Utility of surveillance blood cultures in patients undergoing hematopoietic stem cell transplantation

Background Surveillance blood cultures are often obtained in hematopoietic stem cell transplant (HSCT) patients for detection of bloodstream infection. The major aims of this retrospective cohort study were to determine the utility of the practice of obtaining surveillance blood cultures from asymptomatic patients during the first 100 post-transplant days and to determine if obtaining more than one positive blood culture helps in the diagnosis of bloodstream infection. Methods We conducted a 17-month retrospective analysis of all blood cultures obtained for patients admitted to the hospital for HSCT from January 2010 to June 2011. Each patient’s clinical course, vital signs, diagnostic testing, treatment, and response to treatment were reviewed. The association between number of positive blood cultures and the final diagnosis was analyzed. Results Blood culture results for 205 patients were reviewed. Cultures obtained when symptoms of infection were present (clinical cultures) accounted for 1,033 culture sets, whereas 2,474 culture sets were classified as surveillance cultures (no symptoms of infection were present). The total number of positive blood cultures was 185 sets (5.3% of cultures obtained) and accounted for 84 positive culture episodes. Incidence of infection in autologous, related allogeneic and unrelated allogeneic transplants was 8.3%, 20.0%, and 28.6% respectively. Coagulase-negative staphylococci were the most common organisms isolated. Based on our application of predefined criteria there were 29 infections and 55 episodes of positive blood cultures that were not infections. None of the patients who developed infection were diagnosed by surveillance blood cultures. None of the uninfected patients with positive blood cultures showed any clinical changes after receiving antibiotics. There was a significant difference between the incidence of BSI in the first and second 50-day periods post-HSCT. There was no association between the number of positive blood cultures and the final diagnosis. Conclusion Surveillance blood cultures in patients who have undergone HSCT do not identify bloodstream infections. The number of positive blood cultures was not helpful in determining which patients had infection. Patients are at higher risk of infection in the first 50 days post-transplant period

Antibiotic Prevention of Acute Exacerbations of COPD

An estimated 24 million persons in the United States have COPD on the basis of lung-function testing.1 Globally, COPD is the fourth leading cause of death,2 and in the United States it is the third most common cause of death and chronic complications.3 The average person with COPD has one to two acute exacerbations each year, with wide variation from patient to patient.4 In 2000 in the United States, 726,000 patients were hospitalized with acute exacerbations of COPD.1 During an acute exacerbation, antibiotics are generally administered for 5 to 10 days,5 creating a national burden of 120 million to 480 million antibiotic-days annually. The median hospital stay per exacerbation has been estimated at 9 days.6 In a 2007 Canadian study, the median cost of a hospital stay after an acute exacerbation of COPD was $9,557 (Canadian dollars).7 Acute exacerbations of COPD requiring hospitalization are associated with a 30-day rate of death from any cause of 4 to 30%.6 A study in Sweden showed an all-cause mortality of 26% at 30 days and of 69% at 3 years.8 Acute exacerbations also accelerate the progressive decline in lung function associated with COPD. Overall, the FEV1 falls by approximately 33 ml per year in patients with COPD.4 Each acute exacerbation increases the rate of decline by an additional 2 ml per year4 and by up to 7 ml per year in smokers.

Time to blood culture positivity as a predictor of clinical outcome of Staphylococcus aureus bloodstream infection

