Global mortality associated with 33 bacterial pathogens in 2019: a systematic analysis for the Global Burden of Disease Study 2019

Activated platelet membrane vesicles for broad-spectrum bacterial pulmonary infections management

The development of new antibiotics has lagged behind the rapid evolution of bacterial resistance, prompting the exploration of alternative antimicrobial strategies. Host-directed therapy (HDT) has emerged as a promising approach by harnessing innate immune system's natural defense mechanisms, which reduces reliance on antibiotics, and mitigates the development of resistance. Building on the important role of platelets in host immunity, activated platelet membrane vesicles (PLTv) are developed here as a host-directed therapy for broad-spectrum antibacterial infection management, leveraging several key mechanisms of action. PLTv neutralizes bacterial toxins, thereby reducing cytotoxicity. The presence of platelet receptors on PLTv enables them to act as decoys, binding bacteria through receptor interactions and facilitating their phagocytosis by neutrophils and macrophages. Additionally, PLTv bound to bacteria promote the formation of neutrophil extracellular traps (NETs), enhancing the immune system's ability to trap and kill bacteria. In mouse models of pulmonary infections caused by the Methicillin-resistant Staphylococcus aureus, P. aeruginosa, and A. baumannii, administration of PLTv significantly reduces bacterial counts in the lungs and protects against mortality. Taken together, the present work highlights PLTv as a promising host-directed therapy for combating broad-spectrum pulmonary drug-resistant bacterial infections, leveraging their ability to neutralize toxins, act as decoys, promote phagocytosis, and facilitate NETs formation.

The global resistance problem and the clinical antibacterial pipeline

A comprehensive analysis of the clinical antibacterial pipeline demonstrates that there is a limited range of strategies that are primarily focused on modified versions of widely used chemical classes. These modifications aim to circumvent class-specific resistance mechanisms and reduce resistance rates in certain multidrug-resistant pathogens. Owing to the great variation in resistance rates and mechanisms, the clinical success of current approaches varies substantially across different countries, regions, and economic and environmental conditions, which affects the global societal value of these antibiotics that remain vulnerable to cross-resistance. Although there has been some progress in developing urgently needed antibiotics with novel targets and chemical structures, some of which have advanced to phase I/II trials, further breakthroughs are required. Additionally, adjunctive agents designed to enhance the outcome of conventional antibiotic therapies, along with bacteriophages that offer targeted and personalized treatments, are also under investigation. However, the potential of adjunctive therapeutics, such as antivirulence agents, and bacteriophages has yet to be realized in terms of feasibility and global societal impact.

Management of methicillin-resistant Staphylococcus aureus bloodstream infections: a comprehensive narrative review of available evidence focusing on current controversies and the challenges ahead

INTRODUCTION

Bloodstream infections (BSIs) caused by Staphylococcus aureus are common worldwide, representing one of the most relevant issues in clinical infectious diseases practice. In particular, BSIs by methicillin-resistant S. aureus (MRSA-BSI) are still today a challenge since mortality burden remains elevated although decades of research.

AREAS COVERED

The following topics regarding MRSA-BSI were reviewed and discussed by resorting to best available evidence retrieved from PubMed/MEDLINE up to October 2024: i) epidemiology; ii) microbiology; iii) classification, with a focus on complicated and not complicated forms; iv) the structured approach to the patient; v) pharmacokinetics and pharmacodynamics of the main antimicrobial options; vi) controversies regarding the best therapeutic approach.

EXPERT OPINION

Despite ongoing efforts to better stratify and manage MRSA-BSI, there is no universally accepted classification system accurately distinguishing between uncomplicated/low risk and complicated/high risk forms. Biomarkers such as interleukin(IL)-10 hold promise in order to enable a more precise stratification, premise for an appropriate treatment plan. There is a theoretical rationale for implementing a combination therapy including a beta-lactam agent upfront, especially for patients considered at higher risk of unfavorable outcomes, but further data are necessary, and the same applies to newer adjuvants. Novel microbiological techniques may help in guiding antimicrobial duration.

Management of Staphylococcus aureus Bacteremia: A Review

Importance

Staphylococcus aureus, a gram-positive bacterium, is the leading cause of death from bacteremia worldwide, with a case fatality rate of 15% to 30% and an estimated 300 000 deaths per year.

Observations

Staphylococcus aureus bacteremia causes metastatic infection in more than one-third of cases, including endocarditis (≈12%), septic arthritis (7%), vertebral osteomyelitis (≈4%), spinal epidural abscess, psoas abscess, splenic abscess, septic pulmonary emboli, and seeding of implantable medical devices. Patients with S aureus bacteremia commonly present with fever or symptoms from metastatic infection, such as pain in the back, joints, abdomen or extremities, and/or change in mental status. Risk factors include intravascular devices such as implantable cardiac devices and dialysis vascular catheters, recent surgical procedures, injection drug use, diabetes, and previous S aureus infection. Staphylococcus aureus bacteremia is detected with blood cultures. Prolonged S aureus bacteremia (≥48 hours) is associated with a 90-day mortality risk of 39%. All patients with S aureus bacteremia should undergo transthoracic echocardiography; transesophageal echocardiography should be performed in patients at high risk for endocarditis, such as those with persistent bacteremia, persistent fever, metastatic infection foci, or implantable cardiac devices. Other imaging modalities, such as computed tomography or magnetic resonance imaging, should be performed based on symptoms and localizing signs of metastatic infection. Staphylococcus aureus is categorized as methicillin-susceptible (MSSA) or methicillin-resistant (MRSA) based on susceptibility to β-lactam antibiotics. Initial treatment for S aureus bacteremia typically includes antibiotics active against MRSA such as vancomycin or daptomycin. Once antibiotic susceptibility results are available, antibiotics should be adjusted. Cefazolin or antistaphylococcal penicillins should be used for MSSA and vancomycin, daptomycin, or ceftobiprole for MRSA. Phase 3 trials for S aureus bacteremia demonstrated noninferiority of daptomycin to standard of care (treatment success, 53/120 [44%] vs 48/115 [42%]) and noninferiority of ceftobiprole to daptomycin (treatment success, 132/189 [70%] vs 136/198 [69%]). Source control is a critical component of treating S aureus bacteremia and may include removal of infected intravascular or implanted devices, drainage of abscesses, and surgical debridement.

Conclusions and relevance

Staphylococcus aureus bacteremia has a case fatality rate of 15% to 30% and causes 300 000 deaths per year worldwide. Empirical antibiotic treatment should include vancomycin or daptomycin, which are active against MRSA. Once S aureus susceptibilities are known, MSSA should be treated with cefazolin or an antistaphylococcal penicillin. Additional clinical management consists of identifying sites of metastatic infection and pursuing source control for identified foci of infection.

Ultra-short lipopeptides containing d-amino acid exhibiting excellent stability and antibacterial activity against gram-positive bacteria

As novel antibacterial agents, antimicrobial peptides (AMPs) possess broad-spectrum antibacterial activity and low drug resistance, holding significant development potential. Nevertheless, the stability of AMPs significantly restricts their application. In light of this, we synthesized a series of ultra-short lipopeptides using d-amino acid substitution to enhance the stability of ultra-short lipopeptide C12-RRW-NH2 that was selected from our previous research while maintaining its antibacterial activity against gram-positive bacteria. Amongst, the ultra-short lipopeptide Lip7 (C12-rrw-NH2) with full d-amino acid demonstrated outstanding stability in protease, serum, and salt ion environments. It exerted excellent antibacterial activity against gram-positive bacteria, especially against methicillin-resistant Staphylococcus aureus (MRSA). Meanwhile, Lip7 presented a low propensity to develop bacterial resistance with potential for combination therapy with conventional antibiotics. Studies on its antibacterial mechanism revealed that Lip7 could rapidly depolarize the bacterial cytoplasmic membrane, disrupt the integrity of the bacterial membrane, lead to leakage of nucleic acid and protein, promote the generation of reactive oxygen species, and ultimately result in bacterial death. Additionally, Lip7 also exhibited therapeutic potential in both local and systemic MRSA-infected mice models with better safety in vivo. These findings highlighted that Lip7 is an ideal novel antibacterial alternative to offer guiding schemes for developing high-stability antimicrobial peptides to fight multidrug-resistant gram-bacteria.

