The introduction of 'chemotherapy' using arsphenamine - the first magic bullet

Antiprotozoal Pt(II) Complexes as Luminophores Bearing Monodentate P/As/Sb-Based Donors: An X-ray Diffractometric, Photoluminescence, and 121Sb-Mössbauer Spectroscopic Study with TD-DFT-Guided Interpretation and Predictive Extrapolation toward Bi

In this study, it is demonstrated that the radiative rate constant of phosphorescent metal complexes can be substantially enhanced using monodentate ancillary ligands containing heavy donor atoms. Thus, the chlorido coligand from a Pt(II) complex bearing a monoanionic tridentate C^N*N luminophore ([PtLCl]) was replaced by triphenylphosphane (PPh3) and its heavier pnictogen congeners (i.e., PnPh3 to yield [PtL(PnPh3)]). Due to the high tridentate-ligand-centered character of the excited states, the P-related radiative rate is rather low while showing a significant boost upon replacement of the P donor by heavier As- and Sb-based units. The syntheses of the three complexes containing PPh3, AsPh3, and SbPh3 were completed by unambiguous characterization of the clean products using exact mass spectrometry, X-ray diffractometry, bidimensional NMR, and 121Sb-Mössbauer spectroscopy (for [PtL(SbPh3)]) as well as steady state and time-resolved photoluminescence spectroscopies. Hence, it was shown that the hybridization defects of the Vth main-group atoms can be overcome by complexation with the Pt center. Notably, the enhancement of the radiative rate constants mediated by heavier coligands was achieved without significantly influencing the character of the excited states. A rationalization of the results was achieved by TD-DFT. Even though the Bi-based homologue was not accessible due to phenylation side reactions, the experimental data allowed a reasonable extrapolation of the structural features whereas the hybridization defects and the excited state properties related to the Bi-species and its phosphorescence rate can be predicted by theory. The three complexes showed an interesting antiprotozoal activity, which was unexpectedly notorious for the P-containing complex. This work could pave the road toward new efficient materials for optoelectronics and novel antiparasitic drugs.

Reinvent Aliphatic Arsenicals as Reversible Covalent Warheads toward Targeted Kinase Inhibition and Non-acute Promyelocytic Leukemia Cancer Treatment

The success of arsenic in acute promyelocytic leukemia (APL) treatment is hardly transferred to non-APL cancers, mainly due to the low selectivity and weak binding affinity of traditional arsenicals to oncoproteins critical for cancer survival. We present herein the reinvention of aliphatic trivalent arsenicals (As) as reversible covalent warheads of As-based targeting inhibitors toward Bruton's tyrosine kinase (BTK). The effects of As warheads' valency, thiol protection, methylation, spacer length, and size on inhibitors' activity were studied. We found that, in contrast to the bulky and rigid aromatic As warhead, the flexible aliphatic As warheads were well compatible with the well-optimized guiding group to achieve nanomolar inhibition against BTK. The optimized As inhibitors effectively blocked the BTK-mediated oncogenic signaling pathway, leading to elevated antiproliferative activities toward lymphoma cells and xenograft tumor. Our study provides a promising strategy enabling rational design of new aliphatic arsenic-based reversible covalent inhibitors toward non-APL cancer treatment.

Crystal structure of di-benzyl-ammonium hydrogen (4-amino-phen-yl)arsonate monohydrate

The title salt, C14H16N+·C6H7AsNO3 -·H2O or [(C6H5CH2)2NH2][H2NC6H4As(OH)O2]·H2O, (I), was synthesized by mixing an aqueous solution of (4-amino-phenyl)-arsonic acid with an ethano-lic solution of di-benzyl-amine at room temperature. Compound I crystallizes in the monoclinic P21/c space group. The three components forming I are linked via N-H⋯O and O-H⋯O inter-molecular hydrogen bonds, resulting in the propagation of an infinite zigzag chain. Additional weak inter-actions between neighbouring chains, such as π-π and N-H⋯O contacts, involving phenyl rings, -NH2 and -As(OH)O3 functions, and H2O, respectively, lead to a three-dimensional network.

Recent advances in fluorescence-based chemosensing of organoarsenic feed additives using luminescence MOFs, COFs, HOFs, and QDs

Organoarsenics are low-toxicity compounds that are used widely as feed additives to promote livestock growth, enhance meat pigmentation, and fight against intestinal parasites. The organoarsenic compounds are commonly found in poultry waste and the degradation of organoarsenic produces the toxic carcinogen inorganic arsenic such as As(V) and As(III), which results in severe arsenic pollution of soil and groundwater. As a consequence, there exists a high necessity to develop suitable sensing methods for the trace detection and quantification of organoarsenic feed additives in wastewater. Among various detection methods, in particular, fluorescence-based sensing has become a popular and efficient method used extensively for sensing water contaminants and environmental contaminants. In the recent past, a wide variety of fluorescence chemosensors have been designed and employed for the efficient sensing and quantification of the concentration of organoarsenic feed additives in different environmental samples. This review article systematically highlights various fluorescence chemosensors reported to date for fluorescence-based sensing of organoarsenic feed additives. The fluorescence sensors discussed in this review are classified and grouped according to their structures and functions, and in each section, we provide a detailed report on the structure, photophysics, and fluorescence sensing properties of different chemosensors. Lastly, the future perspectives on the design and development of practically useful sensor systems for selective and discriminative sensing of organoarsenic compounds have been stated.

Nanosilver: An Old Antibacterial Agent with Great Promise in the Fight against Antibiotic Resistance

Antibiotic resistance in bacteria is a major problem worldwide that costs 55 billion USD annually for extended hospitalization, resource utilization, and additional treatment expenditures in the United States. This review examines the roles and forms of silver (e.g., bulk Ag, silver salts (AgNO3), and colloidal Ag) from antiquity to the present, and its eventual incorporation as silver nanoparticles (AgNPs) in numerous antibacterial consumer products and biomedical applications. The AgNP fabrication methods, physicochemical properties, and antibacterial mechanisms in Gram-positive and Gram-negative bacterial models are covered. The emphasis is on the problematic ESKAPE pathogens and the antibiotic-resistant pathogens of the greatest human health concern according to the World Health Organization. This review delineates the differences between each bacterial model, the role of the physicochemical properties of AgNPs in the interaction with pathogens, and the subsequent damage of AgNPs and Ag+ released by AgNPs on structural cellular components. In closing, the processes of antibiotic resistance attainment and how novel AgNP-antibiotic conjugates may synergistically reduce the growth of antibiotic-resistant pathogens are presented in light of promising examples, where antibiotic efficacy alone is decreased.

