Clinical and economic outcomes of oral linezolid versus intravenous vancomycin in the treatment of MRSA-complicated, lower-extremity skin and soft-tissue infections caused by methicillin-resistant Staphylococcus aureus

Efficacy and Safety of Different Antibiotic Therapies for Bone and Joint Infections: A Network Meta-analysis of Randomized Controlled Trials

BACKGROUND

Although an increasing number of antibiotics are being used to treat bone and joint infections, their specific efficacy remains controversial. Thus, we aimed to systematically compare the efficacy and safety of antibiotic therapies for orthopedic infections.

METHODS

PubMed, Embase, The Cochrane Library, and Web of Science databases were searched from inception to April 2022. Two authors independently and rigorously conducted the screening, data extraction, and quality assessment of the relevant studies. All the extracted data were evaluated using traditional metaanalysis and network meta-analysis by STATA SE 16.0.

RESULTS

A total of eleven randomized controlled trials (RCTs) involving 1,063 patients were included for data analysis. The analysis results from the NMA indicated that in terms of the clinical effectiveness rate, linezolid (OR: 1.75, 95% CI: 1.01 to 3.02) showed significant efficacy compared to ampicillin/sulbactam. With regard to the microbiological eradication rate, linezolid showed significant efficacy compared to cephalosporins (OR: 8.13, 95% CI: 1.16 to 57.09) and quinolones (OR: 3.51, 95% CI: 1.18 to 10.49). Similar findings were obtained for subgroup populations with diabetic foot infections (DFI). However, linezolid was significantly related to higher adverse events than ampicillin/sulbactam (OR: 3.25, 95% CI: 1.68 to 6.30) and cephalosporins (OR: 18.29, 95% CI: 1.59 to 209.76).

CONCLUSION

Linezolid appeared to be the most promising treatment regimen for staphylococcal bone and joint infections. However, due to the overall limited evidence, the research results need further high-quality RCTs for confirmation.

Efficacy and safety of optional parenteral antimicrobial therapy for complicated skin and soft tissue infections: A systematic review and Bayesian network meta-analysis

BACKGROUND

Skin and soft tissue infections (SSTIs) carry significant economic burden, as well as morbidity and mortality, especially when caused by methicillin-resistant Staphylococcus aureus. This study aims to investigate the efficacy and safety of optional antimicrobial therapy for the treatment of complicated SSTIs (cSSTIs).

METHODS

We searched PubMed, Medline (Via Ovid SP), Embase (Via Ovid SP), and the Cochrane Central Register of Controlled Trials from their inception to March 22, 2021 for randomized controlled trials (RCTs) that studied the use of optional antimicrobial therapy for cSSTIs. Citations' screening, study selection, data extraction, and risk of bias assessment were independently performed by 2 authors. The primary outcomes were clinical and microbiological treatment success, and adverse events (AEs) were also assessed.

RESULTS

A total of 48 trials covering 24,381 patients assessing 20 types of antimicrobial treatment modalities were included. Overall, omadacycline was associated with the highest beneficial effect on clinical and microbiological treatment success and with the largest rank probability based on surface under the cumulative ranking curve values, avarofloxacin was closely followed. Both had, however, omadacycline was related to moderately safety profiles. Lefamulin ranked as the best option was associated with the lowest risk of severe AEs. Subgroup analysis showed similar results. The quality of primary outcomes was moderate to low.

CONCLUSIONS

The use of omadacycline was associated with higher rates of clinical and microbiological treatment success for the treatment of cSSTIs, with a relative low risk of AEs. Due to the limitations of the included RCTs, high-quality and well-designed RCTs are needed to further confirm the results.

Impact of Empiric Linezolid for Necrotizing Soft Tissue Infections on Duration of Methicillin-Resistant Staphylococcus aureus-Active Therapy Empiric Linezolid Use for Necrotizing Soft Tissue Infections

Background: Necrotizing soft tissue infections (NSTIs) require prompt surgical debridement and antimicrobial therapy. Indicated antimicrobial therapy involves broad-spectrum coverage against common pathogens and toxin inhibition. Linezolid provides both methicillin-resistant Staphylococcus aureus (MRSA) coverage and toxin inhibition, however, there is limited evidence evaluating its role in empiric treatment. The purpose of this study was to evaluate the impact of empiric linezolid use for NSTIs on the total duration of MRSA-active therapy. Patients and Methods: This retrospective, single-center study included adult surgical intensive care unit (ICU) patients treated with empiric vancomycin and clindamycin or linezolid along with gram-negative and anaerobe coverage for NSTIs. The primary end point of this study was the duration of MRSA-active therapy. Secondary end points included ICU and hospital length of stay (LOS; days), new-onset acute kidney injury (AKI), and Clostridioides difficile infection (CDI). Results: There were 21 patients in the vancomycin/clindamycin cohort and 28 patients in the linezolid cohort. The average duration of vancomycin was 3.9 days versus 2.9 days of linezolid (p = 0.04). The average hospital LOS for the vancomycin/clindamycin cohort was somewhat longer than the linezolid cohort, although the difference was not statistically significant (p = 0.07), and the incidence of new-onset AKI during hospitalization was higher in the vancomycin/clindamycin cohort (38.1% vs. 0%; p < 0.001). No differences were observed for ICU LOS or CDI. Conclusions: Empiric linezolid use for NSTI was associated with one less day of MRSA-active therapy and lower incidence of new-onset AKI during hospitalization. Linezolid was a safe and effective alternative to vancomycin/clindamycin for empiric treatment of NSTIs.

Comparative efficacy of delafloxacin for complicated and acute bacterial skin and skin structure infections: results from a network meta-analysis

BACKGROUND

Delafloxacin is a novel fluoroquinolone with broad antibacterial activity against pathogens causing acute bacterial skin and skin structure infections (ABSSSI). This network meta-analysis (NMA) was conducted to evaluate the relative efficacy of delafloxacin versus other comparators used for managing patients with ABSSSI.

METHODS

A systematic literature review was conducted to identify randomised controlled trials (RCTs) evaluating adults (≥ 18 years) with ABSSSI, complicated SSSI (cSSSI), complicated skin and soft tissue infections (cSSTI) or severe cellulitis with pathogen of gram-positive, gram-negative, or mixed aetiology. OVID MEDLINE^®, Embase, Epub Ahead of Print, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews were searched from inception through 12 April 2019. A feasibility assessment was conducted, followed by an NMA, which was run in a Bayesian framework. The interventions included in the NMA encompassed monotherapy or combination therapies of amoxicillin/clavulanate, ampicillin/sulbactam, ceftaroline, ceftobiprole, dalbavancin, daptomycin, delafloxacin, fusidic acid, iclaprim, linezolid, omadacycline, oxacillin + dicloxacillin, standard therapy, tedizolid, telavancin, tigecycline, vancomycin, vancomycin + aztreonam and vancomycin + linezolid.

RESULTS

A feasibility assessment was performed and evidence networks were established for composite clinical response (n = 34 studies), early clinical response (n = 16 studies) and microbiological response (n = 14 studies) in the overall study population, composite clinical response (n = 4 studies) in obese subpopulation and for composite clinical response (n = 18 studies) and microbiological response (n = 14 studies) in patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. Delafloxacin performed significantly better than fusidic acid, iclaprim, vancomycin, and ceftobiprole for composite clinical response. Delafloxacin was comparable to dalbavancin, daptomycin, fusidic acid, iclaprim, linezolid, omadacycline, tedizolid, vancomycin, vancomycin + aztreonam and vancomycin + linezolid in the analysis of early clinical response, whereas for microbiological response, delafloxacin was comparable to all interventions. In the obese subpopulation, the results favoured delafloxacin in comparison to vancomycin, whilst the results were comparable with other interventions among the MRSA subpopulation.

CONCLUSIONS

Delafloxacin is a promising new antibiotic for ABSSSI demonstrating greater improvement (composite clinical response) compared to ceftobiprole, fusidic acid, iclaprim, telavancin and vancomycin and comparable effectiveness versus standard of care for all outcomes considered in the study.

Comparative Efficacy and Safety of Vancomycin, Linezolid, Tedizolid, and Daptomycin in Treating Patients with Suspected or Proven Complicated Skin and Soft Tissue Infections: An Updated Network Meta-Analysis

Introduction

Skin and soft structure infections (SSTIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) pose serious health risks and cause significant cost burdens, and a conclusive recommendation about antibiotics has not yet been generated. Therefore, we performed this updated network meta-analysis to determine the preferred drug for the treatment of MRSA-caused SSTIs.