Infectious disease-specific health literacy and its influencing factors: Research results based on a cross-sectional design study carried out in Shandong Province's rural areas

Rural residents face a higher risk of infectious diseases, and infectious disease-specific health literacy (IDSHL) is a crucial means of managing these risks. This study intended to survey the levels of IDSHL among rural residents in Shandong Province, China, and explore the influencing factors of IDSHL. In 2022, a cross-sectional design investigation was carried out in Shandong Province of China, involving 2283 participants recruited through a multistage sampling approach in rural regions. A cognitive questionnaire was used to assess participants' levels of IDSHL. Pearson χ2 test was performed to compare the differences in the distribution of categorical variables between the adequate and inadequate IDSHL groups. Multicollinearity diagnosis analysis was utilized to evaluate multicollinearity. Multiple logistic regression was used to detect the possible influencing factors of IDSHL. Among the participants, 31.80% had adequate IDSHL. Multiple logistic regression demonstrated that education (odds ratio (OR)junior high school = .71, 95% confidence interval (CI) of OR: 0.51-0.99, P = .04; ORuniversity or above = 2.62, 95% CI of OR: 1.67-4.11, P < .01), occupation (ORbusiness = 2.19, 95% CI of OR: 1.34-3.57, P < .01; ORothers = 1.46, 95% CI of OR: 1.02-2.10, P = .04), family income (OR1-3 10,000 RMB = 2.83, 95% CI of OR: 1.98-4.05, P < .01; OR3-6 10,000 RMB = 1.75, 95% CI of OR: 1.21-2.53, P < .01), "whether the participant used a smartphone in daily life" (OR = 2.02, 95% CI of OR: 1.32-3.09, P < .01) and "whether knowledge of infectious disease prevention and control could be acquired" (OR = 11.77, 95% CI of OR: 6.44-21.54, P < .01) were associated with adequate IDSHL. The rural residents' level of adequate IDSHL in China's Shandong Province, was unsatisfactory. Special health education is needed to be implemented to enhance rural residents' IDSHL and should target key populations with low levels of IDSHL.

Influence of cell bioenergetics on host-pathogen interaction in the lung

Pulmonary diseases, arising from infections caused by bacteria, fungi, and viruses, or stemming from underlying genetic factors are one of the leading causes of mortality in humans, accounting for millions of deaths every year. At the onset of pulmonary diseases, crucial roles are played by phagocytic immune cells, particularly tissue-resident macrophages, in regulating the immune response at the mucosal barrier. Recent strides have illuminated the pivotal role of host bioenergetics modulated by metabolites derived from both pathogens and hosts in influencing the pathophysiology of major organs. Their influence extends to processes such as the infiltration of immune cells, activation of macrophages, and the polarization phenomenon. Furthermore, host-derived metabolites, such as itaconate, contribute to the promotion of anti-inflammatory responses, thereby preventing immunopathology and facilitating the preservation of mucosal niches to thrive for the long-term. This review explores recent advancements in the field of immunometabolism, with a particular emphasis on the intricacies of disease progression in pulmonary infections caused by bacteria such as P. aeruginosa, M. tuberculosis and S. aureus and fungi like C. albicans.

Extracellular nucleic acid-triggered precision responsive antibacterial strategy

AIMS

The emergence of antibiotic-resistant bacteria in recent years has underscored the urgent need for novel, precision-targeted antibacterial strategies. To address this critical challenge, our study designed a responsive antibacterial system that achieves precise bacterial eradication by conjugating antibacterial agents to nucleic acid probes wherein drug release is specifically triggered by extracellular nucleic acids.

METHODS AND RESULTS

This innovative design utilizes toehold-mediated strand displacement to enable single-nucleotide precision targeting of bacterial sequences, thereby ensuring highly specific and quantitative drug release. And drug release is specifically triggered by extracellular nucleic acids. Comprehensive evaluations, including bacterial growth inhibition curves, inhibition zone measurements, and fluorescence staining assays, demonstrated the exceptional stability and selectivity. Furthermore, the practicality of this strategy was validated in spiked environmental water samples, where significant antibacterial efficacy was observed, highlighting its real-world applicability.

CONCLUSIONS

The assembly, identification, and drug release process of this new antibacterial strategy have been thoroughly verified, showing excellent stability and selectivity, and also having excellent effects on the actual environment.

Research Progress on Antibacterial Applications of Bioactive Materials in Wound Infections: Design, Challenges, and Prospects

Bacterial wound infections pose a significant threat to global health, exacerbated by the increase in multidrug-resistant bacteria (MDRB) and the formation of elastic biofilms. This review explores the transformative potential of bioactive materials in addressing these challenges, focusing on their design, mechanisms of action, and therapeutic effects. In vivo, bioactive materials are designed to respond to unique bacterial microenvironment (BME), utilizing enzyme activity, controlled gas release, surface functionalization, and immune regulation to combat infections. In vitro, this review provides a comprehensive overview of the latest advances in the rational design of these materials, emphasizing the synergistic integration of structural modifications (such as size and morphology) with external physical stimuli (such as light, sound, electricity, magnetism, and force) to enhance antibacterial performance. Finally, the outstanding challenges and prospects in this rapidly evolving field are discussed.

Withanolide glycosides from Physalis volubilis

The study of the acetone and methanol extracts of the stems, leaves, and flowers of Physalis volubilis led to obtain four withanolide glycosides (4, 6, 10, and 14). Compounds 1-3, 13, 15, and a sterol glycoside were also isolated. The structures were established by analysis of spectroscopic and spectrometric data, and by chemical transformations. Nine of the obtained compounds (2, 3, 6, 7, 10, 11, and 13-15) were evaluated for their qualitative antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis. Compound 2 showed the highest inhibition of bacterial growth. Its minimum inhibitory concentrations against S. aureus ATCC® 25923™ and a clinical isolate of Methicillin-resistant S. aureus (MRSA) were 62.5 and 125 μg/mL, respectively.

How can surface-enhanced Raman spectroscopy improve diagnostics for bacterial infections?

Currently, bacterial infection is still a major global health issue. Although antibiotics have been widely used to control and treat bacterial infections, the overuse and misuse of antibiotics have led to widespread antimicrobial resistance among many bacterial pathogens. Therefore, reducing bacterial infections through rapid and accurate diagnostics is crucial for global public health. Traditional microbiological detection methods have limitations such as poor selectivity, high complexity, and excessive time consumption, highlighting the urgent need to develop efficient and sensitive bacterial diagnosis methods. Surface-enhanced Raman spectroscopy (SERS), as an emerging technique in clinical settings, holds a promising future for bacterial identification due to its rapid, nondestructive, and cost-effective nature. This invited special report discusses the application of SERS technology in bacterial diagnosis using pure culture, clinical samples, and single-cell Raman analysis. Current challenges and prospects of the technology are also addressed with in-depth discussion.

MultiSeq-AMR: a modular amplicon-sequencing workflow for rapid detection of bloodstream infection and antimicrobial resistance markers

Bloodstream infections (BSIs) represent a significant global health challenge, and traditional diagnostic methods are suboptimal for timely guiding targeted antibiotic therapy. We introduce MultiSeq-AMR, a rapid and modular nanopore amplicon-sequencing workflow to identify bacterial and fungal species and a comprehensive set of antimicrobial resistance (AMR) genes (n=91) from various types of infection sources. We initially benchmarked MultiSeq-AMR using DNA from 16 bacterial and 5 fungal reference strains and accurately identified all species. AMR gene identification exhibited 99.4% categorical agreement (CA: 153/154 prediction) with whole-genome sequencing. Further validation with 33 BACT/ALERT positive samples from suspected BSI cases revealed 100% accuracy for genus and 96.7% for species identification, with 97.4% CA (151/155) for AMR gene prediction. To accelerate microbiological diagnosis, a 6 h culture enrichment step was tested with MultiSeq-AMR using 15 clinically important bacterial species. Of 13 species selected for sequencing, 11 were correctly identified, with 96% CA (59/61 predictions) for AMR gene identification. With only 2 Mbp yield, sequencing identified 93.7% of species and 89.8% AMR genes initially detected with 20-50 Mbp yield/sample. MultiSeq-AMR holds promise for BSI diagnosis, as species/AMR genes could be identified under 5 h of BACT/ALERT positivity and potentially <11 h of sample collection (rapid-enrichment) for a large set of bacterial species. MultiSeq-AMR gene targets can be modified/increased indefinitely to suit user needs. Further research is required to clinically validate MultiSeq-AMR, especially the rapid enrichment method, to assess its utility in a medical setup and in improving patient outcomes in BSI.

Lipopeptides from Antarctic Bacillus siamensis N52R1 inhibit Pseudomonas aeruginosa biofilm

AIM

To search for active compounds produced by microorganisms isolated from the Antarctic environment, against biofilms of pathogenic bacteria Pseudomonas aeruginosa.

METHODS AND RESULTS

Seven different bacteria from Antarctic were cultivated, and their secretome (supernatants of the culture media) extracted using liquid/liquid partition, rendering 41 fractions of different polarities. Assays were performed to quantify P. aeruginosa pathogenic bacterial growth and inhibition of biofilm formation. From the tested Antarctic isolates, the polar hexane extract fraction of N52R1 strain, identified as Bacillus siamensis, showed activity against P. aeruginosa biofilm formation and was fractionated by reverse phase chromatography, corroborated by Confocal Laser Scanning Microscopy images. Applying LC-MS/MS (Liquid Chromatography - Tandem Mass Spectrometry) untargeted metabolomics, it is suggested that these results were obtained by the action of lipopeptide molecules, particularly plipastatin and surfactin, which has no previous report of activity upon the important pathogen P. aeruginosa. In vivo toxicity assays of the antibiofilm fraction of N52R1 upon the invertebrate Galleria mellonella was performed, showing no toxicity at up to 200 mg/kg.

CONCLUSION

We demonstrate the relevance and diversity of compounds from Antarctic microorganisms, in order to find bioactive agents against P. aeruginosa biofilm formation.

