Use of a Silver-Containing Hydrofiber Dressing for Filling Abscess Cavity Following Incision and Drainage in the Emergency Department: A Randomized Controlled Trial

Effectiveness of silver and iodine dressings on wound healing: a systematic review and meta-analysis

OBJECTIVE

To evaluate the effects of silver and iodine dressings on healing time, healing rate, exudate amount, pain and anti-infective efficacy.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Databases including PubMed, Cochrane Library, Embase, Web of Science and CINAHL were surveyed up to May 2024.

ELIGIBILITY CRITERIA

Randomised controlled trials comparing silver and iodine dressings on wound healing in humans.

DATA EXTRACTION AND SYNTHESIS

Evidence certainty was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Data extraction was done independently by two reviewers, with the risk of bias assessed using the Cochrane tool. Narrative synthesis was performed to evaluate the effects of silver and iodine dressings on healing time, healing rate, pain, exudate amount and anti-infective efficacy. Meta-analysis using Review Manager V.5.4 calculated standardised mean differences for healing time and relative risks for rate to quantify the impacts of the treatments.

RESULTS

17 studies (18 articles) were included. The meta-analysis indicated that silver dressings significantly reduced healing time compared with iodine dressings (SMD=-0.95, 95% CI -1.62 to -0.28, I2=92%, p=0.005, moderate-quality evidence), with no significant difference in enhancing healing rate (RR=1.29, 95% CI 0.90 to 1.85, I2=91%, p=0.16, low-quality evidence). Based on low-quality evidence, for exudate amount (3/17), 66.7% (2/3) of the studies favoured silver dressings over iodine in reducing exudate volume. For pain (7/17), 57.1% (4/7) of the studies reported no significant difference between silver and iodine dressings, while 42.9% (3/7) studies indicated superior pain relief with silver dressings. For anti-infective efficacy (11/13), 54.5% (6/11) of the studies showed equivalence between silver and iodine dressings, while 36.4% (4/11) suggested greater antibacterial efficacy for silver.

CONCLUSION

Silver dressings, demonstrating a comparable healing rate to iodine dressings, significantly reduce healing time, suggesting their potential as a superior adjunct in wound care.

PROSPERO REGISTRATION NUMBER

CRD42020199602.

Microbiology of Facial Skin Infections-Strains, Susceptibility, and Therapeutic Consequences

BACKGROUND

Skin and soft tissue infections (SSTIs) are common conditions with severe and potentially life-threatening outcomes. However, the use of antibiotics to treat these infections is controversial.

PURPOSE

This study was to identify the microorganisms responsible for facial SSTIs, their antibiotic sensitivities, and the therapeutic outcomes of treatment.

STUDY DESIGN, SETTING, AND SAMPLE

This was a retrospective, observational cohort study conducted at a single oral and maxillofacial plastic surgery department. The study sample included 103 patients with facial SSTIs (61 men, 42 women) with a mean age of 41.8 years (standard deviation ± 20.4).

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLES

The predictor variables included patient characteristics, antibiotic use before the clinic visit, and the infection's site and origin.

MAIN OUTCOME VARIABLE(S)

The primary outcome variable was the presence of antibiotic resistance in the bacterial strains isolated from the infections.

METHODS

The data were collected by reviewing the results of microbiological swabs and patient records obtained from patients with facial SSTIs. Categorical variables were described using absolute and relative frequencies, and continuous variables were described using mean and standard deviation. The association between antibiotic resistance and the predictor variables was analyzed using Pearson's χ² test and student's t test.

RESULTS

The most common cause of SSTI was an infected epidermal cyst (60.1%). Of all the microorganisms identified, 80.6% were Gram-positive, and 55.8% showed antibiotic resistance against one or more of the evaluated antibiotics, including several backup antibiotics. There were no identified risk factors that significantly influenced the probability of resistance, and there were no adverse events observed.

CONCLUSION

The results of this study suggest that surgery should be the primary approach for treating SSTIs, as antibiotic administration may not be effective due to the unknown susceptibility of the causative strains. Antibiotics should be reserved for severe cases and high-risk patients, and if deemed necessary for SSTI management, a broad-spectrum antibiotic should be administered to cover resistant organisms.