Methods

We searched PubMed, Embase, and Cochrane Library to identify any potentially eligible randomized controlled trials (RCTs) investigating the comparative efficacy and safety of any two of vancomycin, linezolid, tedizolid, and daptomycin in MRSA-caused SSTIs. All statistical analyses were conducted with RevMan, ADDIS, and STATA software.

Results

Twenty eligible RCTs involving 7804 patients were included for the final analysis. Direct meta-analysis suggested that linezolid was superior to vancomycin in improving clinical (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.07–1.99; P = 0.02) and microbiological (OR, 1.89; 95% CI, 1.24–2.86; P = 0.003) success, which were all confirmed by network meta-analyses. No statistical differences were identified regarding other comparisons. Meanwhile, there were no significant differences between any two antibiotics related to safety. Moreover, ranking probabilities indicated that linezolid had the highest probability of being ranked best in terms of clinical and microbiological success.

Conclusion

Based on the limited evidence, linezolid may be a preferred antibiotic for the treatment of MRSA-caused SSTIs because it showed superiority in clinical and microbiological success without difference regarding safety.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00456-0.

Gaultheria longibracteolata, an alternative source of wintergreen oil

Gaultheria longibracteolata (Ericaceae) has been traditionally used by different linguistic groups in Yunnan Province, China, but it has not been well studied. Through our ethnobotanical study in Lüchun County of Yunnan, we found that this species has multiple traditional uses including food, medicine, and worship. The essential oils from the root, stem, and leaf were investigated by both GC-MS and anti-bacterial assays. The GC-MS study showed that methyl salicylate is the main (>90%) component of the essential oil, and the oil composition extracted from different plant parts showed some similarities. The oil of G. longibracteolata displayed antimicrobial activity against Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus, which is likely due to its methyl salicylate content. Gautheria longbracteolata appears to be a useful natural wintergreen oil substitute, but further studies are needed to develop this product.

An optimized method for the detection and spatial distribution of aminoglycoside and vancomycin antibiotics in tissue sections by mass spectrometry imaging

Suboptimal antibiotic dosing has been identified as one of the key drivers in the development of multidrug-resistant (MDR) bacteria that have become a global health concern. Aminoglycosides and vancomycin are broad-spectrum antibiotics used to treat critically ill patients infected by a variety of MDR bacterial species. Resistance to these antibiotics is becoming more prevalent. In order to design proper antibiotic regimens that maximize efficacy and minimize the development of resistance, it is pivotal to obtain the in situ pharmacokinetic-pharmacodynamic profiles at the sites of infection. Mass spectrometry imaging (MSI) is the ideal technique to achieve this. Aminoglycosides, due to their structure, suffer from poor ionization efficiency. Additionally, ion suppression effects by endogenous molecules greatly inhibit the detection of aminoglycosides and vancomycin at therapeutic levels. In the current study, an optimized method was developed that enabled the detection of these antibiotics by MSI. Tissue spotting experiments demonstrated a 5-, 15-, 35-, and 54-fold increase in detection sensitivity in the washed samples for kanamycin, amikacin, streptomycin, and vancomycin, respectively. Tissue mimetic models were utilized to optimize the washing time and matrix additive concentration. These studies determined the improved limit of detection was 40 to 5 μg/g of tissue for vancomycin and streptomycin, and 40 to 10 μg/g of tissue for kanamycin and amikacin. The optimized protocol was applied to lung sections from mice dosed with therapeutic levels of kanamycin and vancomycin. The washing protocol enabled the first drug distribution investigations of aminoglycosides and vancomycin by MSI, paving the way for site-of-disease antibiotic penetration studies.

Staphylococcal infections and infertility: mechanisms and management

Infertility is a subject of worldwide concern as it affects approximately 15% of couples. Among the prime contributors of infertility, urogenital bacterial infections have lately gained much clinical importance. Staphylococcal species are commensal bacteria and major human pathogens mediating an array of reproductive tract infections. Emerging evidences are 'bit by bit' revealing the mechanisms by which Staphylococci strategically disrupt normal reproductive functions. Staphylococcal species can directly or through hematogenous routes can invade the reproductive tissues. In the testicular cells, epididymis as well as in various compartments of female reproductive tracts, the pathogen recognition receptors, toll-like receptors (TLRs), can recognize the pathogen-associated molecular patterns on the Staphylococci and thereby activate inflammatory signalling pathways. These elicit pro-inflammatory mediators trigger other immune cells to infiltrate and release further inflammatory agents and reactive oxygen species (ROS). Adaptive immune responses may intensify the inflammation-induced reproductive tissue damage, particularly via activation of T-helper (Th) cells, Th1 and Th17 by the innate components or by staphylococcal exotoxins. Staphylococcal surface factors binding with sperm membrane proteins can directly impair sperm functions. Although Staphylococci, being one of the most virulent bacterial species, are major contributors in infection-induced infertility in both males and females, the mechanisms of their operations remain under-discussed. The present review aims to provide a comprehensive perception of the possible mechanisms of staphylococcal infection-induced male and female infertility and aid potential interventions to address the lack of competent therapeutic measures for staphylococcal infection-induced infertility.

[Modern problems of modelling and treatment of soft tissues abscesses]

Increase of the frequency of soft tissues pyoinflammatory diseases and purulent-septic complications against the background the antibiotic-resistance of organism dictates the necessity of search of rational new surgical technologies and preparations with the intense bactericidal effect. Period of the connective tissue (cicatrix) formation on a place of wound defect of the operated purulent abscess of soft tissue (PAST) is defined by the speed of the granulations and epithelial tissue formation. Therefore, one of the task of experimental surgery is search of new methods of the effective postoperative influence on terms of the regeneration and complete obliteration of the PAST cavity. The perspective direction in treatment of surgical infection is application of metals nanoparticles. In treatment of pyoinflammatory processes it is applied the preparation Eplan and also zinc oxide nanoparticles which have bactericidal, antiinflammatory and regenerative effects. However, till now it was not carried out experimental works on modelling and surgical treatment of PAST with local application of the laser technologies in combinations with Eplan and metals nanoparticles.

Linezolid and Rifampicin Combination to Combat cfr-Positive Multidrug-Resistant MRSA in Murine Models of Bacteremia and Skin and Skin Structure Infection

Linezolid resistance mediated by the cfr gene in MRSA represents a global concern. We investigated relevant phenotype differences between cfr-positive and -negative MRSA that contribute to pathogenesis, and the efficacy of linezolid-based combination therapies in murine models of bacteremia and skin and skin structure infection (SSSI). As a group, cfr-positive MRSA exhibited significantly reduced susceptibilities to the host defense peptides tPMPs, human neutrophil peptide-1 (hNP-1), and cathelicidin LL-37 (P < 0.01). In addition, increased binding to fibronectin (FN) and endothelial cells paralleled robust biofilm formation in cfr-positive vs. -negative MRSA. In vitro phenotypes of cfr-positive MRSA translated into poor outcomes of linezolid monotherapy in vivo in murine bacteremia and SSSI models. Importantly, rifampicin showed synergistic activity as a combinatorial partner with linezolid, and the EC₅₀ of linezolid decreased 6-fold in the presence of rifampicin. Furthermore, this combination therapy displayed efficacy against cfr-positive MRSA at clinically relevant doses. Altogether, these data suggest that the use of linezolid in combination with rifampicin poses a viable therapeutic alternative for bacteremia and SSSI caused by cfr-positive multidrug resistant MRSA.

Potential savings through single-dose intravenous Dalbavancin in long-term MRSA infection treatment - a health economic analysis using German DRG data

Complicated infections such as osteomyelitis, skin and soft tissue infections or endocarditis often require antibiotic therapies that can last up to several weeks. The prolonged hospital length of stay (LOS) leads to a dramatic increase in costs. Single-dose intravenous Dalbavancin is a novel antimicrobial agent for the treatment of acute bacterial skin, skin structure and soft tissue infections (ABSSSI) that allows an earlier discharge of patients, resulting in potential savings. Joint, bone and prostheses infections (JBPI) are also related with long LOS. The aim of this study is to determine the economic effects of single-dose intravenous Dalbavancin in suitable patients with Methicillin-resistant Staphylococcus aureus infections in Germany. For this purpose, an analysis with real-world patient treatment data was performed, which was subsequently validated in a large German hospital. In total, ABSSSI patients with MRSA infections could stay 6.45 days shorter and 2,865 € could be saved while JBPI patients could be discharged eventually 10.6 days earlier and 3,909 € could be saved. Single-dose intravenous Dalbavancin is thus an option for patients with ABSSSI and JBPI who are eligible for discharge.