Prevalence and risk factors for Staphylococcus aureus colonisation among healthy individuals in low- and middle-income countries: A systematic review and meta-analysis

BACKGROUND

Staphylococcus aureus is capable of asymptomatic colonisation, which can progress to opportunistic and potentially life-threatening infection. The data on S. aureus colonisation in low- and middle-income countries (LMIC) are limited. This systematic review and meta-analysis estimates the prevalence of S. aureus colonisation in asymptomatic individuals in LMIC, with secondary objectives of assessing antimicrobial resistance, colonisation risk factors, and the molecular epidemiology of colonising strains.

METHODS

Articles published up to July 2023 were identified by searching four electronic databases. Studies that presented S. aureus colonisation prevalence in healthy individuals from a community setting in LMIC were included. Data extraction was performed independently by two reviewers with disagreement resolved through consensus. Studies were critically appraised using the Joanna Briggs Institute Prevalence tool. Random effects meta-analysis was conducted where appropriate. This study was registered in advance with PROSPERO (CRD42019147780).

FINDINGS

A total of 16 610 citations were identified of which 138 studies (59 732 participants) met the eligibility criteria. The majority of studies had a low risk of bias. The pooled prevalence of S. aureus colonisation at nose and/or throat sites was 26·4% (95% CI 23·8 - 29·1%). The prevalence of methicillin-resistance in colonising S. aureus strains was 15·0% (95% CI: 11·8 to 18·6%), with a higher prevalence observed in Africa compared to Asia and South America (22·5% vs. 13·1% vs. 5·4% respectively). Panton-Valentine leukocidin genes were present in 26·4% (95% CI: 17·1% to 32·8%) of 2531 isolates.

INTERPRETATION

While the prevalence of asymptomatic S. aureus colonisation in LMIC mirrors that found in high-income countries, there was a higher prevalence of antimicrobial resistance and other virulence factors. Variability in study methods and sparsity of data from many LMIC, underscore the need for a global approach to S. aureus surveillance. This will be critical for informing effective infection prevention strategies.

Inverse Oxide/Alloy-Structured Nanozymes with NIR-Triggered Enzymatic Cascade Regulation of ROS Homeostasis for Efficient Wound Healing

The precise spatiotemporal control of reactive oxygen species (ROS) generation and scavenging remains pivotal for infected wound healing. However, conventional nanozymes fail to adaptively regulate ROS dynamics across inflammatory and proliferative phases. A near-infrared (NIR)-activated inverse oxide/alloy-structured nanozyme (Co7Fe3/ZnO@C) is developed, featuring enzymatic cascade activities to tune ROS homeostasis through synergistic chemodynamic (CDT), photodynamic (PDT), and photothermal (PTT) therapies. The nanozyme orchestrates a self-regulated cascade: peroxidase (POD)-like activity initially generates bactericidal hydroxyl radicals in acidic wounds, while subsequent NIR triggers hot electron transfer from Co7Fe3 to ZnO, facilitating synchronized superoxide dismutase (SOD)-like, catalase (CAT)-like and hydroxyl radical antioxidant capacity (HORAC) activities to scavenge residual ROS. This cascaded network dynamically balances ROS production (POD) and scavenging (NIR-driven SOD/CAT/HORAC), eradicating bacteria while resolving inflammation. In vitro/vivo studies have shown that the proposed method for maintaining ROS homeostasis can markedly enhance the rate of wound healing by the regulation of the inflammatory environment within the injured tissue and the facilitation of rapid re-epithelialization. This work provides an intelligent nanozyme platform that simulates the function of natural enzymes and constructs a cascade reaction strategy to balance the antibacterial and anti-inflammatory demands in the wound microenvironment.

Assessing microbiota in vivo: debugging with medical imaging

The microbiota is integral to human health and has been mostly characterized through various ex vivo 'omic'-based approaches. To better understand the real-time function and impact of the microbiota, in vivo molecular imaging is required. With technologies such as positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT), insight into microbiological processes may be coupled to in vivo information. Noninvasive imaging enables longitudinal tracking of microbes and their components in real time; mapping of microbiota biodistribution, persistence and migration; and simultaneous monitoring of host physiological responses. The development of molecular imaging for clinical translation is an interdisciplinary science, with broad implications for deeper understanding of host-microbe interactions and the role(s) of the microbiome in health and disease.

Presence of multidrug-resistant bacteria on ready-to-use laryngoscope blades and handles: A cross-sectional study

BACKGROUND

The presence of microorganisms in laryngoscopes emphasizes the risk to patient safety during orotracheal intubations.

METHODS

A cross-sectional study was carried out in university hospital in the inpatient, emergency, intensive care, and surgical center sectors. Microorganisms were recovered from the blades using a filter membrane and from the handles using swab. They were then sown on blood agar plates and incubated at 35 °C (±2 °C) for a maximum of 5days. Microorganisms were identified by mass spectrometry, antimicrobial susceptibility tests were carried out for pathogenic bacteria. Associations were made using χ² and Fisher exact tests, and Poisson regression model.

RESULTS

A total of 158 blades and 45 handles were analyzed. Microbial growth was observed on 59.5% of the blades and 64.4% of the handles, with fungi and bacteria isolated, such as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter sp. Multidrug-resistant bacteria, producing extended-spectrum β-lactamases and carbapenemases, were found.

CONCLUSIONS

Multidrug-resistant bacteria were found on ready-to-use laryngoscopes. In the surgical center, there was lower probability of microbial growth, while the intensive care sector showed higher probability. This study reinforces the warning that this equipment is a potential source of transmission of microorganisms, especially multiresistant strains.

Evolution of Escherichia coli strains under competent or compromised adaptive immunity

Escherichia coli is a commensal of the intestine of most mammals, but also an important human pathogen. Within a healthy human its population structure is highly dynamic, where typically a dominant E. coli strain is accompanied by several low abundance satellite strains. However, the factors underlying E. coli strain dynamics and evolution within hosts are still poorly understood. Here, we colonised germ-free immune-competent (wild-type) or immune-compromised (Rag2KO) mice, with two phylogenetically distinct strains of E. coli, to determine if strain co-existence and within-strain evolution are shaped by the adaptive immune system. Irrespectively of the immune status of the mice one strain reaches a 100-fold larger abundance than the other. However, the abundance of the dominant strain is significantly higher in Rag2KO mice. Strains co-exist for thousands of generations and accumulate beneficial mutations in genes coding for different resource preferences. A higher rate of mutation accumulation in immune-compromised vs. immune-competent mice is observed and adaptative mutations specific to immune-competent mice are identified. Importantly, the presence of the adaptive immune system selects for mutations that increase stress resistance and the dynamics of such evolutionary events associates with the onset of an antibody response.

Okra juice used for rapid wound healing through its bioadhesive and antioxidant capabilities

Rapid wound healing is of great importance as it plays a crucial role in the body's response to injury or trauma. Biological adhesives are generally easy to apply, allowing for quick and efficient wound closure. In this study, we develop a natural biological adhesive derived from okra juice through a simple and environmentally friendly producing process. The strongest adhesion ability of this bioadhesive to wet tissue was 5.51 kPa, the ability to inhibit 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl radical, superoxide radical, hydroxyl radical, and hydrogen peroxide was 56.58 %, 49.94 %, 53.86 %, and 52.89 %, respectively, and the ability to promote cell proliferation was 181.46 %. The levels of pro-inflammatory tumor necrosis factor alpha (33.17 %) and Interleukin-6 (46.73 %) were significantly reduced. Both in vitro and in vivo evaluations indicate that it can effectively accelerate the healing process by sealing the wound, improving epithelial regeneration and angiogenesis, and alleviating inflammation. In addition, it has improved biocompatibility compared to commercial medical glue. Based on the favorable properties of the natural source, simple production process, and inherent nontoxicity, it shows potential as a medical bioadhesive for surgical procedures and emergency wound treatment.

Antibody responses in Klebsiella pneumoniae bloodstream infection: a prospective cohort study

BACKGROUND

Klebsiella pneumoniae is a leading cause of infection-related deaths globally, yet little is known about human antibody responses to invasive K pneumoniae. We sought to determine whether the O-specific polysaccharide antigen is immunogenic in humans with K pneumoniae bloodstream infection. We also sought to define the cross-reactivity of human antibody responses among structurally related K pneumoniae O-specific polysaccharide subtypes and to assess the effect of capsule production on O-specific polysaccharide-targeted antibody binding and function.

METHODS

In this prospective cohort study, we compared plasma antibody responses to O-specific polysaccharide in a cohort of consecutively enrolled patients with K pneumoniae bloodstream infection with controls, specifically a cohort of healthy individuals and a cohort of individuals with Enterococcus spp bloodstream infection. Patients were enrolled at the Massachusetts General Hospital, a tertiary hospital with affiliated clinics in the USA. We excluded patients whose isolates were not confirmed to be K pneumoniae by whole-genome sequencing. The primary outcome was the measurement of plasma IgG, IgM, and IgA antibody responses. We performed flow cytometry to measure the effects of K pneumoniae capsule production on O-specific polysaccharide antibody binding and O-specific polysaccharide antibody-mediated complement deposition, using patient isolates with variable levels of capsule production and isogenic capsule-deficient strains derived from these isolates.

