Impact of antibiotic restrictions: the pharmaceutical perspective

Ta4C3 Nanosheets as a Novel Therapeutic Platform for Photothermal-Driven ROS Scavenging and Immune Activation against Antibiotic-Resistant Infections in Diabetic Wounds

The accumulation of excessive reactive oxygen species (ROS) and recurrent infections with drug-resistant bacteria pose significant challenges in diabetic wound infections, often leading to impediments in wound healing. Addressing this, there is a critical demand for novel strategies dedicated to treating and preventing diabetic wounds infected with drug-resistant bacteria. Herein, 2D tantalum carbide nanosheets (Ta4C3 NSs) have been synthesized through an efficient and straightforward approach, leading to the development of a new, effective nanoplatform endowed with notable photothermal properties, biosafety, and diverse ROS scavenging capabilities, alongside immunogenic attributes for diabetic wound treatment and prevention of recurrent drug-resistant bacterial infections. The Ta4C3 NSs exhibit remarkable photothermal performance, effectively eliminating methicillin-resistant Staphylococcus aureus (MRSA) and excessive ROS, thus promoting diabetic wound healing. Furthermore, Ta4C3 NSs enhance dendritic cell activation, further triggering T helper 1 (TH1)/TH2 immune responses, leading to pathogen-specific immune memory against recurrent MRSA infections. This nanoplatform, with its significant photothermal and immunomodulatory effects, holds vast potential in the treatment and prevention of drug-resistant bacterial infections in diabetic wounds.

Antimicrobial sensitisers: Gatekeepers to avoid the development of multidrug-resistant bacteria

The resistance of multidrug-resistant bacteria to existing antibiotics forces the continued development of new antibiotics and antibacterial agents, but the high costs and long timeframe involved in the development of new agents renders the hope that existing antibiotics may again play a part. The "antibiotic adjuvant" is an indirect antibacterial strategy, but its vague concept has, in the past, limited the development speed of related drugs. In this review article, we put forward an accurate concept of a "non-self-antimicrobial sensitisers (NSAS)", to distinguish it from an "antibiotic adjuvant", and then discuss several scientific methods to restore bacterial sensitivity to antibiotics, and the sources and action mechanism of existing NSAS, in order to guide the development and further research of NSAS.

Antibacterial Activity and Untargeted Metabolomics Profiling of Acalypha arvensis Poepp

The search for potent antimicrobial compounds is critical in the face of growing antibiotic resistance. This study explores Acalypha arvensis Poepp. (A. arvensis), a Caribbean plant traditionally used for disease treatment. The dried plant powder was subjected to successive extractions using different solvents: hexane (F1), dichloromethane (F2), methanol (F3), a 50:50 mixture of methanol and water (F4), and water (F5). Additionally, a parallel extraction was conducted using a 50:50 mixture of methanol and chloroform (F6). All the fractions were evaluated for their antimicrobial activity, and the F6 fraction was characterized using untargeted metabolomics using SPME-GC×GC-TOFMS. The extracts of A. arvensis F3, F4, and F5 showed antibacterial activity against Staphylococcus aureus ATCC 25923 (5 mg/mL), MRSA BA22038 (5 mg/mL), and Pseudomonas aeruginosa ATCC 27853 (10 mg/mL), and fraction F6 showed antibacterial activity against Staphylococcus aureus ATCC 29213 (2 mg/mL), Escherichia coli ATCC 25922 (20 mg/mL), Pseudomonas aeruginosa ATCC 27853 (10 mg/mL), Enterococcus faecalis ATCC 29212 (10 mg/mL), Staphylococcus aureus 024 (2 mg/mL), and Staphylococcus aureus 003 (2 mg/mL). Metabolomic analysis of F6 revealed 2861 peaks with 58 identified compounds through SPME and 3654 peaks with 29 identified compounds through derivatization. The compounds included methyl ester fatty acids, ethyl ester fatty acids, terpenes, ketones, sugars, amino acids, and fatty acids. This study represents the first exploration of A. arvensis metabolomics and its antimicrobial potential, providing valuable insights for plant classification, phytochemical research, and drug discovery.

Origin of Antibiotics and Antibiotic Resistance, and Their Impacts on Drug Development: A Narrative Review

Antibiotics have revolutionized medicine, saving countless lives since their discovery in the early 20th century. However, the origin of antibiotics is now overshadowed by the alarming rise in antibiotic resistance. This global crisis stems from the relentless adaptability of microorganisms, driven by misuse and overuse of antibiotics. This article explores the origin of antibiotics and the subsequent emergence of antibiotic resistance. It delves into the mechanisms employed by bacteria to develop resistance, highlighting the dire consequences of drug resistance, including compromised patient care, increased mortality rates, and escalating healthcare costs. The article elucidates the latest strategies against drug-resistant microorganisms, encompassing innovative approaches such as phage therapy, CRISPR-Cas9 technology, and the exploration of natural compounds. Moreover, it examines the profound impact of antibiotic resistance on drug development, rendering the pursuit of new antibiotics economically challenging. The limitations and challenges in developing novel antibiotics are discussed, along with hurdles in the regulatory process that hinder progress in this critical field. Proposals for modifying the regulatory process to facilitate antibiotic development are presented. The withdrawal of major pharmaceutical firms from antibiotic research is examined, along with potential strategies to re-engage their interest. The article also outlines initiatives to overcome economic challenges and incentivize antibiotic development, emphasizing international collaborations and partnerships. Finally, the article sheds light on government-led initiatives against antibiotic resistance, with a specific focus on the Middle East. It discusses the proactive measures taken by governments in the region, such as Saudi Arabia and the United Arab Emirates, to combat this global threat. In the face of antibiotic resistance, a multifaceted approach is imperative. This article provides valuable insights into the complex landscape of antibiotic development, regulatory challenges, and collaborative efforts required to ensure a future where antibiotics remain effective tools in safeguarding public health.

