A brief history of antibiotics and select advances in their synthesis

Is shorter also better in the treatment of Clostridioides difficile infection?

OBJECTIVES

To assess the effectiveness of shortened regimens of vancomycin or fidaxomicin in the treatment of Clostridioides difficile infection (CDI).

METHODS

Adult patients with CDI hospitalized from January 2022 to May 2023 were included in this observational study. In patients with CDI treated with vancomycin or fidaxomicin, antibiotic treatment was discontinued after either 5 or 7 days of vancomycin or 5 days of fidaxomicin if there was a clinical response and improvement in laboratory parameters. The control cohort was treated with the standard 10 day regimen of either vancomycin or fidaxomicin. The follow-up was 60 days. Causative C. difficile strains were characterized by ribotyping and toxin gene detection when available.

RESULTS

Twenty-five patients (median age 76 years) received shortened treatment with vancomycin (n = 21), or fidaxomicin (n = 4). Five cases fulfilled the criteria for severe CDI. Twenty-three patients completed follow-up; two died from causes other than CDI, and two developed recurrent CDI (8.0%). Ribotypes (RTs) 001 and 014 were the most prevalent with 20% each. In two C. difficile isolates, binary toxin genes were detected (RTs 078 and 023). In the control group of 22 patients recurrent CDI developed in 5 patients (22.7%). No statistically significant differences were found between the groups.

CONCLUSIONS

Shortened treatment regimens for CDI with vancomycin and fidaxomicin were shown to be effective in our cohort of patients compared with 10 days of treatment. The recurrence rate was lower in the study group. A larger, prospective, double-blind, randomized, multicentre study is needed to support our findings.

Investigating the Antimicrobial Effects of a Novel Peptide Derived From Listeriolysin S on S aureus, E coli, and L plantarum: An In Silico and In Vitro Study

Aims

The emergence of antibiotic resistance is one of the most significant issues today. Modifying antimicrobial peptides (AMPs) can improve their effects. In this study, the active region of Listeriolysin S (LLS) as a peptidic toxin has been recognized, and its antibacterial properties have been evaluated by modifying that region.

Methods

After extracting the sequence, the structure of LLS was predicted by PEP-FOLD3. AntiBP and AMPA servers identified its antimicrobial active site. It was modified by adding arginine residue to its 3- and N-terminal regions. Its antimicrobial properties on Staphylococcus aureus, Escherichia coli, and Lactobacillus Plantarum were estimated.

Findings

The results of AntiBP and AntiBP servers demonstrated that a region of 15 amino acids has the most antimicrobial properties (score = 1.696). After adding arginine to the chosen region, the physicochemical evaluation and antimicrobial properties revealed that the designed peptide is a stable AMP with a positive charge of 4, which is not toxic to human erythrocyte cells and has antigenic properties. The results of in vitro and colony counting indicated that at different hours, it caused a significant reduction in the count of S aureus, E coli, and L Plantarum compared with the control sample.

Conclusions

Upcoming research implies that identifying and enhancing the active sites of natural peptides can help combat bacteria.

What is the role of microbial biotechnology and genetic engineering in medicine?

Microbial products are essential for developing various therapeutic agents, including antibiotics, anticancer drugs, vaccines, and therapeutic enzymes. Genetic engineering techniques, functional genomics, and synthetic biology unlock previously uncharacterized natural products. This review highlights major advances in microbial biotechnology, focusing on gene-based technologies for medical applications.

Antimicrobials: An update on new strategies to diversify treatment for bacterial infections

Ninety-five years after Fleming's discovery of penicillin, a bounty of antibiotic compounds have been discovered, modified, or synthesised. Diversification of target sites, improved stability and altered activity spectra have enabled continued antibiotic efficacy, but overwhelming reliance and misuse has fuelled the global spread of antimicrobial resistance (AMR). An estimated 1.27 million deaths were attributable to antibiotic resistant bacteria in 2019, representing a major threat to modern medicine. Although antibiotics remain at the heart of strategies for treatment and control of bacterial diseases, the threat of AMR has reached catastrophic proportions urgently calling for fresh innovation. The last decade has been peppered with ground-breaking developments in genome sequencing, high throughput screening technologies and machine learning. These advances have opened new doors for bioprospecting for novel antimicrobials. They have also enabled more thorough exploration of complex and polymicrobial infections and interactions with the healthy microbiome. Using models of infection that more closely resemble the infection state in vivo, we are now beginning to measure the impacts of antimicrobial therapy on host/microbiota/pathogen interactions. However new approaches are needed for developing and standardising appropriate methods to measure efficacy of novel antimicrobial combinations in these contexts. A battery of promising new antimicrobials is now in various stages of development including co-administered inhibitors, phages, nanoparticles, immunotherapy, anti-biofilm and anti-virulence agents. These novel therapeutics need multidisciplinary collaboration and new ways of thinking to bring them into large scale clinical use.

Personalized Drug Therapy: Innovative Concept Guided With Proteoformics

Personalized medicine can reduce adverse effects, enhance drug efficacy, and optimize treatment outcomes, which represents the essence of personalized medicine in the pharmacy field. Protein drugs are crucial in the field of personalized drug therapy and are currently the mainstay, which possess higher target specificity and biological activity than small-molecule chemical drugs, making them efficient in regulating disease-related biological processes, and have significant potential in the development of personalized drugs. Currently, protein drugs are designed and developed for specific protein targets based on patient-specific protein data. However, due to the rapid development of two-dimensional gel electrophoresis and mass spectrometry, it is now widely recognized that a canonical protein actually includes multiple proteoforms, and the differences between these proteoforms will result in varying responses to drugs. The variation in the effects of different proteoforms can be significant and the impact can even alter the intended benefit of a drug, potentially making it harmful instead of lifesaving. As a result, we propose that protein drugs should shift from being targeted through the lens of protein (proteomics) to being targeted through the lens of proteoform (proteoformics). This will enable the development of personalized protein drugs that are better equipped to meet patients' specific needs and disease characteristics. With further development in the field of proteoformics, individualized drug therapy, especially personalized protein drugs aimed at proteoforms as a drug target, will improve the understanding of disease mechanisms, discovery of new drug targets and signaling pathways, provide a theoretical basis for the development of new drugs, aid doctors in conducting health risk assessments and making more cost-effective targeted prevention strategies conducted by artificial intelligence/machine learning, promote technological innovation, and provide more convenient treatment tailored to individualized patient profile, which will benefit the affected individuals and society at large.

Stereoselective synthesis of thailandamide A methyl ester

A convergent strategy for the stereoselective synthesis of the methyl ester of the structurally challenging and highly labile antibacterial polyene polyketide natural product thailandamide A has been developed. The key steps include the Zincke aldehyde reaction, Stille cross coupling, Negishi reaction, Julia-Kocienski olefination, cross metathesis, and the less explored Pd(I)-based Heck coupling to access different unsaturation bonds. Additionally, Urpi acetal aldol, Evans methylation, and Crimmins acetate aldol reactions were employed to construct four out of six asymmetric centers of the molecule.

Point prevalence of antibiotic usage in major referral hospital in Turkey

INTRODUCTION

The most important and undesirable consequence of inappropriate antibiotic use is the spread of antibiotic resistance, increased adverse effects, increased mortality and healthcare costs. We aimed to assess antibiotic usage characteristics in inpatient setting in our center.

