Deep Neck Cellulitis, Myositis, and Reactive Lymphadenitis Secondary to Rothia dentocariosa in an Immunocompetent Female: A Case Report.

Rothia dentocariosa is a commensal organism that is typically found in the oropharyngeal and respiratory tracts, and it typically possesses a low virulence profile, especially for immunocompetent patients. The case presented here represents an extremely rare case of deep neck cellulitis, myositis, and reactive lymphadenitis secondary to R. dentocariosa in an immunocompetent female. A 35-year-old female with no significant past medical history presented to the emergency department with neck pain with reduced range of motion, fever, chills, sinus congestion, and headache for one day. After a thorough workup, blood cultures grew R. dentocariosa in the days following admission. The patient subsequently recovered without any notable sequelae after proper antibiotic treatment. Since Rothia species are currently considered a low-virulence organism that typically causes endocarditis in immunocompromised hosts, this case should serve as a reference for its possible virulence level in immunocompetent hosts. In spite of this organism's pathological rarity, this case highlights the importance of understanding the microbiology, historical context, and treatment for R. dentocariosa as a cause for deep neck cellulitis, myositis, and reactive lymphadenitis.

Effect of allogeneic pure platelet-rich plasma, sodium cloxacillin, and their combination for the treatment of subclinical mastitis in crossbred cows.

Introduction: Bovine subclinical mastitis (SCM) caused by Gram-positive bacteria is a major cause of economic loss in the dairy industry, exacerbated in situations where antimicrobial resistance is present. Pure platelet-rich plasma (P-PRP) may be a therapeutic alternative for SCM, when used alone or with antibiotics, such as sodium cloxacillin (SC). This study aimed 1) to evaluate the therapeutic efficacy of allogeneic P-PRP, SC, and their combination (P-PRP+SC) in cows with SCM caused by Staphylococcus aureus and by streptococci (Staphylococcus aureus and S. dysgalactiae); 2) to determine the concentrations of somatic cells (SCC), interleukin 1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α) and TGF-ß1 in milk samples of the cows. Methods: 130 cows from 4 dairy herds completed the study, of which 40 cows were treated with P-PRP (10 mL), 28 cows with SC (5g), 36 with P-PRP+SC (10mL/5g), and 26 did not receive no treatment (negative control group, NCG). Results: The overall bacteriological cure was observed in 10/40 (25%) cows in the P-PRP group, 9/28 (32.14%) animals in the SC group, 26/36 (72.22%) cows in the P-PRP+SC group, and 10/26 (38.46%) animals in the NCG. SCM caused by S. aureus (82/130, 63.08%), was cured in 6/24 (25%) cows treated with P-PRP, 7/24 (29.2%) cows treated with SC, 8/16 (50%) animals treated with P-PRP+SC, and in 8/18 (44.4%) cows in NCG. For SCM caused by the streptococci (48/130, 36.91%), the cure was achieved in 4/12 (33.3%) cows treated with P-PRP, 2/4 (50%) cows treated with SC, 18/20 (90%) cows treated with P-PRP+SC, and in 2/8 (25%) cows of the NCG. SCC was significantly (p < 0.001) affected by the treatment, herd, cure, bacteria group, and number of calvings factors. IL-1ß milk concentrations were significantly (p < 0.001) influenced by treatment and farm factors, and the interaction between these factors. TNF-α milk concentrations were significantly (p < 0.001) influenced by time factor. TGF-ß1 milk concentrations were significantly affected by the time and cure factors. Conclusion: The combination of P-PRP and SC showed the best therapeutic response (90%) against bovine SCM caused by streptococci. However, none of the treatments showed an effective therapeutic response against S. aureus.

Erysipelothrix rhusiopathiae bacteremia treated with linezolid.

Erysipelothrix rhusiopathiae is a common zoonotic pathogen that rarely causes diseases in humans. It has three main disease manifestations: localized cutaneous, disseminated cutaneous, and a systemic form of infections, typically characterized as bacteremia with or without endocarditis. Human infections are often associated with occupational exposure to animals, animal products, or their excreta. We present a case of a 60-year-old woman found to have E. rhusiopathiae bacteremia associated with a leg laceration sustained after she fell into a sewer drain. Germane animal exposures were not identified; thus, the source of bacterium was attributed to sewage or sewage-contaminated water. She was initially treated with intravenous penicillin with clinical improvement. However, given the patient's social factors, prolonged oral antimicrobial therapy was considered. E. rhusiopathiae is routinely susceptible to penicillin, cephalosporins, and fluoroquinolones but resistant to vancomycin. The data on alternatives to beta-lactam therapy are limited. We report a case of E. rhusiopathiae bacteremia successfully treated with oral linezolid.