Novel photoactivated Indole-pyridine chemotherapeutics with strong antimicrobial and antibiofilm activity toward Staphylococcus aureus

The challenge of antibiotic resistance worldwide has brought an urgent need to explore novel drugs for bacterial infections. Antimicrobial photodynamic therapy has been proven to be a potential antimicrobial modality but is limited by biofilms. In this study, we synthesized three cationic photosensitizers with strong photoinduced antimicrobial and antibiofilm activities toward gram-positive Staphylococcus aureus. The indole-pyridine compounds illustrated multiple type I/II photosensitization and coenzyme NAD(P)H photocatalytic activity upon excitation. A mechanistic study showed that intracellular reactive oxygen generation and NAD(P)H oxidation caused membrane damage, leading to protein/nucleus acid leakage. This research provides insights into the development of novel chemotherapeutics with synergetic photodynamic and photocatalytic reactivity.

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.

Development and Research Progress of Anti-Drug Resistant Bacteria Drugs

Bacterial resistance has become increasingly serious because of the widespread use and abuse of antibiotics. In particular, the emergence of multidrug-resistant bacteria has posed a serious threat to human public health and attracted the attention of the World Health Organization (WHO) and the governments of various countries. Therefore, the establishment of measures against bacterial resistance and the discovery of new antibacterial drugs are increasingly urgent to better contain the emergence of bacterial resistance and provide a reference for the development of new antibacterial drugs. In this review, we discuss some antibiotic drugs that have been approved for clinical use and a partial summary of the meaningful research results of anti-drug resistant bacterial drugs in different fields, including the antibiotic drugs approved by the FDA from 2015 to 2020, the potential drugs against drug-resistant bacteria, the new molecules synthesized by chemical modification, combination therapy, drug repurposing, immunotherapy and other therapies.

New insights into the structure and function of an emerging drug target CysE

The antimicrobial resistant strains of several pathogens are major culprits of hospital-acquired nosocomial infections. An active and urgent action is necessary against these pathogens for the development of unique therapeutics. The cysteine biosynthetic pathway or genes (that are absent in humans) involved in the production of L-cysteine appear to be an attractive target for developing novel antibiotics. CysE, a Serine Acetyltransferase (SAT), catalyzes the first step of cysteine synthesis and is reported to be essential for the survival of persistence in several microbes including Mycobacterium tuberculosis. Structure determination provides fundamental insight into structure and function of protein and aid in drug design/discovery efforts. This review focuses on the overview of current knowledge of structure function, regulatory mechanism, and potential inhibitors (active site as well as allosteric site) of CysE. Despite having conserved structure, slight modification in CysE structure lead to altered the regulatory mechanism and hence affects the cysteine production. Due to its possible role in virulence and vital metabolism of pathogens makes it a potential target in the quest to develop novel therapeutics to treat multi-drug-resistant bacteria.

The Functional Significance of Hydrophobic Residue Distribution in Bacterial Beta-Barrel Transmembrane Proteins

β-barrel membrane proteins have several important biological functions, including transporting water and solutes across the membrane. They are active in the highly hydrophobic environment of the lipid membrane, as opposed to soluble proteins, which function in a more polar, aqueous environment. Globular soluble proteins typically have a hydrophobic core and a polar surface that interacts favorably with water. In the fuzzy oil drop (FOD) model, this distribution is represented by the 3D Gauss function (3DG). In contrast, membrane proteins expose hydrophobic residues on the surface, and, in the case of ion channels, the polar residues face inwards towards a central pore. The distribution of hydrophobic residues in membrane proteins can be characterized by means of 1–3DG, a complementary 3D Gauss function. Such an analysis was carried out on the transmembrane proteins of bacteria, which, despite the considerable similarities of their super-secondary structure (β-barrel), have highly differentiated properties in terms of stabilization based on hydrophobic interactions. The biological activity and substrate specificity of these proteins are determined by the distribution of the polar and nonpolar amino acids. The present analysis allowed us to compare the ways in which the different proteins interact with antibiotics and helped us understand their relative importance in the development of the resistance mechanism. We showed that beta barrel membrane proteins with a hydrophobic core interact less strongly with the molecules they transport.

Antimicrobial innovation: a current update and perspective on the antibiotic drug development pipeline

As bacteria continue to develop resistance to our existing treatment options, antibiotic innovation remains overlooked. If current trends continue, then we could face the stark reality of a postantibiotic era, whereby routine bacterial infections could once again become deadly. In light of a warning signaled by the WHO, a number of new initiatives have been established in the hope of reinvigorating the antibiotic drug development pipeline. In this perspective, we aim to summarize some of these initiatives and funding options, as well as providing an insight into the predicament that we face. Using clinical trials data, company website information and the most recent press releases, a current update of the antibiotic drug development pipeline is also included.

