Changing Priorities in Vaccinology: Antibiotic Resistance Moving to the Top

Chemical composition, antibacterial potential, and toxicity of the extracts from the stem bark of Hancornia speciosa Gomes (Apocynaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa is a medicinal plant popularly used to treat different medical issues, including infectious diseases. Exploring the therapeutic potentialities of the extracts from medicinal plants combined with conventional antibiotic drugs is a promising horizon, especially considering the rising microbial resistance.

AIM OF THE STUDY

This study aimed to characterize the chemical composition of the ethereal (EEHS) and methanolic (MEHS) extracts of the stem bark of H. speciosa, and also evaluate their antibacterial and drug-modifying activity, and toxicity.

MATERIALS AND METHODS

The extracts were characterized by gas chromatography coupled to mass spectrometry (GC-MS). Additionally, total phenol and flavonoid contents were determined. The antibacterial and antibiotic-modifying activity was evaluated against strains of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa using the serial microdilution method, obtaining the minimum inhibitory concentration (MIC). The toxicity assay was carried out using the Drosophila melanogaster model.

RESULTS

Thirty compounds were identified in the extracts of the stem bark of H. speciosa, with triterpenoids being predominant in both extracts. Additionally, fatty alcohols, carbohydrates, fatty acids, phenolic acids, and phytosterols were identified in both extracts. EEHS and MEHS extracts had considerable phenol contents (346.4 and 340.0 mg GAE/g, respectively). Flavonoids were detected in a lower proportion (7.6 and 6.9 mg QE/g, respectively). H. speciosa extracts did not display intrinsic antibacterial activity against the bacterial strains evaluated, however, they were capable of modifying the activity of gentamicin, erythromycin, and norfloxacin. EEHS increased the efficacy of norfloxacin against E. coli and S. aureus, reducing MIC values by 50%. MEHS potentiated the action of gentamicin against all bacterial strains, especially against E. coli. The extracts did not display toxicity at clinically relevant concentrations against D. melanogaster.

CONCLUSION

The stem bark of H. speciosa was considered a rich source of bioactive compounds. Our findings evidenced the therapeutic potential of H. speciosa extracts for the development of new pharmaceutical therapeutics against bacteria. Although the extracts did not exhibit intrinsic antibacterial activity, they enhanced the efficacy of commercial antibiotic drugs and were non-toxic at clinically relevant concentrations. Future studies are needed to elucidate the mechanisms of action of these extracts, ensuring their safety and efficacy.

Decoding antimicrobial resistance: unraveling molecular mechanisms and targeted strategies

Antimicrobial resistance poses a significant global health threat, necessitating innovative approaches for combatting it. This review explores various mechanisms of antimicrobial resistance observed in various strains of bacteria. We examine various strategies, including antimicrobial peptides (AMPs), novel antimicrobial materials, drug delivery systems, vaccines, antibody therapies, and non-traditional antibiotic treatments. Through a comprehensive literature review, the efficacy and challenges of these strategies are evaluated. Findings reveal the potential of AMPs in combating resistance due to their unique mechanisms and lower propensity for resistance development. Additionally, novel drug delivery systems, such as nanoparticles, show promise in enhancing antibiotic efficacy and overcoming resistance mechanisms. Vaccines and antibody therapies offer preventive measures, although challenges exist in their development. Non-traditional antibiotic treatments, including CRISPR-Cas systems, present alternative approaches to combat resistance. Overall, this review underscores the importance of multifaceted strategies and coordinated global efforts to address antimicrobial resistance effectively.

Highly Efficient Photodynamic Hydrogel with AIE-Active Photosensitizers toward Methicillin-Resistant Staphylococcus aureus Ultrafast Imaging and Killing

Methicillin-resistant Staphylococcus aureus (MRSA) causes great health hazards to society because most antibiotics are ineffective. Photodynamic treatment (PDT) has been proposed to combat MRSA due to the advantage of imaging-guided no-drug resistance therapy. However, the traditional photosensitizers for PDT are limited by aggregation-caused quenching for imaging and low photodynamic antibacterial efficiency. In this work, we synthesize a new aggregation-induced emission (AIE) photosensitizer (APNO), which can ultrafast distinguish between Gram-positive and Gram-negative bacteria within 3 s by AIE-active photosensitizer imaging. Meanwhile, APNO can generate antibacterial reactive oxygen species under light irradiation, which holds potential for antibacterial PDT. Then, APNO is loaded by PHEAA hydrogel to obtain a highly efficient photodynamic hydrogel (APNO@gel). In vitro results show complete inhibition of MRSA by APNO@gel under lower-power light irradiation. Transcriptome analysis is performed to investigate antibacterial mechanism of APNO@gel. Most importantly, APNO@gel also exhibits significant inhibition and killing ability of MRSA in the MRSA wound infection model, which will further promote rapid wound healing. Therefore, the photodynamic hydrogel provides a promising strategy toward MRSA ultrafast imaging and killing.

2,3-Dichloronaphthoquinone derivatives: Synthesis, antimicrobial activity, molecular modelling and ADMET studies

In the present study, an intermediate namely 2-(3-bromopropylamino)-3-chloronaphthalene-1,4-dione was initially synthesized via the nucleophilic addition-elimination reaction between 2,3-dichloro-1,4-naphthoquinone and 3-bromo-1-aminopropane. Then a coupling reaction between the intermediate and piperazine derivatives yielded a number of 1,4-naphthoquinone derivatives. Spectroscopic analysis successfully characterized the products that were obtained in good yields. In vitro antibacterial properties of the compounds were examined against different bacterial strains. In vitro antibacterial properties of the compounds were examined against the bacterial strains S. Aureus, E. Faecalis, E. Coli and P. Aeruginosa. While compound 9 was found to be effective against all bacterial strains used, compound 12 was active against three strains and compounds 10 and 11 were effective against the two. None of the compounds are effective against C. albicans strain. In silico molecular docking studies revealed that all compounds had docking scores comparable to the antibacterial drugs ciprofloxacin and gentamicin and might be considered as DNA gyrase B inhibitors. Molecular dynamics simulations were also conducted for a better understanding of the stability and the selected docked complexes. Additionally, the drug similarity of the synthesized compounds and ADMET characteristics were examined in conjunction with the antibiotic ciprofloxacin, and drug potentials were then evaluated. Compatible predictions were found with the drug similarity and ADMET parameters.

Invited review: "Probiotic" approaches to improving dairy production: Reassessing "magic foo-foo dust"

The gastrointestinal microbial consortium in dairy cattle is critical to determining the energetic status of the dairy cow from birth through her final lactation. The ruminant's microbial community can degrade a wide variety of feedstuffs, which can affect growth, as well as production rate and efficiency on the farm, but can also affect food safety, animal health, and environmental impacts of dairy production. Gut microbial diversity and density are powerful tools that can be harnessed to benefit both producers and consumers. The incentives in the United States to develop Alternatives to Antibiotics for use in food-animal production have been largely driven by the Veterinary Feed Directive and have led to an increased use of probiotic approaches to alter the gastrointestinal microbial community composition, resulting in improved heifer growth, milk production and efficiency, and animal health. However, the efficacy of direct-fed microbials or probiotics in dairy cattle has been highly variable due to specific microbial ecological factors within the host gut and its native microflora. Interactions (both synergistic and antagonistic) between the microbial ecosystem and the host animal physiology (including epithelial cells, immune system, hormones, enzyme activities, and epigenetics) are critical to understanding why some probiotics work but others do not. Increasing availability of next-generation sequencing approaches provides novel insights into how probiotic approaches change the microbial community composition in the gut that can potentially affect animal health (e.g., diarrhea or scours, gut integrity, foodborne pathogens), as well as animal performance (e.g., growth, reproduction, productivity) and fermentation parameters (e.g., pH, short-chain fatty acids, methane production, and microbial profiles) of cattle. However, it remains clear that all direct-fed microbials are not created equal and their efficacy remains highly variable and dependent on stage of production and farm environment. Collectively, data have demonstrated that probiotic effects are not limited to the simple mechanisms that have been traditionally hypothesized, but instead are part of a complex cascade of microbial ecological and host animal physiological effects that ultimately impact dairy production and profitability.