FINDINGS

We enrolled 129 consecutive patients with suspected K pneumoniae bloodstream infection between July 24, 2021, and August 4, 2022, of whom 69 patients (44 [64%] male and 25 [36%] female) with confirmed K pneumoniae bloodstream infection were eligible for immunological evaluation. Common O-specific polysaccharide serotypes (O1, O2, O3, and O5) accounted for 57 (83%) of 69 infections. O-specific polysaccharide was immunogenic in patients with K pneumoniae bloodstream infection, and peak O-specific polysaccharide-IgG antibody responses in patients were ten-fold to 30-fold higher than antibody responses detected in healthy controls, depending on the serotype. There was cross-reactivity among similar O-specific polysaccharide subtypes, including the O1v1 and O1v2, O2v1 and O2v2, and O3 and O3b subtypes, as well as between the O1 and O2 types. Capsule produced by both hyperencapsulated and non-hyperencapsulated K pneumoniae inhibited O-specific polysaccharide-targeted antibody binding and function.

INTERPRETATION

O-specific polysaccharide was immunogenic in patients with K pneumoniae bloodstream infection, supporting its potential as a candidate vaccine antigen. The cross-reactivity observed between similar O-specific polysaccharide subtypes in patients with K pneumoniae bloodstream infection suggests that it might not be necessary to include all subtypes in an O-specific polysaccharide-based vaccine. However, these observations are tempered by the fact that capsule production, even in non-highly encapsulated strains, has the potential to interfere with O-specific polysaccharide antibody binding. This finding could limit the effectiveness of vaccines that exclusively target O-specific polysaccharide.

FUNDING

National Institute of Allergy and Infectious Diseases at the National Institutes of Health.

Intra-serotype variation of Streptococcus pneumoniae capsule and its quantification

Streptococcus pneumoniae (Spn) is a leading respiratory pathogen that depends on a thick layer of capsular polysaccharide (CPS) to evade immune clearance. Disease prevention by CPS-based vaccines is limited because of the species' high genome plasticity and ability to express over 100 different capsule types (serotypes). Generally, intra-serotype variations in capsulation are overlooked, despite the genetic variability of the bacterium. This oversight may result from a lack of standardized, reliable, and easily available methodology to quantify capsulation. Here, we have modified two methods to analyze the Spn capsule: immunoblot quantification of CPS in bacterial lysates and light microscopy to assess capsule thickness. Two assays were used because each measures distinct aspects of capsulation that could be differentially affected by the density of CPS. Quantification of either CPS amount or capsule thickness predicted the effectiveness of immune serum in opsonophagocytic killing assays for isogenic strains. Our standardized approaches both revealed significant differences in both CPS amount and capsule thickness among clinical isolates of the same serotype, challenging the assumption that intra-serotype capsulation is a conserved feature. As expected, these two methods show limited intra-strain correlation between amounts of CPS production and capsule thickness.

IMPORTANCE

Despite the availability of vaccines, Streptococcus pneumoniae remains a leading cause of respiratory and invasive diseases. These vaccines target a polysaccharide capsule the bacterium uses to evade the immune system. Variation of the capsule composition subdivides the organism into serotypes and influences its protective potency. Another critical factor affecting this protection is capsule size. It is commonly assumed that S. pneumoniae strains of the same serotype produce capsules of consistent size, despite the organism's heterogeneity. In this study, we challenge this assumption by analyzing clinical isolates of the same serotype. Existing methods were modified to achieve high reproducibility and increase accessibility. Our data reveal significant fluctuations in capsule production within a given serotype. Our findings suggest that S. pneumoniae research should consider capsule size, not just its presence and type. The results imply that standardized vaccine efficacy tests may yield variable results depending on the capsule production of target strains.

A Comprehensive Review of the Botany, Bioactive Compounds and Health Benefits of Leptospermum

There is increasing interest in research and application of natural bioactive compounds due to the growing demand for functional ingredients from the pharmaceutical, cosmetic and food industries. A major challenge is finding suitable natural plant resources for the development of functional ingredients. Leptospermum, a genus of the myrtle family (Myrtaceae), is primarily native to Australia. This genus has been traditionally used for the treatment of a range of ailments, such as colds, fever, constipation, diarrhoea, skin, inflammation, stomach disorder and both internal and external pain. Manuka honey, known for its medicinal properties, is produced from the nectar of Leptospermum flowers, and the leaves of some species are used for essential oil production. Various volatiles, such as pinene, citral and citronellal, have been identified in Leptospermum essential oils. In addition, various non-volatile compounds like leptosperin, cyanidin, quercetin, ellagic acid, delphinidin and myricetin have been isolated from Leptospermum extracts. Preliminary studies have linked Leptospermum essential oils and extracts with various health-promoting properties, such as antimicrobial activity, antidiabetes, anticancer and anti-Alzheimer's disease activities, revealing potential applications of Leptospermum as functional ingredients. To provide a comprehensive understanding of Leptospermum for future research and applications, this review presents an overview of its botanical features, outlines volatile and non-volatile active molecules identified in the genus, reviews potential health benefits and finally proposes trends for future studies on Leptospermum.

Helicid: A novel Anti-Staphylococcus aureus adjuvant

Staphylocoagulase (Coa) plays a critical role in the pathogenicity of Staphylococcus aureus (S. aureus). The present study was undertaken to investigate the underlying mechanism which helicid (HEL) suppressed the virulence factor Coa, as well as to assess the synergistic inhibitory effects of HEL in conjunction with antibiotics, thereby establishing the potential of HEL as an antibacterial adjuvant. We employed coagulation and biofilm assays to comprehensively assess the inhibitory impact of HEL on S. aureus pathogenicity. The thermal shift assay demonstrated that HEL exerted a direct impact on the protein stability of Coa, evidenced by a 6 °C change in melting temperature (ΔTm) at a concentration of 100 μM. HEL binding to Coa proteins was further validated by molecular dynamics simulations and fluorescence quenching. Molecular docking and point mutation assays identified S23 and D112 as crucial binding sites for HEL and Coa. Furthermore, HEL has been observed to potentiate the bactericidal properties of ceftaroline fosamil (CEF-F), concurrently diminishing the resistance exhibited by S. aureus towards CEF-F, as demonstrated by antibiotic synergy tests and resistance induction assays. The combination of HEL and CEF-F effectively reduced the number of bacteria and improved the survival of both Galleria mellonella larvae and mice. Additionally, a significant decrease was observed in the levels of TNF-α, IL-6, and IFN-γ in mice broncho-alveolar lavage fluid (BALF). Ultimately, our findings confirmed that the direct binding of HEL to Coa could diminish the pathogenicity of S. aureus. Moreover, the combination with CEF-F substantially reduced the lethality associated with S. aureus-infected pneumonia and extended the efficacy of the antibiotic.

The role of pharmacists in ensuring rational antibiotic therapy within the interdisciplinary team

The irrational use of antibiotics is one of the biggest threats to public health, as recently highlighted in the documents from the World Health Organization. It includes both the choice of an inappropriate drug, dose, form, or length of therapy for the patient, and a lack of attention to the global cost of treatment. One of the effects of excessive and irrational use of antibiotics worldwide is the increasing number of antibiotic-resistant microorganisms. The growing number of bacterial illnesses and deaths caused by this type of pathogens is of great significance, making the consequences of incorrect antibiotic use both medical and economic. In the rationalization of pharmacotherapy, the significant role of medical staff, including pharmacists, who have extensive knowledge in the field of antibiotic therapy, is emphasized. The main goal of the rational management of antimicrobial drugs should be to improve patient treatment outcomes and minimize the medical and economic consequences of antibiotic use. Antibiotic therapy rationalization programs are needed in all healthcare facilities, both in open care and in hospital settings. Educational interventions that target primary care physicians and physicians prescribing antibiotics in hospitals are necessary. Additionally, pharmacists, being the most accessible healthcare workers, can build awareness of rational antibiotic therapy among patients.

Serotype distribution of remaining invasive pneumococcal disease after extensive use of ten-valent and 13-valent pneumococcal conjugate vaccines (the PSERENADE project): a global surveillance analysis

BACKGROUND

Widespread use of pneumococcal conjugate vaccines (PCVs) has reduced vaccine-type invasive pneumococcal disease (IPD). We describe the serotype distribution of IPD after extensive use of ten-valent PCV (PCV10; Synflorix, GSK) and 13-valent PCV (PCV13; Prevenar 13, Pfizer) globally.

METHODS

IPD data were obtained from surveillance sites participating in the WHO-commissioned Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) project that exclusively used PCV10 or PCV13 (hereafter PCV10 and PCV13 sites, respectively) in their national immunisation programmes and had primary series uptake of at least 70%. Serotype distribution was estimated for IPD cases occurring 5 years or more after PCV10 or PCV13 introduction (ie, the mature period when the serotype distribution had stabilised) using multinomial Dirichlet regression, stratified by PCV product and age group (<5 years, 5-17 years, 18-49 years, and ≥50 years).

