Alkane/Water Partition Coefficient Calculation Based on the Modified AM1 Method and Internal Hydrogen Bonding Sampling Using COSMO-RS.

We introduce a physics-based model for calculating partition coefficients of solutes between water and alkanes, using a combination of a semi-empirical method for COSMO charge density calculation and statistical sampling of internal hydrogen bonds (IHBs). We validate the model on the experimental partition data (∼3500 molecules) of small organics, drug-like molecules, and statistical assessment of modeling of proteins and ligand drugs. The model combines two novel algorithms: a bond-correction method for improving the calculation of COSMO charge density from AM1 calculations and a sampling method to deal with IHBs. From a comparison of simulated and experimental partition coefficients, we find a root-mean-square deviation of roughly one log 10 unit. From IHB analysis, we know that IHBs can be present in two states: open (in water) and closed (in apolar solvent). The difference can lead to a shift of as much as two log 10 units per IHB; not taking this effect into account can lead to substantial errors. The method takes a few minutes of calculation time on a single core, per molecule. Although this is still much slower than quantitative structure-activity relationship, it is much faster than molecular simulations and can be readily incorporated into any screening method.

The use of 3.15% chlorhexidine gluconate/70% alcohol hub disinfection to prevent central line-associated bloodstream infections in dialysis patients.

PURPOSE: Preventing CLABSI events in the dialysis inpatient population represents significant challenges. Bacteremia associated with lines or grafts are common health-associated infections that lead to adverse patient outcomes. Dialysis patients represent a much higher infection risk due to health frequency needs, more frequent hospitalizations, multiple comorbidity issues, fistula functionality, and multiple attempts for line access leading to additional complications, costs, morbidity, and mortality. METHODS: An observational study was conducted including central line device days, CLABSI events, and possible confounding variables in admitted dialysis patients. All CLABSI data were identified according to the Centers for Disease Control and Prevention's National Healthcare Safety Network's definitions for CLABSIs. The intervention involved the removal of 70% alcohol swabs and alcohol hub disinfecting caps, then replacing with swabs containing 3.15% chlorhexidine gluconate/70% alcohol for central line hub disinfection and vascular graft access skin disinfection. RESULTS: The 5-year preintervention period (2008-2012) involved 7568 central line days, 11 CLABSI events, and a 1.45 per 1000 device day rate. The 6-month trial period involved 1559 central line days and no CLABSI events. The 5-year postimplementation period (2013-2017) involved 9787 central line days, 5 CLABSI events, and a 0.51 per 1000 device day rate. The postimplementation period represented a statistically significant (P value=0.0493) reduction with 65% fewer CLABSI events compared with the preimplementation period. LIMITATIONS: A limitation was variations in scrub time and dry time during central venous catheter hub access. While we were comparing 2 products, behavioral practices using these 2 products were possible influencers and represent a possible confounding variable. CONCLUSIONS: This study found that using alcohol with chlorhexidine gluconate prior to accessing central line hubs and vascular grafts allows for reduction in CLABSI events and sustains statistically significant lower CLABSI rates in the inpatient dialysis population. HIGHLIGHTS Using alcohol with chlorhexidine gluconate (CHG) before accessing central line hubs helps reduce central line-associated bloodstream infection (CLABSI) events Using alcohol with CHG before accessing vascular grafts helps reduce CLABSI events A statistically significant reduction (65%) in CLABSI events occurred after use. Statistically significant lower CLABSI rates are sustainable with use of alcohol with CHG.

Effectiveness of targeted enhanced terminal room disinfection on hospital-wide acquisition and infection with multidrug-resistant organisms and Clostridium difficile: a secondary analysis of a multicentre cluster randomised controlled trial with crossover design (BETR Disinfection).