A promising eco-friendly and cost-effective photocatalytic rolled graphene oxide/poly(m-methylaniline) core-shell nanocomposite for antimicrobial action.

A new and innovative rolled graphene oxide (roll-GO)/poly-m-methylaniline (PmMA) core-shell nanocomposite has been successfully synthesized using an in situ polymerization technique. This eco-friendly and cost-effective material shows great promise due to its antimicrobial properties. The characterization of the nanocomposite involved X-ray diffraction and Fourier transform infrared spectroscopy to analyze its structure and functional groups, whereas scanning electron microscopy and transmission electron microscopy (TEM) were utilized to examine its morphology. TEM analysis revealed the formation of roll-GO, forming multi-walled tubes with inner and outer diameters of 50 and 70 nm, respectively. Optical analysis demonstrated an enhanced bandgap in the nanocomposite, with bandgap values of 2.38 eV for PmMA, 2.67 eV for roll-GO, and 1.65 eV for roll-GO/PmMA. The antibacterial efficacy of the nanocomposite was tested against Gram-positive bacteria, including Bacillus subtilis and Staphylococcus aureus, as well as Gram-negative bacteria such as Escherichia coli and Salmonella sp. The well diffusion method was used to determine the inhibition zones, revealing that the nanocomposite demonstrated broad-spectrum antibacterial activity against all the pathogens tested. The largest inhibition zones were observed for B. subtilis, followed by S. aureus, E. coli, and Salmonella sp. Notably, the inhibition zones increased when the samples were exposed to light compared to dark conditions, with increases of 33 and 18 mm noted for B. subtilis. This enhanced activity under light exposure is attributed to the photocatalytic properties of the nanocomposite. The antibacterial mechanism is based on both adsorption and degradation processes. Moreover, antibacterial activity was found to increase with increasing concentrations of nanoparticles, ranging from 100 to 500 ppm. This suggests that the nanocomposite has potential as an alternative to antibiotics, especially considering the growing issue of bacterial resistance. The promising results obtained from the inhibition zones make these nanocomposites suitable for various applications. Currently, the research team is working on the development of a prototype utilizing these antimicrobial particles within commercial bottles for sterilization purposes in factories and companies.

Effective RNA isolation method for gram-positive and acid-fast bacteria: metamorphosed from conventional RNA isolation techniques.

The RNA-based study provides an excellent indication of an organism's gene expression profile. Obtaining high-yield and high-purity RNA from Gram-positive and acid-fast bacteria is difficult without high-end kits and facilities. We optimised effective and simple protocol for RNA isolation that is a combination of enzymatic, physical and chemical treatment to disrupt cells. We successfully isolated high quality intact total RNA with yields ranging from 23.13 ± 0.40 to 61.51 ± 0.27 µg and the 260/280 purity ratio of 1.95 ± 0.01 to 2.05 ± 0.01 from Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Mycobacterium smegmatis. These results represents a significantly enhanced yield and purity compared to other combination of techniques which we performed. Compared to previous studies the yield obtained by this method is high for the studied organisms. Furthermore the yielded RNA was successfully used for downstream applications such as quantitative real time PCR. The described method can be easily optimised and used for various bacteria.

Evaluation of the activity of antimicrobial peptides against bacterial vaginosis.

New drugs for the treatment of bacterial vaginosis (BV) are yet to be developed due to concerns that they may contribute to the increase in antibiotic resistance in BV. Antimicrobial peptides (AMPs) are one of the most promising options for next-generation antibiotics. In this study, we investigated the bacteriostatic activity of the AMPs Pexiganan, plectasin, melittin, and cathelicidin-DM against Gram-negative and Gram-positive bacteria both in vitro and in a mouse model of BV infection. The results showed that Pexiganan, melittin, and cathelicidin-DM had significant antibacterial activity against both Gram-negative and Gram-positive bacteria. AMPs have great potential for clinical application in the treatment of vaginitis, and this study provides an experimental basis for their use in the active immunoprophylaxis of BV.

A systematic review of diabetic foot infections: pathogenesis, diagnosis, and management strategies.

