Enhanced antimicrobial stewardship based on rapid phenotypic antimicrobial susceptibility testing for bacteraemia in patients with haematological malignancies: a randomized controlled trial.

OBJECTIVES: Recently, rapid phenotypic antimicrobial susceptibility testing (AST) based on microscopic imaging analysis has been developed. The aim of this study was to determine whether implementation of antimicrobial stewardship programmes (ASP) based on rapid phenotypic AST can increase the proportion of patients with haematological malignancies who receive optimal targeted antibiotics during early periods of bacteraemia. METHODS: This randomized controlled trial enrolled patients with haematological malignancies and at least one positive blood culture. Patients were randomly assigned 1:1 to conventional (n = 60) or rapid phenotypic (n = 56) AST. The primary outcome was the proportion of patients receiving optimal targeted antibiotics 72 hr after blood collection for culture. RESULTS: The percentage receiving optimal targeted antibiotics at 72 hr was significantly higher in the rapid phenotypic AST group (45/56, 80.4%) than in conventional AST group (34/60, 56.7%) (relative risk (RR) 1.42, 95% confidence interval (CI) 1.09-1.83). The percentage receiving unnecessary broad-spectrum antibiotics at 72 hr was significantly lower (7/26, 12.5% vs 18/60, 30.0%; RR 0.42, 95% CI 0.19-0.92) and the mean time to optimal targeted antibiotic treatment was significantly shorter (38.1, standard deviation (SD) 38.2 vs 72.8, SD 93.0 hr; p < 0.001) in the rapid phenotypic AST group. The mean time from blood collection to the AST result was significantly shorter in the rapid phenotypic AST group (48.3, SD 17.6 vs 83.1, SD 22.2 hr). DISCUSSION: ASP based on rapid phenotypic AST can rapidly optimize antibiotic treatment for bacteraemia in patients with haematological malignancy. Rapid phenotypic AST can improve antimicrobial stewardship in immunocompromised patients.

Chlorhexidine sensitivity in staphylococci isolated from patients with central line-associated bloodstream infection.

Since 2011, 2% chlorhexidine in 70% isopropyl alcohol (2% chlorhexidine tincture) has been widely used in Korea. To investigate changes in chlorhexidine sensitivity of staphylococci causing central line-associated bloodstream infections, 264 blood culture isolates from adult patients treated in intensive care units of five university hospitals between 2008 and 2016 were analysed. We observed no significant changes in chlorhexidine minimum inhibitory and bactericidal concentrations, or in the prevalence of resistance-associated genes before and after introduction of 2% chlorhexidine tincture. Thus, there was no evidence of increased resistance to chlorhexidine in staphylococci causing central line-associated bloodstream infections.