Few studies have assessed the time to blood culture positivity as a predictor of clinical outcome in bloodstream infections (BSIs). the purpose of this study was to evaluate the time to positivity (TTP) of blood cultures in patients with Staphylococcus aureus BSIs and to assess its impact on clinical outcome. We performed a historical cohort study with 91 adult patients with S. aureus BSIs. TTP was defined as the time between the start of incubation and the time that the automated alert signal indicating growth. in the culture bottle sounded. Patients with BSIs and TTPs of culture of 12 h (n = 47) were compared. Septic shock occurred in 13.6% of patients with TTPs of 12 h (P = 0.51). A central venous catheter source was more common with a BSI TTP of :512 h (P = 0.010). Univariate analysis revealed that a Charlson score of >= 3, the failure of at least one organ (respiratory, cardiovascular, renal, hematologic, or hepatic), infection with methicillin-resistant S. aureus, and TTPs of = 20 at BSI onset, inadequate empirical antibiotic therapy, hospital-acquired bacteremia, and endocarditis were not associated with mortality. Multivariate analysis revealed that independent predictors of hospital mortality were a Charlson score of >= 3 (odds ratio [OR], 14.4; 95% confidence interval [CI], 2.24 to 92.55), infection with methicillin-resistant S. aureus (OR, 9.3; 95% CI, 1.45 to 59.23), and TTPs of <= 12 h (OR, 6.9; 95% Cl, 1.07 to 44.66). in this historical cohort study of BSIs due to S. aureus, a TTP of :512 h was a predictor of the clinical outcome.Universidade Federal de São Paulo, Dept Infect Dis, São Paulo, BrazilVirginia Commonwealth Univ, Med Coll Virginia, Sch Med, Dept Internal Med, Richmond, VA 23298 USAVirginia Commonwealth Univ, Med Coll Virginia, Sch Med, Dept Pathol, Richmond, VA 23298 USAUniversidade Federal de São Paulo, Dept Infect Dis, São Paulo, BrazilWeb of Scienc

Time to blood culture positivity as a predictor of clinical outcome in patients with Candida albicans bloodstream infection

Background: Few studies have assessed the time to blood culture positivity as a predictor of clinical outcome in fungal bloodstream infections (BSIs). the purpose of this study was to evaluate the time to positivity (TTP) of blood cultures in patients with Candida albicans BSIs and to assess its impact on clinical outcome.Methods: A historical cohort study with 89 adults patients with C. albicans BSIs. TTP was defined as the time between the start of incubation and the time that the automated alert signal indicating growth in the culture bottle sounded.Results: Patients with BSIs and TTPs of culture of 36 h (n = 50) were compared. Septic shock occurred in 46.2% of patients with TTPs of 36 h (p = 0.56). A central venous catheter source was more common with a BSI TTP of = 20 at BSI onset, the development of at least one organ system failure (respiratory, cardiovascular, renal, hematologic, or hepatic), SOFA at BSI onset, SAPS II at BSI onset, and time to positivity were associated with death. By using logistic regression analysis, the only independent predictor of death was time to positivity (1.04; 95% CI, 1.0-1.1, p = 0.035), with the chance of the patient with C. albicans BSI dying increasing 4.0% every hour prior to culture positivity.Conclusion: A longer time to positivity was associated with a higher mortality for Candida albicans BSIs; therefore, initiating empiric treatment with antifungals may improve outcomes.Universidade Federal de São Paulo UNIFESP, Div Infect Dis, São Paulo, BrazilHosp Israelita Albert Einstein, Div Med Practice, São Paulo, BrazilVirginia Commonwealth, Univ Sch Med, Dept Internal Med, Richmond, VA USAUniversidade Federal de São Paulo UNIFESP, Div Infect Dis, São Paulo, BrazilWeb of Scienc

A program for sustained improvement in preventing ventilator associated pneumonia in an intensive care setting

Background Ventilator-associated pneumonia (VAP) is a common infection in the intensive care unit (ICU) and associated with a high mortality. Methods A quasi-experimental study was conducted in a medical-surgical ICU. Multiple interventions to optimize VAP prevention were performed from October 2008 to December 2010. All of these processes, including the Institute for Healthcare Improvement’s (IHI) ventilator bundle plus oral decontamination with chlorhexidine and continuous aspiration of subglottic secretions (CASS), were adopted for patients undergoing mechanical ventilation. Results We evaluated a total of 21,984 patient-days, and a total of 6,052 ventilator-days (ventilator utilization rate of 0.27). We found VAP rates of 1.3 and 2.0 per 1,000 ventilator days respectively in 2009 and 2010, achieving zero incidence of VAP several times during 12 months, whenever VAP bundle compliance was over 90%. Conclusion These results suggest that it is possible to reduce VAP rates to near zero and sustain these rates, but it requires a complex process involving multiple performance measures and interventions that must be permanently monitored