Antimicrobial Resistance in the Global Health Network: Known Unknowns and Challenges for Efficient Responses in the 21st Century

Antimicrobial resistance (AMR) is one of the Global Health challenges of the 21st century. The inclusion of AMR on the global map parallels the scientific, technological, and organizational progress of the healthcare system and the socioeconomic changes of the last 100 years. Available knowledge about AMR has mostly come from large healthcare institutions in high-income countries and is scattered in studies across various fields, focused on patient safety (infectious diseases), transmission pathways and pathogen reservoirs (molecular epidemiology), the extent of the problem at a population level (public health), their management and cost (health economics), cultural issues (community psychology), and events associated with historical periods (history of science). However, there is little dialogue between the aspects that facilitate the development, spread, and evolution of AMR and various stakeholders (patients, clinicians, public health professionals, scientists, economic sectors, and funding agencies). This study consists of four complementary sections. The first reviews the socioeconomic factors that have contributed to building the current Global Healthcare system, the scientific framework in which AMR has traditionally been approached in such a system, and the novel scientific and organizational challenges of approaching AMR in the fourth globalization scenario. The second discusses the need to reframe AMR in the current public health and global health contexts. Given that the implementation of policies and guidelines are greatly influenced by AMR information from surveillance systems, in the third section, we review the unit of analysis ("the what" and "the who") and the indicators (the "operational units of surveillance") used in AMR and discuss the factors that affect the validity, reliability, and comparability of the information to be applied in various healthcare (primary, secondary, and tertiary), demographic, and economic contexts (local, regional, global, and inter-sectorial levels). Finally, we discuss the disparities and similarities between distinct stakeholders' objectives and the gaps and challenges of combatting AMR at various levels. In summary, this is a comprehensive but not exhaustive revision of the known unknowns about how to analyze the heterogeneities of hosts, microbes, and hospital patches, the role of surrounding ecosystems, and the challenges they represent for surveillance, antimicrobial stewardship, and infection control programs, which are the traditional cornerstones for controlling AMR in human health.

Realgar and arsenene nanomaterials as arsenic-based anticancer agents

Arsenic trioxide (ATO) is an approved therapy for the treatment of acute promyelocytic leukemia, but the extension of arsenic-based therapies to other types of malignancies, notably tumor-forming cancers, has been slow. Nanodelivery vehicles offer a means of effectively delivering ATO to tumors. Very recently, there has been a series of developments in the formulation of arsenic-based nanomedicines that are not simply loaded with ATO. Realgar nanoparticles are comprised of molecular As₄S₄ units. Current studies suggest that realgar nanoparticles ultimately act in a manner similar to ATO, but with greatly attenuated toxic side effects. A drastically different approach is taken with arsenene nanosheets, a 2-dimensional form of elemental As. The electronic properties of this material allow it to mediate both photothermal therapy and photodynamic therapy. The exploration of these nanomaterials is still in its infancy but is poised to allow arsenic-based therapy to make yet another significant impact on cancer treatment.

No more tears from surgical site infections in interventional pain management

As the field of interventional pain management (IPM) grows, the risk of surgical site infections (SSIs) is increasing. SSI is defined as an infection of the incision or organ/space that occurs within one month after operation or three months after implantation. It is also common to find patients with suspected infection in an outpatient clinic. The most frequent IPM procedures are performed in the spine. Even though primary pyogenic spondylodiscitis via hematogenous spread is the most common type among spinal infections, secondary spinal infections from direct inoculation should be monitored after IPM procedures. Various preventive guidelines for SSI have been published. Cefazolin, followed by vancomycin, is the most commonly used surgical antibiotic prophylaxis in IPM. Diagnosis of SSI is confirmed by purulent discharge, isolation of causative organisms, pain/tenderness, swelling, redness, or heat, or diagnosis by a surgeon or attending physician. Inflammatory markers include traditional (C-reactive protein, erythrocyte sedimentation rate, and white blood cell count) and novel (procalcitonin, serum amyloid A, and presepsin) markers. Empirical antibiotic therapy is defined as the initial administration of antibiotics within at least 24 hours prior to the results of blood culture and antibiotic susceptibility testing. Definitive antibiotic therapy is initiated based on the above culture and testing. Combination antibiotic therapy for multidrug-resistant Gram-negative bacteria infections appears to be superior to monotherapy in mortality with the risk of increasing antibiotic resistance rates. The never-ending war between bacterial resistance and new antibiotics is continuing. This article reviews prevention, diagnosis, and treatment of infection in pain medicine.

The large part German medicine has played in the development of experimental pharmacology in Japan

The history of hitherto existing pharmacology in Japan presented here is authored in commemoration of the 150th anniversary of Naunyn-Schmiedeberg's Archives of Pharmacology. After the publication of the new book of anatomy "Anatomische Tabellen" translated into Japanese in 1774, the foundation of understanding the medical science was gradually formed in Japan under seclusion policy, and, since the Meiji Restoration of 1868, the modernization of Japanese medicine was rapidly fostered on the basis of German medicine. Thus, the Japanese government officially adopted German medicine, and the philosophy and practice of German medical schools were incorporated. Most of the medical texts used in Japan were of German origins, often in Dutch translations, and many Japanese physicians and medical researchers studied abroad in Germany. The start of experimental pharmacology in Japan was also made up by Japanese disciples of Oswald Schmiedeberg, who was the one of founders of the Archives in 1873. Additionally, it was customary for professor candidates in charge of pharmacology in medical faculties in Japan to go to Germany and study pharmacology. Through such historical circumstances, the Japanese Pharmacology Society has been established to fulfill the responsibility for contributing internationally to world-class research achievements in the field of medical sciences by supplying numerous talented pharmacologists. During the course of the development of experimental pharmacology in Japan, the Archives has provided an excellent stage for many Japanese pharmacologists to publish their research outcomes to proliferate them internationally. Without German medicine influence, Japanese pharmacology would not have been what it is today.