MATERIALS AND METHODS

A one-day, single center point-prevalence study was carried out on June 9th 2021, in Ankara City Hospital in Turkey. Data of antibiotic consumption, appropriateness of usage and predictors of inappropriate use in adult patients were evaluated.

RESULTS

Out of 2640 adult patients, 893 (33.8%) were receiving at least one antibiotic. A total of 1212 antibiotic prescriptions with an average of 1.44±0.64 were found. Antibiotics were most commonly used for therapeutic purpose (84.7%), followed by surgical prophylaxis (11.6%). Majority of therapeutically used antibiotics were empirical (67.9%). Infectious diseases consultation was present in 68.3% with a compliance rate of 95.7%. Rate of inappropriate use was 20%. The most frequent cause of inappropriateness was unnecessary use (52.5%). Most commonly and most inappropriately used antibiotics were carbapenems (17.5%) and first generation cephalosporins (38.7%), respectively. Most of the inappropriateness observed in first-generation cephalosporins was due to inappropriate longer surgical prophylaxis. While age is an independent risk factor for inappropriate antibiotic use (p = 0.042), COVID-19 unit admission, use for therapeutic purpose and infectious diseases consultation were protective factors (p<0.001, p<0.001, p<0.001).

CONCLUSION

Rate of inappropriate use was low, but inappropriate surgical prophylaxis remains an important problem in surgical units. There is a considerable need to implement an antimicrobial stewardship program that focuses on surgical prophylaxis practices.

Characterization, antibacterial, and cytotoxic activities of silver nanoparticles using the whole biofilm layer as a macromolecule in biosynthesis

Recently, multi-drug resistant (MDR) bacteria are responsible for a large number of infectious diseases that can be life-threatening. Globally, new approaches are targeted to solve this essential issue. This study aims to discover novel antibiotic alternatives by using the whole components of the biofilm layer as a macromolecule to synthesize silver nanoparticles (AgNPs) as a promising agent against MDR. In particular, the biosynthesized biofilm-AgNPs were characterized using UV-Vis spectroscopy, electron microscopes, Energy Dispersive X-ray (EDX), zeta sizer and potential while their effect on bacterial strains and normal cell lines was identified. Accordingly, biofilm-AgNPs have a lavender-colored solution, spherical shape, with a size range of 20-60 nm. Notably, they have inhibitory effects when used on various bacterial strains with concentrations ranging between 12.5 and 25 µg/mL. In addition, they have an effective synergistic effect when combined with phage ZCSE9 to inhibit and kill Salmonella enterica with a concentration of 3.1 µg/mL. In conclusion, this work presents a novel biosynthesis preparation of AgNPs using biofilm for antibacterial purposes to reduce the possible toxicity by reducing the MICs using phage ZCSE9.

Bioengineering the Antimicrobial Activity of Yeast by Recombinant Thanatin Production

The global spread of antibiotic resistance marks the end of the era of conventional antibiotics. Mankind desires new molecular tools to fight pathogenic bacteria. In this regard, the development of new antimicrobials based on antimicrobial peptides (AMPs) is again of particular interest. AMPs have various mechanisms of action on bacterial cells. Moreover, AMPs have been reported to be efficient in preclinical studies, demonstrating a low level of resistance formation. Thanatin is a small, beta-hairpin antimicrobial peptide with a bacterial-specific mode of action, predetermining its low cytotoxicity toward eukaryotic cells. This makes thanatin an exceptional candidate for new antibiotic development. Here, a microorganism was bioengineered to produce an antimicrobial agent, providing novel opportunities in antibiotic research through the directed creation of biocontrol agents. The constitutive heterologous production of recombinant thanatin (rThan) in the yeast Pichia pastoris endows the latter with antibacterial properties. Optimized expression and purification conditions enable a high production level, yielding up to 20 mg/L of rThan from the culture medium. rThan shows a wide spectrum of activity against pathogenic bacteria, similarly to its chemically synthesized analogue. The designed approach provides new avenues for AMP engineering and creating live biocontrol agents to fight antibiotic resistance.

Oligomeric phloroglucinols with hAChE inhibitory and antibacterial activities from tropic Rhodomyrtus tomentosa

Alzheimer's diseases (AD) and other infectious diseases caused by drug-resistance bacteria have posed a serious threat to human lives and global health. With the aim to search for human acetylcholinesterase (hAChE) inhibitors and antibacterial agents from medicinal plants, 16 phloroglucinol oligomers, including two new phloroglucinol monomers (1a and 1b), four new phloroglucinol dimers (3a, 3b, 4b, and 5a), six new phloroglucinol trimers (6a, 6b, 7a, 7b, 8a, and 8b), and two naturally occurring phloroglucinol monomers (2a and 2b), along with two known congeners (4a and 5b), were purified from the leaves of tropic Rhodomyrtus tomentosa. The structures and absolute configurations of these new isolates were unequivocally established by comprehensive analyses of their spectroscopic data (NMR and HRESIMS), ECD calculation, and single crystal X-ray diffraction. Structurally, 3a/3b shared a rare C-5' formyl group, whereas 6a/6b possessed a unique C-7' aromatic ring. In addition, 7a/7b and 8a/8b were rare phloroglucinol trimers with a bis-furan and a C-6' hemiketal group. Pharmacologically, the mixture of 3a and 3b showed the most potent human acetylcholinesterase (hAChE) inhibitory activity with an IC50 value of 1.21 ± 0.16 μM. The molecular docking studies of 3a and 3b in the hAChE binding sites were performed, displaying good agreement with the in vitro inhibitory effects. In addition, the mixture of 3a and 3b displayed the most significant anti-MRSA (methicillin-resistant Staphylococcus aureus) with MIC and MBC values of both 0.50 μg/mL, and scanning electron microscope (SEM) studies revealed that they could destroy the biofilm structures of MRSA. The findings provide potential candidates for the further development of anti-AD and anti-bacterial agents.

A decennial study of the trend of antibiotic studies in China

Antibiotics are one of the greatest inventions in human history and are used worldwide on an enormous scale. Besides its extensive usage in medical and veterinary arenas to treat and prevent the infection, its application is very prominent in other fields, including agriculture, aquaculture, and horticulture. In recent decades, the increased consumption of antibiotics in China saw a vast increase in its production and disposal in various environments. However, in this post-antibiotic era, the abuse and misuse of these valuable compounds could lead to the unreversible consequence of drug resistance. In China, antibiotics are given a broad discussion in various fields to reveal their impact on both human/animals health and the environment. To our knowledge, we are the first paper to look back at the development trend of antibiotic-related studies in China with qualitative and quantitative bibliometric analysis from the past decades. Our study identified and analyzed 5559 papers from its inception (1991) to December 6, 2021, from the Web of Science Core Collection database. However, with few authors and institutions focusing on long-term studies, we found the quality of contributions was uneven. Studies mainly focused on areas such as food science, clinical research, and environmental studies, including molecular biology, genetics and environmental, ecotoxicology, and nutrition, which indicate possible primary future trends. Our study reports on including potentially new keywords, studies' milestones, and their contribution to antibiotic research. We offer potential topics that may be important in upcoming years that could help guide future research.

