Adherence to 2015 ESC Guidelines for the Treatment of Infective Endocarditis: A Retrospective Multicentre Study (LEIOT Study)

Background: Infective endocarditis (IE) is still a severe disease with elevated morbidity and mortality. Nevertheless, the last European guidelines (GL) date back to 2015, and a recent survey described a diffuse suboptimal adherence to their recommendations. Here, we described a real-life scenario about adherence to IE treatment GL. Methods: This was a retrospective, multicentric, case–control study. All the cases of IE admitted to our wards from 2016 to 2020 were enrolled. Patients were divided into two groups, according to the non-adherence (group A, cases) or adherence (group B, controls) to 2015 ESC guidelines. Only targeted treatments were considered. Groups were compared for demographic, clinical, microbiological, and laboratory data and outcome. As a post hoc analysis, we analysed the characteristics of deviations from the guidelines and how these deviations affected mortality. Results: A total of 246 patients were enrolled, with 128 (52%) in group A and 118 (48%) in group B. Groups were homogeneous except for aetiologies: staphylococcal and blood-culture-negative IE were more frequent in group A, while streptococcal and enterococcal IE were more frequent in group B (p < 0.001). In-hospital mortality was comparable in the two groups. The most frequent causes of deviations from the guidelines were use of daptomycin, in addition to standard treatments and the missing administration of rifampin or gentamycin. Conclusions: Adherence to 2015 ESC guidelines was limited but it did not affect mortality.

Burden of Community-Acquired Pneumonia and Unmet Clinical Needs

Community-acquired pneumonia (CAP) is the leading cause of death among infectious diseases and an important health problem, having considerable implications for healthcare systems worldwide. Despite important advances in prevention through vaccines, new rapid diagnostic tests and antibiotics, CAP management still has significant drawbacks. Mortality remains very high in severely ill patients presenting with respiratory failure or shock but is also high in the elderly. Even after a CAP episode, higher risk of death remains during a long period, a risk mainly driven by inflammation and patient-related co-morbidities. CAP microbiology has been altered by new molecular diagnostic tests that have turned viruses into the most identified pathogens, notwithstanding uncertainties about the specific role of each virus in CAP pathogenesis. Pneumococcal vaccines also impacted CAP etiology and thus had changed Streptococcus pneumoniae circulating serotypes. Pathogens from specific regions should also be kept in mind when treating CAP. New antibiotics for CAP treatment were not tested in severely ill patients and focused on multidrug-resistant pathogens that are unrelated to CAP, limiting their general use and indications for intensive care unit (ICU) patients. Similarly, CAP management could be personalized through the use of adjunctive therapies that showed outcome improvements in particular patient groups. Although pneumococcal vaccination was only convincingly shown to reduce invasive pneumococcal disease, with a less significant effect in pneumococcal CAP, it remains the best therapeutic intervention to prevent bacterial CAP. Further research in CAP is needed to reduce its population impact and improve individual outcomes.

Management of ventilator-associated pneumonia (VAP) caused by resistant gram-negative bacteria: which is the best strategy to treat?

Introduction: Treatment of ventilator-associated pneumonia (VAP) is a major challenge. The increase in multi-drug resistant bacteria has not been accompanied by the validation of new drugs, or by any new antimicrobial strategies to exploit the available agents. VAP due to Gram-negative bacteria has increased mortality, both due to the resistant pathogens themselves and due to inappropriate treatment. Local epidemiology, patients' characteristics and clinical responses provide the most important information for therapeutic decision-making. Moreover, data on VAP therapy due to resistant bacteria are lacking, and the choice of treatment is often based on clinical practice and individual experience. Areas covered: This review summarizes the strategies available for treating the three most prevalent resistant Gram-negative organisms causing VAP: Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacteriaceae. The review covers the results of a Pubmed search, clinical practice guidelines and reviews, and the authors' experience. Expert opinion: The existing evidence focuses on bloodstream infections or other sites rather than pneumonia and there are no recommendations for the treatment of VAP by multi-drug resistant Gram-negative bacteria, especially for combination regimens. The approval of new drugs is needed to provide effective and safe alternatives for treating carbapenemase-producing strains. Precision medicine and personalized approach are also fundamental in future research.

