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Vitamin A and its biologically active derivative, retinoic acid (RA), are important for many immune processes. RA, in particular, is essential for the development of immune cells, including neutrophils, which serve as a front-line defense against infection. While vitamin A deficiency has been linked to higher susceptibility to infections, the precise role of vitamin A/RA in host-pathogen interactions remains poorly understood. Here, we provided evidence that RA boosts neutrophil killing of methicillin-resistant Staphylococcus aureus (MRSA). RA treatment stimulated primary human neutrophils to produce reactive oxygen species, neutrophil extracellular traps, and the antimicrobial peptide cathelicidin (LL-37). Because RA treatment was insufficient to reduce MRSA burden in an in vivo murine model of skin infection, we expanded our analysis to other infectious agents. RA did not affect the growth of a number of common bacterial pathogens, including MRSA, Escherichia coli K1 and Pseudomonas aeruginosa; however, RA directly inhibited the growth of group A Streptococcus (GAS). This antimicrobial effect, likely in combination with RA-mediated neutrophil boosting, resulted in substantial GAS killing in neutrophil killing assays conducted in the presence of RA. Furthermore, in a murine model of GAS skin infection, topical RA treatment showed therapeutic potential by reducing both skin lesion size and bacterial burden. These findings suggest that RA may hold promise as a therapeutic agent against GAS and perhaps other clinically significant human pathogens.

UNLABELLED: Infections caused by Staphylococcus aureus are a leading cause of mortality worldwide. S. aureus infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are particularly difficult to treat due to their resistance to next-generation β-lactams (NGBs) such as methicillin, nafcillin, and oxacillin. Resistance to NGBs, which is alternatively known as broad-spectrum β-lactam resistance, is classically mediated by PBP2a, a penicillin-binding protein encoded by mecA (or mecC) in MRSA. Thus, presence of mec genes among S. aureus spp. serves as the predictor of resistance to NGBs and facilitates determination of the proper therapeutic strategy for a staphylococcal infection. Although far less appreciated, mecA-deficient S. aureus strains can also exhibit NGB resistance. These strains, which are collectively termed as methicillin-resistant lacking mec (MRLM), are currently being identified in increasing numbers among natural resistant isolates of S. aureus. The mechanism/s through which MRLMs produce resistance to NGBs remains unknown. In this study, we demonstrate that mutations that alter PBP4 and GdpP functions, which are often present among MRLMs, can synergistically mediate resistance to NGBs. Furthermore, our results unravel that this novel mechanism potentially enables MRLMs to produce resistance toward NGBs at levels comparable to those of MRSAs. Our study provides a fresh new perspective about alternative mechanisms of NGB resistance, challenging our current overall understanding of high-level, broad-spectrum β-lactam resistance in S. aureus. It thus suggests reconsideration of the current approach toward diagnosis and treatment of β-lactam-resistant S. aureus infections. IMPORTANCE: In Staphylococcus aureus, high-level, broad-spectrum resistance to β-lactams such as methicillin, also referred to as methicillin resistance, is largely attributed to mecA. This study demonstrates that S. aureus strains that lack mecA but contain mutations that functionally alter PBP4 and GdpP can also mediate high-level, broad-spectrum resistance to β-lactams. Resistance brought about by the synergistic action of functionally altered PBP4 and GdpP was phenotypically comparable to that displayed by mecA, as seen by increased bacterial survival in the presence of β-lactams. An analysis of mutations detected in naturally isolated strains of S. aureus revealed that a significant proportion of them had similar pbp4 and GGDEF domain protein containing phosphodiesterase (gdpP) mutations, making this study clinically significant. This study not only identifies important players of non-classical mechanisms of β-lactam resistance but also indicates reconsideration of current clinical diagnosis and treatment protocols of S. aureus infections.

BackgroundOcular infections caused by antibiotic-resistant pathogens can result in partial or complete vision loss. The development of pan-resistant microbial strains poses a significant challenge for clinicians as there are limited antimicrobial options available. Synthetic peptoids, which are sequence-specific oligo-N-substituted glycines, offer potential as alternative antimicrobial agents to target multidrug-resistant bacteria.MethodsThe antimicrobial activity of synthesised peptoids against multidrug-resistant (MDR) ocular pathogens was evaluated using the microbroth dilution method. Hemolytic propensity was assessed using mammalian erythrocytes. Peptoids were also incubated with proteolytic enzymes, after which their minimum inhibitory activity against bacteria was re-evaluated.ResultsSeveral alkylated and brominated peptoids showed good inhibitory activity against multidrug-resistant Pseudomonas aeruginosa strains at concentrations of ≤15 μg mL-1 (≤12 µM). Similarly, most brominated compounds inhibited the growth of methicillin-resistant Staphylococcus aureus at 1.9 to 15 μg mL-1 (12 µM). The N-terminally alkylated peptoids caused less toxicity to erythrocytes. The peptoid denoted as TM5 had a high therapeutic index, being non-toxic to either erythrocytes or corneal epithelial cells, even at 15 to 22 times its MIC. Additionally, the peptoids were resistant to protease activity.ConclusionsPeptoids studied here demonstrated potent activity against various multidrug-resistant ocular pathogens. Their properties make them promising candidates for controlling vision-related morbidity associated with eye infections by antibiotic-resistant strains.

The skin provides an essential barrier for host defense through rapid action of multiple resident and recruited cell types, but the complex communication network governing these processes is incompletely understood. To define these cell-cell interactions more clearly, we performed an unbiased network analysis of mouse skin during invasive S. aureus infection and revealed a dominant role for CXCL12+ fibroblast subsets in neutrophil communication. These subsets predominantly reside in the reticular dermis, express adipocyte lineage markers, detect IL-17 and TNFα, and promote robust neutrophil recruitment through NFKBIZ-dependent release of CXCR2 ligands and CXCL12. Targeted deletion of Il17ra in mouse fibroblasts resulted in greatly reduced neutrophil recruitment and increased infection by S. aureus. Analogous human CXCL12+ fibroblast subsets abundantly express neutrophil chemotactic factors in psoriatic skin that are subsequently decreased upon therapeutic targeting of IL-17. These findings show that CXCL12+ dermal immune acting fibroblast subsets play a critical role in cutaneous neutrophil recruitment and host defense.

Host-directed therapy (HDT) is an emerging approach to overcome antimicrobial resistance in pathogenic microorganisms. Specifically, HDT targets host-encoded factors required for pathogen replication and survival without interfering with microbial growth or metabolism, thereby eliminating the risk of resistance development. By applying HDT and a drug repurposing approach, we demonstrate that (R)-DI-87, a clinical-stage anticancer drug and potent inhibitor of mammalian deoxycytidine kinase (dCK), mitigates Staphylococcus aureus abscess formation in organ tissues upon invasive bloodstream infection. Mechanistically, (R)-DI-87 shields phagocytes from staphylococcal death-effector deoxyribonucleosides that target dCK and the mammalian purine salvage pathway-apoptosis axis. In this manner, (R)-DI-87-mediated protection of immune cells amplifies macrophage infiltration into deep-seated abscesses, a phenomenon coupled with enhanced pathogen control, ameliorated immunopathology, and reduced disease severity. Thus, pharmaceutical blockade of dCK represents an advanced anti-infective intervention strategy against which staphylococci cannot develop resistance and may help to fight fatal infectious diseases in hospitalized patients.

Skin microbiome can be altered in patients with atopic dermatitis (AD). An understanding of the changes from healthy to atopic skin can help develop new targets for treatment by identifying microbial and molecular biomarkers. This study investigates the skin microbiome and metabolome of healthy adult subjects and lesion (ADL) and non-lesion (ADNL) of AD patients by 16S rRNA gene sequencing and mass spectrometry, respectively. Samples from AD patients showed alterations in the diversity and composition of the skin microbiome, with ADL skin having the greatest divergence. Staphylococcus species, especially S. aureus, were significantly increased in AD patients. Metabolomic profiles were also different between the groups. Dipeptide derivatives are more abundant in ADL, which may be related to skin inflammation. Co-occurrence network analysis of the microbiome and metabolomics data revealed higher co-occurrence of metabolites and bacteria in healthy ADNL compared to ADL. S. aureus co-occurred with dipeptide derivatives in ADL, while phytosphingosine-derived compounds showed co-occurrences with commensal bacteria, for example, Paracoccus sp., Pseudomonas sp., Prevotella bivia, Lactobacillus iners, Anaerococcus sp., Micrococcus sp., Corynebacterium ureicelerivorans, Corynebacterium massiliense, Streptococcus thermophilus, and Roseomonas mucosa, in healthy and ADNL groups. Therefore, these findings provide valuable insights into how AD affects the human skin metabolome and microbiome.IMPORTANCEThis study provides valuable insight into changes in the skin microbiome and associated metabolomic profiles in an adult population with mild to moderate atopic dermatitis. It also identifies new therapeutic targets that may be useful for developing personalized treatments for individuals with atopic dermatitis based on their unique skin microbiome and metabolic profiles.

