Antibiotic resistance

Multiplexed and highly sensitive FRET aptasensor for simultaneous assay of multiple antibiotics via DNAzyme and catalytic strand displacement amplification cascades

BACKGROUND

The emergence of antibiotic-resistant microorganisms poses significant risks to public health. Therefore, the development of technologies capable of detecting antibiotics with high sensitivity and selectivity is essential for monitoring and controlling the spread of antibiotic resistance. Yet, current major available antibody-based antibiotic detection methods often face limitations in sensitivity, complexity, and cost, and commonly one target antibiotic can be detected in one assay.

RESULTS

On the basis of a three-way DNA junction (3-WJ) signal construct, we describe a multiplexed fluorescence resonance energy transfer (FRET) aptasensor strategy for highly sensitive simultaneous detection of sarafloxacin (SAR) and enrofloxacin (ENR) through cyclic DNAzyme and catalytic strand displacement reaction (CSDR) signal amplification cascades. Target antibiotics are recognized separately by the aptamers in DNAzyme/apamer duplexes to release active DNAzyme sequences, which cleave the dumbbell substrate hairpins to free ssDNAs to trigger subsequent CSDR between the assistance hairpins and the 3-WJ constructs for formation of many fluorophores 5-carboxyfluorescein (FAM)- and 2',7'-dimethoxy-4', 5'-dichloro-6-carboxyfluorescein (JOE)/6-carboxy-X-rhodamine (ROX)-labeled DNA duplexes. This leads to the pulling of FAM dye donor in proximity to the ROX and JOE dye acceptors, facilitating the yield of considerably amplified FRET signals at 555 nm and 605 nm for the SAR and ENR assays, respectively, with detection limits of 1.95 pM (0.76 ng/L) and 5.01 pM (1.8 ng/L) within 2.5 h. Additionally, this sensing method can selectively discriminate SAR and ENR against non-target antibiotics and has been validated for the simultaneous detection of SAR and ENR in milk samples.

SIGNIFICANCE

Featured with the advantages of convenient and significant signal amplification capability as well as single excitation for multiplexed detection, the successful demonstration of our method for sensitive and simultaneous detection of two antibiotics therefore shows its promising potential for constructing different multiplexed aptasensors for detecting various low levels of biomolecules.

Antimicrobial and Potent Anti-Biofilm Properties of Rationally Designed α-Helix Antimicrobial Peptides

The antimicrobial resistance (AMR) crisis represents a significant global threat. Unlike traditional antibiotics, antimicrobial peptides offer a promising pathway because of their primary mechanisms. This study aimed to evaluate and rationally design novel AMPs based on tobacco nectar's AMP (Pep 6) to combat antibiotic resistance issues. Substitution and truncation of some amino acids were applied. Four peptides, KF19, KF16, LK16, and LR16, were designed with enhanced net charge hydrophobicity. They were evaluated for their in vitro antibacterial activity. However, only promising AMPs were further evaluated for their hemolytic activity, time-killing kinetics, mode of action, and anti-biofilm properties. The results showed that only KF19 and LR16 have potent activity against Staphylococcus aureus ATCC25923 and resistant isolates with MIC values from 7.81 to 15.62 μg/mL. Hemolysis ratios were 2.38% and 2.24% at 125 μg/mL for KF19 and LR16, respectively. Both peptides were able to kill S. aureus ATCC25923 within 2 h. SEM results showed their ability to target the cell membrane. Both peptides destroyed the S. aureus biofilms significantly at 62.5 and 125 μg/mL (**p < 0.01, ***p < 0.001, ****p < 0.0001). This study supported rational design in developing new antibacterial agents and demonstrated the therapeutic potency of novel peptides that could solve the resistance issues.

Probiotic Characterization of LAB isolated from Sourdough and Different Traditional Dairy Products Using Biochemical, Molecular and Computational Approaches

The aim of this study was to identify and isolate lactic acid bacteria (LAB) from indigenous sourdough and dairy samples in Iran, and to assess their probiotic properties in vitro. A total of 560 potential LAB isolates were examined, and 87 demonstrated high survival rates in artificial gastrointestinal fluids without hemolytic activity. The selected isolates exhibited significant auto-aggregation (18.35 to 79.42%) and co-aggregation abilities (20.16 to 71.26%). Additionally, the isolates displayed varying degrees of cell surface hydrophobicity (12.32 to 76.24%). Results indicated that 19 LAB isolates had cholesterol assimilation rates exceeding 30%. Moreover, forty strains tested negative for all twelve assessed pathogenic genes and exhibited good adhesion to human intestinal epithelial cells (13.47 to 49.12%). Furthermore, 24 isolates formed strong biofilms, 29 formed moderate biofilms, and 23 formed weak biofilms. Except for isolates ABRIIFBI-8, ABRIIFBI-16, ABRIIFBI-23, ABRIIFBI-43, ABRIIFBI-56, and ABRIIFBI-62, most isolates were capable of producing exopolysaccharides. Consequently, LAB strains naturally occurring in sourdough and traditional dairy samples were suggested as potential probiotic candidates for incorporation into functional foods.

Nanomaterial-based drug delivery systems in overcoming bacterial resistance: Current review

Antimicrobial resistance is one of the most serious contemporary global health concerns, threatening the effectiveness of existing antibiotics and resulting in morbidity, mortality, and economic burdens. This review examines the contribution of nanomaterial-based drug delivery systems to solving the problems associated with bacterial resistance and provides a thorough overview of their mechanisms of action, efficiency, and perspectives for the future. Owing to their unique physicochemical properties, nanomaterials reveal new ways of passing through the traditional mechanisms of bacterial defence connected to the permeability barrier of membranes, efflux pumps, and biofilm formation. This review addresses the different types of nanomaterials, including metallic nanoparticles, liposomes, and polymeric nanoparticles, in terms of their antimicrobial properties and modes of action. More emphasis has been placed on the critical discussion of recent studies on such active systems. Both in vitro and in vivo models are discussed, with particular attention paid to multidrug-resistant bacteria. This review begins by reviewing the urgency for antimicrobial resistance (AMR) by citing recent statistics, which indicate that the number of deaths and reasons for financial losses continue to increase. A background is then provided on the limitations of existing antibiotic therapies and the pressing need to develop innovative approaches. Nanomaterial-based drug delivery systems have been proposed as promising solutions because of their potential to improve drug solubility, stability, and targeted delivery, although side effects can also be mitigated. In addition to established knowledge, this review also covers ongoing debates on the continuous risks associated with the use of nanomaterials, such as toxicity and environmental impact. This discussion emphasizes the optimization of nanomaterial design to target specific bacteria, and rigorous clinical trials to establish safety and efficacy in humans. It concludes with reflections on the future directions of nanomaterial-based drug delivery systems in fighting AMR, underlining the need for an interdisciplinary approach, along with continuous research efforts to translate these promising technologies into clinical practice. As the fight against bacterial resistance reaches its peak, nanomaterials may be the key to developing next-generation antimicrobial therapies.

Pharmacophore modeling, 2D-QSAR, molecular docking and ADME studies for the discovery of inhibitors of PBP2a in MRSA

Methicillin-resistant Staphylococcus aureus (MRSA) is considered to be a worldwide threat to human health and the global spread of MRSA has been associated with the emergence of different types of infections and resultant selection pressure due to exposure to many antibiotics. In the current era characterized by incessant antibiotic resistance, assessment of multiple molecular targets represents notable therapeutic opportunities in the medical and pharmaceutical industry and can aid in the discovery of novel molecules that inhibit various receptors effectively to replace the current weak antimicrobial agents. Penicillin binding protein 2a (PBP2a) of MRSA is a major determinant of resistance to β-lactam antibiotics. The activity of PBP2a is not inhibited by β-lactam antibiotics, allowing the strain to survive in the presence of β-lactams leading to resistance to β-lactam antibiotics. The study aimed at identifying potential inhibitors of PBP2a receptor of MRSA through ligand-based pharmacophore modeling, 2D-QSAR, molecular docking, ADMET screening as well as molecular dynamic (MD) simulations. The study led to the development of a satisfactory, predictive and significant 2D-QSAR model for predicting anti-MRSA activity of compounds and also led to the identification of two molecules: C21H25N7O4S2 (ChEMBL30602) and C20H17NO6S (ChEMBL304837) with favorable pharmacophore features and ADME properties with potential to bind strongly to PBP2a receptor of MRSA. MD simulation analysis showed that the interactions of C20H17NO6S (ChEMBL304837) with PBP2a over 100 ns was more stable and similar to the interaction of ceftobiprole with PBP2a and may become potential drug candidate against MRSA which has developed a lot of resistance to current antibiotics.

