Is there still a role for vancomycin in skin and soft-tissue infections?

A magnetic-guided nano-antibacterial platform for alternating magnetic field controlled vancomycin release in staphylococcus aureus biofilm eradication

Bacterial resilience within biofilms, rendering them up to 1000 times more resistant to antibiotic drugs, poses a formidable challenge. This study introduces a targeted biofilm eradication strategy, termed "target-penetration-killing-eradication", implemented through magnetic micro-robotic technology. Specifically, we present the development of a magnetic-guided nano-antibacterial platform designed for alternating magnetic field (AMF) controlled vancomycin release in the eradication of Staphylococcus aureus biofilms. To address the issue of premature vancomycin release in physiological conditions, we employed a temperature-sensitive linking agent, 4,4'-azobis(4-cyano valeric acid), facilitating the conjugation of vancomycin onto Fe3O4/CS nanocomposites, resulting in the novel construct Fe3O4@CS-ACVA-VH. The release mechanism adheres to first-order kinetics and Fickian diffusion, with each 10-min AMF treatment releasing approximately 8.4 ± 1.1% of vancomycin. The potency of vancomycin in the release solution was similar to that of the original drug (MIC: 7.4 ± 3.5 vs. 5.6 μg/mL). Fe3O4@CS-ACVA-VH exhibited sustained antibacterial efficacy, inhibiting bacterial growth for four consecutive days and preventing the formation of bacterial biofilms on its surface. Contact-inhibition bacterial activity of Fe3O4@CS-ACVA-VH against S. aureus was 0.046875 mg/mL. Conceptually validating our approach, we emphasize Fe3O4@CS-ACVA-VH's exceptional ability to penetrate S. aureus biofilms under static magnetic field attraction. Furthermore, the nano-platform offers the unique advantage of on-demand vancomycin release through alternating magnetic field stimulation, effectively clearing a larger biofilm area. This multifunctional nano-platform demonstrates magnetic-guided biofilm penetration followed by controlled vancomycin release, presenting a promising strategy for enhanced biofilm eradication.

Synergistic Antimicrobial Activity of Magnetite and Vancomycin-Loaded Mesoporous Silica Embedded in Alginate Films

The aim of the present study was to obtain a hydrogel-based film as a carrier for the sustained and controlled release of vancomycin, an antibiotic commonly used in various types of infections. Considering the high-water solubility of vancomycin (>50 mg/mL) and the aqueous medium underlying the exudates, a prolonged release of vancomycin from an MCM-41 carrier was sought. The present work focused on the synthesis of malic acid coated magnetite (Fe3O4/malic) by co-precipitation, synthesis of MCM-41 by a sol-gel method and loading of MCM-41 with vancomycin, and their use in alginate films for wound dressing. The nanoparticles obtained were physically mixed and embedded in the alginate gel. Prior to incorporation, the nanoparticles were characterized by XRD, FT-IR and FT-Raman spectroscopy, TGA-DSC and DLS. The films were prepared by a simple casting method and were further cross-linked and examined for possible heterogeneities by means of FT-IR microscopy and SEM. The degree of swelling and the water vapor transmission rate were determined, considering their potential use as wound dressings. The obtained films show morpho-structural homogeneity, sustained release over 48 h and a strong synergistic enhancement of the antimicrobial activity as a consequence of the hybrid nature of these films. The antimicrobial efficacy was tested against S. aureus, two strains of E. faecalis (including vancomycin-resistant Enterococcus, VRE) and C. albicans. The incorporation of magnetite was also considered as an external triggering component in case the films were used as a magneto-responsive smart dressing to stimulate vancomycin diffusion.