The failure of the Staphylococcus aureus (SA) IsdB vaccine trial can be explained by the recall of non-protective immune imprints from prior SA exposure. Here, we investigate natural human SA humoral imprints to understand their broader impact on SA immunizations. We show that antibody responses against SA cell-wall-associated antigens (CWAs) are non-opsonic, while antibodies against SA toxins are neutralizing. Importantly, the protective characteristics of the antibody imprints accurately predict the failure of corresponding vaccines against CWAs and support vaccination against toxins. In passive immunization platforms, natural anti-SA human antibodies reduce the efficacy of the human monoclonal antibodies suvratoxumab and tefibazumab, consistent with the results of their respective clinical trials. Strikingly, in the absence of specific humoral memory responses, active immunizations are efficacious in both naive and SA-experienced mice. Overall, our study points to a practical and predictive approach to evaluate and develop SA vaccines based on pre-existing humoral imprint characteristics.

BACKGROUND: Community-acquired Staphylococcus aureus (CA-Sa) skin and soft tissue infections (SSTIs) are historically associated with densely populated urban areas experiencing high poverty rates, intravenous drug use, and homelessness. However, the epidemiology of CA-Sa SSTIs in the United States has been poorly understood since the plateau of the Community-acquired Methicillin-resistant Staphylococcus aureus epidemic in 2010. This study examines the spatial variation of CA-Sa SSTIs in a large, geographically heterogeneous population and identifies neighborhood characteristics associated with increased infection risk. METHODS: Using a unique neighborhood boundary, California Medical Service Study Areas, a hotspot analysis, and estimates of neighborhood infection risk ratios were conducted for all CA-Sa SSTIs presented in non-Federal California emergency departments between 2016 and 2019. A Bayesian Poisson regression model evaluated the association between neighborhood-level infection risk and population structure, neighborhood poverty rates, and being a healthcare shortage area. RESULTS: Emergency departments in more rural and mountainous parts of California experienced a higher burden of CA-Sa SSTIs between 2016 and 2019. Neighborhoods with high infection rates were more likely to have a high percentage of adults living below the federal poverty level and be a designated healthcare shortage area. Measures of population structure were not associated with infection risk in California neighborhoods. CONCLUSIONS: Our results highlight a potential change in the epidemiology of CA-Sa SSTIs in California emergency departments. Future studies should investigate the CA-Sa burden in other geographies to identify whether this shift in epidemiology holds across other states and populations. Further, a more thorough evaluation of potential mechanisms for the clustering of infections seen across California neighborhoods is needed.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important zoonotic pathogen associated with a wide range of infections in humans and animals. Thus, the emergence of MRSA clones poses an important threat to human and animal health. This study is aimed at elucidating the genomics insights of a strong biofilm-producing and multidrug-resistant (MDR) S. aureus MTR_BAU_H1 strain through whole-genome sequencing (WGS). The S. aureus MTR_BAU_H1 strain was isolated from food handlers hand swabs in Bangladesh and phenotypically assessed for antimicrobial susceptibility and biofilm production assays. The isolate was further undergone to high throughput WGS and analysed using different bioinformatics tools to elucidate the genetic diversity, molecular epidemiology, sequence type (ST), antimicrobial resistance, and virulence gene distribution. Phenotypic analyses revealed that the S. aureus MTR_BAU_H1 strain is a strong biofilm-former and carries both antimicrobial resistance (e.g., methicillin resistance; mecA, beta-lactam resistance; blaZ and tetracycline resistance; tetC) and virulence (e.g., sea, tsst, and PVL) genes. The genome of the S. aureus MTR_BAU_H1 belonged to ST1930 that possessed three plasmid replicons (e.g., rep16, rep7c, and rep19), seven prophages, and two clustered regularly interspaced short palindromic repeat (CRISPR) arrays of varying sizes. Phylogenetic analysis showed a close evolutionary relationship between the MTR_BAU_H1 genome and other MRSA clones of diverse hosts and demographics. The MTR_BAU_H1 genome harbours 42 antimicrobial resistance genes (ARGs), 128 virulence genes, and 273 SEED subsystems coding for the metabolism of amino acids, carbohydrates, proteins, cofactors, vitamins, minerals, and lipids. This is the first-ever WGS-based study of a strong biofilm-producing and MDR S. aureus strain isolated from human hand swabs in Bangladesh that unveils new information on the resistomes (ARGs and correlated mechanisms) and virulence potentials that might be linked to staphylococcal pathogenesis in both humans and animals.

INTRODUCTION: Staphylococcus aureus bacteremia (SAB) is a life-threatening infection particularly involving methicillin-resistant S. aureus (MRSA). In contrast to resolving MRSA bacteremia (RB), persistent MRSA bacteremia (PB) blood cultures remain positive despite appropriate antibiotic treatment. Host immune responses distinguishing PB vs. RB outcomes are poorly understood. Here, integrated transcriptomic, IL-10 cytokine levels, and genomic analyses sought to identify signatures differentiating PB vs. RB outcomes. METHODS: Whole-blood transcriptomes of propensity-matched PB (n=28) versus RB (n=30) patients treated with vancomycin were compared in one independent training patient cohort. Gene expression (GE) modules were analyzed and prioritized relative to host IL-10 cytokine levels and DNA methyltransferase-3A (DNMT3A) genotype. RESULTS: Differential expression of T and B lymphocyte gene expression early in MRSA bacteremia discriminated RB from PB outcomes. Significant increases in effector T and B cell signaling pathways correlated with RB, lower IL-10 cytokine levels and DNMT3A heterozygous A/C genotype. Importantly, a second PB and RB patient cohort analyzed in a masked manner demonstrated high predictive accuracy of differential signatures. DISCUSSION: Collectively, the present findings indicate that human PB involves dysregulated immunity characterized by impaired T and B cell responses associated with excessive IL-10 expression in context of the DNMT3A A/A genotype. These findings reveal distinct immunologic programs in PB vs. RB outcomes, enable future studies to define mechanisms by which host and/or pathogen drive differential signatures and may accelerate prediction of PB outcomes. Such prognostic assessment of host risk could significantly enhance early anti-infective interventions to avert PB and improve patient outcomes.

Brodies abscess is a manifestation of subacute to chronic osteomyelitis, characterized as intraosseous abscess formation, usually on the metaphysis of the long tubular bones in the lower extremities of male pediatric patients. Clinically, Brodies abscess presents with atraumatic bone pain of an insidious onset, with absence of systemic findings. Delay in diagnosis is common, as diagnostic imaging, followed by biopsy for culture and histologic examination are generally required to secure a diagnosis of Brodies abscess. Treatment of Brodies abscess is non-standardized, and usually consists of surgical debridement and antibacterial therapy. Despite the variability in therapeutic approaches, outcomes of Brodies abscess treated with surgery and antibiotics are favourable. Herein we report a case of a delayed diagnosis of Brodies abscess in the upper extremity of an adult female. While she improved with treatment of Brodies abscess, the case serves to remind clinicians to consider this entity in adult individuals who present with atraumatic bone pain.

Calcium phosphate cement (CPC), composed of silica-modified hydroxyapatite (HA-SiO 2), cerium oxide (CeO 2), and silica (SiO 2), was developed as an osteoporosis bone filler. The effect of CeO 2 and SiO 2 content on the CPC's properties, such as crystal parameters, surface properties, antibacterial activity, and toxicity properties, were studied. HA-SiO 2 was prepared using the sol-gel method, while CeO 2 was prepared using the precipitation method. HA in HA-SiO 2 has crystal properties similar to pure HA. Synthesized CeO 2 contains Ce3+ and Ce4+ ions with Ce3+/Ce4+ = 0.34. Computational calculation predicted that the CeO 2 (111) surface and glycine molecule interaction was categorized as chemisorption. Moreover, CeO 2 has antibacterial activity toward Escherichia coli and Staphylococcus aureus. Combining HA-SiO 2 and CeO 2 did not change the adsorption-desorption isotherm curve type, but slightly decreased the surface area, total pore volume, and average pore. Increasing the percentage of CeO 2 and adding 10 % SiO 2 (w/w) affected the particle's size and CeO 2 distribution. However, CPC lost antibacterial activity toward Staphylococcus aureus but adding 10 % SiO 2 (w/w) increases the bacterial activity toward Escherichia coli close to that of pure CeO 2. The MTT assay using pre-osteoblast MC3T3E1 cells showed that the CPC has IC 50 = 4227 μg/ml or is nontoxic. [Display omitted] [ABSTRACT FROM AUTHOR]

