Carmofur Exhibits Antimicrobial Activity Against Streptococcus pneumoniae

Background/Objectives:Streptococcus pneumoniae (S. pneumoniae) is a major pathogen causing severe infectious diseases, with an escalating issue of antimicrobial resistance that threatens the efficacy of existing antibiotics. Given the challenges in developing traditional antibiotics, drug repurposing strategies offer a novel approach to address the resistance crisis. This study aims to evaluate the antibacterial and anti-biofilm activities of the approved non-antibiotic anticancer drug carmofur against multidrug-resistant S. pneumoniae, and investigate the mechanism of action, and assess therapeutic potential in vivo. Methods/Results: Antimicrobial tests revealed that carmofur exhibited strong antibacterial activity against multidrug-resistant S. pneumoniae strains, with minimum inhibitory concentrations (MICs) ranging from 0.25 to 1 µg/mL. In the biofilm detection experiments, carmofur not only inhibited the formation of biofilms, but also effectively removed biofilms under high concentration conditions. Mechanistic studies showed that carmofur disrupted bacterial membrane permeability and decreased intracellular ATP levels. Molecular docking and dynamics simulation assays indicated that carmofur could stably bind to thymidylate synthase through hydrogen bonding and hydrophobic interactions, thereby exerting antibacterial effects. Meanwhile, carmofur was able to repress the expression of the thyA gene at the mRNA level. In a mouse infection model, the carmofur treatment group showed a reduction of approximately two log levels in bacterial load in lung tissue and blood, a significant decrease in the levels of inflammatory cytokines TNF-α and IL-6, and an improvement in survival rate to 60%. Conclusions: In summary, carmofur demonstrated significant antibacterial and anti-biofilm activities against multidrug-resistant S. pneumoniae and showed good anti-infective effects in vivo, suggesting its potential clinical application as a therapeutic agent against drug-resistant bacteria.

Breaking the resistance: integrative approaches with novel therapeutics against Klebsiella pneumoniae

Klebsiella pneumoniae is a leading cause of anti-microbial resistance in healthcare-associated infections that have posed a severe threat to neonatal and wider community. The escalating crises of antibiotic resistance have compelled researchers to explore an innovative arsenal beginning from natural resources to chemical modifications in order to overcome the ever-increasing resistance issues. The present review highlights the drug discovery efforts with a special focus on cutting-edge strategies in the hunt for potential drug candidates against MDR/XDR Klebsiella pneumoniae. Nature's bounty constituting plant extracts, essential oils, fungal extracts, etc. holds promising anti-bacterial potential especially when combined with existing antibiotics. Further, enhancing these natural products with synthetic moieties has improved their effectiveness, creating a bridge between the natural and synthetic world. Conversely, the synthetically modified novel scaffolds have been also designed to meticulously target specific sites. Furthermore, we have also elaborated various emerging strategies for broad-spectrum infections caused by K. pneumoniae, which include anti-microbial peptides, nanotechnology, drug repurposing, bacteriophage, photodynamic, and multidrug therapies. This review further addresses the challenges confronted by the research community and the future way forward in the field of drug discovery against multi-resistant bacterial infections.

Drug repurposing against antibiotic resistant bacterial pathogens

The growing prevalence of MDR and XDR bacterial pathogens is posing a critical threat to global health. Traditional antibiotic development paths have encountered significant challenges and are drying up thus necessitating innovative approaches. Drug repurposing, which involves identifying new therapeutic applications for existing drugs, offers a promising alternative to combat resistant pathogens. By leveraging pre-existing safety and efficacy data, drug repurposing accelerates the development of new antimicrobial therapy regimes. This review explores the potential of repurposing existing FDA approved drugs against the ESKAPE and other clinically relevant bacterial pathogens and delves into the identification of suitable drug candidates, their mechanisms of action, and the potential for combination therapies. It also describes clinical trials and patent protection of repurposed drugs, offering perspectives on this evolving realm of therapeutic interventions against drug resistance.

Clinical Characteristics and Predictors of Mortality of Patients with Post-Neurosurgical Meningitis-A 900-Cases Cohort Study

Aim

To express the clinical characteristics of patients with post-neurosurgical meningitis (PNM) and launch a survival analysis to screen mortality predictors.