BACKGROUND: The hospital environment is a source of pathogen transmission. The effect of enhanced disinfection strategies on the hospital-wide incidence of infection has not been investigated in a multicentre, randomised controlled trial. We aimed to assess the effectiveness of four disinfection strategies on hospital-wide incidence of multidrug-resistant organisms and Clostridium difficile in the Benefits of Enhanced Terminal Room (BETR) Disinfection study. METHODS: We did a prespecified secondary analysis of the results from the BETR Disinfection study, a pragmatic, multicentre, crossover cluster-randomised trial that assessed four different strategies for terminal room disinfection in nine hospitals in the southeastern USA. Rooms from which a patient with a specific infection or colonisation (due to the target organisms C difficile, meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci (VRE), or multidrug-resistant Acinetobacter spp) was discharged were terminally disinfected with one of four strategies: standard disinfection (quaternary ammonium disinfectant, except for C difficile, for which 10% hypochlorite [bleach] was used; reference); standard disinfection and disinfecting ultraviolet light (UV-C), except for C difficile, for which bleach and UV-C was used (UV strategy); 10% hypochlorite (bleach strategy); and bleach and UV-C (bleach and UV strategy). We randomly assigned the sequence of strategies for each hospital (1:1:1:1), and each strategy was used for 7 months, including a 1-month wash-in period and 6 months of data collection. The prespecified secondary outcomes were hospital-wide, hospital-acquired incidence of all target organisms (calculated as number of patients with hospital-acquired infection with a target organism per 10 000 patient days), and hospital-wide, hospital-acquired incidence of each target organism separately. BETR Disinfection is registered with ClinicalTrials.gov, number NCT01579370. FINDINGS: Between April, 2012, and July, 2014, there were 271 740 unique patients with 375 918 admissions. 314 610 admissions met all inclusion criteria (n=73 071 in the reference study period, n=81 621 in the UV study period, n=78 760 in the bleach study period, and n=81 158 in the bleach and UV study period). 2681 incidenct cases of hospital-acquired infection or colonisation occurred during the study. There was no significant difference in the hospital-wide risk of target organism acquisition between standard disinfection and the three enhanced terminal disinfection strategies for all target multidrug-resistant organisms (UV study period relative risk [RR] 0·89, 95% CI 0·79-1·00; p=0·052; bleach study period 0·92, 0·79-1·08; p=0·32; bleach and UV study period 0·99, 0·89-1·11; p=0·89). The decrease in risk in the UV study period was driven by decreases in risk of acquisition of C difficile (RR 0·89, 95% CI 0·80-0·99; p=0·031) and VRE (0·56, 0·31-0·996; p=0·048). INTERPRETATION: Enhanced terminal room disinfection with UV in a targeted subset of high-risk rooms led to a decrease in hospital-wide incidence of C difficile and VRE. Enhanced disinfection overcomes limitations of standard disinfection strategies and is a potential strategy to reduce the risk of acquisition of multidrug-resistant organisms and C difficile. FUNDING: US Centers for Disease Control and Prevention.

Calculation of Diffusion Coefficients through Coarse-Grained Simulations Using the Automated-Fragmentation-Parametrization Method and the Recovery of Wilke-Chang Statistical Correlation.

We introduce a model for the calculation of diffusion coefficients using dissipative particle dynamics coarse-grained molecular simulations. We validate the model on experimental diffusion data of small organics and drug-like molecules in water. The new model relies on our automated-fragmentation-parametrization protocol for cutting molecules into fragments, which are calibrated using the COSMO-RS thermodynamic model ( J. Chem. Inf. MODEL: 2016 , 56 ( 12 ), 2361 - 2377 , DOI: 10.1021/acs.jcim.6b00003 ). By simulations over the entire CULGI database of more than 11000 molecules, we recover the decades-old empirical Wilke-Chang correlation between diffusion coefficient and molar volume. We believe this is the first demonstration of the correlation by simulation or theory. From a comparison of simulated and experimental diffusion coefficients, we find that one full time unit of coarse-grained simulation equals 64 ± 13 ps real time.

Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster-randomised, multicentre, crossover study.