Hybrid microneedle arrays for antibiotic and near-IR photothermal synergistic antimicrobial effect against Methicillin-Resistant Staphylococcus aureus

The rise of antibiotic-resistant skin and soft tissue infections (SSTIs) necessitates the development of novel treatments to improve the efficiency and delivery of antibiotics. The incorporation of photothermal agents such as plasmonic nanoparticles (NPs) improves the antibacterial efficiency of antibiotics through synergism with elevated temperatures. Hybrid microneedle (MN) arrays are promising local delivery platforms that enable co-therapy with therapeutic and photothermal agents. However, to-date, the majority of hybrid MNs have focused on the potential treatment of skin cancers, while suffering from the shortcoming of the intradermal release of photothermal agents. Here, we developed hybrid, two-layered MN arrays consisting of an outer water-soluble layer loaded with vancomycin (VAN) and an inner water-insoluble near-IR photothermal core. The photothermal core consists of flame-made plasmonic Au/SiO2 nanoaggregates and polymethylmethacrylate (PMMA). We analyzed the effect of the outer layer polymer, polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), on MN morphology and performance. Hybrid MNs produced with 30 wt% PVA contain a highly drug-loaded outer shell allowing for the incorporation of VAN concentrations up to 100 mg g-1 and temperature increases up to 60 °C under near-IR irradiation while showing sufficient mechanical strength for skin insertion. Furthermore, we studied the combinatorial effect of VAN and heat on the growth inhibition of methicillin-resistant Staphylococcus aureus (MRSA) showing synergistic inhibition between VAN and heat above 55 °C for 10 min. Finally, we show that treatment with hybrid MN arrays can inhibit the growth of MRSA due to the synergistic interaction of heat with VAN reducing the bacterial survival by up to 80%. This proof-of-concept study demonstrates the potential of hybrid, two-layered MN arrays as a novel treatment option for MRSA-associated skin infections.

Escalation of antimicrobial resistance among MRSA part 2: focus on infections and treatment

INTRODUCTION

MRSA is associated with causing a variety of infections including skin and skin structure infections, catheter and device-related (e.g. central venous catheter, prosthetic heart valve) infections, infectious endocarditis, blood stream infections, bone, and joint infections (e.g. osteomyelitis, prosthetic joint, surgical site), central nervous system infections (e.g. meningitis, brain/spinal cord abscess, ventriculitis, hydrocephalus), respiratory tract infections (e.g. hospital-acquired pneumonia, ventilator-associated pneumonia), urinary tract infections, and gastrointestinal infections. The emergence and spread of multidrug resistant (MDR) MRSA clones has limited therapeutic options. Older agents such as vancomycin, linezolid and daptomycin and a variety of newer MRSA antimicrobials and combination therapy are available to treat serious MRSA infections.

AREAS COVERED

The authors discuss infections caused by MRSA as well as common older and newer antimicrobials and combination therapy for MRSA infections. A literature search of MRSA was performed via PubMed (up to September 2022), using the keywords: antimicrobial resistance; β-lactams; multidrug resistance, Staphylococcus aureus, vancomycin; glycolipopeptides.

EXPERT OPINION

Innovation, discovery, and development of new and novel classes of antimicrobial agents are critical to expand effective therapeutic options. The authors encourage the judicious use of antimicrobials in accordance with antimicrobial stewardship programs along with infection-control measures to minimize the spread of MRSA.

Antimicrobial Management of Skin and Soft Tissue Infections among Surgical Wards in South Africa: Findings and Implications

Skin and soft tissue infections (SSTIs) are one of the most common infectious diseases requiring antibiotics. However, complications of SSTIs may lead to the overprescribing of antibiotics and to subsequent antibiotic resistance. Consequently, monitoring the prescribing alignment with the current recommendations from the South African Standard Treatment Guidelines (STG) is necessary in order to improve future care. This study involved reviewing pertinent patients with SSTIs who were prescribed antimicrobials in the surgical ward of a leading South African tertiary public hospital from April to June 2021 using an adapted data collection tool. Sixty-seven patient files were reviewed. Among the patients with SSTIs, hypertension and chronic osteomyelitis were the most frequent co-morbidities at 22.4% and 13.4%, respectively. The most diagnosed SSTIs were surgical site infections (35.1%), wound site infections (23%), and major abscesses (16.2%). Blood cultures were performed on 40.3% of patients, with Staphylococcus aureus (32.7%) and Enterococcus spp. (21.2%) being the most cultured pathogens. Cefazolin was prescribed empirically for 46.3% of patients for their SSTIs. In addition, SSTIs were treated with gentamycin, ciprofloxacin, and rifampicin at 17.5%, 11.3%, and 8.8%, respectively, with treatment fully complying with STG recommendations in 55.2% of cases. Overall, the most common cause of SSTIs was Staphylococcus aureus, and empiric treatment is recommended as the initial management. Subsequently, culture sensitivities should be performed to enhance adherence to STGs and to improve future care.