Staphylococcus aureus and Pseudomonas aeruginosa are the most common bacteria co-isolated from chronic infected wounds. Their interactions remain unclear but this coexistence is beneficial for both bacteria and may lead to resistance to antimicrobial treatments. Besides, developing an in vitro model where this coexistence is recreated remains challenging, making difficult their study. The aim of this work was to develop a reliable polymicrobial in vitro model of both species to further understand their interrelationships and the effects of different antimicrobials in coculture. In this work, bioluminescent and fluorescent bacteria were used to evaluate the activity of two antiseptics (chlorhexidine and thymol) against these bacteria planktonically grown, or when forming single and mixed biofilms. At the doses tested (0.4-1,000 mg/L), thymol showed selective antimicrobial action against S. aureus in planktonic and biofilm states, in contrast with chlorhexidine which exerted antimicrobial effects against both bacteria. Furthermore, the initial conditions for both bacteria in the co-culture determined the antimicrobial outcome, showing that P. aeruginosa impaired the proliferation and metabolism of S. aureus. Moreover, S. aureus showed an increased tolerance against antiseptic treatments when co-cultured, attributed to the formation of a thicker mixed biofilm compared to those obtained when monocultured, and also, by the reduction of S. aureus metabolic activity induced by diffusible molecules produced by P. aeruginosa. This work underlines the relevance of polymicrobial populations and their crosstalk and microenvironment in the search of disruptive and effective treatments for polymicrobial biofilms. [ABSTRACT FROM AUTHOR]

Bacterial toxin‐antitoxin (TA) systems consist of a toxin that inhibits essential cellular processes, such as DNA replication, transcription, translation, or ATP synthesis, and an antitoxin neutralizing their cognate toxin. These systems have roles in programmed cell death, defense against phage, and the formation of persister cells. Here, we characterized the previously identified Staphylococcus aureus TA system, tsaAT, which consists of two putative membrane proteins: TsaT and TsaA. Expression of the TsaT toxin caused cell death and disrupted membrane integrity, whereas TsaA did not show any toxicity and neutralized the toxicity of TsaT. Furthermore, subcellular fractionation analysis demonstrated that both TsaA and TsaT localized to the cytoplasmic membrane of S. aureus expressing either or both 3xFLAG‐tagged TsaA and 3xFLAG‐tagged TsaT. Taken together, these results demonstrate that the TsaAT TA system consists of two membrane proteins, TsaA and TsaT, where TsaT disrupts membrane integrity, ultimately leading to cell death. Although sequence analyses showed that the tsaA and tsaT genes were conserved among Staphylococcus species, amino acid substitutions between TsaT orthologs highlighted the critical role of the 6th residue for its toxicity. Further amino acid substitutions indicated that the glutamic acid residue at position 63 in the TsaA antitoxin and the cluster of five lysine residues in the TsaT toxin are involved in TsaA's neutralization reaction. This study is the first to describe a bacterial TA system wherein both toxin and antitoxin are membrane proteins. These findings contribute to our understanding of S. aureus TA systems and, more generally, give new insight into highly diverse bacterial TA systems. [ABSTRACT FROM AUTHOR]

ABSTRACT The frequency of emerging disease is growing with ongoing human activity facilitating new host–pathogen interactions. Novel infection outcomes can also be shaped by the host microbiota. Caenorhabditis elegans nematodes experimentally colonised by a wild microbiota community and infected by the widespread animal pathogen, Staphylococcus aureus, have been shown to suffer higher mortality than those infected by the pathogen alone. Understanding the host responses to such microbiota–pathogen ecological interactions is key to pinpointing the mechanism underlying severe infection outcomes. We conducted transcriptomic analyses of C. elegans colonised by its native microbiota, S. aureus and both in combination. Correlations between altered collagen gene expression and heightened mortality in co‐colonised hosts suggest the microbiota modified host resistance to infection. Furthermore, microbiota colonised hosts showed increased expression of immunity genes and variable expression of stress response genes during infection. Changes in host immunity and stress response could encompass both causes and effects of severe infection outcomes. ‘Re‐wilding’ this model nematode host with its native microbiota indicated that typically commensal microbes can mediate molecular changes in the host that are costly when challenged by a novel emerging pathogen. [ABSTRACT FROM AUTHOR]

Seborrheic dermatitis (SD) is a common, multifaceted skin condition, but its undefined etiology hampers the development of effective therapeutic strategies. In this review, we describe the intricate relationship between the skin microbiome and the pathogenesis of SD, focusing on the complex interplay between three major groups of organisms that can either induce inflammation (Malassezia spp., Staphylococcus aureus) or else promote healthy skin (Propionibacterium spp.). We describe how the disequilibrium of these microorganisms in the skin microbiome can develop skin inflammation in SD patients. Understanding these complex interactions of the skin microbiome has led to development of novel probiotics (e.g., Vitreoscilla spp. and Lactobacillus spp.) to restore normal skin physiology in SD. There are also differences in the skin microbiomes of healthy and SD infant and adult patients that impact pathogenesis and prompt different management strategies. A deeper understanding of the skin microbiome and its dynamic interactions will provide valuable insights into the pathogenesis of SD and prompt further development of targeted probiotic treatments to restore the balance of the skin microbiome in SD patients. [ABSTRACT FROM AUTHOR]

Introduction: Diabetes mellitus is a chronic metabolic disorder characterized by persistent hyperglycemia due to impaired insulin production or utilization, leading to severe health complications. Diabetic foot ulcers (DFUs) represent a major complication, often exacerbated by polymicrobial infections involving Staphylococcus aureus and Acinetobacter baumannii. These pathogens, notorious for their resistance to antibiotics, complicate treatment efforts, especially due to biofilm formation, which enhances bacterial survival and resistance. This study explores the synergistic effects of combining gentamicin, imipenem, and fucoidan, a sulfated polysaccharide with antimicrobial properties, against both planktonic and biofilm forms of S. aureus and A. baumannii. Methods: Isolates of S. aureus and A. baumannii were collected from DFUs and genetically confirmed. Methicillin resistance in S. aureus was identified through disk diffusion and PCR. Biofilm formation, including dual-species biofilms, was analyzed using the microtiter plate method. The antimicrobial efficacy of gentamicin, imipenem, and fucoidan was assessed by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), and minimum biofilm eradication concentration (MBEC). Synergistic interactions were evaluated using the fractional inhibitory concentration index (FICi) and fractional bactericidal concentration index (FBCi). The expression of biofilm-associated genes (icaA in S. aureus and bap in A. baumannii) was analyzed, and the cytotoxicity of fucoidan was assessed. Results: The study revealed that 77.4% of S. aureus and all A. baumannii isolates showed multidrug resistance. Among 837 tested conditions for dual-species biofilm formation, 72 resulted in strong biofilm formation and 67 in moderate biofilm formation. The geometric mean MIC values for gentamicin were 12.2 µg/mL for S. aureus, 22.62 µg/mL for A. baumannii, and 5.87 µg/mL for their co-culture; for imipenem, they were 19.84, 9.18, and 3.70 µg/mL, respectively, and for fucoidan, 48.50, 31.20, and 19.65 µg/mL, respectively. The MBC values for gentamicin were 119.42, 128, and 11.75 µg/mL; for imipenem, they were 48.50, 14.92, and 8 µg/mL; and for fucoidan, they were 88.37, 62.62, and 42.48 µg/mL. The MBIC values were 55.71, 119.42, and 18.66 µg/mL for gentamicin; 68.59, 48.50, and 25.39 µg/mL for imipenem; and 153.89, 101.49, and 53.53 µg/mL for fucoidan. The MBEC values were 315.17, 362.03, and 59.25 µg/mL for gentamicin; 207.93, 157.58, and 74.65 µg/mL for imipenem; and 353.55, 189.46, and 99.19 µg/mL for fucoidan. When cultured in planktonic form, the geometric mean FICi and FBCi values indicated additive effects, while co-culture showed FICi values of ≤ 0.5, suggesting a synergistic interaction. Treatment with gentamicin and fucoidan led to significant downregulation of the icaA and bap genes in both single-species and dual-species biofilms of S. aureus and A. baumannii. The reductions in gene expression were more pronounced in dual-species biofilms compared to single-species biofilms. Additionally, treatment with imipenem and fucoidan also resulted in significant downregulation of these genes in both biofilm types. Cytotoxicity assessments indicated that higher concentrations of fucoidan were toxic, yet no harmful effects were noted at the optimal synergistic concentrations used with antibiotics. Conclusion: In our investigation, we found that combining gentamicin, imipenem, and fucoidan had a synergistic effect on dual-species biofilms of S. aureus and A. baumannii, suggesting potential benefits for treating such infections effectively. This underscores the importance of understanding microbial interactions, antibiotic susceptibility, and biofilm formation in DFUs. [ABSTRACT FROM AUTHOR]

