Eleftherios Mylonakis

As the burden of antimicrobial resistance continues to rise worldwide, the need for novel antimicrobial therapeutics has become increasingly urgent. Machine learning (ML) has emerged as a promising strategy for accelerating antimicrobial peptide discovery; however, experimental characterization remains essential to define the biological properties and broader applicability of ML-optimized peptides. CIT8 is a 13-residue, citropin-based peptide previously developed through ML-optimization with potent antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). Here, we demonstrate that its activity extends to multidrug-resistant Gram-negative pathogens. Among these, CIT8 displayed the most potent activity against Acinetobacter baumannii , maintaining an MIC of 4 μg/mL against 15 of 16 A. baumannii strains tested, including multiple carbapenem-resistant (CRAB) clinical isolates. At 20 μg/mL (5 × MIC), CIT8 reduced an initial population of approximately 5 × 10 ⁷ CFU/mL of exponential-phase A. baumannii to below the limit of detection within 15 min. Consistent with its rapid bactericidal activity, CIT8 induced rapid, dose-dependent membrane depolarization and permeabilization, accompanied by leakage of intracellular ATP. In addition, CIT8 and, even more notably, its D-enantiomer CIT8-D exhibited strong antibiofilm activity while maintaining relatively low mammalian cytotoxicity, with therapeutic indices of >32 for CIT8 in both cell lines and 16.2 and 18.5 for CIT8-D in HaCaT and HKC-8 cells, respectively. Moreover, CIT8 potentiated the bactericidal activity of meropenem against CRAB, with the combination exhibiting bactericidal synergy by time-kill assay. These findings highlight CIT8 as a promising scaffold for further optimization and preclinical evaluation against multidrug-resistant A. baumannii .

1. Candidozyma auris (syn. Candida auris) has emerged as a global health threat owing to its remarkable environmental persistence, rapid transmission in healthcare settings, and multidrug resistanc...

The convergence of artificial intelligence (AI) and antimicrobial pharmacology is creating unprecedented opportunities to accelerate antimicrobial discovery, optimize therapeutic strategies, and reduce the global burden of infectious diseases. A critical determinant of the successful integration of AI into antimicrobial pharmacology is the accurate and interpretable prediction of pharmacokinetic (PK) and pharmacodynamic (PD) properties, including measures such as the minimum inhibitory concentration (MIC), to identify the PK/PD indices and dosing regimens that maximize antimicrobial efficacy while ensuring safety. We review recent developments in AI models for antimicrobial PK/PD and critically examine their performance, interpretability, generalizability, and readiness for clinical translation. We provide a practical framework to help researchers, microbiologists, pharmacologists, and clinicians evaluate the strengths, limitations, and appropriate applications of these emerging approaches. We anticipate that rigorous development, transparent validation, and thoughtful implementation of AI-driven PK/PD models will accelerate antimicrobial discovery, optimize precision dosing, and ultimately improve patient outcomes.

Antibiotic resistance threatens the effectiveness of conventional antimicrobial agents, underscoring the need for host-directed therapies that enhance immune defense. Here, we present a cross-species discovery pipeline that couples a Caenorhabditis elegans–Staphylococcus aureus liquid-based infection screen with mammalian mechanistic validation to identify small-molecule immunomodulators. Using six C. elegans innate immunity reporter strains, we identified a known small molecule, SKI-II, as a previously unrecognized host-protective compound that activates the C. elegans SKN-1/Nrf2 oxidative-stress pathway. In mouse RAW264.7 macrophages, SKI-II binds to the ATPase pocket of VCP (Valosin-Containing Protein), activating the PERK-dependent (Protein kinase R [PKR]-like Endoplasmic Reticulum Kinase) Nrf2 signaling regulation axis that reduces the levels of pathogenic ROS (reactive oxygen species). SKI-II treatment also promotes macrophage M1 polarization and a mitochondrial metabolic shift. This work identifies VCP as a druggable node for host-directed immunomodulation and highlights SKI-II as a prototype small molecule that boosts host tolerance to infection, thereby validating our C. elegans -based screening platform for discovering immunomodulators active in mammalian systems. IMPORTANCE: Enhancing host immunity is a promising strategy to combat S. aureus infection, particularly multidrug-resistant strains. In this study, we applied a C. elegans liquid-based infection screening model to identify the immunomodulatory compound SKI-II. We demonstrate that SKI-II protects against S. aureus infection in both nematodes and mouse macrophages by regulating host oxidative stress pathways rather than directly targeting the pathogen. We reveal a regulatory circuit in which VCP functions as a central node controlling cellular ROS responses and activating the downstream PERK-dependent Nrf2 antioxidant signaling pathway. These findings advance our understanding of host cellular responses to bacterial infection and highlight VCP as a druggable target for host-directed therapeutic strategies against infectious diseases.