Mas-Related G Protein–Coupled Receptor-X2 and Its Role in Non-immunoglobulin E–Mediated Drug Hypersensitivity

A diverse group of Food and Drug Administration-approved cationic drugs including antibiotics, neuromuscular blocking drugs, opioids, antidepressants, and radiocontrast media activate mast cells and cause hypersensitivity reactions by both an immunoglobulin E IgE-dependent and independent manner. The recent discovery that these drugs activate mast cells via the G protein-coupled receptor known as Mas-related GPCR-X2 (MRGPRX2) has represented a paradigm shift of how drug hypersensitivity reactions are viewed. This article provides an overview of the current status of the role of MRGPRX2 on non-IgE-mediated drug hypersensitivity. Potential risk factors and evaluation for suspected MRGPRX2-mediated drug reactions are also discussed.

Study on Demethoxycurcumin as a Promising Approach to Reverse Methicillin-Resistance of Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) has always been a threatening pathogen. Research on phytochemical components that can replace antibiotics with limited efficacy may be an innovative method to solve intractable MRSA infections. The present study was devoted to investigate the antibacterial activity of the natural compound demethoxycurcumin (DMC) against MRSA and explore its possible mechanism for eliminating MRSA. The minimum inhibitory concentrations (MICs) of DMC against MRSA strains was determined by the broth microdilution method, and the results showed that the MIC of DMC was 62.5 μg/mL. The synergistic effects of DMC and antibiotics were investigated by the checkerboard method and the time–kill assay. The ATP synthase inhibitors were employed to block the metabolic ability of bacteria to explore their synergistic effect on the antibacterial ability of DMC. In addition, western blot analysis and qRT-PCR were performed to detect the proteins and genes related to drug resistance and S. aureus exotoxins. As results, DMC hindered the translation of penicillin-binding protein 2a (PBP2a) and staphylococcal enterotoxin and reduced the transcription of related genes. This study provides experimental evidences that DMC has the potential to be a candidate substance for the treatment of MRSA infections.

New Evidence and Insights on Dalbavancin and Wound Healing in a Mouse Model of Skin Infection

Dalbavancin is an effective antibiotic that is widely used to treat skin infection. Our aim was to determine the effect of dalbavancin administration on wound healing compared to that of vancomycin and to elucidate if epidermal growth factor receptor (EGFR), matrix metalloproteinase 1 (MMP-1), MMP-9, and vascular endothelial growth factor (VEGF) could be involved in its therapeutic mechanism. A mouse model of methicillin-resistant Staphylococcus aureus (MRSA) skin infection was established. Mice were treated daily with vancomycin (10 mg/kg) and weekly with dalbavancin at day 1 (20 mg/kg) and day 8 (10 mg/kg). After 14 days, wounds were excised, and bacterial counts were performed. Wound healing was assessed by histological and immunohistochemical staining, followed by protein extraction and immunoblotting. Our microbiological results confirmed that both dalbavancin and vancomycin are effective in reducing the bacterial load in wounds. The dalbavancin group showed a strong effect compared with infected untreated animals and the vancomycin-treated group. The wounds treated with dalbavancin showed robust epidermal coverage with reconstitution of the regular and keratinized epidermal lining and well-organized granulation tissue with numerous blood vessels, although slightly less than that in the uninfected group. While in the vancomycin-treated group the epithelium appeared, in general, still hypertrophic, the granulation tissue appeared even less organized. We observed elevated EGFR and VEGF expression in both treated groups, although it was higher in dalbavancin-treated mice. MMP-1 and MMP-9 were decreased in uninfected tissue and in both treated tissues compared with untreated infected wounds. This study showed faster healing with dalbavancin treatment that might be associated with higher EGFR and VEGF levels.

