Antibacterial activity of recently approved antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) strains: A systematic review and meta-analysis

In Silico Identification of Potential Clovibactin-like Antibiotics Binding to Unique Cell Wall Precursors in Diverse Gram-Positive Bacterial Strains

The rise in multidrug-resistant bacteria highlights the critical need for novel antibiotics. This study explores clovibactin-like compounds as potential therapeutic agents targeting lipid II, a crucial component in bacterial cell wall synthesis, using in silico techniques. A total of 2624 clovibactin analogs were sourced from the PubChem database and screened using ProTox 3.0 software based on their ADME-Tox properties, prioritizing candidates with favorable pharmacokinetic profiles and minimal toxicity. Molecular docking protocols were then employed to assess the binding interactions of the selected compounds with lipid II. Our analysis identified Compound 22 as a particularly promising candidate, exhibiting strong binding affinity, stable complex formation, and high selectivity for the target. Binding energy analysis, conducted via molecular dynamics simulations, revealed a highly negative value of -25.50 kcal/mol for Compound 22, surpassing that of clovibactin and underscoring its potential efficacy. In addition, Compound 22 was prioritized due to its exceptional binding affinity to lipid II and its favorable ADME-Tox properties, suggesting a lower likelihood of adverse effects. These characteristics position Compound 22 as a promising candidate for further pharmacological development. While our computational results are encouraging, experimental validation is essential to confirm the efficacy and safety of these compounds. This study not only advances our understanding of clovibactin analogs but also contributes to the ongoing efforts to combat antimicrobial resistance through innovative antibiotic development.

Analysis of antimicrobial resistance and clinical features of Staphylococcus aureus-infected bone and joint infections in children

OBJECTIVE

This study investigates the antimicrobial resistance and clinical features of Staphylococcus aureus (S. aureus) in bone and joint infections (BJIs) among children under 14 years old, providing insights for optimal antibiotic usage.

METHODS

A retrospective analysis was conducted on the clinical data from children treated for BJIs at the Children's Hospital of Soochow University between January 2019 to December 2023. Bacterial cultures were examined, focusing on S. aureus. Clinical features of children with methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) infections were compared.

RESULTS

Among the 110 cases of culture-positive BJIs, 116 pathogenic strains were identified, with, S. aureus being the most prevalent (75.00%, 87/116). No resistance to quinupristin/dalfopristin, linezolid, vancomycin, tigecycline, rifampin or teicoplanin was detected. The resistance rate to penicillin was 90.80% (79/87), while resistance rates to clindamycin and erythromycin were 37.93% (33/87) and 36.78% (32/87), respectively. MRSA accounted for 28.74% (25/87) of S. aureus isolates. There were no significant differences in gender, age, infection site, clinical symptoms, laboratory indicators, hospital stay, or surgical intervention between MSSA and MRSA groups (p > 0.05). However, patients with positive X-ray findings were more likely to have MRSA infections (p = 0.033). Subgroup analysis revealed that children older than 48 months with positive X-ray results were more likely to have MRSA (p = 0.048).

CONCLUSION

In China, S. aureus remains the predominant pathogen in children under 14 years old with BJIs. Among children older than 48 months, nearly one-third of BJIs are caused by MRSA, and positive X-ray findings may indicate a higher likelihood of MRSA in this age group. Further studies are required to validate these findings before they can be widely applied.

CLINICAL TRIAL NUMBER

Not applicable.

Chemical composition, antibacterial and antioxidant activities of Piper betle and Anethum graveolens essential oils against Methicillin-resistant Staphylococcus aureus clinical isolates