Comparative investigation of derivatives of (E)-N-((E)-3-phenylallylidene)aniline: Synthesis, structural characterization, biological evaluation, density functional theory analysis, and in silico molecular docking

Bacterial resistance to antibiotics poses a significant global challenge for the public sector. Globally, researchers are actively investigating solutions to tackle the issue of bacterial resistance to antibiotics, with Schiff bases standing out as promising contenders in the fight against antimicrobial resistance. This study focused on synthesizing a series of Schiff bases (CA1-CA10) by reacting cinnamaldehyde with various aniline derivatives. Various analytical techniques, such as NMR, FTIR, UV-Vis, elemental analysis, and mass spectrometry, were employed to elucidate the structures of the synthesized compounds. Furthermore, crystal structure of CA8 was obtained using single crystal X-ray spectroscopy. The compounds were subjected to in vitro testing to assess their antibacterial and antifungal properties against eleven bacterial strains and four fungal strains. The results revealed diverse activity levels against the pathogens at varying concentrations, with notable potency observed in compounds CA3, CA4, CA9, and CA10, as indicated by their minimum inhibitory concentrations (MIC) values. The observed activity of the compounds seemed to be influenced by the specific substituents attached to their molecular structure. By conducting computational and molecular docking studies, the electronic properties of the compounds were investigated, further substantiating their potential as effective antimicrobial agents.

Combating antimicrobial resistance: the silent war

Once hailed as miraculous solutions, antibiotics no longer hold that status. The excessive use of antibiotics across human healthcare, agriculture, and animal husbandry has given rise to a broad array of multidrug-resistant (MDR) pathogens, posing formidable treatment challenges. Antimicrobial resistance (AMR) has evolved into a pressing global health crisis, linked to elevated mortality rates in the modern medical era. Additionally, the absence of effective antibiotics introduces substantial risks to medical and surgical procedures. The dwindling interest of pharmaceutical industries in developing new antibiotics against MDR pathogens has aggravated the scarcity issue, resulting in an exceedingly limited pipeline of new antibiotics. Given these circumstances, the imperative to devise novel strategies to combat perilous MDR pathogens has become paramount. Contemporary research has unveiled several promising avenues for addressing this challenge. The article provides a comprehensive overview of these innovative therapeutic approaches, highlighting their mechanisms of action, benefits, and drawbacks.

Promising bioprocesses for the efficient removal of antibiotics and antibiotic-resistance genes from urban and hospital wastewaters: Potentialities of aerobic granular systems

The use, overuse, and improper use of antibiotics have resulted in higher levels of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs), which have profoundly disturbed the equilibrium of the environment. Furthermore, once antibiotic agents are excreted in urine and feces, these substances often can reach wastewater treatment plants (WWTPs), in which improper treatments have been highlighted as the main reason for stronger dissemination of antibiotics, ARB, and ARGs to the receiving bodies. Hence, achieving better antibiotic removal capacities in WWTPs is proposed as an adequate approach to limit the spread of antibiotics, ARB, and ARGs into the environment. In this review, we highlight hospital wastewater (WW) as a critical hotspot for the dissemination of antibiotic resistance due to its high level of antibiotics and pathogens. Hence, monitoring the composition and structure of the bacterial communities related to hospital WW is a key factor in controlling the spread of ARGs. In addition, we discuss the advantages and drawbacks of the current biological WW treatments regarding the antibiotic-resistance phenomenon. Widely used conventional activated sludge technology has proved to be ineffective in mitigating the dissemination of ARB and ARGs to the environment. However, aerobic granular sludge (AGS) technology is a promising technology-with broad adaptability and excellent performance-that could successfully reduce antibiotics, ARB, and ARGs in the generated effluents. We also outline the main operational parameters involved in mitigating antibiotics, ARB, and ARGs in WWTPs. In this regard, WW operation under long hydraulic and solid retention times allows better removal of antibiotics, ARB, and ARGs independently of the WW technology employed. Finally, we address the current knowledge of the adsorption and degradation of antibiotics and their importance in removing ARB and ARGs. Notably, AGS can enhance the removal of antibiotics, ARB, and ARGs due to the complex microbial metabolism within the granular biomass.

An insights into emerging trends to control the threats of antimicrobial resistance (AMR): an address to public health risks

Antimicrobial agents are used to treat microbial ailments, but increased use of antibiotics and exposure to infections in healthcare facilities and hospitals as well as the excessive and inappropriate use of antibiotics at the society level lead to the emergence of multidrug-resistant (MDR) bacteria. Antimicrobial resistance (AMR) is considered a public health concern and has rendered the treatment of different infections more challenging. The bacterial strains develop resistance against antimicrobial agents by limiting intracellular drug accumulation (increasing efflux or decreasing influx of antibiotics), modification and inactivation of drugs and its targets, enzymatic inhibition, and biofilm formation. However, the driving factors of AMR include the sociocultural and economic circumstances of a country, the use of falsified and substandard medicines, the use of antibiotics in farm animals, and food processing technologies. These factors make AMR one of the major menaces faced by mankind. In order to promote reciprocal learning, this article summarizes the current AMR situation in Pakistan and how it interacts with the health issues related to the COVID-19 pandemic. The COVID-19 pandemic aids in illuminating the possible long-term impacts of AMR, which are less immediate but not less severe since their measures and effects are equivalent. Impact on other sectors, including the health industry, the economy, and trade are also discussed. We conclude by summarizing the several approaches that could be used to address this issue.

BPI23-Fcγ alleviates lethal multi-drug-resistant Acinetobacter baumannii infection by enhancing bactericidal activity and orchestrating neutrophil function

Antibiotic resistance has become a major threat, contributing significantly to morbidity and mortality globally. Administering non-antibiotic therapy, such as antimicrobial peptides, is one potential strategy for effective treatment of multi-drug-resistant Gram-negative bacterial infections. Bactericidal/permeability-increasing protein (BPI) derived from neutrophils has bactericidal and endotoxin-neutralizing activity. However, the protective roles and mechanisms of BPI in multi-drug-resistant bacterial infections have not been fully elucidated. In this study, a chimeric BPI23-Fcγ recombined protein comprising the functional N terminus of BPI and Fcγ was constructed and expressed by adenovirus vector 5 (Ad5). Ad5-BPI23-Fcγ or recombinant BPI23-Fcγ protein significantly improved the survival of mice with pneumonia induced by a minimal lethal dose of multi-drug-resistant Acinetobacter baumannii or Klebsiella pneumoniae by ameliorating lung pathology and reducing pro-inflammatory cytokines. Transfection with Ad5-BPI23-Fcγ significantly decreased the bacterial load and endotoxaemia, which was associated with enhanced bactericidal ability and elevated the phagocytic activity of neutrophils in vitro and in vivo. In addition, Ad5-BPI23-Fcγ transfection significantly increased the recruitment of neutrophils to lung, increased the proportion and number of neutrophils in peripheral blood, and promoted the maturation of bone marrow (BM) neutrophils after drug-resistant A. baumannii infection. BPI23-Fcγ and neutrophils synergistically enhanced bactericidal activity and decreased pro-inflammatory cytokines. These results demonstrated that the chimeric BPI23-Fcγ protein protected mice from pneumonia induced by multi-drug-resistant A. baumannii infection by direct bactericidal effects and promotion of neutrophil recruitment, phagocytosis and maturation. Chimeric BPI23-Fcγ may be a promising candidate as a non-antibiotic biological agent for multi-drug-resistant A. baumannii infection.

Antimicrobial Effects of Plant-Based Supplements on Gut Microbial Diversity in Small Ruminants

Every year in the United States, approximately 48 million people are affected by bacterial illnesses that are transmitted through food, leading to 3000 fatalities. These illnesses typically stem from food animals and their by-products, which may harbor dangerous pathogens like Salmonella enterica, Listeria monocytogenes, enterohemorrhagic Escherichia coli O157:H7, and Campylobacter jejuni. Factors that contribute to contamination include manure used as a soil amendment, exposure to polluted irrigation water, and contact with animals. To improve food safety, researchers are studying pre-slaughter intervention methods to eliminate bacterial contamination in live animals. While small ruminants are vital to global agriculture and income generation for small farms, traditional feeding practices involve supplements and antibiotics to boost performance, which contributes to antibiotic resistance. Hence, researchers are looking for friendly bacterial strains that enhance both animal and human health without impacting livestock productivity. The global trend is to minimize the use of antibiotics as feed supplements, with many countries prohibiting or limiting their use. The aim of this review is to provide a comprehensive insight on the antioxidant capabilities, therapeutic attributes, and applications of bioactive compounds derived from sweet potato tops (SPTs), rice bran (RB) and radish tops (RTs). This overview provides an insight on plant parts that are abundant in antioxidant and prebiotic effects and could be used as value-added products in animal feed and pharmaceutical applications. This review was based on previous findings that supplementation of basal diets with natural supplements represents a multifaceted intervention that will become highly important over time. By remarkably reducing the burden of foodborne pathogens, they apply to multiple species, are cheap, do not require withdrawal periods, and can be applied at any time in food animal production.

Evaluation of parents' attitudes and practices related to antibiotic use for their children in Kosovo: a cross-sectional survey

BACKGROUND

Self-medication and lack of patient adherence contribute to antibiotic misuse. This article describes parents' attitudes and practices regarding use of antibiotics by their children in Kosovo.

METHODS

A cross-sectional survey was conducted during data collection. We surveyed a total of 453 parents of children aged 0-15 years, who had experiences with using antibiotics for their children. Correlation tests and regression analysis were used to explore the relationship between variables.