BACKGROUND: Patients admitted to hospital can acquire multidrug-resistant organisms and Clostridium difficile from inadequately disinfected environmental surfaces. We determined the effect of three enhanced strategies for terminal room disinfection (disinfection of a room between occupying patients) on acquisition and infection due to meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, C difficile, and multidrug-resistant Acinetobacter. METHODS: We did a pragmatic, cluster-randomised, crossover trial at nine hospitals in the southeastern USA. Rooms from which a patient with infection or colonisation with a target organism was discharged were terminally disinfected with one of four strategies: reference (quaternary ammonium disinfectant except for C difficile, for which bleach was used); UV (quaternary ammonium disinfectant and disinfecting ultraviolet [UV-C] light except for C difficile, for which bleach and UV-C were used); bleach; and bleach and UV-C. The next patient admitted to the targeted room was considered exposed. Every strategy was used at each hospital in four consecutive 7-month periods. We randomly assigned the sequence of strategies for each hospital (1:1:1:1). The primary outcomes were the incidence of infection or colonisation with all target organisms among exposed patients and the incidence of C difficile infection among exposed patients in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT01579370. FINDINGS: 31 226 patients were exposed; 21 395 (69%) met all inclusion criteria, including 4916 in the reference group, 5178 in the UV group, 5438 in the bleach group, and 5863 in the bleach and UV group. 115 patients had the primary outcome during 22 426 exposure days in the reference group (51·3 per 10 000 exposure days). The incidence of target organisms among exposed patients was significantly lower after adding UV to standard cleaning strategies (n=76; 33·9 cases per 10 000 exposure days; relative risk [RR] 0·70, 95% CI 0·50-0·98; p=0·036). The primary outcome was not statistically lower with bleach (n=101; 41·6 cases per 10 000 exposure days; RR 0·85, 95% CI 0·69-1·04; p=0·116), or bleach and UV (n=131; 45·6 cases per 10 000 exposure days; RR 0·91, 95% CI 0·76-1·09; p=0·303) among exposed patients. Similarly, the incidence of C difficile infection among exposed patients was not changed after adding UV to cleaning with bleach (n=38 vs 36; 30·4 cases vs 31·6 cases per 10 000 exposure days; RR 1·0, 95% CI 0·57-1·75; p=0·997). INTERPRETATION: A contaminated health-care environment is an important source for acquisition of pathogens; enhanced terminal room disinfection decreases this risk. FUNDING: US Centers for Disease Control and Prevention.

Coarse-Grained Models for Automated Fragmentation and Parametrization of Molecular Databases.

We calibrate coarse-grained interaction potentials suitable for screening large data sets in top-down fashion. Three new algorithms are introduced: (i) automated decomposition of molecules into coarse-grained units (fragmentation); (ii) Coarse-Grained Reference Interaction Site Model-Hypernetted Chain (CG RISM-HNC) as an intermediate proxy for dissipative particle dynamics (DPD); and (iii) a simple top-down coarse-grained interaction potential/model based on activity coefficient theories from engineering (using COSMO-RS). We find that the fragment distribution follows Zipf and Heaps scaling laws. The accuracy in Gibbs energy of mixing calculations is a few tenths of a kilocalorie per mole. As a final proof of principle, we use full coarse-grained sampling through DPD thermodynamics integration to calculate log POW for 4627 compounds with an average error of 0.84 log unit. The computational speeds per calculation are a few seconds for CG RISM-HNC and a few minutes for DPD thermodynamic integration.

Viral hepatitis.

Preview The incidence of viral hepatitis in the United States has remained fairly constant for several decades, despite the availability of vaccines and prophylactic measures and improved sanitation nationwide. However, epidemiologic findings, including risk factors for acquisition, are changing, probably because of changes in human ecology and behavior. Dr Becherer discusses this evolution in viral hepatitis and its effect on serologic screening.

Hepatitis C virus.

Preview Research on the hepatitis C virus (HCV) is currently very active, and a continuous stream of advances is coming forth. In this article, the authors present some recent developments in epidemiology and diagnosis, examine the relationship of HCV infection to other medical disorders, and discuss the effectiveness of current drug therapy.

Tratamiento de la infeccion temprana por VIH-1 en adultos / Management of early HIV-1 infection in adults

Si una persona sospecha que esta infectada con el virus de la inmunodeficiencia humana (VIH-1) probablemente buscara la ayuda de un medico general; por lo tanto es importante que los medicos generales esten preparados para atender a tales pacientes. Los autores de este articulo explican como se diferencia la infeccion por VIH-1 de otros trastornos que puedan tener manifestaciones similares, recalcan la importancia de remitir a los pacientes a centros asistenciales especializados y comentan las mejores formas de suprimir la infeccion a largo plazo