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infection worldwide due to its antimicrobial resistance. Plant-derived essential oils (EOs) have undergone extensive observational and clinical research to explore their antimicrobial properties. The present study aimed to check mec A positive MRSA isolates using sequencing analysis, determination of chemical composition using gas chromatography-mass spectroscopy (GC-MS), antioxidant, and antimicrobial activity of Anethum graveolens and Piper betle EOs against the infectious agent MRSA. The result demonstrates a significant antibacterial activity of both essential oils against MRSA clinical isolates. GC-MS analysis of Piper betle showed (41.06%) 3-Allyl-6-methoxyphenol (Eugenol) as the major compound, whereas Anethum graveolens exhibited o-cymene (14.01%) abundantly. Piper betle essential oil retained appreciable levels of total phenolic (39.5 ± 10.9 mg/g of gallic acid equivalents) and flavonoid content (216 ± 145 mg quercetin equivalent/g), when compared to Anethum graveolens essential oil. A strong correlation was observed between antioxidant activity (DPPH, FRAP, and ABTS), total phenolic, and total flavonoid content in the Piper betle and displayed using principal component analysis (PCA) and a scatter matrix plot. Parallelly, clear morphological bacterial alterations were visualized by scanning electron microscopy after treating it with essential oils. MRSA showed malformed cell surfaces or broken cells with pore formation and septae. These findings imply that both essential oils are potential natural sources of antimicrobials against the MRSA superbug. They can also be used in combination therapies with other plant EOs or with traditional antibiotics to combat the rise of bacteria resistance.

Data Mining Models in Prediction of Vancomycin-Intermediate Staphylococcus aureus in Methicillin-Resistant S. aureus (MRSA) Bacteremia Patients in a Clinical Care Setting

Vancomycin-intermediate Staphylococcus aureus (VISA) is a multi-drug-resistant pathogen of significant clinical concern. Various S. aureus strains can cause infections, from skin and soft tissue infections to life-threatening conditions such as bacteremia and pneumonia. VISA infections, particularly bacteremia, are associated with high mortality rates, with 34% of patients succumbing within 30 days. This study aimed to develop predictive models for VISA (including hVISA) bacteremia outcomes using data mining techniques, potentially improving patient management and therapy selection. We focused on three endpoints in patients receiving traditional vancomycin therapy: VISA persistence in bacteremia after 7 days, after 30 days, and patient mortality. Our analysis incorporated 29 risk factors associated with VISA bacteremia. The resulting models demonstrated high predictive accuracy, with 82.0-86.6% accuracy for 7-day VISA persistence in blood cultures and 53.4-69.2% accuracy for 30-day mortality. These findings suggest that data mining techniques can effectively predict VISA bacteremia outcomes in clinical settings. The predictive models developed have the potential to be applied prospectively in hospital settings, aiding in risk stratification and informing treatment decisions. Further validation through prospective studies is warranted to confirm the clinical utility of these predictive tools in managing VISA infections.

Use of lipoglycopeptides for moderate to severe ABSSSI in the emergency department

The burden of acute bacterial skin and skin structure infections (ABSSSI) continue to plague the healthcare system. One approach to managing moderate-to-severe ABSSSI in low-risk patients involves use of a single dose lipoglycopeptide (LGP), dalbavancin or oritavancin, in the emergency department (ED) and discharge to home with follow-up care. Limited ED studies indicate decreased hospital stays, ED revisits, readmissions, and healthcare costs, as well as improved patient satisfaction with use of these antibiotics. However, existing literature has limitations and gaps, such as insufficient quantifiable data on patient selection criteria, outcome predictors, and risk factors leading to treatment failure. Moreover, there is lack of research on the impact of LGPs on organizational productivity, patient quality of life, and utility in indications beyond ABSSSI. This review focuses on the role of long-acting LGPs in the ED setting for select patients presenting with ABSSSI, aiming to avoid hospitalizations, expedite patient discharge, and prevent readmissions while acknowledging potential limitations of therapy. Additionally, it provides insights into strategies and considerations specifically relevant to implementing this therapeutic approach in the ED.

Cannabinoids as Antibacterial Agents: A Systematic and Critical Review of In Vitro Efficacy Against Streptococcus and Staphylococcus

BACKGROUND

Two major bacterial pathogens, Staphylococcus aureus and Streptococcus pyogenes, are becoming increasingly antibiotic-resistant. Despite the urgency, only a few new antibiotics have been approved to address these infections. Although cannabinoids have been noted for their antibacterial properties, a comprehensive review of their effects on these bacteria has been lacking.

OBJECTIVE

This systematic review examines the antibacterial activity of cannabinoids against S. aureus, including methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) strains, and S. pyogenes.

