A multicenter evaluation of a sample to answer real-time PCR assay for toxigenic C. difficile in symptomatic subjects

We evaluated the performance of the Luminex ARIES® C. difficile Assay on 984 stool specimens prospectively collected from patients being tested for CDI at 4 clinical laboratories in the United States. Results were compared to direct and enriched toxigenic culture. Positive percent agreement (PPA) of the ARIES® C. difficile Assay was 98.1% versus direct toxigenic culture, and sensitivity versus direct plus enriched toxigenic culture was 90.5%. Negative percent agreement (NPA) of the ARIES® C. difficile Assay against direct culture was 92.6%, and specificity versus direct plus enriched toxigenic culture was 95.8%. The ARIES® C. difficile Assay was also compared to the results of routine (molecular, antigen, and/or toxin) methods for C. difficile testing used at each institution. The PPA of the ARIES® C. difficile Assay ranged from 82.9% to 100%. NPA values against these commercial assays ranged from 94.5% to 100%.     

The immunology of Leishmania/HIV co-infection

Leishmaniases are emerging as an important disease in human immunodeficiency virus (HIV)–infected persons living in several sub-tropical and tropical regions around the world, including the Mediterranean. The HIV/AIDS pandemic is spreading at an alarming rate in Africa and the Indian subcontinent, areas with very high prevalence of leishmaniases. The spread of HIV into rural areas and the concomitant spread of leishmaniases to suburban/urban areas have helped maintain the occurrence of Leishmania/HIV co-infection in many parts of the world. The number of cases of Leishmania/HIV co-infection is expected to rise owing to the overlapping geographical distribution of the two infections. In Southwestern Europe, there is also an increasing incidence of Leishmania/HIV co-infection (particularly visceral leishmaniasis) in such countries as France, Italy, Spain and Portugal. Studies suggest that in humans, very complex mechanisms involving dysregulation of host immune responses contribute to Leishmania-mediated immune activation and pathogenesis of HIV. In addition, both HIV-1 and Leishmania infect and multiply within cells of myeloid or lymphoid origin, thereby presenting a perfect recipe for reciprocal modulation of Leishmania and HIV-1-related disease pathogenesis. Importantly, because recovery from leishmaniases is associated with long-term persistence of parasites at the primary infection sites and their draining lymph nodes, there is very real possibility that HIV-mediated immunosuppression (due to CD4⁺ T cell depletion) could lead to reactivation of latent infections (reactivation leishmaniasis) in immunocompromised patients. Here, we present an overview of the immunopathogenesis of Leishmania/HIV co-infection and the implications of this interaction on Leishmania and HIV disease outcome.     

Deprescribing interventions in primary health care mapped to the Behaviour Change Wheel: A scoping review

BackgroundPolypharmacy and inappropriate medication use are an increasing concern. Deprescribing may improve medication use through planned and supervised dose reduction or stopping of medications. As most medication management occurs in primary health care, which is generally described as the first point of access for day-to-day care, deprescribing in primary health care is the focus on this review.ObjectiveThis scoping review aimed to identify and characterize strategies for deprescribing in primary health care and map the strategies to the Behaviour Change Wheel (BCW).MethodsA scoping review was conducted that involved searches of six databases (2002–2018) and reference lists of relevant systematic reviews and included studies. Studies that described and evaluated deprescribing strategies in primary health care were eligible. Two independent reviewers screened articles and completed data charting with charting verified by a third. Deprescribing strategies were mapped to the intervention functions of the BCW and linked to specific Behaviour Change Techniques (BCT).ResultsSearches yielded 6871 citations of which 43 were included. Nineteen studies were randomized, 24 were non-randomized. Studies evaluated deprescribing in terms of medication changes, feasibility, and prescriber/patient perspectives. Deprescribing strategies involved various professionals (physicians, pharmacists, nurses), as well as patients and were generally multifaceted. A wide range of intervention functions were identified, with 41 BCTs mapped to Environmental restructuring, 38 BCTs mapped to Enablement, and 34 BCTs mapped to Persuasion.ConclusionsDeprescribing strategies in primary health care have used a variety of BCTs to address individual professionals (e.g. education) as well as strategies that addressed the practice setting, including support from additional team members (e.g. pharmacists, nurses and patients). Further research is warranted to determine comparative effectiveness of different BCTs, which can help facilitate implementation of deprescribing strategies, thereby reducing polypharmacy, in primary health care.     

Mechanisms of Myocyte Cytotoxicity Induced by the Multikinase Inhibitor Sorafenib

The use of the anticancer multikinase inhibitor sorafenib is associated with cardiac ischemia or infarction and an increase in hypertension. We investigated various mechanisms that might be responsible for its cardiotoxicity in a neonatal rat myocyte model. As measured by lactate dehydrogenase release, sorafenib treatment of myocytes caused dose-dependent damage at therapeutically relevant concentrations. It had been hypothesized that inhibition of RAF1 and BRAF kinases may be responsible for sorafenib-induced cardiotoxicity. However, because sorafenib treatment did not inhibit phosphorylation of ERK (extracellular signal-regulated kinase), it was concluded that sorafenib did not exert its damaging effects through RAF inhibition of the RAF/MEK/ERK kinase cascade. The clinically approved doxorubicin cardioprotective agent dexrazoxane did not protect myocytes from damage. At lower sorafenib concentrations, at least, these results are consistent with sorafenib not being able to induce significant oxidative damage. In conclusion, given the extreme lack of kinase selectivity that sorafenib exhibits, it is likely that inhibition of kinases other than RAF, or combinations of kinases, contributes to the cardiotoxic effects of sorafenib.     

The Dual-Targeted HER1/HER2 Tyrosine Kinase Inhibitor Lapatinib Strongly Potentiates the Cardiac Myocyte-Damaging Effects of Doxorubicin

The anticancer drug lapatinib (Tykerb) is a dual tyrosine kinase inhibitor targeting the HER2 (ERBB2) and EGFR (ERBB1, HER1) pathways that have been shown in clinical trials to display some cardiotoxicity. Because trastuzumab also targets HER2 receptors, the lapatinib/doxorubicin combination provides a good model to probe the mechanism of the increased cardiotoxicity caused by the concurrent use of trastuzumab and doxorubicin. Using a neonatal rat cardiac myocyte model, we have investigated the ability of lapatinib alone and in combination with doxorubicin to damage myocytes. Lapatinib treatment alone only slightly induced myocyte damage. However, doxorubicin-induced myocyte damage was greatly potentiated by the addition of nanomolar lapatinib concentrations. Lapatinib alone treatment decreased phosphorylated ERK (MAPK), which may have, in part, contributed to the increased myocyte damage. As measured by flow cytometry, lapatinib-treated myocytes displayed an increased accumulation of doxorubicin. As lapatinib is a strong inhibitor of several ATP-dependent ABC-type efflux transporters, this likely occurred because lapatinib blocked doxorubicin efflux, thereby increasing intracellular doxorubicin concentrations and, thus, increasing myocyte damage. These results suggest that the clinical use of concurrent doxorubicin and lapatinib should be approached with care due to the possibility of lapatinib increasing doxorubicin cardiotoxicity.     

