A retrospective analysis of biofilm antibiotic susceptibility testing: a better predictor of clinical response in cystic fibrosis exacerbations.

BACKGROUND: Bacteria grow as biofilms within CF airways. However, antibiotic susceptibility testing is routinely performed on planktonically-growing bacteria. This study assessed whether CF patients infected with multiresistant organisms had improved clinical outcomes if given antibiotics that inhibited their biofilm-grown bacteria. METHODS: 110 patients with pulmonary exacerbations were treated with intravenous antibiotics based on susceptibility testing of planktonically-growing bacteria. A retrospective analysis was done using bacterial isolates grown from their sputum at exacerbation. Each isolate was grown as a biofilm and combination antibiotic susceptibility testing was performed. Clinical outcomes in patients treated with biofilm-susceptible antibiotics were compared to those that were not. RESULTS: 66 of 110 patients (60%) were treated with antibiotic combinations that inhibited all of their planktonically-grown bacterial isolates, however, when the same isolates were grown as biofilms, only 24 patients (22%) had all of their biofilm-grown isolates remaining susceptible to the antibiotics (P=<0.001 ). When patients with at least one biofilm-grown susceptible isolate (n=61) were compared to those with none (n=49), there was a significant decrease in sputum bacterial density (P=0.02) and length of stay (P=0.04) and a non-significant decrease in treatment failure. Survival analyses of time to next exacerbation showed non-significant trends favoring patients treated with biofilm-effective antibiotics. CONCLUSIONS: Most patients with CF exacerbations do not receive antibiotics that inhibit all biofilm-grown bacteria from their sputum at exacerbation. Patients treated with biofilm-effective therapy seemed to have improved clinical outcomes.

Variables associated with medication errors in pediatric emergency medicine.

OBJECTIVE: Medication errors are a common cause of iatrogenic morbidity and mortality. The incidence of medication errors in pediatric emergency departments (EDs) has not been described. The objective of this study was to describe the incidence and type of drug errors in a pediatric ED and determine factors associated with risk of errors. METHODS: A retrospective cohort study was conducted of the charts of 1532 children who were treated in the ED of a pediatric tertiary care hospital during 12 randomly selected days from the summer of 2000. Two pediatricians, blinded to other study variables, independently decided whether a medication error occurred and ranked it according to a severity score. Disagreement was resolved by consensus. RESULTS: Prescribing errors were identified in 10.1% of the charts. The following variables were associated in univariate analysis with an increased proportion of errors: patients seen between 4 AM and 8 AM (odds ratio [OR]: 2.45; 95% confidence interval [CI]: 1.10-5.50), patients with severe disease (OR: 2.53; 95% CI: 1.18-5.41), medication ordered by a trainee (OR: 1.48; 95% CI: 1.03-2.11), and patients seen during weekends (OR: 1.48; 95% CI: 1.04-2.11). Among trainees, there was a higher rate of errors at the beginning of the academic year (OR: 1.67; 95% CI: 1.06-2.64). Logistic regression revealed increased risk for errors when a medication was ordered by a trainee (OR: 1.64; 95% CI: 1.06-2.52) and in seriously ill patients (OR: 1.55; 95% CI: 1.06-2.26). CONCLUSIONS: In the pediatric ED, trainees are more likely to commit prescribing errors, and the most seriously ill patients are more likely to be subjected to prescribing errors.