Background: Diabetic foot infection represents a significant complication of diabetes mellitus, contributing substantially to morbidity, mortality, and healthcare expenditure worldwide. Accurate diagnosis relies on a comprehensive assessment integrating clinical evaluation, imaging studies, and microbiological analysis. Management necessitates a multidisciplinary approach, encompassing surgical intervention, antimicrobial therapy, and advanced wound care strategies. Preventive measures are paramount in reducing the incidence and severity, emphasizing patient education, regular foot screenings, and early intervention. Methods: The researchers performed a systematic review of literature using PUBMED MESH keywords. Additionally, the study was registered in the International Prospective Register of Systematic Reviews at the Center for Reviews and Dissemination, University of York (CRD42021277788). This review provides a comprehensive overview of the microbial spectrum and antibiotic susceptibility patterns observed in diabetic foot infections. Results: The search through the databases finally identified 13 articles with 2545 patients from 2021 to 2023. Overall, the predominant Gram-positive microbial species isolated were Staphylococcus aureus, Enterococcus fecalis, Streptococcus pyogenes, Streptococcus agalactiae, and Staphylococcus epidermidis. Whereas the predominant Gram-negative included Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Pseudomonas aeruginosa. Conclusion: Diabetic foot infections represent a complex and multifaceted clinical entity, necessitating a holistic approach to diagnosis, management, and prevention. Limited high-quality research data on outcomes and the effectiveness of guideline recommendations pose challenges in updating and refining existing DFI management guidelines. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021277788, identifier CRD42021277788.

Mystery of the Passerini Reaction for the Synthesis of the Antimicrobial Peptidomimetics against Nosocomial Pathogenic Bacteria.

The first example of applying salicylaldehyde derivatives, as well as coumarin with the formyl group at the C8 position in its structure, as carbonyl partners in a three-component Passerini reaction, is presented. As a result of research on the conditions of the Passerini reaction, the important role of the hydroxyl group in the salicylaldehyde used in the course of the multicomponent reaction was revealed. When an aldehyde with an unprotected hydroxyl group is used, only two-component α-hydroxy amide products are obtained. In contrast, the use of acylated aldehyde results in three-component α-acyloxy amide products with high efficiency. The developed protocol gives access to structurally diversified peptidomimetics with good yield. The compounds were also evaluated as antimicrobial agents against selected strains of nosocomial pathogenic bacteria. The structure-activity relationship revealed that inhibitory activity is strongly related to the presence of the trifluoromethyl group (CF3) or the methyl group at the C4 position in an unsaturated lactone ring of the coumarin scaffold. MIC and MBC studies were carried out on eight selected pathogenic bacteria strains (Gram-positive pathogenic Staphylococcus aureus strain (ATCC 23235), as well as on Gram-negative E. coli (K12 (ATCC 25404), R2 (ATCC 39544), R3 (ATCC 11775), and R4 (ATCC 39543)), Acinetobacter baumannii (ATCC 17978), Pseudomonas aeruginosa (ATCC 15442), and Enterobacter cloacae (ATCC 49141) have shown that the tested compounds show a strong bactericidal effect at low concentrations. Among all agents investigated, five exhibit higher antimicrobial activity than those observed for commonly used antibiotics. It should be noted that all the compounds tested showed very high activity against S. aureus, which is the main source of nosocomial infections that cause numerous fatalities. Additionally, the cytotoxicity of sixteen derivatives was measured with the use of the MTT test on BALB/c3T3 mouse fibroblast cell lines. The cytotoxicity studies revealed that the tested substances exert a similar or lower effect on cell proliferation than that observed for commonly used antibiotics within the range of therapeutic doses. A parallel MTT assay using ciprofloxacin, bleomycin, and cloxacillin showed that these antibiotics are more cytotoxic when tested in mammalian cells, and cell viability is in the range of 85.0-89.9%. Furthermore, we have shown that the studied coumarin-based peptidomimetics, depending on their structural characteristics, are nonselective and act efficiently against various Gram-positive and Gram-negative pathogens, which is of great importance for hospitalised patients.

The Therapeutic Effect of Contezolid in Complex Intra-Abdominal Infections.