Exploring the arsenal of antimicrobial peptides: Mechanisms, diversity, and applications

Antimicrobial peptides (AMPs) are essential for defence against pathogens in all living organisms and possessed activities against bacteria, fungi, viruses, parasites and even cancer cells. AMPs are short peptides containing 12-100 amino acids conferring a net positive charge and an amphiphilic property in most cases. Although, anionic AMPs also exist. AMPs can be classified based on the types of secondary structures, charge, hydrophobicity, amino acid composition, length, etc. Their mechanism of action usually includes a membrane disruption process through pore formation (three different models have been described, barrel-stave, toroidal or carpet model) but AMPs can also penetrate and impair intracellular functions. Besides their activity against pathogens, they have also shown immunomodulatory properties in complex scenarios through many different interactions. The aim of this review to summarize knowledge about AMP's and discuss the potential application of AMPs as therapeutics, the challenges due to their limitations, including their susceptibility to degradation, the potential generation of AMP resistance, cost, etc. We also discuss the current FDA-approved drugs based on AMPs and strategies to circumvent natural AMPs' limitations.

National Cohort Study of Resource Utilization in Older Adults With Emergency General Surgery Conditions

INTRODUCTION

Prior studies have sought to describe Emergency General Surgery (EGS) burden, but a detailed description of resource utilization for both operative and nonoperative management of EGS conditions has not been undertaken.

METHODS

Patient and hospital characteristics were extracted from Medicare data, 2015-2018. Operations, nonsurgical procedures, and other resources (i.e., radiology) were defined using Current Procedural Terminology codes.

RESULTS

One million eight hundred two thousand five hundred forty-five patients were included in the cohort. The mean age was 74.7 y and the most common diagnoses were upper gastrointestinal. The majority of hospitals were metropolitan (75.1%). Therapeutic radiology services were available in 78.4% of hospitals and operating rooms or endoscopy suites were available in 92.5% of hospitals. There was variability in resource utilization across EGS subconditions, with hepatobiliary (26.4%) and obstruction (23.9%) patients most frequently undergoing operation.

CONCLUSIONS

Treatment of EGS diseases in older adults involves several interventional resources. Changes in EGS models, acute care surgery training, and interhospital care coordination may be beneficial to the treatment of EGS patients.

Unraveling the Role of Metals and Organic Acids in Bacterial Antimicrobial Resistance in the Food Chain

Antimicrobial resistance (AMR) has a significant impact on human, animal, and environmental health, being spread in diverse settings. Antibiotic misuse and overuse in the food chain are widely recognized as primary drivers of antibiotic-resistant bacteria. However, other antimicrobials, such as metals and organic acids, commonly present in agri-food environments (e.g., in feed, biocides, or as long-term pollutants), may also contribute to this global public health problem, although this remains a debatable topic owing to limited data. This review aims to provide insights into the current role of metals (i.e., copper, arsenic, and mercury) and organic acids in the emergence and spread of AMR in the food chain. Based on a thorough literature review, this study adopts a unique integrative approach, analyzing in detail the known antimicrobial mechanisms of metals and organic acids, as well as the molecular adaptive tolerance strategies developed by diverse bacteria to overcome their action. Additionally, the interplay between the tolerance to metals or organic acids and AMR is explored, with particular focus on co-selection events. Through a comprehensive analysis, this review highlights potential silent drivers of AMR within the food chain and the need for further research at molecular and epidemiological levels across different food contexts worldwide.

ZnO and Au nanoparticles supported highly sensitive and selective electrochemical sensor based on molecularly imprinted polymer for sulfaguanidine and sulfamerazine detection

This study aimed to develop a molecularly imprinted polymer (MIP) sensor using electropolymerization of thiophene acetic acid monomer around template molecules, sulfaguanidine (SGN) and sulfamerazine (SMR), for selective and sensitive detection of both antibiotics. Au nanoparticles were then deposited on the modified electrode surface, and SGN and SMR were extracted from the resulting layer. Surface characterization, changes in the oxidation peak current of both analytes, and investigation of the electrochemical properties of the MIP sensor were examined using scanning electron microscopy, cyclic voltammetry, and differential pulse voltammetry. The developed MIP sensor with Au nanoparticles showed a detection limit of 0.030 µmol L-1 and 0.046 µmol L-1 for SGN and SMR, respectively, with excellent selectivity in the presence of interferents. The sensor was successfully used for SGN and SMR analysis in human fluids, including blood serum and urine, with excellent stability and reproducibility.

Biosynthesis of silver nanoparticles (Ag-NPs) using Senna alexandrina grown in Saudi Arabia and their bioactivity against multidrug-resistant pathogens and cancer cells

There is no doubt that the risk of drug-resistant pathogens and cancer diseases is on the rise. So, the goal of this study was to find out how effective silver nanoparticles (Ag-NPs) made by Senna alexandrina are at fighting these threats. In this work, S. alexandrina collected from Medina, Saudi Arabia was used and the biosynthesis method was applied to produce the Ag-NPs. The characterization of Ag-NPs was done using different analytical techniques, including UV spectroscopy, FT-IR, TEM, and XRD analysis. The MIC, MBC, and MTT protocols were applied to confirm the bioactivity of the Ag-NPs as antibacterial and anticancer bioagents. The findings reported indicating that the aqueous extract of S. alexandrina leaves, grown naturally in Saudi Arabia, is ideal for the production of bioactive Ag-NPs. The hydroxyl, aliphatic, alkene, N-H bend of primary amines, C-H bonds, and C-O bonds of alcohol were detected in this product. The small, sphere-shaped particles (4-7 nm) were the most prevalent among the bioactive Ag-NPs produced in this work. These nanoparticles inhibited some important multidrug-resistant pathogens (MDRPs) (Escherichia coli, Acinetobacter baumanii/haemolyticus, Staphylococcus epidermidis, and Methicillin-resistant Staphylococcus aureus (MRSA)), as well as their ability to inhibit breast cancer cells (MCF-7 cells). The MIC of Ag-NPs ranged from 0.03 to 0.6 mg/mL, while their MBC ranged from 0.06 to 2.5 mg/mL. Anticancer activity test showed that IC₅₀ of the Ag-NPs against tested breast cancer cells was 61.9 ± 3.8 µg/mL. According to the current results, biosynthesis using S. alexandrina leaves grown naturally in Saudi Arabia was an ideal technique for producing bioactive Ag-NPs that could be used to combat a variety of MDRPs and cancer diseases.

Spatial analysis of antimicrobial resistance in the environment. A systematic review

Antimicrobial resistance (AMR) is a global major health concern. Spatial analysis is considered an invaluable method in health studies. Therefore, we explored the usage of spatial analysis in Geographic Information Systems (GIS) in studies on AMR in the environment. This systematic review is based on database searches, a content analysis, ranking of the included studies according to the preference ranking organization method for enrichment evaluations (PROMETHEE) and estimation of data points per km2. Initial database searches resulted in 524 records after removal of duplicates. After the last stage of full text screening, 13 greatly heterogeneous articles with diverse study origins, methods and design remained. In the majority of studies, the data density was considerably less than one sampling site per km2 but exceeded 1,000 sites per km2 in one study. The results of the content analysis and ranking showed a variation between studies that primarily used spatial analysis and those that used spatial analysis as a sec ondary method. We identified two distinct groups of GIS methods. The first was focused on sample collection and laboratory testing, with GIS as supporting method. The second group used overlay analysis as the primary method to combine datasets in a map. In one case, both methods were combined. The low number of articles that met our inclusion criteria highlights a research gap. Based on the findings of this study we encourage application of GIS to its full potential in studies of AMR in the environment.