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease in older adults, driving hepatic decompensation and cardiovascular mortality. Randomised trial data on glucagon-like peptide-1 (GLP-1) receptor agonist (GLP-1 RA) therapy remain limited. Methods: We conducted a retrospective cohort study using TriNetX US Collaborative Network. Adults 65 years or older with MASLD were identified by codes for fatty liver disease or steatohepatitis plus one cardiometabolic risk factor. We excluded liver transplant and other liver disease causes. Using a new-user, intention-to-treat design with 1:1 propensity-score matching, we compared GLP-1 RA initiators with unexposed patients. Outcomes were hepatic decompensation, hospitalisation, mortality and major adverse cardiovascular events (MACE), assessed 90 days to 10 years after index. Sensitivity analyses restricted follow-up to 1–10 years, excluded tirzepatide or began follow-up on day 1. Findings: We identified 44 196 GLP-1 RA initiators and 384 672 unexposed patients. After matching, 43 930 remained per cohort (mean age 71.8 years; 62.0% female), with standardised mean differences below 0.1. GLP-1 RA use was linked to lower hazards of hepatic decompensation (hazard ratios [HR] 0.72, 95% confidence intervals [CI] 0.66–0.79), mortality (HR 0.55, 0.52–0.58) and hospitalisation (HR 0.95, 0.93–0.97). MACE showed no reduction (HR 0.98, 0.92–1.04). Osteoporosis without fracture and retinopathy were more frequent; pancreatitis, sarcopenia and fracture did not differ. GI events occurred more often as first events. Sensitivity analyses confirmed results for decompensation, hospitalisation and mortality. Interpretation: In older adults with MASLD, GLP-1 RA initiation was linked to lower risks of hepatic decompensation, hospitalisation and mortality, with higher rates of selected adverse events.

Objective: The prevalence of major pulmonary complications of systemic lupus erythematosus (SLE) such as interstitial lung disease (ILD), pulmonary arterial hypertension (PAH), diffuse alveolar hemorrhage (DAH), shrinking lung syndrome (SLS), and acute lupus pneumonitis (LP) has been less studied. We aimed to calculate the prevalence of those complications in patients with SLE. Methods: We searched PubMed and Embase for observational studies evaluating major pulmonary complications in individuals with SLE. We calculated the pooled prevalence of interstitial lung abnormalities (ILAs/radiographic ILD) and clinical ILD, as well as PAH, DAH, SLS, and LP among individuals with SLE with data available from eligible prospective and retrospective studies. We used 95% confidence intervals (CIs). Our study was registered on PROSPERO (CRD420251118717). Results: From 1,347 abstracts, we identified 40 studies with relevant data. We estimated that the pooled prevalence of ILAs was 12.39% (95% CI 9.68%–15.36%) whereas for PAH, LP, DAH, and SLS they were 2.30% (95% CI 1.84%–2.81%), 3.05% (95% CI 1.53%–4.85%), 1.37% (95% CI 0.70%–2.22%), and 1.25% (95% CI 0.05%–2.19%), respectively. Regarding clinical ILD, the pooled prevalence was 2.92% (95% CI 1.50%–4.46%). As for ILD radiographic patterns, the prevalence of nonspecific interstitial pneumonia (NSIP) and usual interstitial pneumonia (UIP) was 52.47% (95% CI 37.36%–67.37%) and 12.09% (95% CI 5.01%–21.24%), respectively, among patients with SLE with ILD. Conclusion: Major pulmonary complications in SLE are more prevalent than previously recognized, especially radiographic findings of ILAs. ILD with an NSIP pattern is the most common, although it is reassuring that DAH, SLS, and LP remain relatively rare. Targeted screening with high‐resolution computed tomography or right heart catheterization for ILD and PAH, respectively, along with timely intervention in high‐risk or symptomatic patients could improve outcomes. image