Undressing the choice of dressings

There is a vast number of wound dressings to choose from, which can make selecting the most suitable dressing for a wound a daunting prospect. This article highlights how the wound can guide the doctor's decision. Although all wound dressings are intended to achieve optimal wound healing and protection from contamination, they do so to varying degrees depending on the qualities of the dressing and the wound itself. This article looks at a range of dressings, from traditional to newer dressings, and evaluates their benefits and contraindications to help determine where they are best suited for use in wound management.

Calculated initial parenteral treatment of bacterial infections: Skin and soft tissue infections

This is the ninth chapter of the guideline "Calculated Parenteral Initial Therapy of Adult Bacterial Disorders - Update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The chapter contains the first German S2k guidelines for bacterial skin and soft tissue infections. They encompass recommendations on diagnosis and treatment of the defined entities erysipelas (caused by beta-hämolytic streptococci), limited superficial cellulitis (S. aureus), severe cellulitis, abscess, complicated skin and soft tissue infections, infections of feet in diabetic patients ("diabetic foot"), necrotizing soft tissue infection and bite injuries.

S2k guidelines for skin and soft tissue infections Excerpts from the S2k guidelines for "calculated initial parenteral treatment of bacterial infections in adults - update 2018"

These first German S2k guidelines for bacterial skin and soft tissue infections were developed as one chapter of the recommendations for "calculated initial parenteral treatment of bacterial infections" issued under the auspices of the Paul-Ehrlich Society, of which the main part is presented here. Well-calculated antibiotic therapies require precise diagnostic criteria. Erysipelas is defined as non-purulent infection considered to be caused by beta-hemolytic strepto-cocci. It is diagnosed clinically by its bright-red erythema and early fever or chills at disease onset. Penicillin is the treatment of choice. Limited soft tissue infection (cellulitis) is usually caused by Staphylococcus (S.) aureus, frequently originates from chronic wounds and presents with a more violaceous-red hue and only rarely with initial fever or chills. Treatment consists of first- or second--generation cephalosporins or flucloxacillin (IV). Severe cellulitis is a purulent, partially necrotic infection which extends through tissue boundaries to fascias and requires surgical management in addition to antibiotics. Moreover, it frequently fulfills the criteria for "complicated soft tissue infections", as previously defined by the Food and Drug Administration for use in clinical trials (they include comorbidities such as uncontrolled diabetes, peripheral artery disease, neutropenia). It requires antibiotics which besides S. aureus target anaerobic and/or gramnegative bacteria. The rare so-called necrotizing skin and soft tissue infections represent a distinct entity. They are characterized by rapid, life-threatening progression due to special bacterial toxins that cause ischemic necrosis and shock and need rapid and thorough debridement in addition to appropriate antibiotics. For cutaneous abscesses the first-line treatment is adequate drainage. Additional antibiotic therapy is required only under certain circumstances (e.g., involvement of the face, hands, or anogenital region, or if drainage is somehow complicated). The present guidelines also contain consensus-based recommendations for higher doses of antibiotics than those approved or usually given in clinical trials. The goal is to deliver rational antibiotic treatment that is both effective and well-tolerated and that exerts no unnecessary selection pressure in terms of multidrug resistance.

International survey evaluating treatment of primary superficial skin abscesses

INTRODUCTION

Skin and soft-tissue infections (SSTI) present regularly as cutaneous abscesses which require surgical drainage. These abscesses often affect younger patients and interfere with their independency substantially. Existing guidelines display heterogeneous recommendations concerning surgical aftercare. Primary aim of this survey was to present a nomogram for standard abscess therapy based on international expert opinions.

METHOD

An online survey dealing with standard of care protocols for cutaneous abscesses concerning surgical treatment and aftercare was created. The survey was conducted in 2017 during two international conferences held in Switzerland.

RESULT

490 surgeons originating from 66 nations participated in this survey with the majority coming from Europe and Asia. Indication for surgery, operation type, and wound rinsing were answered homogeneously. Perioperative setting (45% sterile, 55% semi-sterile), anesthesia (45% local, 55% general), antibiotic therapy (38% always, 35% never, 27% other), irrigation fluid (54% sterile, 32% non-sterile, 14% antiseptic), irrigation frequency (55% once daily, 30% twice daily), and wound dressing (69% packing, 31% coverage) were heterogeneously answered topics.

CONCLUSION

Treatment and aftercare of simple primary skin abscesses are processed heterogeneously throughout the world. Focus should be on optimal patient focused treatment with minimal socio-economic impact. Future studies should focus on the validation of the different postoperative treatment options with the aim to develop a socio-economically accepted algorithm.