Pioneering bactericidal efficacy with nitrogen doping and zinc oxide nanoparticle decoration on carbon nanosheets

The escalating prevalence of drug-resistant pathogens poses a significant threat to global health, contributing to elevated mortality rates and inflated healthcare expenses. To combat antibacterial resistance, carbon-based nanocomposites incorporating metal oxides have emerged as a promising solution in the development of advanced antibacterial agents. In this quest, we propose a nascent strategy to synthesize zinc oxide-decorated carbon nanosheets (ZnO@CNSn) via a co-precipitation method. The crystalline ZnO nanoparticles (ZnO-NPs) are homogeneously dispersed throughout a framework of melamine-enriched carbon nanosheets (CNSn). The presence of pyrrolic-N and pyridinic-N functionalities in ZnO@CNSn enhances the charge transfer kinetics and creates nucleation sites for uniform dispersion of ZnO-NPs, mitigating particle aggregation. Remarkably, XPS analysis reveals a distinct shift in peak intensity, characterized by a reduction in pyrrolic-N and a corresponding increase in pyridinic-N. This conversion of pyrrolic-N to pyridinic-N due to incorporation of ZnO-NPs onto CNSn plays a crucial role in improving its bactericidal effect. The antibacterial assays against Gram negative Escherichia coli, Gram positive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) confirm the bactericidal activity of ZnO@CNSn. Additionally, the SEM micrographs show altered bacterial morphology on interaction with the nanocomposites, further validating the effective bactericidal properties. Moreover, ZnO@CNSn exhibits enhanced cytocompatibility compared to CNSn. These findings underscore the promising potential of the ZnO-decorated CNSn architecture as a robust platform for advanced antibacterial applications.

Innovative antimicrobial lignins: Extraction and characterization for advanced hydrogel applications

The antioxidant and antimicrobial activities of lignin are often emphasized; however, not every type exhibits these properties. In this work, water-soluble fractions of alkali lignin (AL), poly-(caffeyl alcohol) lignin (PCFA), pyrolytic lignin (PL) and grape seed lignin (GSL) were prepared. The original and water-soluble lignin fractions were comprehensively characterized using high-resolution 2D NMR spectroscopy. Notably, water-soluble fractions of PCFA, PL and GSL lignins exhibited 3.6 to 3.9 higher antioxidant activities than the original lignins despite having a phenolic content of approximately 12 % to 55 % lower. Additionally, these fractions demonstrated antimicrobial activities against Micrococcus luteus, Serratia marcescens and Escherichia coli. The potential of water-soluble lignin fractions as active modifiers for physically crosslinked hydrogels was also investigated. Specifically, PL/F lignin served as an antioxidant and antimicrobial agent for modifying carrageenan without disrupting its viscoelastic and swelling behaviour. Carrageenan hydrogels with 6 % PL/F lignin showed an antioxidant activity of 219.6 mg TE g-1 hydrogel and reduction rates of 43.9 % against M. luteus, 31.6 % against S. marcescens and 20.6 % against E. coli.

Assessing diagnostic accuracy of congenital syphilis using penicillin administration data through the Pediatric Health Information System (PHIS) database

BackgroundGiven the most recent report of the nationwide rise of congenital syphilis (CS), with over a 773% increase from 2012 to 2021 per the Center for Disease Control and Prevention, we sought to utilize penicillin administration and ICD-10 billing data as proxies to assess the accuracy of diagnosis of congenital syphilis among major tertiary care pediatric hospitals.MethodsThis retrospective cohort study drawing data from 49 major tertiary children's hospitals in the United States sought to determine whether administration of penicillin in infants 30 days or younger, excluding other common infectious diseases treated with the medication, correlated with recently reported congenital syphilis epidemiologic data.Results2290 infants met inclusion criteria and received penicillin therapy, excluding infants with the most common secondary infections treated with penicillin, with 1123 (49.3%) of those included not having a syphilis diagnosis made. Of the neonates with a coded diagnosis of CS, (1107/1162) 95.3% received more than 1 day of penicillin therapy, and those not coded for CS that received more than 1 day of penicillin therapy was 37.9% (428/1128).ConclusionsOur findings found a significant number of infants who had penicillin administration and laboratory and procedural workup performed suggestive of congenital syphilis consideration, without a congenital syphilis diagnosis billed. This may reflect an underestimation of what is notably a growing nationwide pandemic. By addressing the screening and treatment needs of patients with CS, we can help to address some of the socioeconomic inequities in pediatric and maternal healthcare, and further accurately characterize the extent of this increasingly prevalent disease process.

Medicinal plants: bioactive compounds, biological activities, combating multidrug-resistant microorganisms, and human health benefits - a comprehensive review

In recent years, medicinal plants have gained significant attention in modern medicine due to their accessibility, affordability, widespread acceptance, and safety, making herbal remedies highly valued globally. Consequently, ensuring medicinal plants' quality, efficacy, and safety has become a critical concern for developed and developing nations. The emergence of multidrug-resistant microorganisms poses a serious global health threat, particularly in low-income regions, despite significant advancements in antimicrobial drugs and medical research over the past century. The rapid spread of these multidrug-resistant infections is primarily attributed to improper prescriptions, overuse, and unregulated access to antibiotics. Addressing these challenges, the standardization of plant-derived pharmaceuticals could pave the way for a transformative era in healthcare. Preserving and leveraging the historical knowledge of medicinal plants is essential before such valuable information is lost. Recently, there has been growing interest among natural and pharmaceutical scientists in exploring medicinal plants as potential sources of antimicrobial agents. This current review aims to identify the most common pathogens threatening human health, analyze the factors contributing to the rise of drug-resistant microorganisms, and evaluate the widespread use of medicinal plants across various countries as alternative antibiotics, highlighting their unique mechanisms of antimicrobial resistance.

Synergistic Antibacterial Effects of Plant Extracts and Essential Oils Against Drug-Resistant Bacteria of Clinical Interest

Infectious diseases, the second leading cause of death worldwide, have traditionally been treated with antimicrobials. However, the emergence of drug-resistant microorganisms has driven the need for alternative therapies. This study aimed to assess the antibacterial efficacy of Capparis spinosa crude extracts and five essential oils (EOs) derived from Salvia officinalis, Eucalyptus globulus, Micromeria barbata, Origanum vulgare, and Juniperus excelsa. The EOs were extracted using hydro-distillation, and C. spinosa extracts were obtained using ethanol and acetone solvents. Microdilution assays revealed that O. vulgare EO exhibited the strongest activity against Listeria monocytogenes, Escherichia coli, Salmonella spp., and Brucella melitensis, while C. spinosa demonstrated significant antibacterial effects against L. monocytogenes and notable inhibition of Pseudomonas aeruginosa. The combination of EOs with antibiotics, including M. barbata, J. excelsa, S. officinalis, and E. globulus, enhanced the efficacy of the antibiotics against recalcitrant bacterial strains. The synergistic effects were evaluated through Fractional Inhibitory Concentration Index (FICI) analysis. These findings confirm that the antibacterial efficacy observed in the tested EOs, especially when used in synergy with antibiotics, offers a promising therapeutic strategy to combat antimicrobial resistance.

Antimicrobial peptides in Clarias batrachus epidermal mucus: Characterization and therapeutic potential

The COVID-19 pandemic has accelerated global antibiotic usage, contributing to the rise of antimicrobial-resistant pathogens. Fish, as key players in aquatic ecosystems, have evolved unique defense mechanisms, including the secretion of antimicrobial compounds in their epidermal mucus, these antimicrobials could be used to treat antimicrobial-resistant pathogens. This study investigates the antimicrobial potential of acidic extracts from the epidermal mucus of Clarias batrachus against clinically significant pathogens. The extract demonstrated significant inhibitory effects against seven selected human pathogenic and opportunistic microbes. The antimicrobial mechanism was explored using field emission scanning electron microscopy (FESEM), revealing structural damage to the microbial cells. The physicochemical stability of the mucus compounds was experimentally validated under various conditions. Protein characterization through SDS-PAGE identified prominent bands at 11 kDa, corresponding to hemoglobin subunit-like chains (α and β), as confirmed by LC-MS/MS analysis. Bioinformatic evaluations suggested that these peptides possess not only antimicrobial but also potential antiviral and anticancer activities. Molecular docking studies further supported the applicability of these peptides against antibiotic-resistant targets (erm proteins), including NDM superbugs, highlighting their potential as novel therapeutic agents. This research underlines the promise of fish mucus-derived compounds in combating antimicrobial resistance, offering a natural and sustainable alternative to conventional antibiotics for both fish and human pathogens.

Therapeutic Efficacy of Ultraviolet C Light on Fungal Keratitis-In Vitro and Ex Vivo Studies

Objective: Fungal corneal infections are challenging to treat due to delayed diagnostic procedures, bacterial co-infections, and limited antifungal efficacy. This study investigates the therapeutic potential of ultraviolet C (UVC) light alone and combined with antifungal drugs. Methods: A subsurface infection model was developed in semi-solid agar droplets, with Candida albicans cells or Aspergillus brasiliensis spores inoculated into 0.75% w/v yeast peptone dextrose (YPD) agar in a 96-well microplate (5 µL per well). Two treatment groups were tested: (1) UVC exposure (265 nm, 1.93 mW/cm2) for durations of 0 s, 5 s, 10 s, 15 s, 30 s, 60 s, or 120 s, and (2) UVC combined with antifungal drugs (Amphotericin B and Natamycin) at their minimum inhibitory concentrations (MICs), determined in YPD broth. After treatment, agar droplets were homogenized, diluted, and plated for microbial enumeration. The most effective UVC doses were further tested in an ex vivo C. albicans porcine keratitis model, where the corneal epithelium was debrided, infected with C. albicans, and exposed to UVC. Corneas were then homogenized and plated to evaluate treatment efficacy. Results: UVC exposure of ≥15 s inhibited C. albicans, and ≥10 s inhibited A. brasiliensis (all p < 0.05). The broth MICs were 0.1875 µg/mL for Amphotericin B against C. albicans, 6.25 µg/mL against A. brasiliensis, and 0.78125 µg/mL for Natamycin against C. albicans, 7.8125 µg/mL against A. brasiliensis. The broth MIC did not eradicate fungi in the subsurface model. Combined treatments enhanced inhibition (all p < 0.05), with 30 s UVC + amphotericin B for C. albicans (p = 0.0218) and 30 s UVC + natamycin for A. brasiliensis (p = 0.0017). Ex vivo, 15 s and 30 s UVC inhibited growth (p = 0.0476), but no differences were seen between groups (all p > 0.05). Conclusion: UVC demonstrated strong antifungal efficacy, with supplementary benefits from combining UVC with low doses of antifungal drugs.