Impact of Appropriate Antimicrobial Therapy for Patients with Severe Sepsis and Septic Shock – A Quality Improvement Study

Background There is ample literature available on the association between both time to antibiotics and appropriateness of antibiotics and clinical outcomes from sepsis. In fact, the current state of debate surrounds the balance to be struck between prompt empirical therapy and care in the choice of appropriate antibiotics (both in terms of the susceptibility of infecting organism and minimizing resistance arising from use of broad-spectrum agents). The objective of this study is to determine sepsis bundle compliance and the appropriateness of antimicrobial therapy in patients with severe sepsis and septic shock and its impact on outcomes. Material This study was conducted in the ICU of a tertiary care, private hospital in São Paulo, Brazil. A retrospective cohort study was conducted from July 2005 to December 2012 in patients with severe sepsis and septic shock. Results A total of 1,279 patients were identified with severe sepsis and septic shock, of which 358 (32.1%) had bloodstream infection (BSI). The inpatient mortality rate was 29%. In evaluation of the sepsis bundle, over time there was a progressive increase in serum arterial lactate collection, obtaining blood cultures prior to antibiotic administration, administration of broad-spectrum antibiotics within 1 hour, and administration of appropriate antimicrobials, with statistically significant differences in the later years of the study. We also observed a significant decrease in mortality. In patients with bloodstream infection, after adjustment for other covariates the administration of appropriate antimicrobial therapy was associated with a decrease in mortality in patients with severe sepsis and septic shock (p = 0.023). Conclusions The administration of appropriate antimicrobial therapy was independently associated with a decline in mortality in patients with severe sepsis and septic shock due to bloodstream infection. As protocol adherence increased over time, the crude mortality rate decreased, which reinforces the need to implement institutional guidelines and monitor appropriate antimicrobial therapy compliance

Bloodstream infections with metallo-beta-lactamase-producing Pseudomonas aeruginosa: Epidemiology, microbiology, and clinical outcomes

Pseudomonas aeruginosa strains that produce metallo-beta-lactamases (MBLs) are becoming increasingly prevalent. We evaluated the epidemiological and microbiological characteristics of monomicrobial bloodstream infections caused by MBL-producing P. aeruginosa isolates, as well as the clinical outcomes in patients with these infections.Universidade Federal de São Paulo, Escola Paulista Med, BR-04023062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Div Infect Dis, BR-04023062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Lab Alerta, Hosp São Paulo, BR-04023062 São Paulo, SP, BrazilUNIFESP, EPM, Hosp São Paulo, São Paulo, BrazilHosp Israelita Albert Einstein, Intens Care Unit, São Paulo, BrazilVirginia Commonwealth Univ, Coll Med, Dept Internal Med, Richmond, VA USAUniversidade Federal de São Paulo, Escola Paulista Med, BR-04023062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Div Infect Dis, BR-04023062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Lab Alerta, Hosp São Paulo, BR-04023062 São Paulo, SP, BrazilUNIFESP, EPM, Hosp São Paulo, São Paulo, BrazilWeb of Scienc

Spin Dependence of Massive Lepton Pair Production in Proton-Proton Collisions

We calculate the transverse momentum distribution for the production of massive lepton-pairs in longitudinally polarized proton-proton reactions at collider energies within the context of perturbative quantum chromodynamics. For values of the transverse momentum Q_T greater than roughly half the pair mass Q, Q_T > Q/2, we show that the differential cross section is dominated by subprocesses initiated by incident gluons, provided that the polarized gluon density is not too small. Massive lepton-pair differential cross sections should be a good source of independent constraints on the polarized gluon density, free from the experimental and theoretical complications of photon isolation that beset studies of prompt photon production. We provide predictions for the spin-averaged and spin-dependent differential cross sections as a function of Q_T at energies relevant for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven, and we compare these with predictions for real prompt photon production.Comment: 34 pages, RevTeX including 17 figures in .ps file