Optimizing skin and skin structure infection outcomes: considerations of cost of care

INTRODUCTION

Skin and skin structure infections (SSSIs) refer to a collection of clinical infectious syndromes involving layers of skin and associated soft tissues. Although associated with less morbidity and mortality than other common skin infections, SSSIs represent a significant increasing source of healthcare expense, with a prevalence of 500 episodes per 10,000 patient-years in the United States resulting in burdening health care systems, of approximately $6 billion annually.

AREAS COVERED

Opportunities to reduce costs of care associated with SSSI are highlighted, including transitions of care and avoiding unnecessary hospital admissions. Moreover, we reviewed new antibiotics (e.g. single dose glycopeptides), and the impact of consulting specialists in the emergency department on SSSI treatment outcomes.

EXPERT COMMENTARY

New healthcare models and payment strategies combined with new therapeutics are challenging norms of care. Newer drugs to treat skin infections can move a substantive percent of patients previously admitted to hospital care to the outpatient setting. Additionally, patients can be managed with oral or one time intravenous regimens, improving the likelihood of patient adherence and satisfaction. These variables need to be weighed against added acquisition costs and the development of thoughtful algorithms is needed to direct care and optimize treatment, cost, and patient satisfaction.

Efficacy and safety of linezolid compared with other treatments for skin and soft tissue infections: a meta-analysis

Linezolid with other treatments for skin and soft tissue infections (SSTIs) has been evaluated in several studies. However, the conclusions remain controversial. By searching PubMed, EMBASE, and Cochrane library databases, we conducted a meta-analysis to evaluate linezolid and other treatments for skin and soft tissue infections. The study was summarized, and the risk ratio (RR) and its 95% confidence interval (CI) were calculated. Eleven related articles were included in the meta-analysis. Our results revealed that linezolid was associated with a significantly better clinical (RR = 1.09, 95% CI: 1.02–1.16, P_{heterogeneity} = 0.326, I² = 13.0%) and microbiological cure rates (RR = 1.08, 95% CI: 1.01–1.16, P_{heterogeneity} = 0.089, I² = 41.7%) when comparing with vancomycin. There was no significant difference in the incidence of anemia, nausea, and mortality; however, the incidence of vomiting, diarrhea, and thrombocytopenia in patients treated with linezolid is significantly higher than that with other treatments. Our study confirmed that linezolid seems to be more effective than vancomycin for treating people with SSTIs. It is recommended that linezolid be monitored for thrombocytopenia, vomiting, and diarrhea. Further studies with larger dataset and well-designed models are required to validate our findings.

The role of methicillin-resistant Staphylococcus aureus in skin and soft tissue infections

PURPOSE OF REVIEW

Methicillin-resistant Staphylococcus aureus (MRSA) has become a major public health issue worldwide over the last years. MRSA is frequently implicated in the development of skin and soft tissue infections, leading to significant increases in morbidity, mortality and overall healthcare costs.

RECENT FINDINGS

In order to face the threat of MRSA, major changes in clinical management of skin and soft tissue infections are required. The identification of populations at risk for the acquisition of infections due to MRSA, together with the improvement of the diagnostic techniques, is paramount. Moreover, a number of new antimicrobials with activity against MRSA have been recently developed and approved for the treatment of skin and soft tissue infections, however, the use of the new drugs in the wide clinical practice remains limited.

SUMMARY

We reviewed the current epidemiology of MRSA in skin and soft tissue infections, with particular focus on implications for clinical management. The potential role of new antibiotic options against MRSA infections is also discussed.

Comparative efficacy and safety of antibiotics used to treat acute bacterial skin and skin structure infections: Results of a network meta-analysis

OBJECTIVE

This NMA compared the efficacy and safety between IV antibiotics that are used in the current standard of care for managing adult patients (≥18 years of age) with ABSSSI.

METHODS

Comparators were chosen on the basis that both direct and indirect comparisons between the interventions of interest could be performed. Outcomes of the analysis were selected on the basis that they are frequently measured and reported in trials involving ABSSSI patients, and only published randomised control trials of any size and duration and with any blinding status were eligible for inclusion in the analysis. The NMA was performed using both a fixed-effect and random-effect model. Efficacy-related endpoints were (1) clinical treatment success and (2) microbiological success at TOC visit. Safety-related endpoints were (1) number of discontinuations due to AEs/SAEs, (2) patients experiencing AEs, (3) patients experiencing SAEs and (4) all-cause mortality.

RESULTS

Study interventions included daptomycin, dalbavancin, linezolid and tigecycline. Vancomycin was the comparator in all studies, except in two where it was linezolid and teicoplanin. The NMA showed that irrespective of patient subgroup, the likelihood of clinical and microbiological success with dalbavancin was statistically similar to the comparators studied. No statistically significant differences were observed between dalbavancin and any of the comparators in the discontinuation rate due to AEs/SAEs. In contrast, dalbavancin was associated with a significantly lower likelihood of experiencing an AE than linezolid, a significantly lower likelihood of experiencing a SAE than vancomycin and daptomycin, and a significantly lower risk of all-cause mortality than vancomycin, linezolid and tigecycline.

CONCLUSION

Dalbavancin affords a promising, new alternative IV antimicrobial agent which is as effective as traditional therapies, but with the added benefit of enabling clinicians to treat patients with ABSSSI in different organisational settings. Notwithstanding, any introduction of an effective treatment with a differential mode of administration into healthcare systems must be followed by a change in clinical practice and patient management in order to fully achieve desirable economic outcomes.

Systematic review and network meta-analysis of tedizolid for the treatment of acute bacterial skin and skin structure infections caused by MRSA

BACKGROUND

Tedizolid, the active moiety of tedizolid phosphate, is approved in the United States, the European Union, Canada and a number of other countries for the treatment of acute bacterial skin and skin structure infections (ABSSSI) caused by certain susceptible bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). This network meta-analysis (NMA) evaluates the comparative effectiveness of tedizolid and other antibacterials indicated for the treatment of ABSSSI caused by MRSA.

METHODS

Systematic review of 10 databases was undertaken to inform an NMA to estimate the relative effectiveness of tedizolid and established monotherapy comparators (ceftaroline, daptomycin, linezolid, teicoplanin, tigecycline, vancomycin) for treating MRSA-associated ABSSSI. Randomized controlled trials enrolling adults with ABSSSI or complicated skin and skin structure infections caused by suspected/documented MRSA were eligible for inclusion. Networks were developed based on similarity of study design, patient characteristics, outcome measures and available data. Outcomes of interest included clinical response at end of therapy (EOT), post-therapy evaluation (PTE) or test-of-cure assessment and treatment discontinuations resulting from adverse events (AEs). Bayesian NMA was conducted for each outcome using fixed-effects and random effects models.

RESULTS

Literature searches identified 3,618 records; 15 trials met the inclusion criteria and were considered suitable for NMA comparison. In fixed-effects models, tedizolid had higher odds of clinical response at EOT (odds ratio [OR], 1.7; credible interval, 1.0, 3.0) and PTE than vancomycin (OR, 1.6; credible interval, 1.1, 2.5). No differences in odds of clinical response at EOT or PTE were observed between tedizolid and other comparators. There was no evidence of a difference among treatments for discontinuation due to AEs. Results from random effects and fixed-effects models were generally consistent.

CONCLUSIONS

Tedizolid was superior to vancomycin for clinical response at EOT and PTE. There was no evidence of a difference between tedizolid and other comparators and no evidence of a difference between tedizolid and all comparators when evaluating discontinuation due to AEs. These findings suggest that tedizolid provides an alternative option for the management of serious skin infections caused by suspected or documented MRSA. This study is subject to the limitations inherent in all NMAs, and the results should be interpreted accordingly.