FINDINGS

The analysis included cases occurring primarily between 2015 and 2018 from 42 PCV13 sites (63 362 cases) and 12 PCV10 sites (6806 cases) in 41 countries. Sites were mostly high income (36 [67%] of 54) and used three-dose or four-dose booster schedules (44 [81%]). At PCV10 sites, PCV10 serotypes caused 10·0% (95% CI 6·3-12·9) of IPD cases in children younger than 5 years and 15·5% (13·4-19·3) of cases in adults aged 50 years or older, while PCV13 serotypes caused 52·1% (49·2-65·4) and 45·6% (40·0-50·0), respectively. At PCV13 sites, PCV13 serotypes caused 26·4% (21·3-30·0) of IPD cases in children younger than 5 years and 29·5% (27·5-33·0) of cases in adults aged 50 years or older. The leading serotype at PCV10 sites was 19A in children younger than 5 years (30·6% [95% CI 18·2-43·1]) and adults aged 50 years or older (14·8% [11·9-17·8]). Serotype 3 was a top-ranked serotype, causing about 9% of cases in children younger than 5 years and 14% in adults aged 50 years or older at both PCV10 and PCV13 sites. Across all age and PCV10 or PCV13 strata, the proportion of IPD targeted by higher-valency PCVs beyond PCV13 was 4·1-9·7% for PCV15, 13·5-36·0% for PCV20, 29·9-53·8% for PCV21, 15·6-42·0% for PCV24, and 31·5-50·1% for PCV25. All top-ten ranked non-PCV13 serotypes are included in at least one higher-valency PCV.

INTERPRETATION

The proportion of IPD due to serotypes included in PCVs in use was low in mature PCV10 and PCV13 settings. Serotype distribution differed between PCV10 and PCV13 sites and age groups. Higher-valency PCVs target most remaining IPD and are expected to extend impact.

FUNDING

Bill & Melinda Gates Foundation as part of the WHO Pneumococcal Vaccines Technical Coordination Project.

Effect of promethazine against Staphylococcus aureus and its preventive action in the formation of biofilms on silicone catheters

Urinary infections caused by Staphylococcus aureus are commonly associated with urinary catheterization and often result in severe complications. Given this problem, the objective of the study was to investigate the preventive action of promethazine (PMT) against the formation of methicillin-resistant Staphylococcus aureus (MRSA) biofilms when impregnated in urinary catheters. For this purpose, techniques such as broth microdilution, checkerboard, impregnation on urinary catheter fragments, flow cytometry assays and scanning electron microscopy were employed. PMT exhibited antimicrobial activity with Minimum Inhibitory Concentration (MIC) values ranging from 171 to 256 µg/mL, predominantly additive interaction in combination with oxacillin (OXA) and vancomycin (VAN), and a reduction in cell viability of biofilms formed and forming by methicillin-sensitive and -resistant S. aureus. Morphological alterations, damage to the membrane, and genetic material of cells treated with promethazine were also observed. The results demonstrated that PMT can be classified as a promising antimicrobial agent for use in the antibacterial coating of long-term urinary devices.

Gram-negative bloodstream infections in six German university hospitals, 2016-2020: clinical and microbiological features

PURPOSE

To analyze the longitudinal epidemiology and antimicrobial resistance (AMR) patterns of Gram-negative bloodstream infections (BSI) in Germany.

METHODS

Post-hoc analysis of prospectively documented BSI due to Escherichia coli, Klebsiella spp., Enterobacter spp., Pseudomonas aeruginosa and Acinetobacter baumannii from six university hospitals between 2016 and 2020. In a subanalysis 1228 episodes of BSI (E. coli N = 914, Klebsiella spp. N = 314) were analyzed for clinical endpoints and risk factors.

RESULTS

E. coli was the most prevalent cause of BSI, with 5412 cases, followed by Klebsiella spp. (2148 cases), P. aeruginosa (789 cases), Enterobacter spp. (696 cases), and A. baumannii (31 cases). BSI incidence rates were particularly high in haematology/oncology, with E. coli BSI reaching 13.9 per 1000 admissions. Most (58%) of the BSI episodes were community-acquired. A notable finding was the moderate increase of third-generation cephalosporin resistant Enterobacterales (3GCREB) for E. coli from 13.9% in 2016 to 14.4% in 2020 and a decrease for Klebsiella spp. from 16.5% in 2016 to 11.1% in 2020 corresponding to extended-spectrum betalactamase (ESBL) phenotype. In our analysis, the 3GCREB phenotype was not associated with a higher risk of death or discharge with sequelae for E. coli and Klebsiella spp.

CONCLUSION

Our study provides longitudinal data on Gram-negative BSI in Germany on a clinical basis for the first time. These data underscores the critical need for ongoing surveillance and more pathogen-related clinical data.

In Situ-Gelling Antimicrobial Poly(oligoethylene glycol methacrylate)-Based Hydrogels Integrating Bound Quaternary Ammonia Compounds and Antibiotic Functionalities for Effective Infected Wound Healing

In situ-gelling antibacterial hydrogels are reported in which two antibacterial entities (quaternary ammonium (QA) groups and the antibiotic ciprofloxacin (CIP)) are tethered to a single precursor based on the anti-fouling polymer poly(oligoethylene glycol methacrylate) (POEGMA). Synergism between the QA and CIP tethers is demonstrated to enable broad-spectrum killing and/or disinfection of both gram-positive and gram-negative bacteria both in vitro and in vivo while also supporting improved functional recovery of uninjured skin morphology. Coupled with the suitable mechanics, swelling capacity, and stability of the gels, the multi-mechanism antibacterial properties of the hydrogels offer promise for treating or preventing infections of burn wounds.

Streptococcus pneumoniae epidemiology, pathogenesis and control

Infections caused by Streptococcus pneumoniae (also known as pneumococci) pose a threat to human health. Pneumococcal infections are the most common cause of milder respiratory tract infections, such as otitis and sinusitis, and of more severe diseases, including pneumonia (with or without septicaemia) and meningitis. The introduction of pneumococcal conjugate vaccines in the childhood vaccination programme in many countries has led to a notable decrease of severe invasive pneumococcal disease in vaccinated children. However, infections caused by non-vaccine types have concurrently increased, causing invasive pneumococcal disease in unvaccinated populations (such as older adults), which has hampered the effect of these vaccines. Moreover, emerging antibiotic resistance is threatening effective therapy. Thus, new approaches are needed for the treatment and prevention of pneumococcal infections, and recent advances in the field may pave the way for new strategies. Recently, several important findings have been gained regarding pneumococcal epidemiology, genomics and the effect of the introduction of pneumococcal conjugate vaccines and of the COVID-19 pandemic. Moreover, elucidative pathogenesis studies have shown that the interactions between pneumococcal virulence factors and host receptors may be exploited for new therapies, and new vaccine candidates have been suggested. In this Review, we summarize some recent findings from clinical disease to basic pathogenesis studies that may be of importance for future control strategies.

Magnitude of Health Care Associated Infections and its Clinical Predictors in Ethiopia: A Systematic Review and Meta-Analysis

BACKGROUND

Health care-acquired infections (HCAIs) are the growing global public health problems facing today requiring an immediate collaborative action of stockholders to be prevented and controlled. Thus, this study was aimed to assess the magnitude and clinical related factors of HCAIs in Ethiopia.

METHODS

Articles were extensively searched in bibliographic databases and grey literatures using entry terms or phrases. Studies meeting eligibility criteria was extracted in Ms excel and exported in to STATA version 17 software for statistical analysis. A random-effect model was used to compute the pooled magnitude of HCAIs using meta-prop. The heterogeneity was quantified by using the I2 value. Publication bias was assessed using a funnel plot and Egger's test. Sensitivity analysis, meta-regression and subgroup analysis were computed.

RESULT

Of the 1707 studies identified, 33 studies were selected for meta-analysis of magnitude of HCAIs. The overall pooled prevalence of HCAIs in Ethiopia was 37% (95% CI: 27.0-47.0%). The predominant bacterial aetiologies were E. coli. There was no single study effect and publication bias. Diabetes mellitus, comorbidities, contaminated wound, history of UTI and history of admission in ICU were statistically significant clinical predictors of HCAIs.

CONCLUSION

the pooled prevalence of HCAIs have alarmingly increased which underscores the importance of implementation of personalized infection prevention and control approach which identifies patients at risk of HCAIs from the point of admission maximizes the potential for prevention of HCAIs.

Anthropogenic activity and climate change exacerbate the spread of pathogenic bacteria in the environment

Climate change is profoundly affecting human health. Human pathogenic bacteria (HPB) infections mediated by the environment are considered a substantial cause of global health losses. However, the biogeography of HPB and their response to climate change remain largely unknown. Here, we constructed and analyzed a global atlas of potential HPB using 1,066,584 samples worldwide. HPB are widely present in the global environment, and their distribution follows a latitudinal diversity gradient. Climate and anthropogenic factors are identified as major drivers of the global distribution of HPB. Our predictions indicated that by the end of this century, the richness, abundance, and invasion risk of HPB will increase globally, with this upward trend becoming more pronounced as development sustainability declines. Therefore, the threat of environmentally mediated HPB infections to human health may be more severe in a world where anthropogenic activities are intensifying and the global climate is warming.