Management of complicated skin and soft tissue infections with a special focus on the role of newer antibiotics

Complicated skin and soft tissue infections (cSSTIs) represent the severe form of infectious disease that involves deeper soft tissues. Involvement of methicillin-resistant Staphylococcus aureus (MRSA) further complicates cSSTI with increased hospitalization, health care costs, and overall mortality. Various international guidelines provide recommendations on the management of cSSTIs, with the inclusion of newer antibiotics. This literature-based review discusses the overall management of cSSTI, including appropriate use of antibiotics in clinical practice. Successful treatment of cSSTIs starts with early and precise diagnosis, including identification of causative pathogen and its load, determination of infection severity, associated complications, and risk factors. The current standard-of-care for cSSTIs involves incision, drainage, surgical debridement, broad-spectrum antibiotic therapy, and supportive care. In recent years, the emergence of newer antibiotics (eg, ceftaroline, tigecycline, daptomycin, linezolid, etc) has provided clinicians wider options of antimicrobial therapy. Selection of antibiotics should be based on the drug characteristics, effectiveness, safety, and treatment costs, alongside other aspects such as host factors and local multidrug resistance rates. However, larger studies on newer antibiotics are warranted to refine the decision making on the appropriate antimicrobial therapy. Local Antimicrobial Stewardship Program strategies in health care settings could guide clinicians for early initiation of specific treatments to combat region-specific antimicrobial resistance, minimize adverse effects, and to improve outcomes such as reduction in Clostridium difficile infections. These strategies involving iv-to-oral switch, de-escalation to narrow-spectrum antibiotics, and dose optimization have an impact on the overall improvement of cSSTI therapy outcomes, especially in countries like Singapore that has a high disease burden.

Reduction in Central Line-Associated Bloodstream Infections Correlated With the Introduction of a Novel Silver-Plated Dressing for Central Venous Catheters and Maintained for 6 Years

OBJECTIVE

To assess a novel silver-plated dressing (SD) for central venous catheters in comparison to chlorhexidine gluconate-impregnated sponge (CHGIS) dressings in preventing central line-associated bloodstream infections (CLABSIs) in adult intensive care unit (ICU) patients.

DESIGN

Retrospective cohort study.

SETTING

Tampa General Hospital, an academic medical tertiary care center.

PATIENTS

All adult ICU patients of an academic medical tertiary care center from January 2009 to December 2010.

MEASUREMENTS AND MAIN RESULTS

A total of 3189 patient records were studied from 7 different ICUs during the 2-year period. Patients received either CHGIS dressings (January 2009-December 2009) or SDs (January 2010-December 2010). Primary outcomes measured were CLABSI rates per 1000 catheter days and ICU length of stay. There were 30 696 catheter days with CHGIS dressings and 31 319 catheter days with SDs. There was a statistically significant decrease in the rate of CLABSI per 1000 catheter days in the SD group, from 2.38 to 1.28 ( P = .001), with an absolute risk reduction of 1.1. There was a significantly lower incidence in the rate of CLABSI per 1000 catheter days in the SD group (incidence rate ratio [IRR] = 0.54, 95% confidence interval [CI]: 0.36-0.80). The relative risk of CLABSI in the SD group was 0.502 (95% CI: 0.340-0.730; P < .001). If SDs are used on all catheters, the decreased rate of CLABSIs observed would calculate to a cost savings of US$4070 to US$39 600 per 1000 catheter days. After successful implementation of the SD, we observed significant reductions in CLABSI rates and a sustained reduction in the subsequent 6 years.

CONCLUSION

Use of SDs is associated with a significant decrease in CLABSI rates in adult ICU patients compared to CHGIS dressings, with an estimated cost savings of US$4070 to US$39 600 per 1000 catheter days.

Simple Wound Irrigation in the Postoperative Treatment for Surgically Drained Spontaneous Soft Tissue Abscesses: Study Protocol for a Prospective, Single-Blinded, Randomized Controlled Trial

Background

Skin abscesses are a frequent encountered health care problem and lead to a significant source of morbidity. They consequently have an essential impact on the quality of life and work. To date, the type of aftercare for surgically drained abscesses remains under debate. This leads to undesirable practice variations. Many clinical standard protocols include sterile wound dressings twice a day by a home-care service to reduce the chance of a recurrent wound infection. It is unknown, however, whether reinfection rates are comparable to adequate wound irrigation with a nonsterile solution performed by the patient. Our hypothesis is that simple wound irrigation with nonsterile water for postoperative wound care after an abscess is surgically drained is feasible. We assume that in terms of reinfection and reintervention rates unsterile wound irrigation is equal to sterile wound irrigation.