Disruption in the wound-healing process is caused by the presence of bacteria and leads to major problems and delays in wound healing. The limitations of commonly used medicines for treating wound infections include drug toxicity, insufficient microbial coverage, poor penetration, and increased resistance. This study aimed to determine the effect of ciprofloxacin loaded in solid lipid nanoparticles (Cip-SLN) on Pseudomonas aeruginosa and ampiciliin-vancomycin loaded in solid lipid nanoparticles (Amp-Van-SLN) on Staphylococcus aureus in wounds. Antibiotics were encapsulated in SLNs using the double emulsion method and were characterized. The in-vitro effect of antibiotic-loaded nanoparticles on P. aeruginosa and S. aureus was assessed using well diffusion and MIC methods. Finally, the topical antibacterial activity of these nanoparticles against bacterial wound infection was measured in a mouse model. MIC results showed that in the first 24 hours, the free drug had a greater effect on inhibiting bacteria, and in 72 hours, the inhibitory effect of nanoparticles increased. There was no toxicity effect of 400 µg/mL of nanoparticles on cells. According to the findings, the groups treated with Cip-SLN and Amp-Van-SLN were more effective than the control group (untreated) in different concentrations. In the wound healing process, the group treated with solid lipid nanoparticles (SLNs) exhibited a greater epithelial thickness, indicating enhanced healing, compared to the group treated with the free drug. The use of SLN can increase the accumulation of antibiotics at the site of infection with a slow release of the drug due to its fatty nature, which leads to a significant inhibitory effect on bacteria and also improves wound healing. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus, a notorious member of the ESKAPE pathogens, poses significant public health challenges due to its virulence and multidrug-resistant nature, particularly in methicillin-resistant S. aureus (MRSA) strains. With the increasing threat of antibiotic resistance, there is an urgent need to develop novel antibiotic agents. This study therefore aims to explore the antibacterial potential of 1,2-dibenzoylhydrazine (DBH) as a scaffold against S. aureus drug target enzymes, using integrated computational approaches. The study utilized molecular docking, lead optimization, and structure-based virtual screening techniques to evaluate the binding affinities of DBH and its derivatives against various S. aureus enzymes. Prime/MM-GBSA calculations were performed to validate the binding affinities obtained, and molecular dynamics (MD) simulations were conducted to assess the stability of the DBHs-enzyme complexes. Results indicated that, out of twenty enzymes from S. aureus examined against DBH, carotenoid dehydrosqualene synthase was predicted as a suitable target enzyme for DBH, showing a binding affinity of -8.027 kcal/mol. A lead optimization operation of the compound generated 27 DBH derivatives out of which four exhibited enhanced binding affinities compared to both DBH and a standard antibiotic, ofloxacin. The QSAR model predicted that, DBH and molecule_D_1 have higher PIC50 of 4.779 µM compared with the standard drug (ofloxacin = 4.678 µM). MD simulations confirmed the stability of the top-scoring derivatives within the enzyme's binding pocket, with RMSD and RMSF analyses supporting their potential as inhibitors of the enzyme. In conclusion, this study has predicted the effect of DBH derivatives on S. aureus based on their in silico inhibitory capacity against the carotenoid dehydrosqualene synthase from the organism. Future work will seek to experimentally validate these findings against the suggested enzyme. [ABSTRACT FROM AUTHOR]

Background: Methicillin-Resistant Staphylococcus aureus (MRSA) is one of the most resistant bacteria to antibiotics. S. aureus is an important, widespread pathogen that can cause a variety of infectious diseases in humans and animals. Phages have been recognized as natural, safe, highly specific and effective alternatives agents to antibiotics for preventing and treating bacterial infections caused by MRSA. Therefore, this study aims at the characterization of a novel isolated lytic phage, vB_SauP_ASUmrsa123. Methods: Isolates of Staphylococcus aureus MRSA were obtained on Mannitol Salt Agar and Baird Parker Agar plates and confirmed using VITEK 2. Sewage and clinical samples were used to isolate specific phages for S. aureus MRSA, and plaque assays were used for host range determination on Luria-Bertani (LB) media. The phage morphology of the isolated phage was determined by transmission electron microscopy. The phage's whole genome sequencing was identified. Results: A total of 25 isolates of Staphylococci were obtained from different clinical sources and showed typical colonies on Baird-Parker and Mannitol Salt Agar plates. The VITEK 2 automated system revealed that all 25 isolates were confirmed as S. aureus (MRSA). Two of the most antibiotics-resistant isolates were further confirmed using 16S ribosomal RNA sequencing. A lytic phage was detected against the MRSA isolates tested In Vitro, namely vB_SauP_ASUmrsa123. The phage belonged to Rountreeviridae family based on morphological properties observed by TEM and the host range of the isolated phage was tested on the 25 clinical MRSA isolates in Vitro. The one-step growth curve of the isolated phage showed that the latent period was about 55 min, and the burst size was estimated at 167 PFU. The whole genome sequencing and annotation of genes revealed that phage vB_SauP_ASUmrsa123 contained a linear dsDNA with a size of about 17,155 bp with predicted 24 ORFs. Analysis of its genome provides valuable information approximately the variety of phages belonging to the staphylococcal phages class I. Conclusion: A lytic Podo Phage vB_SauP_ASUmrsa123 was identified against S. aureus MRSA isolates and its genome was sequenced. The phage was found to be eligible for potential application in biocontrol. [ABSTRACT FROM AUTHOR]

Diabetic wounds pose a challenge to healing due to increased bacterial susceptibility and poor vascularization. Effective healing requires simultaneous bacterial and biofilm elimination and angiogenesis stimulation. In this study, we incorporated polyaniline (PANI) and S-Nitrosoglutathione (GSNO) into a polyvinyl alcohol, chitosan, and hydroxypropyltrimethyl ammonium chloride chitosan (PVA/CS/HTCC) matrix, creating a versatile wound dressing membrane through electrospinning. The dressing combines the advantages of photothermal antibacterial therapy and nitric oxide gas therapy, exhibiting enduring and effective bactericidal activity and biofilm disruption against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Furthermore, the membrane's PTT effect and NO release exhibit significant synergistic activation, enabling a nanodetonator-like burst release of NO through NIR irradiation to disintegrate biofilms. Importantly, the nanofiber sustained a uniform release of nitric oxide, thereby catalyzing angiogenesis and advancing cellular migration. Ultimately, the employment of this membrane dressing culminated in the efficacious amelioration of diabetic-infected wounds in Sprague–Dawley rats, achieving wound closure within a concise duration of 14 days. Upon applying NIR irradiation to the PVA-CS-HTCC-PANI-GSNO nanofiber membrane, it swiftly eradicates bacteria and biofilm within 5 min, enhancing its inherent antibacterial and anti-biofilm properties through the powerful synergistic action of PTT and NO therapy. It also promotes angiogenesis, exhibits excellent biocompatibility, and is easy to use, highlighting its potential in treating diabetic wounds. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa (Pa) and Methicillin susceptible Staphylococcus aureus (MSSA) are the predominant bacteria found in the airways of people with cystic fibrosis (pwCF), significantly contributing to lung disease progression. While various factors influencing the initial acquisition (IA) of these pathogens are known, the impact of environmental conditions remains understudied. This epidemiological study assessed the risk of MSSA and Pa initial acquisitions in relation to seasonality and climatic zones among 1,184 French pwCF under 18 years old. The age at IA for Pa (Pa-IA) and MSSA (MSSA-IA) was estimated using the Kaplan–Meier method. Seasonality and climatic zones were analysed as risk factors using time-varying Cox regression models. The median age at MSSA-IA was notably earlier (2.0 years) than that at Pa-IA (5.1 years). MSSA-IA occurred increasingly younger in more recent birth cohorts, while the age at Pa-IA remained stable over time. The risk of Pa-IA was consistently higher in all seasons compared with spring, peaking in autumn (HR = 1.53), irrespective of climatic zones. In Oceanic and Continental climates, the highest risk for MSSA-IA was in winter (HRs = 1.45 and 1.20 respectively). In the Mediterranean climate, the risk of MSSA-IA was lower in winter compared to spring (HRs = 0.68 and 0.61 respectively), and the median age at MSSA-IA later than for Pa-IA. This study demonstrates that seasonality and meteorological factors may influence acquisition of MSSA and Pa in pwCF. These findings suggest that environmental factors play a role in pathogen acquisition dynamics in CF and could inform the development of preventive strategies. [ABSTRACT FROM AUTHOR]

Osteomyelitis (OM) is an inflammatory disease of bone infection and destruction characterized by dysregulation of bone homeostasis. Staphylococcus aureus (SA) has been reported to be the most common pathogen causing infectious OM. Recent studies have demonstrated that N6-methyladenosine (m6A) regulators are associated with the development of OM. However, the molecular mechanism of m6A modifications in OM remains unclear. Here, we investigated the function of methyltransferase-like 3 (METTL3)-mediated m6A modification in OM development. In this study, human bone mesenchymal stem cells (hBMSCs) were treated with staphylococcal protein A (SpA), a vital virulence factor of SA, to construct cell models of OM. Firstly, we found that METTL3 was upregulated in OM patients and SpA-induced hBMSCs, and SpA treatment suppressed osteogenic differentiation and induced oxidative stress and inflammatory injury in hBMSCs. Functional experiments showed that METTL3 knockdown alleviated the inhibition of osteogenic differentiation and the promotion of oxidative stress and inflammation in SpA-treated hBMSCs. Furthermore, METTL3-mediated m6A modification upregulated miR-320a expression by promoting pri-miR-320a maturation, and the mitigating effects of METTL3 knockdown on SpA-mediated osteogenic differentiation, oxidative stress and inflammatory responses can be reversed by miR-320 mimic. In addition, we demonstrated that phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) was a downstream target of miR-320a, upregulation of PIK3CA alleviated miR-320a-induced inhibition of osteogenic differentiation, and upregulation of oxidative stress and inflammatory responses during SpA infection. Finally, we found that silencing METTL3 alleviated OM development by regulating the miR-320a/PIK3CA axis. Taken together, our data demonstrated that the METTL3/m6A/miR-320a/PIK3CA axis regulated SpA-mediated osteogenic differentiation, oxidative stress, and inflammatory responses in OM, which may provide a new therapeutic strategy for OM patients. [ABSTRACT FROM AUTHOR]