Role of Efflux Pumps on Antimicrobial Resistance in Pseudomonas aeruginosa

Antimicrobial resistance is an old and silent pandemic. Resistant organisms emerge in parallel with new antibiotics, leading to a major global public health crisis over time. Antibiotic resistance may be due to different mechanisms and against different classes of drugs. These mechanisms are usually found in the same organism, giving rise to multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. One resistance mechanism that is closely associated with the emergence of MDR and XDR bacteria is the efflux of drugs since the same pump can transport different classes of drugs. In Gram-negative bacteria, efflux pumps are present in two configurations: a transmembrane protein anchored in the inner membrane and a complex formed by three proteins. The tripartite complex has a transmembrane protein present in the inner membrane, a periplasmic protein, and a porin associated with the outer membrane. In Pseudomonas aeruginosa, one of the main pathogens associated with respiratory tract infections, four main sets of efflux pumps have been associated with antibiotic resistance: MexAB-OprM, MexXY, MexCD-OprJ, and MexEF-OprN. In this review, the function, structure, and regulation of these efflux pumps in P. aeruginosa and their actions as resistance mechanisms are discussed. Finally, a brief discussion on the potential of efflux pumps in P. aeruginosa as a target for new drugs is presented.

The past, present, and future of chemotherapy with a focus on individualization of drug dosing

While there have been rapid advances in developing new and more targeted drugs to treat cancer, much less progress has been made in individualizing dosing. Even though the introduction of immunotherapies such as CAR T-cells and checkpoint inhibitors, as well as personalized therapies that target specific mutations, have transformed clinical treatment of cancers, chemotherapy remains a mainstay in oncology. Chemotherapies are typically dosed on either a body surface area (BSA) or weight basis, which fails to account for pharmacokinetic differences between patients. Drug absorption, distribution, metabolism, and excretion rates can vary between patients, resulting in considerable differences in exposure to the active drugs. These differences result in suboptimal dosing, which can reduce efficacy and increase side-effects. Therapeutic drug monitoring (TDM), genotype guided dosing, and chronomodulation have been developed to address this challenge; however, despite improving clinical outcomes, they are rarely implemented in clinical practice for chemotherapies. Thus, there is a need to develop interventions that allow for individualized drug dosing of chemotherapies, which can help maximize the number of patients that reach the most efficacious level of drug in the blood while mitigating the risks of underdosing or overdosing. In this review, we discuss the history of the development of chemotherapies, their mechanisms of action and how they are dosed. We discuss substantial intraindividual and interindividual variability in chemotherapy pharmacokinetics. We then propose potential engineering solutions that could enable individualized dosing of chemotherapies, such as closed-loop drug delivery systems and bioresponsive biomaterials.

The magic bullet: Niclosamide

The term 'magic bullet' is a scientific concept proposed by the German Nobel laureate Paul Ehrlich in 1907, describing a medicine that could specifically and efficiently target a disease without harming the body. Oncologists have been looking for a magic bullet for cancer therapy ever since. However, the current therapies for cancers-including chemotherapy, radiation therapy, hormone therapy, and targeted therapy-pose either pan-cytotoxicity or only single-target efficacy, precluding their ability to function as a magic bullet. Intriguingly, niclosamide, an FDA-approved drug for treating tapeworm infections with an excellent safety profile, displays broad anti-cancer activity in a variety of contexts. In particular, niclosamide inhibits multiple oncogenic pathways such as Wnt/β-catenin, Ras, Stat3, Notch, E2F-Myc, NF-κB, and mTOR and activates tumor suppressor signaling pathways such as p53, PP2A, and AMPK. Moreover, niclosamide potentially improves immunotherapy by modulating pathways such as PD-1/PDL-1. We recently discovered that niclosamide ethanolamine (NEN) reprograms cellular metabolism through its uncoupler function, consequently remodeling the cellular epigenetic landscape to promote differentiation. Inspired by the promising results from the pre-clinical studies, several clinical trials are ongoing to assess the therapeutic effect of niclosamide in cancer patients. This current review summarizes the functions, mechanism of action, and potential applications of niclosamide in cancer therapy as a magic bullet.

Direct Detection of Antibacterial-Producing Soil Isolates Utilizing a Novel High-Throughput Screening Assay

The ever-increasing global threat of common infections developing resistance to current therapeutics is rapidly accelerating the onset of a primitive post-antibiotic era in medicine. The prevention of further antimicrobial resistance development is unlikely due to the continued misuse of antibiotics, augmented by the lack of discovery of novel antibiotics. Screening large libraries of synthetic compounds have yet to offer effective replacements for current antibiotics. Due to historical successes, discovery from large and diverse natural sources and, more specifically, environmental bacteria, may still yield novel alternative antibiotics. However, the process of antibiotic discovery from natural sources is laborious and time-consuming as a result of outdated methodologies. Therefore, we have developed a simple and rapid preliminary screening assay to identify antibacterial-producing bacteria from natural sources. In brief, the assay utilizes the presence or absence of luminescence in bioluminescent reporter bacteria and test bacterium co-cultures in a 96-well plate format to determine the absence or presence of antibacterial compound production. Our assay, called the bioluminescent simultaneous antagonism (BSLA) assay, can accurately distinguish between known antibacterial-producing and non-producing test bacteria. The BSLA assay was validated by screening 264 unknown soil isolates which resulted in the identification of 10 antibacterial-producing isolates, effectively decreasing the pool of isolates for downstream analysis by 96%. By design, the assay is simple and requires only general laboratory equipment; however, we have shown that the assay can be scaled to automated high-throughput screening systems. Taken together, the BSLA assay allows for the rapid pre-screening of unknown bacterial isolates which, when coupled with innovative downstream dereplication and identification technologies, can effectively fast-track antimicrobial discovery.