SUMMARY: Persistent Staphylococcus aureus infections pose a major therapeutic challenge due to the formation of metabolically dormant persister cells that survive antibiotic exposure without acquiring genetic resistance. Despite their potent bactericidal activity, aminoglycosides fail against these persisters due to their reliance on energy-dependent uptake driven by the proton motive force (PMF). This review synthesizes emerging strategies designed to overcome this critical bottleneck. Metabolic stimulation using specific carbon sources or PMF-modulating agents reactivates membrane energetics, thereby restoring aminoglycoside uptake in dormant cells. Membrane-targeting adjuvants bypass PMF altogether, enabling antibiotic entry via biophysical remodeling and disruption of the lipid bilayer. Additionally, we discuss rationally engineered aminoglycoside hybrids, such as peptide-conjugated variants, that achieve self-directed, energy-independent penetration while preserving ribosomal targeting. Collectively, these approaches highlight that aminoglycoside failure against S. aureus persisters can be a modifiable physiological limitation rather than an issue of intrinsic resistance. The convergence of metabolic and membrane-based potentiation underscores the therapeutic potential of combinatorial regimens tailored to the unique bioenergetic state of persisters. Their clinical translation, combined with efforts to address toxicity, may transform the treatment landscape of recalcitrant S. aureus infections and mitigate the risk of relapse.

Purpose: Casirivimab and imdevimab (CAS+IMD) has been shown to improve clinical outcomes (death/mechanical ventilation) in seronegative hospitalized patients with COVID-19. The objective of the current analysis was to assess whether time to administration of CAS+IMD, from the start of COVID-19 symptoms, influenced these outcomes. Patients and Methods: This was a post hoc analysis of Study 2066 (conducted between 10 June 2020 and 9 April 2021), a Phase I/II/III trial investigating the safety and efficacy of CAS+IMD (single intravenous dose) vs placebo in hospitalized adult patients with COVID-19. The primary outcome in this analysis was death or mechanical ventilation. Two populations of patients were assessed: efficacy (n = 738) and exploratory (full analysis set-exploratory data analysis [FAS-EDA]; n = 1115). Time to administration was defined as the number of days of COVID-19 prior to treatment, 4 days being the first quartile, which was considered early treatment administration of CAS+IMD. Results: Odds of death or mechanical ventilation were higher in those aged 50– 70 years (odds ratio [OR]: 2.98; 95% confidence interval [CI], 1.62– 5.91; P = 0.0008) and > 70 years (OR: 4.50; 95% CI, 2.45– 8.96; P = 0.001) than those aged < 50 years. Overall, patients who received CAS+IMD < 4 days after first COVID-19 symptoms had better outcomes than patients receiving CAS+IMD ≥ 4 days, on adjusted analyses (efficacy OR: 0.42; 95% CI, 0.20– 0.80; P = 0.0122; FAS-EDA OR: 0.63; 95% CI, 0.38– 1.01; P = 0.0664). These differences were most notable in those aged 50– 70 years (OR: 0.24; 95% CI, 0.05– 0.70; P = 0.0219). Conclusion: Early monoclonal antibody treatment is associated with better outcomes in hospitalized patients with severe COVID-19.