Repositioning of antidepressant drugs and synergistic effect with ciprofloxacin against multidrug-resistant bacteria

Potential activity of paroxetine alone and associated with oxacillin as an alternative to prevent Staphylococcus aureus biofilm formation in catheters

Biofilm formation, especially in medical devices, is a pertinent factor in the virulence of Staphylococcus aureus, and is known to increase morbidity, mortality, and costs. We evaluated the activity of paroxetine, a selective serotonin reuptake inhibitor, alone and associated with oxacillin, a β-lactam antibacterial, against S. aureus biofilms, as well as verified its potential application as a preventive agent against biofilm formation in catheters. The tests were performed against mature and developing biofilms of methicillin-sensitive and -resistant S. aureus using the thiazolyl blue tetrazolium bromide reduction assay. The prevention of biofilm formation in catheters was investigated by counting colony-forming units, and scanning electron microscopy was also performed. Paroxetine caused a significant reduction in cell viability in biofilms, and when associated with oxacillin, significance was verified. Paroxetine alone and associated with oxacillin showed potential for preventing the formation of S. aureus biofilms in peripheral venous catheters, demonstrated by scanning electron microscopy, reaching inhibition of 94.94% in colony-forming units per mL. Paroxetine demonstrated promising potential against S. aureus biofilms in vitro, indicating the possibility of application as a protective agent against the formation of S. aureus biofilms in catheters.

Repurposing of paroxetine and fluoxetine for their antibacterial effects against clinical Pseudomonas aeruginosa isolates in Egypt

Background

Drug repositioning has emerged as a promising strategy for assessing its antimicrobial efficacy in treating infectious diseases.

Methods

Seventy-five samples were collected and investigated for the presence of Pseudomonas aeruginosa. Antibiotic resistance, hemolytic activity, twitching motility, and biofilm formation were assessed. lasI and lasR genes were detected using conventional PCR. Minimum inhibitory concentrations of paroxetine, fluoxetine, and levofloxacin were determined by broth micro-dilution. The fractional inhibitory concentration index was calculated to assess the interaction between fluoxetine/levofloxacin and paroxetine/levofloxacin combinations. Half the MIC values of the drugs were selected for inhibitory effect assessment for virulence factors. Antibacterial and healing effects of fluoxetine were investigated on 30 male albino rats using a digital camera, bacterial count, and histological examination.

Results

Our 25 P. aeruginosa isolates were highly drug-resistant. 80%, 92%, and 80% of isolates were positive for twitching motility, hemolysis, and biofilm formation, respectively. 92% of isolates were positive for lasI gene and 96% for lasR gene. MICs of fluoxetine and paroxetine ranged from 32 to 512 µg/mL and MICs of levofloxacin ranged from 1 to 256 µg/mL. A synergistic outcome was observed in both combinations. Biofilm formation, twitching motility, and hemolysis were inhibited by paroxetine and fluoxetine in the majority of isolates. Fluoxetine/levofloxacin and paroxetine/levofloxacin combinations inhibited twitching motility, hemolysis, and biofilm formation in all isolates. Enhanced wound healing was observed in rats treated with fluoxetine and levofloxacin, with the fluoxetine/levofloxacin combination group demonstrating the most significant wound-healing effect. Bacterial count decreased in rats treated with levofloxacin, fluoxetine, and the levofloxacin/fluoxetine combination. Histological examination revealed higher wound healing in the levofloxacin-treated group than the fluoxetine group, and the combination treatment group displayed the fastest rate of wound healing.

Conclusions

Paroxetine and fluoxetine showed considerable antibacterial inhibitory effects against multi-drug resistant P. aeruginosa isolates. Fluoxetine showed significant improvement in anti-inflammatory effects and wound healing. To the best of our knowledge, this is the first Egyptian study to investigate the repurposing of paroxetine and fluoxetine as antibacterial agents. Further studies are needed to investigate their applicability as antibacterial agents as single agents or in combination with other antibiotics.

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.