Translating phage therapy into the clinic: Recent accomplishments but continuing challenges

Phage therapy is a medical form of biological control of bacterial infections, one that uses naturally occurring viruses, called bacteriophages or phages, as antibacterial agents. Pioneered over 100 years ago, phage therapy nonetheless is currently experiencing a resurgence in interest, with growing numbers of clinical case studies being published. This renewed enthusiasm is due in large part to phage therapy holding promise for providing safe and effective cures for bacterial infections that traditional antibiotics acting alone have been unable to clear. This Essay introduces basic phage biology, provides an outline of the long history of phage therapy, highlights some advantages of using phages as antibacterial agents, and provides an overview of recent phage therapy clinical successes. Although phage therapy has clear clinical potential, it faces biological, regulatory, and economic challenges to its further implementation and more mainstream acceptance.

Amino-functionalized Fe(III)-Based MOF for the high-efficiency extraction and ultrasensitive colorimetric detection of tetracycline

In order to achieve the simultaneous extraction and detection of tetracycline (TC) in milk, the amino-functionalized Fe-based metal-organic frameworks (NH₂-MIL-88B) was synthesized via a solvothermal method with Fe³⁺ and 2-aminoterephthalic acid (NH₂-BDC) as precursor. Thanks to the unique structure of NH₂-MIL-88B, it could be used to highly effective extract of TC in milk. More interestedly, the introduced -NH₂ could react with -OH from TC by a hydrogen-bonding interaction to cause the electronic interactions that enhances the peroxidase-like activity of NH₂-MIL-88B, which result in the enhancement of Fenton reaction by the transfer of the electron between TC and NH₂-MIL-88B. Under the optimal testing conditions, the linear absorbance response is well correlated with the TC concentration range of 50-1000 nM, which can reach a low LOD of 46.75 nM. Besides, the sensor exhibits excellent selectivity to TC, and the proposed strategy can also be applied to milk with good recovery (83.33-107.00%). Finally, the NH₂-MIL-88B and cellulose acetate (CA) are combined to form nanozyme hybrid membranes through the non-solvent induced phase separation method, which can be used to prepare point-of-care testing (POCT) for rapid and in-situ detection of TC.

Antimicrobial resistance in methicillin-resistant staphylococcus aureus

In the medical community, antibiotics are revered as a miracle because they stop diseases brought on by pathogenic bacteria. Antibiotics have become the cornerstone of contemporary medical advancements ever since penicillin was discovered. Antibiotic resistance developed among germs quickly, placing a strain in the medical field. Methicillin-resistant Staphylococcus aureus (MRSA), Since 1961, has emerged as the major general antimicrobial resistant bacteria (AMR) worldwide. MRSA can easily transmit across the hospital system and has mostly gained resistance to medications called beta-lactamases. This enzyme destroys the cell wall of beta-lactam antibiotics resulting in resistance against that respective antibiotic. Daptomycin, linezolid and vancomycin were previously used to treat MRSA infections. However, due to mutations and Single nucleotide polymorphisms (SNPs) in Open reading frames (ORFs) and SCCmec machinery of respective antibody, MRSA developed resistance against those antibiotics. The MRSA strains (USA300, CC398, CC130 etc.), when their pan-genomes were analyzed were found the genes involved in invoking resistance against the antibiotics as well as the epidemiology of that respective strain. PENC (penicillin plus potassium clavulanate) is the new antibiotic showing potential in treatment of MRSA though it is itself resistant against penicillin alone. In this review, our main focus is on mechanism of development of AMR in MRSA, how different ORFs are involved in evoking resistance in MRSA and what is the core-genome of different antimicrobial resistant MRSA.

Discovery of Novel Resistance Mechanisms of Vibrio parahaemolyticus Biofilm against Aminoglycoside Antibiotics

Inappropriate use of antibiotics eventually leads to the emergence of antibiotic-resistant strains and invalidates the treatment of infectious diseases. Aminoglycoside antibiotics (AGAs) are a class of broad-spectrum cationic antibiotics widely used for the treatment of Gram-negative bacterial infections. Understanding the AGA resistance mechanism of bacteria would increase the efficacy of treating these infections. This study demonstrates a significant correlation between AGA resistance and the adaptation of biofilms by Vibrio parahaemolyticus (VP). These adaptations were the result of challenges against the aminoglycosides (amikacin and gentamicin). Confocal laser scanning microscope (CLSM) analysis revealed an enclosure type mechanism where the biological volume (BV) and average thickness (AT) of V. parahaemolyticus biofilm were significantly positively correlated with amikacin resistance (BIC) (p < 0.01). A neutralization type mechanism was mediated by anionic extracellular polymeric substances (EPSs). The biofilm minimum inhibitory concentrations of amikacin and gentamicin were reduced from 32 µg/mL to 16 µg/mL and from 16 µg/mL to 4 µg/mL, respectively, after anionic EPS treatment with DNase I and proteinase K. Here, anionic EPSs bind cationic AGAs to develop antibiotic resistance. Transcriptomic sequencing revealed a regulatory type mechanism, where antibiotic resistance associated genes were significantly upregulated in biofilm producing V. parahaemolyticus when compared with planktonic cells. The three mechanistic strategies of developing resistance demonstrate that selective and judicious use of new antibiotics are needed to win the battle against infectious disease.

Point Prevalence Survey of Antimicrobial Use during the COVID-19 Pandemic among Different Hospitals in Pakistan: Findings and Implications

The COVID-19 pandemic has significantly influenced antimicrobial use in hospitals, raising concerns regarding increased antimicrobial resistance (AMR) through their overuse. The objective of this study was to assess patterns of antimicrobial prescribing during the current COVID-19 pandemic among hospitals in Pakistan, including the prevalence of COVID-19. A point prevalence survey (PPS) was performed among 11 different hospitals from November 2020 to January 2021. The study included all hospitalized patients receiving an antibiotic on the day of the PPS. The Global-PPS web-based application was used for data entry and analysis. Out of 1024 hospitalized patients, 662 (64.64%) received antimicrobials. The top three most common indications for antimicrobial use were pneumonia (13.3%), central nervous system infections (10.4%) and gastrointestinal indications (10.4%). Ceftriaxone (26.6%), metronidazole (9.7%) and vancomycin (7.9%) were the top three most commonly prescribed antimicrobials among surveyed patients, with the majority of antibiotics administered empirically (97.9%). Most antimicrobials for surgical prophylaxis were given for more than one day, which is a concern. Overall, a high percentage of antimicrobial use, including broad-spectrums, was seen among the different hospitals in Pakistan during the current COVID-19 pandemic. Multifaceted interventions are needed to enhance rational antimicrobial prescribing including limiting their prescribing post-operatively for surgical prophylaxis.

Tricyclic Fused Lactams by Mukaiyama Cyclisation of Phthalimides and Evaluation of their Biological Activity

We report that phthalimides may be cyclized using a Mukaiyama-type aldol coupling to give variously substituted fused lactam (1,2,3,9b-tetrahydro-5H-pyrrolo[2,1-a]isoindol-5-one) systems. This novel process shows a high level of regioselectivity for o-substituted phthalimides, dictated by steric and electronic factors, but not for m-substituted phthalimides. The initial aldol adduct is prone to elimination, giving 2,3-dihydro-5H-pyrrolo[2,1-a]isoindol-5-ones, and the initial cyclisation can be conducted in such a way that aldol cyclisation-elimination is achievable in a one-pot approach. The 2,3-dihydro-5H-pyrrolo[2,1-a]isoindol-5-ones possess cross conjugation and steric effects which significantly influence the reactivity of several functional groups, but conditions suitable for epoxidation, ester hydrolysis and amide formation, and reduction, which provide for ring manipulation, were identified. Many of the derived lactam systems, and especially the eliminated systems, show low solubility, which compromises biological activity, although in some cases, antibacterial and cytotoxic activity was found, and this new class of small molecule provides a useful skeleton for further elaboration and study.