Objective

The primary aim of this study is therefore to investigate if there is a need for sterile wound irrigation after surgically drained spontaneous skin abscesses.

Methods

In a prospective, randomized controlled, single-blinded, single-center trial based on a noninferiority design, we will enroll 128 patients randomized to either the control or the intervention group. The control group will be treated according to our current, standard protocol in which all patients receive a sterile wound irrigation performed by a home-care service twice a day. Patients randomized to the intervention group will be treated with a nonsterile wound irrigation (shower) twice a day. All patients will have a routine clinical control visit after 1, 3, 6, and 12 weeks in the outpatient clinic. Primary outcome is the reinfection and reoperation rate due to insufficient wound healing diagnosed either at the outpatient control visit or during general practitioner visits. Secondary outcome measures include a Short Form Health Survey, Visual Analog Scale, Patient and Observer Scar Assessment Scale, Vancouver Scar Scale, and the EurolQol 5-Dimension Questionnaire. Those questionnaires will be completed at the outpatient control visits.

Results

The trial was started in June 2016 and enrolled 50 patients by article publication. Regarding the adherence to our protocol, we found 10% of loss to follow-up until now. Only 2 patients needed reoperation and only 1 patient needed a change of treatment (antiseptic therapy). Most patients are happy with their randomized treatment but as expected some patients in the sterile group complained about timing problems with their working hours and home-care service appointments. Most patients in the nonsterile group are satisfied being able to take care of their wounds independently although some patients still depend on the home-care service for the wound dressing. We are hoping to have enrolled enough patients by summer 2017. The follow-up will take until autumn 2017, and study results are expected to be published by the end of 2017. This trial is solely supported by the cantonal hospital of Lucerne.

Conclusions

Nonsterile wound irrigation is more likely to be carried out independently by the patient than sterile wound irrigation. Therefore, if nonsterile wound care shows comparable results in terms of reinfection and reintervention rates, patient independence in the aftercare of surgically drained abscesses will increase, patients can return to work earlier, and health care costs can be reduced. In a preliminary, conservative estimation of health care costs, an annual savings of 300,000 CHF will be achieved in our hospital.

Trial Registration

German Clinical Trials Register DRKS00010418; https://drks-neu.uniklinik-freiburg.de/ drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00010418 (Archived by WebCite at http://www.webcitation.org/6q0AXp5EX)

Internal dressings for healing perianal abscess cavities

BACKGROUND

A perianal abscess is a collection of pus under the skin, around the anus. It usually occurs due to an infection of an anal gland. In the UK, the annual incidence is 40 per 100,000 of the adult population, and the standard treatment is admission to hospital for incision and drainage under general anaesthetic. Following drainage of the pus, an internal dressing (pack) is placed into the cavity to stop bleeding. Common practice is for community nursing teams to change the pack regularly until the cavity heals. Some practitioners in the USA and Australia make a small stab incision under local anaesthetic and place a catheter into the cavity which drains into an external dressing. It is removed when it stops draining. Elsewhere in the USA, simple drainage is performed in an outpatient setting under local anaesthetic.

OBJECTIVES

To assess the effects of internal dressings in healing wound cavities resulting from drainage of perianal abscesses.

SEARCH METHODS

In May 2016 we searched: The Cochrane Wounds 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 Plus. We also searched clinical trial registries to identify ongoing and unpublished studies, and searched reference lists of relevant reports to identify additional studies. We did not restrict studies with respect to language, date of publication, or study setting.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) comparing any type of internal dressing (packing) used in the post-operative management of perianal abscess cavities with alternative treatments or different types of internal dressing.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment, and data extraction.