Sludge amended soil induced multidrug and heavy metal resistance in endophytic Exiguobacterium sp. E21L: genomics evidences

The emergence of multidrug-resistant bacteria in agro-environments poses serious risks to public health and ecological balance. In this study, Exiguobacterium sp. E21L, an endophytic strain, was isolated from carrot leaves cultivated in soil amended with sewage treatment plant-derived sludge. The strain exhibited resistance to clinically relevant antibiotics, including beta-lactams, fluoroquinolones, aminoglycosides, and macrolides, with a high Multi-Antibiotic Resistance Index of 0.88. Whole-genome sequencing revealed a genome of 3.06 Mb, encoding 3894 protein-coding genes, including antimicrobial resistance genes (ARGs) such as blaNDM, ermF, tetW, and sul1, along with heavy metal resistance genes (HMRGs) like czcD, copB, and nikA. Genomic islands carrying ARGs and stress-related genes suggested potential horizontal gene transfer. The strain demonstrated robust biofilm formation, high cell hydrophobicity (> 80%), and significant auto-aggregation (90% at 48 h), correlating with genes associated with motility, quorum sensing, and stress adaptation. Notably, phenotypic assays confirmed survival under simulated gastrointestinal conditions, emphasizing its resilience in host-associated environments. Comparative genomics positioned Exiguobacterium sp. E21L near Exiguobacterium chiriqhucha RW-2, with a core genome of 2716 conserved genes. Functional annotations revealed genes involved in xenobiotic degradation, multidrug efflux pumps, and ABC-type transporters, indicating versatile resistance mechanisms and metabolic capabilities. The presence of ARGs, HMRGs, and MGEs (mobile genetic elements) highlights the potential role of Exiguobacterium sp. E21L as a reservoir for resistance determinants in agricultural ecosystems. These findings emphasized the need for stringent regulations on sludge-based fertilizers and advanced sludge treatment strategies to mitigate AMR risks in agro-environments.

Deep Learning Accelerates the Development of Antimicrobial Peptides Comprising 15 Amino Acids

The emergence of multidrug-resistant bacteria has led to an urgent need for novel antimicrobial agents. Antimicrobial peptides (AMPs) exhibit broad-spectrum and highly effective antibacterial activity and are less prone to resistance, making them potential candidates for the next generation of antimicrobial drugs. However, screening for AMPs from a vast library of peptides through wet lab experiments is a slow and laborious process. By leveraging large datasets of labeled peptides, researchers utilize deep learning algorithms to train models that capture complex patterns and features associated with antimicrobial activity, which advance the discovery and development of novel AMPs. Since the discovery of certain lengths of AMPs has been rarely reported, we applied deep learning to accelerate the discovery of AMPs consisting of 15 amino acids and developed a model named AMPPRED15 in this article. Wet lab experiments were also conducted to evaluate the performance of the model. Fortunately, we successfully identified two AMPs, one of which demonstrated antibacterial activities comparable to the marketed antibiotic cefoperazone sodium.

Towards a holistic approach to pulmonary infections. Insights from the Sixth Annual Meeting of Spanish Experts 2024

Pneumonia is the leading cause of death from infection in the developed world. In recent years, researchers and healthcare professionals have worked extensively to reduce this burden. Prevention is better than cure, and significant advances have been made in areas such as vaccination and the prevention of nosocomial pneumonia in intensive care units. Comprehensive surveillance programmes and new diagnostic methods have been developed to assess trends in this disease and to identify the infectious agents involved. Clinical presentation can be challenging in elderly patients or those with certain comorbidities, prompting new studies in these populations to address these issues. Correct and early management of severe community-acquired pneumonia represents a major opportunity to reduce its associated mortality. Although fungal pathogens are an uncommon cause of lung infection, they are associated with high morbidity and mortality, highlighting the need for new approaches. Finally, new drugs are available for the treatment of pneumonia, and a thorough understanding of them is key to ensuring their correct use, particularly to combat multi-resistance. To provide an update on these points, a multidisciplinary team of Spanish experts convened at the Sixth Annual Meeting of Pneumonia Day, under the scientific sponsorship of GEIPC-SEIMC. This paper reflects the information shared at this meeting, offering the latest insights on these topics and supporting a holistic approach to pneumonia management.

In Vitro and In Vivo Investigations into the Potential of Quinazoline and Quinoline Derivatives as NorA Efflux Pump Inhibitors Against Resistant Staphylococcus aureus Strains

Background:Staphylococcus aureus is a highly lethal Gram-positive bacterium that is responsible for over one million deaths annually. As a member of the ESKAPE pathogens, its methicillin-resistant strains (MRSA) are prevalent worldwide and exhibit significant antimicrobial resistance (AMR). Bacterial efflux pumps play a pivotal role in the development of AMR by facilitating the expulsion of a range of antimicrobial agents. Methods: The S. aureus strain SA-1199B, which overexpresses NorA and carries a GrlA mutation, was utilized to comprehensively profile the mechanism of the compounds PQQ16P and PQK4F. To assess the toxicity and genotoxicity of these compounds, RAW macrophages, HEK 293T, and HepG2 cell lines were utilized. Female BALB/c mice were utilized to assess the in vivo synergism of EPIs with CPX, Results: NorA efflux pump inhibitors (EPIs), PQQ16P and PQK4F, enhanced the efficacy of the antibacterial ciprofloxacin (CPX) against resistant S. aureus strains. The mechanism of EPIs involved the inhibition of NorA efflux pump, without compromising bacterial membrane permeability, ATP levels, or mammalian calcium channels. Moreover, the EPIs significantly augmented the bactericidal and post-antibiotic effects of CPX, elevating its mutation prevention concentration without manifesting substantial toxicity to human cells. Furthermore, the EPIs reduced S. aureus invasiveness in macrophages, indicating a role for NorA in bacterial virulence. Notably, the in vivo synergism of these EPIs with CPX was observed in a mouse infection model. Conclusions: This study provides substantial evidence for the potential of employing EPIs in a combination with CPX to counteract AMR, both in vitro and in vivo.

Ultrafast Charged MnO2 Nanosheets/Carbon Fiber with Mechanical and Postcharging Antibacterial Activity

Postcharging antibacterials have shown good application prospects in combating bacterial infections through electrical interaction. Herein, manganese oxide nanosheets in situ grown on carbon fibers (CM) are designed to perform the integration of mechanical intervention and postcharging therapy for efficient bacterial killing. This electrode disrupts bacterial membranes via sharp-edged microstructures. After charging at a low voltage in an ultrashort time, the charged CM affects the extracellular electron transfer (EET) of bacteria during the discharge process to kill the bacteria. Due to the dual-antibacterial mode, after charging at -1 V (vs saturated calomel electrode, SCE) for only 50.4 ± 3 s, the bacteria lethality rates of the CM against Escherichia coli and Staphylococcus aureus within 0.5 h both exceed 98%. Our developed ultrafast negatively charged CM exhibits high antibacterial activity and low cytotoxicity to fibroblast cells, providing a non-antibiotic approach to combat bacterial infection.

Insight into antistaphylococcal effect of chlorinated 1-hydroxynaphthalene-2-carboxanilides

Background and purpose

New compounds and innovative therapeutic approaches are trying to prevent antimicrobial resistance, which has become a global health challenge.

Experimental approach

This study includes a series of twelve mono-, di- and trichlorinated 1-hydroxynaphthalene-2-carboxanilides designed as multitarget agents. All compounds were evaluated for their antistaphylococcal activity. Furthermore, MTT assay and chemoproteomic analysis of selected compounds were performed. Cytotoxicity in human cells was also tested.

Key results

N-(3,5-Dichlorophenyl)-1-hydroxynaphthalene-2-carboxamide (10) demonstrated activity comparable to or higher than clinically used drugs, with minimum inhibitory concentrations (MICs) of 0.37 μM. The compound was equally effective against clinical isolates of methicillin-resistant S. aureus. On the other hand, compound 10 showed 96 % inhibition of S. aureus respiration only at a concentration of 16× MIC. Chemoproteomic analysis revealed that the effect of agent 10 on staphylococci resulted in the downregulation of four proteins. This compound expressed no in vitro cytotoxicity up to a concentration of 30 μM.

Conclusion

From the set of tested mono-, di- and trisubstituted derivatives, it is evident that the position of chlorine atoms is decisive for significant antistaphylococcal activity. Inhibition of energy metabolism does not appear to be one of the main mechanisms of action of compound 10; on the contrary, the antibacterial effect may likely be contributed by downregulation of proteins (especially ATP-dependent protease ATPase subunit HslU) involved in processes essential for bacterial survival and growth, such as protein, nucleotide/nucleic acid synthesis and efficient protein repair/degradation.

Risk of myocardial infarction and stroke following bloodstream infection: a population-based self-controlled case series

BACKGROUND

Cardiovascular disease (CVD) events triggered by inflammation are an underappreciated and poorly quantified cause of morbidity and mortality in patients with bloodstream infections (BSIs). We aimed to determine the risk of myocardial infarction (MI) and stroke after BSI.

METHODS

This self-controlled case series study was conducted within the Secure Anonymised Information Linkage Databank, containing anonymised population-scale electronic health record data for Wales, UK. We included adults with community-acquired BSI between 2010 and 2020. MI and stroke were determined from International Classification of Disease Version 10 coded admissions. Predefined risk periods after BSI were compared with the baseline period using pseudo-Poisson regression adjusted for age. Maximum C-reactive protein (CRP), a proxy for the magnitude of the inflammatory response, was determined within the first 7 days after BSI.

RESULTS

We identified 50 450 individuals with MI and 56 890 with stroke, of whom 1000 and 1290, respectively, also had at least one community-associated BSI. The risk of MI was most elevated in the first 1-7 days after BSI (adjusted incidence rate ratio (IRR) (95% CI): 9.67 (6.54 to 14.3)) and returned to baseline after 28 days. The risk was similarly elevated for stroke.The largest magnitude of risk was observed for those with a maximal CRP>300 mg/L (MI IRR: 21.54 (9.57 to 48.52); stroke IRR: 6.94 (3.14 to 15.32)).