Introduction: The buds of Lonicera japonica Thunb. var. chinensis (Wats.) Bak, commonly named red honeysuckle, have attracted attention because of their bright colors. However, owing to the lack of systematic studies, the potential applications of red honeysuckle are not clear, and its development and utilization have not been well known. Methods: In this study, compared with the buds of L. japonica Thunb. (honeysuckle), the potential applications of red honeysuckle were explored based on biological activities, bio-active components, and sensory flavor combined with widely targeted metabolomics. Results: As a result, in vitro tests showed that it had a stronger antioxidant and a stronger inhibitory effect on the growth of Escherichia coli and Staphylococcus aureus. There was no cytotoxicity on LPS-induced RAW264.7 cells in its aqueous extract using the CCK-8 method. Moreover, it also had a stronger effect on inhibiting the expression of inflammatory factors such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). The content of its bio-active components chlorogenic acid and cynaroside was significantly higher (p ≤ 0.001) than that of green honeysuckle. Widely targeted metabolomics analysis revealed that 4 volatile metabolites, such as (E)-4-hexene-1-ol and pyrazole, and 21 non-volatile metabolites, such as macranthoside B and oleanolic acid-3- O -glc(1-2)-(ara)-28- O -glucoside ester, were specific in red honeysuckle. Interestingly, 14 specific terpenoid metabolites were triterpenoid saponins, indicating a stronger biological activity in red honeysuckle. The sensory flavor analysis showed that the red honeysuckle had a stronger herbal and lighter floral flavor. Discussion: In conclusion, red honeysuckle had great development value with potential applications in medicines, foods, beverages, pigment additives, and health products. [ABSTRACT FROM AUTHOR]

Background: Daptomycin non-susceptible Staphylococcus aureus (DNS) strains pose a serious clinical threat, yet their characteristics remain poorly understood. Methods: DNS derivatives were generated by exposing S. aureus strains to subinhibitory concentrations of daptomycin. Competition experiment and growth kinetics experiment were used to observe the growth of bacteria. Galleria mellonella larvae and mouse skin abscess models were used to observe the virulence of bacteria. Transmission electron microscopy (TEM), cytochrome C experiment and biofilm formation experiment were used to observe the drug resistance phenotype. And homologous recombination was used to study the role of mutations. Results: Phenotypic profiling of DNS strains revealed impaired growth, increased cell wall thickness, enhanced biofilm formation, reduced negative surface charge, and attenuated virulence compared to their wild-type strains. Whole genome sequencing identified mutations in mprF , cls2 , and saeR in DNS strains. Allelic replacement experiments validated the roles of MprF L341F and Cls2 F60S substitutions in augmenting daptomycin non-susceptibility in Newman. Deletion of saeR in the NewmanMprFL341F strain and complementation of saeR in the Newman-DNS strain did not directly alter daptomycin susceptibility. However, the deletion of saeR was found to enhance competitive fitness under daptomycin pressure. Conclusion: This work validates adaptive laboratory evolution (ALE) for modeling clinical DNS strains and uncovers contributions of mprF , cls2 , and saeR mutations to the adaptation and resistance mechanisms of S. aureus against daptomycin. These findings enrich our understanding of how S. aureus acquired resistance to daptomycin, thus paving the way for the development of more effective treatment strategies and offering potential molecular markers for resistance surveillance. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus can cause outbreaks and becomes multi-drug resistant through gene mutations and acquiring resistance genes. However, why S. aureus easily adapts to hospital environments, promoting resistance and recurrent infections, remains unknown. Here we show that a specific S. aureus lineage evolved from a clone that expresses the accessory gene regulator (Agr) system to subclones that reversibly suppressed Agr and caused an outbreak in the hospital setting. S. aureus with flexible Agr regulation shows increased ability to acquire antibiotic-resistant plasmids, escape host immunity, and colonize mice. Bacteria with flexible Agr regulation shows altered cytosine genomic methylation, including the decreased 5mC methylation in transcriptional regulator genes (pcrA and rpsD), compared to strains with normal Agr expression patterns. In this work, we discover how altered genomic methylation promotes flexible Agr regulation which is associated with persistent pathogen colonization in the hospital environment. In this study, authors examine Staphylococcus aureus adaptability in hospitals, highlighting how a lineage evolved to reversibly suppress Agr, enhancing antibiotic resistance and colonization. [ABSTRACT FROM AUTHOR]

Background: High-density lipoprotein cholesterol (HDL-C) is negatively associated with infectious diseases, but the relationship between HDL-C and nasal colonization of Staphylococcus aureus is unclear. Objective: To investigate the relationship between HDL-C and nasal colonization of Staphylococcus aureus. Methods: The cross-sectional study included 7731 participants from the 2001–2004 National Health and Nutrition Inspection Survey (NHANES) survey cycle who had complete data. After adjusting demographics and lifestyle, we used multivariate logistic regression to analyze the relationship between HDL-C and nasal colonization of Staphylococcus aureus. We also used restricted cubic splines (RCS) to analyze the nonlinear relationship between HDL-C and nasal colonization of Staphylococcus aureus. All the analyses adjusted the relevant covariates. Results: The mean of HDL-C in this study was 1.38 ± 0.64 mmol/L and the colonization rate of nasal colonization of Staphylococcus aureus was 26.2%. Both unadjusted model (OR = 0.71; 95%CI: 0.62–0.80; P < 0.001) and preliminary adjusted model (model 1: OR = 0.77; 95%CI: 0.67–0.89; P < 0.001) showed a significant negative correlation between HDL-C and nasal colonization of Staphylococcus aureus. After adjusting all variables in model 3, the relationship between HDL-C and nasal colonization of Staphylococcus aureus was still significant and negatively correlated (OR = 0.79; 95%CI: 0.69–0.92; P = 0.002). In addition, through RCS analysis, there was also a significant negative correlation between HDL-C and nasal colonization of Staphylococcus aureus (P for non-linear = 0.034). In subgroup analysis, only gender has a significant impact on this relationship (P for interaction = 0.013). In male, for each additional raising unit of HDL-C, the risk of nasal colonization of Staphylococcus aureus decreased by 38% (OR = 0.62, 95%CI: 0.49–0.79); in female, the relationship was no longer significant. We did not observe the interaction between all the other subgroup analysis results (P for interaction > 0.05). Conclusions: We found that HDL-C was negatively correlated with nasal colonization of Staphylococcus aureus, especially in male, even after adjusting for various variables. These findings provide valuable insights into the development of early intervention strategies in people at high risk of infectious diseases. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusionWhen chest tube drainage does not adequately resolve thoracic empyema, video assisted thoracoscopic surgery (VATS) is often needed. However, the proper duration of antibiotics after VATS is poorly defined. Consequently, the objective of this study was to evaluate if short antibiotic durations post-VATS was equally effective compared to longer durations.Patients with thoracic empyema treated with VATS were identified retrospectively by a query of the hospital billing database. The bacterial causes of the empyema were divided into 8 different categories while the antibiotic duration after VATS was divided into two groups which included antibiotics ˂ 14 days and antibiotics >14 days. The primary outcome measured was rates of empyema recurrence. Statistical comparisons were conducted between the antibiotic duration groups overall and when stratified based on the different bacterial causes.137 patients were included in this study with the main cause of empyema being culture negative empyema (37.2%) while alpha haemolytic Streptococcus spp. was the most cultured bacteria (26.3%). There was no statistical difference (p = 0.5168), in the rates of empyema recurrence, when short antibiotic durations (median 11.6 days)were compared to longer antibiotic durations (median 29.1 days)post-VATS. Nor was there a statistical difference in recurrence rates when stratifying based on bacterial cause.This study reinforces that antibiotic durations less than 14 days post-VATS are equally effective as prolonged antibiotic durations. However, to determine the proper duration of antibiotic therapy post-VATS, a prospective clinical trial is needed to reduce complications of prolonged antibiotic therapies for these patients. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) infections are prevalent in hospitals and often lead to significant health complications. This study aimed to explore the chemical composition of the aerial part of Crotalaria madurensis and evaluate its antioxidant and antibacterial properties. The impact of gamma irradiation on the antibacterial properties of the plant extract and metabolite 1 against MRSA was also examined. Fourier-transform infrared (FTIR) analysis was conducted on the filtrates of untreated MRSA and MRSA treated with the plant extract and metabolite 1. Four flavonol glycosides were identified as gossypetin 8-methoxy, 3-O-β-D-xylopyranoside (metabolite 1), gossypetin 8-O-β-D-glucopyranoside (metabolite 2), kaempferol 3-O-β-D-glucpyranoside (Astragalin, metabolite 3), and herbacetin 7-methoxy-3-O-β-D-glucopyranoside (metabolite 4). All metabolites exhibited significant antioxidant properties using different assays. The antibacterial efficacy of the extract and metabolite 1, which showed substantial antioxidant properties compared to the other isolated metabolites, was evaluated. Both the plant extract and metabolite 1 significantly reduced the viability and cell count of MRSA at concentrations of 1.0 and 0.5 mg/ml. The antibacterial activity of the plant extract and metabolite 1 was assessed after gamma irradiation at 50 and 100 Gy, which did not significantly affect the antibacterial efficiency. FTIR analysis indicated that the plant extract and metabolite 1 significantly altered the band frequency values, bandwidth, and peak intensity % of the treated MRSA filtrate. Molecular docking studies suggested that metabolite 1 exhibited the highest antioxidant and anti-MRSA activity, with strong binding scores like the ligand, indicating an effective interaction and high affinity between metabolite 1 and the target molecule. [ABSTRACT FROM AUTHOR]