RESULTS

Our findings showed that 42.2% of parents strongly agreed or agreed with the use of antibiotics as a means to cure a cold or flu in their child more quickly. In addition, 29.8% were not aware of antibiotic side effects. Non-compliance with antibiotic treatment was 35.8%, and 28.9% of surveyed parents suggested that they had pressured their pediatricians to prescribe antibiotics for their children. A total of 10.15% of parents had no information on antibiotic resistance, and 34.38% of parents responded that they did not believe that self-medication with antibiotics could lead to resistance. Regression analysis results indicated that gender and age group have a significant influence on the parents' decision that an antibiotic should be used in children with high fever (p < 0.001).

CONCLUSIONS

Our findings suggest that antibiotic management by parents in Kosovo is not satisfactory, and more attention should be given to their knowledge of the side effects of antibiotics, bacterial resistance and reduction in the self-medication. Health education, adequate measures and interventions are needed to overcome this situation and ensure rational use of antibiotics in Kosovo.

Deciphering the Role of WWTPs in Cold Environments as Hotspots for the Dissemination of Antibiotic Resistance Genes

Cold environments are the most widespread extreme habitats in the world. However, the role of wastewater treatment plants (WWTPs) in the cryosphere as hotspots in antibiotic resistance dissemination has not been well established. Hence, a snapshot of the resistomes of WWTPs in cold environments, below 5 °C, was provided to elucidate their role in disseminating antibiotic resistance genes (ARGs) to the receiving waterbodies. The resistomes of two natural environments from the cold biosphere were also determined. Quantitative PCR analysis of the aadA, aadB, ampC, blaSHV, blaTEM, dfrA1, ermB, fosA, mecA, qnrS, and tetA(A) genes indicated strong prevalences of these genetic determinants in the selected environments, except for the mecA gene, which was not found in any of the samples. Notably, high abundances of the aadA, ermB, and tetA(A) genes were found in the influents and activated sludge, highlighting that WWTPs of the cryosphere are critical hotspots for disseminating ARGs, potentially worsening the resistance of bacteria to some of the most commonly prescribed antibiotics. Besides, the samples from non-disturbed cold environments had large quantities of ARGs, although their ARG profiles were highly dissimilar. Hence, the high prevalences of ARGs lend support to the fact that antibiotic resistance is a common issue worldwide, including environmentally fragile cold ecosystems.

Crisis averted: a world united against the menace of multiple drug-resistant superbugs -pioneering anti-AMR vaccines, RNA interference, nanomedicine, CRISPR-based antimicrobials, bacteriophage therapies, and clinical artificial intelligence strategies to safeguard global antimicrobial arsenal

The efficacy of antibiotics and other antimicrobial agents in combating bacterial infections faces a grave peril in the form of antimicrobial resistance (AMR), an exceedingly pressing global health issue. The emergence and dissemination of drug-resistant bacteria can be attributed to the rampant overuse and misuse of antibiotics, leading to dire consequences such as organ failure and sepsis. Beyond the realm of individual health, the pervasive specter of AMR casts its ominous shadow upon the economy and society at large, resulting in protracted hospital stays, elevated medical expenditures, and diminished productivity, with particularly dire consequences for vulnerable populations. It is abundantly clear that addressing this ominous threat necessitates a concerted international endeavor encompassing the optimization of antibiotic deployment, the pursuit of novel antimicrobial compounds and therapeutic strategies, the enhancement of surveillance and monitoring of resistant bacterial strains, and the assurance of universal access to efficacious treatments. In the ongoing struggle against this encroaching menace, phage-based therapies, strategically tailored to combat AMR, offer a formidable line of defense. Furthermore, an alluring pathway forward for the development of vaccines lies in the utilization of virus-like particles (VLPs), which have demonstrated their remarkable capacity to elicit a robust immune response against bacterial infections. VLP-based vaccinations, characterized by their absence of genetic material and non-infectious nature, present a markedly safer and more stable alternative to conventional immunization protocols. Encouragingly, preclinical investigations have yielded promising results in the development of VLP vaccines targeting pivotal bacteria implicated in the AMR crisis, including Salmonella, Escherichia coli, and Clostridium difficile. Notwithstanding the undeniable potential of VLP vaccines, formidable challenges persist, including the identification of suitable bacterial markers for vaccination and the formidable prospect of bacterial pathogens evolving mechanisms to thwart the immune response. Nonetheless, the prospect of VLP-based vaccines holds great promise in the relentless fight against AMR, underscoring the need for sustained research and development endeavors. In the quest to marshal more potent defenses against AMR and to pave the way for visionary innovations, cutting-edge techniques that incorporate RNA interference, nanomedicine, and the integration of artificial intelligence are currently under rigorous scrutiny.

Biosynthesis and characterization of silver nanoparticles from Punica granatum (pomegranate) peel waste and its application to inhibit foodborne pathogens

Polyphenolics have been predicted to effectively develop antimicrobial agents for the food industry as food additives and promote human health. This study aims to synthesize pomegranate peel extract (PPE) with silver nanoparticles (AgNPs) against eight foodborne pathogens. Multispectroscopic analysis of UV-vis spectroscopy, Zeta potential, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis were used to characterize the interaction between PPE and AgNPs. Eight foodborne pathogenic strains (six bacterial and two fungal strains) Bacillus subtilis ATCC 6633, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 8379, Klebsiella pneumoniae ATCC 00607, Salmonella typhi DSM 17058, Shigella sonnei DSM 5570, Aspergillus flavus ATCC 9643, and Rhizopus oryzae ATCC 96382 were used to test the inhibitory potential of PPW-AgNPs. The reaction colour of PPE-AgNPs from yellow to brown indicated that the nanoparticles were successfully formed. The UV absorption of PPE-AgNPs was detected at 440 nm of 0.9 SPR. SEM image of PPE-AgNPs exhibited spherical shapes with a zeta potential of - 20.1 mV. PPE-AgNPs showed high antimicrobial activity against all tested strains. The highest inhibition activity of PPE-AgNPs was recorded for the B. subtilis strain followed by K. pneumonia, while the highest resistance was noticed for R. oryzae. The components of pomegranate peel were analyzed using gas chromatography-mass spectrometry (GC-MS). The major constituents of pomegranate peel is phenol (51.1%), followed by Isocitronellol (19.41%) and 1-Propanol, 2-(2-hydroxypropyl)- (16.05%). PPE is key in the simple, eco-friendly green synthesis of extracellular stable AgNPs as an alternative source for harmful chemical disinfectants.

A review of current antibiotic resistance and promising antibiotics with novel modes of action to combat antibiotic resistance

The emergence and transmission of antibiotic resistance is a global public health crisis with significant burden on healthcare systems, resulting in high mortality and economic costs. In 2019, almost five million deaths were associated with drug-resistant infections, and if left unchecked, the global economy could lose $100 trillion by 2050. To effectively combat this crisis, it is essential for all countries to understand the current situation of antibiotic resistance. In this review, we examine the current driving factors leading to the crisis, impact of critical superbugs in three regions, and identify novel mechanisms of antibiotic resistance. It is crucial to monitor the phenotypic characteristics of drug-resistant pathogens and describe the mechanisms involved in preventing the emergence of cross-resistance to novel antimicrobials. Additionally, maintaining an active pipeline of new antibiotics is essential for fighting against diverse antibiotic-resistant pathogens. Developing antibacterial agents with novel mechanisms of action is a promising way to combat increasing antibiotic-resistant pathogens.

Reverse vaccinology & immunoinformatics approach to design a multiepitope vaccine (CV3Ag-antiMRSA) against methicillin resistant Staphylococcus aureus (MRSA) - a pathogen affecting both human and animal health

Infections caused by drug resistant bacteria is a silent detrimental pandemic affecting the global health care profoundly. Methicillin resistant Staphylococcus aureus (MRSA) is a pathogen that causes serious infections in different settings (community, hospital & veterinary) whose treatment remains highly challenging due to its powerful characteristics (antibiotic resistance strategies, virulence factors). In this study, we used reverse vaccinology (RV) approach and designed an immunogenic multi epitope vaccine (CV3Ag-antiMRSA) targeting three potential antigen candidates viz., mecA encoding transpeptidase (PBP2a) protein responsible for conferring methicillin resistance and two virulence determinants - hlgA encoding gamma-hemolysin component A (a pore forming toxin) and isdB encoding iron regulated surface determinant B (heme transport component that allows S. aureus to scavenge iron from host hemoglobin and myoglobin). We employed an array of immunoinformatic tools/server to identify and use immunogenic epitopes (B cell and MHC class) to develop the chimeric subunit vaccine V4 (CV3Ag-antiMRSA) with immune modulating adjuvant and linkers. Based on different parameters, the vaccine construct V4 (CV3Ag-antiMRSA) was determined to be suitable vaccine (antigenic and non-allergen). Molecular docking and simulation of CV3Ag-antiMRSA with Toll Like Receptor (TLR2) predicted its immuno-stimulating potential. Finally, in silico cloning of CV3Ag-antiMRSA construct into pet28a and pet30 vector displayed its feasibility for the heterologous expression in the E. coli expression system. This vaccine candidate (CV3Ag-antiMRSA) designed based on the MRSA genomes obtained from both animal and human hosts can be experimentally validated and thereby contribute to vaccine development to impart protection to both animal and human health.Communicated by Ramaswamy H. Sarma.