Mitral Valve Infective Endocarditis due to Streptococcus pyogenes: A Case Report

Infective endocarditis (IE) due to group A β-hemolytic streptococcus (Streptococcus pyogenes) has rarely been reported in the literature. We herein report a Streptococcus pyogenes native mitral valve endocarditis in a young patient and a review of the literature. The patient had a native mitral valve endocarditis with vegetation; his hemodynamic stability and a short course of antibiotic treatment prevented urgent surgery on the mitral valve. He was previously treated with cefixime and azithromycin for four days and then, upon hospital admission, with vancomycin plus amoxicillin-clavulanate. After the diagnosis of IE due to Streptococcus pyogenes, treatment with gentamicin (3 mg/kg daily) and ampicillin (12 g/day) was implemented. The patient underwent weekly echocardiographic evaluations during antibiotic treatment to document the resolution of the vegetations. He was discharged to home in good clinical conditions after a four-week course of antibiotic treatment.

Beyond the gut bacterial microbiota: The gut virome

The gastrointestinal tract is colonized with a highly different population of bacterial, viral, ad fungal species; viruses are reported to be dominant. The composition of gut virome is closely related to dietary habits and surrounding environment. Host and their intestinal microbes live in a dynamic equilibrium and viruses stimulate a low degree of immune responses without causing symptoms (host tolerance). However, intestinal phages could lead to a rupture of eubiosis and may contribute to the shift from health to disease in humans and animals. Viral nucleic acids and other products of lysis of bacteria serve as pathogen‐associated molecular patterns (PAMPs) and could trigger specific inflammatory modulations. At the same time, phages could elicit innate antiviral immune responses. Toll‐like receptors (TLRs) operated as innate antiviral immune sensors and their activation triggers signaling cascades that lead to inflammatory response. J. Med. Virol. 88:1467–1472, 2016. © 2016 Wiley Periodicals, Inc.

Understanding the Mechanisms of Fibrogenesis in HIV/HCV-Coinfected Patients: Implications for Clinical Practice

HIV/HCV coinfection is associated with accelerated progressive liver disease. Understanding the pathogenesis of liver fibrosis remains crucial to improving the global management of this patient population. This review will mainly focus on the mechanisms involved in the faster progression of liver fibrosis seen in HIV/HCV coinfection, which is caused by a multiplicity of complex factors including virus features, the immune system, interactions between viruses and the immune response, the direct effects of HIV on hepatocytes, fibrinogenetic/inflammatory mediators, microbial translocation, and metabolic abnormalities. The direct role of viruses as well as chronic inflammation, deterioration of immune status, and the harmful effect of antiretroviral agents may all concur to produce dyslipidemia and insulin resistance. Metabolic abnormalities play an important role in the genesis of hepatic steatosis, which is closely linked to liver fibrosis progression. There is also a link between immunologic and metabolic abnormalities: increased expression of leptin and reduced expression of adiponectin seems to be associated with advanced hepatic injury. New antifibrotic strategies are outlined. Ultimately, sustained virological response to hepatitis C therapy is associated with liver fibrosis regression in patients with HIV/HCV coinfection.

Blood flow cytometry in Sézary syndrome: new insights on prognostic relevance and immunophenotypic changes during follow-up

OBJECTIVES

Sézary syndrome (SS) is characterized by erythroderma, generalized lymphadenopathy, and the presence of circulating atypical lymphocytes, which are difficult to identify by morphologic data.

METHODS

We revised our series of 107 patients in an attempt to better define the phenotypic aberrancies in blood at diagnosis and the immunophenotypic stability over time detected by flow cytometry. Polymerase chain reaction assay was also used to study CD26/dipeptidyl peptidase IV (DPPIV) gene methylation.

RESULTS

The most common aberrancies were represented by the lack of CD26 (96/107) or CD38 (101/107) expression and the presence of a "dim" CD3, CD4, or CD2 population. There was a high variability in CD7 expression. In total, 31% of the patients had phenotypical heterogeneity in CD26 and CD7 expression at diagnosis. The phenotype was stable over time in 73 of 95 patients with available follow-up data, while 22 of 95 patients developed changes in CD26, CD7, or CD2 expression. CD4+CD26- SS showed hypermethylation of the CpG islands for the promoter region of CD26/DPPIV. Multivariate analysis showed that CD26 expression is a favorable prognostic factor (hazard ratio, 2.94; P = .045).