The increasing prevalence of non-tuberculous mycobacterium (NTM) infections alongside tuberculosis (TB) underscores a pressing public health challenge. Yet, the mechanisms governing their infection within the lung remain poorly understood. Here, we integrate metagenomic sequencing, metabolomic sequencing, machine learning classifiers, SparCC, and MetOrigin methods to profile bronchoalveolar lavage fluid (BALF) samples from NTM/TB patients. Our aim is to unravel the intricate interplay between lung microbial communities and NTM/ Mycobacterium tuberculosis infections. Our investigation reveals a discernible reduction in the compositional diversity of the lung microbiota and a diminished degree of mutual interaction concomitant with NTM/TB infections. Notably, NTM patients exhibit a distinct microbial community characterized by marked specialization and notable enrichment of Pseudomonas aeruginosa and Staphylococcus aureus , driving pronounced niche specialization for NTM infection. Simultaneously, these microbial shifts significantly disrupt tryptophan metabolism in NTM infection, leading to an elevation of kynurenine. Mycobacterium intracellulare , Mycobacterium paraintracellulare , Mycobacterium abscessus , and Pseudomonas aeruginosa have been implicated in the metabolic pathways associated with the conversion of indole to tryptophan via tryptophan synthase within NTM patients. Additionally, indoleamine-2,3-dioxygenase converts tryptophan into kynurenine, fostering an immunosuppressive milieu during NTM infection. This strategic modulation supports microbial persistence, enabling evasion from immune surveillance and perpetuating a protracted state of NTM infection. The elucidation of these nuanced microbial and metabolic dynamics provides a profound understanding of the intricate processes underlying NTM and TB infections, offering potential avenues for therapeutic intervention and management. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a global challenge to the clinical field and food industry. Therefore, the development of antimicrobial photodynamic therapy (aPDT) has become one of the valuable methods to control this pathogen. The antibacterial activity of photoinactivation by erythrosine (Ery) against S. aureus has been reported, but its modes of action are unclear. This study aimed to employ a proteomic approach to analyze modes of action of Ery‐aPDT against S. aureus. We determined the antibacterial effect by Ery‐aPDT assays, quantified reactive oxygen species (ROS) and injury to the cell membrane, and determined protein expression using a proteomic approach combined with bioinformatic tools. Ery‐aPDT was effective in reducing S. aureus to undetectable levels. In addition, the increment of ROS accompanied the increase in the reduction of cell viability, and damage to cellular membranes was shown by sublethal injury. In proteomic analysis, we found 17 differentially expressed proteins. These proteins revealed changes mainly associated with defense to oxidative stress, energy metabolism, translation, and protein biosynthesis. Thus, these results suggest that the effectiveness of Ery‐aPDT is due to multi‐targets in the bacterial cell that cause the death of S. aureus. [ABSTRACT FROM AUTHOR]

Background: Urinary tract infections (UTIs) are a widespread and recurring health issue that is increasingly becoming a public health concern worldwide. Each year, approximately 150 million people experience UTIs, with over half of the population reporting having had at least one UTI in their lifetime, making it one of the most prevalent bacterial infections globally. One of the main bacterial problems facing public health today is Staphylococcus Aureus (S. Aureus), which is most common in those suffering from urinary tract infections. While S. aureus has been linked to 0.5-6% of urinary tract infections, untreated S. Aureus infections can result in serious, perhaps fatal conditions. The aim of this review is to examine how biofilm-forming S. aureus contributes to the pathogenesis of UTIs and its role in antibiotic resistance and recurrent infections. The review focuses on the mechanisms by which S. aureus biofilms exacerbate the persistence and severity of UTIs, especially in the context of multi-drug resistant strains, highlighting the challenges in treating catheter-associated urinary tract infections (CAUTI) and chronic bacterial prostatitis. Conclusions: In fact, because of its multi-drug resistant (MDR) forms, S. aureus has grown to be a global health concern. A significant contributing factor to recurrent urinary tract infections with increased resistance to antibiotics is the biofilm of S. Aureus. [ABSTRACT FROM AUTHOR]

Many researchers are focusing on screening the biological activities of plants owing to their safety and possible pharmacological actions. Consequently, we aimed to explore the antiproliferative and cytotoxic properties of Cycas media methanolic extract on HepG2 cell lines. Moreover, we also explore the antitumor action against the experimentally induced solid Ehrlich carcinoma (SEC) model and investigate the possible involved molecular mechanisms. Also, the antibacterial action of the extract was elucidated. Different concentrations of the extract were incubated with HepG2 to determine cytotoxicity, followed by cell cycle analysis. The in vivo experiment was accomplished by grouping the animals into four different groups (n = 10); normal control, SEC, C. media 100, and C. media 200. The extract was administered at 100 and 200 mg/kg. Tumor volume, tumor inhibition rate, toxicity profile, and antioxidant biomarkers were determined. Moreover, the PI3K/AKT/mTOR signaling pathway was investigated as a possible underlying antitumor mechanism. The tumor control group showed a remarkable upregulation for PI3K, p-AKT, and p-mTOR, along with downregulation for the antioxidant SOD and GPX4, as well as decreased levels of GSH and MDA. C. media extract reversed these parameters to a significant level and the higher dose showed a superior antitumor effect. C. media extract showed antiproliferative effects against HepG2 cells, along with a suppressive action on the PI3K/AKT/mTOR pathway and an antioxidant effect. Additionally, C. media had antibacterial consequences against S. aureus isolates with minimum inhibitory concentrations from 32 to 128 µg/mL. It also caused a noteworthy growth delay as well as a notable reduction in the membrane integrity of S. aureus isolates. These beneficial outcomes suggest C. media to have potential antitumor and antibacterial activities. [ABSTRACT FROM AUTHOR]

Purpose: We aim to evaluate the association between central venous catheter (CVC) insertion site and microbiological CVC complications in a nationwide cohort. Methods: This study was conducted using the healthcare-associated infection surveillance cohort "REA-REZO" involving 193 intensive care units (ICUs). All CVC inserted and removed during the same ICU stay between January 1st 2018 and December 31st 2022 were eligible but only those whose tips were sent for microbiological analysis were included. Primary objective was to describe CVC insertion sites and subsequent catheter-related bloodstream infection (CRBSI). Results: Out of 126,997 CVCs, 71,314 were not sent for tip culture, and only 55,663 CVCs were included, (30,548 in internal jugular [IJ], 14,423 in femoral and 10,692 in subclavian [SC] sites). The incidence of CRBSI was 0.7 [0.6–0.8] in the IJ site, 0.7 [0.6–0.9] in the femoral site, and 0.6 [0.4–0.7] CRBSI per 1000 CVC days in the SC site (p = 0.248). The multivariable Poisson regression model showed no differences of CRBSI incidence rates between the three insertion sites. Microorganisms observed in CRBSI were coagulase-negative Staphylococci (27.9%), Enterobacterales (27.5%), non-fermenting Gram-negative Bacilli (10.4%), Candida sp. (16.9%), and Staphylococcus aureus (16.9%). Conclusion: Low CRBSI incidence rates were reported. CRBSI incidences rates were similar in the three insertion sites. Uncertainty remains due to potential selection bias since many CVCs had to be excluded. [ABSTRACT FROM AUTHOR]

Objectives: Investigate whether and which synoviocytes would acquire trained immunity characteristics that could exacerbate joint inflammation following a secondary Staphylococcus aureus infection. Methods: Lipopolysaccharide (LPS) and S. aureus were separately or double injected (21 days of interval) into the tibiofemoral joint cavity of male C57BL/6 mice. At different time points after these stimulations, mechanical nociception was analyzed followed by the analysis of signs of inflammation and damage in the affected joints. The trained immunity markers, including the glycolytic and mTOR pathway, were analyzed in whole tissue or isolated synoviocytes. A group of mice was treated with Rapamycin, an mTOR inhibitor before LPS or S. aureus stimulation. Results: The double LPS – S. aureus hit promoted intense joint inflammation and damage compared to single joint stimulation, including markers in synoviocyte activation, production of proinflammatory cytokines, persistent nociception, and bone damage, despite not reducing the bacterial clearance. The double LPS - S. aureus hit joints increased the synovial macrophage population expressing CX3CR1 alongside triggering established epigenetic modifications associated with trained immunity events in these cells, such as the upregulation of the mTOR signaling pathway (p-mTOR and HIF1α) and the trimethylation of histone H3. Mice treated with Rapamycin presented reduced CX3CR1+ macrophage activation, joint inflammation, and bone damage. Conclusions: There is a trained immunity phenotype in CX3CR1+ synovial macrophages that contributes to the exacerbation of joint inflammation and damage during septic arthritis caused by S. aureus. [ABSTRACT FROM AUTHOR]