Call for next-generation drugs that remove the uptake barrier to combat antibiotic resistance

Existing antibacterial agents can be categorized into two generations, but bacterial insensitivity towards both of these generations poses a serious public health challenge worldwide. Thus, novel approaches and/or novel antibacterials are urgently needed to maintain a concentration of antibacterials that is lethal to bacteria that are resistant to existing antibiotic treatments. Metabolite(s)-based adjuvants that promote antibiotic uptake and enhance antibiotic efficacy are an effective strategy that is unlikely to develop resistance. Thus, we propose a metabolite(s)-based approach, in which metabolites and antibacterials are combined, as a promising strategy for the development of next-generation agents to combat a variety of antibiotic-resistant pathogens.

Structure-based drug discovery and antimicrobial activity of ciprofloxacin-grafted Ugi adducts

A new series of ciprofloxacin-derived Ugi adducts were rationally designed and synthesized. The synthesized molecules were explored for their potential antimicrobial activities against four pathogenic microorganisms. Among these derivatives, compound 7h with a 4-nitrophenyl substituent at R2 exhibited significant activity against two tested Gram-positive bacteria with a minimum inhibitory concentration value of 0.097 µg/mL while 7i bearing 4-chlorophenyl pendant demonstrated the best antimicrobial activities against Gram-negative bacteria. Furthermore, the analysis of the structure-activity relationships disclosed that types of substitutions differently affect the bacteria so the most potent derivative against Gram-negative infections was the least active one in Gram-positive microorganisms. Also, the molecular docking and molecular dynamic simulations were executed on 7i as the most potent Gram-negative anti-bacterial agent against ATP-binding sites of DNA gyrase B. Accordingly, our findings suggest that ciprofloxacin-based Ugi adducts are an interesting precursor for the design of potent antimicrobial agents.Communicated by Ramaswamy H. Sarma.

Phosphoethanolamine Transferases as Drug Discovery Targets for Therapeutic Treatment of Multi-Drug Resistant Pathogenic Gram-Negative Bacteria

Antibiotic resistance caused by multidrug-resistant (MDR) bacteria is a major challenge to global public health. Polymyxins are increasingly being used as last-in-line antibiotics to treat MDR Gram-negative bacterial infections, but resistance development renders them ineffective for empirical therapy. The main mechanism that bacteria use to defend against polymyxins is to modify the lipid A headgroups of the outer membrane by adding phosphoethanolamine (PEA) moieties. In addition to lipid A modifying PEA transferases, Gram-negative bacteria possess PEA transferases that decorate proteins and glycans. This review provides a comprehensive overview of the function, structure, and mechanism of action of PEA transferases identified in pathogenic Gram-negative bacteria. It also summarizes the current drug development progress targeting this enzyme family, which could reverse antibiotic resistance to polymyxins to restore their utility in empiric therapy.

Surgical Antibiotic Prophylaxis Administration Improved after introducing Dedicated Guidelines: A Before-and-After Study from Dhulikhel Hospital in Nepal (2019-2023)

(1) Background: Surgical antibiotic prophylaxis (SAP) is important for reducing surgical site infections. The development of a dedicated hospital SAP guideline in the Dhulikhel Hospital was a recommendation from a baseline study on SAP compliance. Compliance with this new guideline was enhanced through the establishment of a hospital committee, the establishment of an antibiotic stewardship program and the funding and training of healthcare professionals. Using the baseline and a follow-up study after introducing dedicated hospital SAP guidelines, we compared: (a) overall compliance with the SAP guidelines and (b) the proportion of eligible and non-eligible patients who received initial and redosing of SAP; (2) Methods: A before-and-after cohort study was conducted to compare SAP compliance between a baseline study (July 2019-December 2019) and a follow-up study (January 2023-April 2023); (3) Results: A total of 874 patients were in the baseline study and 751 in the follow-up study. Overall SAP compliance increased from 75% (baseline) to 85% in the follow-up study (p < 0.001). Over 90% of those eligible for the initial dose of SAP received it in both studies. Inappropriate use for those not eligible for an initial dose was reduced from 50% to 38% (p = 0.04). For those eligible for redosing, this increased from 14% to 22% but was not statistically significant (p = 0.272); (4) Conclusions: Although there is room for improvement, introduction of dedicated SAP guidelines was associated with improved overall SAP compliance. This study highlights the role of operational research in triggering favorable interventions in hospital clinical care.

Genetic Engineering and Biosynthesis Technology: Keys to Unlocking the Chains of Phage Therapy

Phages possess the ability to selectively eliminate pathogenic bacteria by recognizing bacterial surface receptors. Since their discovery, phages have been recognized for their potent bactericidal properties, making them a promising alternative to antibiotics in the context of rising antibiotic resistance. However, the rapid emergence of phage-resistant strains (generally involving temperature phage) and the limited host range of most phage strains have hindered their antibacterial efficacy, impeding their full potential. In recent years, advancements in genetic engineering and biosynthesis technology have facilitated the precise engineering of phages, thereby unleashing their potential as a novel source of antibacterial agents. In this review, we present a comprehensive overview of the diverse strategies employed for phage genetic engineering, as well as discuss their benefits and drawbacks in terms of bactericidal effect.

The need for Africa to develop capacity for vaccinology as a means of curbing antimicrobial resistance

The high prevalence of infectious diseases in Africa, combined with weak healthcare systems, poor antimicrobial stewardship, and an unchecked drug supply chain, is steadily reversing the trend in the fight against infectious diseases in this part of the world, posing severe threats to antimicrobial resistance (AMR). AMR continuously evolves and threatens to undermine antimicrobial efficacy and undo advances against infectious diseases. This brewing pandemic is now recognized as a significant worldwide health danger, implicated in several cases of morbidity, mortality, and increasing healthcare costs. Vaccine technology has been proven to be the principal remedy to this imminent danger since it prevents microbial infections. However, since Africa cannot produce its vaccines, it relies on external sources and, as a result, it is significantly affected by vaccine nationalism, hoarding, and instabilities in global supply chains. This has further adversely impacted the ability of African governments to regulate rollouts, protect their citizens, and ultimately rejoin the global economy. This dependency is a severe challenge to Africa's health resilience, as it is unsustainable. Given the inevitability of potential global pandemics and the alarming incidences of multi-drug resistance infections reported daily, Africa must develop the capability to produce its vaccines. The review utilized a systematic search of academic databases and grey literature, as well as a manual search of relevant reports and articles. In this review, we outline the public health threats and concerns that AMR poses to Africans, and the hurdles and advances achieved in vaccine development over the years. We also highlight possible strategies, particularly collaborative efforts, that will accelerate vaccine production and ease the strain of infectious diseases and antimicrobial resistance in Africa. Key findings indicate that Africa has significant gaps in its vaccine manufacturing and distribution capacity, with only a few countries having the ability to produce vaccines. Additionally, existing vaccine production facilities are often outdated and require significant investment to meet international standards. The review also highlights successful initiatives in Africa, such as the mRNA vaccine hub and the African Vaccine Manufacturing Initiative, which have demonstrated the potential for building local vaccine manufacturing capacity. The study concludes that Africa needs to prioritize investment in vaccine research and development, regulatory capacity, and infrastructure to build a sustainable vaccine manufacturing ecosystem. Overall, this review emphasizes the urgent need for Africa to develop its vaccine manufacturing capacity to improve vaccine access and strengthen its ability to respond to future pandemics. The findings underscore the importance of collaboration between African governments, international organizations, and the private sector to build a resilient vaccine ecosystem in Africa.

Microbiota present in combined endodontic-periodontal diseases and its risks for endocarditis

INTRODUCTION

Infective endocarditis (IE) is an inflammatory disease usually caused by bacteria that enter the bloodstream and establish infections in the inner linings or valves of the heart, including blood vessels. Despite the availability of modern antimicrobial and surgical treatments, IE continues to cause substantial morbidity and mortality. Oral microbiota is considered one of the most significant risk factors for IE. The objective of this study was to evaluate the microbiota present in root canal (RC) and periodontal pocket (PP) clinical samples in cases with combined endo-periodontal lesions (EPL) to detect species related to IE using NGS.

