Dynamic Stimulation of Visual Cortex Produces Form Vision in Sighted and Blind Humans.

A visual cortical prosthesis (VCP) has long been proposed as a strategy for restoring useful vision to the blind, under the assumption that visual percepts of small spots of light produced with electrical stimulation of visual cortex (phosphenes) will combine into coherent percepts of visual forms, like pixels on a video screen. We tested an alternative strategy in which shapes were traced on the surface of visual cortex by stimulating electrodes in dynamic sequence. In both sighted and blind participants, dynamic stimulation enabled accurate recognition of letter shapes predicted by the brain's spatial map of the visual world. Forms were presented and recognized rapidly by blind participants, up to 86 forms per minute. These findings demonstrate that a brain prosthetic can produce coherent percepts of visual forms.

Proprioception: A New Era Set in Motion by Emerging Genetic and Bionic Strategies?

The generation of an internal body model and its continuous update is essential in sensorimotor control. Although known to rely on proprioceptive sensory feedback, the underlying mechanism that transforms this sensory feedback into a dynamic body percept remains poorly understood. However, advances in the development of genetic tools for proprioceptive circuit elements, including the sensory receptors, are beginning to offer new and unprecedented leverage to dissect the central pathways responsible for proprioceptive encoding. Simultaneously, new data derived through emerging bionic neural machine-interface technologies reveal clues regarding the relative importance of kinesthetic sensory feedback and insights into the functional proprioceptive substrates that underlie natural motor behaviors.

Practical Guidance for Clinical Microbiology Laboratories: Microbiologic diagnosis of implant-associated infections.

SUMMARYImplant-associated infections (IAIs) pose serious threats to patients and can be associated with significant morbidity and mortality. These infections may be difficult to diagnose due, in part, to biofilm formation on device surfaces, and because even when microbes are found, their clinical significance may be unclear. Despite recent advances in laboratory testing, IAIs remain a diagnostic challenge. From a therapeutic standpoint, many IAIs currently require device removal and prolonged courses of antimicrobial therapy to effect a cure. Therefore, making an accurate diagnosis, defining both the presence of infection and the involved microorganisms, is paramount. The sensitivity of standard microbial culture for IAI diagnosis varies depending on the type of IAI, the specimen analyzed, and the culture technique(s) used. Although IAI-specific culture-based diagnostics have been described, the challenge of culture-negative IAIs remains. Given this, molecular assays, including both nucleic acid amplification tests and next-generation sequencing-based assays, have been used. In this review, an overview of these challenging infections is presented, as well as an approach to their diagnosis from a microbiologic perspective.

Structural Basis of Hydrogenotrophic Methanogenesis.

Most methanogenic archaea use the rudimentary hydrogenotrophic pathway-from CO2 and H2 to methane-as the terminal step of microbial biomass degradation in anoxic habitats. The barely exergonic process that just conserves sufficient energy for a modest lifestyle involves chemically challenging reactions catalyzed by complex enzyme machineries with unique metal-containing cofactors. The basic strategy of the methanogenic energy metabolism is to covalently bind C1 species to the C1 carriers methanofuran, tetrahydromethanopterin, and coenzyme M at different oxidation states. The four reduction reactions from CO2 to methane involve one molybdopterin-based two-electron reduction, two coenzyme F420-based hydride transfers, and one coenzyme F430-based radical process. For energy conservation, one ion-gradient-forming methyl transfer reaction is sufficient, albeit supported by a sophisticated energy-coupling process termed flavin-based electron bifurcation for driving the endergonic CO2 reduction and fixation. Here, we review the knowledge about the structure-based catalytic mechanism of each enzyme of hydrogenotrophic methanogenesis.

Beyond the Timeline: One-year Mortality Trends in Early vs. Late Prosthetic Valve Endocarditis.

Among 302 episodes with prosthetic valve endocarditis (PVE), one-year mortality was 31%. There was no evidence indicating that early-onset PVE within 6 months from valve surgery led to a worse outcome compared to late-onset PVE (21% versus 32%; p=0.126), despite similar redo valve surgeries across both categories.