METHODS

Databases, including CINAHL, Cochrane, Medline, Scopus, Web of Science, and LILACS, were searched. Of 3510 records, 24 studies met the inclusion criteria, reporting on the minimum inhibitory concentration (MIC) and minimum bactericidal concentration of cannabinoids.

RESULTS

Cannabidiol (CBD) emerged as the most effective cannabinoid, with MICs ranging from 0.65 to 32 mg/L against S. aureus, 0.5 to 4 mg/L for MRSA, and 1 to 2 mg/L for VRSA. Other cannabinoids, such as cannabichromene, cannabigerol (CBG), and delta-9-tetrahydrocannabinol (Δ9-THC), also exhibited significant antistaphylococcal activity. CBD, CBG, and Δ9-THC also showed efficacy against S. pyogenes, with MICs between 0.6 and 50 mg/L. Synergistic effects were observed when CBD and essential oils from Cannabis sativa when combined with other antibacterial agents.

CONCLUSION

Cannabinoids' antibacterial potency is closely linked to their structure-activity relationships, with features like the monoterpene region, aromatic alkyl side chain, and aromatic carboxylic groups enhancing efficacy, particularly in CBD and its cyclic forms. These results highlight the potential of cannabinoids in developing therapies for resistant strains, though further research is needed to confirm their clinical effectiveness.

Inhibitory effect of Bacillus velezensis 1273 strain cell-free supernatant against developing and preformed biofilms of Staphylococcus aureus and MRSA

Microbial biofilms constitute a significant virulence factor and a substantial challenge in clinical environments due to their role in promoting antimicrobial resistance and their resilience to eradication efforts. Methicillin-resistant Staphylococcus aureus (MRSA) infections substantially increase healthcare costs, extend hospitalizations, and elevate morbidity and mortality rates. Therefore, developing innovative strategies to target and eliminate these bacteria and their biofilms effectively is imperative for robust epidemiological control. In this study, we evaluated the antibacterial and antibiofilm activities of cell-free supernatant (CFS) obtained from the Bacillus velezensis 1273 strain culture. Our data showed that CFS inhibited the growth of S. aureus ATCC 29213 and MRSA (clinical strain), with greater efficacy observed against S. aureus (1:16 dilution). Furthermore, CFS showed substantial potential in reducing biofilm formation in both strains (∼30 %) at subinhibitory concentrations. Additionally, the antibacterial activity against biofilm-formed cells showed that pure CFS treatment decreased the viability of S. aureus (60 %) and MRSA (45 %) sessile cells. We further demonstrated that CFS treatment induces the production of reactive oxygen species (ROS) and damages the membranes and cell walls of the pathogen cells. Genome analysis revealed the presence of genes encoding bacteriocins and secondary metabolites with antibacterial activity in the B. velezensis 1273 genome. These findings highlight the potential of probiotic bacterial metabolites as antibiofilm and anti-multidrug-resistant pathogens.

Antibacterial and antibiofilm potentials of vancomycin-loaded niosomal drug delivery system against methicillin-resistant Staphylococcus aureus (MRSA) infections