Purpose: In this paper, we observed the use of contezolid in patients with complex intra-abdominal infections in the intensive care unit of the Hepatobiliary Surgery department at the Chinese PLA General Hospital. Patients and Methods: The study collected data on complex intra-abdominal infections patients who received the antibiotic contezolid between January 2022 and April 2023. Results: Contezolid was administered to 12 patients, including 8 with severe acute pancreatitis, 3 with intra-abdominal infections following abdominal surgery, and 1 with complicated intra-abdominal infection after trauma. Gram-positive bacteria, such as Enterococcus faecium, Enterococcus casseliflavus, Staphylococcus capitis, and Staphylococcus haemo-lytica, were detected in 11 patients. All patients who received contezolid had previously been treated with other anti-Gram-positive agents, including linezolid for 9 patients, teicoplanin for 6 patients, and vancomycin for 3 patients. The treatment with contezolid began 20.0 (15.0, 34.5) days after admission and lasted for 8.0 (6.0, 10.0) days. At the end of the treatment, the patients' body temperature showed a significant decrease. After concomitant therapy, IL-6 levels decreased, and platelet count increased. Conclusion: Contezolid has shown potential in treating complex intra-abdominal infections caused by Gram-positive bacteria by reducing fever and inflammatory response.

ESCMID/EUCIC clinical guidelines on preoperative decolonization and targeted prophylaxis in patients colonized by multidrug-resistant Gram-positive bacteria before surgery.

SCOPE: The aim of these guidelines is to provide recommendations on decolonization and perioperative antibiotic prophylaxis (PAP) in multidrug-resistant Gram-positive bacteria (MDR-GPB) adult carriers before inpatient surgery. METHODS: These European Society of Clinical Microbiology and Infectious Diseases (ESCMID)/European Committee on Infection Control (EUCIC) guidelines were developed following the systematic review of published studies targeting methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), methicillin-resistant coagulase-negative staphylococci (MR-CoNS) and pan-drug-resistant (PDR)-GPB. Critical outcomes were the occurrence of surgical site infections (SSIs) caused by the colonizing MDR-GPB and SSIs-attributable mortality. Important outcomes included the occurrence of SSIs caused by any pathogen, hospital-acquired infections, all-cause mortality, and adverse events associated with the interventions, including resistance development to the agents used and incidence of Clostridioides difficile infections. The last search of all databases was performed on November 1st, 2023. The level of evidence and strength of each recommendation were defined according to the GRADE approach. Consensus of a multidisciplinary expert panel was reached for the final list of recommendations. Antimicrobial stewardship considerations were included. RECOMMENDATIONS: The guideline panel reviewed the impact of decolonization, targeted PAP, and combined interventions (e.g., decolonization and targeted PAP) on the risk of SSIs and other outcomes in MDR-GPB carriers, according to the type of bacteria and type of surgery. We recommend screening for S. aureus (SA) before high-risk operations, such as cardiothoracic and orthopedic surgery. Decolonization with intranasal mupirocin with or without chlorhexidine bathing is recommended in patients colonized with SA before cardiothoracic and orthopedic surgery and suggested in other surgeries. Addition of vancomycin to standard prophylaxis is suggested for MRSA carriers in cardiothoracic surgery, orthopedic surgery, and neurosurgery. Combined interventions (e.g., decolonization and targeted prophylaxis) are suggested in MRSA carriers undergoing cardiothoracic and orthopedic surgery. No recommendation could be made regarding screening, decolonization, and targeted prophylaxis for VRE due to the lack of data. No evidence was retrieved for MR-CoNS and PDR-GPB. Careful consideration of the laboratory workload and involvement of antimicrobial stewardship as well as infection control teams are warranted before implementing screening procedures or performing changes in PAP policy. Future research should focus on novel decolonizing techniques, on the monitoring of resistance to decolonizing agents and PAP regimens, and on standardized combined interventions in high-quality studies.

Impact of Climate Change on Cellulitis: A Literature Review.

Climate change is a phenomenon that has had, and will continue to have, wide-ranging effects on the world in both the near and distant future. With regards to human health, research has demonstrated the impact of climate change on heat-related illness, mental health, and vector-borne infectious diseases. Through a review of the literature, this paper aims to elucidate both current and future consequences of climate change on cellulitis, a type of skin infection that is associated with significant morbidity, mortality, and cost. Factors such as elevated temperature, pollution, rising sea levels, and the increased frequency of natural disasters pose an alarming risk for the increased proliferation of infections such as cellulitis. Lastly, in light of these trends, this paper will address potential strategies individuals can implement to reduce the effects of climate change on cellulitis.

Deeply branching Bacillota species exhibit atypical Gram-negative staining.