New Developments in Bacterial, Viral, and Fungal Cutaneous Infections

PURPOSE OF REVIEW

This review highlights clinically relevant updates to common and significant bacterial, viral, and fungal cutaneous infection within the past 5 years. Recent developments are presented so that the clinician may provide evidence-based, high-quality patient care.

RECENT FINDINGS

New resistance patterns in cutaneous pathogens have recently emerged as a result of inappropriate antimicrobial use. Several new FDA-approved antimicrobials have been approved to treat such infections, including multi-drug resistant pathogens. Several organizational guidelines for cutaneous infection management have been updated with new recommendations for screening, diagnostic, and treatment strategies.

SUMMARY

Clinicians should be aware of the most recent evidence and guidelines for the management of cutaneous infections in order to reduce the emergence of antimicrobial resistance and most effectively treat their patients.

A Multicenter Evaluation of Vancomycin-Associated Acute Kidney Injury in Hospitalized Patients with Acute Bacterial Skin and Skin Structure Infections

Background

We sought to determine the real-world incidence of and risk factors for vancomycin-associated acute kidney injury (V-AKI) in hospitalized adults with acute bacterial skin and skin structure infections (ABSSSI).

Methods

Retrospective, observational, cohort study at ten U.S. medical centers between 2015 and 2019. Hospitalized patients treated with vancomycin (≥ 72 h) for ABSSSI and ≥ one baseline AKI risk factor were eligible. Patients with end-stage kidney disease, on renal replacement therapy or AKI at baseline, were excluded. The primary outcome was V-AKI by the vancomycin guidelines criteria.

Results

In total, 415 patients were included. V-AKI occurred in 39 (9.4%) patients. Independent risk factors for V-AKI were: chronic alcohol abuse (aOR 4.710, 95% CI 1.929–11.499), no medical insurance (aOR 3.451, 95% CI 1.310–9.090), ICU residence (aOR 4.398, 95% CI 1.676–11.541), Gram-negative coverage (aOR 2.926, 95% CI 1.158–7.392) and vancomycin duration (aOR 1.143, 95% CI 1.037–1.260). Based on infection severity and comorbidities, 34.7% of patients were candidates for oral antibiotics at baseline and 39.3% had non-purulent cellulitis which could have been more appropriately treated with a beta-lactam. Patients with V-AKI had significantly longer hospital lengths of stay (9 vs. 6 days, p = 0.001), higher 30-day readmission rates (30.8 vs. 9.0%, p < 0.001) and increased all-cause 30-day mortality (5.1 vs. 0.3%, p = 0.024)

Conclusions

V-AKI occurred in approximately one in ten ABSSSI patients and may be largely prevented by preferential use of oral antibiotics whenever possible, using beta-lactams for non-purulent cellulitis and limiting durations of vancomycin therapy.

Electronic supplementary material

The online version of this article (10.1007/s40121-019-00278-1) contains supplementary material, which is available to authorized users.

Multicenter Study of the Real-World Use of Ceftaroline versus Vancomycin for Acute Bacterial Skin and Skin Structure Infections

The objective of this study was to determine if real-world ceftaroline treatment in adults hospitalized for acute bacterial skin and skin structure infections (ABSSSI) is associated with decreased infection-related length of stay (LOSinf) compared to that with vancomycin. This was a retrospective, multicenter, cohort study from 2012 to 2017. Cox proportional hazard regression, propensity score matching, and inverse probability of treatment weighting (IPTW) were used to determine the independent effect of treatment group on LOSinf The patients were adults hospitalized with ABSSSI and treated with ceftaroline or vancomycin for ≥72 h within 120 h of diagnosis at four academic medical centers and two community hospitals in Arizona, Florida, Michigan, and West Virginia. A total of 724 patients were included (325 ceftaroline treated and 399 vancomycin treated). In general, ceftaroline-treated patients had characteristics consistent with a higher risk of poor outcomes. The unadjusted median LOSinf values were 5 (interquartile range [IQR], 3 to 7) days and 6 (IQR, 4 to 8) days in the vancomycin and ceftaroline groups, respectively (hazard ratio [HR], 0.866; 95% confidence interval [CI], 0.747 to 1.002). The Cox proportional hazard model (adjusted HR [aHR], 0.891; 95% CI, 0.748 to 1.060), propensity score-matched (aHR, 0.955; 95% CI, 0.786 to 1.159), and IPTW (aHR, 0.918; 95% CI, 0.793 to 1.063) analyses demonstrated no significant difference in LOSinf between groups. Patients treated with ceftaroline were significantly more likely to meet criteria for discharge readiness at day 3 in unadjusted and adjusted analyses. Although discharge readiness at day 3 was higher in ceftaroline-treated patients, LOSinf values were similar between treatment groups. Clinical and nonclinical factors were associated with LOSinf.