The threat of methicillin-resistant Staphylococcus aureus (MRSA) is increasing worldwide, making it significantly necessary to discover a novel way of dealing with related infections. The quick spread of MRSA isolates among infected individuals has heightened public health concerns and significantly limited treatment options. Vancomycin (VAN) can be applied to treat severe MRSA infections, and the indiscriminate administration of this antimicrobial agent has caused several concerns in medical settings. Owing to several advantageous characteristics, a niosomal drug delivery system may increase the potential of loaded antimicrobial agents. This work aims to examine the antibacterial and anti-biofilm properties of VAN-niosome against MRSA clinical isolates with emphasis on cytotoxicity and stability studies. Furthermore, we aim to suggest an effective approach against MRSA infections by investigating the inhibitory effect of formulated niosome on the expression of the biofilm-associated gene (icaR). The thin-film hydration approach was used to prepare the niosome (Tween 60, Span 60, and cholesterol), and field emission scanning electron microscopy (FE-SEM), an in vitro drug release, dynamic light scattering (DLS), and entrapment efficiency (EE%) were used to investigate the physicochemical properties. The physical stability of VAN-niosome, including hydrodynamic size, polydispersity index (PDI), and EE%, was analyzed for a 30-day storage time at 4 °C and 25 °C. In addition, the human foreskin fibroblast (HFF) cell line was used to evaluate the cytotoxic effect of synthesized niosome. Moreover, minimum inhibitory and bactericidal concentrations (MICs/MBCs) were applied to assess the antibacterial properties of niosomal VAN formulation. Also, the antibiofilm potential of VAN-niosome was investigated by microtiter plate (MTP) and real-time PCR methods. The FE-SEM result revealed that synthesized VAN-niosome had a spherical morphology. The hydrodynamic size and PDI of VAN-niosome reported by the DLS method were 201.2 nm and 0.301, respectively. Also, the surface zeta charge of the prepared niosome was - 35.4 mV, and the EE% ranged between 58.9 and 62.5%. Moreover, in vitro release study revealed a sustained-release profile for synthesized niosomal formulation. Our study showed that VAN-niosome had acceptable stability during a 30-day storage time. Additionally, the VAN-niosome had stronger antibacterial and anti-biofilm properties against MRSA clinical isolates compared with free VAN. In conclusion, the result of our study demonstrated that niosomal VAN could be promising as a successful drug delivery system due to sustained drug release, negligible toxicity, and high encapsulation capacity. Also, the antibacterial and anti-biofilm studies showed the high capacity of VAN-niosome against MRSA clinical isolates. Furthermore, the results of real-time PCR exhibited that VAN-niosome could be proposed as a powerful strategy against MRSA biofilm via down-regulation of icaR gene expression.

PharmaRedefine: A database server for repurposing drugs against pathogenic bacteria

Pathogenic bacteria represent a formidable threat to human health, necessitating substantial resources for prevention and treatment. With the escalating concern regarding antibiotic resistance, there is a pressing need for innovative approaches to combat these pathogens. Repurposing existing drugs offers a promising solution. Our present work hypothesizes that proteins harboring ligand-binding pockets with similar chemical environments may be able to bind the same drug. To facilitate this drug-repurposing strategy against pathogenic bacteria, we introduce an online server, PharmaRedefine. Leveraging a combination of sequence and structure alignment and protein pocket similarity analysis, this platform enables the prediction of potential targets in representative bacteria for specific FDA-approved drugs. This novel approach holds tremendous potential for drug repositioning that effectively combat infections caused by pathogenic bacteria. PharmaRedefine is freely available at http://guolab.mpu.edu.mo/pharmredefine.

Oritavancin Versus Daptomycin for Osteomyelitis Treatment After Surgical Debridement

INTRODUCTION

Weekly intravenous (IV) oritavancin and daily daptomycin were compared in an outpatient setting following extensive surgical debridement for treating patients with osteomyelitis.

METHODS

This was a retrospective, observational study of patients diagnosed with acute osteomyelitis. Exclusion criteria were the use of Gram-negative antibiotic therapy, use of antibiotics for more than 48 h prior to oritavancin or daptomycin or prior use of > 2 doses of oritavancin or more than 4 weeks of daptomycin. Clinical success was resolution or improvement of symptoms and no further treatment. Data were analyzed with Chi-square test or Fisher's exact test.

RESULTS

Consecutive outpatients (n = 150) with acute osteomyelitis who were treated with oritavancin or daptomycin (1:1) following extensive surgical debridement were identified. Staphylococcus aureus was the most common pathogen (n = 117). No patient in either group received prior antibiotic therapy (previous 30 days) or was hospitalized within 90 days prior to surgical debridement. Twenty-one (28%) patients prescribed oritavancin had chronic kidney disease, seven of whom were receiving hemodialysis or peritoneal dialysis. Compared to oritavancin, patients prescribed daptomycin had higher rates of all-cause readmission [odds ratio (OR) 2.89; p < 0.001], more infection-related readmission (OR 3.19; p < 0.001), and greater likelihood of receiving antibiotics post-discontinuation of initial therapy (OR 2.13; p < 0.001). Repeat surgical debridement was required for 68.0% with daptomycin vs. 23.1% with oritavancin (p < 0.001).