CONCLUSIONS

We confirm the relevance of CD26 negativity in SS diagnosis and monitoring. Nevertheless, the presence of rare CD26+ cases suggests that a multiparameter flow cytometry approach should be used. Changes in methylation profile could account for phenotypical heterogeneity.

Impact of the biochemical assay for serum creatinine measurement on the individual carboplatin dosing: a prospective study

We previously developed a formula to estimate the individual carboplatin clearance (CL) based on serum creatinine (Scr) determined by an enzymatic assay using creatinine amidohydrolase. An analytical comparison had shown systematic differences between this method and the commonly used Jaffé method (with Jaffé Scr (in microM)=1.08 x enzymatic Scr+1.6, as regression equation). We performed a pharmacokinetic prospective clinical study using the Jaffé assay to evaluate the impact of the method used for Scr measurement on the prediction of the carboplatin CL. In forty patients, carboplatin dosing was performed according to the Chatelut formula where the serum creatinine level was corrected according to the above equation. The population pharmacokinetics of carboplatin were analysed using the NONMEM program to determine the individual carboplatin CL from a limited sampling strategy. Thanks to the correction of the Jaffé Scr, no significant difference was observed between the administered and the optimal dose. In contrast, if no correction of the Scr was done, the patients would have been significantly under-dosed. Moreover, a covariate analysis using NONMEM gave a very consistent result showing that Scr should be decreased by 11.6% when the Jaffé value is used within the Chatelut equation. This study confirmed that differences in the Scr assay has consequences with regard to carboplatin dosing. The correction we propose for Scr obtained by the Jaffé method may help to standardise clinical practice.

Purification and Characterization of Chloroplastic NADP-Isocitrate Dehydrogenase from Mixotrophic Tobacco Cells (Comparison with the Cytosolic Isoenzyme)

Green, mixotrophic tobacco (Nicotiana tabacum) cell cultures in the exponential growth phase were found to have two clearly distinguishable NADP-isocitrate dehydrogenase (ICDH; EC 1.1.1.42) isoenzymes. Their elution behavior during anion-exchange column chromatography was similar to that described previously for the cytosolic (ICDH1) and chloroplastic (ICDH2) enzymes from pea (Pisum sativum) leaves. ICDH2 was absent in etiolated tobacco cell suspensions and appeared during the greening process. Both isoforms were purified to apparent electrophoretic homogeneity by ammonium sulfate fractionation and anion-exchange and affinity chromatography. The isoenzymes were separated on a DEAE-Sephacel column, but the most effective step was a Matrex Red-A column, which enabled an overall purification of 833- and 1328-fold for ICDH1 and ICDH2, respectively. Polyclonal antibodies were raised against each isoform. The ICDH2-specific antibody was used to localize tobacco leaf ICDH2 in situ by an immunogold labeling technique. The enzyme was found largely, if not exclusively, in the chloroplasts of green leaves. ICDH1 and ICDH2 were shown to have apparent native molecular weights of 117,000 and 136,000, respectively, and to consist of identical, 48.5-kD subunits. Similar apparent Km values for NADP, D(+)isocitrate, and Mg2+ were found for the two enzymes when assayed with Mg2+ as the metal cofactor.

Localized conversion in Streptococcus pneumoniae recombination: heteroduplex preference

In pneumococcal transformation the frequency of recombinants between point mutations is generally proportional to distance. We have recently described an aberrant marker in the amiA locus that appeared to enhance recombination frequency when crossed with any other allele of this gene. The hyperrecombination that we have observed in two-point crosses could be explained by two hypotheses: the aberrant marker induces frequent crossovers in its vicinity or the mutant is converted to wild type. In this report we present evidence showing that, in suitable three-point crosses, this hyperrecombination does not modify the recombination frequency between outside markers, suggesting that a conversion occurs at the site of this mutation. To estimate the length over which this event occurs, we isolated very closely linked markers and used them in two-point crosses. It appears that the conversion system removes only a few base pairs (from three to 27) around the aberrant marker. This conversion process is quite different from the mismatch-repair system controlled by hex genes in pneumococcus, which involves several thousand base pairs. Moreover, we have constructed artificial heteroduplexes using separated DNA strands. It appears that only one of the two heteroduplexes is specifically converted. The conversion system acts upon 5'..ATTAAT..3'/3'.. TAAGTA..5'. A possible role of the palindrome resulting from the mutation is discussed.