Potential Synergy of Fluoxetine and Antibacterial Agents Against Skin and Soft Tissue Pathogens and Drug-Resistant Organisms

Background/Objectives: The feasibility of repurposing selective serotonin reuptake inhibitors as adjunctive antibacterial agents is an area of current investigation. We sought to evaluate if fluoxetine will achieve synergistic killing with relevant antibacterial drugs against skin and soft tissue pathogens and multidrug-resistant pathogens. Methods: The MIC of fluoxetine was determined using broth microdilution for a diverse isolate collection of 21 organisms. Checkerboard experiments were then conducted using fluoxetine and clinically relevant antibacterial drugs. If fluoxetine and an anti-infective agent achieved synergy denoted by a fractional inhibitory concentration index ≤ 0.5, then the combination was further evaluated in 24 h time-killing experiments. Synergy in time-killing experiments was defined as a ≥2 log10 CFU/mL reduction in fluoxetine combined with an antibacterial agent at any point in the experiment in comparison to whichever agent in the combination resulted in the lowest bacterial counts individually. Results: The fluoxetine MICs ranged from 64 to 128 mcg/mL for Gram-positive isolates and 8-512 mcg/mL for Gram-negative organisms. Against Gram-positive isolates, vancomycin, linezolid, clindamycin, and gentamicin failed to achieve synergy in checkerboard experiments. Levofloxacin and fluoxetine were the only combination that demonstrated synergy against a Gram-positive pathogen in both checkerboard and time-killing experiments (1/6 isolates, 16.7%). Against Gram-negative organisms, the most promising combination was fluoxetine and polymyxin B, which achieved synergistic killing in both checkerboard experiments and time-killing experiments in 12/15 isolates (80%). In comparison, fosfomycin and meropenem achieved synergy in both experiments against 6/15 (40%) and 3/15 (20%) Gram-negative isolates, respectively. Conclusions: The combination of fluoxetine and polymyxin B may be a potential strategy for combatting difficult-to-treat Gram-negative pathogens.

Risk factors for Pseudomonas aeruginosa VIM colonization or infection in the ICU: Case-control study

BACKGROUND

Carbapenem-resistant strains of Pseudomonas aeruginosa (CRPA) have become a major health care concern in many countries, against which anti-infective strategies are limited and which require adequate infection control interventions. Knowing the different modes of transmission of CRPA in intensive care units (ICUs) would be helpful to adapt the means of prevention.

METHODS

The aim of this retrospective case-control study was conducted between January 1, 2017 and February 28, 2022 to identify the risk factors for the acquisition of CRPA in ICUs.

RESULTS

During the study period, 147 patients were included (49 cases and 98 controls). Among the 49 patients, 31 (63%) acquired CRPA in clusters and 18 (37%) sporadically. A univariate analysis showed that 4 variables were associated with CRPA acquisition, including (1) prior antibiotic prescriptions, (2) admission to rooms 203 and 207, (3) severity of illness at admission, and (4) use of mechanical ventilation. Multivariate analysis identified 3 factors of CRPA acquisition, including admission to room 203 (odds ratio [OR] = 29.5 [3.52-247.09]), previous antibiotic therapy (OR = 3.44 [1.02-11.76]), and severity of condition at admission (OR = 1.02 [1-1.04]).

CONCLUSIONS

Our study suggests the role of a contaminated environment in the acquisition of CRPA in the ICU, along with antibiotic use.

The Repurposing of FDA-Approved Drugs as FtsZ Inhibitors against Mycobacterium tuberculosis: An In Silico and In Vitro Study

Mycobacterium tuberculosis (Mtb), the causative pathogen of tuberculosis, remains one of the leading causes of death from a single infectious agent. Furthermore, the growing evolution to multi-drug-resistant (MDR) strains requires de novo identification of drug targets for evaluating candidates or repurposing drugs. Hence, targeting FtsZ, an essential cell division protein, is a promising target.

METHODS

Using an in silico pharmacological repositioning strategy, four FDA-based drugs that bind to the catalytic site FtsZ were selected. The Alamar Blue colorimetric assay was used to assess antimicrobial activity and the effect of drugs on Mtb growth through growth curves. Bacterial load was determined with an in vitro infection model using colony-forming units (CFU)/mL, and cytotoxicity on human monocyte-derived macrophages (MDMhs) was assessed by flow cytometry.

RESULTS

Paroxetine and nebivolol exhibited antimycobacterial activity against both reference TB and MDR strains at a concentration of 25 µg/mL. Furthermore, both paroxetine and nebivolol demonstrated a significant reduction (p < 0.05) in viable bacteria compared to the untreated group in the in vitro infection model.

CONCLUSIONS

Collectively, our findings demonstrate that the use of paroxetine and nebivolol is a promising strategy to help in the control of tuberculosis infection.