CONCLUSIONS

Oritavancin demonstrated a significantly higher rate of clinical success compared to daptomycin, with lower all-cause and infection-related readmissions, reduced need for repeat surgical debridement, and fewer additional antibiotic requirements.

Pharmacokinetics and safety of a single dose of telavancin in pediatric subjects 2-17 years of age

Antimicrobial resistance increases infection morbidity in both adults and children, necessitating the development of new therapeutic options. Telavancin, an antibiotic approved in the United States for certain bacterial infections in adults, has not been examined in pediatric patients. The objectives of this study were to evaluate the short-term safety and pharmacokinetics (PK) of a single intravenous infusion of telavancin in pediatric patients. Single-dose safety and PK of 10 mg/kg telavancin was investigated in pediatric subjects >12 months to ≤17 years of age with known or suspected bacterial infection. Plasma was collected up to 24-h post-infusion and analyzed for concentrations of telavancin and its metabolite for noncompartmental PK analysis. Safety was monitored by physical exams, vital signs, laboratory values, and adverse events following telavancin administration. Twenty-two subjects were enrolled: 14 subjects in Cohort 1 (12-17 years), 7 subjects in Cohort 2 (6-11 years), and 1 subject in Cohort 3 (2-5 years). A single dose of telavancin was well-tolerated in all pediatric age cohorts without clinically significant effects. All age groups exhibited increased clearance of telavancin and reduced exposure to telavancin compared to adults, with mean peak plasma concentrations of 58.3 µg/mL (Cohort 1), 60.1 µg/mL (Cohort 2), and 53.1 µg/mL (Cohort 3). A 10 mg/kg dose of telavancin was well tolerated in pediatric subjects. Telavancin exposure was lower in pediatric subjects compared to adult subjects. Further studies are needed to determine the dose required in phase 3 clinical trials in pediatrics.

Multitarget antibacterial drugs: An effective strategy to combat bacterial resistance

The rise of antibiotic resistance and the decrease in the discovery of new antibiotics have caused a global health crisis. Of particular concern is the fact that despite efforts to develop new antibiotics, drug discovery is unable to keep up with the rapid development of resistance. This ongoing crisis highlights the fact that single-target drugs may not always exhibit satisfactory therapeutic effects and are prone to target mutations and resistance due to the complexity of bacterial mechanisms. Retrospective studies have shown that most successful antibiotics have multiple targets. Compared with single-target drugs, successfully designed multitarget drugs can simultaneously regulate multiple targets to reduce resistance caused by single-target mutations or expression changes. In addition to a lower risk of drug-drug interactions, multitarget drugs show superior pharmacokinetics and higher patient compliance compared with combination therapies. Therefore, to reduce resistance, many efforts have been made to discover and design multitarget drugs with different chemical structures and functions. Although there have been numerous studies on how to develop drugs and slow down the development of drug resistance, the reduction of bacterial resistance by multitarget antibacterial drugs has not received widespread attention and is rarely mentioned in the peer-reviewed literature. This review summarises the development of antibiotic resistance and the mechanisms proposed for its emergence, examines the potential of multitarget drugs as an effective strategy to slow the development of resistance, and discusses the rationale for multitarget drug therapy. We also describe multitarget antibacterial compounds with the potential to reduce drug resistance and the available strategies to develop multitarget drugs.

Modulation of the Gut Microbiota by the Plantaricin-Producing Lactiplantibacillus plantarum D13, Analysed in the DSS-Induced Colitis Mouse Model

