Investigation of electrical stimulus on chitosan film based DDS.

Controlled drug release is crucial for targeted implant smart drug delivery system (DDS). In this work a chitosan film loaded with green food coloring is fabricated to demonstrate the concepts of drug release using electrical stimulus. A simulation model is also developed to explain the physical phenomena of this drug release using finite element method (FEM). It is found that drug delivery is increased with applied electric field to the electrodes on chitosan film. The AC electrokinetic force generated from electrical excitation is a factor influencing this phenomenon. Several controlled and stimuli experiments are conducted with different electric fields and frequencies. The spectral absorbance of treated solution after the experiment is measured using a spectrophotometer to quantify the dye release. It is verified statistically with 99% level of significance that the amount of dye release has increased with applied electric field. Thus this work has shown that application of electric field can be a potential candidate for controlled DDS using chitosan film.

Institutional perspective on the impact of positive blood cultures on the economic and clinical outcomes of patients with complicated skin and skin structure infections: focus on gram-positive infections.

BACKGROUND: Traditionally, skin and skin structure infections (SSSIs) have been viewed as having a lower risk of mortality, morbidity, and cost compared with other types of infection. The influence of secondary bacteremia on the medicoeconomic outcomes of patients with SSSIs has not been well described. OBJECTIVE: The goal of this study was to evaluate the impact of bacteremia complicating SSSIs on length of hospital stay and costs. METHODS: This was a retrospective cohort study involving 579 patients with culture-positive SSSIs who were admitted to Barnes-Jewish Hospital, a major academic medical center, between April 1, 2005, and December 31, 2007. The outcomes evaluated in this analysis included hospital mortality, length of stay, hospital costs, and hospital readmission. RESULTS: Secondary bacteremia was present in 277 (47.8%) patients. Hospital mortality was statistically greater among patients with bacteremia (7.9% vs 1.0%; P < 0.001). The unadjusted median length of stay in bacteremic patients was 7.1 days compared with 2.8 days in those without bacteremia (P < 0.001 by log-rank test). This finding correlated with total hospital costs, which were greater in patients with bacteremia (median values: $14,623 vs $5841.50; P < 0.001). In a Cox model controlling for multiple confounders, bacteremia independently correlated with hospital duration (adjusted hazard ratio [HR], 1.820; 95% CI, 1.654-2.003; P < 0.001) and hospital costs (adjusted HR, 1.895; 95% CI, 1.723-2.083; P < 0.001). Hospital readmission within 30 days of discharge was also significantly more common among patients with SSSIs complicated by bacteremia (24.5% vs 12.9%; P < 0.001). CONCLUSIONS: Bacteremia complicating SSSIs occurred in almost 50% of patients infected with gram-positive bacteria in our institution. Beyond its impact on mortality, bacteremia is associated with increased length of stay, hospital costs, and readmission. However, these data are from a single academic medical center and may not be adjusted for all applicable confounders.

Hospitalizations with healthcare-associated complicated skin and skin structure infections: impact of inappropriate empiric therapy on outcomes.

OBJECTIVE: Inappropriate empiric therapy worsens outcomes in certain healthcare-associated infections (HCAI). We studied the association of inappropriate empiric therapy with outcomes in patients with HCA complicated skin and skin structure infections (cSSSI). DESIGN: A single-center retrospective cohort study. PATIENTS: Hospitalized with a culture-positive cSSSI. MEASUREMENTS: We defined HCA-cSSSI as having ≥1 of these risk factors: (1) recent hospitalization, (2) recent antibiotics, (3) hemodialysis, (4) transfer from a nursing home, and inappropriate treatment as no antimicrobial therapy active against the pathogen(s) within 24 hours of obtaining culture specimen. We performed descriptive and multivariate statistics to compute the impact of inappropriate empiric therapy on outcomes. Hospital length of stay (LOS) served as primary and mortality as secondary outcomes. RESULTS: Of the 717 patients with culture-positive cSSSI, 527 (73.5%) had HCAI, of whom 405 (76.9%) received appropriate treatment. A higher proportion of those receiving inappropriate than appropriate treatment had a decubitus ulcer (29.5% vs. 10.9%, P < 0.001), a device-associated infection (42.6% vs. 28.6%, P = 0.004), or bacteremia (68.9% vs. 57.8%, P = 0.028). The frequency of methicillin-resistant Staphylococcus aureus (MRSA) did not differ between the groups. The low overall unadjusted mortality rate did not vary based on initial treatment. In a multivariable analysis adjusting for potential confounders inappropriate therapy had an attributable increase in hospital LOS of 1.8 days (95% CI, 1.4-2.3). CONCLUSION: Similar to other populations with HCAI, HCA-cSSSI patients are likely to receive inappropriate empiric therapy for their infection. This early exposure is associated with a significant prolongation of the hospitalization by nearly 2 days.

