Clostridium Perfringens as a Rare Cause of Spontaneous Bacterial Peritonitis.

Spontaneous bacterial peritonitis (SBP) is a serious complication in individuals with liver cirrhosis and ascites. In this case report, we present an unusual cause of SBP in loculated ascites caused by an uncommon bacterium, Clostridium perfringens. Although SBP is typically associated with certain common pathogens, it is important to recognize that less frequent organisms can also trigger it. C. perfringens is typically associated with other environmental sources, but in this instance, the infection's origin was suspected to be either nosocomial, from prior paracentesis, or due to a microscopic bowel perforation that was undetectable on imaging. Remarkably, the patient responded well with an improvement of symptoms, and the ascitic fluid bacterial growth resolved on subsequent cultures.

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.

Ticagrelor alters the membrane of Staphylococcus aureus and enhances the activity of vancomycin and daptomycin without eliciting cross-resistance.

Infections with multidrug-resistant bacteria pose a major healthcare problem which urges the need for novel treatment options. Besides its potent antiplatelet properties, ticagrelor has antibacterial activity against Gram-positive bacteria, including methicillin- and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA). Several retrospective studies in cardiovascular patients support an antibacterial effect of this drug which is not related to its antiplatelet activity. We investigated the mechanism of action of ticagrelor in Staphylococcus aureus and model Bacillus subtilis, and assessed cross-resistance with two conventional anti-MRSA antibiotics, vancomycin and daptomycin. Bacillus subtilis bioreporter strains revealed ticagrelor-induced cell envelope-related stress responses. Sub-inhibitory drug concentrations caused membrane depolarization, impaired positioning of both the peripheral membrane protein MinD and the peptidoglycan precursor lipid II, and it affected cell shape. At the MIC, ticagrelor destroyed membrane integrity, indicated by the influx of membrane impermeable dyes, and lipid aggregate formation. Whole-genome sequencing of in vitro-generated ticagrelor-resistant MRSA clones revealed mutations in genes encoding ClpP, ClpX, and YjbH. Lipidomic analysis of resistant clones displayed changes in levels of the most abundant lipids of the Staphylococcus aureus membrane, for example, cardiolipins, phosphatidylglycerols, and diacylglycerols. Exogeneous cardiolipin, phosphatidylglycerol, or diacylglycerol antagonized the antibacterial properties of ticagrelor. Ticagrelor enhanced MRSA growth inhibition and killing by vancomycin and daptomycin in both exponential and stationary phases. Finally, no cross-resistance was observed between ticagrelor and daptomycin, or vancomycin. Our study demonstrates that ticagrelor targets multiple lipids in the cytoplasmic membrane of Gram-positive bacteria, thereby retaining activity against multidrug-resistant staphylococci including daptomycin- and vancomycin-resistant strains.IMPORTANCEInfections with multidrug-resistant bacteria pose a major healthcare problem with an urgent need for novel treatment options. The antiplatelet drug ticagrelor possesses antibacterial activity against Gram-positive bacteria including methicillin-resistant and vancomycin-resistant Staphylococcus aureus strains. We report a unique, dose-dependent, antibacterial mechanism of action of ticagrelor, which alters the properties and integrity of the bacterial cytoplasmic membrane. Ticagrelor retains activity against multidrug-resistant staphylococci, including isolates carrying the most common in vivo selected daptomycin resistance mutations and vancomycin-intermediate Staphylococcus aureus. Our data support the use of ticagrelor as adjunct therapy against multidrug-resistant strains. Because of the presence of multiple non-protein targets of this drug within the bacterial membrane, resistance development is expected to be slow. All these findings corroborate the accumulating observational clinical evidence for a beneficial anti-bacterial effect of ticagrelor in cardiovascular patients in need of such treatment.

Agents Targeting the Bacterial Cell Wall as Tools to Combat Gram-Positive Pathogens.

The cell wall is an indispensable element of bacterial cells and a long-known target of many antibiotics. Penicillin, the first discovered beta-lactam antibiotic inhibiting the synthesis of cell walls, was successfully used to cure many bacterial infections. Unfortunately, pathogens eventually developed resistance to it. This started an arms race, and while novel beta-lactams, either natural or (semi)synthetic, were discovered, soon upon their application, bacteria were developing resistance. Currently, we are facing the threat of losing the race since more and more multidrug-resistant (MDR) pathogens are emerging. Therefore, there is an urgent need for developing novel approaches to combat MDR bacteria. The cell wall is a reasonable candidate for a target as it differentiates not only bacterial and human cells but also has a specific composition unique to various groups of bacteria. This ensures the safety and specificity of novel antibacterial agents that target this structure. Due to the shortage of low-molecular-weight candidates for novel antibiotics, attention was focused on peptides and proteins that possess antibacterial activity. Here, we describe proteinaceous agents of various origins that target bacterial cell wall, including bacteriocins and phage and bacterial lysins, as alternatives to classic antibiotic candidates for antimicrobial drugs. Moreover, advancements in protein chemistry and engineering currently allow for the production of stable, specific, and effective drugs. Finally, we introduce the concept of selective targeting of dangerous pathogens, exemplified by staphylococci, by agents specifically disrupting their cell walls.

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.