Antimicrobial resistance, virulence genes profiling and molecular relatedness of methicillin-resistant Staphylococcus aureus strains isolated from hospitalized patients in Guangdong Province, China

PURPOSE

The main objective of this study was to decipher the prevalence, antimicrobial resistance, major virulence genes and the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolated from different clinical sources in southern China.

MATERIALS AND METHODS

The present study was performed on 187 non-duplicate S. aureus clinical isolates collected from three tertiary hospitals in Guangdong Province, China, 2010-2016. Antimicrobial susceptibility testing was performed by the disk diffusion method and by measuring the minimum inhibitory concentration. Screening for resistance and virulence genes was performed. Clonal relatedness was determined using various molecular typing methods such as multilocus sequence typing, spa and staphylococcal chromosomal cassette mec (SCCmec) typing. Whole genome sequencing was performed for three selected isolates.

RESULTS

Out of 187 isolates, 103 (55%) were identified as MRSA. The highest prevalence rate was found among the skin and soft tissue infection (SSTI) samples (58/103), followed by sputum samples (25/103), blood stream infection samples (15/103) and others (5/103). Antimicrobial susceptibility results revealed high resistance rates for erythromycin (64.1%), clindamycin (48.5%), gentamicin (36.9%) and ciprofloxacin (33.98%). All isolates were susceptible to vancomycin. Resistance genes and mutation detected were as follows: aac(6')-aph(2") (24.3%), dfrG (10.7%), rpoB (21.4%), cfr (0%), fexA (1.94%), gyrA (35.92%), gyrB (0.97%), grlA (20.4%), grlB (10.68%), ermA (21.4%), ermB (18.44%), ermC (21.4%) and lnuA (18.44%). Profiling of virulence genes revealed the following: sea (11.7%), seb (21.4%), sec (0.97%), sed (0.97%), hla (86.41%), hlb (17.48%), hlg (10.68%), hld (53.4%), Tsst-1 (3.9%) and pvl (27.2%). Clonal relatedness showed that ST239-SCCmecA III-t37 clone was the most prevalent clone.

CONCLUSION

Our study elucidated the prevalence, antibiotic resistance, pathogenicity and molecular characteristics of MRSA isolated from various clinical sources in Guangdong, China. We found that the infectious rate of MRSA was higher among SSTI than other sources. The most predominant genotype was ST239-SCCmecA III-t37 clone, indicating that ST239-t30 clone which was previously predominant had been replaced by a new clone.

Structure-activity relationships of pyrazole-4-carbodithioates as antibacterials against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of serious hospital-acquired infections and is responsible for significant morbidity and mortality in residential care facilities. New agents against MRSA are needed to combat rising resistance to current antibiotics. We recently reported 5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC) as a new bacteriostatic agent against MRSA that appears to act via a novel mechanism. Here, twenty nine analogs of HMPC were synthesized, their anti-MRSA structure-activity relationships evaluated and selectivity versus human HKC-8 cells determined. Minimum inhibitory concentrations (MIC) ranged from 0.5 to 64 μg/mL and up to 16-fold selectivity was achieved. The 4-carbodithioate function was found to be essential for activity but non-specific reactivity was ruled out as a contributor to antibacterial action. The study supports further work aimed at elucidating the molecular targets of this interesting new class of anti-MRSA agents.