Vitamin B6 resensitizes mcr-carrying Gram-negative bacteria to colistin

Antimicrobial resistance poses a severe threat to human health, with colistin serving as a critical medication in clinical trials against multidrug-resistant Gram-negative bacteria. However, the efficacy of colistin is increasingly compromised due to the rise of MCR-positive bacteria worldwide. Here, we reveal a notable metabolic disparity between mcr-positive and -negative bacteria through transcriptome and metabolomics analysis. Specifically, pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, was significantly diminished in mcr-positive bacteria. Conversely, supplementing with PLP could reverse the metabolic profile of drug-resistant bacteria and effectively restore colistin's bactericidal properties. Mechanistically, PLP was found to augment bacterial proton motive force by inhibiting the Kdp transport system, a bacterial K+ transport ATPase, thereby facilitating the binding of the positively charged colistin to the negatively charged bacterial membrane components. Furthermore, PLP supplementation triggers ferroptosis-like death by accumulating ferrous ions and inducing lipid peroxidation. These two modes of action collectively resensitize mcr-harboring Gram-negative bacteria to colistin therapy. Altogether, our study provides a novel metabolic-driven antibiotic sensitization strategy to tackle antibiotic resistance and identifies a potentially safe antibiotic synergist.

Bioaccumulation of Pharmaceutically Active Compounds from Treated Urban Wastewaters in Aquatic Insect Larvae and Aerial Adults

The bioaccumulation of 80 pharmaceutically active compounds (PhACs) was examined in larvae, pupae, and (sub)adults of three groups of aquatic insects (caddisflies Oligotricha striata and Limnephilus spp. and mayfly Siphlonurus aestivalis) reared in laboratory conditions, with their larvae exposed to a treated urban wastewater for up to 3 months and fed with uncontaminated food. The probability of PhAC detection (above limits of quantification) in larvae was relatively constant throughout the exposure time, while in adults, it was lower at the beginning with a subsequent increase. The total concentration of detected PhACs was highest in larvae of Limnephilus spp. and lowest in larvae of S. aestivalis, decreasing similarly in the adults of all three species. Significant differences in the composition of PhACs with different levels of changes after emergence were detected between species. Only telmisartan was detected in all species and life stages. Sertraline and its active metabolite norsertraline exhibited significantly higher relative concentrations in caddisfly adults compared to larvae. Apart from the bioconcentration factor, increasing biodegradation half-life was the second-best predictor of increased PhAC concentration in adults compared to larvae. At the same time, log Kow, commonly associated with bioaccumulation, was not found to be a good predictor of this relationship. The present study provides valuable insights into the bioaccumulation patterns and potential transfer of PhACs from aquatic to terrestrial ecosystems.

Identification of antimicrobial peptides from the Ambystoma mexicanum displaying antibacterial and antitumor activity

Antibiotic resistance is a significant healthcare concern. Therefore, identifying target molecules that can serve as antibiotic substitutes is crucial. Among the promising candidates are antimicrobial peptides (AMPs). AMPs are defense mechanisms of the innate immune system which exist in almost all living organisms. Research on the AMPs of some amphibians has shown that, in addition to their antimicrobial effectiveness, AMPs also exhibit anti-inflammatory and anti-carcinogenic properties. In this study, we identify and characterize AMPs deriving from the skin mucus of the axolotl (Ambystoma mexicanum). Upon activity spectrum evaluation of the AMPs, we synthesized and ranked 22 AMPs according to antimicrobial efficacy by means of a prediction tool. To assess the AMPs' potential as antibacterial and anticarcinogenic compounds, we performed a minimum inhibitory concentration (MIC) assay for efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA), and an apoptosis assay on T-47D mammary carcinoma cells. We identified four AMPs that showed significant inhibition of MRSA, of which three also demonstrated anticarcinogenic activity. Gene expression analysis was performed on AMP-stimulated carcinoma cells using a breast cancer-specific RT-PCR array. In cells stimulated with the AMPs, gene expression analysis showed upregulation of tumor suppressor genes and downregulation of oncogenes. Overall, our work demonstrates the antimicrobial and anticarcinogenic activity of axolotl-derived AMPs. The results of this work serve as a basis to further investigate the mode of action and potential use of axolotl AMPs as therapeutic anticancer or antibiotic agents.

Detection, characterization, and antibiotic resistance profiling of multidrug-resistant bacteria isolated from circulating currency in the Northeastern region of Bangladesh

Objectives

The study aims to investigate the prevalence of multidrug resistant bacteria on paper and coin currency obtained from various occupational groups in Bangladesh and to identify the bacterial species present. The research further seeks to evaluate the antibiotic resistance patterns of the identified bacterial isolates.

Methods

84 paper currency notes and 56 coins were collected from seven different sources. Bacterial contamination was assessed using standard bacteriological and biochemical tests to identify and characterize the bacteria. Antibiotic susceptibility of the isolated strains was evaluated using an antibiogram study.

Results

A total of 368 bacterial isolates were detected across the sampled currency, with 99% of the currency samples contaminated by bacteria. Paper currency exhibited a higher prevalence of contamination compared to coins. Gram-staining revealed 20% Gram-positive and 80% Gram-negative bacteria on notes, compared to 38% Gram-positive and 62% Gram-negative bacteria on coins. Bacterial contamination was most frequent in samples from fish sellers, followed by poultry sellers, fruit sellers, and restaurants. The most commonly identified bacteria were Salmonella typhimurium, Staphylococcus aureus, Escherichia coli, and Klebsiella aerogenes. Antibiotic resistance testing revealed that all isolates were 100% resistant to amoxicillin, ampicillin, and penicillin G, while showing 100% sensitivity to azithromycin and gentamycin. Notably, 70.8% of the isolates were resistant to tetracycline, and 75% showed resistance to cefotaxime.

Conclusions

The widespread contamination of currency in Bangladesh with multidrug-resistant bacteria underscore the growing concern about antibiotic resistance. Preventative measures are essential to reduce cross-contamination between currency and food.

Novel Pyrrolidine-bearing quinoxaline inhibitors of DNA Gyrase, RNA polymerase and spike glycoprotein

Anti-infective agents are a class of drugs used to prevent, treat, or control infections caused by microorganisms such as bacteria, viruses, fungi, and parasites. They play a crucial role in modern medicine, helping to reduce the severity of infections and, in many cases, save lives. This study aims at the design and synthesis of hybrid compounds containing quinoxaline, pyrrolidine, and an azo bridge to combat antimicrobial resistance, and evaluating their antimicrobial, antifungal, and antiviral activities against various pathogenic strains. Eight most potent bactericidal derivatives 2, 4, 5, 7, 9, 11, 12, and 13 were further assessed for their antibiofilm activity. Additionally, these compounds were tested for their inhibitory effects on DNA gyrase using a DNA supercoiling assay with IC50 ranging from 26.57 to 84.84 μM when compared to ciprofloxacin as standard drug. The antiviral activities were performed against HSV-1, H1N1 and SARS-CoV-2 viruses, which showed that compound 9 has the highest antiviral activity with IC50 = 0.32 µM, IC50 = 1.76 µM and 1.06 µM, respectively, as well as the best safety profile with CC50 = 30000 µM. Compound 9 displayed the highest SI value against HSV-1, H1N1 and SARS-CoV-2 with values of 93685, 17,034 and 28368, respectively. Compound 9 inhibited RdRp and spike glycoprotein (IC50 = 2.437 ± 0.102 and 1425.1 ± 55.3 nM; respectively). The physicochemical and pharmacokinetic properties of the most active compounds were screened to identify those with optimal drug-like characteristics. Molecular docking studies were conducted on the most effective compounds to elucidate their binding interactions and mechanisms of action.

Mortality rates and risk factors associated with mortality in patients with stenotrophomonas maltophilia primary Bacteraemia and Pneumonia

This study aims to evaluate the risk factors associated with the mortality of S. maltophilia infections. Patients aged 18 years and older with S. maltophilia infection. Patients were divided into two groups primary bacteraemia and pneumonia. Of 176 S. maltophilia infections, 85 (48.2 %) were classified as bacteremia and 91 (51.8 %) as pneumonia. The mortality rate was 56 %, with no significant difference observed between the groups. Invasive mechanical ventilation, history of carbapenem use, and high Charlson Comorbidity Index (CCI) were significantly higher in the pneumonia group. In univariate analysis, higher Acute Physiology and Chronic Health Evaluation (APACHE) II score, higher Sequential Organ Failure Assessment (SOFA) score, and use of total parenteral nutrition (TPN) were identified as independent risk factors for 28-day mortality. This study demonstrates a mortality rate of 56 % in S. maltophilia infections and provides concrete data on risk factors for mortality.