Methods

A cohort analysis containing more than 70000 patients was evaluated, and all of them received neurosurgical procedure. Clinical and microbial epidemiology, therapy and mortality of PNM patients were reviewed. Multi-variable Cox proportional hazard models were applied to achieve survival analysis.

Results

About 900 PNM patients from 3244 cases were selected for characteristics and survival analysis, the mean age of them was 41 (27-54) years, 516 (57.3%) were men and 384 (42.7%) were women. The 28-day mortality was 12.4% (112 of 900) in patients with PNM. Hypertension, external ventricular drainage (EVD), and lumbar drainage (LD) are mortality predictors for PNM, with a hazard ratio (HR) of 2.641 (95% C.I. 1.563-4.464, P<0.001), 2.196 (95% C.I. 1.317-3.662, P=0.003), and 1.818 (95% C.I. 1.126-2.936, P=0.014). In treatment, the outcome of patients receiving three or more antibiotic combinations is better than that of patients receiving dual-drug combinations.

Conclusion

The mortality of patients with PNM was relatively high, and the risk factors related to 28-days mortality were hypertension, EVD and LD and treatment with three or more antibiotics are much better.

In vitro antibacterial activity of antiretroviral drugs on key commensal bacteria from the human microbiota

Introduction

Antiretroviral therapy has improved life expectancy in HIV-infected patients. However, people living with HIV under antiretroviral therapy are at higher risks of developing chronic complications and acquiring multidrug resistant bacteria than healthy population. These factors have been associated with shifts in gut microbiome composition and immune activation. It is unclear how antiretroviral drugs affect gut microbiota composition, but it has been observed that antiretroviral treatment is not able to fully restore gut health after HIV infection. Additionally, some antiretroviral drugs have shown antibacterial activity suggesting that these drugs could have a direct impact on the human microbiome composition.

Methods

We determined the in vitro antibacterial activity of 16 antiretroviral drugs against a set of key clinically relevant and human commensal bacterial strains.

Results

Our results demonstrate that 5 antiretroviral drugs have in vitro antibacterial activity against gut and vaginal human commensal bacteria. Zidovudine has antibacterial activity against Escherichia coli, Klebsiella pneumoniae and Prevotella bivia, abacavir against Gardnerella vaginalis, efavirenz against G. vaginalis and P. bivia and bictegravir against Enterococcus spp. and G. vaginalis. Moreover, we describe for the first time that elvitegravir has antibacterial activity against G. vaginalis and P. bivia and, most importantly, against vancomycin-resistant Enterococcus spp. and methicillin-resistant Staphylococcus aureus strains with MIC values of 4-16 and 4 µg/mL, respectively showing high level of effectiveness against the tested multidrug-resistant bacteria.

Discussion

Our results underscore that some antiretroviral drugs may influence the human microbiota composition. In addition, we report the potential use of elvitegravir to treat multidrug-resistant Gram-positive bacteria warranting the need of clinical studies to repurpose this antiretroviral drug.

Preliminary Toxicity Evaluation of a Porphyrin Photosensitizer in an Alternative Preclinical Model

In photodynamic therapy (PDT), a photosensitizer (PS) excited with a specific wavelength, and in the presence of oxygen, gives rise to photochemical reactions that lead to cell damage. Over the past few years, larval stages of the G. mellonella moth have proven to be an excellent alternative animal model for in vivo toxicity testing of novel compounds and virulence testing. In this article, we report a series of preliminary studies on G. mellonella larvae to evaluate the photoinduced stress response by a porphyrin (PS) (TPPOH). The tests performed evaluated PS toxicity on larvae and cytotoxicity on hemocytes, both in dark conditions and following PDT. Cellular uptake was also evaluated by fluorescence and flow cytometry. The results obtained demonstrate how the administration of PS and subsequent irradiation of larvae affects not only larvae survival rate, but also immune system cells. It was also possible to verify PS's uptake and uptake kinetics in hemocytes, observing a maximum peak at 8 h. Given the results obtained in these preliminary tests, G. mellonella appears to be a promising model for preclinical PS tests.