Polypharmacological drug actions of recently FDA approved antibiotics

The current epidemic of antibiotic resistant bacterial infections has fueled the demand for novel antibiotics exhibiting both antibacterial efficacy and anti-drug resistance. This need has not been fully satisfied by the conventional "one target-one molecule" approach. Consequently, there has been rising interest in the development of multi-target antibiotics. Over the past two decades, 52% (14 out of 27) of the FDA approved antibiotics have demonstrated synergistic, multi-target mechanisms of action. Among these are three second-generation lipoglycopeptides, five new generation quinolones and six modernized β-lactams. This review focuses on the structure-activity relationship (SAR) analysis and the polypharmacological drug action of these antibiotics, to reveal how these multi-target antibiotics achieve the dual objectives of maximizing bactericidal or bacteriostatic efficacy and minimizing antibiotic resistance. The entrance of multi-target antibiotics into the FDA-approved regimens represents a milestone in the evolution of drug discovery as it has transcended from chemical library screening to rational drug design.

Metal-Based Nanoparticles as Antimicrobial Agents: An Overview

Metal-based nanoparticles have been extensively investigated for a set of biomedical applications. According to the World Health Organization, in addition to their reduced size and selectivity for bacteria, metal-based nanoparticles have also proved to be effective against pathogens listed as a priority. Metal-based nanoparticles are known to have non-specific bacterial toxicity mechanisms (they do not bind to a specific receptor in the bacterial cell) which not only makes the development of resistance by bacteria difficult, but also broadens the spectrum of antibacterial activity. As a result, a large majority of metal-based nanoparticles efficacy studies performed so far have shown promising results in both Gram-positive and Gram-negative bacteria. The aim of this review has been a comprehensive discussion of the state of the art on the use of the most relevant types of metal nanoparticles employed as antimicrobial agents. A special emphasis to silver nanoparticles is given, while others (e.g., gold, zinc oxide, copper, and copper oxide nanoparticles) commonly used in antibiotherapy are also reviewed. The novelty of this review relies on the comparative discussion of the different types of metal nanoparticles, their production methods, physicochemical characterization, and pharmacokinetics together with the toxicological risk encountered with the use of different types of nanoparticles as antimicrobial agents. Their added-value in the development of alternative, more effective antibiotics against multi-resistant Gram-negative bacteria has been highlighted.

Cost Drivers of a Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia Phase 3 Clinical Trial

Background

Studies indicate that the prevalence of multidrug-resistant infections, including hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP), has been rising. There are many challenges associated with these disease conditions and the ability to develop new treatments. Additionally, HABP/VABP clinical trials are very costly to conduct given their complex protocol designs and the difficulty in recruiting and retaining patients.

Methods

With input from clinicians, representatives from industry, and the US Food and Drug Administration, we conducted a study to (1) evaluate the drivers of HABP/VABP phase 3 direct and indirect clinical trial costs; (2) to identify opportunities to lower these costs; and (3) to compare (1) and (2) to endocrine and oncology clinical trials. Benchmark data were gathered from proprietary and commercial databases and used to create a model that calculates the fully loaded (direct and indirect) cost of typical phase 3 HABP/VABP endocrine and oncology clinical trials.

Results

Results indicate that the cost per patient for a 200-site, 1000-patient phase 3 HABP/VABP study is $89600 per patient. The cost of screen failures and screen failure rates are the main cost drivers.

Conclusions

Results indicate that biopharmaceutical companies and regulatory agencies should consider strategies to improve screening and recruitment to decrease HABP/VABP clinical trial costs.

Resisting resistance: gearing up for war

Where do we stand in our fight against antimicrobial resistance (AMR)? Many antimicrobials may lose their clinical efficacy, particularly due to the rise of multidrug-resistant (MDR) and extended drug-resistant (XDR) pathogens, including bacteria, fungi, and parasites. We need weapons against them all. Society must come together against these pathogens, just like we did against HIV, cancer, and heart disease. This opinion piece is, first and foremost, a call to arms for all partners involved in the war against AMR. Even more so, it is an attempt to highlight the positives in a seemingly long line of failures, and to identify the current set of challenges we must work on. So, how do we win the war against AMR? We must learn from the past, so we can act in the present, to save the future.

A High-Throughput Screening Approach To Repurpose FDA-Approved Drugs for Bactericidal Applications against Staphylococcus aureus Small-Colony Variants

Conventional antibiotics fail to successfully treat chronic osteomyelitis, endocarditis, and device-related and airway infections. These recurring infections are associated with the emergence of SCV, which are recalcitrant to conventional antibiotics. Studies have investigated antibiotic therapies to treat SCV-related infections but have had little success, emphasizing the need to identify novel antimicrobial drugs. However, drug discovery is a costly and time-consuming process. An alternative strategy is drug repurposing, which could identify FDA-approved and well-characterized drugs that could have off-label utility in treating SCV. In this study, we adapted a high-throughput AK-based assay to identify 4 FDA-approved drugs, daunorubicin, ketoconazole, rifapentine, and sitafloxacin, which display antimicrobial activity against S. aureus SCV, suggesting an avenue for drug repurposing in order to effectively treat SCV-related infections. Additionally, this screening paradigm can easily be adapted for other drug/chemical libraries to identify compounds bactericidal against SCV.