METHODS

Microbial samples were collected from 15 RCs and their associated PPs, also from 05 RCs with vital pulp tissues (negative control, NC). Genomic studies associated with bioinformatics, combined with structuring of a database (genetic sequences of bacteria reported for infective endocarditis), allowed for the assessment of the microbial community at both sites. Functional prediction was conducted using PICRUSt2.

RESULTS

Parvimonas, Streptococcus, and Enterococcus were the major genera detected in the RCs and PPs. A total of 79, 96, and 11 species were identified in the RCs, PPs, and NCs, respectively. From them, a total of 34 species from RCs, 53 from PPs, and 2 from NCs were related to IE. Functional inference demonstrated that CR and PP microbiological profiles may not be the only risk factors for IE but may also be associated with systemic diseases, including myocarditis, human cytomegalovirus infection, bacterial invasion of epithelial cells, Huntington's disease, amyotrophic lateral sclerosis, and hypertrophic cardiomyopathy. Additionally, it was possible to predict antimicrobial resistance variants for broad-spectrum drugs, including ampicillin, tetracycline, and macrolides.

CONCLUSION

Microorganisms present in the combined EPL may not be the only risk factor for IE but also for systemic diseases. Antimicrobial resistance variants for broad-spectrum drugs were inferred based on PICRUSt-2. State-of-the-art sequencing combined with bioinformatics has proven to be a powerful tool for conducting studies on microbial communities and could considerably assist in the diagnosis of serious infections.

CLINICAL RELEVANCE

Few studies have investigated the microbiota in teeth compromised by combined endo-periodontal lesions (EPL), but none have correlated the microbiological findings to any systemic condition, particularly IE, using NGS techniques. In such cases, the presence of apical periodontitis and periodontal disease can increase IE risk in susceptible patients.

Orally delivered single-domain antibodies against gastrointestinal pathogens

Single-domain antibodies (sdAbs) are exceptionally stable fragments derived from the antigen-binding domains of immunoglobulins. They can withstand extreme pH, high temperature, and proteolysis, making them suitable for controlling gastrointestinal (GI) infections in humans and animals. sdAbs may function in their native soluble form, although different derived protein formats and the use of delivery vehicles can be useful for improved oral delivery. We discuss selected examples of the use of orally delivered sdAbs for protecting humans and animals against GI infections caused by pathogenic bacteria, viruses, and parasites. We finally provide perspectives on how sdAbs may be applied industrially and what challenges should be overcome for orally delivered sdAbs to reach the market.

Knowledge, Attitudes, and Practices Regarding Antibiotic Use and Resistance: A Cross-Sectional Study among Students in Israel

Antibiotic resistance is one of the biggest threats to human health, food security, and development. This study aimed to examine the level of knowledge and awareness regarding antibiotic resistance while comparing students from health sciences to students in other disciplines. A cross-sectional study was conducted based on the "antibiotic resistance" questionnaire developed by the World Health Organization. A total of 371 students participated in the study. All respondents had taken antibiotics in the past. A tenth had taken them on their own without a prescription, and 14% had not received an explanation regarding the use of antibiotics. The average for the knowledge questions was 15.49 ± 5.35 (out of 27). Many students mistakenly associated antibiotics with viral diseases. Despite these misconceptions, there was a high level of awareness and understanding regarding the ways to treat antibiotic resistance. Still, the awareness of the severity of antibiotic resistance was not high. Differences were found between the disciplines in general knowledge and the level of awareness and understanding about the ways to treat antibiotic resistance, where health science students had the highest scores, followed by social science students and finally, computer and management students. No differences were found in the perception of the severity of the phenomenon. This information is essential to developing educational interventions to improve knowledge, attitudes, and practices regarding antibiotic use among students, especially those unrelated to the health sciences.

The global antimicrobial resistance response effort must not exclude marginalised populations

Antimicrobial resistance (AMR), a rising global health crisis causing about 700,000 deaths annually and potentially 10 million deaths by 2050, disproportionately impacts marginalised populations. Due to socioeconomic, ethnic, geographic, and other barriers, these communities often have restricted healthcare access, compounding the AMR threat. Unequal access to effective antibiotics, inadequate living conditions, and a lack of awareness exacerbate the crisis in marginalised communities, making them more susceptible to AMR. A broader, inclusive response is needed to ensure equitable access to antibiotics, improved living conditions, education, and policy changes to challenge the root socio-economic disparities. Ignoring marginalised populations in the fight against AMR is both a moral and strategic failure. Therefore, inclusivity must be a central tenet in combating AMR. This article not only critically dissects this prevailing oversight but also urgently calls for comprehensive action to address this significant shortcoming in our response efforts.

A method to determine two antibiotics prescribed to treat nosocomial infections in plasma and urine by micellar liquid chromatography

Combined prescription of the antimicrobial drugs linezolid and meropenem is a common strategy to treat multidrug-resistant nosocomial infections. We propose an innovative method to determine these two drugs in plasma and urine, based on micellar liquid chromatography. Both biological fluids were diluted in mobile phase, filtered and directly injected, without any extraction step. Using a C18 column and a mobile phase of 0.1 M sodium dodecyl sulfate - 10 % methanol, phosphate buffered at pH 3, running under isocratic mode, both antibiotics were eluted without overlapping in<15 min. Detection was by absorbance: 255 nm for linezolid and 310 nm for meropenem. The influence of sodium dodecyl sulfate and methanol concentration on retention factor was established for both drugs using an interpretative approach assisted by chemometrics. The procedure was successfully validated following the guidelines of 2018 Bioanalytical Method Validation Guidance for Industry in terms of: linearity (determination coefficients over 0.99990), calibration range (1 - 50 mg/L), instrumental and method sensitivity, trueness (bias of -10.8 to + 2.4%), precision (relative standard deviation of < 10.2%), dilution integrity, carry-over effect, robustness and stability. It should be emphasized that the method uses low volumes of toxic and volatile solvents and can be achieved in a short period. The procedure was found useful for routine analysis, as it was cost-affordable, more eco-friendly and safer than hydroorganic HPLC, easy-to-handle and highly sample-throughput. Finally, it was applied to incurred samples of patients taking this medication.

Characterization and Engineering Studies of a New Endolysin from the Propionibacterium acnes Bacteriophage PAC1 for the Development of a Broad-Spectrum Artilysin with Altered Specificity

The emergence of multidrug-resistant (MDR) bacteria has risen rapidly, leading to a great threat to global public health. A promising solution to this problem is the exploitation of phage endolysins. In the present study, a putative N-acetylmuramoyl-L-alanine type-2 amidase (NALAA-2, EC 3.5.1.28) from Propionibacterium bacteriophage PAC1 was characterized. The enzyme (PaAmi1) was cloned into a T7 expression vector and expressed in E. coli BL21 cells. Kinetics analysis using turbidity reduction assays allowed the determination of the optimal conditions for lytic activity against a range of Gram-positive and negative human pathogens. The peptidoglycan degradation activity of PaAmi1 was confirmed using isolated peptidoglycan from P. acnes. The antibacterial activity of PaAmi1 was investigated using live P. acnes cells growing on agar plates. Two engineered variants of PaAmi1 were designed by fusion to its N-terminus two short antimicrobial peptides (AMPs). One AMP was selected by searching the genomes of Propionibacterium bacteriophages using bioinformatics tools, whereas the other AMP sequence was selected from the antimicrobial peptide databases. Both engineered variants exhibited improved lytic activity towards P. acnes and the enterococci species Enterococcus faecalis and Enterococcus faecium. The results of the present study suggest that PaAmi1 is a new antimicrobial agent and provide proof of concept that bacteriophage genomes are a rich source of AMP sequences that can be further exploited for designing novel or improved endolysins.

An overview on the antibacterial properties of juglone, naphthazarin, plumbagin and lawsone derivatives and their metal complexes

Bacterial resistance development represents a serious threat to human health across the globe and has become a very serious clinical problem for many classes of antibiotics. Hence, there is a constant and urgent need for the discovery and development of new effective antibacterial agents to stem the emergence of resistant bacteria. 1,4-naphthoquinones are an important class of natural products and have been known for decades as a privileged scaffold in medicinal chemistry regarding their many biological properties. The significant biological properties of specific 1,4-naphthoquinones hydroxyderivatives have drawn the attention of researchers in order to find new derivatives with an optimized activity, mainly as antibacterial agents. Based on juglone, naphthazarin, plumbagin and lawsone moieties, structural optimization was realized with the purpose of improving the antibacterial activity. Thereupon, relevant antibacterial activities have been observed on different panels of bacterial strains including resistant ones. In this review, we highlight the interest of developing new 1,4-naphthoquinones hydroxyderivatives and some metal complexes as promising antibacterial agents alternatives. Here, we thoroughly report for the first time both the antibacterial activity and the chemical synthesis of four different 1,4-naphthoquinones (juglone, naphthazarin, plumbagin and lawsone) from 2002 to 2022 with an emphasis on the structure-activity relationship, when applicable.

