate (CMS) is limited by potential nephrotoxicity. The selection of an efficient and safe CMS dose for individual patients is complicated by the narrow therapeutic window and high interpatient pharmacokinetic variability. In this study, a simple predictive equation for estimating the plasma concentration of formed colistin in patients with multidrug and extremely drug-resistant gram-negative bacterial infections was developed. METHODS: The equation was derived from the largest clinical cohort of patients undergoing therapeutic drug monitoring (TDM) of colistin for over 8 years in a tertiary Spanish hospital. All variables associated with Css,avg were selected in a multiple linear regression model that was validated in a second cohort of 40 patients. Measured Css,avg values were compared with those predicted by our model and a previous published algorithm for critically ill patients. RESULTS: In total, 276 patients were enrolled [the mean age was 67.2 (13.7) years, 203 (73.6%)] were male, and the mean (SD) Css,avg was 1.12 (0.98) mg/L. Age, gender, estimated glomerular filtration rate, CMS dose and frequency, and concomitant drugs were included in the model. In the external validation, the previous algorithm appeared to yield more optimized colistin plasma concentrations when all types of Css,avg values (high and low) were considered, while our equation yielded a more optimized prediction in the subgroup of patients with low colistin plasma concentrations (Css,avg <1.5 mg/L). CONCLUSIONS: The proposed equation may help clinicians to better use CMS among a wide variety of patients, to maximize efficacy and prevent nephrotoxicity. A further prospective PK study is warranted to externally validate this algorithm.

Cross-Sectional Survey on the Current Role of Clinical Pharmacists among Antimicrobial Stewardship Programmes in Catalonia: Much Ado about Nothing.

BACKGROUND: Antimicrobial resistance killed 1.27 million people in 2019, so urgent actions are desperately needed. Antimicrobial stewardship programmes (ASPs) are essential to optimize antimicrobial use. The objective was to acknowledge the current role of clinical pharmacists engaged in ASP activities in Catalonia. METHODS: This was a cross-sectional survey shared through the Catalan Infection Control Programme (VINCat). The survey consisted of four sections and was sent by e-mail. RESULTS: A total of 69.0% of the centres answered. Pharmacists dedicated a median of 5.0 h per week (2.1 h/week/100 acute care beds), representing 0.15 full time equivalents. The ASP lacked information technology (IT) support, as only 16.3% of centres automatically calculated defined daily doses and days of therapy. Those with less than 15% of their time available for ASPs conducted fewer clinical activities, especially prospective audits and feedback. Those without official infectious diseases training also performed fewer clinical activities, but training was less determinant than IT support or time. Pharmacists performed interventions mostly through annotation in the medical records. CONCLUSIONS: Clinical pharmacists from Catalonia dedicated to ASPs present an important lack of time and IT support to perform clinical activities. Pharmacists should also improve their clinical skills and try to conduct clinical advice to prescribers, either by phone or face-to-face.