The use of long-term antibiotics for suppression of bacterial infections.

Suppressive antibiotic therapy is prescribed when a patient has an infection that is presumed to be incurable by a defined course of therapy or source control. The cohort receiving suppressive antibiotic therapy is typically highly comorbid and the infections often involve retained prosthetic material. In part due to a lack of clear guidelines regarding the use of suppressive antibiotics, and in part due to the complex nature of the infections in question, patients are often prescribed suppressive antibiotics for extremely long, if not indefinite, courses. The risks of prolonged antibiotic exposure in this context are not fully characterised, but they include adverse drug effects ranging from mild to severe, the development of antibiotic resistant organisms and perturbations of the gastrointestinal microbiome. In this narrative review we present the available evidence for the use of suppressive antibiotic therapy in four common indications, examine the gaps in the current literature and explore the known and potential risks of this therapy. We also make suggestions for improving the quality of evidence in future studies, particularly by highlighting the need for a standardised term to describe the use of long-courses of antibiotics to suppress hard-to-treat infections.

Prosthetic Joint Infections due to Candida Species: A Multicenter International Study.

BACKGROUND: Prosthetic joint infection (PJI) caused by Candida spp is a severe complication of arthroplasty. We investigated the outcomes of Candida PJI. METHODS: This was a retrospective observational multinational study including patients diagnosed with Candida-related PJI between 2010 and 2021. Treatment outcome was assessed at 2-year follow-up. RESULTS: A total of 269 patients were analyzed. Median age was 73.0 (interquartile range [IQR], 64.0-79.0) years; 46.5% of patients were male and 10.8% were immunosuppressed. Main infection sites were hip (53.0%) and knee (43.1%), and 33.8% patients had fistulas. Surgical procedures included debridement, antibiotics, and implant retention (DAIR) (35.7%), 1-stage exchange (28.3%), and 2-stage exchange (29.0%). Candida spp identified were Candida albicans (55.8%), Candida parapsilosis (29.4%), Candida glabrata (7.8%), and Candida tropicalis (5.6%). Coinfection with bacteria was found in 51.3% of cases. The primary antifungal agents prescribed were azoles (75.8%) and echinocandins (30.9%), administered for a median of 92.0 (IQR, 54.5-181.3) days. Cure was observed in 156 of 269 (58.0%) cases. Treatment failure was associated with age >70 years (OR, 1.811 [95% confidence interval {CI}: 1.079-3.072]), and the use of DAIR (OR, 1.946 [95% CI: 1.157-3.285]). Candida parapsilosis infection was associated with better outcome (OR, 0.546 [95% CI: .305-.958]). Cure rates were significantly different between DAIR versus 1-stage exchange (46.9% vs 67.1%, P = .008) and DAIR versus 2-stage exchange (46.9% vs 69.2%, P = .003), but there was no difference comparing 1- to 2-stage exchanges (P = .777). CONCLUSIONS: Candida PJI prognosis seems poor, with high rate of failure, which does not appear to be linked to immunosuppression, use of azoles, or treatment duration.

How We Approach Suppressive Antibiotic Therapy Following Debridement, Antibiotics, and Implant Retention for Prosthetic Joint Infection.

The optimal treatment of prosthetic joint infection (PJI) remains uncertain. Patients undergoing debridement, antibiotics, and implant retention (DAIR) receive extended antimicrobial treatment, and some experts leave patients at perceived highest risk of relapse on suppressive antibiotic therapy (SAT). In this narrative review, we synthesize the literature concerning the role of SAT to prevent treatment failure following DAIR, attempting to answer 3 key questions: (1) What factors identify patients at highest risk for treatment failure after DAIR (ie, patients with the greatest potential to benefit from SAT), (2) Does SAT reduce the rate of treatment failure after DAIR, and (3) What are the rates of treatment failure and adverse events necessitating treatment discontinuation in patients receiving SAT? We conclude by proposing risk-benefit stratification criteria to guide use of SAT after DAIR for PJI, informed by the limited available literature.