Non-Antibiotic Antimony-Based Antimicrobials

A series of the eight novel organoantimony(V) cyanoximates of Sb(C₆H₅)₄L composition was synthesized using the high-yield heterogeneous metathesis reaction between solid AgL (or TlL) and Sb(C₆H₅)₄Br in CH₃CN at room temperature. Cyanoximes L were specially selected from a large group of 48 known compounds of this subclass of oximes on the basis of their water solubility and history of prior biological activity. The synthesized compounds are well soluble in organic solvents and were studied using a variety of conventional spectroscopic and physical methods. The crystal structures of all reported organometallic compounds were determined and revealed the formation of the distorted trigonal bipyramidal environment of the Sb atom and monodentate axial binding of acido-ligands via the O atom of the oxime group. The compounds are thermally stable in the solid state and in solution molecular compounds. For the first time, this specially designed series of organoantimony(V) compounds is investigated as potential non-antibiotic antimicrobial agents against three bacterial and two fungal human pathogens known for their increasing antimicrobial resistance. Bacterial pathogens included Gram-negative Escherichia coli and Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus. Fungal pathogens included Cryptococcus neoformans and Candida albicans. The cyanoximates alone showed no antimicrobial impact, and the incorporation of the SbPh₄ group enabled the antimicrobial effect. Overall, the new antimony compounds showed a strong potential as both broad- and narrow-spectrum antimicrobials against selected bacterial and fundal pathogens and provide insights for further synthetic modifications of the compounds to increase their activities.

Derivation of a Precise and Consistent Timeline for Antibiotic Development

Antibiotic resistance is a global health crisis. New classes of antibiotics that can treat drug-resistant infections are urgently needed. To communicate this message, researchers have used antibiotic development timelines, but these are often contradictory or imprecise. We conducted a systematic literature review to produce an antibiotic timeline that incorporates the dates of discovery, first use, and initial reports of the emergence of resistance for the 38 classes of clinically used antibiotics. From our timeline, we derive lessons for identifying new antibiotics that are less prone to resistance. These include a required focus on molecules that exhibit multiple modes of action, possess unusually long 'resistance windows', or those that engage cellular targets whose molecular architectures are at least in part decoupled from evolutionary pressures. Our analysis also further highlights the importance of safeguarding antibiotics as a mechanism for mitigating the development of resistance. We have made our data and sources freely available so that the research community can adapt them to their own needs.

Challenges and opportunities in the development of metal-based anticancer theranostic agents

Around 10 million fatalities were recorded worldwide in 2020 due to cancer and statistical projections estimate the number to increase by 60% in 2040. With such a substantial rise in the global cancer burden, the disease will continue to impose a huge socio-economic burden on society. Currently, the most widely used clinical treatment modality is cytotoxic chemotherapy using platinum drugs which is used to treat variety of cancers. Despite its clinical success, critical challenges like resistance, off-target side effects and cancer variability often reduce its overall therapeutic efficiency. These challenges require faster diagnosis, simultaneous therapy and a more personalized approach toward cancer management. To this end, small-molecule ‘theranostic’ agents have presented a viable solution combining diagnosis and therapy into a single platform. In this review, we present a summary of recent efforts in the design and optimization of metal-based small-molecule ‘theranostic’ anticancer agents. Importantly, we highlight the advantages of a theranostic candidate over the purely therapeutic or diagnostic agent in terms of evaluation of its biological properties.

Antibacterial pyrazoles: tackling resistant bacteria

Bacterial resistance to antibiotics threatens our progress in healthcare, modern medicine, food production and ultimately life expectancy. Antibiotic resistance is a global concern, which spreads rapidly across borders and continents due to rapid travel of people, animals and goods. Derivatives of metabolically stable pyrazole nucleus are known for their wide range of pharmacological properties, including antibacterial activities. This review highlights recent reports of pyrazole derivatives targeting different bacterial strains focusing on the drug-resistant variants. Pyrazole derivatives target different metabolic pathways of both Gram-positive and Gram-negative bacteria.

Progress in Alternative Strategies to Combat Antimicrobial Resistance: Focus on Antibiotics

Antibiotic resistance, and, in a broader perspective, antimicrobial resistance (AMR), continues to evolve and spread beyond all boundaries. As a result, infectious diseases have become more challenging or even impossible to treat, leading to an increase in morbidity and mortality. Despite the failure of conventional, traditional antimicrobial therapy, in the past two decades, no novel class of antibiotics has been introduced. Consequently, several novel alternative strategies to combat these (multi-) drug-resistant infectious microorganisms have been identified. The purpose of this review is to gather and consider the strategies that are being applied or proposed as potential alternatives to traditional antibiotics. These strategies include combination therapy, techniques that target the enzymes or proteins responsible for antimicrobial resistance, resistant bacteria, drug delivery systems, physicochemical methods, and unconventional techniques, including the CRISPR-Cas system. These alternative strategies may have the potential to change the treatment of multi-drug-resistant pathogens in human clinical settings.

The Nano-War Against Complement Proteins

Targeted drug delivery and nanomedicine hold the potential promise of delivering drugs solely to target organs or cell types, thus decreasing off-target side effects and improving efficacy. However, nano-scale drug carriers face several barriers to this goal, with one of the most formidable being the complement cascade. Complement proteins, especially C3, opsonize not just the microbes they evolved to contain, but also nanocarriers. This results in multiple problems, including marking the nanocarriers for clearance by leukocytes, likely fouling of the targeting moieties on nanocarriers, and release of toxins which produce deleterious local and systemic effects. Here, we review how complement achieves its blockade of nanomedicine, which nanocarrier materials properties best avoid complement, and current and future strategies to control complement to unleash nanomedicine’s potential.

Basics for Improved Use of Phages for Therapy

Blood-borne therapeutic phages and phage capsids increasingly reach therapeutic targets as they acquire more persistence, i.e., become more resistant to non-targeted removal from blood. Pathogenic bacteria are targets during classical phage therapy. Metastatic tumors are potential future targets, during use of drug delivery vehicles (DDVs) that are phage derived. Phage therapy has, to date, only sometimes been successful. One cause of failure is low phage persistence. A three-step strategy for increasing persistence is to increase (1) the speed of lytic phage isolation, (2) the diversity of phages isolated, and (3) the effectiveness and speed of screening phages for high persistence. The importance of high persistence-screening is illustrated by our finding here of persistence dramatically higher for coliphage T3 than for its relative, coliphage T7, in murine blood. Coliphage T4 is more persistent, long-term than T3. Pseudomonas chlororaphis phage 201phi2-1 has relatively low persistence. These data are obtained with phages co-inoculated and separately assayed. In addition, highly persistent phage T3 undergoes dispersal to several murine organs and displays tumor tropism in epithelial tissue (xenografted human oral squamous cell carcinoma). Dispersal is an asset for phage therapy, but a liability for phage-based DDVs. We propose increased focus on phage persistence—and dispersal—screening.