Occurrence and Treatment of Antibiotic-Resistant Bacteria Present in Surface Water

According to the World Health Organization, antibiotic resistance is one of the main threats to global health. The excessive use of several antibiotics has led to the widespread distribution of antibiotic-resistant bacteria and antibiotic resistance genes in various environment matrices, including surface water. In this study, total coliforms, Escherichia coli and enterococci, as well as total coliforms and Escherichia coli resistant to ciprofloxacin, levofloxacin, ampicillin, streptomycin, and imipenem, were monitored in several surface water sampling events. A hybrid reactor was used to test the efficiency of membrane filtration, direct photolysis (using UV-C light emitting diodes that emit light at 265 nm and UV-C low pressure mercury lamps that emit light at 254 nm), and the combination of both processes to ensure the retention and inactivation of total coliforms and Escherichia coli as well as antibiotic-resistant bacteria (total coliforms and Escherichia coli) present in river water at occurrence levels. The membranes used (unmodified silicon carbide membranes and the same membrane modified with a photocatalytic layer) effectively retained the target bacteria. Direct photolysis using low-pressure mercury lamps and light-emitting diode panels (emitting at 265 nm) achieved extremely high levels of inactivation of the target bacteria. The combined treatment (unmodified and modified photocatalytic surfaces in combination with UV-C and UV-A light sources) successfully retained the bacteria and treated the feed after 1 h of treatment. The hybrid treatment proposed is a promising approach to use as point-of-use treatment by isolated populations or when conventional systems and electricity fail due to natural disasters or war. Furthermore, the effective treatment obtained when the combined system was used with UV-A light sources indicates that the process may be a promising approach to guarantee water disinfection using natural sunlight.

Vaccine development for bacterial pathogens: Advances, challenges and prospects

The advent and use of antimicrobials have played a key role in treating potentially life-threatening infectious diseases, improving health, and saving the lives of millions of people worldwide. However, the emergence of multidrug resistant (MDR) pathogens has been a significant health challenge that has compromised the ability to prevent and treat a wide range of infectious diseases that were once treatable. Vaccines offer potential as a promising alternative to fight against antimicrobial resistance (AMR) infectious diseases. Vaccine technologies include reverse vaccinology, structural biology methods, nucleic acid (DNA and mRNA) vaccines, generalised modules for membrane antigens, bioconjugates/glycoconjugates, nanomaterials and several other emerging technological advances that are offering a potential breakthrough in the development of efficient vaccines against pathogens. This review covers the opportunities and advancements in vaccine discovery and development targeting bacterial pathogens. We reflect on the impact of the already-developed vaccines targeting bacterial pathogens and the potential of those currently under different stages of preclinical and clinical trials. More importantly, we critically and comprehensively analyse the challenges while highlighting the key indices for future vaccine prospects. Finally, the issues and concerns of AMR for low-income countries (sub-Saharan Africa) and the challenges with vaccine integration, discovery and development in this region are critically evaluated.

A Novel Strategy for the Design of Aurein 1.2 Analogs with Enhanced Bioactivities by Conjunction of Cell-Penetrating Regions

The rational design modification of membrane-active peptide structures by introducing additional membrane-penetrating regions has become a good strategy for the improvement of action and potency. Aurein 1.2 (GLFDIIKKIAESF-NH₂) is a multifunctional antimicrobial peptide isolated from the green and golden bell frog, Litoria aurea, and the southern bell frog Litoria raniformis skin secretions. Its bio-functionality has been widely investigated. However, its lack of a potent action failed to provide aurein 1.2 with a competitive edge for further development as a therapeutic agent for clinical use. Herein, aurein 1.2 was chosen as a template for rational modification to achieve a more potent bio-functionality. KLA-2 (GLFDIIKKLAKLAESF-NH₂), which a double KLA region inserted into the sequence, presented a 2-16-fold enhancement of antimicrobial activity, a 2-8-fold greater anti-biofilm activity (including biofilm prevention and eradication), and a 7-fold more potent anti-proliferation activity and hence was regarded as the most broad-spectrum active peptide. Additionally, with respect to antimicrobial activity, the IIKK-modified analog, IK-3 (GLFDIIKKIIKKIIKKI-NH₂), also demonstrated a potent enhancement of activity against various pathogens, exhibiting a 2-8-fold enhanced activity compared to the parent peptide. Moreover, the selectivities of KLA-1 and KLA-2 were enhanced significantly. In conclusion, peptide modification, through the introduction of additional membrane penetrating regions, can increase both the potency and activity spectra of natural template peptides, making them suitable candidates for new drug development.

MRSA compendium of epidemiology, transmission, pathophysiology, treatment, and prevention within one health framework

Staphylococcus aureus is recognized as commensal as well as opportunistic pathogen of humans and animals. Methicillin resistant strain of S. aureus (MRSA) has emerged as a major pathogen in hospitals, community and veterinary settings that compromises the public health and livestock production. MRSA basically emerged from MSSA after acquiring SCCmec element through gene transfer containing mecA gene responsible for encoding PBP-2α. This protein renders the MRSA resistant to most of the β-lactam antibiotics. Due to the continuous increasing prevalence and transmission of MRSA in hospitals, community and veterinary settings posing a major threat to public health. Furthermore, high pathogenicity of MRSA due to a number of virulence factors produced by S. aureus along with antibiotic resistance help to breach the immunity of host and responsible for causing severe infections in humans and animals. The clinical manifestations of MRSA consist of skin and soft tissues infection to bacteremia, septicemia, toxic shock, and scalded skin syndrome. Moreover, due to the increasing resistance of MRSA to number of antibiotics, there is need to approach alternatives ways to overcome economic as well as human losses. This review is going to discuss various aspects of MRSA starting from emergence, transmission, epidemiology, pathophysiology, disease patterns in hosts, novel treatment, and control strategies.

Nano-functionalization and evaluation of antimicrobial activity of Tinospora cordifolia against the TolB protein of Pseudomonas aeruginosa - An antibacterial and computational study

Introduction

Antibacterial drug resistance, brought on by the overuse of antibiotics, is one of the biggest threats to human health. It is crucial to consider cutting-edge strategies, such as herbal remedies, to control multidrug-resistant (MDR) bacteria.

Methods

This study evaluated the phytochemical, antioxidant and antibacterial properties of the various Tinospora cordifolia extracts. Functionalization of the isolated active compound was done using gold (Au) and silver (Ag) nanoparticles (NPs). Further, to understand the interaction of the isolated class, Cordifolisides, with its target, various in-silico methods were used.

Results and Discussion

The plant was reported from the Charaideo district of Assam, whose methanolic stem extract showed the maximum activity towards the nosocomial pathogen Pseudomonas aeruginosa. Consequently, the active compound was isolated and characterized as belonging to the class Cordifoliside using NMR. The AuNPs and AgNPs functionalized isolates showed enhanced antimicrobial activity against P. aeruginosa compared to the unfunctionalized isolate. The most reactive compound, Cordifoliside C was determined using Density Functional Theory (DFT) analysis, whose interactions with the TolB protein were studied using molecular docking methods, which revealed good binding interactions of Cordifoliside C with the TolB protein.

Conclusion

This study offers enormous potential for drug design and might be used as a pipeline to address the urgent problem of multidrug-resistance in bacteria. Graphical Abstract.

Available evidence and potential for vaccines for reduction in antibiotic prescriptions

Bacterial antibiotic resistance is a public health issue. It means that drugs become ineffective, infections persist and have a huge impact on the health of patients and their spreading increases. To address a complex threat such as bacterial antibiotic resistance different and integrated approaches are needed including discovery of new antibiotics, improvement of diagnostics tools and improvement of antibiotic stewardship. Absolutely relevant are prevention of infections as well as decrease in the use of antibiotics. Vaccines are an important tool in the fight against bacterial antibiotic resistance and can help prevent it in several ways. Indeed, vaccines are highly effective in preventing diseases that might otherwise require the use of antibiotics to treat symptoms and associated complications. Preventing infections through vaccination helps reduce the need for and widespread and inappropriate use of antibiotics, including for secondary bacterial infections.