The Gram staining method differentiates bacteria based on their cell envelope structure, with the monoderm and diderm cell envelope types traditionally being synonymous with Gram-positive and Gram-negative stain results, respectively. Monoderms have a single phospholipid membrane surrounded by a thick layer of peptidoglycan, while diderms have a lipopolysaccharide outer membrane exterior to a thin peptidoglycan layer. The Bacillota (formerly Firmicutes) phylum has members with both cell wall types, and recent phylogenetic analyses have shown that monoderm Bacillota evolved from diderm ancestors on multiple occasions. Here, we compiled Gram staining and ultrastructural data for Bacillota species with complete genomes to further investigate the evolution of Gram-positive and Gram-negative cell wall types. The results indicate that many deeply branching lineages at the root of Bacillota phylum stain Gram-negative but do not harbor genes for outer membrane protein or lipopolysaccharide biosynthesis. Phylogenetic reconstructions suggest that several deeply branching Bacillota species have retained a thin peptidoglycan layer in their cell walls, which was inherited from a diderm ancestor. Taxa with this atypical Gram-negative-staining cell wall structure include the thermophilic anaerobe Symbiobacterium thermophilum and members of the Desulfotomaculia, Syntrophamonadia, Desulfitobacteriia, Thermosediminibacteria, and Thermoanaerobacteria. Using Gram-staining results as a proxy for cell wall thickness, our analysis indicates that several independent peptidoglycan thickening events may have occurred in the evolution of the Gram-positive cell envelope. IMPORTANCE: In this study, we examined the evolution of bacterial cell envelopes, specifically focusing on Gram-positive and Gram-negative cell wall types in the Bacillota phylum. Our results indicate that certain bacteria can stain Gram-negative despite having a monoderm cell wall structure, thus challenging the conventional interpretation of Gram-staining results. Our observations also question the assumption that Gram-negative staining is always indicative of a diderm structure. These findings have broader implications for understanding how and when cell walls thicken during the evolution of bacterial cell envelopes.

Non-tunneled haemodialysis catheter-related blood stream infections and associated factors among first time haemodialysis patients: a prospective study from a tertiary care hospital in Sri Lanka.

BACKGROUND: A significant number of patients require non-tunneled haemodialysis catheters (NTHCs) in the event of an urgent need for immediate haemodialysis in developing countries. Catheter-related bloodstream infections (CRBSIs) are a major concern in haemodialysis, but there is a lack of local epidemiological data. This study aimed to determine the incidence of CRBSI, causative agents and associated risk factors in a tertiary care hospital in Sri Lanka. METHODS: A prospective study was conducted at the dialysis unit of Colombo South Teaching Hospital, Sri Lanka from December 2019 to August 2020. Adult patients who had haemodialysis for the first time with NTHCs were included. RESULTS: Of 149 dialysis patients (104-jugular vein and 45-femoral vein, mean age 58 ± 13.7 years, mean duration of catheterization 7.9 ± 3.4 days), the incidence of CRBSI was 13.58 per 1000 catheter days. Serum albumin levels, capillary blood sugar levels at admission, haemoglobin levels and duration of catheterization were significantly associated with CRBSI. Prescence of diabetes and patients with ESRD who started routine haemodialysis had a significantly higher risk of CRBSI. Gram-positive bacteria were the most common microorganisms associated with CRBSI (87.5%). CONCLUSIONS: Our results show high rates of infection with temporary vascular catheters in Sri Lanka, mainly due to Gram-positive bacteria. Diabetes mellitus, duration of catheterisation, low serum albumin, haemoglobin level and CBS on admission were identified as significant risk factors for CRBSI. Management strategies tailored to specific centers should be established in the nation to optimise catheter care and to monitor local microbiology for appropriate empirical antimicrobial treatment.

Effect of multifunctional cationic polymer coatings on mitigation of broad microbial pathogens.

