Pediatric-specific antimicrobial susceptibility data and empiric antibiotic selection.

OBJECTIVE: Duke University Health System (DUHS) generates annual antibiograms combining adult and pediatric data. We hypothesized significant susceptibility differences exist for pediatric isolates and that distributing these results would alter antibiotic choices. METHODS: Susceptibility rates for Escherichia coli isolates from patients aged ≤12 years between July 2009 and September 2010 were compared with the 2009 DUHS antibiogram. Pediatric attending and resident physicians answered case-based vignettes about children aged 3 months and 12 years with urinary tract infections. Each vignette contained 3 identical scenarios with no antibiogram, the 2009 DUHS antibiogram, and a pediatric-specific antibiogram provided. Effective antibiotics exhibited >80% in vitro susceptibility. Frequency of antibiotic selection was analyzed by using descriptive statistics. RESULTS: Three hundred seventy-five pediatric isolates were identified. Pediatric isolates were more resistant to ampicillin and trimethoprim-sulfamethoxazole (TMP-SMX) and less resistant to amoxicillin-clavulanate and ciprofloxacin (P < .0005 for all). Seventy-five resident and attending physicians completed surveys. In infant vignettes, physicians selected amoxicillin-clavulanate (P < .05) and nitrofurantoin (P < .01) more often and TMP-SMX (P < .01) less often with pediatric-specific data. Effective antibiotic choices increased from 68.6% to 82.2% (P = .06) to 92.5% (P < .01) across scenarios. In adolescent vignettes, providers reduced TMP-SMX use from 66.2% to 42.6% to 19.0% (P < .01 for both). Effective antibiotic choices increased from 32.4% to 57.4% to 79.4% (P < .01 and P = .01). CONCLUSIONS: Pediatric E. coli isolates differ significantly in antimicrobial susceptibility at our institution, particularly to frequently administered oral antibiotics. Knowledge of pediatric-specific data altered empirical antibiotic choices in case vignettes. Care of pediatric patients could be improved with use of a pediatric-specific antibiogram

Variability in performance measures for assessment of hypertension control.

BACKGROUND: Definitions of multiple performance measures exist for the assessment of blood pressure control; however, limited data on how these technical variations may affect actual measured performance are available. METHODS: We evaluated patients with hypertension followed routinely by cardiologists at Duke University Health System from 2009 to 2010. Provider hypertension control was compared based on reading at the last clinic visit vs the average blood pressure across all visits. The impact of home blood pressure measurements and patient exclusions endorsed by the American Heart Association, the American College of Cardiology, and the Physician Consortium for Performance Improvement were evaluated using medical record reviews. RESULTS: Among 5,552 hypertensive patients, the rate of blood pressure control based on last clinic visit was 69.1%; however, significant clinic-to-clinic variability was seen in serial clinic blood pressure measurements in individual patients (average 18 mm Hg). As a result, provider performance ratings varied considerably depending on whether a single reading or average blood pressure reading was used. The inclusion of home blood pressure measurements resulted in modestly higher rates of blood pressure control performance (+6% overall). Similarly, excluding patients who met guideline-recommended exclusion criteria increased blood pressure control rates only slightly (+3% overall). In contrast, excluding patients who were on 2 or more antihypertensive medications would have raised blood pressure control rates to 96% overall. CONCLUSION: Depending on definitions used, overall and provider-specific blood pressure control rates can vary considerably. Technical aspects of blood pressure performance measures may affect perceived quality gaps and comparative provider ratings

Angiotensin II stimulates H-ATPase activity in intercalated cells from isolated mouse connecting tubules and cortical collecting ducts

Intercalated cells in the collecting duct system express V-type H(+)-ATPases which participate in acid extrusion, bicarbonate secretion, and chloride absorption depending on the specific subtype. The activity of H(+)-ATPases is regulated by acid-base status and several hormones, including angiotensin II and aldosterone. Angiotensin II stimulates chloride absorption mediated by pendrin in type B intercalated cells and this process is energized by the activity of H(+)-ATPases. Moreover, angiotensin II stimulates bicarbonate secretion by the connecting tubule (CNT) and early cortical collecting duct (CCD). In the present study we examined the effect of angiotensin II (10 nM) on H(+)-ATPase activity and localization in isolated mouse connecting tubules and cortical collecting ducts. Angiotensin II stimulated Na(+)-independent intracellular pH recovery about 2-3 fold, and this was abolished by the specific H(+)-ATPase inhibitor concanamycin. The effect of angiotensin II was mediated through type 1 angiotensin II receptors (AT(1)-receptors) because it could be blocked by saralasin. Stimulation of H(+)-ATPase activity required an intact microtubular network - it was completely inhibited by colchicine. Immunocytochemistry of isolated CNT/CCDs incubated in vitro with angiotensin II suggests enhanced membrane associated staining of H(+)-ATPases in pendrin expressing intercalated cells. In summary, angiotensin II stimulates H(+)-ATPases in CNT/CCD intercalated cells, and may contribute to the regulation of chloride absorption and bicarbonate secretion in this nephron segment