Effects of systemic antibiotic therapy on bacterial resistence in the repiratory tract of mechanically ventilated patients

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Clinical decision support systems and antibiotic use

Aim To review and appraise randomised controlled trials (RCT) and 'before and after' studies published on clinical decision support systems (CDSS) used to support the use of antibiotics. Methods A literature search. was carried out in October 2006 using MEDLINE including Medical Subject Heading (MeSH) terms (1966-2006), EMBASE (Excerpta Medica, 1980-2006) and International Pharmaceutical Abstracts (IPA, 1970-2006) using the combinations of the following terms: (Decision support systems) or (CDSS) AND (antibiotics) or (anti-infectives) or (antibacterials) or (antimicrobials). Only English language papers were selected. Editorials, letters and case reports/series were excluded. The reference sections of all retrieved articles were also searched for any further relevant articles. Results Forty articles were identified. Five RCT and six 'before and after' studies were retrieved. In the RCTs, three studies used computer-based CDSS, one paper-based CDSS and one a combination of both. Two studies were conducted in primary care and three within secondary care. The primary outcomes for each study were different and only three studies were significant in the favour of the use of CDSS. 'Before and after' studies were used where RCT were Dot feasible. One 'before and after' study was excluded because it did not include any control group. The remaining five included historical control groups and evaluated the use of computer-based CDSS within secondary care. Their primary outcomes also varied but all concluded significant, benefits of CDSS. Only three of ten studies were conducted outside the USA; one in Switzerland and two in Australia. Conclusion CDSS could be a powerful tool to improve clinical care and patient outcomes. It presents a promising future for optimising antibiotic use. However, it is difficult to generalise as most studies were conducted in the United States. Although RCT are the 'gold standard' in research, they may not be feasible to conduct. Realising that different study designs answer different questions would allow researchers to choose the most appropriate study design to evaluate CDSS in a specified setting.Peer reviewe

Predictors of trend in CD4-positive T-cell count and mortality among HIV-1-infected individuals with virological failure to all three antiretroviral-drug classes

Background Treatment strategies for patients in whom HIV replication is not suppressed after exposure to several drug classes remain unclear. We aimed to assess the inter-relations between viral load, CD4-cell count, and clinical outcome in patients who had experienced three-class virological failure. Methods We undertook collaborative joint analysis of 13 HIV cohorts from Europe, North America, and Australia, involving patients who had had three-class virological failure (viral load >1000 copies per mL for >4 months). Regression analyses were used to quantify the associations between CD4-cell-count slope, HIV-1 RNA concentration, treatment information, and demographic characteristics. Predictors of death were analysed by Cox's proportional-hazards models. Findings 2488 patients were included. 2118 (85%) had started antiretroviral therapy with single or dual therapy. During 5015 person-years of follow-up, 276 patients died (mortality rate 5.5 per 100 person-years; 3-year mortality risk 15.3% (95% Cl 13.5-17.3). Risk of death was strongly influenced by the latest CD4-cell count with a relative hazard of 15.8 (95% CI 9.28-27.0) for counts below 50 cells per muL versus above 200 cells per muL. The latest viral load did not independently predict death. For any given viral load, patients on treatment had more favourable CD4-cell-count slopes than those off treatment. For patients on treatment and with stable viral load, CD4-cell counts tended to be increasing at times when the current viral load was below 10 000 copies per mL or 1.5 log(10) copies per mL below off-treatment values. Interpretation In patients for whom viral-load suppression to below the level of detection is not possible, achievement and maintenance of a CD4-cell count above 200 per muL becomes the primary aim. Treatment regimens that maintain the viral load below 10 000 copies per mL or at least provide 1.5 log(10) copies per mL suppression below the off-treatment value do not seem to be associated with appreciable CD4-cell-count decline

Incidence of tuberculosis among HIV-infected patients receiving highly active antiretroviral therapy in Europe and North America

Background. We obtained estimates of the incidence of tuberculosis (TB) among patients receiving HAART and identified determinants of the incidence. Methods. We analyzed the incidence of TB during the first 3 years after initiation of HAART among 17,142 treatment-naive, AIDS- free persons starting HAART who were enrolled in 12 cohorts from Europe and North America. We used univariable and multivariable Poisson regression models to identify factors associated with the incidence. Results. During the first 3 years (36,906 person-years), 173 patients developed TB (incidence, 4.69 cases per 1000 person-years). In multivariable analysis, the incidence rate was lower for men who have sex with men, compared with injection drug users (relative rate, 2.46; 95% confidence interval [CI], 1.51-4.01), heterosexuals (relative rate, 2.42; 95% CI, 1.64-3.59), those with other suspected modes of transmission (relative rate, 1.66; 95% CI, 0.91-3.06), and those with a higher CD4(+) count at the time of HAART initiation (relative rate per log(2) cells/mL, 0.87; 95% CI, 0.84-0.91). During 28,846 person-years of follow-up after the first 6 months of HAART, 88 patients developed TB (incidence, 3.1 cases per 1000 person-years of follow-up). In multivariable analyses, a low baseline CD4(+) count (relative rate per log(2) cells/mL, 0.89; 95% CI, 0.83-0.96), 6-month CD4(+) count (relative rate per log(2) cells/mL, 0.90; 95% CI, 0.81-0.99), and a 6-month HIV RNA level 1400 copies/mL (relative rate, 2.21; 95% CI, 1.33-3.67) were significantly associated with the risk of acquiring TB after 6 months of HAART. Conclusion. The level of immunodeficiency at which HAART is initiated and the response to HAART are important determinants of the risk of TB. However, this risk remains appreciable even among those with a good response to HAART, suggesting that other interventions may be needed to control the TB epidemic in the HIV-infected population

A highly virulent variant of HIV-1 circulating in the Netherlands.

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log <sub>10</sub> increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence