Long-standing evidence indicates that human immunodeficiency virus type 1 (HIV-1) preferentially integrates into a subset of transcriptionally active genes of the host cell genome. However, the reason why the virus selects only certain genes among all transcriptionally active regions in a target cell remains largely unknown. Here we show that HIV-1 integration occurs in the outer shell of the nucleus in close correspondence with the nuclear pore. This region contains a series of cellular genes, which are preferentially targeted by the virus, and characterized by the presence of active transcription chromatin marks before viral infection. In contrast, the virus strongly disfavours the heterochromatic regions in the nuclear lamin-associated domains and other transcriptionally active regions located centrally in the nucleus. Functional viral integrase and the presence of the cellular Nup153 and LEDGF/p75 integration cofactors are indispensable for the peripheral integration of the virus. Once integrated at the nuclear pore, the HIV-1 DNA makes contact with various nucleoporins; this association takes part in the transcriptional regulation of the viral genome. These results indicate that nuclear topography is an essential determinant of the HIV-1 life cycle.
Candidemia has become an important bloodstream infection that is frequently associated with high rates of mortality and morbidity, and its growing incidence is related to complex medical and surgical procedures. We conducted a multicenter study in five tertiary care teaching hospitals in Italy and Spain and evaluated the epidemiology, species distribution, antifungal susceptibilities, and outcomes of candidemia episodes. In the period of 2008 to 2010, 995 episodes of candidemia were identified in these hospitals. The overall incidence of candidemia was 1.55 cases per 1,000 admissions and remained stable during the 3-year analysis. Candida albicans was the leading agent of infection (58.4%), followed by Candida parapsilosis complex (19.5%), Candida tropicalis (9.3%), and Candida glabrata (8.3%). The majority of the candidemia episodes were found in the internal medicine department (49.6%), followed by the surgical ward, the intensive care unit (ICU), and the hemato-oncology ward. Out of 955 patients who were eligible for evaluation, 381 (39.9%) died within 30 days from the onset of candidemia. Important differences in the 30-day mortality rates were noted between institutions: the lowest mortality rate was in the Barcelona hospital, and the highest rate was in the Udine hospital (33.6% versus 51%, respectively; P ؍ 0.0005). Overall, 5.1% of the 955 isolates tested were resistant or susceptible dose dependent (SDD) to fluconazole, with minor differences between the hospitals in Italy and Spain (5.7% versus 3.5%, respectively; P ؍ 0.2). Higher MICs for caspofungin were found, especially with C. parapsilosis complex (MIC 90 , 1 g/ml). Amphotericin B had the lowest MICs. This report shows that candidemia is a significant source of morbidity in Europe, causing a substantial burden of disease and mortality.
Risk factors for invasive fungal infection in patients undergoing orthotopic liver transplantation were examined. Thirty-four of 168 transplants were complicated within 100 days after transplantation by documented invasive fungal infection (Candida species, 28 patients; mycelial fungi, 5; both Candida and Aspergillus species, 1). In the multivariate Cox proportional hazards model, three baseline and two posttransplant variables were independently significant risk factors for infection: level of creatinine (hazard ratio = 1.4), length of transplant operation (HR = 1.2), retransplantation (HR = 3.2), abdominal or intrathoracic reoperations (HR = 2.5), and cytomegalovirus infection (HR = 8.5). Four predictors (creatinine of > 3.0 mg/dL, operative time of > or = 11 h, retransplantation, and early colonization) assessable at the time of transplantation or shortly thereafter were incorporated into a simple predictive model for risk stratification. The risk of invasive fungal infection ranged from 1% in patients with no predictors to 67% in patients with two or more predictors. Strategies to prevent invasive fungal infections after liver transplantation should be targeted to these high-risk groups.
A total of 216 patients (mean age 63.4 ± 18.5 years; 58.3 % males) were included in the study. Of these, 163 (75 %) were admitted to the intensive care unit. Overall 30-day mortality was 54 %. Significantly higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores, dysfunctional organs, and inadequate antifungal therapy were compared in nonsurvivors and survivors. No differences in survivors versus nonsurvivors were found in terms of the time from positive blood culture to initiation of adequate antifungal therapy. Multivariate logistic regression identified inadequate source control, inadequate antifungal therapy, and 1-point increments in the APACHE II score as independent variables associated with a higher 30-day mortality rate.
Low percentages of concomitant candidemia and high mortality rates are documented in IAC. In patients presenting with septic shock, source control is fundamental.
Nuclear bodies (NBs), characterized by the presence of the promyelocytic leukemia (PML) protein, are important components of the nuclear architecture, contributing to genetic and epigenetic control of gene expression. In investigating the mechanisms mediating HIV-1 latency, we determined that silenced but transcriptionally competent HIV-1 proviruses reside in close proximity to PML NBs and that this association inhibits HIV-1 gene expression. PML binds to the latent HIV-1 promoter, which coincides with transcriptionally inactive facultative heterochromatic marks, notably H3K9me2, at the viral genome. PML degradation and NB disruption result in strong activation of viral transcription as well as release of G9a, the major methyltransferase responsible for H3K9me2, and loss of facultative heterochromatin marks from the proviral DNA. Additionally, HIV-1 transcriptional activation requires proviral displacement from PML NBs by active nuclear actin polymerization. Thus, nuclear topology and active gene movement mediate HIV-1 transcriptional regulation and have implications for controlling HIV-1 latency and eradication.
Background The objective of this study was to assess the cumulative incidence of invasive candidiasis (IC) in intensive care units (ICUs) in Europe. Methods A multinational, multicenter, retrospective study was conducted in 23 ICUs in 9 European countries, representing the first phase of the candidemia/intra-abdominal candidiasis in European ICU project (EUCANDICU). Results During the study period, 570 episodes of ICU-acquired IC were observed, with a cumulative incidence of 7.07 episodes per 1000 ICU admissions, with important between-center variability. Separated, non-mutually exclusive cumulative incidences of candidemia and IAC were 5.52 and 1.84 episodes per 1000 ICU admissions, respectively. Crude 30-day mortality was 42%. Age (odds ratio [OR] 1.04 per year, 95% CI 1.02–1.06, p < 0.001), severe hepatic failure (OR 3.25, 95% 1.31–8.08, p 0.011), SOFA score at the onset of IC (OR 1.11 per point, 95% CI 1.04–1.17, p 0.001), and septic shock (OR 2.12, 95% CI 1.24–3.63, p 0.006) were associated with increased 30-day mortality in a secondary, exploratory analysis. Conclusions The cumulative incidence of IC in 23 European ICUs was 7.07 episodes per 1000 ICU admissions. Future in-depth analyses will allow explaining part of the observed between-center variability, with the ultimate aim of helping to improve local infection control and antifungal stewardship projects and interventions.
Background A growing body of observational evidence supports the value of ceftazidime-avibactam (CAZ-AVI) in managing infections caused by carbapenem-resistant Enterobacteriaceae (CRE). Methods We retrospectively analyzed observational data on the use and outcomes of CAZ-AVI therapy for infections caused by KPC-producing K. pneumoniae (KPC-Kp) strains. Multivariate regression analysis was used to identify variables independently associated with 30-day mortality. Results were adjusted for propensity score for receipt of CAZ-AVI combination regimens vs. CAZ-AVI monotherapy. Results The cohort comprised 577 adults with bloodstream infections (BSIs) (n=391) or non-bacteremic infections (nBSIs) involving mainly the urinary tract, lower respiratory tract, intra-abdominal structures. All received treatment with CAZ-AVI alone (n=165) or with one or more other active antimicrobials (n=412). The all-cause mortality rate 30 days after infection onset was 25% (146/577). There was no statistically significant difference in mortality between patients managed with CAZ-AVI alone and those treated with combination regimens (26.1% vs. 25.0%, P=0.79). In multivariate analysis, mortality was positively associated with the presence at infection onset of septic shock (P=0.002), neutropenia (P <0.001), or an INCREMENT score >8 (P=0.01); with LRTI (P=0.04); and with CAZ-AVI dose adjustment for renal function (P=0.01). Mortality was negatively associated with CAZ-AVI administration by prolonged infusion (P=0.006). All associations remained significant after propensity score adjustment. Conclusions CAZ-AVI is an important option for treating serious KPC-Kp infections, even when used alone. Further study is needed to explore the drug’s seemingly more limited efficacy in LRTIs and the potential survival benefits of prolonging CAZ-AVI infusions to 3 hours or more.
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