Lactiplantibacillus plantarum D13 shows antistaphylococcal and antilisterial activity, probably due to the synthesis of a presumptive bacteriocin with antibiofilm capacity released in the cell-free supernatant (CFS), whose inhibitory effect is enhanced by cocultivation with susceptible strains. An in silico analysis of the genome of strain D13 confirmed the pln gene cluster. Genes associated with plantaricin biosynthesis, structure, transport, antimicrobial activity, and immunity of strain D13 were identified. Furthermore, the predicted homology-based 3D structures of the cyclic conformation of PlnE, PlnF, PlnJ, and PlnK revealed that PlnE and PlnK contain two helices, while PlnF and PlnJ contain one and two helices, respectively. The potential of the strain to modulate the intestinal microbiota in healthy or dextran sulphate sodium (DSS)-induced colitis mouse models was also investigated. Strain D13 decreased the disease activity index (DAI) and altered the gut microbiota of mice with DSS-induced colitis by increasing the ratio of beneficial microbial species (Allobaculum, Barnesiella) and decreasing those associated with inflammatory bowel disease (Candidatus Saccharimonas). This suggests that strain D13 helps to restore the gut microbiota after DSS-induced colitis, indicating its potential for further investigation as a probiotic strain for the prevention and treatment of colitis.

Anti-methicillin-resistant Staphylococcus aureus and antibiofilm activity of new peptides produced by a Brevibacillus strain

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is listed as a highly prioritized pathogen by the World Health Organization (WHO) to search for effective antimicrobial agents. Previously, we isolated a soil Brevibacillus sp. strain SPR19 from a botanical garden, which showed anti-MRSA activity. However, the active substances were still unknown.

Methods

The cell-free supernatant of this bacterium was subjected to salt precipitation, cation exchange, and reversed-phase chromatography. The antimicrobial activity of pure substances was determined by broth microdilution assay. The peptide sequences and secondary structures were characterized by tandem mass spectroscopy and circular dichroism (CD), respectively. The most active anti-MRSA peptide underwent a stability study, and its mechanism was determined through scanning electron microscopy, cell permeability assay, time-killing kinetics, and biofilm inhibition and eradication. Hemolysis was used to evaluate the peptide toxicity.

Results

The pure substances (BrSPR19-P1 to BrSPR19-P5) were identified as new peptides. Their minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) against S. aureus and MRSA isolates ranged from 2.00 to 32.00 and 2.00 to 64.00 µg/mL, respectively. The sequence analysis of anti-MRSA peptides revealed a length ranging from 12 to 16 residues accompanied by an amphipathic structure. The physicochemical properties of peptides were predicted such as pI (4.25 to 10.18), net charge at pH 7.4 (-3 to +4), and hydrophobicity (0.12 to 0.96). The CD spectra revealed that all peptides in the water mainly contained random coil structures. The increased proportion of α-helix structure was observed in P2-P5 when incubated with SDS. P2 (NH2-MFLVVKVLKYVV-COOH) showed the highest antimicrobial activity and high stability under stressed conditions such as temperatures up to 100 °C, solution of pH 3 to 10, and proteolytic enzymes. P2 disrupted the cell membrane and caused bacteriolysis, in which its action was dependent on the incubation time and peptide concentration. Antibiofilm activity of P2 was determined by which the half-maximal inhibition of biofilm formation was observed at 2.92 and 4.84 µg/mL for S. aureus TISTR 517 and MRSA isolate 2468, respectively. Biofilm eradication of tested pathogens was found at the P2 concentration of 128 µg/mL. Furthermore, P2 hemolytic activity was less than 10% at concentrations up to 64 µg/mL, which reflected the hemolysis index thresholds of 32.

Conclusion

Five novel anti-MRSA peptides were identified from SPR19. P2 was the most active peptide and was demonstrated to cause membrane disruption and cell lysis. The P2 activity was dependent on the peptide concentration and exposure time. This peptide had antibiofilm activity against tested pathogens and was compatible with human erythrocytes, supporting its potential use as an anti-MRSA agent in this post-antibiotic era.