European Society of Clinical Microbiology and Infectious Diseases/European Committee on infection control clinical guidelines on pre-operative 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 for 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/European Committee on Infection Control guidelines were developed following a systematic review of published studies targeting methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci, methicillin-resistant coagulase-negative Staphylococci, and pan-drug-resistant-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 the incidence of Clostridioides difficile infections. The last search of all databases was performed on 1 November 2023. The level of evidence and the strength of each recommendation were defined according to the Grading of Recommendations Assessment, Development, and Evaluation 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 before high-risk operations, such as cardiothoracic and orthopaedic surgery. Decolonization with intranasal mupirocin with or without a chlorhexidine bath is recommended in patients colonized with S. aureus before cardiothoracic and orthopaedic surgery and suggested in other surgeries. The addition of vancomycin to standard prophylaxis is suggested for MRSA carriers in cardiothoracic surgery, orthopaedic surgery, and neurosurgery. Combined interventions (e.g. decolonization and targeted prophylaxis) are suggested for MRSA carriers undergoing cardiothoracic and orthopaedic surgery. No recommendation could be made regarding screening, decolonization and targeted prophylaxis for vancomycin-resistant enterococci because of the lack of data. No evidence was retrieved for methicillin-resistant coagulase-negative Staphylococci and pan-drug-resistant-GPB. Careful consideration of the laboratory workload and involvement of antimicrobial stewardship and 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.

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.

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.

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.

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.

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.

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.

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.

Native Infective Endocarditis: A State-of-the-Art-Review.

Native valve infective endocarditis (NVE) is a global phenomenon, defined by infection of a native heart valve and involving the endocardial surface. The causes and epidemiology of the disease have evolved in recent decades, with a doubling of the average patient age. A higher incidence was observed in patients with implanted cardiac devices that can result in right-sided infection of the tricuspid valve. The microbiology of the disease has also changed. Previously, staphylococci, which are most often associated with health-care contact and invasive procedures, were the most common cause of the disease. This has now been superseded by streptococci. While innovative diagnostic and therapeutic strategies have emerged, mortality rates have not improved and remain at 30%, which is higher than that for many cancer diagnoses. The lack of randomized trials and logistical constraints impede clinical management, and long-standing controversies such as the use of antibiotic prophylaxis persist. This state of the art review addresses clinical practice, controversies, and strategies to combat this potentially devastating disease. A multidisciplinary team will be established to provide care for patients with presumptive NVE. The composition of the team will include specialists in cardiology, cardiovascular surgery, and infectious disease. The prompt administration of combination antimicrobial therapy is essential for effective NVE treatment. Additionally, a meticulous evaluation of each patient is necessary in order to identify any indications for immediate valve surgery. With the intention of promoting a more comprehensive understanding of the procedural management of native infective endocarditis and to furnish clinicians with a reference, the current evidence for the utilization of distinct strategies for the diagnosis and treatment of NVE are presented.

Poly Lactic-co-Glycolic Acid (PLGA) Loaded with a Squaraine Dye as Photosensitizer for Antimicrobial Photodynamic Therapy.

Antimicrobial Photodynamic Therapy (aPDT) is an innovative and promising method for combating infections, reducing the risk of antimicrobial resistance compared to traditional antibiotics. Squaraine (SQ) dyes can be considered promising photosensitizers (PSs) but are generally hydrophobic molecules that can self-aggregate under physiological conditions. To overcome these drawbacks, a possible solution is to incorporate SQs inside nanoparticles (NPs). The present work deals with the design and development of innovative nanophotosensitizers based on poly lactic-co-glycolic acid (PLGA) NPs incorporating a brominated squaraine (BrSQ) with potential application in aPDT. Two designs of experiments (DoEs) based on the single emulsion and nanoprecipitation methods were set up to investigate how different variables (type of solvent, solvent ratio, concentration of PLGA, stabilizer and dye, sonication power and time) can affect the size, zeta (ζ)-potential, yield, entrapment efficiency, and drug loading capacity of the SQ-PLGA NPs. SQ-PLGA NPs were characterized by NTA, FE-SEM, and UV-Vis spectroscopy and the ability to produce reactive oxygen species (ROS) was evaluated, proving that ROS generation ability is preserved in SQ-PLGA. In vitro antimicrobial activity against Gram-positive bacteria in planktonic state using Staphylococcus aureus was conducted in different conditions and pH to evaluate the potential of these nanophotosensitizers for aPDT in the local treatment of infections.

Capabilities of GPT-4o and Gemini 1.5 Pro in Gram stain and bacterial shape identification.

Aim: Assessing the visual accuracy of two large language models (LLMs) in microbial classification. Materials & methods: GPT-4o and Gemini 1.5 Pro were evaluated in distinguishing Gram-positive from Gram-negative bacteria and classifying them as cocci or bacilli using 80 Gram stain images from a labeled database. Results: GPT-4o achieved 100% accuracy in identifying simultaneously Gram stain and shape for Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro showed more variability for similar bacteria (45, 100 and 95%, respectively). Both LLMs failed to identify both Gram stain and bacterial shape for Neisseria gonorrhoeae. Cumulative accuracy plots indicated that GPT-4o consistently performed equally or better in every identification, except for Neisseria gonorrhoeae's shape. Conclusion: These results suggest that these LLMs in their unprimed state are not ready to be implemented in clinical practice and highlight the need for more research with larger datasets to improve LLMs' effectiveness in clinical microbiology.

This study looked at how well large language models (LLMs) could identify different types of bacteria using images, without having any specific training in this area beforehand.We tested two LLMs with image analysis capabilities, GPT-4o and Gemini 1.5 Pro. These models were asked to determine whether bacteria were Gram-positive or Gram-negative and whether they were round (cocci) or rod-shaped (bacilli). We used 80 images of four stained bacteria from a labeled database as a reference for this test.GPT-4o was more accurate in identifying both the Gram stain and shape of the bacteria compared with Gemini 1.5 Pro. GPT-4o had excellent accuracy in correctly classifying the Gram stain and bacterial shape of Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro had mixed results for these bacteria. However, both models struggled with Neisseria gonorrhoeae, failing to correctly identify its Gram stain and shape.The study shows that while these LLMs have potential, they are not ready to be implemented in clinical practice. More research and larger datasets are needed to improve their accuracy in clinical microbiology.

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.