CONCLUSION

BSI is associated with an increased risk of CVD events in the first 2 weeks after infection. Greater systemic inflammation was associated with a higher risk of CVD events and suggests targeting the inflammatory response caused by BSI warrants further study.

Characterization and host range prediction of Staphylococcus aureus phages through receptor-binding protein analysis

Bacteriophages are crucial in bacterial communities and can be used for therapy of multidrug-resistant pathogens such as Staphylococcusaureus. However, the host range of new phages remains difficult to predict. We identified the receptor-binding proteins (RBPs) of 335 S. aureus-infecting phages, yielding 8 distinct RBP clusters. Recombinant representative RBPs of all clusters, including several subclusters, were analyzed for binding to S. aureus strains differing in potential phage receptor structures. Notably, most of the phages encoded two separate RBPs, and all RBPs used S. aureus wall teichoic acid (WTA) polymers as receptors, albeit with varying preference for WTA glycosylation patterns and backbone structures. Based on these findings, a sequence-based tool for predicting the adsorption of new phages was developed. Moreover, one of the RBPs proved useful for identifying S. aureus-type WTA in other bacterial species. These findings facilitate the characterization of phage and bacterial isolates and the development of phage therapies.

Fast and Accurate Prediction of Antibiotic Susceptibility in Clinical Methicillin-Resistant S. aureus Isolates Using ATR-FTIR Spectroscopy: A Model Validation Study

Diagnosing antimicrobial resistance (AMR) remains critical for improving patient survival rates and treatment outcomes. Current antibiotic susceptibility tests (AST) suffer prolonged turnaround times, necessitating a minimum of 24 h for results. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy emerges as a promising phenotypic testing method in bacteriology due to its rapid chemical characterization capability. Here, we present an innovative approach utilizing ATR-FTIR spectroscopy for rapid AMR assessment, distinguishing between methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). Our approach focuses on detecting early markers of effective antibiotic action and using these to predict resistance profiles. To identify the earliest time for detection, five MSSA and five MRSA strains were subjected to oxacillin exposure for up to 2 h. We observed discernible molecular changes arising in MSSA as early as 1 h after exposure to oxacillin, which were absent in MRSA strains. Bands at 1624 and 1515 cm-1 were identified as markers of positive drug response in MSSA using principal component analysis (PCA) and were associated with peptidoglycan precursor accumulation upon transpeptidation inhibition. To develop predictive models for determining resistance profiles, we implemented ML-based modeling of the spectral data, reflective of the oxacillin-induced chemical composition changes in MSSA and MRSA. Partial least squares discriminant analysis (PLS-DA) and support vector machines classification (SVM-C) algorithms produced the best results, achieving 100% consistency with minimum inhibitory concentration (MIC) classification. Our models were independently validated by blind testing with 35 clinical strains and demonstrated 100% agreement with resistance profiling determined by MIC. Our study underscores the potential of ATR-FTIR spectroscopy for rapid and accurate AMR assessment, with the capacity to revolutionize diagnostics in combating antibiotic resistance.

IS26 carrying blaKPC-2 mediates carbapenem resistance heterogeneity in extensively drug-resistant Klebsiella pneumoniae isolated from clinical sites

BACKGROUND

Due to the widespread and irrational use of antibiotics, the emergence and prevalence of carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) have become a major challenge in controlling bacterial infections in hospitals. The blaKPC-2 gene located on mobile genetic elements has further complicated the control of resistant bacteria transmission.

RESULTS

In this study, K. pneumoniae strains were isolated from blood cultures of patients. Using the Kirby-Bauer disk diffusion method, we found carbapenem resistance heterogeneity. The resistant subpopulation KPTA-R1 and the sensitive subpopulation KPTA-S1 were purified. Whole-genome sequencing revealed that the blaKPC-2 gene in KPTA-R1 was located on an IncFII plasmid (pKPC-R), within a composite transposon (PCTs) formed by two direct repeats of IS26 elements. The structure was identified as IS26-RecA-ISKpn27-blaKPC-2-ISKpn6-IS26. However, in KPTA-S1, a similar plasmid, pAR-S, lacked this segment. Sequence comparison analysis indicates that the deletion of this blaKPC-2 encoding sequence in this IncFII plasmid is associated with transposition activity mediated by IS26. Multi-sequence comparison of the plasmids showed that the IS26 transposon facilitated the sequence polymorphism of these plasmids.

CONCLUSION

This study reveals the key role of IS26-mediated transposition activity, through homologous recombination, in the emergence of carbapenem resistance heterogeneity in clinical K. pneumoniae strains carrying blaKPC-2. IS26 is able to promote the evolution of resistance in the IncFII plasmid, and through copy-in cointegration or targeted conservative cointegration may result in the acquisition or loss of antibiotic resistance, which may affect clinical care and pose a public health risk.

Unraveling tetracycline and its degradation product: Induction mechanisms of antibiotic resistance in Escherichia coli

In aquatic environments, antibiotics degrade into byproducts, potentially enhancing bacterial resistance. However, the specific mechanisms by which these byproducts induce bacterial resistance remain elusive. This study conducted experimental evolution experiments to explore how E. coli adapts to tetracycline (TC) and its primary degradation products-anhydrotetracycline (ATC), epitetracycline (ETC), and 4-epianhydrotetracycline (EATC)-through evolution experiments. Prolonged exposure to TC and its byproducts significantly increased frequency of resistant mutants in E. coli ATCC25922, with a maximum 106-fold increase. Resistant mutants exhibited markedly elevated minimum inhibitory concentrations (MICs) for TC, ampicillin (AMP), and ciprofloxacin (CIP), indicating multidrug resistance. Transcriptomic analysis showed that the antibiotic resistance phenotype could be related to enhanced target protection, metabolic adaptations, and reduced membrane permeability. The induction pathways between TC and its byproducts were distinct. Specifically, TC20d (where TC20d represents the mutants collected after 20 days of continuous exposure to TC) was associated with more alterations in ribosome-associated genes, which was correlated with an enhanced defensive response as shown by the data. Moreover, variations in energy metabolism gene expression suggest a robust metabolic defense in ATC20d and ETC20d. When TC and its byproducts-ATC, ETC, and EATC-act together, they induce antibiotic resistant mutants at rates of 29.8 %, 18.9 %, 18.3 %, and 31.9 %, respectively. This study provides a descriptive overview of the possible adaptive mechanisms and pathways that may be involved in antibiotic resistance due to environmental exposure.

Insights into biofilm-mediated mechanisms driving last-resort antibiotic resistance in clinical ESKAPE pathogens

The rise of antibiotic-resistant bacteria poses a grave threat to global health, with the ESKAPE pathogens, which comprise Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. being among the most notorious. The World Health Organization has reserved a group of last-resort antibiotics for treating multidrug-resistant bacterial infections, including those caused by ESKAPE pathogens. This situation calls for a comprehensive understanding of the resistance mechanisms as it threatens public health and hinder progress toward the Sustainable Development Goal (SDG) 3: Good Health and Well-being. The present article reviews resistance mechanisms, focusing on emerging resistance mutations in multidrug-resistant ESKAPE pathogens, particularly against last-resort antibiotics, and describes the role of biofilm formation in multidrug-resistant ESKAPE pathogens. It discusses the latest therapeutic advances, including the use of antimicrobial peptides and CRISPR-Cas systems, and the modulation of quorum sensing and iron homeostasis, which offer promising strategies for countering resistance. The integration of CRISPR-based tools and biofilm-targeted approaches provides a potential framework for managing ESKAPE infections. By highlighting the spread of current resistance mutations and biofilm-targeted approaches, the review aims to contribute significantly to advancing our understanding and strategies in combatting this pressing global health challenge.

Diagnosis Accuracy of Raman Spectroscopy in the Identification of Pathogenic Bacteria

As an emerging technology, Raman spectroscopy (RS) has been used to identify pathogenic bacteria with excellent performance. The aim of this study was to verify the diagnosis accuracy of RS in identification of pathogenic bacteria. This meta-analysis systematically evaluated the accuracy of RS for identification of pathogenic bacteria. We searched the electronic databases of PubMed and Web of Science to obtain relevant articles; STATA 15.1 was used to analyze all sensitivities, specificies, and their 95% confidence interval (CI). The summary receiver operating characteristic curves (SROC) and area under the curve (AUC) were used to display more performance of RS. Nineteen articles were included according to the inclusion and exclusion criteria. The pooled sensitivity and specificity of RS for the identification of pathogenic bacteria were 0.94 (95% CI, 0.89-0.96) and 0.99 (95% CI, 0.97-0.99). The diagnostic odds ratio (DOR) was 1209 (95% CI, 367-3980), and AUC of SROC was 0.99 (95% CI, 0.98-1.00). For gram-positive bacteria, the sensitivity and specificity of different species ranged from 0.00 to 1.00 and 0.96 to 1.00, with a pooled sensitivity and specificity of 0.96 (95% CI, 0.90-0.98) and 0.99 (95% CI, 0.98-1.00). For gram-negative bacteria, the sensitivity and specificity of different species ranged from 0.30 to 1.00 and 0.92 to 1.00, with a pooled sensitivity and specificity of 0.92 (95% CI, 0.76-0.98) and 0.99 (95% CI, 0.98-1.00). For acid-fast bacteria, the sensitivity and specificity of different species ranged from 0.83 to 1.00 and 0.96 to 1.00, with a pooled sensitivity and specificity of 0.96 (95% CI, 0.84-0.99) and 1.00 (95% CI, 0.96-1.00). RS provides a new method for pathogenic bacteria identification and demonstrates high sensitivity and specificity for most included species.