Drug repurposing offers an expedited and economical route to develop new clinical therapeutics in comparison to traditional drug development. Growth-based high-throughput screening is concomitant with drug repurposing and enables rapid identification of new therapeutic uses for investigated drugs; however, this traditional method is not compatible with microorganisms with abnormal growth patterns such as Staphylococcus aureus small-colony variants (SCV). SCV subpopulations are auxotrophic for key compounds in biosynthetic pathways, which result in low growth rate. SCV formation is also associated with reduced antibiotic susceptibility, and the SCV’s ability to revert to the normal cell growth state is thought to contribute to recurrence of S. aureus infections. Thus, there is a critical need to identify antimicrobial agents that are potent against SCV in order to effectively treat chronic infections. Accordingly, here we describe adapting an adenylate kinase (AK)-based cell death reporter assay to identify members of a Food and Drug Administration (FDA)-approved drug library that display bactericidal activity against S. aureus SCV. Four library members, daunorubicin, ketoconazole, rifapentine, and sitafloxacin, exhibited potent SCV bactericidal activity against a stable S. aureus SCV. Further investigation showed that sitafloxacin was potent against methicillin-susceptible and -resistant S. aureus, as well as S. aureus within an established biofilm. Taken together, these results demonstrate the ability to use the AK assay to screen small-molecule libraries for SCV bactericidal agents and highlight the therapeutic potential of sitafloxacin to be repurposed to treat chronic S. aureus infections associated with SCV and/or biofilm growth states.

IMPORTANCE Conventional antibiotics fail to successfully treat chronic osteomyelitis, endocarditis, and device-related and airway infections. These recurring infections are associated with the emergence of SCV, which are recalcitrant to conventional antibiotics. Studies have investigated antibiotic therapies to treat SCV-related infections but have had little success, emphasizing the need to identify novel antimicrobial drugs. However, drug discovery is a costly and time-consuming process. An alternative strategy is drug repurposing, which could identify FDA-approved and well-characterized drugs that could have off-label utility in treating SCV. In this study, we adapted a high-throughput AK-based assay to identify 4 FDA-approved drugs, daunorubicin, ketoconazole, rifapentine, and sitafloxacin, which display antimicrobial activity against S. aureus SCV, suggesting an avenue for drug repurposing in order to effectively treat SCV-related infections. Additionally, this screening paradigm can easily be adapted for other drug/chemical libraries to identify compounds bactericidal against SCV.

Quantitative and synthetic biology approaches to combat bacterial pathogens

Antibiotic resistance is one of the biggest threats to public health. The rapid emergence of resistant bacterial pathogens endangers the efficacy of current antibiotics and has led to increasing mortality and economic burden. This crisis calls for more rapid and accurate diagnosis to detect and identify pathogens, as well as to characterize their response to antibiotics. Building on this foundation, treatment options also need to be improved to use current antibiotics more effectively and develop alternative strategies that complement the use of antibiotics. We here review recent developments in diagnosis and treatment of bacterial pathogens with a focus on quantitative biology and synthetic biology approaches.

Diversity and Proliferation of Metallo-β-Lactamases: a Clarion Call for Clinically Effective Metallo-β-Lactamase Inhibitors

The worldwide proliferation of life-threatening metallo-β-lactamase (MBL)-producing Gram-negative bacteria is a serious concern to public health. MBLs are compromising the therapeutic efficacies of β-lactams, particularly carbapenems, which are last-resort antibiotics indicated for various multidrug-resistant bacterial infections. Inhibition of enzymes mediating antibiotic resistance in bacteria is one of the major promising means for overcoming bacterial resistance. Compounds having potential MBL-inhibitory activity have been reported, but none are currently under clinical trials. The need for developing safe and efficient MBL inhibitors (MBLIs) is obvious, particularly with the continuous spread of MBLs worldwide. In this review, the emergence and escalation of MBLs in Gram-negative bacteria are discussed. The relationships between different class B β-lactamases identified up to 2017 are represented by a phylogenetic tree and summarized. In addition, approved and/or clinical-phase serine β-lactamase inhibitors are recapitulated to reflect the successful advances made in developing class A β-lactamase inhibitors. Reported MBLIs, their inhibitory properties, and their purported modes of inhibition are delineated. Insights into structural variations of MBLs and the challenges involved in developing potent MBLIs are also elucidated and discussed. Currently, natural products and MBL-resistant β-lactam analogues are the most promising agents that can become clinically efficient MBLIs. A deeper comprehension of the mechanisms of action and activity spectra of the various MBLs and their inhibitors will serve as a bedrock for further investigations that can result in clinically useful MBLIs to curb this global menace.

Enzyme targets for drug design of new anti-virulence therapeutics

Society has benefitted greatly from the use of antibiotics. Unfortunately, the misuse of these valuable molecules has resulted in increased levels of antibiotic resistance, a major global and public health issue. This resistance and the reliance on a small number of biological targets for the development of antibiotics emphasizes the need for new targets. A critical aspect guiding the development of new antimicrobials through a rational structure-guided approach is to understand the molecular structures of specific biological targets of interest. Here we give an overview of the structures of bacterial virulence enzyme targets involved in protein folding, peptidoglycan biosynthesis and cell wall modification. These include enzymes of the thiol-disulphide oxidoreductase pathway (DSB enzymes), peptidyl-proly cis/trans isomerases (Mips), enzymes from the Mur pathway and enzymes involved in lipopolysaccharide modification (EptA and ArnT). We also present progress towards inhibitor design of these targets for the development of novel anti-virulence therapeutic agents.