Introduction: Paediatric CSF shunt infection rate remains a well-known complication that is not only responsible of potentially severe sequels for patients but also for economical expenses. In that study, we questioned if it is possible to attain the zero percent rate of infection that should be the goal of every paediatric neurosurgeon. Methods: We report our series of patients treated with a CSF device from January the first 2016 to December 31 2018. Results: In all 147 patients treated for hydrocephalus, the follow-up was of at least of 2 years from the implantation. Antibiotic-coated tubes were always used with a differential pressure valve system. A total of 172 surgical procedures were performed for 147 patients. In the follow-up time period, 4 patients presented a post-operative infection (2.3%). Two infections appeared early after the surgical procedure one after 24 h and the other after 6 days; the other two infections were diagnosed after 53 days and the other after 66 days. The germs responsible of the infections were a Staphylococcus capitals, an Escherichia coli, a Klebsiella pneumonia, and a Staphylococcus aureus. Conclusions: Shunts will always be implanted especially in new-borns and for particular aetiologies of hydrocephalus. To reduce the rate of infection, the best thing to do is to adopt adapted protocols. Our low incidence of infection rate for shunts represent a long history to research preventive factors that helped us to improve our results during the time. [ABSTRACT FROM AUTHOR]

In the competition between the pathogen infection and the host defense, infectious microorganisms may enter the host cells by evading host defense mechanisms and use the intracellular biomolecules as replication nutrient. Among them, intracellular Staphylococcus aureus relies on the host cells to protect itself from the attacks by antibiotics or immune system to achieve long-term colonization in the host, and the consequent clinical therapeutic failures and relapses after antibiotic treatment. Here, we demonstrate that intracellular S. aureus surviving well even in the presence of vancomycin can be effectively eliminated using an emerging cell-mimicking therapeutic strategy. These cell mimics with natural killer cell-like activity (NKMs) are composed of a redox-responsive degradable carrier, and perforin and granzyme B within the carrier. NKMs perform far more effectivly than clinical antibiotics in treating intracellular bacterial infections, providing a direct evidence of the NK cell-mimicking immune mechanism in the treatment of intracellular S. aureus. [ABSTRACT FROM AUTHOR]

Objectives Osteoarticular infection (OAI) is a feared complication of Staphylococcus aureus bacteraemia (SAB) and is associated with poor outcomes. We aimed to explore the risk of OAI and death following SAB in patients with and without rheumatoid arthritis (RA) and to identify risk factors for OAI in patients with RA. Methods Danish nationwide cohort study of all patients with microbiologically verified first-time SAB between 2006–18. We identified RA, SAB, comorbidities, and RA-related characteristics (e.g. orthopaedic implants and antirheumatic treatment) in national registries including the rheumatology registry DANBIO. We estimated the cumulative incidence of OAI and death and adjusted hazard ratios (HRs, multivariate Cox regression). Results We identified 18 274 patients with SAB (n  = 367 with RA). The 90-day cumulative incidence of OAI was 23.1% (95% CI 18.8; 27.6) for patients with RA and 12.5% (12.1; 13.0) for patients without RA (non-RA) [HR 1.93 (1.54; 2.41)]. For RA patients with orthopaedic implants cumulative incidence was 29.4% (22.9; 36.2) [HR 1.75 (1.08; 2.85)], and for current users of tumor necrosis factor inhibitors (TNFi) it was 41.9% (27.0; 56.1) [HR 2.27 (1.29; 3.98) compared with non-users]. All-cause 90-day mortality following SAB was similar in RA [35.4% (30.6; 40.3)] and non-RA [33.9% (33.2; 34.5), HR 1.04 (0.87; 1.24)]. Conclusion Following SAB, almost one in four patients with RA contracted OAI corresponding to a doubled risk compared with non-RA. In RA, orthopaedic implants and current TNFi use were associated with approximately doubled OAI risk. One in three died within 90 days in both RA and non-RA. These findings encourage vigilance in RA patients with SAB to avoid treatment delay of OAI. [ABSTRACT FROM AUTHOR]

We investigated whether injecting drug use was a risk factor for methicillin resistance among inpatients with Staphylococcus aureus bloodstream infections (SABSIs) at an Australian health service. In 273 inpatients, 46 (16.9%) of SABSIs were methicillin‐resistant S. aureus (MRSA). MRSA was more frequent in those who had injected drugs in the past 6 months (20.6%) compared with other inpatients (15.7%). Injecting drug use was associated with a 4.82‐fold (95% confidence interval = 1.54–16.29) increased odds of MRSA after accounting for confounders. [ABSTRACT FROM AUTHOR]

Background Although a significant number of cases of Staphylococcus aureus bacteraemia (SAB) are managed at non-referral community hospitals, the impact of a bundle-of-care intervention in this setting has not yet been explored. Methods We performed a quasi-experimental before–after study with the implementation of a bundle of care for the management of SAB at five non-referral community hospitals and a tertiary care university hospital. Structured recommendations for the five indicators selected to assess quality of care were provided to investigators before the implementation of the bundle and monthly thereafter. Primary endpoints were adherence to the bundle intervention and treatment failure, defined as death or relapse at 90 days of follow-up. Results One hundred and seventy patients were included in the pre-intervention period and 103 in the intervention period. Patient characteristics were similar in both periods. Multivariate analysis controlling for potential confounders showed that performance of echocardiography was the only factor associated with improved adherence to the bundle in the intervention period (adjusted OR 2.13; 95% CI 1.13–4.02). Adherence to the bundle, performance of follow-up blood cultures, and adequate duration of antibiotic therapy for complicated SAB presented non-significant improvements. The intervention was not associated with a lower rate of 90 day treatment failure (OR 1.11; 95% CI 0.70–1.77). Conclusions A bundle-of-care intervention for the management of SAB at non-referral community hospitals increased adherence to quality indicators, but did not significantly reduce rates of 90 day mortality or relapse. [ABSTRACT FROM AUTHOR]

• Psidium species are traditionally used for various diseases. • P. guineense promoted high ability to reduce the virulence of Staphylococcus aureus. • Synergistic effect of P. guineense with antibiotics was evidenced. • In the present experiment, P. guineense demonstrates activity against all strains of S. aureus. Psidium guineense SW., commonly known as sour guava, is used in traditional medicine to address diverse health issues, such as inflammation, infections, and gastrointestinal disorders. Although previous research has highlighted the antimicrobial properties of the root extract and the antioxidant potential of its fruits, information regarding the activities associated with the leaf extract is lacking. The aim of the study was to use the traditional knowledge of the biological properties of P. guineense and investigate its antimicrobial activity, mechanism of action, synergistic effects, and antivirulence activity against Staphylococcus aureus. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined for S. aureus , including antibiotic-resistant isolates. The synergy between the extract and antibiotics was evaluated. A growth curve was constructed for S. aureus treated with the extract. The anti-hemolytic activity was assessed by inhibiting hemolysis in human blood, and the inhibition of staphyloxanthin (STX) was examined. The extract effectively inhibited all strains with MIC and MBC values ranging from 256 to 512 µg/mL and 512 to 1024 µg/mL, respectively. Antimicrobial synergy experiments demonstrated the enhanced effectiveness of antibiotics, especially ciprofloxacin, when combined with the P. guineense extract, especially with ciprofloxacin, resulting in complete synergy against all S. aureus strains. In growth curve tests, the extract inhibited growth at MIC of 256 µg/mL within 8 h and significantly delayed it at MIC/2 (128 µg/mL) within 12 h. In antivirulence tests, the extract effectively reduced hemolysis and STX production by S. aureus at MIC and MIC/2, indicating its potential as an antimicrobial agent with antivirulence properties. The extract effectively inhibited S. aureus , including drug-resistant strains with low MIC and MBC values, exhibiting strong antimicrobial and synergistic properties with antibiotics. also In addition, the extract accelerated recovery by limiting bacterial growth and exhibiting antivirulence capabilities, reducing the severe symptoms of S. aureus infections. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus generates extracellular membrane vesicles (MVs) during both in vitro culture and in vivo infection. S. aureus MVs are generated by either blebbing of the cytoplasmic membrane or explosive cell lysis. Proteins and nucleic acids encapsulated within S. aureus MVs are protected from degradation or neutralization by host factors. S. aureus MVs exhibit cytotoxicity to a variety of host cell types and induce both host innate and adaptive immune responses in animal infection models. MVs exploit different endocytic pathways for the delivery of their cargo into host cells. Deciphering the intracellular fate of S. aureus MVs after cellular entry may deepen our limited understanding of how MVs impact the host during staphylococcal infections. Staphylococcus aureus is an important bacterial pathogen that causes a wide variety of human diseases in community and hospital settings. S. aureus employs a diverse array of virulence factors, both surface-associated and secreted, to promote colonization, infection, and immune evasion. Over the past decade, a growing body of research has shown that S. aureus generates extracellular membrane vesicles (MVs) that package a variety of bacterial components, many of which are virulence factors. In this review, we summarize recent advances in our understanding of S. aureus MVs and highlight their biogenesis, cargo, and potential role in the pathogenesis of staphylococcal infections. Lastly, we present some emerging questions in the field. [ABSTRACT FROM AUTHOR]