Influence of SARS-CoV-2 infection on the use of ceftazidime-avibactam in the critical patient

OBJECTIVE

The objective of the study was to analyse possible changes in antibiotic policy with ceftazidime-avibactam during the SARS-CoV-2 pandemic in an Intensive Care Unit (ICU) to determine patient mortality 28 days after initiation of antimicrobial therapy and to describe the microorganisms that most frequently colonise critically ill patients.

MATERIAL AND METHOD

Observational, single-centre, cohort study that included patients on treatment with ceftazidime-avibactam in ICU between March 2020 and September 2021. Demographic (age, sex), microbiological (colonisation, microorganisms isolated in blood cultures), pharmacotherapeutic (duration of treatment with ceftazidime-avibactam, antimicrobials used in synergy with ceftazidime-avibactam) and clinical (mortality, length of hospital stay and comorbidities) variables were collected. As associated comorbidities, we identified how many of the patients included in the study had diabetes mellitus (DM), chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD) or obesity.

RESULTS

Eighty-nine patients were included, 85.39% of whom were male. Forty-nine patients were infected with Sars-CoV-2. Median ICU stay was 46 days (RIQ = 58-27) in SARS-CoV-2 infected and 34 days (RIQ = 51-24) in non-infected patients. Patients were on ceftazidime-avibactam treatment for a median of 8 days (RIQ = 13-4), being 7 days (RIQ = 11-2) in COVID-19 positive patients and 11 days (RIQ = 14-6) in COVID-19 negative patients (p > 0.05). Empirical treatment with ceftazidime-avibactam was started empirically in 41.57% (n = 37) of the patients. The percentage of empiric initiations in SARS-CoV-2 infected patients was 43% and in non-infected patients 40%, with no statistically significant difference between empiric initiation according to SARS-CoV-2 diagnostic status (p > 0.05). A total of 43.8% (n = 39) of the patients were colonised by a multidrug-resistant (MDR) bacterium. Regarding on the microorganisms that colonised patients had, the most frequent was Klebsiella pneumoniae, present in 66.6% of patients (n = 26 patients). Overall mortality was 41.6%, with no statistically significant differences between SARS-CoV-2 infected and non-infected patients (42.9% and 40%, respectively; p > 0.05).

CONCLUSION

The SARS-CoV-2 pandemic did not lead to a change in the criteria for the use of ceftazidime-avibactam in the critically ill patient.

Electrospun Nanofibers for the Delivery of Endolysin/Dendronized Ag-NPs Complex Against Pseudomonas aeruginosa

Purpose

As bacterial resistance to antibiotics increases, there is an urgent need to identify alternative antibacterial agents and improve antibacterial materials. One is the controlled transport of antibacterial agents that prevents infection with drug-resistant bacteria, especially in the treatment of difficult-to-heal wounds.

Methods

This work presents the use of electrospun PLCL/PVP (poly(L-lactide-co-ε-caprolactone/polyvinylpyrrolidone) nanofibers modified with two agents with antibacterial properties but with different mechanisms of action, that is, dendritic silver nanoparticles (Dend-AgNPs) and endolysin.

Results

The nanomat prepared in this manner showed significant antibacterial activity against antibiotic-resistant Pseudomonas aeruginosa strains, inhibiting their growth and production of key pigments and virulence factors. Moreover, the use of nanofibers as carriers of the selected factors significantly reduced their cytotoxicity towards human fibroblasts.

Conclusion

The results confirmed the possibility of using the presented product as an innovative dressing material, opening new perspectives for the treatment of wounds and combating bacterial infections with drug-resistant bacteria.

Plasma treated bimetallic nanofibers as sensitive SERS platform and deep learning model for detection and classification of antibiotics

Design of a sensitive, cost-effective SERS substrate is critical for probing analyte in trace concentration in real field environment. Present work reports the fabrication of an oxygen (O2) plasma treated bimetallic nanofibers as a sensitive SERS platform. In contrast to the conventional nanofiber-based SERS platform, the proposed plasma-treated bimetallic nanofibers-based SERS platform offers high sensitivity and reproducibility characteristics. On top, the use of bimetallic nanoparticles provides a synergistic effect, contributing to both electromagnetic and chemical enhancement to SERS performance and the plasma treatment contributes to the controlled exposure of the embedded nanoparticles (NPs) to the analyte thereby enhancing the overall sensitivity of the proposed technique. With standard Raman active probe molecules - 1,2-bis(4-pyridyl) ethylene (BPE) and rhodamine-6G (R6G) the limit of detection (LOD) and the limit of quantification (LOQ) of the proposed sensing platform are estimated to be 3.8 nM and 11.6 nM respectively. The enhancement factor (EF) of the designed sensing platform is calculated to be ∼108 with a maximum signal variations of 5 %. The applicability of the designed SERS substrate has been realized through detection of two antibiotics - fluconazole (FLU) and lincomycin (LIN) widely used in poultry farms. Furthermore, a deep learning model - artificial neural network (ANN) has been implemented for effective classification of the analyte molecules from a mixed sample.

A dissolving microneedle patch loaded with plumbagin/hydroxypropyl-β-cyclodextrin inclusion complex for infected wound healing

Treating infected wounds is facing a serious challenge due to the rapid spread of antibiotic resistance worldwide. In the search for novel antimicrobial drugs, natural products often serve as a crucial resource. Plumbagin (PLB) is the most important natural active ingredient in the root of Plumbago zeylanica L. known for its excellent antibacterial ability. However, the application of PLB is limited because of its poor water solubility, instability, and tendency to sublimate. In this study, we propose a solution by designing a hyaluronic acid (HA)/polyvinylpyrrolidone (PVP) dissolving microneedle patch loaded with PLB/hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex. PLB was encapsulated into the cavity of HP-β-CD to improve its solubility and stability using the neutralization agitation method. The formation of the inclusion complex significantly increased the water solubility of PLB to 1350 ± 6.8 μg/mL, which is 17 times higher than its original value of 79.3 ± 1.7 μg/mL. The encapsulation efficiency was found to be 94.82 ± 3.34 %. In vitro drug release studies, PLB microneedles loaded with PLB/HP-β-CD inclusion complex rapidly released into PBS within 15 min. Furthermore, the PLB microneedles exhibited strong antibacterial activity against Staphylococcus aureus (S. aureus) both in vivo and in vitro. They also remarkably accelerated the healing of infected wounds in mice by enhancing collagen deposition and re-epithelialization, reducing inflammation, and stimulating angiogenesis. Overall, this multifunctional microneedle patch shows promising potential for clinical applications in the healing of infected wounds.

Clinical Telavancin Failure in Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia

Telavancin is a fairly novel antibiotic derived from vancomycin developed to combat the constant evolutionary war against bacteria. It has achieved high clinical success in its role in treating Gram-positive organisms, although like in the case of any other antibiotics, failure can arise. The purpose of this article is to describe a case in which telavancin clinically failed in treating persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in a patient while describing the cause that led to telavancin failure.

Quinolone scaffolds as potential drug candidates against infectious microbes: a review

Prevalence of microbial infections and new rising pathogens are signified as causative agent for variety of serious and lethal health crisis in past years. Despite medical advances, bacterial and fungal infections continue to be a rising problem in the health care system. As more bacteria develop resistance to antibiotics used in therapy, and as more invasive microbial species develop resistance to conventional antimicrobial drugs. Relevant published publications from the last two decades, up to 2024, were systematically retrieved from the MEDLINE/PubMed, SCOPUS, EMBASE, and WOS databases using keywords such as quinolones, anti-infective, antibacterial, antimicrobial resistance and patents on quinolone derivatives. With an approach of considerable interest towards novel heterocyclic derivatives as novel anti-infective agents, researchers have explored these as essential tools in vistas of drug design and development. Among heterocycles, quinolones have been regarded extremely essential for the development of novel derivatives, even able to tackle the associated resistance issues. The quinolone scaffold with its bicyclic structure and specific functional groups such as the carbonyl and acidic groups, is indeed considered a valuable functionalities for further lead generation and optimization in drug discovery. Besides, the substitution at N-1, C-3 and C-7 positions also subjected to be having a significant role in anti-infective potential. In this article, we intend to highlight recent quinolone derivatives based on the SAR approach and anti-infective potential such as antibacterial, antifungal, antimalarial, antitubercular, antitrypanosomal and antiviral activities. Moreover, some recent patents granted on quinolone-containing derivatives as anti-infective agents have also been highlighted in tabular form. Due consideration of this, future research in this scaffold is expected to be useful for aspiring scientists to get pharmacologically significant leads.

Investigation of the antibacterial activity of Rhamnus cathartica L. and its anti-QS potential on Pseudomonas aeruginosa PAO1

The study aims to evaluate the Quorum Sensing (QS) system inhibition against some Gram-positive and Gram-negative bacteria detected by molecular modeling of R. cathartica L. plant extract. R. cathartica L. methanol extract was evaluated in vitro. R. cathartica L. extract was observed to have antimicrobial activity against Gram-positive and Gram-negative bacteria at different rates (11.3 mm-16 mm). The inhibitory effect of R. cathartica L. extract on P. aeruginosa PAO1 (elastase 61%, pyocyanin 18%, and biofilm 61%) was recorded moderately. Phytochemical analysis revealed that the main component of the extract is kaempferol. Therefore, the binding potential of kaempferol on QS system receptors was investigated via molecular docking. Computational analysis showed that kaempferol can inhibit the QS system by preventing competitive ligands from connecting to LasR. It may provide a new way to use R. cathartica L. seed extract as a green antibacterial agent.