Infection control measures to prevent viral and bacterial infection spread are critical to maintaining a healthy environment. Pathogens such as viruses and pyogenic bacteria can cause infectious complications. Viruses such as SARS-CoV-2 are known to spread through the aerosol route and on fomite surfaces, lasting for a prolonged time in the environment. Developing technologies to mitigate the spread of pathogens through airborne routes and on surfaces is critical, especially for patients at high risk for infectious complications. Multifunctional coatings with a broad capacity to bind pathogens that result in inactivation can disrupt infectious spread through aerosol and inanimate surface spread. This study uses C-POLAR, a proprietary cationic, polyamine, organic polymer with a charged, dielectric property coated onto air filtration material and textiles. Using both SARS-CoV-2 live viral particles and bovine coronavirus models, C-POLAR-treated material shows a dramatic 2-log reduction in circulating viral inoculum. This reduction is consistent in a static room model, indicating simple airflow through a static C-POLAR hanging can capture significant airborne particles. Finally, Gram-positive and Gram-negative bacteria are applied to C-POLAR textiles using a viability indicator to demonstrate eradication on fomite surfaces. These data suggest that a cationic polymer surface can capture and eradicate human pathogens, potentially interrupting the infectious spread for a more resilient environment. IMPORTANCE: Infection control is critical for maintaining a healthy home, work, and hospital environment. We test a cationic polymer capable of capturing and eradicating viral and bacterial pathogens by applying the polymer to the air filtration material and textiles. The data suggest that the simple addition of cationic material can result in the improvement of an infectious resilient environment against viral and bacterial pathogens.

Optimization of Experimental Infection of the Animal Model Galleria mellonella Linnaeus 1758 (Lepidoptera: Pyralidae) with the Gram-Positive Bacterium Micrococcus luteus.

The aim of this work was to develop an experimental protocol for the infection of Galleria mellonella with Gram-positive bacteria. Some physiological characteristics of these insects are comparable to those of vertebrates, therefore allowing the replacement of mammals in the preclinical phases of drug development. G. mellonella Linnaeus 1758 (Lepidoptera: Pyralidae) is accepted as an alternative model for the study of infectious diseases. Since data on infection procedures with different bacterial strains are scarce and sometimes conflicting, also due to different and non-uniform protocols, we developed an experimental protocol that would allow for controlled and repeatable infections, using the Gram-positive bacterium GRAS (Generally Regarded As Safe) Micrococcus luteus. After analyzing the morphology and defining the growth rate of M. luteus, doses of between 101 and 106 CFU/larvae were administered to late-stage larvae. The survival rate of the larvae was monitored up to 7 days and the LD50 determined. The bacterial clearance capacity of the larvae after injection with 103 and 105 CFU/larvae was assessed by hemolymph bacterial load analysis. The results made it possible to define the growth curve of M. luteus correlated with the CFU count; based on the LD50 (103.8 CFU/larvae) calculated on the survival of G. mellonella, infections were carried out to evaluate the immune efficiency of the larvae in bacterial clearance. This protocol, standardized on G. mellonella larvae, could provide a functional tool to study the course of bacterial infections.

Cubosome lipid nanocarriers for delivery of ultra-short antimicrobial peptides.

HYPOTHESIS: Although antimicrobial peptides (AMPs) are a promising class of new antibiotics, their inherent susceptibility to degradation requires nanocarrier-mediated delivery. While cubosome nanocarriers have been extensively studied for delivery of AMPs, we do not currently understand why cubosome encapsulation improves antimicrobial efficacy for some compounds but not others. This study therefore aims to investigate the link between the mechanism of action and permeation efficiency of the peptides, their encapsulation efficacy, and the antimicrobial activity of these systems. EXPERIMENTS: Encapsulation and delivery of Indolicidin, and its ultra-short derivative, Priscilicidin, were investigated using SAXS, cryo-TEM and circular dichroism. Molecular dynamics simulations were used to understand the loading of these peptides within cubosomes. The antimicrobial efficacy was assessed against gram-negative (E. coli) and gram-positive (MRSA) bacteria. FINDINGS: A high ionic strength solution was required to facilitate high loading of the cationic AMPs, with bilayer encapsulation driven by tryptophan and Fmoc moieties. Cubosome encapsulation did not improve the antimicrobial efficacy of the AMPs consistent with their high permeation, as explained by a recent 'diffusion to capture model'. This suggests that cubosome encapsulation may not be an effective strategy for all antimicrobial compounds, paving the way for improved selection of nanocarriers for AMPs, and other antimicrobial compounds.

CW-PRED: Prediction of C-terminal surface anchoring sorting signals in bacteria and Archaea.