Linezolid: a promising option in the treatment of Gram-positives

Linezolid, an oxazolidinone antimicrobial agent that acts by inhibiting protein synthesis in a unique fashion, is used in the treatment of community-acquired pneumonia, skin and soft-tissue infections and other infections caused by Gram-positive bacteria including VRE and methicillin-resistant staphylococci. Currently, linezolid resistance among these pathogens remains low, commonly <1.0%, although the prevalence of antibiotic resistance is increasing in many countries. Therefore, the development of resistance by clinical isolates should prompt increased attention of clinical laboratories to routinely perform linezolid susceptibility testing for this important agent and should be taken into account when considering its therapeutic use. Considering the importance of linezolid in the treatment of infections caused by Gram-positive bacteria, this review was undertaken to optimize the clinical use of this antibiotic.

Infectious Diseases: Pharmacologic Treatment Options for Nosocomial Pneumonia Involving Methicillin-Resistant Staphylococcus aureus

Objective:

To discuss current and potential treatment options for nosocomial pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA).

Data Sources:

A MEDLINE search (1966–January 2007) was conducted to identify English-language literature on pharmacotherapy of nosocomial pneumonia and the bibliographies of pertinent articles. Programs and abstracts from infectious disease meetings were also searched. Search terms included MRSA, nosocomial pneumonia, pulmonary infections, vancomycin, quinupristin/dalfopristin, linezolid, daptomycin, tigecycline, dalbavancin, oritavancin, and ceftobiprole.

Data Selection and Data Extraction:

All articles were critically evaluated and all pertinent information was included in this review.

Data Synthesis:

Vancomycin has been the drug of choice for MRSA infections for many years. Recent data suggest that linezolid may be superior to vancomycin in the treatment of MRSA nosocomial pneumonia. However, there are limitations to the available data. Therefore, prospective, randomized studies are needed before linezolid is recommended as the preferred first-line therapy. Other approved agents for nosocomial MRSA infections, such as quinupristin/dalfopristin and daptomycin, should not be used in the treatment of MRSA pneumonia, as they were inferior in clinical trials. Tigecycline has excellent activity against MRSA in vitro, but should not be routinely used for the treatment of MRSA pneumonia, as clinical data are lacking. In a Phase III clinical trial, an anti-MRSA cephalosporin, ceftobiprole, is being evaluated for effectiveness against nosocomial pneumonia. Investigational glycopeptides may eventually have a role in the treatment of nosocomial pneumonia, but data are currently lacking.

Conclusions:

Vancomycin is still the drug of choice for treatment of MRSA pneumonia, and linezolid should be used as an alternative agent. Linezolid should carry strong consideration for patients with vancomycin-induced nephrotoxicity or a documented lack of response to vancomycin. Tigecycline and investigational agents with activity against MRSA may be future options for nosocomial pneumonia due to MRSA.

New therapeutic options for skin and soft tissue infections

PURPOSE OF REVIEW

The occurrence of methicillin-resistance in Staphylococcus aureus, that represents the most frequent cause of complicated skin and soft tissue infections (cSSTIs) worldwide, is a major concern and has been associated with increased length of stay, health care costs, and overall mortality. Although vancomycin is still considered the standard therapy in this setting, limitations of its use in clinical practice are represented by a progressive increase in methicillin-resistant S. aureus (MRSA) minimum inhibitory concentrations, drug-related toxicity, and the lack of an oral formulation. New therapeutic options for MRSA cSSTIs have recently become available, with promising implications for the management of cSSTIs in clinical practice.

RECENT FINDINGS

A number of new antimicrobials with activity against MRSA have been recently approved for the treatment of cSSTIs, and other agents are under investigation. We have reviewed the recent developments, with a specific focus on the possible advantages of new drugs for the management of cSSTIs into the everyday clinical practice.

SUMMARY

The new approved drugs for the treatment of cSSTIs are expected to offer many advantages for the management of patients with suspected or confirmed MRSA cSSTIs. The most promising features of the new compounds include the availability of oral formulations, once-weekly intravenous regimens, and broad spectra of activity.

Comparison of protein-chip array analysis and traditional ELISAs for biomarker detection of diabetic limb arterial stenosis

The aim of this study was to screen the biomarkers of diabetic limb arterial stenosis. Fasting blood samples of 40 patients with diabetic limb arterial stenosis (experimental group), 40 diabetes patients (diabetic control group), and 40 healthy individuals (healthy control group) were collected. Protein-chip assay analysis and ELISA were used to detect tumor necrosis factor α, interleukin-6, endothelin-1, calcitonin gene-related peptide and high-sensitivity C-reactive protein in the three groups. Protein-chip array analysis and ELISA found consistent results that endothelin-1, tumor necrosis factor α, interleukin-6 and high-sensitivity C-reactive protein in the experimental group were significantly up-regulated while the expression of calcitonin gene-related peptide was down-regulated compared with the healthy control group ( P < 0.01). When compared with the diabetic control group, only markedly increased calcitonin gene-related peptide and interleukin-6 were observed in the experimental group ( P < 0.01). The study suggests that high-throughput protein-chip may be a reliable method to screen biomarkers of diabetic limb arterial stenosis. Calcitonin gene-related peptide and interleukin-6 might be promising biomarkers for diabetic limb arterial stenosis.

Methicillin-resistant Staphylococcus aureus infections: A review of the currently available treatment options

This review is the result of discussions that took place at the 5th MRSA Working Group Consensus Meeting and explores the possible treatment options available for different types of infections due to methicillin-resistant Staphylococcus aureus (MRSA), focusing on those antibiotics that could represent a valid alternative to vancomycin. In fact, whilst vancomycin remains a viable option, its therapy is moving towards individualised dosing. Other drugs, such as the new lipoglycopeptides (oritavancin, dalbavancin and telavancin) and fifth-generation cephalosporins (ceftaroline and ceftobiprole), are showing good in vitro potency and in vivo efficacy, especially for patients infected with micro-organisms with higher vancomycin minimum inhibitory concentrations (MICs). Tedizolid is an attractive agent for use both in hospital and community settings, but the post-marketing data will better clarify its potential. Daptomycin and linezolid have shown non-inferiority to vancomycin in the treatment of MRSA bacteraemia and non-inferiority/superiority to vancomycin in the treatment of hospital-acquired pneumonia. Thus, several options are available, but more data from clinical practice, especially for invasive infections, are needed to assign specific roles to each antibiotic and to definitely include them in the new antibacterial armamentarium.

Hot topics in the diagnosis and management of skin and soft-tissue infections

Eighteen hot topics regarding the diagnosis and management of skin and soft-tissue infections (SSTIs) were selected and reviewed by members of the SSTI Working Group of the International Society of Chemotherapy (ISC). Despite the large amount of literature available on the issue selected, there are still many unknowns with regard to many of them and further studies are required to answer these challenging issues that face clinicians on a daily basis.

Linezolid versus vancomycin for skin and soft tissue infections

BACKGROUND

The morbidity and treatment costs associated with skin and soft tissue infections (SSTIs) are high. Linezolid and vancomycin are antibiotics that are commonly used in treating skin and soft-tissue infections, specifically those infections due to methicillin-resistant Staphylococcus aureus (MRSA).

OBJECTIVES

To compare the effects and safety of linezolid and vancomycin for treating people with SSTIs.

SEARCH METHODS

For this first update of this review we conducted searches of the following databases: Cochrane Wounds Group Specialised Register (searched 24 March 2015; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. We also contacted manufacturers for details of unpublished and ongoing trials. We scrutinised citations within all obtained trials and major review articles to identify any additional trials.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing linezolid with vancomycin in the treatment of SSTIs.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias and extracted data. The primary outcomes were clinical cure, microbiological cure, and SSTI-related and treatment-related mortality. We performed subgroup analyses according to age, and whether the infection was due to MRSA.

MAIN RESULTS

No new trials were identified for this first update. We included nine RCTs (3144 participants). Linezolid was associated with a significantly better clinical (RR 1.09, 95% CI 1.03 to 1.16) and microbiological cure rate in adults (RR 1.08, 95% CI 1.01 to 1.16). For those infections due to MRSA, linezolid was significantly more effective than vancomycin in clinical (RR 1.09, 95% CI 1.03 to 1.17) and microbiological cure rates (RR 1.17, 95% CI 1.04 to 1.32). No RCT reported SSTI-related and treatment-related mortality. There was no significant difference in all-cause mortality between linezolid and vancomycin (RR 1.44, 95% CI 0.75 to 2.80). There were fewer incidents of red man syndrome (RR 0.04, 95% CI 0.01 to 0.29), pruritus (RR 0.36, 95% CI 0.17 to 0.75) and rash (RR 0.27, 95% CI 0.12 to 0.58) in the linezolid group compared with vancomycin, however, more people reported thrombocytopenia (RR 13.06, 95% CI 1.72 to 99.22), and nausea (RR 2.45, 95% CI 1.52 to 3.94) when treated with linezolid. It seems, from the available data, that length of stay in hospital was shorter for those in the linezolid group than the vancomycin group. The daily cost of outpatient therapy was less with oral linezolid than with intravenous vancomycin. Although inpatient treatment with linezolid cost more than inpatient treatment with vancomycin per day, the median length of hospital stay was three days shorter with linezolid. Thus, total hospital charges per patient were less with linezolid treatment than with vancomycin treatment.