New putative therapeutic targets against Serratia marcescens using reverse vaccinology and subtractive genomics

The Gram-negative bacillus Serratia marcescens, a member of Enterobacteriaceae family, is an opportunistic nosocomial pathogen commonly found in hospital outbreaks that can cause infections in the urinary tract, bloodstream, central nervous system and pneumonia. Because S. marcescens strains are resistant to several antibiotics, it is critical the need for effective treatments, including new drugs and vaccines. Here, we applied reverse vaccinology and subtractive genomic approaches for the in silico prediction of potential vaccine and drug targets against 59 strains of S. marcescens. We found 759 core non-host homologous proteins, of which 87 are putative surface-exposed proteins, 183 secreted proteins, and 80 membrane proteins. From these proteins, we predicted seven candidates vaccine targets: a sn-glycerol-3-phosphate-binding periplasmic protein UgpB, a vitamin B12 TonB-dependent receptor, a ferrichrome porin FhuA, a divisome-associated lipoprotein YraP, a membrane-bound lytic murein transglycosylase A, a peptidoglycan lytic exotransglycosylase, and a DUF481 domain-containing protein. We also predicted two drug targets: a N(4)-acetylcytidine amidohydrolase, and a DUF1428 family protein. Using the molecular docking approach for each drug target, we identified and selected ZINC04259491 and ZINC04235390 molecules as the most favorable interactions with the target active site residues. Our findings may contribute to the development of vaccines and new drug targets against S. marcescens. Communicated by Ramaswamy H. Sarma.

Awareness of Antibiotics and Antibiotic Resistance in a Rural District of Ha Nam Province, Vietnam: A Cross-Sectional Survey

Low awareness of antibiotics and antibiotic resistance may lead to inappropriate antibiotic use and contribute to the problem of antibiotic resistance. This study explored levels and determinants of antibiotic awareness in a rural community in northern Vietnam, through a cross-sectional survey of 324 households in one commune of Ha Nam Province. Awareness and knowledge of antibiotics and antibiotic resistance and determinants were evaluated using structured questionnaires. Most respondents (232/323 (71.8%)) had heard of antibiotics, but fewer could name any antibiotic (68/323 (21.1%)) or had heard of antibiotic resistance (57/322 (17.7%)). In adjusted regression models, antibiotic awareness was lower among those who lived further from health facilities (Odds Ratio (OR): 0.08; 95% Confidence Interval (CI): 0.04-0.19) but higher among those who used interpersonal sources for health information (OR: 4.06; 95% CI: 1.32-12.46). Antibiotic resistance awareness was lower among those who used private providers or pharmacies as their usual health facility (OR: 0.14; 95% CI: 0.05-0.44) but higher among those with medical insurance (OR: 3.70; 95% CI: 1.06-12.96) and those with high media use frequency (OR: 9.54; 95% CI: 2.39-38.07). Awareness of Antimicrobial Resistance (AMR) was also higher among those who sought health information from official sources (OR: 3.88; 95% CI: 1.01-14.86) or had overall high levels of health information seeking (OR: 12.85; 95% CI: 1.63-101.1). In conclusion, communication interventions need to target frequently used media platforms, such as television, as well as key health information providers, such as health workers, as channels for increasing knowledge and changing community antibiotic use behaviour.

Reverse engineering approach: a step towards a new era of vaccinology with special reference to Salmonella

INTRODUCTION

Salmonella is responsible for causing enteric fever, septicemia, and gastroenteritis in humans. Due to high disease burden and emergence of multi- and extensively drug-resistant Salmonella strains, it is becoming difficult to treat the infection with existing battery of antibiotics as we are not able to discover newer antibiotics at the same pace at which the pathogens are acquiring resistance. Though vaccines against Salmonella are available commercially, they have limited efficacy. Advancements in genome sequencing technologies and immunoinformatics approaches have solved the problem significantly by giving rise to a new era of vaccine designing, i.e. 'Reverse engineering.' Reverse engineering/vaccinology has expedited the vaccine identification process. Using this approach, multiple potential proteins/epitopes can be identified and constructed as a single entity to tackle enteric fever.

AREAS COVERED

This review provides details of reverse engineering approach and discusses various protein and epitope-based vaccine candidates identified using this approach against typhoidal Salmonella.

EXPERT OPINION

Reverse engineering approach holds great promise for developing strategies to tackle the pathogen(s) by overcoming the limitations posed by existing vaccines. Progressive advancements in the arena of reverse vaccinology, structural biology, and systems biology combined with an improved understanding of host-pathogen interactions are essential components to design new-generation vaccines.

Highly different effects of phage therapy and antibiotic therapy on immunological responses of chickens infected with Salmonella enterica serovar Typhimurium

The appearance of bacteria resistant to most or even all known antibiotics has become a serious medical problem. One such promising and effective alternative form of therapy may be the use of phages, the administration of which is considered to be safe and highly effective, especially in animals with drug-resistant infections. Although there have been no reports to date suggesting that bacteriophages can cause any severe complications or adverse effects, we still know little about their interactions with animal organisms, especially in the context of the functioning of the immune system. Therefore, the aim of the present study was to compare the impact of the application of selected bacteriophages and antibiotics (enrofloxacin and colistin), commonly used in veterinary medicine, on immune functions in Salmonella enterica serovar Typhimurium-infected chickens. The birds were infected with S. Typhimurium and then treated with a phage cocktail (14 days), enrofloxacin (5 days), or colistin (5 days). The concentrations of a panel of pro-inflammatory cytokines (IL-1β, IL-6, IFN-γ, IL-8, and IL-12) and cytokines that reveal anti-inflammatory effects (IL-10 and IL-4), the percentage of lymphocytes, and the level of stress hormones (corticosterone and cortisol), which significantly modulate the immune responses, were determined in different variants of the experiment. The phage cocktail revealed anti-inflammatory effects when administered either 1 day after infection or 2 days after S. Typhimurium detection in feces, as measured by inhibition of the increase in levels of inflammatory response markers (IL-1β, IL-6, IFN-γ, IL-8, and IL-12). This was also confirmed by increased levels of cytokines that exert an anti-inflammatory action (IL-10 and IL-4) following phage therapy. Moreover, phages did not cause a negative effect on the number and activity of lymphocytes’ subpopulations crucial for normal immune system function. These results indicate for the first time that phage therapy not only is effective but also can be used in veterinary medicine without disturbing immune homeostasis, expressed as cytokine imbalance, disturbed percentage of key immune cell subpopulations, and stress axis hyperactivity, which were observed in our experiments as adverse effects accompanying the antibiotic therapy.

Recent Advances in Multifunctional Antimicrobial Peptides as Immunomodulatory and Anticancer Therapy: Chromogranin A-Derived Peptides and Dermaseptins as Endogenous versus Exogenous Actors

Antimicrobial peptides (AMPs) are produced by all living organisms exhibiting antimicrobial activities and representing the first line of innate defense against pathogens. In this context, AMPs are suggested as an alternative to classical antibiotics. However, several researchers reported their involvement in different processes defining them as Multifunctional AMPs (MF-AMPs). Interestingly, these agents act as the endogenous responses of the human organism against several dangerous stimuli. Still, they are identified in other organisms and evaluated for their anticancer therapy. Chromogranin A (CgA) is a glyco-phosphoprotein discovered for the first time in the adrenal medulla but also produced in several cells. CgA can generate different derived AMPs influencing numerous physiological processes. Dermaseptins (DRSs) are a family of α-helical-shaped polycationic peptides isolated from the skin secretions of several leaf frogs from the Phyllomedusidae family. Several DRSs were identified as AMPs and, until now, more than 65 DRSs have been classified. Recently, these exogenous molecules were characterized for their anticancer activity. In this review, we summarize the role of these two classes of MF-AMPs as an example of endogenous molecules for CgA-derived peptides, able to modulate inflammation but also as exogenous molecules for DRSs, exerting anticancer activities.

Bioselectivity of silk protein-based materials and their bio-inspired applications

Adhesion to material surfaces is crucial for almost all organisms regarding subsequent biological responses. Mammalian cell attachment to a surrounding biological matrix is essential for maintaining their survival and function concerning tissue formation. Conversely, the adhesion and presence of microbes interferes with important multicellular processes of tissue development. Therefore, tailoring bioselective, biologically active, and multifunctional materials for biomedical applications is a modern focus of biomaterial research. Engineering biomaterials that stimulate and interact with cell receptors to support binding and subsequent physiological responses of multicellular systems attracted much interest in the last years. Further to this, the increasing threat of multidrug resistance of pathogens against antibiotics to human health urgently requires new material concepts for preventing microbial infestation and biofilm formation. Thus, materials exhibiting microbial repellence or antimicrobial behaviour to reduce inflammation, while selectively enhancing regeneration in host tissues are of utmost interest. In this context, protein-based materials are interesting candidates due to their natural origin, biological activity, and structural properties. Silk materials, in particular those made of spider silk proteins and their recombinant counterparts, are characterized by extraordinary properties including excellent biocompatibility, slow biodegradation, low immunogenicity, and non-toxicity, making them ideally suited for tissue engineering and biomedical applications. Furthermore, recombinant production technologies allow for application-specific modification to develop adjustable, bioactive materials. The present review focusses on biological processes and surface interactions involved in the bioselective adhesion of mammalian cells and repellence of microbes on protein-based material surfaces. In addition, it highlights the importance of materials made of recombinant spider silk proteins, focussing on the progress regarding bioselectivity.