Humanome Versus Microbiome: Games of Dominance and Pan-Biosurveillance in the Omics Universe

Global governance of pathogens such as Ebola virus and infectious diseases is central to global health, and to innovation in systems medicine. Worrisomely, the gaps in human immunity and healthcare services combined with novel pathogens emerging by travel, biotechnological advances, or the rupture of the host-species barrier challenge infectious diseases' global governance. Such biorisks and biothreats may scale up to global catastrophic biological risks (GCBRs) spatiotemporally, either as individual or as collective risks. The scale and intensity of such threats challenge current thinking on surveillance, and calls for a move toward pan-biosurveillance. New multilayered, cross-sectoral, and adaptable strategies of prevention and intervention on GCBRs should be developed, considering human hosts in entirety, and in close relationship with other hosts (plants and animals). This also calls for the "Humanome," which we introduce in this study as the totality of human subjects plus any directly dependent biological or nonbiological entities (products, constructs, and interventions). Surveillance networks should be implemented by integrating communications, diagnostics, and robotics/aeronautics technologies. Suppression of pathogens must be enforced both before and during an epidemic outbreak, the former allowing more drastic measures before the pathogens harbor the host. We propose in this expert review that microbiome-level intervention might particularly prove as an effective solution in medical and environmental scales against traditional, currently emerging, and future infectious threats. We conclude with a discussion on the ways in which the humanome and microbiome contest and cooperate, and how this knowledge might usefully inform in addressing the GCBRs, bioterrorism, and associated threats in the pursuit of pan-biosurveillance.

A Grant Framework as a Push Incentive to Stimulate Research and Development of New Antibiotics

Antibiotic research and development (R&D) has failed to produce innovative antibiotics in the past two decades, which is due to both scientific and economic factors. We reviewed national and international funding agencies and critically assessed current grant funding mechanisms. Finally, we propose four complementary grant-funding incentives aimed to help developers along the R&D pipeline. Equally important objective of these incentives is to address some of the known R&D risks and bottlenecks.

Application of Nanoparticle Technologies in the Combat against Anti-Microbial Resistance

Anti-microbial resistance is a growing problem that has impacted the world and brought about the beginning of the end for the old generation of antibiotics. Increasingly, more antibiotics are being prescribed unnecessarily and this reckless practice has resulted in increased resistance towards these drugs, rendering them useless against infection. Nanotechnology presents a potential answer to anti-microbial resistance, which could stimulate innovation and create a new generation of antibiotic treatments for future medicines. Preserving existing antibiotic activity through novel formulation into or onto nanotechnologies can increase clinical longevity of action against infection. Additionally, the unique physiochemical properties of nanoparticles can provide new anti-bacterial modes of action which can also be explored. Simply concentrating on antibiotic prescribing habits will not resolve the issue but rather mitigate it. Thus, new scientific approaches through the development of novel antibiotics and formulations is required in order to employ a new generation of therapies to combat anti-microbial resistance.

Drug repurposing screens and synergistic drug-combinations for infectious diseases

Infectious diseases account for nearly one fifth of the worldwide death toll every year. The continuous increase of drug-resistant pathogens is a big challenge for treatment of infectious diseases. In addition, outbreaks of infections and new pathogens are potential threats to public health. Lack of effective treatments for drug-resistant bacteria and recent outbreaks of Ebola and Zika viral infections have become a global public health concern. The number of newly approved antibiotics has decreased significantly in the last two decades compared with previous decades. In parallel with this, is an increase in the number of drug-resistant bacteria. For these threats and challenges to be countered, new strategies and technology platforms are critically needed. Drug repurposing has emerged as an alternative approach for rapid identification of effective therapeutics to treat the infectious diseases. For treatment of severe infections, synergistic drug combinations using approved drugs identified from drug repurposing screens is a useful option which may overcome the problem of weak activity of individual drugs. Collaborative efforts including government, academic researchers and private drug industry can facilitate the translational research to produce more effective new therapeutic agents such as narrow spectrum antibiotics against drug-resistant bacteria for these global challenges.

LINKED ARTICLES

This article is part of a themed section on Inventing New Therapies Without Reinventing the Wheel: The Power of Drug Repurposing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.2/issuetoc.

Moral Polemics of Far-Reaching Economic Consequences of Antibiotics Overuse

The unethical overuse of antibiotics to seek to achieve a shortening of the treatment period raises the cost of health services and poses a threat to humanity due to the gradual development of antibiotic resistance. Other consequences of our modern passion for antibiotics have appeared. Small concentrations of antibiotic residues in sewage waters slow down the metabolism of anaerobic microorganism thereby reducing the overall performance of the anaerobic fermentation used to detoxify and digest sewage and other collected organic wastes. Reduced biogas yields represents a serious threat to the energy self-sufficiency of some waste-water treatment plants, so it might change them from energy producers into energy consumers. Morally justifiable production of renewable energy from bio-waste is also threatened by antibiotic residues that remain in the bio-waste.

Research and development of antibiotics: insights from patents and citation network

INTRODUCTION

Bacterial resistance to antibiotics develops at an alarming rate and leads to the increasing morbidity and health-care costs in recent years. However, the global research and development (R&D) of antibiotics has fallen behind the emergence and spread of bacterial resistance and the world is heading towards a 'post-antibiotic era'. In this context, systematic understanding of the technology landscape and evolving process of antibiotic R&D may help to provide insights for discovering future antibiotics more rationally.