AUTHORS' CONCLUSIONS

Linezolid seems to be more effective than vancomycin for treating people with SSTIs, including SSTIs caused by MRSA. The available evidence is at high risk of bias and is based on studies that were supported by the pharmaceutical company that makes linezolid. Further well-designed, independently-funded, RCTs are needed to confirm the available evidence.

Economic evaluation among Chinese patients with nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus and treated with linezolid or vancomycin: a secondary, post-hoc analysis based on a Phase 4 clinical trial study

OBJECTIVE

To assess cost-effectiveness of linezolid vs vancomycin in treating nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA-NP) in China and the impact of renal failure on healthcare resource utilization (HCRU) and costs.

METHODS

Cost-effectiveness analysis was conducted based on data from the ZEPHyR trial, with efficacy measured by treatment success and costs calculated from HCRU. Confidence intervals (CI) for cost, efficacy and incremental cost-effectiveness ratios (ICER) were calculated by non-parametric bootstrap. Chi-square test was used for renal failure rate and t-test for HCRU/cost comparisons. Impact of renal failure was assessed using regression model.

RESULTS

Data from 448 patients (1:1 linezolid:vancomycin) were analyzed. More patients treated with linezolid achieved success (55% [95% CI = 48-62%]) than with vancomycin (45% [38-52%]). Treatment cost were ¥79,551 (95% CI = ¥72,421-¥86,680) for linezolid vs ¥77,587 (¥70,656-¥84,519) for vancomycin in Beijing, ¥90,995 (¥82,598-¥99,393) vs ¥89,448 (¥81,295-¥97,601) in Guangzhou, ¥82,383 (¥74,956-¥89,810) vs ¥80,799 (¥73,545-¥88,054) in Nanjing and ¥59,413 (¥54,366-¥64,460) vs ¥57,804 (¥52,613-¥62,996) in Xi'an. Per successful treatment, the ICER of linezolid over vancomycin were ¥19,719 (-¥143,553 to ¥320,980) (Beijing), ¥15,532 (-¥185,411 to ¥349,693) (Guangzhou), ¥15,904 (-¥161,935 to ¥314,987) (Nanjing) and ¥16,145 (-¥100,738 to ¥234,412) (Xi'an). From simulations, the majority of linezolid cases had greater efficacy and higher costs and more than one third had greater efficacy and lower costs. More vancomycin patients developed renal failure (15% vs 4%, p < 0.001). Patients with renal failure had higher cost (Nanjng: ¥100,449 (SD = ¥65,080) vs ¥74,944 (SD = ¥49,632), p = 0.002).

CONCLUSION

Linezolid was more cost-effective than vancomycin in treating MRSA-NP from a Chinese payer's perspective, and associated with less renal failure, HCRU and cost.

Comparative efficacy of antibiotics for the treatment of acute bacterial skin and skin structure infections (ABSSSI): a systematic review and network meta-analysis

OBJECTIVE

The objective was to conduct a systematic review and network meta-analysis (NMA) of existing treatments for ABSSSI focusing on the novel lipoglycopeptide oritavancin.

METHODS

EMBASE, MEDLINE, MEDLINE in Process, CENTRAL (Cochrane), and select conferences were searched for randomized controlled trials investigating antimicrobial agents for the treatment of ABSSSI. NMA was used to estimate the odds ratios of the Test-Of-Cure (TOC) and Early Clinical Response (ECR) outcomes for treatments relative to vancomycin in the ITT populations. Sub-group analyses in MRSA and MSSA populations were conducted for TOC; sensitivity analyses investigated the use of the clinically evaluable (CE) populations and the restriction to trials following the recent FDA guidelines for clinical trials.

RESULTS

The systematic review identified 52 trials. The most commonly investigated treatments were vancomycin and linezolid; most trials reported TOC, but not ECR. The posterior mean and 95% credible intervals for odds ratios of TOC for antimicrobial agents relative to vancomycin were: linezolid (1.55; 0.91-2.57), daptomycin (2.18; 0.90-5.42), and oritavancin 1200 mg (1.06; 0.80-1.43). The odds ratio of ECR for oritavancin 1200 mg was 1.02 (0.23-4.33). In the MRSA sub-group the odds ratios relative to vancomycin for TOC were: linezolid (1.55; 0.96-2.46), daptomycin (0.74; 0.13-3.66), and oritavancin 1200 mg (0.94; 0.44-2.02). In the MSSA sub-group they were linezolid (1.36; 0.15-13.34) and oritavancin 1200 mg (0.82; 0.08-7.83). These results were robust to the sensitivity analyses.

CONCLUSIONS

This NMA provides a unified framework for the comparison of all available antimicrobial agents used in the treatment of ABSSSI and is the first to assess the ECR end-point. The results suggest equivalence of clinical efficacy between vancomycin, daptomycin, linezolid, and novel antimicrobial agents including oritavancin for the treatment of ABSSSI at TOC. The wide uncertainty margins indicate the heterogeneity of the available evidence and the need for further research.

Systematic Review and Meta-Analysis To Estimate Antibacterial Treatment Effect in Acute Bacterial Skin and Skin Structure Infection

A systematic literature review and meta-analysis were conducted to estimate the antibacterial treatment effect for linezolid and ceftaroline to inform on the design of acute bacterial skin and skin structure infection (ABSSSI) noninferiority trials. The primary endpoints included an early clinical treatment response (ECTR) defined as cessation of lesion spread at 48 to 72 h postrandomization and the test-of-cure (TOC) response defined as total resolution of the infection at 7 to 14 days posttreatment. The systematic review identified no placebo-controlled trials in ABSSSI, 4 placebo-controlled trials in uncomplicated skin and soft tissue infection as a proxy for placebo in ABSSSI, 12 linezolid trials in ABSSSI, 3 ceftaroline trials in ABSSSI, and 2 trials for nonantibacterial treatment. The ECTR rates at 48 to 72 h and corresponding 95% confidence intervals (CI) were 78.7% (95% CI, 61.1 to 96.3%) for linezolid, 74.0% (95% CI, 69.7 to 78.3%) for ceftaroline, and 59.0% (95% CI, 52.8 to 65.3%) for nonantibacterial treatment. The early clinical treatment effect could not be estimated, given no available placebo or proxy for placebo data for this endpoint. Clinical, methodological, and statistical heterogeneity influenced the selection of trials for the meta-analysis of the TOC treatment effect estimation. The pooled estimates of the TOC treatment response were 31.0% (95% CI, 6.2 to 55.9%) for the proxy for placebo, 88.1% (95% CI, 81.0 to 95.1%) for linezolid, and 86.1% (95% CI, 83.7 to 88.6%) for ceftaroline. The TOC clinical treatment effect estimation was 25.1% for linezolid and 27.8% for ceftaroline. The antibacterial treatment effect estimation at TOC will inform on the design and analysis of future noninferiority ABSSSI clinical trials.