The Clinical Efficacy of Multidose Oritavancin: A Systematic Review

Oritavancin (ORI) is a semisynthetic lipoglycopeptide approved as a single 1200 mg dose intravenous infusion for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) caused by Gram-positive organisms in adults. The pharmacokinetic/pharmacodynamic (PK/PD) linear kinetic profile and long terminal half-life (~393 h) of ORI make it therapeutically attractive for the treatment of other Gram-positive infections for which prolonged therapy is needed. Multidose regimens are adopted in real-world clinical practice with promising results, but aggregated efficacy data are still lacking. A comprehensive search on PubMed/Medline, Scopus, Cochrane and Google Scholar databases was performed to include papers published up to the end of January 2023. All articles on ORI multiple doses usage, including case reports, with quantitative data and relevant clinical information were included. Two reviewers independently assessed papers against the inclusion/exclusion criteria and for methodological quality. Differences in opinion were adjudicated by a third party. From 1751 potentially relevant papers identified by this search, a total of 16 studies met the inclusion criteria and were processed further in the final data analysis. We extracted data concerning clinical response, bacteriologic response, mortality and adverse events (AEs). From the 16 included papers, 301 cases of treatment with multidose ORIs were identified. Multidose regimens comprised an initial ORI dose of 1200 mg followed by 1200 mg or 800 mg subsequent doses with a varying total number and frequency of reinfusions. The most often treated infections and isolates were osteomyelitis (148; 54.4%), ABSSSI (35; 12.9%) and cellulitis (14; 5.1%); and MRSA (121), MSSA (66), CoNS (17), E. faecalis (13) and E. faecium (12), respectively. Clinical cure and improvement by multidose ORI regimens were observed in 85% (231/272) and 8% (22/272) patients, respectively. Multidose ORI was safe and well tolerated; the most frequent AEs were infusion-related reactions and hypoglycemia. A multidose ORI regimen may be beneficial in treating other Gram-positive infections besides ABSSSIs, with a good safety profile. Further studies are warranted to ascertain the superiority of one multidose ORI scheme or posology over the other.

In Vitro Activities of Ceftobiprole, Dalbavancin, Tedizolid and Comparators against Clinical Isolates of Methicillin-Resistant Staphylococcus aureus Associated with Skin and Soft Tissue Infections

Skin and soft tissue infections (SSTIs) are associated with significant morbidity and healthcare costs, especially when caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is a preferred antimicrobial therapy for the management of complicated SSTIs (cSSTIs) caused by MRSA, with linezolid and daptomycin regarded as alternative therapeutic options. Due to the increased rates of antimicrobial resistance in MRSA, several new antibiotics with activity against MRSA have been recently introduced in clinical practice, including ceftobiprole, dalbavancin, and tedizolid. We evaluated the in vitro activities of the aforementioned antibiotics against 124 clinical isolates of MRSA obtained from consecutive patients with SSTIs during the study period (2020-2022). Minimum inhibitory concentrations (MICs) for vancomycin, daptomycin, ceftobiprole, dalbavancin, linezolid and tedizolid were evaluated by the MIC Test Strip using Liofilchem strips. We found that when compared to the in vitro activity of vancomycin (MIC₉₀ = 2 μg/mL), dalbavancin possessed the lowest MIC₉₀ (MIC₉₀ = 0.094 μg/mL), followed by tedizolid (MIC₉₀ = 0.38 μg/mL), linezolid, ceftobiprole, and daptomycin (MIC₉₀ = 1 μg/mL). Dalbavancin demonstrated significantly lower MIC₅₀ and MIC₉₀ values compared to vancomycin (0.064 vs. 1 and 0.094 vs. 2, respectively). Tedizolid exhibited an almost threefold greater level of in vitro activity than linezolid, and also had superior in vitro activity compared to ceftobiprole, daptomycin and vancomycin. Multidrug-resistant (MDR) phenotypes were detected among 71.8% of the isolates. In conclusion, ceftobiprole, dalbavancin and tedizolid exhibited potent activity against MRSA and are promising antimicrobials in the management of SSTIs caused by MRSA.

Staphylococcus aureus Infection: Pathogenesis and Antimicrobial Resistance

Staphylococcus aureus, a Gram-positive, coagulase-positive pathogen belonging to the family Staphylococcaceae with a spherical shape that forms grape-like clusters, is a commensal that is often present asymptomatically on parts of the human body [...].