Short- and Long-Term Effects of Different Antibiotics on the Gut Microbiota and Cytokines Level in Mice

BACKGROUND

Antibiotics are the first line of treatment for infectious diseases. However, their overuse can increase the spread of drug-resistant bacteria. The present study analyzed the impact of different types of antibiotics on the gut microbiome and cytokines level of mice.

METHODS

A total of five groups of 8-week-old male BALB/c mice (n = 35) were treated with piperacillin-tazobactam (TZP), ceftriaxone (CRO), tigecycline (TGC), levofloxacin (LEV) or normal saline (Ctrl), respectively, for up to 4 weeks. Fecal samples were analyzed by bacterial 16S rRNA gene sequencing for bacterial identification. Blood samples were used for the determination of 23 serum cytokines using multiplex immunoassay.

RESULTS

Exposure to antibiotics was shown to affect the normal weight gain of mice. Significant changes in gut composition caused by TZP, CRO and TGC treatment included the decreased abundance of Bacteroidetes (p < 0.01), Muribaculaceae (p < 0.01) and Lachnospiraceae (p < 0.01), and the increased abundance of Proteobacteria (p < 0.05), Enterobacteriaceae (including Klebsiella and Enterobacter) (p < 0.01) and Enterococcaceae (including Enterococcus) (p < 0.01). After 4-week treatment, the TZP, CRO and LEV groups had significantly lower concentrations of several serum cytokines. Correlation analysis of the top 30 bacterial genera and cytokines showed that Enterococcus and Klebsiella were strongly positively correlated with tumor necrosis factor-α (TNF-α), interleukins (IL) IL-12p70 and IL-1β. Desulfovibrio, Candidatus Saccharimonas, norank_f__norank_o__Clostridia_UCG-014, Lactobacillus, and Roseburia were strongly negatively correlated with these cytokines.

CONCLUSION

This study demonstrates the effects of various antibiotics on the intestinal microflora and immune status of mice. Compared with TZP, CRO and TGC, LEV had minimal impact on the gut microbiota. In addition to TGC, long-term TZP, CRO and LEV intervention can lead to a decrease in serum cytokine levels, which may depend on the intestinal microflora, antibiotic used and the duration of treatment.

Hipertensión arterial y riesgo cardiovascular

Introducción: la hipertensión arterial es una de las principales enfermedades a nivel mundial y constituye una importante causa de morbilidad y mortalidad para países de bajos y medianos ingresos. Objetivo: determinar la importancia epidemiológica de la hipertensión arterial como factor de riesgo cardiovascular en diferentes estudios realizados a nivel mundial, en Latinoamérica y Colombia. Metodología: se realizó una búsqueda de la literatura científica en las bases de datos de PudMed/Medline, Scielo, LILACS, así como también en revistas médicas y textos publicados por el Ministerio de Salud y Protección Social de Colombia. Discusión y conclusiones: más de 90% de los pacientes hipertensos padecen la forma primaria de la enfermedad, la cual está asociada con un aumento de la resistencia vascular periférica. Las características socioeconómicas de los países y el nivel educativo individual se relacionan con la prevalencia y el manejo adecuado de esta patología. El aumento en la prevalencia de las enfermedades crónicas, sumado a eventos históricos de importancia, fueron determinantes para el desarrollo de estudios epidemiológicos mundiales como el Framingham Heart Study. En América Latina y en Colombia se han realizado diferentes estudios que permiten establecer datos relacionados con la hipertensión arterial, demostrando cifras alarmantes en cuanto al conocimiento, tratamiento y control de esta condición, por lo cual, surge la necesidad de establecer programas para la detección de pacientes hipertensos con el fin de generar estrategias que disminuyan de manera significativa las enfermedades cardiovasculares.

Synthesis and evaluation of novel furanones as biofilm inhibitors in opportunistic human pathogens

Diseases caused by biofilm-forming pathogens are becoming increasingly prevalent and represent a major threat to human health. This trend has prompted a search for novel inhibitors of microbial biofilms which could, for example, be used to potentiate existing antibiotics. Naturally-occurring, halogenated furanones isolated from marine algae have proven to be effective biofilm inhibitors in several bacterial species. In this work, we report the synthesis of a library of novel furanones and their subsequent evaluation as biofilm inhibitors in several opportunistic human pathogens including S. enterica, S. aureus, E. coli, S. maltophilia, P. aeruginosa and C. albicans. A number of the most potent compounds were subjected to further analysis by confocal laser-scanning microscopy for their effects on P. aeruginosa and C. albicans biofilms individually, in addition to mixed polymicrobial biofilms. Lastly, we investigated the impact of a promising candidate on survival rates in vivo using a Galleria mellonella model.

Construction of Electrochemical Sensors for Antibiotic Detection Based on Carbon Nanocomposites

Excessive antibiotic residues in food can cause detrimental effects on human health. The establishment of rapid, sensitive, selective, and reliable methods for the detection of antibiotics is highly in demand. With the inherent advantages of high sensitivity, rapid analysis time, and facile miniaturization, the electrochemical sensors have great potential in the detection of antibiotics. The electrochemical platforms comprising carbon nanomaterials (CNMs) have been proposed to detect antibiotic residues. Notably, with the introduction of functional CNMs, the performance of electrochemical sensors can be bolstered. This review first presents the significance of functional CNMs in the detection of antibiotics. Subsequently, we provide an overview of the applications for detection by enhancing the electrochemical behaviour of the antibiotic, as well as a brief overview of the application of recognition elements to detect antibiotics. Finally, the trend and the current challenges of electrochemical sensors based on CNMs in the detection of antibiotics is outlined.

Covalent Proteomimetic Inhibitor of the Bacterial FtsQB Divisome Complex

The use of antibiotics is threatened by the emergence and spread of multidrug-resistant strains of bacteria. Thus, there is a need to develop antibiotics that address new targets. In this respect, the bacterial divisome, a multi-protein complex central to cell division, represents a potentially attractive target. Of particular interest is the FtsQB subcomplex that plays a decisive role in divisome assembly and peptidoglycan biogenesis in E. coli. Here, we report the structure-based design of a macrocyclic covalent inhibitor derived from a periplasmic region of FtsB that mediates its binding to FtsQ. The bioactive conformation of this motif was stabilized by a customized cross-link resulting in a tertiary structure mimetic with increased affinity for FtsQ. To increase activity, a covalent handle was incorporated, providing an inhibitor that impedes the interaction between FtsQ and FtsB irreversibly. The covalent inhibitor reduced the growth of an outer membrane-permeable E. coli strain, concurrent with the expected loss of FtsB localization, and also affected the infection of zebrafish larvae by a clinical E. coli strain. This first-in-class inhibitor of a divisome protein–protein interaction highlights the potential of proteomimetic molecules as inhibitors of challenging targets. In particular, the covalent mode-of-action can serve as an inspiration for future antibiotics that target protein–protein interactions.