Profile of tedizolid phosphate and its potential in the treatment of acute bacterial skin and skin structure infections

Tedizolid phosphate is the first once-daily oxazolidinone approved by the United States Food and Drug Administration for the treatment of acute bacterial skin and skin structure infections (ABSSSI). It is more potent in vitro than linezolid against methicillin-resistant Staphylococcus aureus (MRSA) and other gram-positive pathogens causing ABSSSI, even retaining activity against some linezolid-resistant strains. Tedizolid is approximately 90% protein bound, leading to lower free-drug concentrations than linezolid. The impact of the effect of food, renal or hepatic insufficiency, or hemodialysis on tedizolid's pharmacokinetic have been evaluated, and no dosage adjustment is needed in these populations. In animal and clinical studies, tedizolid's effect on bacterial killing is optimized by the free-drug area under the curve to minimum inhibitory concentration ratio (fAUC/MIC). The 200 mg once-daily dose is able to achieve the target fAUC/MIC ratio in 98% of simulated patients. Two Phase III clinical trials have demonstrated the noninferiority of tedizolid 200 mg once daily for 6 days to linezolid 600 mg twice daily for 10 days. In vitro, animal, and clinical studies have failed to demonstrate that tedizolid inhibits monoamine oxidase to a clinically relevant extent. Tedizolid has several key advantages over linezolid including once daily dosing, decreased treatment duration, minimal interaction with serotonergic agents, possibly associated with less adverse events associated with the impairment of mitochondrial protein synthesis (eg, myelosuppression, lactic acidosis, and peripheral/optic neuropathies), and retains in vitro activity against linezolid-resistant gram-positive bacteria. Economic analyses with tedizolid are needed to describe the cost-effectiveness of this agent compared with other options used for ABSSSI, particularly treatment options active against MRSA.

Economic features of antibiotic resistance: the case of methicillin-resistant Staphylococcus aureus

This paper analyses and updates the economic information regarding methicillin-resistant Staphylococcus aureus (MRSA), including information that has been previously reviewed by other authors, and new information, for the purpose of facilitating health management and clinical decisions. The analysed articles reveal great disparity in the economic burden on MRSA patients; this is mainly due to the diversity of the designs of the studies, as well as the variability of the patients and the differences in health care systems. Regarding prophylactic strategies, the studies do not provide conclusive results that could unambiguously orientate health management. The studies addressing treatments noted that linezolid seems to be a cost-effective treatment for MRSA, mostly because it is associated with a shorter length of stay (LOS) in hospital. However, important variables such as antimicrobial susceptibility, infection type and resistance emergence should be included in these analyses before a conclusion is reached regarding which treatment is the best (most efficient). The reviewed studies found that rapid MRSA detection, using molecular techniques, is an efficient technique to control MRSA. As a general conclusion, the management of MRSA infections implicates important economic costs for hospitals, as they result in higher direct costs and longer LOS than those related to methicillin-susceptible S. aureus (MSSA) patients or MRSA-free patients; there is wide variability in those increased costs, depending on different variables. Moreover, the research reveals a lack of studies on other related topics, such as the economic implications of changes in MRSA epidemiology (community patients and lineages associated with farm animals).

Treatment of Gram-positive infections in critically ill patients

Gram-positive bacteria to include methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible Staphylococcus aureus (MSSA), and enterococci, to include vancomycin-resistant enterococci (VRE), display a remarkable array of resistance and virulence factors, which have contributed to their prominent role in infections of the critically ill. Over the last three decades infections with these pathogens has increased as has their overall resistance to available antimicrobial agents. This has led to the development of a number of new antibiotics for the treatment of Gram-positive bacteria. At present, it is important that clinicians recognize the changing resistance patterns and epidemiology of Gram-positive bacteria as these factors may impact patient outcomes. The increasing range of these pathogens, such as the emergence of community-associated MRSA clones, emphasizes that all specialties of physicians treating infections should have a good understanding of the infections caused by Gram-positive bacteria in their area of practice. When initiating empiric antibiotics, it is of vital importance that this therapy be timely and appropriate, as delays in treatment are associated with adverse outcomes. Although vancomycin has traditionally been considered a first-line therapy for serious MRSA infections, multiple concerns with this agent have opened the door for alternative agents demonstrating efficacy in this role. Similarly, the expansion of VRE as a pathogen in the ICU setting has required the development of agents targeting this important pathogen.

Antibacterial Treatment of Meticillin-Resistant Staphylococcus Aureus Complicated Skin and Soft Tissue Infections: a Cost and Budget Impact Analysis in Greek Hospitals

Introduction

Meticillin-resistant staphylococcus aureus (MRSA) is an important cause of antimicrobial-resistant infections worldwide. Its prevalence remains high in the Greek hospital setting. Complicated skin and soft tissue infections (cSSTIs) due to MRSA are associated with prolonged hospitalization, additional healthcare costs and significant morbidity. The purpose of this study was to conduct a cost analysis and a budget impact analysis relative to different management scenarios for MRSA-cSSTIs from a hospital perspective.

Methods

Equal efficacy was assumed for the pharmacotherapies under evaluation and resource use was elicited via an expert panel of seven local infectious disease specialists. The model was based on a previously published economic model that was adapted for the Greek hospital setting and included a decision tree for the management of hospitalized patients with MRSA-cSSTIs, which simulated costs and outcomes for the duration of hospitalization according to the therapeutic scenario. Inpatient costs consisted of hospitalization, diagnostic/laboratory testing, physician visits and antibiotic treatment.

Results

Current economic impact of MRSA-cSSTIs for the inpatient setting in Greek hospitals was estimated at €29,196,218. Total per patient cost according to first-line agent was €2,457, €2,762, €2,850, €3,494 and €3,094 and mean length of stay was 9.2, 12.5, 10.3, 13.0 and 14.0 days for linezolid, vancomycin, daptomycin, tigecycline, and teicoplanin, respectively. An estimated 10,287 MRSA-cSSTI patients are treated annually in Greek hospitals. Thus, increasing the use of linezolid by 11% over a 3-year period (current use 19%; 3 year projection 30%), for the management of MRSA-cSSTIs, could result in 3-year savings of €896,065.

Conclusion

Management of MRSA-cSSTI requires intensive resource use; overall healthcare costs differ according to the chosen first-line treatment. In light of considerable budget constraints, development of hospital strategies which facilitate early discharge, such as the introduction of clinical criteria and guidelines for switching from intravenous to oral MRSA-cSSTI therapy, could result in substantial savings for the Greek hospital budget.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0044-8) contains supplementary material, which is available to authorized users.

Vancomycin Minimum Inhibitory Concentration for Methicillin-Resistant Staphylococcus aureus Infections; Is There Difference in Mortality Between Patients?

BACKGROUND

New data indicates that vancomycin may be less effective against methicillin-resistant Staphylococcus aureus (MRSA) infections with minimum inhibition concentration (MIC) within a sensitive range.

OBJECTIVES

The aim of this study was to determine the distribution of the vancomycin MIC between MRSA strains and observe the difference in mortality between patients, while the influence of changes in MIC on the efficacy of vancomycin was also examined.

PATIENTS AND METHODS

A routine date-based study was conducted on 41 MRSA isolates in a hospital in Tehran, Iran. The isolates were assessed for MIC by using the E-test method, and results were categorized into three groups: A (MIC < 1.5 μg/mL), B (1.5 ≤ MIC < 2 μg/mL) and C (MIC ≥ 2 μg/mL) MRSA.

RESULTS

Group A was the most common group, followed by groups C and B. Although there was no statistically significant difference between patients' mortality with the MIC group, the mortality rate of group A was higher than C and B.

CONCLUSIONS

Regarding Clinical and Laboratory Standards Institute (CLSI) definition for vancomycin susceptibility (MIC < 2 μg/mL), it seems that vancomycin may not be considered as the best antibiotic in order to treat heteroresistant vancomycin intermediate S. aureus (hVISA) and vancomycin sensitive S. aureus (VSSA) infections, and a new breakpoint for vancomycin and alternative antibiotics should be considered.

Novel antibiotic treatment for skin and soft tissue infection

PURPOSE OF REVIEW

Acute bacterial skin and skin structure infection (ABSSSI) is a common and significant indication for antibiotic treatment. The microbial aetiology is becoming more resistant to available antibiotics and the treatment of patients is additionally challenged by extremes of age, obesity, diabetes and other co-morbidities. This review examines recent antimicrobial developments.

RECENT FINDINGS

In many parts of the world, multidrug-resistant (MDR) staphylococci are the predominant cause of ABSSSI in both the community and in hospital. Increasing resistance in Gram-negative organisms presents problems in the management of surgical-site infections. Most new antibiotics have been developed to treat MDR Gram-positive bacteria and there are few agents to treat infections caused by MDR Gram-negative pathogens.

SUMMARY

A number of novel agents are available clinically, with other agents of related chemical structure under development. There are no entirely new classes of antibiotics. Maintaining the efficacy of antimicrobial treatment require effective antibiotic stewardship, good infection prevention and the development of further new antibiotics.

Cost-Effectiveness of Linezolid versus Vancomycin among Patients with Methicillin-Resistant Staphylococcus aureus Confirmed Nosocomial Pneumonia in China

OBJECTIVE

To estimate the cost-effectiveness of intravenous linezolid as a first-line agent against intravenous vancomycin in treating methicillin-resistant Staphylococcus aureus-confirmed nosocomial pneumonia in four Chinese cities.

