Molecular characterization of resistance to rifampicin in clinical isolates of Neisseria meningitidis

Among 3904 meningococcal isolates collected between October 2002 and June 2007 by the French Meningococcal Reference Centre, eight (0.20%) were resistant to rifampicin (Rif-R; MIC >1 mg/L) and 27 (0.69%) were intermediate-resistant to rifampicin (Rif-I; MICs between 0.38 mg/L and 1 mg/L) according to the E-test method. The MICs determined by agar dilution were lower, eliminating the E-test intermediate category. All Rif-R isolates had mutations in the rpoB gene, resulting in substitutions at or near amino acid position 552, which were absent in non-resistant isolates. These data suggest that a rifampicin clinical breakpoint of 1.0 mg/L should be adopted for Neisseria meningitidis .     

Plasma dilution improves cognition and attenuates neuroinflammation in old mice

Our recent study has established that young blood factors are not causal, nor necessary, for the systemic rejuvenation of mammalian tissues. Instead, a procedure referred to as neutral blood exchange (NBE) that resets signaling milieu to a pro-regenerative state through dilution of old plasma, enhanced the health and repair of the muscle and liver, and promoted better hippocampal neurogenesis in 2-year-old mice (Mehdipour et al., Aging 12:8790–8819, 2020). Here we expand the rejuvenative phenotypes of NBE, focusing on the brain. Namely, our results demonstrate that old mice perform much better in novel object and novel texture (whisker discrimination) tests after a single NBE, which is accompanied by reduced neuroinflammation (less-activated CD68⁺ microglia). Evidence against attenuation/dilution of peripheral senescence-associated secretory phenotype (SASP) as the main mechanism behind NBE was that the senolytic ABT 263 had limited effects on neuroinflammation and did not enhance hippocampal neurogenesis in the old mice. Interestingly, peripherally acting ABT 263 and NBE both diminished SA-βGal signal in the old brain, demonstrating that peripheral senescence propagates to the brain, but NBE was more robustly rejuvenative than ABT 263, suggesting that rejuvenation was not simply by reducing senescence. Explaining the mechanism of the positive effects of NBE on the brain, our comparative proteomics analysis demonstrated that dilution of old blood plasma yields an increase in the determinants of brain maintenance and repair in mice and in people. These findings confirm the paradigm of rejuvenation through dilution of age-elevated systemic factors and extrapolate it to brain health and function.

     

Ocular dominance plasticity is stably maintained in the absence of alpha calcium calmodulin kinase II (alphaCaMKII) autophosphorylation

The molecule alpha calcium calmodulin kinase II (alphaCaMKII) is known to play a fundamental role in the induction of many forms of synaptic plasticity. A major theory of alphaCaMKII function proposes that autophosphorylation of the molecule mediates not only the induction but also the maintenance of synaptic plasticity. To test this hypothesis, we assessed ocular dominance plasticity in genetically engineered mice that carry a mutation preventing autophosphorylation of alphaCaMKII. These mutant mice are deficient in plasticity after monocular deprivation, but a sufficiently long period of monocular deprivation will induce ocular dominance plasticity. After induction of ocular dominance plasticity, the stability of the induced changes was assayed after binocular deprivation. Plasticity in homozygous mutant animals was as stable as that measured in WT littermates; also, response characteristics did not differ between the two groups. Our results suggest that alphaCaMKII autophosphorylation is required for the induction of ocular dominance plasticity but is not needed for its stable maintenance thereafter.     

Usefulness of the PARIS Score to Evaluate the Ischemic-hemorrhagic Net Benefit With Ticagrelor and Prasugrel After an Acute Coronary Syndrome

Introduction and objectives

The PARIS score allows combined stratification of ischemic and hemorrhagic risk in patients with ischemic heart disease treated with coronary stenting and dual antiplatelet therapy (DAPT). Its usefulness in patients with acute coronary syndrome (ACS) treated with ticagrelor or prasugrel is unknown. We investigated this issue in an international registry.

New Innovations in the Treatment of PJI and Biofilms—Clinical and Preclinical Topics

Purpose of Review

Periprosthetic joint infection (PJI) is a devastating complication after total joint replacement. A main source for antibiotic tolerance and treatment failure is bacterial production of biofilm—a resilient barrier against antibiotics, immune system, and mechanical debridement. The purpose of this review is to explore some novel approaches to treat PJI and biofilm-related infections.

Recent Findings

Innovative treatment strategies of bacterial and biofilm infections revolve around (a) augmenting current therapies, such as improving the delivery and efficiency of conventional antibiotics and enhancing the efficacy of antiseptics and (b) administrating completely new therapeutic modalities, such as using immunotherapy, nanoparticles, lytic bacteriophages, photodynamic therapy, novel antibiotics, and antimicrobial peptides.

Summary

Several promising treatment strategies for PJI are available to be tested further. The next requirement for most of the novel treatments is reproducing their effects in clinically representative animal models of PJI against clinical isolates of relevant bacteria.

     

Diffusion-weighted magnetic resonance enterography for prediction of response to tumor necrosis factor inhibitors in stricturing Crohn’s disease

Background and aims

Distinguishing between fibrotic and inflammatory strictures in Crohn’s disease (CD) is still challenging. The capacity of diffusion-weighted (DWI) magnetic resonance (MRE) to identify intestinal fibrosis was recently demonstrated; however, the therapeutic implications of this association have never been evaluated. The aim of the current study was to identify imaging features, including DWI, which can predict response to anti-inflammatory treatment in patients with stricturing CD.

Methods

Consecutive CD patients with intestinal strictures that initiated treatment with anti-tumor necrosis alpha (anti-TNF) between June 2012 and April 2017 with MRE adjacent to treatment onset were retrospectively collected. The primary outcome was treatment failure, defined as drug discontinuation, CD-related surgery, or endoscopic dilatation of the stricture. Clinical, demographic, and imaging data were compared between patients who did and did not develop treatment failure within 12 months of anti-TNF treatment initiation.

Results

A total of 21 patients were included in the study; 9/21 (42.8%) developed treatment failure. None of the clinical/demographic parameters were associated with the risk of treatment failure. Among imaging parameters, only ADC value (< 1 × 10⁻³ mm²/s) was significantly associated with the risk of treatment failure (AUC = 0.81, 66% vs. 0%, p = 0.015).

Conclusions

Our results suggest that ADC value on DWI MRE may predict the risk of treatment failure in stricturing CD. If replicated in larger studies, these results may guide therapeutic decisions and suggest avoiding anti-TNF treatment.