Sorting signals are crucial for the anchoring of proteins to the cell surface in archaea and bacteria. These proteins often feature distinct motifs at their C-terminus, cleaved by sortase or sortase-like enzymes. Gram-positive bacteria exhibit the LPXTGX consensus motif, cleaved by sortases, while Gram-negative bacteria employ exosortases recognizing motifs like PEP. Archaea utilize exosortase homologs known as archaeosortases for signal anchoring. Traditionally identification of such C-terminal sorting signals was performed with profile Hidden Markov Models (pHMMs). The Cell- Wall PREDiction (CW-PRED) method introduced for the first time a custom-made class HMM for proteins in Gram-positive bacteria that contain a cell wall sorting signal which begins with an LPXTG motif, followed by a hydrophobic domain and a tail of positively charged residues. Here we present a new and updated version of CW-PRED for predicting C-terminal sorting signals in Archaea, Gram-positive, and Gram-negative bacteria. We used a large training set and several model enhancements that improve motif identification in order to achieve better discrimination between C-terminal signals and other proteins. Cross-validation demonstrates CW-PRED's superiority in sensitivity and specificity compared to other methods. Application of the method in reference proteomes reveals a large number of potential surface proteins not previously identified. The method is available for academic use at http://195.251.108.230/apps.compgen.org/CW-PRED/ and as standalone software.

Proteomic and metabolomic profiling of methicillin resistant versus methicillin sensitive Staphylococcus aureus using a simultaneous extraction protocol.

Background: Understanding the biology of methicillin resistant Staphylococcus aureus (MRSA) is crucial to unlocking insights for new targets in our fight against this antimicrobial resistant priority pathogen. Although proteomics and metabolomic profiling offer the potential to elucidating such biological markers, reports of methodological approaches for carrying this out in S. aureus isolates remain limited. We describe the use of a dual-functionality methanol extraction method for the concurrent extraction of protein and metabolites from S. aureus and report on the comparative analysis of the proteomic and metabolomic profiles of MRSA versus methicillin sensitive S. aureus (MSSA). Methods: Bacterial reference strains MRSA ATCC43300 and MSSA ATCC25923 were used. The conventional urea methodology was used for protein extraction and a methanol based method was used for concurrent proteins and metabolites extraction. Proteomic and metabolomic profiling was carried out using TimsTOF mass spectrometry. Data processing was carried out using the MaxQuant version 2.1.4.0. Results: This study represents the first report on the utilization of the methanol extraction method for concurrent protein and metabolite extraction in Gram positive bacteria. Our findings demonstrate good performance of the method for the dual extraction of proteins and metabolites from S. aureus with demonstration of reproducibility. Comparison of MRSA and MSSA strains revealed 407 proteins with significantly different expression levels. Enrichment analysis of those proteins revealed distinct pathways involved in fatty acid degradation, metabolism and beta-lactam resistance. Penicillin-binding protein PBP2a, the key determinant of MRSA resistance, exhibited distinct expression patterns in MRSA isolates. Metabolomic analysis identified 146 metabolites with only one exclusive to the MRSA. The enriched pathways identified were related to arginine metabolism and biosynthesis. Conclusion: Our findings demonstrate the effectiveness of the methanol-based dual-extraction method, providing simultaneous insights into the proteomic and metabolomic landscapes of S. aureus strains. These findings demonstrate the utility of proteomic and metabolomic profiling for elucidating the biological basis of antimicrobial resistance.

Repeated Peritonitis in a Peritoneal Dialysis Patient: An Unusual Case of Bacillus licheniformis With Vancomycin Failure Despite Sensitivity.

Bacillus licheniformis (B. licheniformis) is an aerobic, gram-positive, spore-forming rod typically found in soil, decaying organic matter, vegetables, and water, and occasionally part of normal gut flora. This report highlights a case of unusual repeated peritonitis caused by B. licheniformis, with three episodes occurring over six months, all of which were sensitive to vancomycin yet presented an unclear cause for recurrence. Peritonitis represents a significant cause of mortality, hospitalization, and failure of peritoneal dialysis catheters, leading to forced transitions to hemodialysis. The rarity of B. licheniformis as a pathogen in human infections emphasizes the critical need for precise microbial identification and customized therapeutic strategies.

Sarcinaventriculi in association with gastric ulcer: a case report.

Sarcina ventriculi is a species of Gram-positive bacteria which has been reported in patients with delayed gastric emptying as well as in association with cases of gastric ulcer and gastric carcinoma. Although it has been reported frequently in veterinary cases as a cause of fatal diseases, the exact pathogenesis in humans has yet to be identified. We report here a case of an elderly male who presented with haematemesis following which an upper gastrointestinal endoscopy was done and a gastric ulcer was revealed. Histopathological examination revealed S. ventriculi in association with the ulcer.