METHODS

A decision-analytic model of 4-week time horizon was used to conduct cost-effectiveness analyses from the payer's perspective. Clinical outcomes and resource use data were derived from a head-to-head trial, supplemented with local cost estimates based on hospital data via an expert panel. A series of scenario analyses were conducted to evaluate the impact of uncertainty around model inputs. All results were reported in 2012 Chinese Renminbi.

RESULTS

The predicted probability of overall treatment success was 0.629 and 0.602 for linezolid and vancomycin, respectively. Total inpatient costs varied across the four cities, ranging from ¥58,835 to ¥86,894 for linezolid and ¥58,390 to ¥87,033 for vancomycin, respectively. Linezolid was demonstrated to be a dominant treatment strategy in Guangzhou. In Beijing, Nanjing, and Xi'an, incremental cost-effectiveness ratios in terms of additional successfully treated patient were ¥1,861, ¥163, and ¥16,509, respectively. Dominance by linezolid was observed in some scenario analyses with parameters such as treatment duration, inclusion of cost of managing adverse events, and drug acquisition costs being the main drivers of cost-effectiveness results.

CONCLUSIONS

Despite linezolid's higher drug acquisition cost, its superior clinical efficacy renders it a likely cost-effective alternative for the treatment of methicillin-resistant Staphylococcus aureus-confirmed nosocomial pneumonia as compared with branded vancomycin from the payer perspectives of Beijing, Guangzhou, Nanjing, and Xi'an.

Linezolid versus vancomycin for skin and soft tissue infections

BACKGROUND

The morbidity and treatment costs associated with skin and soft tissue infections (SSTIs) are high. Linezolid and vancomycin are antibiotics that are commonly used in treating skin and soft-tissue infections, specifically those infections due to methicillin-resistant Staphylococcus aureus (MRSA).

OBJECTIVES

To compare the effects and safety of linezolid and vancomycin for treating people with SSTIs.

SEARCH METHODS

In May 2013 we conducted searches of the following databases: Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. We also contacted manufacturers for details of unpublished and ongoing trials. We scrutinised citations within all obtained trials and major review articles to identify any additional trials.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing linezolid with vancomycin in the treatment of SSTIs.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias and extracted data. The primary outcomes were clinical cure, microbiological cure, and SSTI-related and treatment-related mortality. We performed subgroup analyses according to age, and whether the infection was due to MRSA.

MAIN RESULTS

We included nine RCTs (3144 participants). Linezolid was associated with a significantly better clinical (RR 1.09, 95% CI 1.03 to 1.16) and microbiological cure rate in adults (RR 1.08, 95% CI 1.01 to 1.16). For those infections due to MRSA, linezolid was significantly more effective than vancomycin in clinical (RR 1.09, 95% CI 1.03 to 1.17) and microbiological cure rates (RR 1.17, 95% CI 1.04 to 1.32). No RCT reported SSTI-related and treatment-related mortality. There was no significant difference in all-cause mortality between linezolid and vancomycin (RR 1.44, 95% CI 0.75 to 2.80). There were fewer incidents of red man syndrome (RR 0.04, 95% CI 0.01 to 0.29), pruritus (RR 0.36, 95% CI 0.17 to 0.75) and rash (RR 0.27, 95% CI 0.12 to 0.58) in the linezolid group compared with vancomycin, however, more people reported thrombocytopenia (RR 13.06, 95% CI 1.72 to 99.22), and nausea (RR 2.45, 95% CI 1.52 to 3.94) when treated with linezolid. It seems, from the available data, that length of stay in hospital was shorter for those in the linezolid group than the vancomycin group. The daily cost of outpatient therapy was less with oral linezolid than with intravenous vancomycin. Although inpatient treatment with linezolid cost more than inpatient treatment with vancomycin per day, the median length of hospital stay was three days shorter with linezolid. Thus, total hospital charges per patient were less with linezolid treatment than with vancomycin treatment.

AUTHORS' CONCLUSIONS

Linezolid seems to be more effective than vancomycin for treating people with SSTIs, including SSTIs caused by MRSA. The available evidence is at high risk of bias and is based on studies that were supported by the pharmaceutical company that makes linezolid. Further well-designed, independently-funded, RCTs are needed to confirm the available evidence.

Vancomycin: does it still have a role as an antistaphylococcal agent?

The recognition of the shortcomings of vancomycin as an antistaphylococcal agent, together with the burgeoning availability of alternative effective antistaphylococcal antibiotics, has led to a reassessment of the role of this glycopeptide antimicrobial in clinical therapeutics. Evidence indicates that vancomycin is inferior to semisynthetic penicillins in the treatment of infections due to methicillin-susceptible Staphylococcus aureus. Additional evidence suggests that vancomycin may be inferior to some comparator agents in the treatment of infections due to methicillin-resistant S. aureus (MRSA). While high-level resistance remains rare, data from some centers suggest an evolutionary change in S. aureus, evidenced by reduced susceptibility to vancomycin. This, together with the problem of heteroresistance to vancomycin, as well as poor tissue penetration after its systemic administration, presents potential obstacles to the successful therapy of S. aureus infections with this glycopeptide. While it has been suggested that these problems may be overcome by administration of vancomycin in much higher doses, the efficacy and safety of this approach remains to be determined and will require randomized clinical trials for its demonstration. A number of novel agents with activity against MRSA have been introduced to clinical practice in the last 2 years and others are still in the investigational stage. Despite the fact that these newer agents have been compared with vancomycin in trials only designed to demonstrate noninferiority, some potential evidence of superiority over vancomycin has emerged. While the relative roles of each of these newer agents and vancomycin can only be determined definitively by performance of adequately powered randomized clinical trials, current evidence suggests that vancomycin may be an inferior therapeutic agent.

Role of linezolid in the treatment of complicated skin and soft tissue infections

Staphylococcus aureus is the most common cause of complicated skin and soft tissue infections (cSSTIs). Antibiotic choices for these infections continue to evolve. History has seen penicillin progress to antistaphylococcal penicillins and cephalosporins, but these drugs are now giving way to drugs that are effective against methicillin-resistant S. aureus (MRSA). While vancomycin has been the gold standard to treat MRSA infections, newer therapeutic options have been developed over the last 5 years. These include quinupristin-dalfopristin, daptomycin, tigecycline and linezolid, which is the focus for this review. Linezolid is efficacious in the treatment of cSSTIs (including diabetic foot infections) caused by Gram-positive organisms (including MRSA), with a well-defined safety profile and straightforward dosing. It is also approved for nosocomial pneumonia, community-acquired pneumonia and uncomplicated skin and skin structure infections. Linezolid has an oral and parenteral formulation, which are equivalent. The oral formulation has the potential to offer economic benefits as compared with other therapies. Currently, there are only a few new antibiotics in development with MRSA activity. The proper use of all antibiotics, including these newer agents, is increasingly important if we are to slow the evolution of microbial resistance.

Treatment of infections due to resistant Staphylococcus aureus

This chapter reviews data on the treatment of infections caused by drug-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). This review covers findings reported in the English language medical literature up to January of 2013. Despite the emergence of resistant and multidrug-resistant S. aureus, we have seven effective drugs in clinical use for which little resistance has been observed: vancomycin, quinupristin-dalfopristin, linezolid, tigecycline, telavancin, ceftaroline, and daptomycin. However, vancomycin is less effective for infections with MRSA isolates that have a higher MIC within the susceptible range. Linezolid is probably the drug of choice for the treatment of complicated MRSA skin and soft tissue infections (SSTIs); whether it is drug of choice in pneumonia remains debatable. Daptomycin has shown to be non-inferior to either vancomycin or β-lactams in the treatment of staphylococcal SSTIs, bacteremia, and right-sided endocarditis. Tigecycline was also non-inferior to comparator drugs in the treatment of SSTIs, but there is controversy about whether it is less effective than other therapeutic options in the treatment of more serious infections. Telavancin has been shown to be non-inferior to vancomycin in the treatment of SSTIs and pneumonia, but has greater nephrotoxicity. Ceftaroline is a broad-spectrum cephalosporin with activity against MRSA; it is non-inferior to vancomycin in the treatment of SSTIs. Clindamycin, trimethoprim-sulfamethoxazole, doxycycline, rifampin, moxifloxacin, and minocycline are oral anti-staphylococcal agents that may have utility in the treatment of SSTIs and osteomyelitis, but the clinical data for their efficacy is limited. There are also several drugs with broad-spectrum activity against Gm-positive organisms that have reached the phase II and III stages of clinical testing that will hopefully be approved for clinical use in the upcoming years: oritavancin, dalbavancin, omadacycline, tedizolid, delafloxacin, and JNJ-Q2. Thus, there are currently many effective drugs to treat resistant S. aureus infections and many promising agents in the pipeline. Nevertheless, S. aureus remains a formidable adversary, and despite our deep bullpen of potential therapies, there are still frequent treatment failures and unfortunate clinical outcomes. The following discussion summarizes the clinical challenges presented by MRSA, the clinical experience with our current anti-MRSA antibiotics, and the gaps in our knowledge on how to use these agents to most effectively combat MRSA infections.