AREAS COVERED

Patents and patent citations are broadly believed to be powerful tools in representing the technology advances and capturing technology flows. In all, 707 U.S. patents related to antibiotic R&D are collected and analyzed. Furthermore, patent citations are visualized by a network-based approach, while the inter-relationship between patented technologies on antibiotics is further revealed.

EXPERT OPINION

The current dry pipeline of antibiotic development requires substantial awareness and political support. It is essential to build an attractive and supportive environment for investment. Thus, a new antibiotic business model is needed to chase the balance between the market-oriented investment and public health goals. Additionally, drug development targeting Gram-negative bacteria, especially resistant Gram-negative bacteria, demands attentions from stakeholders because of their unmet medical needs.

Effectiveness of 5-Pyrrolidone-2-carboxylic Acid and Copper Sulfate Pentahydrate Association against Drug Resistant Staphylococcus Strains

Bacterial resistance is an ongoing challenge for pharmacotherapy and pharmaceutical chemistry. Staphylococcus aureus is the bacterial species which makes it most difficult to treat skin and soft tissue infections and it is seen in thousands of hospitalization cases each year. Severe but often underrated infectious diseases, such as complicated nasal infections, are primarily caused by MRSA and S. epidermidis too. With the aim of studying new drugs with antimicrobial activity and effectiveness on drug resistant Staphylococcus strains, our attention in this study was drawn on the activity of a new association between two natural products: 5-pyrrolidone-2-carboxylic acid (PCA), naturally produced by certain Lactobacillus species, and copper sulfate pentahydrate (CS). The antimicrobial susceptibility test was conducted taking into account 12 different Staphylococcus strains, comprising 6 clinical isolates and 6 resistant strains. PCA 4%, w/w, and CS 0.002%, w/w, association in distilled water solution was found to have bactericidal activity against all tested strains. Antimicrobial kinetics highlighted that PCA 4%, w/w, and CS 0.002% association could reduce by 5 log10 viable bacterial counts of MRSA and oxacillin resistant S. epidermidis in less than 5 and 3 minutes respectively. Microscopic investigations suggest a cell wall targeting mechanism of action. Being very safe and highly tolerated, the natural product PCA and CS association proved to be a promising antimicrobial agent to treat Staphylococcus related infections.

The 10 largest public and philanthropic funders of health research in the world: what they fund and how they distribute their funds

BACKGROUND

Little is known about who the main public and philanthropic funders of health research are globally, what they fund and how they decide what gets funded. This study aims to identify the 10 largest public and philanthropic health research funding organizations in the world, to report on what they fund, and on how they distribute their funds.

METHODS

The world's key health research funding organizations were identified through a search strategy aimed at identifying different types of funding organizations. Organizations were ranked by their reported total annual health research expenditures. For the 10 largest funding organizations, data were collected on (1) funding amounts allocated towards 20 health areas, and (2) schemes employed for distributing funding (intramural/extramural, project/'people'/organizational and targeted/untargeted funding). Data collection consisted of a review of reports and websites and interviews with representatives of funding organizations. Data collection was challenging; data were often not reported or reported using different classification systems.

RESULTS

Overall, 55 key health research funding organizations were identified. The 10 largest funding organizations together funded research for $37.1 billion, constituting 40% of all public and philanthropic health research spending globally. The largest funder was the United States National Institutes of Health ($26.1 billion), followed by the European Commission ($3.7 billion), and the United Kingdom Medical Research Council ($1.3 billion). The largest philanthropic funder was the Wellcome Trust ($909.1 million), the largest funder of health research through official development assistance was USAID ($186.4 million), and the largest multilateral funder was the World Health Organization ($135.0 million). Funding distribution mechanisms and funding patterns varied substantially between the 10 largest funders.

CONCLUSIONS

There is a need for increased transparency about who the main funders of health research are globally, what they fund and how they decide on what gets funded, and for improving the evidence base for various funding models. Data on organizations' funding patterns and funding distribution mechanisms are often not available, and when they are, they are reported using different classification systems. To start increasing transparency in health research funding, we have established www.healthresearchfunders.org that lists health research funding organizations worldwide and their health research expenditures.

A systematic review and critical assessment of incentive strategies for discovery and development of novel antibiotics

Despite the growing threat of antimicrobial resistance, pharmaceutical and biotechnology firms are reluctant to develop novel antibiotics because of a host of market failures. This problem is complicated by public health goals that demand antibiotic conservation and equitable patient access. Thus, an innovative incentive strategy is needed to encourage sustainable investment in antibiotics. This systematic review consolidates, classifies and critically assesses a total of 47 proposed incentives. Given the large number of possible strategies, a decision framework is presented to assist with the selection of incentives. This framework focuses on addressing market failures that result in limited investment, public health priorities regarding antibiotic stewardship and patient access, and implementation constraints and operational realities. The flexible nature of this framework allows policy makers to tailor an antibiotic incentive package that suits a country's health system structure and needs.