The antibacterial and antibiofilm effects of rosehip vinegar and propolis extract, separately and as a mixture, were investigated on Staphylococcus aureus and Escherichia coli O157:H7. The organoleptic properties and tissue integrity of sardine fish treated with this mixture were evaluated. The propolis extract was found to have a higher inhibitory effect (>80%) on S. aureus (up to the 5th dilution) than on E. coli O157:H7 (only at the first dilution). A potential synergistic antibacterial and antibiofilm effect of the mixture was observed with an inhibition ratio of ≥50%. This mixture may extend the shelf life of sardines as a natural antibacterial/antibiofilm preservative. [ABSTRACT FROM AUTHOR]

Background: Livestock-associated Staphylococcus aureus (LA-SA) has gained global attention because of its ability to colonize farm animals and transmit to the environment and humans, leading to symptomatic infections and the spread of antimicrobial resistance (AMR). In the last decade, numerous studies have reported a high prevalence of S. aureus clonal complex (CC) 398 in pig farms. Results: In this study, 163 S. aureus isolates were collected from healthy pigs (n = 110), farm environments (n = 42), and farm workers (n = 11), and their AMR profiles and epidemiological characteristics were analyzed. We identified 51 (31.3%) methicillin-resistant S. aureus (MRSA) and 112 (68.7%) methicillin-susceptible S. aureus (MSSA), with 161 (98.8%) isolates belonging to the CC398 lineage. The highest prevalence of spa type t571 was observed among the CC398 isolates. All 47 sequence type (ST) 398 MRSA isolates carried staphylococcal cassette chromosome mec (SCCmec) V, while four ST541 isolates carried SCCmec IV. High levels of resistance to commonly used antibiotics, including phenicols, quinolones, lincosamides, macrolides, aminoglycosides, and tetracyclines, have been observed on Korean pig farms. Notably, 21 cfr-positive CC398 isolates (four ST541-SCCmec IV MRSA and 17 ST398 MSSA) displaying increased resistance to linezolid were identified in healthy pigs. Conclusions: In summary, these findings suggest that the multidrug-resistant CC398 S. aureus lineage predominantly colonizes healthy pigs and farm environments in Korea. The emergence of cfr-positive S. aureus at human-animal interfaces presents a significant threat to food safety and public health. [ABSTRACT FROM AUTHOR]

The presence of residual antibiotics and the excessive accumulation of metals beyond permissible limits in milk represent significant health challenges. This study aimed to analyse the levels of heavy metals and trace elements in raw milk from Kurdistan province using inductively coupled plasma mass spectrometry (ICP‐MS) following digestion via thermal block. Subsequently, the samples were evaluated for contamination with MRSA (methicillin‐resistant Staphylococcus aureus), taking into account the potential correlation between methicillin‐resistant strains and metal accumulation. Finally, milk safety was assessed based on the presence of toxic metals. A total of 180 milk samples were examined. Among them, 13.34% were found to be contaminated with S. aureus, and of those, 62.48% tested positive for MRSA. The metal concentrations (mg/kg) were measured as follows: arsenic 7 × 10−2 ± 6 × 10−3, cadmium 4.70 × 10−1 ± 9.70 × 10−2, lead 7 × 10−2 ± 5 × 10−3, mercury 3 × 10−2 ± 9 × 10−3 and iron 4 × 10−2 ± 9 × 10−3. Interestingly, arsenic, cadmium and iron levels were found to be correlated with the presence of MRSA. Additionally, there was an inverse relationship between toxic metals and essential ones in samples sensitive to methicillin (P < 0.001). The Target Hazard Quotient (THQ) for cadmium is indicated at 9.94. Furthermore, the calculated Carcinogenic Risk (CR) parameters for cadmium and arsenic were 6.06 × 10−3 and 2.22 × 10−4, respectively, suggesting that their concentrations fall within the carcinogenic range. The coexistence of MRSA and metal contamination in raw milk highlights the potential risks linked to its consumption. Consequently, the adoption of rigorous hygiene protocols is imperative to effectively address these concerns. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD), a prevalent Th2-dominant skin disease, involves complex genetic and environmental factors, including mutations in the Filaggrin gene and dysbiosis of skin microbiota characterized by an increased abundance of Staphylococcus aureus. Our recent findings emphasize the pivotal role of the skin barrier's integrity and microbial composition in infantile AD and allergic diseases. Early skin dysbiosis predisposes infants to AD, suggesting targeted skincare practices as a preventive strategy. The effects of skincare interventions, particularly the application of moisturizers with the appropriate molar concentration of ceramides, cholesterol, and fatty acids, play a crucial role in restoring the skin barrier. Notably, our study revealed that appropriate skincare can reduce Streptococcus abundance while supporting Cutibacterium acnes presence, thus directly linking skincare practices to microbial modulation in neonatal skin. Despite the mixed outcomes of previous Randomized Controlled Trials on the efficacy of moisturizers in AD prevention, our research points to the potential of skincare intervention as a primary preventive method against AD by minimizing the impact of genetic and environmental factors. Furthermore, our research supports the notion that early aggressive management of eczema may reduce the incidence of food allergies, highlighting the necessity for multifaceted prevention strategies that address both the skin barrier and immune sensitization. By focusing on repairing the skin barrier and adjusting the skin's microbiome from birth, we propose a novel perspective on preventing infantile AD and allergic diseases, opening new avenues for future studies, and practices in allergy prevention. [ABSTRACT FROM AUTHOR]

Purpose An advisory panel of experts was convened by the ASHP Foundation as a part of its Medication-Use Evaluation Resources initiative to provide commentary on an approach to antibiotic stewardship in the treatment of skin and soft tissue infections (SSTIs), with a focus on oral antibiotics in the emergency department (ED) setting for patients who will be treated as outpatients. Considerations include a need to update existing guidelines to reflect new antibiotics and susceptibility patterns, patient-specific criteria impacting antibiotic selection, and logistics unique to the ED setting. Summary While national guidelines serve as the gold standard on which to base SSTI treatment decisions, our advisory panel stressed that institutional guidelines must be regularly updated and grounded in local antimicrobial resistance patterns, patient-specific factors, and logistical considerations. Convening a team of experts locally to establish institution-specific guidelines as part of a comprehensive antibiotic stewardship program can ensure patients receive the most appropriate oral therapy for the outpatient treatment of SSTIs in patients visiting the ED. Conclusion SSTI treatment considerations for antibiotic selection in the ED supported by current, evidence-based guidelines, including guidance on optimal oral antibiotic selection for patients discharged for outpatient treatment, are a useful tool to improve the quality and efficiency of care, enhance patient-centric outcomes and satisfaction, decrease healthcare costs, and reduce overuse of antibiotics. [ABSTRACT FROM AUTHOR]

The purpose of this study was to establish a porcine model of urinary tract infection (UTI) with gram‐positive uropathogens. Ten female domestic pigs were experimentally inoculated with human UTI isolates of Enterococcus faecalis (n = 3), Staphylococcus saprophyticus (n = 3), or Staphylococcus aureus (n = 4) and followed with regular urine samples. Bladders and kidneys were aseptically removed at termination (5–7 days post infection) and assessed by gross pathology and bacterial enumeration. Enterococcus faecalis (n = 3 of 3) and S. aureus (n = 2 of 4) successfully colonized the pig bladders. Inoculation with S. saprophyticus never resulted in detectable bacteriuria. All infected pigs had cleared the infection spontaneously before termination. Surprisingly, three (of four) pigs inoculated with S. aureus led to spontaneous infection with opportunistic pathogens. Also, one pig colonized with E. faecalis resulted in spontaneous infection with E. coli. In conlusion, the pig supports experimental UTI with E. faecalis for up to 24 h but not prolonged infection. S. aureus and S. saprophyticus fails to cause UTI in pigs and other animals should be considered for studying these pathogens. [ABSTRACT FROM AUTHOR]

The ethyl acetate, ethanol, methanol, and water extracts of cypress from three Tunisian regions (Bizerte, Ben Arous, and Nabeul) were reported for their phenolic content, antioxidant, and antibacterial activities. Cypress extract had an important antiradical and antibacterial potential which was strongly related to the organoleptic quality of the extract which appeared strongly region dependent. The highest contents of polyphenols were obtained in the methanol extract at the region of Bizerte (315.75 mg GAE/g DW). Cupressuflavone was the major compound with high proportions in methanol extract of Bizerte (68%). Amentoflavone also constituted an important flavonoid compound presented in higher proportion in the ethyl acetate extract of Ben Arous (21.2%). For Gram-positive bacteria strains, Staphylococcus aureus was sensitive to the ethanol extract of Nabeul with IZ = 40 mm. This study suggests cypress as potential natural source of antioxidants and antibacterial agents. [ABSTRACT FROM AUTHOR]