Improving the treatment of bacterial infections caused by multidrug-resistant bacteria through drug repositioning

Drug repurposing (repositioning) is a dynamically-developing area in the search for effective therapy of infectious diseases. Repositioning existing drugs with a well-known pharmacological and toxicological profile is an attractive method for quickly discovering new therapeutic indications. The off-label use of drugs for infectious diseases requires much less capital and time, and can hasten progress in the development of new antimicrobial drugs, including antibiotics. The use of drug repositioning in searching for new therapeutic options has brought promising results for many viral infectious diseases, such as Ebola, ZIKA, Dengue, and HCV. This review describes the most favorable results for repositioned drugs for the treatment of bacterial infections. It comprises publications from various databases including PubMed and Web of Science published from 2015 to 2023. The following search keywords/strings were used: drug repositioning and/or repurposing and/or antibacterial activity and/or infectious diseases. Treatment options for infections caused by multidrug-resistant bacteria were taken into account, including methicillin-resistant staphylococci, multidrug-resistant Mycobacterium tuberculosis, or carbapenem-resistant bacteria from the Enterobacteriaceae family. It analyses the safety profiles of the included drugs and their synergistic combinations with antibiotics and discusses the potential of antibacterial drugs with antiparasitic, anticancer, antipsychotic effects, and those used in metabolic diseases. Drug repositioning may be an effective response to public health threats related to the spread of multidrug-resistant bacterial strains and the growing antibiotic resistance of microorganisms.

Hypidone hydrochloride (YL-0919) protects mice from meningitis via Sigma1R-STAT1-NLRP3-GSDMD pathway

BACKGROUND

A growing number of studies have found that antidepressants have anti-inflammatory effects while protecting nerves. Hypidone hydrochloride (YL-0919) is a novel highly selective 5-HT reuptake blocker. Our previous studies have demonstrated that YL-0919 exerts notable antidepressant- and anxiolytic-like as well as procognitive effects. However, whether YL-0919 can be used to treat inflammatory and infectious diseases remain unknown. In this study, we aimed to verify the anti-inflammatory effect of YL-0919 on bacterial meningitis and further explore the potential molecular mechanisms.

METHODS

We performed the experiments on pneumococcal meningitis mice in vivo and S. pneumoniae infected macrophages/microglia in vitro, with or without YL-0919 treatment. Cognitive function was evaluated by open-field task, Morris water maze test, and novel object recognition test. Histopathological staining and immunofluorescence staining were used to detect the pathological damage of meningitis and NLRP3 inflammasome activation in microglia/macrophages. The expression of the STAT1/NLRP3/GSDMD signal pathway was measured by western blots. Proinflammatory cytokines associated with pyroptosis were detected by ELISA.

RESULTS

YL-0919 protected mice from fatal pneumococcal meningitis, characterized by attenuated cytokine storms, decreased bacterial loads, improved neuroethology, and reduced mortality. NLRP3 plays a key role in the regulation of inflammation. When the underlying mechanisms were investigated, we found that YL-0919 inhibited the activation of NLRP3 via STAT1, and thus inhibited macrophages/microglia pyroptosis, resulting in downregulation of proinflammatory cytokines. In addition, Sigma1R was identified as a pivotal receptor that can be engaged by YL-0919 to inhibit NLRP3 activation and pyroptosis pathway in microglia/macrophages.

CONCLUSIONS

These results provide new insights into the mechanisms of inflammation regulation mediated by the antidepressant YL-0919. Moreover, targeting the STAT1/NLRP3 pyroptosis pathway is a promising strategy for the treatment of infectious diseases like bacterial meningitis.

AADB: A Manually Collected Database for Combinations of Antibiotics With Adjuvants

Antimicrobial resistance is a global public health concern. The lack of innovations in antibiotic development has led to renewed interest in antibiotic adjuvants. However, there is no database to collect antibiotic adjuvants. Herein, we build a comprehensive database named Antibiotic Adjuvant DataBase (AADB) by manually collecting relevant literature. Specifically, AADB includes 3,035 combinations of antibiotics with adjuvants, covering 83 antibiotics, 226 adjuvants, and 325 bacterial strains. AADB provides user-friendly interfaces for searching and downloading. Users can easily obtain these datasets for further analysis. In addition, we also collected related datasets (e.g., chemogenomic and metabolomic data) and proposed a computational strategy to dissect these datasets. As a test case, we identified 10 candidates for minocycline, and 6 of 10 candidates are the known adjuvants that synergize with minocycline to inhibit the growth of E. coli BW25113. We hope that AADB can help users to identify effective antibiotic adjuvants. AADB is freely available at http://www.acdb.plus/AADB.