Polyoxometalates and their composites for antimicrobial applications: Advances, mechanisms and future prospects

The overuse of antibiotics can lead to the development of antibiotic-resistant bacteria, which can be even more difficult to treat and pose an even greater threat to public health. In order to address the issue of antibiotic-resistant bacteria, researchers currently are exploring alternative methods of sterilization that are both effective and sustainable. Polyoxometalates (POMs), as emerging transition metal oxide compounds, exhibit significant potential in various applications due to their remarkable tunable physical and chemical performance, especially in antibacterial fields. They constitute a diverse family of inorganic clusters, characterized by a wide array of composition, structures and charges. Presently, several studies indicated that POM-based composites have garnered extensive attention in the realms of the antibacterial field and may become promising materials for future medical applications. Moreover, this review will focus on exploring the antibacterial properties and mechanisms of different kinds of organic-inorganic hybrid POMs, POM-based composites, films and hydrogels with substantial bioactivity, while POM-based composites have the dual advantages of POMs and other materials. Additionally, the potential antimicrobial mechanisms have also been discussed, mainly encompassing cell wall/membrane disruption, intracellular material leakage, heightened intracellular reactive oxygen species (ROS) levels, and depletion of glutathione (GSH). These findings open up exciting possibilities for POMs as exemplary materials in the antibacterial arena and expand their prospective applications.

A Comparison of Antibiotics' Resistance Patterns of E. coli and B. subtilis in their Biofilms and Planktonic Forms

BACKGROUND

A biofilm refers to a community of microbial cells that adhere to surfaces that are surrounded by an extracellular polymeric substance. Bacteria employ various defence mechanisms, including biofilm formation, to enhance their survival and resistance against antibiotics.

OBJECTIVE

The current study aims to investigate the resistance patterns of Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) in both biofilms and their planktonic forms.

METHODS

E. coli and B. subtilis were used to compare resistance patterns in biofilms versus planktonic forms of bacteria. An antibiotic disc diffusion test was performed to check the resistance pattern of biofilm and planktonic bacteria against different antibiotics such as penicillin G, streptomycin, and ampicillin. Biofilm formation and its validation were done by using quantitative (microtiter plate assay) and qualitative analysis (Congo red agar media).

RESULTS

A study of surface-association curves of E. coli and B. subtilis revealed that surface adhesion in biofilms was continuously constant as compared to their planktonic forms, thereby confirming the increased survival of bacteria in biofilms. Also, biofilms have shown high resistance towards the penicillin G, ampicillin and streptomycin as compared to their planktonic form.

CONCLUSION

It is safely inferred that E. coli and B. subtilis, in their biofilms, become increasingly resistant to penicillin G, ampicillin and streptomycin.

Distribution and ecological risks of pharmaceuticals and personal care products with different anthropogenic pressures in typical watersheds in China

Due to global population growth and increased healthcare accessibility, pharmaceuticals and personal care products (PPCPs) are closely linked with human activities and have become new pollutants alongside some legacy priority pollutants, such as polycyclic aromatic hydrocarbons (PAHs). Although PPCPs have been detected in numerous river basins in recent years, a few researches have been carried out on their association with human activities. In this paper, the concentrations of PPCPs and toxicological data were compiled for over 25 representative watersheds in China in the past two decades from various sources, including PubMed, Elsevier and Springer. Comprehensive analysis of the occurrence, spatial distribution, sources and ecological risk assessment was carried out for the 30 most frequently detected PPCPs in water environments. Multivariate statistical methods, including hierarchical cluster analysis (HCA), principal component analysis (PCA) and redundancy analysis (RDA), were employed to classify PPCPs and assess their relationship with human activities. The results indicated that the concentrations of PPCPs in rivers varied significantly across studied regions, ranging from non-detect to 21,885 ng/L. Many detected compounds in PPCPs were antibiotics and their occurrence was closely linked with the economic development, effectiveness of medicines and geographical location. Household emissions were identified as the primary contributor to the occurrence of PPCPs in river basins. A strong correlation has been observed between PPCPs level and socio-economic indicators from multivariate statistical analysis. Ecological risk assessment revealed that caffeine (CAF), ibuprofen (IBU) and anhydroerythromycin (ERY) pose the greatest threat to aquatic life, particularly in the Northern China. The data compiled in this study provide insights into the impacts of PPCPs and the relationship of their ecological risks with various human activities, particularly in the typical Chinese river basins. Our results are valuable for the effective management PPCPs.

Antimicrobial Resistance in the Context of Animal Production and Meat Products in Poland-A Critical Review and Future Perspective

The prevalence of antimicrobial-resistant bacteria in meat and meat products is a significant public health challenge, largely driven by the excessive and inappropriate use of antimicrobials in animal husbandry. In Poland, a key meat producer in Europe, antibiotic-resistant pathogens such as Campylobacter spp., Staphylococcus spp., Enterococcus spp., Listeria monocytogenes, and Enterobacterales have been detected in meat, posing serious risks to consumers. This review examines the use of antimicrobial agents in meat production and the resulting antimicrobial resistance (AMR) in microorganisms isolated from meat products in Poland. The mechanisms of AMR, genetic factors, and prevalence in Poland are presented. It highlights key factors contributing to AMR, such as antibiotic misuse in livestock farming, and discusses the legal regulations governing veterinary drug residues in food. This review emphasizes the importance of monitoring and enforcement to safeguard public health and calls for further research on AMR in the meat industry. Antimicrobial resistance in meat and meat products in Poland is a huge challenge, requiring stricter antibiotic controls in animal husbandry and improved surveillance systems. Additionally, the impact of husbandry practices on the environment and food requires further research. Future efforts should focus on nationwide monitoring, alternative strategies to reduce antibiotic use, and stronger enforcement to combat antimicrobial resistance and protect public health.

Increased risk of antibiotic resistance in surface water due to global warming

As the pace of global warming accelerates, so do the threats to human health, urgent priority among them being antibiotic-resistant infections. In the context of global warming, this review summarises the direct and indirect effects of rising surface water temperatures on the development of bacterial antibiotic resistance. First, the resistance of typical pathogens such as E. coli increased with average temperature. This is not only related to increased bacterial growth rate and horizontal gene transfer frequency at high temperatures but also heat shock responses and cumulative effects. Secondly, the acceleration of bacterial growth indirectly promotes antibiotic residues in surface water, which is conducive to the growth and spread of resistant bacteria. Furthermore, the cascading effects of global warming, including the release of nutrients into the water and the resulting increase of bacteria and algae, indirectly promote the improvement of resistance. Water treatment processes exposed to high temperatures also increase the risk of resistance in surface water. The fitness costs of antibiotic resistance under these dynamic conditions are also discussed, concluding the relationship between various factors and resistance persistence. It was expected to provide a comprehensive basis for mitigating antibiotic resistance in the face of global warming.

Antimicrobial activities of seasonally collected bee products: honey, propolis, royal jelly, venom, and mellitin

Ethanolic extracts of seasonally collected natural bee products (honey, propolis, royal jelly (RJ), and bee venom (BV)) were tested for their potential as antimicrobial agents against antibiotic-resistant bacteria and fungi. These extracts exhibited various inhibitory effects on antibiotic-resistant bacteria (Streptococcus pneumoniae, Staphylococcus aureus, MRSA, Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, and Haemophilus influenzae) and fungi (Aspergillus brasiliensis and Candida albicans), with the exception of S. pneumonia, which was not inhibited by honey and RJ extracts, and P. aeruginosa, which was not inhibited by RJ extracts. Interestingly, extracts of BV and its major content, melittin (MEL), displayed a wide spectrum of antimicrobial activity against all tested bacteria and fungi. This is the first study to show that propolis extract has bactericidal activity against S. pneumoniae and that BV extract and MEL have antibacterial activity against P. vulgaris, H. influenzae, and H. influenzae type b. Extracts of bee products collected in the spring generally exhibited the most significant antibacterial and antifungal activities. Based on total phenolic content (TPC) and total flavonoid content (TFC), it was found that spring samples of propolis, RJ, and honey, in that order, were the richest. Also, LC-MS-MS analysis of MEL content in BV demonstrated that it was the highest in spring sample. In terms of MIC and MBC values, Gram-positive bacteria were the most susceptible to bee products. First and foremost, the antimicrobial activity of bee products was ranked in descending order based on MIC values: BV, MEL, propolis, RJ, and honey.

SAMP: Identifying antimicrobial peptides by an ensemble learning model based on proportionalized split amino acid composition

It is projected that 10 million deaths could be attributed to drug-resistant bacteria infections in 2050. To address this concern, identifying new-generation antibiotics is an effective way. Antimicrobial peptides (AMPs), a class of innate immune effectors, have received significant attention for their capacity to eliminate drug-resistant pathogens, including viruses, bacteria, and fungi. Recent years have witnessed widespread applications of computational methods especially machine learning (ML) and deep learning (DL) for discovering AMPs. However, existing methods only use features including compositional, physiochemical, and structural properties of peptides, which cannot fully capture sequence information from AMPs. Here, we present SAMP, an ensemble random projection (RP) based computational model that leverages a new type of feature called proportionalized split amino acid composition (PSAAC) in addition to conventional sequence-based features for AMP prediction. With this new feature set, SAMP captures the residue patterns like sorting signals at both the N-terminal and the C-terminal, while also retaining the sequence order information from the middle peptide fragments. Benchmarking tests on different balanced and imbalanced datasets demonstrate that SAMP consistently outperforms existing state-of-the-art methods, such as iAMPpred and AMPScanner V2, in terms of accuracy, Matthews correlation coefficient (MCC), G-measure, and F1-score. In addition, by leveraging an ensemble RP architecture, SAMP is scalable to processing large-scale AMP identification with further performance improvement, compared to those models without RP. To facilitate the use of SAMP, we have developed a Python package that is freely available at https://github.com/wan-mlab/SAMP.