Cutibacterium Species Valvular and Cardiac Device-Related Infective Endocarditis: Contemporary Data From the GAMES Prospective Cohort (2008-2023).

BACKGROUND: Information on infective endocarditis (IE) caused by Cutibacterium spp. is limited and new Duke-International Society for Cardiovascular Infectious Diseases (ISCVID) criteria have not yet been properly assessed. We examined clinical characteristics, outcomes, and performance of diagnostic tests for Cutibacterium valvular and cardiac implantable electronic device-related IE (CIED-IE). METHODS: Data corresponding to all episodes of Cutibacterium IE recorded from 2008 to 2023 in a prospective national cohort including 46 Spanish hospitals were examined. Possible IE cases were reassessed using the new criteria. The sensitivity of blood cultures, valvular and CIED cultures, and polymerase chain reaction of the 16S rRNA gene and sequencing (16SPCR) was evaluated. RESULTS: Of 6692 episodes of IE, 67 (1%) were caused by Cutibacterium spp. with 85% affecting men. Of these, 50 were valve-related (45 prosthetic, 5 native) and 17 CIED-related. The new criteria identified 8 additional cases and reclassified 15 as definite IE. Intracardiac complications (abscess, pseudoaneurysm, perforation, or intracardiac fistula) occurred in 23 of 50 (46%) valvular IE episodes, leading to 18% mortality, and up to 40% mortality if surgery was indicated but could not be performed. All CIED-IE cases underwent device removal and no deaths were recorded. Positive diagnosis rates for blood cultures, valve/device cultures, and 16SPCR were 52%, 70%, and 82%, respectively. CONCLUSIONS: Cutibacterium IE is a rare yet potentially life-threatening condition that warrants a high index of suspicion in men with endovascular prosthetic material. The new Duke-ISCVID criteria and molecular techniques are useful for its diagnosis. Considering a significant complication rate, cardiac surgery and removal of CIEDs play a key role in reducing mortality.

Evaluation of the 2023 Duke-International Society of Cardiovascular Infectious Diseases Criteria in a Multicenter Cohort of Patients With Suspected Infective Endocarditis.

BACKGROUND: Since publication of Duke criteria for infective endocarditis (IE) diagnosis, several modifications have been proposed. We aimed to evaluate the diagnostic performance of the Duke-ISCVID (International Society of Cardiovascular Infectious Diseases) 2023 criteria compared to prior versions from 2000 (Duke-Li 2000) and 2015 (Duke-ESC [European Society for Cardiology] 2015). METHODS: This study was conducted at 2 university hospitals between 2014 and 2022 among patients with suspected IE. A case was classified as IE (final IE diagnosis) by the Endocarditis Team. Sensitivity for each version of the Duke criteria was calculated among patients with confirmed IE based on pathological, surgical, and microbiological data. Specificity for each version of the Duke criteria was calculated among patients with suspected IE for whom IE diagnosis was ruled out. RESULTS: In total, 2132 episodes with suspected IE were included, of which 1101 (52%) had final IE diagnosis. Definite IE by pathologic criteria was found in 285 (13%), 285 (13%), and 345 (16%) patients using the Duke-Li 2000, Duke-ESC 2015, or the Duke-ISCVID 2023 criteria, respectively. IE was excluded by histopathology in 25 (1%) patients. The Duke-ISCVID 2023 clinical criteria showed a higher sensitivity (84%) compared to previous versions (70%). However, specificity of the new clinical criteria was lower (60%) compared to previous versions (74%). CONCLUSIONS: The Duke-ISCVID 2023 criteria led to an increase in sensitivity compared to previous versions. Further studies are needed to evaluate items that could increase sensitivity by reducing the number of IE patients misclassified as possible, but without having detrimental effect on specificity of Duke criteria.