Phytochemical-Based Nanomaterials against Antibiotic-Resistant Bacteria: An Updated Review

Antibiotic-resistant bacteria (ARB) is a growing global health threat, leading to the search for alternative strategies to combat bacterial infections. Phytochemicals, which are naturally occurring compounds found in plants, have shown potential as antimicrobial agents; however, therapy with these agents has certain limitations. The use of nanotechnology combined with antibacterial phytochemicals could help achieve greater antibacterial capacity against ARB by providing improved mechanical, physicochemical, biopharmaceutical, bioavailability, morphological or release properties. This review aims to provide an updated overview of the current state of research on the use of phytochemical-based nanomaterials for the treatment against ARB, with a special focus on polymeric nanofibers and nanoparticles. The review discusses the various types of phytochemicals that have been incorporated into different nanomaterials, the methods used to synthesize these materials, and the results of studies evaluating their antimicrobial activity. The challenges and limitations of using phytochemical-based nanomaterials, as well as future directions for research in this field, are also considered here. Overall, this review highlights the potential of phytochemical-based nanomaterials as a promising strategy for the treatment against ARB, but also stresses the need for further studies to fully understand their mechanisms of action and optimize their use in clinical settings.

Diclofenac and Meloxicam Exhibited Anti-Virulence Activities Targeting Staphyloxanthin Production in Methicillin-Resistant Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a worldwide leading versatile pathogen that causes a wide range of serious infections. The emergence of antimicrobial resistance against S. aureus resulted in an urgent need to develop new antimicrobials in the new era. The methicillin-resistant S. aureus (MRSA) prevalence in hospital and community settings necessitates the discovery of novel anti-pathogenic agents. Staphyloxanthin (STX) is a key virulence factor for the survival of MRSA against host innate immunity. The current work aimed to demonstrate the anti-virulence properties of meloxicam (MXM) as compared to diclofenac (DC), which was previously reported to mitigate the virulence of multidrug-resistant Staphylococcus aureus and test their activities in STX production. A total of 80 S. aureus clinical isolates were included, wherein a qualitative and quantitative assessment of STX inhibition by diclofenac and meloxicam was performed. The quantitative gene expression of STX biosynthetic genes (crtM, crtN and sigB) and hla (coded for α-hemolysin) as a virulence gene with and without DC and MXM was conducted, followed by molecular docking analysis for further confirmation. DC and MXM potently inhibited the synthesis of STX at 47 and 59 µg/mL to reach 79.3-98% and 80.6-96.7% inhibition, respectively. Treated cells also revealed a significant downregulation of virulence genes responsible for STX synthesis, such as crtM, crtN and global transcriptional regulator sigB along with the hla gene. Furthermore, computational studies unveiled strong interactions between the CrtM binding site and DC/MXM. In conclusion, this study highlights the potential role and repurposing of DC and MXM as adjuvants to conventional antimicrobials and as an anti-virulent to combat MRSA infections.

Current molecular approach for diagnosis of MRSA: a meta-narrative review

Introduction:

Detection and diagnosis of methicillin-resistant Staphylococcus aureus (MRSA) are important in ensuring a correct and effective treatment, further reducing its spread. A wide range of molecular approaches has been used for the diagnosis of antimicrobial resistance (AMR) in MRSA. This review aims to study and appraise widely used molecular diagnostic methods for detecting MRSA.

Methods:

This meta-narrative review was performed by searching PubMed using the following search terms: (molecular diagnosis) AND (antimicrobial resistance) AND (methicillin-resistant Staphylococcus aureus). Studies using molecular diagnostic techniques for the detection of MRSA were included, while non-English language, duplicates and non-article studies were excluded. After reviewing the libraries and a further manual search, 20 studies were included in this article. RAMESES publication standard for narrative reviews was used for this synthesis.

Results:

A total of 20 full papers were reviewed and appraised in this synthesis, consisting of PCR technique (n = 7), deoxyribonucleic acid (DNA) Microarray (n = 1), DNA sequencing (n = 2), Xpert MRSA/SA BC assay (n = 2), matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) (n = 2), MLST (n = 4), SCCmec typing (n = 1) and GENECUBE (n = 1).

Discussion:

Different diagnostic methods used to diagnose MRSA have been studied in this review. This study concludes that PCR has been extensively used due to its higher sensitivity and cost-effectiveness in the past five years