Antibody-drug conjugates: an evolving approach for melanoma treatment

Melanoma continues to be an aggressive and deadly form of skin cancer while therapeutic options are continuously developing in an effort to provide long-term solutions for patients. Immunotherapeutic strategies incorporating antibody-drug conjugates (ADCs) have seen varied levels of success across tumor types and represent a promising approach for melanoma. This review will explore the successes of FDA-approved ADCs to date compared to the ongoing efforts of melanoma-targeting ADCs. The challenges and opportunities for future therapeutic development are also examined to distinguish how ADCs may better impact individuals with malignancies such as melanoma.

Anti-Endotoxin 9-Meric Peptide with Therapeutic Potential for the Treatment of Endotoxemia

Inflammatory reactions activated by lipopolysaccharide (LPS) of gram-negative bacteria can lead to severe septic shock. With the recent emergence of multidrug-resistant gram-negative bacteria and a lack of efficient ways to treat resulting infections, there is a need to develop novel anti-endotoxin agents. Antimicrobial peptides have been noticed as potential therapeutic molecules for bacterial infection and as candidates for new antibiotic drugs. We previously designed the 9-meric antimicrobial peptide Pro9-3 and it showed high antimicrobial activity against gram-negative bacteria. Here, to further examine its potency as an anti-endotoxin agent, we examined the antiendotoxin activities of Pro9-3 and elucidated its mechanism of action. We performed a dye-leakage experiment and BODIPY-TR cadaverine and limulus amebocyte lysate assays for Pro9-3 as well as its lysine-substituted analogue and their enantiomers. The results confirmed that Pro9-3 targets the bacterial membrane and the arginine residues play key roles in its antimicrobial activity. Pro9-3 showed excellent LPS-neutralizing activity and LPS-binding properties, which were superior to those of other peptides. Saturation transfer difference-nuclear magnetic resonance experiments to explore the interaction between LPS and Pro9-3 revealed that Trp³ and Tlr⁷ in Pro9-3 are critical for attracting Pro9-3 to the LPS in the gram-negative bacterial membrane. Moreover, the anti-septic effect of Pro9-3 in vivo was investigated using an LPS-induced endotoxemia mouse model, demonstrating its dual activities: antibacterial activity against gram-negative bacteria and immunosuppressive effect preventing LPS-induced endotoxemia. Collectively, these results confirmed the therapeutic potential of Pro9-3 against infection of gram-negative bacteria.

History of penicillin

The history of penicillin was shaped by the contributions of numerous scientists. The ultimate result was the discovery of the mould Penicillium's antibacterial activity and the subsequent development of penicillins, the most widely used antibiotics. Following an accidental discovery of the mould, later identified as Penicillium rubens, as the source of the antibacterial principle (1928) and the production of a pure compound (1942), penicillin became the first naturally derived antibiotic. There is anecdotal evidence of ancient societies using moulds to treat infections and of awareness that various moulds inhibited bacterial growth. However, it is not clear if Penicillium species were the species traditionally used or if the antimicrobial substances produced were penicillin. In 1928, Alexander Fleming was the first to discover the antibacterial substance secreted by the Penicillium mould and concentrate the active substance involved, giving it the name penicillin. His success in treating Harry Lambert's streptococcal meningitis, an infection until then fatal, proved to be a critical moment in the medical use of penicillin. Many later scientists were involved in the stabilisation and mass production of penicillin and in the search for more productive strains of Penicillium. Among the most important were Ernst Chain and Howard Florey, who shared with Fleming the 1945 Nobel Prize in Physiology or Medicine.

Taking phototherapeutics from concept to clinical launch

More than four decades have passed since the first example of a light-activated (caged) compound was described. In the intervening years, a large number of light-responsive derivatives have been reported, several of which have found utility under a variety of in vitro conditions using cells and tissues. Light-triggered bioactivity furnishes spatial and temporal control, and offers the possibility of precision dosing and orthogonal communication with different biomolecules. These inherent attributes of light have been advocated as advantageous for the delivery and/or activation of drugs at diseased sites for a variety of indications. However, the tissue penetrance of light is profoundly wavelength-dependent. Only recently have phototherapeutics that are photoresponsive in the optical window of tissue (600-900 nm) been described. This Review highlights these recent discoveries, along with their limitations and clinical opportunities. In addition, we describe preliminary in vivo studies of prospective phototherapeutics, with an emphasis on the path that remains to be navigated in order to translate light-activated drugs into clinically useful therapeutics. Finally, the unique attributes of phototherapeutics is highlighted by discussing several potential disease applications.

Exploration into the origins and mobilization of di-hydrofolate reductase genes and the emergence of clinical resistance to trimethoprim

Trimethoprim is a synthetic antibacterial agent that targets folate biosynthesis by competitively binding to the di-hydrofolate reductase enzyme (DHFR). Trimethoprim is often administered synergistically with sulfonamide, another chemotherapeutic agent targeting the di-hydropteroate synthase (DHPS) enzyme in the same pathway. Clinical resistance to both drugs is widespread and mediated by enzyme variants capable of performing their biological function without binding to these drugs. These mutant enzymes were assumed to have arisen after the discovery of these synthetic drugs, but recent work has shown that genes conferring resistance to sulfonamide were present in the bacterial pangenome millions of years ago. Here, we apply phylogenetics and comparative genomics methods to study the largest family of mobile trimethoprim-resistance genes (dfrA). We show that most of the dfrA genes identified to date map to two large clades that likely arose from independent mobilization events. In contrast to sulfonamide resistance (sul) genes, we find evidence of recurrent mobilization in dfrA genes. Phylogenetic evidence allows us to identify novel dfrA genes in the emerging pathogen Acinetobacter baumannii, and we confirm their resistance phenotype in vitro. We also identify a cluster of dfrA homologues in cryptic plasmid and phage genomes, but we show that these enzymes do not confer resistance to trimethoprim. Our methods also allow us to pinpoint the chromosomal origin of previously reported dfrA genes, and we show that many of these ancient chromosomal genes also confer resistance to trimethoprim. Our work reveals that trimethoprim resistance predated the clinical use of this chemotherapeutic agent, but that novel mutations have likely also arisen and become mobilized following its widespread use within and outside the clinic. Hence, this work confirms that resistance to novel drugs may already be present in the bacterial pangenome, and stresses the importance of rapid mobilization as a fundamental element in the emergence and global spread of resistance determinants.