The lack of target specificity of small molecule anticancer kinase inhibitors is correlated with their ability to damage myocytes in vitro

Many new targeted small molecule anticancer kinase inhibitors are actively being developed. However, the clinical use of some kinase inhibitors has been shown to result in cardiotoxicity. In most cases the mechanisms by which they exert their cardiotoxicity are not well understood. We have used large scale profiling data on 8 FDA-approved tyrosine kinase inhibitors and 10 other kinase inhibitors to a panel of 317 kinases in order to correlate binding constants and kinase inhibitor binding selectivity scores with kinase inhibitor-induced damage to neonatal rat cardiac myocytes. The 18 kinase inhibitors that were the subject of this study were: canertinib, dasatinib, dovitinib, erlotinib, flavopiridol, gefitinib, imatinib, lapatinib, midostaurin, motesanib, pazopanib, sorafenib, staurosporine, sunitinib, tandutinib, tozasertib, vandetanib and vatalanib. The combined tyrosine kinase and serine-threonine kinase selectivity scores were highly correlated with the myocyte-damaging effects of the kinase inhibitors. This result suggests that myocyte damage was due to a lack of target selectivity to binding of both tyrosine kinases and serine-threonine kinases, and was not due to binding to either group specifically. Finally, the strength of kinase inhibitor binding for 290 kinases was examined for correlations with myocyte damage. Kinase inhibitor binding was significantly correlated with myocyte damage for 12 kinases. Thus, myocyte damage may be multifactorial in nature with the inhibition of a number of kinases involved in producing kinase inhibitor-induced myocyte damage.     

Performance of distinct phenotypic methods for carbapenemase detection: The influence of culture media

We evaluated the performance of five phenotypic tests [Modified Hodge Test (MHT); combined-disk test (CDT) using phenylboronic acid, EDTA, and cloxacillin; CarbaNP and CarbAcinetoNP; Blue-Carba, Carbapenembac™ and Carbapenembac Metallo™] for carbapenemase detection in Gram-negative bacilli (GNB). A total of 73 carbapenemase producers and 27 non-carbapenemase producers were tested. All GNB were subcultured onto Müeller-Hinton agar (MHA), MacConkey agar (MAC), and sheep blood agar (SBA). High sensitivity (100%) and specificity (100%) was observed for MHA using CarbaNP, Blue-Carba, and Carbapenembac™. The sensitivity and specificity of CarbaNP (98.6%/100%), Blue-Carba (97.1%/91.0%), and Carbapenembac™ (100%/96.5%) were slightly lower for SBA. In contrast, unacceptable sensitivity rates of CarbaNP (71.1%) and Blue-Carba (66.6%), but not Carbapenembac™ (97.3%), were observed for MAC. The colorimetric methods showed high sensitivity and specificity to detect carbapenemase production from isolates grown on MHA or SBA. However, colonies obtained from MAC must not be tested for carbapenemase detection by colorimetric methods.     

Prevalence,predictors, and consequences of inappropriate empiric antimicrobial therapy for complicated urinary tract and intra-abdominal infections in Winnipeg hospitals

Information on inappropriate empiric antimicrobial therapy (ET) in Canadian hospitals is scarce. All Manitobans 18 years of age and over who were admitted to a hospital in Winnipeg with a complicated urinary tract infection (cUTI) or complicated intra-abdominal infection (cIAI) from January 2006 to December 2014 were eligible for inclusion in this cohort study. The prevalence of inappropriate ET was 11% for cUTI patients and 9% for cIAI patients. The risk of receiving inappropriate ET was higher for older patients (cUTI patients 65 or older had 2-fold increased risk compared to younger patients; odds ratio 2.1, 95% confidence interval 1.3–3.6; this was 1.6 [0.7–3.5] for cIAI patients) and those hospitalized in the previous year: 1.5 (1.0–2.4) in cUTIs and 1.5 (0.6–3.4) in cIAIs. The risk for a hospital stay over 3 weeks was increased for inappropriate ET in cUTI patients, 2.3 (1.4–3.7), but not in cIAI patients, 0.9 (0.4–2.1).     

Pharmacokinetic analysis

Pharmacokinetic analysis is an experimentally determined theory of how a drug behaves when in vivo. Volume of distribution, clearance and terminal half-life are defined. Compartmental modelling is introduced and some relevant graphs are described in this article. Applications of this theory in anaesthesia are considered.