Overcoming Methicillin-Resistance Staphylococcus aureus (MRSA) Using Antimicrobial Peptides-Silver Nanoparticles

Antibiotics are regarded as a miracle in the medical field as it prevents disease caused by pathogenic bacteria. Since the discovery of penicillin, antibiotics have become the foundation for modern medical discoveries. However, bacteria soon became resistant to antibiotics, which puts a burden on the healthcare system. Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most prominent antibiotic-resistant bacteria in the world since 1961. MRSA primarily developed resistance to beta-lactamases antibiotics and can be easily spread in the healthcare system. Thus, alternatives to combat MRSA are urgently required. Antimicrobial peptides (AMPs), an innate host immune agent and silver nanoparticles (AgNPs), are gaining interest as alternative treatments against MRSA. Both agents have broad-spectrum properties which are suitable candidates for controlling MRSA. Although both agents can exhibit antimicrobial effects independently, the combination of both can be synergistic and complementary to each other to exhibit stronger antimicrobial activity. The combination of AMPs and AgNPs also reduces their own weaknesses as their own, which can be developed as a potential agent to combat antibiotic resistance especially towards MRSA. Thus, this review aims to discuss the potential of antimicrobial peptides and silver nanoparticles towards controlling MRSA pathogen growth.

Photodegradable Antimicrobial Agents: Synthesis and Mechanism of Degradation

As a strategy to inactivate antimicrobial agents after use, we designed a range of ethanolamine derivatives where four of them possessed interesting activity. The ethanolamine moiety facilitates photodecomposition, which in a potential drug will take place after use. Herein, the synthetic preparation of these compounds and the mechanism of photoinactivation are described.

Self-assembly CuO-loaded nanocomposite involving functionalized DNA with dihydromyricetin for water-based efficient and controllable antibacterial action

With the antibiotic crisis intensifies, the defense and treatment of pathogen infections in safe and effective fashion has become a critical issue. Herein, we report a novel and advanced type of sterilization agent designed via the functionalization DNA nanocarriers based on dihydromyricetin and CuO-loaded nanoparticles (DNA/DMY-CuO). Firstly, a pure dihydromyricetin (DMY) isolated from Ampelopsis grossedentata is used as a bridge to the stimulate the construction of DNA cross-linking networks by hydrogen bonding. Subsequently, a 3D spherical CuO-loaded nanocomposite (204.39 nm) is customized using the DNA/DMY network as a biological template through a simple coordination-assisted self-assembly method, which exhibits a high dispersibility, water-solubility and physiological stability. The reversible physical interactions in nanocarriers allows the selective separation and automatic release of CuO NPs from DNA/DMY-CuO in neutral and wound exudate environments, thereby extending the survival period of CuO NPs by nearly 24 h. Meanwhile, the nanocarriers system relied on the strong binding ability of DMY to the outer membrane of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) achieves controlled drug delivery onto the pathogen wall. The advanced antibacterial action of DNA/DMY-CuO also reflected in membrane destruction, cytoplasmic constituent leakages and ATP synthetic pathway cessation, thereby halting cytosolic metalloregulatory mechanisms and minimizing drug-resistant bacteria. In summary, such multi-functional CuO-loaded nanocomposite provides a water-dispersibility, controllable, low cytotoxicity and long-effective platform to address the ever-growing threats of bacterial infections.

Bioengineered Probiotics: Synthetic Biology Can Provide Live Cell Therapeutics for the Treatment of Foodborne Diseases

The rising prevalence of antibiotic resistant microbial pathogens presents an ominous health and economic challenge to modern society. The discovery and large-scale development of antibiotic drugs in previous decades was transformational, providing cheap, effective treatment for what would previously have been a lethal infection. As microbial strains resistant to many or even all antibiotic drug treatments have evolved, there is an urgent need for new drugs or antimicrobial treatments to control these pathogens. The ability to sequence and mine the genomes of an increasing number of microbial strains from previously unexplored environments has the potential to identify new natural product antibiotic biosynthesis pathways. This coupled with the power of synthetic biology to generate new production chassis, biosensors and “weaponized” live cell therapeutics may provide new means to combat the rapidly evolving threat of drug resistant microbial pathogens. This review focuses on the application of synthetic biology to construct probiotic strains that have been endowed with functionalities allowing them to identify, compete with and in some cases kill microbial pathogens as well as stimulate host immunity. Weaponized probiotics may have the greatest potential for use against pathogens that infect the gastrointestinal tract: Vibrio cholerae, Staphylococcus aureus, Clostridium perfringens and Clostridioides difficile. The potential benefits of engineered probiotics are highlighted along with the challenges that must still be met before these intriguing and exciting new therapeutic tools can be widely deployed.

β-Lactam-Resistant Streptococcus pneumoniae Dynamics Following Treatment: A Dose-Response Meta-analysis

BACKGROUND

Patient exposure to antibiotics promotes the emergence of drug-resistant pathogens. The aim of this study was to identify whether the temporal dynamics of resistance emergence at the individual-patient level were predictable for specific pathogen-drug classes.

METHODS

Following a systematic review, a novel robust error meta-regression method for dose-response meta-analysis was used to estimate the odds ratio (OR) for carrying resistant bacteria during and following treatment compared to baseline. Probability density functions fitted to the resulting dose-response curves were then used to optimize the period during and/or after treatment when resistant pathogens were most likely to be identified.

RESULTS

Studies of Streptococcus pneumoniae treatment with β-lactam antibiotics demonstrated a peak in resistance prevalence among patients 4 days after completing treatment with a 3.32-fold increase in odds (95% confidence interval [CI], 1.71-6.46). Resistance waned more gradually than it emerged, returning to preexposure levels 1 month after treatment (OR, 0.98 [95% CI, .55-1.75]). Patient isolation during the peak dose-response period would be expected to reduce the risk that a transmitted pathogen is resistant equivalently to a 50% longer isolation window timed from the first day of treatment.

CONCLUSIONS

Predictable temporal dynamics of resistance levels have implications both for surveillance and control.

Acute and persistent effects of commonly used antibiotics on the gut microbiome and resistome in healthy adults

Antibiotics are deployed against bacterial pathogens, but their targeting of conserved microbial processes means they also collaterally perturb the commensal microbiome. To understand acute and persistent effects of antibiotics on the gut microbiota of healthy adult volunteers, we quantify microbiome dynamics before, during, and 6 months after exposure to 4 commonly used antibiotic regimens. We observe an acute decrease in species richness and culturable bacteria after antibiotics, with most healthy adult microbiomes returning to pre-treatment species richness after 2 months, but with an altered taxonomy, resistome, and metabolic output, as well as an increased antibiotic resistance burden. Azithromycin delays the recovery of species richness, resulting in greater compositional distance. A subset of volunteers experience a persistent reduction in microbiome diversity after antibiotics and share compositional similarities with patients hospitalized in intensive care units. These results improve our quantitative understanding of the impact of antibiotics on commensal microbiome dynamics, resilience, and recovery.

A molecularly imprinted polymer nanoparticle-based surface plasmon resonance sensor platform for antibiotic detection in river water and milk

Using a solid-phase molecular imprinting technique, high-affinity nanoparticles (nanoMIPs) selective for the target antibiotics, ciprofloxacin, moxifloxacin, and ofloxacin have been synthesised. These have been applied in the development of a surface plasmon resonance (SPR) sensor for the detection of the three antibiotics in both river water and milk. The particles produced demonstrated good uniformity with approximate sizes of 65.8 ± 1.8 nm, 76.3 ± 4.1 nm, and 85.7 ± 2.5 nm, and were demonstrated to have affinities of 36.2 nM, 54.7 nM, and 34.6 nM for the ciprofloxacin, moxifloxacin, and ofloxacin nanoMIPs, respectively. Cross-reactivity studies highlighted good selectivity towards the target antibiotic compared with a non-target antibiotic. Using spiked milk and river water samples, the nanoMIP-based SPR sensor offered comparable affinity with 66.8 nM, 33.4 nM, and 55.0 nM (milk) and 39.3 nM, 26.1 nM, and 42.7 nM (river water) for ciprofloxacin, moxifloxacin, and ofloxacin nanoMIPs, respectively, to that seen within a buffer standard. Estimated LODs for the three antibiotic targets in both milk and river water were low nM or below. The developed SPR sensor showed good potential for using the technology for the capture and detection of antibiotics from food and environmental samples.