Extended Spectrum β-Lactamase (ESBL) Producing Escherichia coli in Pigs and Pork Meat in the European Union

The aim of this article is to review the fast and worldwide distribution of ESBL enzymes and to describe the role of the pork production chain as a reservoir and transmission route of ESBL-producing Escherichia coli and ESBLs in the European Union (EU). The use of β-lactam antibiotics in swine production and the prevalence of ESBL producing E. coli in fattening pigs and pork meat across Europe is analyzed. Overall, an increasing trend in the prevalence of presumptive ESBL producing E. coli in fattening pigs in the EU has been observed in the last decade, although with major differences among countries, linked to different approaches in the use of antimicrobials in pork production within the EU. Moreover, the various dissemination pathways of these bacteria along the pork production chain are described, along with factors at farm and slaughterhouse level influencing the risk of introducing or spreading ESBL producing bacteria throughout the food chain.

[Phenotypical antibiotic resistances of bacteriological isolates originating from pet, zoo and falconry birds]

OBJECTIVE

The prevalence of resistant bacteria in pet birds, zoo birds and falconry birds is still largely unknown. Therefore, antibiograms of rapidly-growing aerobic bacteria obtained from these birds were retrospectively evaluated.

MATERIAL AND METHODS

Between 2007 and 2016 a total of 1036 antibiograms were evaluated. The bacteria isolates originated from 811 birds of 20 zoological orders (mostly Psittaciformes [61.8 %] and Passeriformes [14.5 %] and from alive patients or pathological examinations. The birds were primarily kept in Southern Germany. Phenotypic in vitro sensitivity of bacterial isolates to various antibiotics was determined using a standardized agar diffusion test.

RESULTS

The most frequently examined bacteria species were Escherichia coli (n = 386 isolates), Staphylococcus (S.). aureus (n = 150), Enterobacter cloacae (n = 122), Klebsiella pneumoniae (n = 86) and Pseudomonas aeruginosa (n = 64). Resistance to at least one antibiotic agent was detected in 53.1 % of the E. coli isolates, most commonly to doxycycline (50.3 %) and ampicillin (46.1 %), as well as in 95.9 % of Enterococcus faecalis isolates and 78.0 % of Staphylococcus aureus isolates. Multidrug resistance to 3 or more antibiotic groups was frequent in S. aureus (37.3 % of isolates). Resistance rates were higher in isolates from pet birds and captive birds of prey than in isolates from zoo birds.Resistant isolates were more common in Psittaciformes than in Passeriformes. An increasing resistance rate for fluoroquinolones in E. coli (a minimum of 0 % in 2005 and a maximum of 27.3 % in 2011) and decreasing resistance rates for tetracyclines in S. aureus (a maximum of 38.2 % in 2007 and lowest values of 0 % in 2014 and 2015) were observed over the examined period.

CONCLUSION AND CLINICAL RELEVANCE

The detected resistance rates of bacteria in pet birds, zoo birds and falconry birds must be considered as being problematic. They indicate the importance of microbial sensitivity testing for a conscientious therapy of pet birds, zoo birds and falconry birds. Critical treatment situations may arise from infections with S. aureus.

Recent advances in phenotypic drug discovery

There is a great need for innovative new medicines to treat unmet medical needs. The discovery and development of innovative new medicines is extremely difficult, costly, and inefficient. In the last decade, phenotypic drug discovery (PDD) was reintroduced as a strategy to provide first-in-class medicines. PDD uses empirical, target-agnostic lead generation to identify pharmacologically active molecules and novel therapeutics which work through unprecedented drug mechanisms. The economic and scientific value of PDD is exemplified through game-changing medicines for hepatitis C virus, spinal muscular atrophy, and cystic fibrosis. In this short review, recent advances are noted for the implementation and de-risking of PDD (for compound library selection, biomarker development, mechanism identification, and safety studies) and the potential for artificial intelligence. A significant barrier in the decision to implement PDD is balancing the potential impact of a novel mechanism of drug action with an under-defined scientific path forward, with the desire to provide infrastructure and metrics to optimize return on investment, which a known mechanism provides. A means to address this knowledge gap in the future is to empower precompetitive research utilizing the empirical concepts of PDD to identify new mechanisms and pharmacologically active compounds.

Antimicrobial Usage in Horses: The Use of Electronic Data, Data Curation, and First Results