Applying the emergency risk management process to tackle the crisis of antibiotic resistance

We advocate that antibiotic resistance be reframed as a disaster risk management problem. Antibiotic-resistant infections represent a risk to life as significant as other commonly occurring natural disasters (e.g., earthquakes). Despite efforts by global health authorities, antibiotic resistance continues to escalate. Therefore, new approaches and expertise are needed to manage the issue. In this perspective we: (1) make a call for the emergency management community to recognize the antibiotic resistance risk and join in addressing this problem; (2) suggest using the risk management process to help tackle antibiotic resistance; (3) show why this approach has value and why it is different to existing approaches; and (4) identify public perception of antibiotic resistance as an important issue that warrants exploration.

Antibiotics and bacterial resistance in the 21st century

Dangerous, antibiotic resistant bacteria have been observed with increasing frequency over the past several decades. In this review the factors that have been linked to this phenomenon are addressed. Profiles of bacterial species that are deemed to be particularly concerning at the present time are illustrated. Factors including economic impact, intrinsic and acquired drug resistance, morbidity and mortality rates, and means of infection are taken into account. Synchronously with the waxing of bacterial resistance there has been waning antibiotic development. The approaches that scientists are employing in the pursuit of new antibacterial agents are briefly described. The standings of established antibiotic classes as well as potentially emerging classes are assessed with an emphasis on molecules that have been clinically approved or are in advanced stages of development. Historical perspectives, mechanisms of action and resistance, spectrum of activity, and preeminent members of each class are discussed.

The mismatch between the health research and development (R&D) that is needed and the R&D that is undertaken: an overview of the problem, the causes, and solutions

One of the most pressing global health problems is that there is a mismatch between the health research and development (R&D) that is needed and that which is undertaken. The dependence of health R&D on market incentives in the for-profit private sector and the lack of coordination by public and philanthropic funders on global R&D priorities have resulted in a global health R&D landscape that neglects certain products and populations and is characterised, more generally, by a distribution that is not 'needs-driven'. This article provides an overview of the mismatch, its causes, and solutions.

Targeting iron assimilation to develop new antibacterials

INTRODUCTION

Since the first application of antibiotics to treat bacterial infections, the development and spread of resistance has been a persistent threat. An ever evolving pipeline of next-generation therapeutics is required for modern medicine to remain one step ahead of pathogens.

AREAS COVERED

This review describes recent efforts to develop drugs that interrupt the assimilation of iron by bacteria: a process that is vital to cellular homeostasis and is not currently targeted by antibiotics used in the clinic. This review also covers the mechanisms by which bacteria acquire iron for their environment, and details efforts to intervene in these processes, using small molecule inhibitors that target key steps in these pathways, with a special emphasis on recent advances published during the 2010 - 2012 period.

EXPERT OPINION

For decades, the routes used by bacteria to assimilate iron from host and environmental settings have been the subject of intense study. While numerous investigations have identified inhibitors of these pathways, many have stopped short of translating the in vitro results to in vivo proof of concept experiments. The extension of preliminary findings in this manner will significantly increase the impact of the field.

Ready for a world without antibiotics? The Pensières Antibiotic Resistance Call to Action

Resistance to antibiotics has increased dramatically over the past few years and has now reached a level that places future patients in real danger. Microorganisms such as Escherichia coli and Klebsiella pneumoniae, which are commensals and pathogens for humans and animals, have become increasingly resistant to third-generation cephalosporins. Moreover, in certain countries, they are also resistant to carbapenems and therefore susceptible only to tigecycline and colistin. Resistance is primarily attributed to the production of beta-lactamase genes located on mobile genetic elements, which facilitate their transfer between different species. In some rare cases, Gram-negative rods are resistant to virtually all known antibiotics. The causes are numerous, but the role of the overuse of antibiotics in both humans and animals is essential, as well as the transmission of these bacteria in both the hospital and the community, notably via the food chain, contaminated hands, and between animals and humans. In addition, there are very few new antibiotics in the pipeline, particularly for Gram-negative bacilli. The situation is slightly better for Gram-positive cocci as some potent and novel antibiotics have been made available in recent years. A strong and coordinated international programme is urgently needed. To meet this challenge, 70 internationally recognized experts met for a two-day meeting in June 2011 in Annecy (France) and endorsed a global call to action ("The Pensières Antibiotic Resistance Call to Action"). Bundles of measures that must be implemented simultaneously and worldwide are presented in this document. In particular, antibiotics, which represent a treasure for humanity, must be protected and considered as a special class of drugs.

[Programs for optimizing the use of antibiotics (PROA) in Spanish hospitals: GEIH-SEIMC, SEFH and SEMPSPH consensus document]

The antimicrobial agents are unique drugs for several reasons. First, their efficacy is higher than other drugs in terms of reduction of morbidity and mortality. Also, antibiotics are the only group of drugs associated with ecological effects, because their administration may contribute to the emergence and spread of microbial resistance. Finally, they are used by almost all medical specialties. Appropriate use of antimicrobials is very complex because of the important advances in the management of infectious diseases and the spread of antibiotic resistance. Thus, the implementation of programs for optimizing the use of antibiotics in hospitals (called PROA in this document) is necessary. This consensus document defines the objectives of the PROA (namely, to improve the clinical results of patients with infections, to minimise the adverse events associated to the use of antimicrobials including the emergence and spread of antibiotic resistance, and to ensure the use of the most cost-efficacious treatments), and provides recommendations for the implementation of these programs in Spanish hospitals. The key aspects of the recommendations are as follows. Multidisciplinary antibiotic teams should be formed, under the auspices of the Infection Committees. The PROA need to be considered as part of institutional programs and the strategic objectives of the hospital. The PROA should include specific objectives based on measurable indicators, and activities aimed at improving the use of antimicrobials, mainly through educational activities and interventions based more on training activities directed to prescribers than just on restrictive measures.