Small molecules and their impact in drug discovery: A perspective on the occasion of the 125th anniversary of the Bayer Chemical Research Laboratory

The year 2021 marks the 125th anniversary of the Bayer Chemical Research Laboratory in Wuppertal, Germany. A significant number of prominent small-molecule drugs, from aspirin to Xarelto, have emerged from this research site. In this review, we shed light on historic cornerstones of small-molecule drug research, discussing current and future trends in drug discovery as well as providing a personal outlook on the future of drug research with a focus on small molecules.

Bugs on Drugs: A Drosophila melanogaster Gut Model to Study In Vivo Antibiotic Tolerance of E. coli

With an antibiotic crisis upon us, we need to boost antibiotic development and improve antibiotics’ efficacy. Crucial is knowing how to efficiently kill bacteria, especially in more complex in vivo conditions. Indeed, many bacteria harbor antibiotic-tolerant persisters, variants that survive exposure to our most potent antibiotics and catalyze resistance development. However, persistence is often only studied in vitro as we lack flexible in vivo models. Here, I explored the potential of using Drosophila melanogaster as a model for antimicrobial research, combining methods in Drosophila with microbiology techniques: assessing fly development and feeding, generating germ-free or bacteria-associated Drosophila and in situ microscopy. Adult flies tolerate antibiotics at high doses, although germ-free larvae show impaired development. Orally presented E. coli associates with Drosophila and mostly resides in the crop. E. coli shows an overall high antibiotic tolerance in vivo potentially resulting from heterogeneity in growth rates. The hipA7 high-persistence mutant displays an increased antibiotic survival while the expected low persistence of ΔrelAΔspoT and ΔrpoS mutants cannot be confirmed in vivo. In conclusion, a Drosophila model for in vivo antibiotic tolerance research shows high potential and offers a flexible system to test findings from in vitro assays in a broader, more complex condition.

Nanomedicine to fight infectious disease

The ubiquity and potency of antibiotics may give the false impression that infection is a solved problem. Unfortunately, even bacterial infections, the target of antibiotics, remain a major cause of illness and death. Several major unmet needs persist: biofilms, such as those on implanted hardware, largely resist antibiotics; the inflammatory host response to infection often produces more damage than the infection itself; and systemic antibiotics often decimate the gut microbiome, which can predispose to additional infections and even predispose to non-infectious diseases. Additionally, there is an increasing threat from multi-drug resistant microorganisms, though market forces may continue to inhibit innovation in this realm. These numerous unmet infection-related needs provide attractive goals for innovation of targeted drug delivery technologies, especially those of nanomedicine. Here we review several of those innovations in pre-clinical development, the two such therapies which have made it to clinical use, and the opportunities for further technology development for treating infections.

New Auranofin Analogs with Antibacterial Properties against Burkholderia Clinical Isolates

Bacteria of the genus Burkholderia include pathogenic Burkholderia mallei, Burkholderia pseudomallei and the Burkholderia cepacia complex (Bcc). These Gram-negative pathogens have intrinsic drug resistance, which makes treatment of infections difficult. Bcc affects individuals with cystic fibrosis (CF) and the species B. cenocepacia is associated with one of the worst clinical outcomes. Following the repurposing of auranofin as an antibacterial against Gram-positive bacteria, we previously synthetized auranofin analogs with activity against Gram-negatives. In this work, we show that two auranofin analogs, MS-40S and MS-40, have antibiotic activity against Burkholderia clinical isolates. The compounds are bactericidal against B. cenocepacia and kill stationary-phase cells and persisters without selecting for multistep resistance. Caenorhabditis elegans and Galleria mellonella tolerated high concentrations of MS-40S and MS-40, demonstrating that these compounds have low toxicity in these model organisms. In summary, we show that MS-40 and MS-40S have antimicrobial properties that warrant further investigations to determine their therapeutic potential against Burkholderia infections.

New Auranofin Analogs with Antibacterial Properties against Burkholderia Clinical Isolates

Bacteria of the genus Burkholderia include pathogenic Burkholderia mallei, Burkholderia pseudomallei and the Burkholderia cepacia complex (Bcc). These Gram-negative pathogens have intrinsic drug resistance, which makes treatment of infections difficult. Bcc affects individuals with cystic fibrosis (CF) and the species B. cenocepacia is associated with one of the worst clinical outcomes. Following the repurposing of auranofin as an antibacterial against Gram-positive bacteria, we previously synthetized auranofin analogs with activity against Gram-negatives. In this work, we show that two auranofin analogs, MS-40S and MS-40, have antibiotic activity against Burkholderia clinical isolates. The compounds are bactericidal against B. cenocepacia and kill stationary-phase cells and persisters without selecting for multistep resistance. Caenorhabditis elegans and Galleria mellonella tolerated high concentrations of MS-40S and MS-40, demonstrating that these compounds have low toxicity in these model organisms. In summary, we show that MS-40 and MS-40S have antimicrobial properties that warrant further investigations to determine their therapeutic potential against Burkholderia infections.

Antibiotic resistance in microbes: History, mechanisms, therapeutic strategies and future prospects

Antibiotics have been used to cure bacterial infections for more than 70 years, and these low-molecular-weight bioactive agents have also been used for a variety of other medicinal applications. In the battle against microbes, antibiotics have certainly been a blessing to human civilization by saving millions of lives. Globally, infections caused by multidrug-resistant (MDR) bacteria are on the rise. Antibiotics are being used to combat diversified bacterial infections. Synthetic biology techniques, in combination with molecular, functional genomic, and metagenomic studies of bacteria, plants, and even marine invertebrates are aimed at unlocking the world's natural products faster than previous methods of antibiotic discovery. There are currently only few viable remedies, potential preventive techniques, and a limited number of antibiotics, thereby necessitating the discovery of innovative medicinal approaches and antimicrobial therapies. MDR is also facilitated by biofilms, which makes infection control more complex. In this review, we have spotlighted comprehensively various aspects of antibiotics viz. overview of antibiotics era, mode of actions of antibiotics, development and mechanisms of antibiotic resistance in bacteria, and future strategies to fight the emerging antimicrobial resistant threat.

Using computers to ESKAPE the antibiotic resistance crisis

Since the discovery of penicillin, the development and use of antibiotics have promoted safe and effective control of bacterial infections. However, the number of antibiotic-resistance cases has been ever increasing over time. Thus, the drug discovery process demands fast, efficient and cost-effective alternative approaches for developing lead candidates with outstanding performance. Computational approaches are appealing techniques to develop lead candidates in an in silico fashion. In this review, we provide an overview of the implementation of current in silico state-of-the-art techniques, including machine learning (ML) and deep learning (DL), in drug discovery. We also discuss the development of quantum computing and its potential benefits for antibiotics research and current bottlenecks that limit computational drug discovery advancement.