Antibacterial activity of paroxetine against Staphylococcus aureus and possible mechanisms of action

Aim: To evaluate the antibacterial activity of paroxetine alone and associated with oxacillin against isolates of methicillin-sensitive and -resistant Staphylococcus aureus. Materials & methods: The broth microdilution and checkerboard techniques were used, with investigation of possible mechanisms of action through flow cytometry, fluorescence microscopy and molecular docking, in addition to scanning electron microscopy for morphological analysis. Results: Paroxetine showed a MIC of 64 μg/ml and bactericidal activity, mostly additive interactions in combination with oxacillin, evidence of action on genetic material and membrane, morphological changes in microbial cells and influence on virulence factors. Conclusion: Paroxetine has antibacterial potential from the perspective of drug repositioning.

Role of the Intestinal Microbiota in the Genesis of Major Depression and the Response to Antidepressant Drug Therapy: A Narrative Review

A major depressive disorder is a serious mental illness characterized by a pervasive low mood that negatively concerns personal life, work life, or education, affecting millions of people worldwide. To date, due to the complexity of the disease, the most common and effective treatments consist of a multi-therapy approach, including psychological, social, and pharmacological support with antidepressant drugs. In general, antidepressants are effective in correcting chemical imbalances of neurotransmitters in the brain, but recent evidence has underlined the pivotal role of gut microbiota (GM) also in the regulation of their pharmacokinetics/pharmacodynamics, through indirect or direct mechanisms. The study of these complex interactions between GM and drugs is currently under the spotlight, and it has been recently named "pharmacomicrobiomics". Hence, the purpose of this review is to summarize the contribution of GM and its metabolites in depression, as well as their role in the metabolism and activity of antidepressant drugs, in order to pave the way for the personalized administration of antidepressant therapies.

TCA and SSRI Antidepressants Exert Selection Pressure for Efflux-Dependent Antibiotic Resistance Mechanisms in Escherichia coli

Microbial diversity is reduced in the gut microbiota of animals and humans treated with selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). The mechanisms driving the changes in microbial composition, while largely unknown, is critical to understand considering that the gut microbiota plays important roles in drug metabolism and brain function. Using Escherichia coli, we show that the SSRI fluoxetine and the TCA amitriptyline exert strong selection pressure for enhanced efflux activity of the AcrAB-TolC pump, a member of the resistance-nodulation-cell division (RND) superfamily of transporters. Sequencing spontaneous fluoxetine- and amitriptyline-resistant mutants revealed mutations in marR and lon, negative regulators of AcrAB-TolC expression. In line with the broad specificity of AcrAB-TolC pumps these mutants conferred resistance to several classes of antibiotics. We show that the converse also occurs, as spontaneous chloramphenicol-resistant mutants displayed cross-resistance to SSRIs and TCAs. Chemical-genomic screens identified deletions in marR and lon, confirming the results observed for the spontaneous resistant mutants. In addition, deletions in 35 genes with no known role in drug resistance were identified that conferred cross-resistance to antibiotics and several displayed enhanced efflux activities. These results indicate that combinations of specific antidepressants and antibiotics may have important effects when both are used simultaneously or successively as they can impose selection for common mechanisms of resistance. Our work suggests that selection for enhanced efflux activities is an important factor to consider in understanding the microbial diversity changes associated with antidepressant treatments. IMPORTANCE Antidepressants are prescribed broadly for psychiatric conditions to alter neuronal levels of synaptic neurotransmitters such as serotonin and norepinephrine. Two categories of antidepressants are selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs); both are among the most prescribed drugs in the United States. While it is well-established that antidepressants inhibit reuptake of neurotransmitters there is evidence that they also impact microbial diversity in the gastrointestinal tract. However, the mechanisms and therefore biological and clinical effects remain obscure. We demonstrate antidepressants may influence microbial diversity through strong selection for mutant bacteria with increased AcrAB-TolC activity, an efflux pump that removes antibiotics from cells. Furthermore, we identify a new group of genes that contribute to cross-resistance between antidepressants and antibiotics, several act by regulating efflux activity, underscoring overlapping mechanisms. Overall, this work provides new insights into bacterial responses to antidepressants important for understanding antidepressant treatment effects.

Anti-infective properties of proton pump inhibitors: perspectives

Infectious diseases are among the main causes of morbidity and mortality today. In facing this crisis, the development of new drug options and combat strategies is necessary. In this sense, drug repositioning or drug redirection has emerged for the faster identification of effective drugs. In this “Commentary,” the anti-infective properties of the class of proton pump inhibitors (PPIs) are emphasized. Studies report activities against bacterial, fungal, parasitic, and viral agents. In addition, we have provided in a table a summary of the specific characteristics of PPIs and some of their anti-infective activities.