Insect natural products and processes: new treatments for human disease

In this overview, some of the more significant recent developments in bioengineering natural products from insects with use or potential use in modern medicine are described, as well as in utilisation of insects as models for studying essential mammalian processes such as immune responses to pathogens. To date, insects have been relatively neglected as sources of modern drugs although they have provided valuable natural products, including honey and silk, for at least 4-7000 years, and have featured in folklore medicine for thousands of years. Particular examples of Insect Folk Medicines will briefly be described which have subsequently led through the application of molecular and bioengineering techniques to the development of bioactive compounds with great potential as pharmaceuticals in modern medicine. Insect products reviewed have been derived from honey, venom, silk, cantharidin, whole insect extracts, maggots, and blood-sucking arthropods. Drug activities detected include powerful antimicrobials against antibiotic-resistant bacteria and HIV, as well as anti-cancer, anti-angiogenesis and anti-coagulant factors and wound healing agents. Finally, the many problems in developing these insect products as human therapeutic drugs are considered and the possible solutions emerging to these problems are described.

Risk-benefit analysis of restricting antimicrobial prescribing in children: what do we really know?

PURPOSE OF REVIEW

Most childhood respiratory infections including acute otitis media (AOM), sore throat, upper respiratory tract infections (URTIs) and sinusitis are self-limiting illnesses. Yet, despite extensive guidance discouraging routine use of antibiotics to limit side-effects and combat antimicrobial resistance, antibiotic prescribing for these conditions remains high in many developed countries, fuelled by the fear of rare but serious bacterial complications including mastoiditis, quinsy, pneumonia and brain abscess. This review summarizes evidence for the role of antibiotics in preventing serious complications of URTIs in children.

RECENT FINDINGS

From a key observational study reporting antibiotic use in children, the calculated excess risk of suppurative complications of respiratory tract infections in children who did not receive an antibiotic was 3.8 per 10 000. Despite extensive searches of the literature, no data were found to assess the affect of antibiotics upon the risk of brain abscess after sinusitis in children.

SUMMARY

New information from observational studies suggests antibiotics show little benefit in preventing complications of mastoiditis following AOM, quinsy following sore throat and pneumonia following URTI/bronchitis. Further research should focus on stratifying the key risk factors for such complications and optimizing long-term monitoring strategies to detect any future changes in the risk-benefit analysis for antibiotic prescription.

Novel Inhibitors of E. coli RecA ATPase Activity

The bacterial RecA protein has been implicated as a bacterial drug target not as an antimicrobial target, but as an adjuvant target with the potential to suppress the mechanism by which bacteria gain drug resistance. In order to identify small molecules that inhibit RecA/ssDNA nucleoprotein filament formation, we have adapted the phosphomolybdate-blue ATPase assay for high throughput screening to determine RecA ATPase activity against a library of 33,600 compounds, which is a selected representation of diverse structure of 350,000. Four distinct chemotypes were represented among the 40 validated hits. SAR and further chemical synthesis is underway to optimize this set of inhibitors to be used as antimicrobial adjuvant agents.

Save antibiotics. What can be done to prevent a forecasted disaster! Suggestions to promote the development of new antibiotics

New antibiotics are needed because of the increasing resistance of bacteria but they will be available in years to come only if drastic changes are implemented in development strategies, evaluation, use, and financing. Over the last decade, various opinions were stated and limited action was undertaken. Optimizing antibiotic use (as the "antibiotic plan" in France) was indispensable, but the process is still on going, and this is only part of the problem. Major questions are recurrently raised such as improvement of development procedures for new antibiotics, optimizing diagnostic methods, innovating financing modalities, or rescue of "old" antibiotics at risk of being withdrawn from the market. The symposium organized in September 2009 by the Swedish EU presidency helped to support previous recommendations. But conclusions remain unspecific. The propositions which are made here, after a work session, have for aim to be more detailed and innovating, even if they can be discussed, or even provocative.

Inhibitors of RecA activity discovered by high-throughput screening: cell-permeable small molecules attenuate the SOS response in Escherichia coli

The phenomenon of antibiotic resistance has created a need for the development of novel antibiotic classes with nonclassical cellular targets. Unfortunately, target-based drug discovery against proteins considered essential for in vitro bacterial viability has yielded few new therapeutic classes of antibiotics. Targeting the large proportion of genes considered nonessential that have yet to be explored by high-throughput screening, for example, RecA, can complement these efforts. Recent evidence suggests that RecA-controlled processes are responsible for tolerance to antibiotic chemotherapy and are involved in pathways that ultimately lead to full-fledged antibiotic resistance. Therefore inhibitors of RecA may serve as therapeutic adjuvants in combination chemotherapy of bacterial infectious diseases. Toward the goal of validating RecA as a novel target in the chemotherapy of bacterial infections, the authors have screened 35,780 small molecules against RecA. In total, 80 small molecules were identified as primary hits and could be clustered in 6 distinct chemotype clades. The most potent class of hits was further examined, and 1 member compound was found to inhibit RecA-mediated strand exchange and prevent ciprofloxacin-induced SOS expression in Escherichia coli. This compound represents the first small molecule demonstrating an ability to inhibit the bacterial SOS response in live bacterial cell cultures.