The challenge of antimicrobial resistance (AMR): current status and future prospects

Antimicrobial resistance (AMR) represents a critical global threat, compromising the effectiveness of antibacterial drugs as bacteria adapt and survive exposure to many classes of these drugs. This phenomenon is primarily fueled by the widespread overuse and misuse of antibacterial drugs, exerting selective pressure on bacteria and promoting the emergence of multi-resistant strains. AMR poses a top-priority challenge to public health due to its widespread epidemiological and economic implications, exacerbated not only by the diminishing effectiveness of currently available antimicrobial agents but also by the limited development of genuinely effective new molecules. In addressing this issue, our research aimed to examine the scientific literature narrating the Italian situation in the common European context of combating AMR. We sought to delineate the current state of AMR and explore future prospects through an analysis of strategies to counter antibacterial drug resistance. Adopting the "One Health" model, our objective was to comprehensively engage diverse sectors, integrate various disciplines, and propose programs, policies, and regulations. This narrative review, based on PubMed research related to antibiotic resistance, emphasizes the urgent need for a coordinated and proactive approach at both national and European levels to mitigate the impact of AMR and pave the way for effective strategies to counter this global health challenge.

Prevalence, Distribution and Antimicrobial Susceptibility of Enterobacteriaceae and Non-Fermenting Gram-Negative Bacilli Isolated From Environmental Samples in a Veterinary Clinical Hospital in Madrid, Spain

Managing infections caused by multidrug-resistant Gram-negative bacilli is a major public health concern, particularly in hospitals where surfaces can act as reservoirs for resistant microorganisms. Identifying these bacteria in hospital environments is crucial for improving healthcare safety. This study aimed to analyse environmental samples from a veterinary hospital to identify prevalent microorganisms and detect antimicrobial resistance patterns. A total of 183 surface samples were collected from 26 areas at the Veterinary Clinical Hospital of Alfonso X el Sabio University in Madrid. The isolated strains were identified, and susceptibility profiles were determined via the disk diffusion method. Clonality analysis was performed using pulsed-field gel electrophoresis. In total, 109 strains were isolated: 76.15% from the Enterobacteriaceae family and 23.85% non-fermenting Gram-negative bacilli. The isolates included Klebsiella, Enterobacter, Escherichia and Pseudomonas species, which could include high-risk clones, given their ability to carry several antimicrobial resistance genes. The equine area had the highest number of isolates (n = 71), accounting for 65% of the total. High resistance indices were observed against at least five of the 16 antibiotics tested, indicating significant multidrug resistance. Clonality analysis suggested potential cross-transmission within the facility. This study sampled hospital surfaces but not personnel or animals, making contamination sources unclear. Without resampling, the effectiveness of cleaning protocols remains uncertain. Results suggest that hospital staff play a key role in bacterial transmission. The lack of specialised preventive measures in veterinary hospitals highlights a need for further research and improvement.

Identification of cell wall binding domains and repeats in Streptococcus pneumoniae phage endolysins: A molecular and diversity analysis

Streptococcus pneumoniae (pneumococcus) is a multidrug-resistant pathogen associated with pneumonia, otitis media, meningitis and other severe complications that are currently a global threat to human health. The World Health Organization listed Pneumococcus as the fourth of twelve globally prioritized pathogens. Identifying alternatives to antibiotic therapies is urgently needed to combat Pneumococcus. Bacteriophage-derived endolysins can be used as alternative therapeutics due to their bacterial cell wall hydrolyzing capability. In this study, S. pneumoniae phage genomes were screened to create a database of endolysins for molecular modelling and diversity analysis of these lytic proteins. A total of 89 lytic proteins were curated from 81 phage genomes and categorized into eight groups corresponding to their different enzymatically active (EAD) domains and cell wall binding (CBDs) domains. We then constructed three-dimensional structures that provided insights into these endolysins. Group I, II, III, V, and VI endolysins showed conserved catalytic and ion-binding residues similar to existing endolysins available in the Protein Data Bank. While performing structural and sequence analysis with template lysin, an additional cell wall binding repeat was observed in Group II lysin, which was not previously known. Molecular docking performed with choline confirmed the existence of this additional repeat. Group III endolysins showed 99.16 % similarity to LysME-EF1, a lysin derived from Enterococcus faecalis. Furthermore, the comparative computational analysis revealed the existence of CBDs in Group III lysin. This study provides the first insight into the molecular and diversity analysis of S. pneumoniae phage endolysins that could be valuable for developing novel lysin-based therapeutics.

Precision medicine and patient outcomes in intensive care unit: Culture sensitivity, antibiotics, and APACHE score IV

BACKGROUND

In the intensive care unit (ICU), complex medical conditions require specialized care; the threat of antibiotic resistance is significant due to frequent antibiotic use. This study investigates the pivotal role of culture sensitivity testing in shaping antibiotic prescription practices and patient outcomes in ICUs.

MATERIALS AND METHODS

By using a prospective observational-analytical design, medical data from 640 patients at a Karachi hospital for one year in 2022 were utilized. The study focused on antibiotic therapy, including empiric and targeted approaches, culture sensitivity testing, the use of the APACHE scale for mortality prediction, and changes in antibiotic regimens based on culture reports. Statistical analysis involved Fisher's Exact and ANOVA tests.

RESULT

The age category above 60 emerged with the highest survivorship. Contrary to expectations, age did not seem to correlate significantly with mortality rates. Staphylococcus species was the most prevalent microorganism in this study, disproportionately affecting nonsurvivors 66.7%. The clinical profile comparison between survivors and nonsurvivors offered a multifaceted perspective, with significant differences in vital parameters such as temperature, heart rate, respiratory rate, urine output, FiO2, mean arterial pH, and blood sugar levels. Survivors (44.60%) underwent complete antibiotic regimen changes, a strategy for improved patient outcomes.

CONCLUSIONS

Complex antibiotic combinations were prescribed for broad clinical conditions. These insights pave the way for future research on antibiotic stewardship in ICUs, navigating more effective and targeted treatments.

Assessing the Reliability and Validity of a Questionnaire Evaluating Medical Students' Attitudes, Knowledge, and Perceptions of Antibiotic Education and Antimicrobial Resistance in University Training

The misuse and overuse of antibiotics represent a critical global issue and one of the most pressing public health challenges of the 21st century. Training future healthcare professionals effectively is essential for ensuring responsible antibiotic use. This study aimed to validate a questionnaire designed to evaluate the knowledge, attitudes, and perceptions of medical students regarding the education they receive on infectious diseases, antimicrobial resistance, and antibiotic stewardship during their university studies. Methods: A self-administered questionnaire was developed and distributed to medical students at the University of Santiago de Compostela. Comprising 44 items, the questionnaire assessed eight key dimensions: "infection diagnosis", "criteria for not prescribing antibiotics", "initial antibiotic therapy", "re-evaluation of therapy", "quality of care", "communication skills", "antibiotic resistance", and "teaching methodology". Validation was carried out in two stages: Phase 1 involved content and face validity, while Phase 2 focused on reliability analysis. Results: A total of 295 students completed the questionnaire, with a mean age of 23.15 ± 1.78 years. The sample included 86 male (29.2%) and 209 female (70.8%) respondents. Content and face validity were established by a nominal group of five experts and a focus group of medicine and pharmacy students to ensure consensus on item understanding in the Spanish language. The questionnaire demonstrated high internal consistency with a Cronbach's alpha of 0.92 and satisfactory item discrimination. Construct validity was confirmed through principal component analysis, which supported the presence of the eight predefined dimensions. Conclusions: The validated questionnaire exhibited strong reliability and validity, making it a valuable tool for assessing medical students' training in antibiotic-related topics. Its application will enable the identification of areas for improvement in university curricula, ultimately contributing to the promotion of appropriate antibiotic use and the reduction of antimicrobial resistance.

Directed evolution of antimicrobial peptides using multi-objective zeroth-order optimization

Antimicrobial peptides (AMPs) emerge as a type of promising therapeutic compounds that exhibit broad spectrum antimicrobial activity with high specificity and good tolerability. Natural AMPs usually need further rational design for improving antimicrobial activity and decreasing toxicity to human cells. Although several algorithms have been developed to optimize AMPs with desired properties, they explored the variations of AMPs in a discrete amino acid sequence space, usually suffering from low efficiency, lack diversity, and local optimum. In this work, we propose a novel directed evolution method, named PepZOO, for optimizing multi-properties of AMPs in a continuous representation space guided by multi-objective zeroth-order optimization. PepZOO projects AMPs from a discrete amino acid sequence space into continuous latent representation space by a variational autoencoder. Subsequently, the latent embeddings of prototype AMPs are taken as start points and iteratively updated according to the guidance of multi-objective zeroth-order optimization. Experimental results demonstrate PepZOO outperforms state-of-the-art methods on improving the multi-properties in terms of antimicrobial function, activity, toxicity, and binding affinity to the targets. Molecular docking and molecular dynamics simulations are further employed to validate the effectiveness of our method. Moreover, PepZOO can reveal important motifs which are required to maintain a particular property during the evolution by aligning the evolutionary sequences. PepZOO provides a novel research paradigm that optimizes AMPs by exploring property change instead of exploring sequence mutations, accelerating the discovery of potential therapeutic peptides.