The usage of antimicrobial drugs (AMs) leads to an increase in antimicrobial resistance (AMR). Although different antimicrobial usage (AMU) monitoring programs exist for livestock animals in Germany, there is no such system for horses. However, with the increasing usage of electronic practice management software (EPMS), it is possible to analyze electronic field data generated for routine purposes. The aim of this study was to generate AMU data for German horses with data from the Clinic for Horses (CfH), University of Veterinary Medicine Hannover (TiHo), and in addition to show that different processes of data curation are necessary to provide results, especially considering quantitative indices. In this investigation, the number of antimicrobial doses used and the amount and percentage of active ingredients applied were calculated. Data contained all drugs administered between the 1st of January and the 31st of December 2017. A total of 2,168 horses were presented for veterinary care to the CfH and 34,432 drug applications were documented for 1,773 horses. Of these, 6,489 (18.85%) AM applications were documented for 837 (47.21%) horses. In 2017, 162.33 kg of active ingredients were documented. The most commonly used antibiotic classes were sulfonamides (84.32 kg; 51.95 %), penicillins (30.11 kg; 18.55%) and nitroimidazoles (24.84 kg; 15.30%). In 2017, the proportion of Critically Important Antibiotics (CIA)-Highest Priority used was 0.15% (0.24 kg) and the proportion of CIA-High Priority used was 20.85% (33.85 kg). Of the total 9,402 entries of antimicrobial active ingredients, the three with the largest number used were sulfonamides [n = 2,798 (29.76%)], trimethoprim [n = 2,757 (29.76%)] and aminoglycosides [n = 1,381 (14.69%)]. Comparison between Administered Daily Dose (ADA) and Recommended Daily Dose of CfH (RDD_CfH), showed that 3.26% of ADA were below RDD_CfH, 3.18% exceeded RDD_CfH and 93.55% were within the range around RDD_CfH. This study shows that data generated by an EPMS can be evaluated once the method is set up and validated. The method can be transferred to evaluate data from the EPMS of other clinics or animal species, but the transferability depends on the quality of AMU documentation and close cooperation with respective veterinarians is essential.

Antiseptic Effect of Ps-K18: Mechanism of Its Antibacterial and Anti-Inflammatory Activities

Recently, bioactive peptides have attracted attention for their therapeutic applications in the pharmaceutical industry. Among them, antimicrobial peptides are candidates for new antibiotic drugs. Since pseudin-2 (Ps), isolated from the skin of the paradoxical frog Pseudis paradoxa, shows broad-spectrum antibacterial activity with high cytotoxicity, we previously designed Ps-K18 with a Lys substitution for Leu18 in Ps, which showed high antibacterial activity and low toxicity. Here, we examined the potency of Ps-K18, aiming to develop antibiotics derived from bioactive peptides for the treatment of Gram-negative sepsis. We first investigated the antibacterial mechanism of Ps-K18 based on confocal micrographs and field emission scanning electron microscopy, confirming that Ps-K18 targets the bacterial membrane. Anti-inflammatory mechanism of Ps-K18 was investigated by secreted alkaline phosphatase reporter gene assays and RT-PCR, which revealed that Ps-K18 activates innate defense via Toll-like receptor 4-mediated nuclear factor-kappa B signaling pathways. Moreover, we investigated the antiseptic effect of Ps-K18 using a lipopolysaccharide or Escherichia coli K1-induced septic shock mouse model. Ps-K18 significantly reduced bacterial growth and inflammatory responses in the septic shock model. Ps-K18 showed low renal and liver toxicity and attenuated lung damage effectively. This study suggests that Ps-K18 is a potent peptide antibiotic that could be applied therapeutically to Gram-negative sepsis.

Antibiotic Discovery: Where Have We Come from, Where Do We Go?

Given the increase in antibiotic-resistant bacteria, alongside the alarmingly low rate of newly approved antibiotics for clinical usage, we are on the verge of not having effective treatments for many common infectious diseases. Historically, antibiotic discovery has been crucial in outpacing resistance and success is closely related to systematic procedures—platforms—that have catalyzed the antibiotic golden age, namely the Waksman platform, followed by the platforms of semi-synthesis and fully synthetic antibiotics. Said platforms resulted in the major antibiotic classes: aminoglycosides, amphenicols, ansamycins, beta-lactams, lipopeptides, diaminopyrimidines, fosfomycins, imidazoles, macrolides, oxazolidinones, streptogramins, polymyxins, sulphonamides, glycopeptides, quinolones and tetracyclines. During the genomics era came the target-based platform, mostly considered a failure due to limitations in translating drugs to the clinic. Therefore, cell-based platforms were re-instituted, and are still of the utmost importance in the fight against infectious diseases. Although the antibiotic pipeline is still lackluster, especially of new classes and novel mechanisms of action, in the post-genomic era, there is an increasingly large set of information available on microbial metabolism. The translation of such knowledge into novel platforms will hopefully result in the discovery of new and better therapeutics, which can sway the war on infectious diseases back in our favor.

[Evolution of treatment of syphilis through history]

In this article, we present a historical revision of syphilis treatment since the end of the XV century up until the current days. For centuries, it was understood that syphilis had been brought to Spain by Columbus after coming back from America. It became an epidemic soon after. Later on, it was spread all over Europe. The chronologic and geographic origin of this illness have been debated in recent years, however, there has been no agreement about it as yet. Mercury was the main used therapy for four and a half centuries, until the discovery of penicillin in 1943. This discovery changed the therapeutic approach to syphilis since then. Other remedies were used during this period. Guaiacum was one of them, but it was dismissed in the mid-sixteenth century. Iodides were also used, especially in the tertiary symptoms of the disease. The discovery of arsphenamine (Salvarsan) at the beginning of the XX century, used by itself at its onset and associated to mercury or bismuth later on, was a significant therapeutic contribution. Bismuth was in itself a great therapeutic asset. It displaced the use of mercury in an important way until 1943, when the appearance of penicillin became the treatment of choice.

Antibacterial properties of doped nanoparticles

Nanoparticles have high potential as antibacterial agents, owing to their ability to produce reactive oxygen species (ROS). Recent studies have indicated that this ROS generation is highly affected by the modification of band structure by the introduction of various dopant materials into them. Thus, doped nanoparticles have been extensively studied in the recent literature. The types of dopants, synthesis techniques, and experimental parameters have been found to affect the overall electronic structure of the material, leading to varied antibacterial efficiency. This review summarizes some of the prominent dopant nanomaterials, various methods of synthesizing doped nanoparticles used against bacterial cells, and the main factors involved in it. Despite the extensive research on the mechanism of the antibacterial action, it is still poorly understood mainly due to the inherent complexities and dynamics in cell membranes. Some of the major proposed mechanisms of action of each kind of dopant nanomaterial have also been reported in this work, focusing on the bacterial cell structure.