Cost comparison of linezolid versus vancomycin for treatment of complicated skin and skin-structure infection caused by methicillin-resistant Staphylococcus aureus in Quebec

BACKGROUND

In Canada, complicated skin and skin-structure infection (cSSSI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is usually treated with antibiotics in hospital, with a follow-up course at home for stable patients. The cost implications of using intravenous and oral linezolid instead of intravenous vancomycin in Canadian clinical practice have not been examined.

OBJECTIVES

To evaluate the potential treatment cost impact for the Quebec health care system of linezolid versus vancomycin for MRSA-related cSSSI therapy, using a net impact analysis approach.

METHODS

Health care resource use associated with linezolid and vancomycin therapy was estimated for patients in Quebec, based on expert opinion. Costs were assigned to health care resources (antibiotics, medical supplies, laboratory testing and health care professional time) based on unit prices. The base-case analysis assumed 14 days of antibiotic treatment for both agents; five days in hospital followed by nine days at home. Therapy duration, length of inpatient treatment and discharge rates were varied in sensitivity analyses.

RESULTS

Antibiotic costs were higher for linezolid than for vancomycin, for both inpatient ($874 versus $144, respectively) and outpatient therapy ($1,356 versus $1,242, respectively). Compared with vancomycin, lower costs for antibiotic preparation, administration and monitoring of linezolid offset drug acquisition costs. Total treatment costs were $3,850 for linezolid versus $5,189 for vancomycin. Results were sensitive to the number of treatment days spent at home and the discharge rate.

CONCLUSION

Using linezolid instead of vancomycin to treat MRSA-related cSSSI, for hospital and home courses combined, may reduce health care resource utilization and costs in Quebec.

Antibiotic therapy for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) in non surgical wounds

BACKGROUND

Non surgical wounds include chronic ulcers (pressure or decubitus ulcers, venous ulcers, diabetic ulcers, ischaemic ulcers), burns and traumatic wounds. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation (i.e. presence of MRSA in the absence of clinical features of infection such as redness or pus discharge) or infection in chronic ulcers varies between 7% and 30%. MRSA colonisation or infection of non surgical wounds can result in MRSA bacteraemia (infection of the blood) which is associated with a 30-day mortality of about 28% to 38% and a one-year mortality of about 55%. People with non surgical wounds colonised or infected with MRSA may be reservoirs of MRSA, so it is important to treat them, however, we do not know the optimal antibiotic regimen to use in these cases.

OBJECTIVES

To compare the benefits (such as decreased mortality and improved quality of life) and harms (such as adverse events related to antibiotic use) of all antibiotic treatments in people with non surgical wounds with established colonisation or infection caused by MRSA.

SEARCH METHODS

We searched the following databases: The Cochrane Wounds Group Specialised Register (searched 13 March 2013); The Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2); Database of Abstracts of Reviews of Effects (2013, Issue 2); NHS Economic Evaluation Database (2013, Issue 2); Ovid MEDLINE (1946 to February Week 4 2013); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, March 12, 2013); Ovid EMBASE (1974 to 2013 Week 10); EBSCO CINAHL (1982 to 8 March 2013).

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) comparing antibiotic treatment with no antibiotic treatment or with another antibiotic regimen for the treatment of MRSA-infected non surgical wounds. We included all relevant RCTs in the analysis, irrespective of language, publication status, publication year, or sample size.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified the trials, and extracted data from the trial reports. We calculated the risk ratio (RR) with 95% confidence intervals (CI) for comparing the binary outcomes between the groups and planned to calculate the mean difference (MD) with 95% CI for comparing the continuous outcomes. We planned to perform the meta-analysis using both fixed-effect and random-effects models. We performed intention-to-treat analysis whenever possible.

MAIN RESULTS

We identified three trials that met the inclusion criteria for this review. In these, a total of 47 people with MRSA-positive diabetic foot infections were randomised to six different antibiotic regimens. While these trials included 925 people with multiple pathogens, they reported the information on outcomes for people with MRSA infections separately (MRSA prevalence: 5.1%). The only outcome reported for people with MRSA infection in these trials was the eradication of MRSA. The three trials did not report the review's primary outcomes (death and quality of life) and secondary outcomes (length of hospital stay, use of healthcare resources and time to complete wound healing). Two trials reported serious adverse events in people with infection due to any type of bacteria (i.e. not just MRSA infections), so the proportion of patients with serious adverse events was not available for MRSA-infected wounds. Overall, MRSA was eradicated in 31/47 (66%) of the people included in the three trials, but there were no significant differences in the proportion of people in whom MRSA was eradicated in any of the comparisons, as shown below.1. Daptomycin compared with vancomycin or semisynthetic penicillin: RR of MRSA eradication 1.13; 95% CI 0.56 to 2.25 (14 people).2. Ertapenem compared with piperacillin/tazobactam: RR of MRSA eradication 0.71; 95% CI 0.06 to 9.10 (10 people).3. Moxifloxacin compared with piperacillin/tazobactam followed by amoxycillin/clavulanate: RR of MRSA eradication 0.87; 95% CI 0.56 to 1.36 (23 people).

AUTHORS' CONCLUSIONS

We found no trials comparing the use of antibiotics with no antibiotic for treating MRSA-colonised non-surgical wounds and therefore can draw no conclusions for this population. In the trials that compared different antibiotics for treating MRSA-infected non surgical wounds, there was no evidence that any one antibiotic was better than the others. Further well-designed RCTs are necessary.

Economic burden of inpatient and outpatient antibiotic treatment for methicillin-resistant Staphylococcus aureus complicated skin and soft-tissue infections: a comparison of linezolid, vancomycin, and daptomycin

Background

Previous economic analyses evaluating treatment of methicillin-resistant Staphylococcus aureus (MRSA) complicated skin and soft-tissue infections (cSSTI) failed to include all direct treatment costs such as outpatient parenteral antibiotic therapy (OPAT). Our objective was to develop an economic model from a US payer perspective that includes all direct inpatient and outpatient costs incurred by patients with MRSA cSSTI receiving linezolid, vancomycin, or daptomycin.

Methods

A 4-week decision model was developed for this economic analysis. Published literature and database analyses with validation by experts provided clinical, resource use, and cost inputs on data such as efficacy rate, length of stay, adverse events, and OPAT services. Base-case analysis assumed equal efficacy and equal length of stay for treatments. We conducted several sensitivity analyses where assumptions on resource use or efficacy were varied. Costs were reported in year-end 2011 US dollars.

Results

Total treatment costs in the base-case were lower for linezolid ($10,571) than vancomycin ($11,096), and daptomycin ($13,612). Inpatient treatment costs were $740 more, but outpatient costs, $1,266 less with linezolid than vancomycin therapy due to a switch to oral linezolid when the patient was discharged. Compared with daptomycin, both inpatient and outpatient treatment costs were lower with linezolid by $87 and $2,954 respectively. In sensitivity analyses, linezolid had lower costs compared with vancomycin and daptomycin when using differential length of stay data from a clinical trial, and using success rates from a meta-analysis. In a scenario without peripherally inserted central catheter line costs, linezolid became slightly more expensive than vancomycin (by $285), but remained less costly than daptomycin (by $2,316).

Conclusion

Outpatient costs of managing MRSA cSSTI may be reduced by 30%–50% with oral linezolid compared with vancomycin or daptomycin. Results from this analysis support potential economic benefit and cost savings of using linezolid versus traditional OPAT when total inpatient and outpatient medical costs are evaluated.