Surface enhanced Raman spectroscopy and machine learning for identification of beta-lactam antibiotics resistance gene fragment in bacterial plasmid

BACKGROUND

Antibiotic resistance stands as a critical medical concern, notably evident in commonly prescribed beta-lactam antibiotics. The imperative need for expeditious and precise early detection methods underscores their role in facilitating timely intervention, curbing the propagation of antibiotic resistance, and enhancing patient outcomes.

RESULTS

This study introduces the utilization of surface-enhanced Raman spectroscopy (SERS) in tandem with machine learning (ML) for the sensitive detection of characteristic gene fragments responsible for antibiotic resistance appearance and spreading. To make the detection procedure close to the real case, we used bacterial plasmids as starting biological objects, containing or not the characteristic gene fragment (up to 1:10 ratio), encoding beta-lactam antibiotics resistance. The plasmids were subjected to enzymatic digestion and without preliminary purification or isolation the created fragments were captured by functional SERS substrates. Based on subsequent SERS measurements, a database was created for the training and validation of ML. Method validation was performed using separately measured spectra, which did not overlap with the database used for ML training. To check the efficiency of recognising the target fragment, control experiments involved bacterial plasmids containing different resistance genes, the use of inappropriate enzymes, or the absence of plasmid.

SIGNIFICANCE

SERS-ML allowed express detection of bacterial plasmids containing a characteristic gene fragment up to the 10-7 concentration of the initial plasmid, despite the complex composition of the biological sample, including the presence of interfering plasmids. Our approach offers a promising alternative to existing methods for monitoring antibiotic-resistant bacteria, characterized by its simplicity, low detection limit, and the potential for rapid and straightforward analysis.

Efficacy and Safety of Keratosept Eye Drops in Patients with Punctate Keratitis: Clinical and Microbiological Evaluation on 50 Eyes

We evaluated the efficacy and safety of eye drops with antiseptic and re-epithelizing properties (Keratosept®, Bruschettini, Genova, Italy) on 50 eyes affected by punctate keratitis of suspected microbial origin. A biomicroscopic examination, fluorescein dye staining test (Fluotest), tear break-up time test (TBUT), and the ocular surface disease Index (OSDI) questionnaire were used to assess treatment efficacy. Treatment success was defined as a negative Fluotest and an OSDI score <12 on the 15th day of treatment. According to this definition, Keratosept®, either alone or in combination with antibiotics, was effective in over 80% of microbial and nonmicrobial forms. Conjunctival swabs were taken from all patients for culture examination with an antibiogram and sensitivity test for Keratosept®; 32/43 (74.4%) forms with positive culture for the bacteria were sensitive to Keratosept®. A total of 35/38 (92%) eyes treated with this product alone achieved full treatment success without any apparent adverse effects. These results suggest the use of Keratosept® eye drops in punctate keratitis as an alternative or in combination with established antibiotic therapies. Further studies are needed to evaluate its efficacy in different infectious forms and identify other indications for using this product.

Safety and Efficacy of Dalbavancin in Real Life: Retrospective Analysis of a Large Monocentric Case Series of Patients Treated for Skin/Soft Tissue and Other Difficult-to-Treat Infections

Background: Dalbavancin is a long-acting lipoglycopeptide, approved for treatment of skin and skin structure infections. Its PK/PD profile and safety allow for short hospital stays even in the case of difficult-to-treat infections requiring long courses of therapy, e.g., osteomyelitis, cardiovascular, and prosthetic infections. Objectives: We aimed to evaluate the safety and efficacy of dalbavancin in real life settings for both in-label and off-label indications. Methods: retrospective evaluation of all consecutive patients treated with dalbavancin at our site between May 2017 and September 2021. Results: A total of 100 patients treated with dalbavancin and followed up for 6 months after treatment (58% male; median age 63.5 years, median Charlson Comorbidity Index CCI = 2.7, 28% inpatients) were included with the following indications: acute bacterial skin and skin structure infections (22%), bone and prosthetic infections (57%), and cardiovascular infections (19%). Infections were caused by MSSA (30%), MRSA (5%), MR-CoNS (20%), and Streptococcus spp. (8%). In 32 cases, no isolate was obtained. The average number of infusions was 5 (s.d. = 3). Neither ensuing alteration of renal function nor neutropenia or thrombocytopenia were observed during treatment and follow-up. Two self-limiting skin rashes occurred. The overall clinical success rate was 84%-91% for registered and 82% for unregistered indications. The prescription of higher loading doses was the only predictor independently associated with better outcomes in multivariate models (OR: 5.2, 95%CI: 1.5-17.9, p < 0.01). Conclusions: Dalbavancin proved to be effective for skin and skin structure infections, as well as for difficult-to-treat infections in highly comorbid patients. Regarding tolerability, our results support the use of dalbavancin for long-lasting treatments of deep-seated infections.

A scientific research training programme for teaching biomedical students to identify the horizontal transfer of antibiotic resistance genes

Worldwide prevalence of multi-antibiotic resistant bacteria is rapidly increasing, and the education of undergraduates and graduates about antibiotic resistance and its associated horizontal gene transfer is critical in the general effort to confront the spread of antibiotic resistance. In this study, a deeper understanding of antibiotic resistance and horizontal gene transfer was achieved by biomedical undergraduate students through a scientific research programme. The enthusiasm of students to participate in the training programme was very high, and results revealed that each student could identify the antibiotic resistance integrative and conjugative element from the Stenotrophomonas maltophilia MER1 genome. Each student could also draw the phylogenetic relationship of the antibiotic resistance integrative and conjugative element. In addition, students proved the horizontal transfer of antibiotic resistance genes from S. maltophilia MER1 to Escherichia coli strain 25DN through conjugation and PCR assays. Each group of students was able to obtain the expected results, indicating that the outcome of the scientific research programme was highly reproducible. This programme improved the theoretical knowledge about antibiotic resistance and horizontal gene transfer and the research skills of biomedical sciences students. Through this programme, students learned that antibiotic resistance genes can be horizontally transferred among different bacteria, laying a solid foundation for students to value the importance of the appropriate use of antibiotics in their future work and life.

Compatibility and antimicrobial activity of silver nanoparticles synthesized using Lycopersicon esculentum peels

Nanoparticles have gained worldwide attention as a new alternative to chemical control agents due to their special physiochemical properties. The current study focused on the environmentally friendly synthesis of silver nanoparticles (AgNPs) using Lycopersicon esculentum peel. In addition to studying the intrinsic cytotoxic effectiveness of Le-AgNPs contribute to their antibacterial, and antifungal activities and the effect of nanoparticles on the integrity of their morphological behavior. The initiative biosynthesis of L. esculentum silver nanoparticles (Le-AgNPs) was indicated by the color change of L. esculentum (Le) extract mixed with silver nitrate (AgNO3) solution from faint pink to faint brown. UV-visible spectroscopy, Dynamic light scattering (DLS), Fourier-transform infrared spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray diffraction techniques were used to characterize biosynthesized Le-AgNPs. Results of UV-visible spectroscopy recorded surface plasmon resonance at 310 nm for SPR of 2.5. The DLS results showed particles of 186 nm with a polydispersity index of 0.573. The FTIR spectrum indicated the existence of carboxyl, hydroxyl, phenolic, and amide functional groups. The HR-TEM analysis revealed quasi-spherical crystal particles of Le-AgNPs. Le-AgNPs had a negative zeta potential of - 68.44 mV, indicating high stability. Bacillus subtilis ATCC 6633 and Escherichia coli ATCC 8739 were the most susceptible pathogens to Le-AgNPs inhibition, with inhibition zone diameters (IZDs) of 4.0 and 0.92 cm, respectively. However, Listeria monocytogenes NC 013768 and Shigella sonnei DSM 5570 were the most resistant pathogens, with IZDs of 0.92 and 0.90 cm, respectively. Le-AgNPs demonstrated good inhibitory potential against pathogenic fungi, with IZDs of 3.0 and 0.92 cm against Alternaria solani ATCC 62102 and Candida albicans DSM 1386, respectively. The cytotoxicity effect was observed at a half-maximal inhibitory concentration (IC50) of 200.53 μg/ml on human colon NCM460D normal cells.

Analysis of antibiotic resistant infections associated with hirudotherapy

OBJECTIVE

Given rising concern regarding antibiotic resistance, our objective was to evaluate antibiotic-resistant infections following leech therapy and to characterize the use of prophylactic antibiotics.

METHODS

All reports of adverse events involving hirudotherapy (product code "NRN") were retrieved from the U.S. Food and Drug Administration MAUDE database between 2012 and 2021. Antibiotic resistance was defined by bacterial culture or infection after antibiotic administration.