Are Bacteriocins a Feasible Solution for Current Diverse Global Problems?

The development of effective technologies to cope with persistent and progressive global problems in the areas of human health and sustainable development has become an imperative worldwide challenge. The search for natural alternatives has led to the discovery of bacteriocins, which are potent protein antimicrobial compounds produced by most bacteria. The relevance of these molecules is evidenced by the more than 4,500 papers published in the last decade in Scopus index journals highlighting their versatility and potential to impact various aspects of daily life, including the food industry, medicine, and agriculture. Bacteriocins have demonstrated antibacterial, antifungal, antiviral, and anticancer activity, and they also act as microbiota regulators and plant growth promoters. This mini-review aims to provide insights into the current state and emerging roles of bacteriocins, as well as their potential and limitations as feasible solutions against current diverse global problems.

Photodegradable antimicrobial agents - synthesis, photodegradation, and biological evaluation

Multi-drug resistant (MDR) bacteria are already a significant health-care problem and are making the combat of infections quite challenging. Here we report the synthesis of several new compounds containing an ethanolamine moiety, of which two exhibit promising antimicrobial activity (at the 6 μM level). All the compounds are degraded when exposed to light and form inactive products.

Epidemiology of mobile colistin resistance (mcr) genes in aquatic environments

Colistin is one of the last-line therapies against multidrug-resistant Gram-negative pathogens, especially carbapenemase-producing isolates, making resistance to this compound a major global public-health crisis. Until recently, colistin resistance in Gram-negative bacteria was known to arise only by chromosomal mutations. However, a plasmid-mediated colistin resistance mechanism was described in late 2015. This mechanism is encoded by different mobile colistin resistance (mcr) genes that encode phosphoethanolamine (pEtN) transferases. These enzymes catalyse the addition of a pEtN moiety to lipid A in the bacterial outer membrane leading to colistin resistance. MCR-producing Gram-negative bacteria have been largely disseminated worldwide. However, their environmental dissemination has been underestimated. Indeed, water environments act as a connecting medium between different environments, allowing them to play a crucial role in the spread of antibiotic resistance between the natural environment and humans and other animals. For a better understanding of the role of such environments as reservoirs and/or dissemination routes of mcr genes, this review discusses primarily the various water habitats contributing to the spread of antibiotic resistance. Thereafter, we provide an overview of existing knowledge regarding the global epidemiology of mcr genes in water environments. This review confirms the global distribution of mcr genes in several water environments, including wastewater from different origins, surface water and tap water, making these environments reservoirs and dissemination routes of concern for this resistance mechanism.

Bacterial Outer Membrane Vesicles as a Versatile Tool in Vaccine Research and the Fight against Antimicrobial Resistance

Gram-negative bacteria include a number of pathogens that cause disease in humans and animals. Although antibiotics are still effective in treating a considerable range of infections caused by Gram-negative bacteria, the alarming increase of antimicrobial resistance (AMR) induced by excessive use of antibiotics has raised global concerns. Therefore, alternative strategies must be developed to prevent and treat bacterial infections and prevent the advent of a postantibiotic era. Vaccines, one of the greatest achievements in the history of medical science, hold extraordinary potential to prevent bacterial infections and thereby reduce the need for antibiotics. Novel bacterial vaccines are urgently needed, however, and outer membrane vesicles (OMVs), naturally produced by Gram-negative bacteria, represent a promising and versatile tool that can be employed as adjuvants, antigens, and delivery platforms in the development of vaccines against Gram-negative bacteria. Here, we provide an overview of the many roles OMVs can play in vaccine development and the mechanisms behind these applications. Methods to improve OMV yields and a comparison of different strategies for OMV isolation aiming at cost-effective production of OMV-based vaccines are also reviewed.

The multifaceted nature of antimicrobial peptides: current synthetic chemistry approaches and future directions

Bacterial infections caused by 'superbugs' are increasing globally, and conventional antibiotics are becoming less effective against these bacteria, such that we risk entering a post-antibiotic era. In recent years, antimicrobial peptides (AMPs) have gained significant attention for their clinical potential as a new class of antibiotics to combat antimicrobial resistance. In this review, we discuss several facets of AMPs including their diversity, physicochemical properties, mechanisms of action, and effects of environmental factors on these features. This review outlines various chemical synthetic strategies that have been applied to develop novel AMPs, including chemical modifications of existing peptides, semi-synthesis, and computer-aided design. We will also highlight novel AMP structures, including hybrids, antimicrobial dendrimers and polypeptides, peptidomimetics, and AMP-drug conjugates and consider recent developments in their chemical synthesis.

Computational Methods and Tools in Antimicrobial Peptide Research

The evolution of antibiotic-resistant bacteria is an ongoing and troubling development that has increased the number of diseases and infections that risk going untreated. There is an urgent need to develop alternative strategies and treatments to address this issue. One class of molecules that is attracting significant interest is that of antimicrobial peptides (AMPs). Their design and development has been aided considerably by the applications of molecular models, and we review these here. These methods include the use of tools to explore the relationships between their structures, dynamics, and functions and the increasing application of machine learning and molecular dynamics simulations. This review compiles resources such as AMP databases, AMP-related web servers, and commonly used techniques, together aimed at aiding researchers in the area toward complementing experimental studies with computational approaches.

Cupriferous Silver Peroxysulfite Superpyramids as a Universal and Long-Lasting Agent to Eradicate Multidrug-Resistant Bacteria and Promote Wound Healing

Because of the emergent evolution of multidrug-resistant (MDR) bacteria, resistance to traditional antibiotics has been increasingly causing public health concerns that it can rapidly overcome the development of antibacterial agents. Here, we demonstrated a facile electrodeposition method to prepare silver peroxysulfite (Ag₇O₈HSO₄, AOHS) superpyramids on band-aids with extraordinary antibacterial performance. The porous structure and the sharp apex of AOHS superpyramids could facilitate the release of high-valence silver ions, which possess highly efficient MDR bacteria-killing effect and keep long-term antibacterial activity (>99% killing efficiency, recycle at least 4 times) because of their superior destruction capability of the membrane of the bacteria. A layer of copper was further evaporated onto the AOHS pyramids decorated on a band-aid, which could promote wound tissue angiogenesis and prohibit bacterial infection simultaneously, and finally accelerate the healing process in MDR bacteria-infected wound in vivo. The simple and low-cost fabrication process, as well as the outstanding antibacterial performance, make AOHS pyramids have promising applications in bacterial infection and practical sterilization fields, especially toward multidrug-resistant bacteria.

Exploring new horizons in health care: A mechanistic review on the potential of Unani medicines in combating epidemics of infectious diseases

The 20th and 21st centuries have witnessed epidemics and pandemics of various infectious agents. The development of effective antimicrobials in the 20th century has been complemented with the emergence of resistant and mutant strains. In this context, we present a comprehensive overview of the preventive measures described in Unani medicine during epidemics. Unani medicine is a traditional medicine system included in the Indian Systems of Medicine. Unani medicine has an extensive description of epidemic infections and preventive and therapeutic measures for the same. Certain factors like environment, season, and geographical location of a place are known to determine the extent of infections, and their escalation to epidemics. Maintenance of general health, immune-stimulation, and disinfecting of the environment are advised as protective measures, for which many drugs are prescribed. In the case of illness, specific antimicrobial drugs of natural origin are prescribed. Herein we discuss these measures in detail, along with the scientific evidences of anti-microbial, immunomodulatory, and health-protective actions of these drugs.