Biogenic Nanosilver against Multidrug-Resistant Bacteria (MDRB)

Multidrug-resistant bacteria (MDRB) are extremely dangerous and bring a serious threat to health care systems as they can survive an attack from almost any drug. The bacteria's adaptive way of living with the use of antimicrobials and antibiotics caused them to modify and prevail in hostile conditions by creating resistance to known antibiotics or their combinations. The emergence of nanomaterials as new antimicrobials introduces a new paradigm for antibiotic use in various fields. For example, silver nanoparticles (AgNPs) are the oldest nanomaterial used for bactericide and bacteriostatic purposes. However, for just a few decades these have been produced in a biogenic or bio-based fashion. This review brings the latest reports on biogenic AgNPs in the combat against MDRB. Some antimicrobial mechanisms and possible silver resistance traits acquired by bacteria are also presented. Hopefully, novel AgNPs-containing products might be designed against MDR bacterial infections.

Organic Arsenicals as Functional Motifs in Polymer and Biomaterials Science

Arsenic (As) exhibits diverse (bio)chemical reactivity and biological activity depending upon its oxidation state. However, this distinctive reactivity has been largely overlooked across many fields owing to concerns regarding the toxicity of arsenic. Recently, a clinical renaissance in the use of arsenicals, including organic arsenicals that are known to be less toxic than inorganic arsenicals, alludes to the possibility of broader acceptance and application in the field of polymer and biomaterials science. Here, current examples of polymeric/macromolecular arsenicals are reported to stimulate interest and highlight their potential as a novel platform for functional, responsive, and bioactive materials.

Addressing the Challenges of Tuberculosis: A Brief Historical Account

Tuberculosis (TB) is a highly contagious disease that still poses a threat to human health. Mycobacterium tuberculosis (MTB), the pathogen responsible for TB, uses diverse ways in order to survive in a variety of host lesions and to subsequently evade immune surveillance; as a result, fighting TB and its associated multidrug resistance has been an ongoing challenge. The aim of this review article is to summarize the historical sequence of drug development and use in the fight against TB, with a particular emphasis on the decades between World War II and the dawn of the twenty first century (2000).

A Novel Spiro-Heterocyclic Compound Identified by the Silkworm Infection Model Inhibits Transcription in Staphylococcus aureus

Synthetic compounds are a vital source of antimicrobial agents. To uncover therapeutically effective antimicrobial agents from a chemical library, we screened over 100,000 synthetic compounds for in vitro antimicrobial activity against methicillin-resistant Staphylococcus aureus and evaluated the in vivo therapeutic effectiveness of the hits in S. aureus-infected silkworms. Three antimicrobial agents exhibited therapeutic effects in the silkworm infection model. One of these, GPI0363, a novel spiro-heterocyclic compound, was bacteriostatic and inhibited RNA synthesis in S. aureus cells. GPI0363-resistant S. aureus strains harbored a point mutation in the gene encoding the primary sigma factor, SigA, of RNA polymerase, and this mutation was responsible for the resistance to GPI0363. We further revealed that GPI0363 could bind to SigA, inhibit promoter-specific transcription in vitro, and prolong the survival of mice infected with methicillin-resistant S. aureus. Thus, GPI0363 is an attractive candidate therapeutic agent against drug-resistant S. aureus infections.

Origins of Combination Therapy for Tuberculosis: Lessons for Future Antimicrobial Development and Application

Tuberculosis is a global health problem that causes the death of approximately 1.5 million people worldwide each year (WHO, p. 1-126, Global Tuberculosis Report, 2015). Treatment of drug-susceptible tuberculosis requires combination antimicrobial therapy with a minimum of four antimicrobial agents applied over the course of 6 months. The first instance of combination antimicrobial therapy applied to tuberculosis was the joint use of streptomycin and para-aminosalicylic acid as documented by the Medical Research Council of the United Kingdom in 1950. These antimicrobial drugs were the product of many decades of investigation into both organism-derived antibiotics and synthetic chemotherapy and were the first agents in those respective categories to show substantial clinical efficacy and widespread use for tuberculosis. The events leading to the discovery and application of these two agents demonstrate that investments in all aspects of research, from basic science to clinical application, are necessary for the continued success of science in finding treatments for human disease. This observation is especially worth considering given the expanded role that combination therapy may play in combating the current rise in resistance to antimicrobial drugs.

History of Antibiotics Research

For thousands of years people were delivered helplessly to various kinds of infections, which often reached epidemic proportions and have cost the lives of millions of people. This is precisely the age since mankind has been thinking of infectious diseases and the question of their causes. However, due to a lack of knowledge, the search for strategies to fight, heal, and prevent the spread of communicable diseases was unsuccessful for a long time. It was not until the discovery of the healing effects of (antibiotic producing) molds, the first microscopic observations of microorganisms in the seventeenth century, the refutation of the abiogenesis theory, and the dissolution of the question "What is the nature of infectious diseases?" that the first milestones within the history of antibiotics research were set. Then new discoveries accelerated rapidly: Bacteria could be isolated and cultured and were identified as possible agents of diseases as well as producers of bioactive metabolites. At the same time the first synthetic antibiotics were developed and shortly thereafter, thousands of synthetic substances as well as millions of soil borne bacteria and fungi were screened for bioactivity within numerous microbial laboratories of pharmaceutical companies. New antibiotic classes with different targets were discovered as on assembly line production. With the beginning of the twentieth century, many of the diseases which reached epidemic proportions at the time-e.g., cholera, syphilis, plague, tuberculosis, or typhoid fever, just to name a few, could be combatted with new discovered antibiotics. It should be considered that hundred years ago the market launch of new antibiotics was significantly faster and less complicated than today (where it takes 10-12 years in average between the discovery of a new antibiotic until the launch). After the first euphoria it was quickly realized that bacteria are able to develop, acquire, and spread numerous resistance mechanisms. Whenever a new antibiotic reached the market it did not take long until scientists observed the first resistant germs. Since the marketing of the first antibiotic there is a neck-on-neck race between scientists who discover natural or develop semisynthetic and synthetic bioactive molecules and bacteria, which have developed resistance mechanisms. The emphasis of this chapter is to give an overview of the history of antibiotics research. The situation within the pre-antibiotic era as well as in the early antibiotic era will be described until the Golden Age of Antibiotics will conclude this time travel. The most important antibiotic classes, information about their discovery, activity spectrum, mode of action, resistance mechanisms, and current application will be presented.