A new self-immolative colistin prodrug with dual targeting functionalities and reduced toxicity for the treatment of intracellular bacterial infections

Colistin is a potent antibiotic but its severe side effects including nephrotoxicity and neurotoxicity are the roadblock for their wide use in clinics. To solve this problem, we synthesized a new prodrug, mannose-maltose-colistin conjugate, termed MMCC that can reversibly mask the five amines of colistin that are primarily responsible for the toxicity. The deliberated design of disulfide-based self-immolative linker warranted the reversibly release of the pristine amines of colistin on demand without sacrificing antimicrobial efficacy. Once MMCC was delivered in cells, reducing agents cleaves the disulfide bond and release the pristine amines. The targeting ligands of maltose and mannose were grafted on colistin conjugate for targeting delivery of colistin to bacteria and macrophages, respectively. Taken together, MMCC as a new class of antimicrobial biomaterials, demonstrates its great potential for the treatment of intracellular bacterial infections.

Nanocarriers for effective delivery: modulation of innate immunity for the management of infections and the associated complications

Innate immunity is the first line of defense against invading pathogens. Innate immune cells can recognize invading pathogens through recognizing pathogen-associated molecular patterns (PAMPs) via pattern recognition receptors (PRRs). The recognition of PAMPs by PRRs triggers immune defense mechanisms and the secretion of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. However, sustained and overwhelming activation of immune system may disrupt immune homeostasis and contribute to inflammatory disorders. Immunomodulators targeting PRRs may be beneficial to treat infectious diseases and their associated complications. However, therapeutic performances of immunomodulators can be negatively affected by (1) high immune-mediated toxicity, (2) poor solubility and (3) bioactivity loss after long circulation. Recently, nanocarriers have emerged as a very promising tool to overcome these obstacles owning to their unique properties such as sustained circulation, desired bio-distribution, and preferred pharmacokinetic and pharmacodynamic profiles. In this review, we aim to provide an up-to-date overview on the strategies and applications of nanocarrier-assisted innate immune modulation for the management of infections and their associated complications. We first summarize examples of important innate immune modulators. The types of nanomaterials available for drug delivery, as well as their applications for the delivery of immunomodulatory drugs and vaccine adjuvants are also discussed.

Repurposing Dimetridazole and Ribavirin to disarm Pseudomonas aeruginosa virulence by targeting the quorum sensing system

Pseudomonas aeruginosa relies on its complex cellular regulatory network to produce a series of virulence factors and to cause various acute and chronic infections in a wide range of hosts. Compared with traditional antibiotics which frequently accompany with widespread antibiotic resistance, crippling the virulence system of bacteria is expected to be a promising anti-infective strategy. In this study, Dimetridazole and Ribavirin, which had poor antibacterial activities on P. aeruginosa reference isolate PAO1 in nutrient medium but significantly inhibited the growth of P. aeruginosa PAO1 in M9-adenosine, were selected from 40 marketed compounds with similar core structure (furan, benzofuran, or flavonoids) to the acyl-homoserine lactone signals of P. aeruginosa quorum sensing (QS) system. The production of QS-controlled proteases, pyocyanin, and biofilm formation of P. aeruginosa PAO1 and the clinical isolates were significantly decreased by the presence of Dimetridazole or Ribavirin. Correspondingly, the majority of QS-activated genes in P. aeruginosa, including the key regulatory genes lasR, rhlR, and pqsR and their downstream genes, were significantly inhibited by Ribavirin or Dimetridazole, as determined by RNA-sequencing and quantitative PCR. Furthermore, the susceptibilities of drug-resistant P. aeruginosa isolates to polymyxin B, meropenem, and kanamycin were remarkably promoted by the synergistic application of Dimetridazole or Ribavirin. Finally, the treatment of Ribavirin or Dimetridazole effectively protected Caenorhabditis elegans and mice from P. aeruginosa infection. In conclusion, this study reports the antivirulence potentials of Dimetridazole and Ribavirin on P. aeruginosa and provides structural basis and methodological reference for the development of anti-pseudomonal drugs.

Neighborhood-based inference and restricted Boltzmann machine for microbe and drug associations prediction

Background

Efficient identification of microbe-drug associations is critical for drug development and solving problem of antimicrobial resistance. Traditional wet-lab method requires a lot of money and labor in identifying potential microbe-drug associations. With development of machine learning and publication of large amounts of biological data, computational methods become feasible.

Methods

In this article, we proposed a computational model of neighborhood-based inference (NI) and restricted Boltzmann machine (RBM) to predict potential microbe-drug association (NIRBMMDA) by using integrated microbe similarity, integrated drug similarity and known microbe-drug associations. First, NI was used to obtain a score matrix of potential microbe-drug associations by using different thresholds to find similar neighbors for drug or microbe. Second, RBM was employed to obtain another score matrix of potential microbe-drug associations based on contrastive divergence algorithm and sigmoid function. Because generalization ability of individual method is poor, we used an ensemble learning to integrate two score matrices for predicting potential microbe-drug associations more accurately. In particular, NI can fully utilize similar (neighbor) information of drug or microbe and RBM can learn potential probability distribution hid in known microbe-drug associations. Moreover, ensemble learning was used to integrate individual predictor for obtaining a stronger predictor.

Results

In global leave-one-out cross validation (LOOCV), NIRBMMDA gained the area under the receiver operating characteristics curve (AUC) of 0.8666, 0.9413 and 0.9557 for datasets of DrugVirus, MDAD and aBiofilm, respectively. In local LOOCV, AUCs of 0.8512, 0.9204 and 0.9414 were obtained for NIRBMMDA based on datasets of DrugVirus, MDAD and aBiofilm, respectively. For five-fold cross validation, NIRBMMDA acquired AUC and standard deviation of 0.8569 ± -0.0027, 0.9248 ± -0.0014 and 0.9369 ± -0.0020 on the basis of datasets of DrugVirus, MDAD and aBiofilm, respectively. Moreover, case study for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) showed that 13 out of the top 20 predicted drugs were verified by searching literature. The other two case studies indicated that 17 and 17 out of the top 20 predicted microbes for the drug of ciprofloxacin and minocycline were confirmed by identifying published literature, respectively.

Microwaves, a potential treatment for bacteria: A review

Bacteria have brought great harm to the public, especially after the emergence of multidrug-resistant bacteria. This has rendered traditional antibiotic therapy ineffective. In recent years, hyperthermia has offered new treatments to remove bacteria. Microwaves (MW) are a component of the electromagnetic spectrum and can rapidly heat materials. Taking advantage of this characteristic of MW, related studies have shown that both thermal and non-thermal effects of MW can inactivate various bacteria. Even though the understanding of MW in the field of bacteria is not sufficient for widespread use at present, MW has performed well in dealing with microorganisms and controlling infection. This review will focus on the application of MW in bacteria and discuss the advantages, prospects and challenges of using MW in the bacterial field.

Algal Phlorotannins as Novel Antibacterial Agents with Reference to the Antioxidant Modulation: Current Advances and Future Directions

The increasing drug resistance of infectious microorganisms is considered a primary concern of global health care. The screening and identification of natural compounds with antibacterial properties have gained immense popularity in recent times. It has previously been shown that several bioactive compounds derived from marine algae exhibit antibacterial activity. Similarly, polyphenolic compounds are generally known to possess promising antibacterial capacity, among other capacities. Phlorotannins (PTs), an important group of algae-derived polyphenolic compounds, have been considered potent antibacterial agents both as single drug entities and in combination with commercially available antibacterial drugs. In this context, this article reviews the antibacterial properties of polyphenols in brown algae, with particular reference to PTs. Cell death through various molecular modes of action and the specific inhibition of biofilm formation by PTs were the key discussion of this review. The synergy between drugs was also discussed in light of the potential use of PTs as adjuvants in the pharmacological antibacterial treatment.

Bacterial pigments: A colorful palette reservoir for biotechnological applications

Synthetic derivatives are currently used instead of pigments in many applicative fields, from food to feed, from pharmaceutical to diagnostic, from agronomy to industry. Progress in organic chemistry allowed to obtain rather cheap compounds covering the whole color spectrum. However, several concerns arise from this chemical approach, as it is mainly based on nonrenewable resources such as fossil oil, and the toxicity or carcinogenic properties of products and/or precursors may be harmful for personnel involved in the productive processes. In this scenario, microorganisms and their pigments represent a colorful world to discover and reconsider. Each living bacterial strain may be a source of secondary metabolites with peculiar functions. The aim of this review is to link the physiological role of bacterial pigments with their potential use in different biotechnological fields. This enormous potential supports the big challenge for the development of strategies useful to identify, produce, and purify the right pigment for the desired application. At the end of this ideal journey through the world of bacterial pigments, the attention will be focused on melanin compounds, whose production relies upon different techniques ranging from natural producers, heterologous hosts, or isolated enzymes. In a green workflow, the microorganisms represent the starting and final point of pigment production.