Global prevalence of macrolide-resistant Staphylococcus spp.: a comprehensive systematic review and meta-analysis

Background

Staphylococcus is a genus of bacteria responsible for various infections ranging from mild skin to severe systemic diseases. Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) are significant challenges owing to their resistance to multiple antibiotics, including macrolides, such as erythromycin, clarithromycin, and azithromycin.

Objective

This study aimed to systematically review and synthesize data on the prevalence of macrolide resistance in Staphylococcus spp., identify trends and changes in resistance patterns over time, and assess how testing methods and guidelines affect reported resistance rates.

Methods

The study conducted a systematic search of the Scopus, PubMed, Web of Science, and EMBASE databases. Studies have reported the proportion of macrolide-resistant Staphylococcus spp. Two authors independently extracted and analyzed the data using a random-effects model. Heterogeneity was assessed, and subgroup analyses were performed based on country, continent, species, AST guidelines, methods, and period.

Results

In total, 223 studies from 76 countries were included. The pooled prevalence of resistance to erythromycin, clarithromycin, and azithromycin were 57.3, 52.6, and 57.9%, respectively. Significant heterogeneity was observed across studies (I2 > 95%, p < 0.001). Oceania (72%) had the highest erythromycin resistance, whereas Europe had the lowest (40.7%). Subgroup analyses revealed variations in resistance based on the species, with higher resistance in MRSA than in MSSA and CoNS than in other species. Over time, a slight decrease in erythromycin resistance has been observed (59.6% from 2015-2019 to 55% from 2020-2023).

Conclusion

This study emphasizes the high prevalence of macrolide resistance in Staphylococcus spp. and its notable regional variation. These findings highlight the necessity for standardized methodologies and global surveillance to manage macrolide resistance effectively. Controlling antibiotic resistance should prioritize enhancing public health measures and updating treatment guidelines.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=557756, CRD42024557756.

Splenic red pulp macrophages eliminate the liver-resistant Streptococcus pneumoniae from the blood circulation of mice

Invasive infections by encapsulated bacteria are the major cause of human morbidity and mortality. The liver resident macrophages, Kupffer cells, form the hepatic firewall to clear many encapsulated bacteria in the blood circulation but fail to control certain high-virulence capsule types. Here we report that the spleen is the backup immune organ to clear the liver-resistant serotypes of Streptococcus pneumoniae (pneumococcus), a leading human pathogen. Asplenic mice failed to control the growth of the liver-resistant pneumococci in the blood circulation. Immunologic and genetic analyses identified splenic red pulp (RP) macrophages as the major phagocytes for bacterial clearance. Furthermore, the plasma natural antibodies against the cell wall phosphocholine and the complement system were necessary for RP macrophage-mediated immunity. These findings have provided a conceptual framework for the innate defense against blood bacterial infections, a mechanistic explanation for the hyper-susceptibility of asplenic individuals to S. pneumoniae, and a proof of concept for developing vaccines and therapeutic antibodies against encapsulated pathogens.

Companions in antimicrobial resistance: examining transmission of common antimicrobial-resistant organisms between people and their dogs, cats, and horses

SUMMARYNumerous questions persist regarding the role of companion animals as potential reservoirs of antimicrobial-resistant organisms that can infect humans. While relative antimicrobial usage in companion animals is lower than that in humans, certain antimicrobial-resistant pathogens have comparable colonization rates in companion animals and their human counterparts, which inevitably raises questions regarding potential antimicrobial resistance (AMR) transmission. Furthermore, the close contact between pets and their owners, as well as pets, veterinary professionals, and the veterinary clinic environment, provides ample opportunity for zoonotic transmission of antimicrobial-resistant pathogens. Here we summarize what is known about the transmission of AMR and select antimicrobial-resistant organisms between companion animals (primarily dogs, cats, and horses) and humans. We also describe the global distribution of selected antimicrobial-resistant organisms in companion animals. The impact of interspecies AMR transmission within households and veterinary care settings is critically reviewed and discussed in the context of methicillin-resistant staphylococci, extended-spectrum β-lactamase and carbapenemase-producing bacteria. Key research areas are emphasized within established global action plans on AMR, offering valuable insights for shaping future research and surveillance initiatives.

Bacterial etiology and antimicrobial resistance in bloodstream infections at the University of Gondar Comprehensive Specialized Hospital: a cross-sectional study

Background

Bacterial bloodstream infections are a major global health concern, particularly in resource-limited settings including Ethiopia. There is a lack of updated and comprehensive data that integrates microbiological data and clinical findings. Therefore, this study aimed to characterize bacterial profiles, antimicrobial susceptibility, and associated factors in patients suspected of bloodstream infections at the University of Gondar Comprehensive Specialized Hospital.

Methods

A cross-sectional study analyzed electronic records from January 2019 to December 2021. Sociodemographic, clinical, and blood culture data were analyzed. Descriptive statistics and binary logistic regression were employed to identify factors associated with bloodstream infections. Descriptive statistics such as frequency and percentage were computed. Furthermore, a binary and multivariable logistic regression model was fitted to determine the relationship between BSI and associated factors. Variables with p-values of <0.05 from the multivariable logistic regression were used to show the presence of statistically significant associations.

Results

A total of 4,727 patients' records were included in the study. Among these, 14.8% (701/4,727) were bacterial bloodstream infections, with Gram-negative bacteria accounting for 63.5% (445/701) of cases. The most common bacteria were Klebsiella pneumoniae (29.0%), Staphylococcus aureus (23.5%), and Escherichia coli (8.4%). The study revealed a high resistance level to several antibiotics, with approximately 60.9% of the isolates demonstrating multidrug resistance. Klebsiella oxytoca, Klebsiella pneumoniae, and Escherichia coli exhibited high levels of multidrug resistance. The study identified emergency OPD [AOR = 3.2; (95% CI: 1.50-6.74)], oncology ward [AOR = 3.0; (95% CI: 1.21-7.17)], and surgical ward [AOR = 3.3; (95% CI: 1.27-8.43)] as factors associated with increased susceptibility to bloodstream infections.

Conclusion

The overall prevalence of bacterial isolates was high with concerning levels of multi-drug resistance. The study identified significant associations between bloodstream infections with age groups and presentation in specific clinical settings, such as the emergency OPD, oncology ward, and surgical ward. Strict regulation of antibiotic stewardship and the implementation of effective infection control programs should be enforced.

Antibiotic Treatment for 7 versus 14 Days in Patients with Bloodstream Infections

BACKGROUND

Bloodstream infections are associated with substantial morbidity and mortality. Early, appropriate antibiotic therapy is important, but the duration of treatment is uncertain.

METHODS

In a multicenter, noninferiority trial, we randomly assigned hospitalized patients (including patients in the intensive care unit [ICU]) who had bloodstream infection to receive antibiotic treatment for 7 days or 14 days. Antibiotic selection, dosing, and route were at the discretion of the treating team. We excluded patients with severe immunosuppression, foci requiring prolonged treatment, single cultures with possible contaminants, or cultures yielding Staphylococcus aureus. The primary outcome was death from any cause by 90 days after diagnosis of the bloodstream infection, with a noninferiority margin of 4 percentage points.

RESULTS

Across 74 hospitals in seven countries, 3608 patients underwent randomization and were included in the intention-to-treat analysis; 1814 patients were assigned to 7 days of antibiotic treatment, and 1794 to 14 days. At enrollment, 55.0% of patients were in the ICU and 45.0% were on hospital wards. Infections were acquired in the community (75.4%), hospital wards (13.4%) and ICUs (11.2%). Bacteremia most commonly originated from the urinary tract (42.2%), abdomen (18.8%), lung (13.0%), vascular catheters (6.3%), and skin or soft tissue (5.2%). By 90 days, 261 patients (14.5%) receiving antibiotics for 7 days had died and 286 patients (16.1%) receiving antibiotics for 14 days had died (difference, -1.6 percentage points [95.7% confidence interval {CI}, -4.0 to 0.8]), which showed the noninferiority of the shorter treatment duration. Patients were treated for longer than the assigned duration in 23.1% of the patients in the 7-day group and in 10.7% of the patients in the 14-day group. A per-protocol analysis also showed noninferiority (difference, -2.0 percentage points [95% CI, -4.5 to 0.6]). These findings were generally consistent across secondary clinical outcomes and across prespecified subgroups defined according to patient, pathogen, and syndrome characteristics.

CONCLUSIONS

Among hospitalized patients with bloodstream infection, antibiotic treatment for 7 days was noninferior to treatment for 14 days. (Funded by the Canadian Institutes of Health Research and others; BALANCE ClinicalTrials.gov number, NCT03005145.).