Bacteremia increases the risk of death among patients with soft-tissue infections.

BACKGROUND: Soft-tissue infections traditionally have been viewed as carrying a lower risk of death than other types of infection such as pneumonia, blood stream, and intra-abdominal. The influence of secondary bacteremia on the outcomes of patients with soft-tissue infections is not well described. OBJECTIVES: To describe the risk factors for bacteremia among patients admitted to an urban medical center with soft-tissue infections and the influence of bacteremia on outcomes. METHODS: A retrospective cohort study of 717 patients with culture-positive non-necrotizing soft-tissue infections admitted between April 1, 2005, and December 31, 2007. RESULTS: Bacteremia was present in 52% of the patients. Increasing age, previous hospitalization, decubitus or lower-extremity ulcers, device-related soft-tissue infection, and polymicrobial infection were independent predictors of bacteremia. Intensive care unit admission (adjusted odds ratio [AOR] 3.57; 95% confidence interval [CI] 2.17, 5.86), lower-extremity ulcer (AOR 3.43; 95% CI 2.07, 5.70), and bacteremia (AOR 6.37; 95% CI 3.34, 12.12) were independent predictors of in-hospital death. When patients with device-related soft-tissue infections were excluded, the rate of secondary bacteremia was 37.6% (201/535), and it remained an independent predictor of in-hospital death. CONCLUSIONS: The occurrence of bacteremia in soft-tissue infections is associated with a greater risk of death. Health care providers should be aware of the risk factors for bacteremia in patients with soft-tissue infections in order to provide more appropriate initial antimicrobial therapy and to ascertain its presence as a prognostic indicator.

Epidemiology and outcomes of hospitalizations with complicated skin and skin-structure infections: implications of healthcare-associated infection risk factors.

OBJECTIVE: Healthcare-associated infections are likely to be caused by drug-resistant and possibly mixed organisms and to be treated with inappropriate antibiotics. Because prompt appropriate treatment is associated with better outcomes, we studied the epidemiology of healthcare-associated complicated skin and skin-structure infections (cSSSIs). PATIENTS: Persons hospitalized with cSSSI and a positive culture result. METHODS: We conducted a single-center retrospective cohort study from April 2006 through December 2007. We differentiated healthcare-associated from community-acquired cSSSIs by at least 1 of the following risk factors: (1) recent hospitalization, (2) recent antibiotics, (3) hemodialysis, and (4) transfer from a nursing home. Inappropriate treatment was defined as no antimicrobial therapy with activity against the offending pathogen(s) within 24 hours after collection of a culture specimen. Mixed infections were those caused by both a gram-positive and a gram-negative organism. RESULTS: Among 717 hospitalized patients with cSSSI, 527 (73.5%) had healthcare-associated cSSSI. Gram-negative organisms were more common (relative risk, 1.24 [95% confidence interval, 1.14-1.35) and inappropriate treatment trended toward being more common (odds ratio, 1.29 [95% confidence interval, 0.85-1.95]) in healthcare-associated cSSSI than in community-acquired cSSSI. Mixed cSSSIs occurred in 10.6% of patients with healthcare-associated cSSSI and 6.3% of those with community-acquired cSSSI (P = .082) and were more likely to be treated inappropriately than to be nonmixed infections (odds ratio, 2.42 [95% confidence interval, 1.43-4.10]). Both median length of hospital stay (6.2 vs 2.9 days; P < .001) and mortality rate (6.6% vs 1.1%; P = .003) were significantly higher for healthcare-associated cSSSI than community-acquired cSSSI. CONCLUSIONS: Healthcare-associated cSSSIs are common and are likely to be caused by gram-negative organisms. Mixed infections carry a >2-fold greater risk of inappropriate treatment. Healthcare-associated cSSSIs are associated with increased mortality and prolonged length of hospital stay, compared with community-acquired cSSSIs.