RESULTS

Nineteen cases of antibiotic resistance involving hirudotherapy were identified. Only three cases of antibiotic resistance were discovered on routine testing and the remaining 16 cases were associated with patient injury. Positive blood cultures or fever were present in 26.3 % (n = 5) of cases. Cultures of the infection grew Aeromonas hydrophilia (n = 13; 68.4 %), Vibrio vulnificus (n = 3; 15.8 %), Pseudomonas aeruginosa (n = 2; 10.5 %), and Proteus vulgaris (n = 1; 5.3 %). There were nine (47.4 %) multi-drug resistant infections. Infection was most commonly resistant to fluoroquinolones (n = 9; 47.4 %), trimethoprim-sulfamethoxazole (n = 9; 47.4 %) and ertapenem (n = 4; 21.1 %).

CONCLUSION

Antibiotic-resistant infections involving hirudotherapy are frequently resistant to multiple drugs, including fluoroquinolones and trimethoprim-sulfamethoxazole. Resistance to ertapenem, a drug of last resort, was also documented. The findings presented in this study support growing literature that the trend in multi-drug resistance is more severe than previously reported.

Consumer acceptance of bacteriophage technology for microbial control

As global concerns and awareness of the threat posed by antimicrobial resistance (AMR) grow, the One Health initiative provides a framework to advance public understanding of and willingness to address AMR. The use of bacteriophages as a non-antibiotic means to control bacterial infections aligns with this framework, but it is unknown whether the use of new antibiotic alternatives, and bacteriophages in particular, will find acceptance among consumers. Within the context of poultry production and consumption, we sampled 1497 Pakistani consumers studying their knowledge of and familiarity with antibiotics, bacteriophages and AMR, whether they perceived AMR as a threat, and their willingness to accept alternative microbial control technologies. Additionally, we tested the impact information about bacteriophages had on the different concepts as well as respondents' perception of different chicken quality attributes. Using both Probit and Multivariate Probit models we found that familiarity with antibiotics and bacteriophages is significantly associated with the acceptance of alternative microbial control technologies and perceptions of resulting products. Moreover, we find that providing information about the technology does not significantly alter respondent's perception of most quality attributes.

Exploring the Membrane-Active Interactions of Antimicrobial Long-Chain Fatty Acids Using a Supported Lipid Bilayer Model for Gram-Positive Bacterial Membranes

The dynamic nature of bacterial lipid membranes significantly impacts the efficacy of antimicrobial therapies. However, traditional assay methods often fall short in replicating the complexity of these membranes, necessitating innovative approaches. Herein, we successfully fabricated model bacterially supported lipid bilayers (SLBs) that closely mimic the characteristics of Gram-positive bacteria using the solvent-assisted lipid bilayer (SALB) technique. By employing a quartz crystal microbalance with dissipation and fluorescence microscopy, we investigated the interactions between these bacterial mimetic membranes and long-chain unsaturated fatty acids. Specifically, linolenic acid (LNA) and linoleic acid (LLA) demonstrated interaction behaviors correlated with the critical micelle concentration (CMC) on Gram-positive membranes, resulting in membrane remodeling and removal at concentrations above their respective CMC values. In contrast, oleic acid (OA), while showing similar membrane remodeling patterns to LNA and LLA, exhibited membrane insertion and CMC-independent activity on the Gram-positive membranes. Particularly, LNA and LLA demonstrated bactericidal effects and promoted membrane permeability and ATP leakage in the bacterial membranes. OA, characterized by a CMC-independent activity profile, exhibited potent bactericidal effects due to its robust penetration into the SLBs, also enhancing membrane permeability and ATP leakage. These findings shed light on the intricate molecular mechanisms governing the interactions between long-chain unsaturated fatty acids and bacterial membranes. Importantly, this study underscores the potential of using biologically relevant model bacterial membrane systems to develop innovative strategies for combating bacterial infections and designing effective therapeutic agents.

Challenges of infectious diseases in older adults: From immunosenescence and inflammaging through antibiotic resistance to management strategies

Infectious diseases in older adults present a significant challenge to the healthcare system, marked by increased morbidity, mortality, and rising costs of care. Age-related changes (ARCs) in the immune system, including immunosenescence and inflammaging, contribute to heightened susceptibility to severe infections and reduced vaccine responsiveness. Additionally, alterations in the normal microbial flora due to aging and factors such as antibiotic therapy predispose older individuals to infections and age-related diseases. Changes in body composition also affect the pharmacokinetics and pharmacodynamics of drugs, complicating the management of antibiotics and leading to potential overdoses, adverse drug reactions, or underdoses that foster antibiotic resistance. The inappropriate use of antibiotics has exacerbated the emergence of multidrug-resistant pathogens, posing a critical global concern. This narrative review provides an overview of immunosenescence and inflammaging and focuses on three major infectious diseases affecting older adults: bacterial pneumonia, urinary tract infections, and Clostridium difficile infections. Through this exploration, we aim to highlight the need for targeted approaches in managing infectious diseases in the aging population.

Synthesis and Antimycobacterial Evaluation of Novel Pyrazole-Isoxazolines and Pyrazole-Isoxazoles

This study reports the synthesis of a new series of pyrazole-isoxazolines, at very good yields, from the cyclocondensation reaction of pyrazole-enaminones with hydroxylamine hydrochloride. Dehydration of the pyrazole-isoxazolines furnished another new series of the respective pyrazole-isoxazoles, at excellent yields. Both series of the obtained compounds were screened for antimycobacterial activity, and compounds 4 f and 5 c showed significant inhibition of bacterial growth with a time- and concentration-dependent bactericidal effect. Cytotoxicity tests in VERO cell line did not indicate toxicity of compounds 4 f and 5 c regarding cellular prediction, NO production or dsDNA release. However, both compounds were associated with an increase in total ROS levels, providing induction of oxidative stress, but without compromising cellular targets. These results highlight compounds 4 f and 5 c as promising candidates for antimycobacterial treatment with a favorable safety profile.

Nosocomial carbapenem-drug resistant Acinetobacter baumannii, related factors and clinical outcomes in Northeast Iran

BACKGROUND AND OBJECTIVES

Nosocomial infections, including drug-resistant Acinetobacter baumannii infections, continue to impact the health of hospitalized patients. This study sought to determine the prevalence of these infections and assess the associated risk factors and clinical outcomes in Gorgan, Iran.

METHODS

A retrospective cross-sectional study was conducted on 143 infected patients with Acinetobacter baumannii in two educational hospitals in Gorgan city, Iran between 2016 and 2018. Patient information including age, gender, reason and duration of hospitalization, background of diseases, type of sample culture, symptoms, laboratory findings, prescribed antibiotics, and antibiogram were collected and analyzed. The Logistic regression and survival statistical methods were used by software of SPSS 26.

RESULTS

A total of 37 patients (25.87%) died during hospitalization. The less than one year and 45-65 years age groups demonstrated more deaths (29.7%; p-value < 0.001). Being single (not being married) was found to be a risk factor in increasing the chance of death among patients (OR = 2.154, 95% CI: 1.02-4.53; p = 0.048). Hospitalization in intensive care units (ICUs) was a risk factor for the death of patients (OR = 4.655, 95% CI: 7.6-83.2). The resistance to carbapenems was reported to be an important risk factor for the death of patients.

CONCLUSIONS

Acinetobacter baumannii infections, particularly those resistant to carbapenems, are a significant risk for patients in ICUs and can lead to higher mortality rates.

The role of exopolysaccharides Psl and Pel in resistance of Pseudomonas aeruginosa to the oxidative stressors sodium hypochlorite and hydrogen peroxide

Pseudomonas aeruginosa is well-known for its antimicrobial resistance and the ability to survive in harsh environmental conditions due to an abundance of resistance mechanisms, including the formation of biofilms and the production of exopolysaccharides. Exopolysaccharides are among the major components of the extracellular matrix in biofilms and aggregates of P. aeruginosa. Although their contribution to antibiotic resistance has been previously shown, their roles in resistance to oxidative stressors remain largely elusive. Here, we studied the function of the exopolysaccharides Psl and Pel in the resistance of P. aeruginosa to the commonly used disinfectants and strong oxidizing agents NaOCl and H2O2. We observed that the simultaneous inactivation of Psl and Pel in P. aeruginosa PAO1 mutant strain ∆pslA pelF resulted in a significant increase in susceptibility to both NaOCl and H2O2. Further analyses revealed that Pel is more important for oxidative stress resistance in P. aeruginosa and that the form of Pel (i.e., cell-associated or cell-free) did not affect NaOCl susceptibility. Additionally, we show that Psl/Pel-negative strains are protected against oxidative stress in co-culture biofilms with P. aeruginosa PAO1 WT. Taken together, our results demonstrate that the EPS matrix and, more specifically, Pel exhibit protective functions against oxidative stressors such as NaOCl and H2O2 in P. aeruginosa.

IMPORTANCE

Biofilms are microbial communities of cells embedded in a self-produced polymeric matrix composed of polysaccharides, proteins, lipids, and extracellular DNA. Biofilm bacteria have been shown to possess unique characteristics, including increased stress resistance and higher antimicrobial tolerance, leading to failures in bacterial eradication during chronic infections or in technical settings, including drinking and wastewater industries. Previous studies have shown that in addition to conferring structure and stability to biofilms, the polysaccharides Psl and Pel are also involved in antibiotic resistance. This work provides evidence that these biofilm matrix components also contribute to the resistance of Pseudomonas aeruginosa to oxidative stressors including the widely used disinfectant NaOCl. Understanding the mechanisms by which bacteria escape antimicrobial agents, including strong oxidants, is urgently needed in the fight against antimicrobial resistance and will help in developing new strategies to eliminate resistant strains in any environmental, industrial, and clinical setting.