MAIN RESULTS

We included two studies, with a total of 64 randomised participants (50 and 14 participants) aged 18 years or over, with a perianal abscess. In both studies, participants were enrolled on the first post-operative day and randomised to continued packing by community district nursing teams or to no packing. Participants in the non-packing group managed their own wounds in the community and used absorbant dressings to cover the area. Fortnightly follow-up was undertaken until the cavity closed and the skin re-epithelialised, which constituted healing. For non-attenders, telephone follow-up was conducted.Both studies were at high risk of bias due to risk of attrition, performance and detection bias.It was not possible to pool the two studies for the outcome of time to healing. It is unclear whether continued post-operative packing of the cavity of perianal abscesses affects time to complete healing. One study reported a mean time to wound healing of 26.8 days (95% confidence interval (CI) 22.7 to 30.7) in the packing group and 19.5 days (95% CI 13.6 to 25.4) in the non-packing group (it was not clear if all participants healed). We re-analysed the data and found no clear difference in the time to healing (7.30 days longer in the packing group, 95% CI -2.24 to 16.84; 14 participants). This was assessed as very low quality evidence (downgraded three levels for very serious imprecision and serious risk of bias). The second study reported a median time to complete wound healing of 24.5 days (range 10 to 150 days) in the packing group and 21 days (range 8 to 90 days) in the non-packed group. There was insufficient information to be able to recreate the analysis and the original analysis was inappropriate (did not account for censoring). This second study also provided very low quality evidence (downgraded four levels for serious risk of bias, serious indirectness and very serious imprecision).There was very low quality evidence (downgraded for risk of bias, indirectness and imprecision) of no difference in wound pain scores at the initial dressing change. Both studies also reported patients' retrospective judgement of wound pain over the preceding two weeks (visual analogue scale, VAS) as lower for the non-packed group (2; both studies) compared with the packed group (0; both studies); (very low quality evidence) but we have been unable to reproduce these analyses as no variance data were published.There was no clear evidence of a difference in the number of post-operative fistulae detected between the packed and non-packed groups (risk ratio (RR) 2.31, 95% CIs 0.56 to 9.45, I(2) = 0%) (very low quality evidence downgraded three levels for very serious imprecision and serious risk of bias).There was no clear evidence of a difference in the number of abscess recurrences between the packed and non-packed groups over the variable follow-up periods (RR 0.72, 95% CI 0.22 to 2.37, I(2) = 0%) (very low quality evidence downgraded three levels for serious risk of bias and very serious imprecision).No study reported participant health-related quality of life/health status, incontinence rates, time to return to work or normal function, resource use in terms of number of dressing changes or visits to a nurse, or change in wound size.

AUTHORS' CONCLUSIONS

It is unclear whether using internal dressings (packing) for the healing of perianal abscess cavities influences time to healing, wound pain, development of fistulae, abscess recurrence or other outcomes. Despite this absence of evidence, the practice of packing abscess cavities is commonplace. Given the lack of high quality evidence, decisions to pack may be based on local practices or patient preferences. Further clinical research is needed to assess the effects and patient experience of packing.

Do silver-based wound dressings reduce pain? A prospective study and review of the literature

Silver-containing dressings are a mainstay in the management of burn injury and acute and chronic wounds. In addition to antimicrobial activity, there is anecdotal evidence that silver dressings may modulate or reduce wound pain. Pain is subjective and difficult to quantify, and most studies of silver-containing dressings evaluate pain as a secondary rather than a primary outcome. Nevertheless, a dressing with a proven ability to reduce pain independent of systemic analgesics would have great utility. In this study, we compared patient-reported pain levels in patients previously randomized to receiving silver-nylon dressings vs. conventional gauze dressings in a study of surgical site infection. Compared to gauze dressings, patients in the silver dressing group reported less pain between postoperative days 0 and 9 (p<0.02). Post hoc analysis of analgesic use did not reach statistical significance between the groups. The study was completed with a literature review of the effect of silver on pain. Silver-based dressings may reduce wound pain by providing an occlusive barrier or by other as-yet undefined mechanisms. The role of silver in pain relief, however, cannot be definitively stated until well-designed prospective randomized studies evaluating pain as a primary endpoint are carried out.

A prospective, randomised study of a novel transforming methacrylate dressing compared with a silver-containing sodium carboxymethylcellulose dressing on partial-thickness skin graft donor sites in burn patients

This prospective, randomised study compares a new transforming methacrylate dressing (TMD) with a silver-containing carboxymethylcellulose dressing (CMC-Ag) after application to split-thickness skin graft (STSG) donor sites. This was an unblinded, non-inferiority, between-patient, comparison study that involved patients admitted to a single-centre burn unit who required two skin graft donor sites. Each patient's donor sites were covered immediately after surgery: one donor site with TMD and the other with CMC-Ag. The donor sites were evaluated until healing or until 24 days post-application, whichever came first. Study endpoints were time to healing, daily pain scores, number of dressing changes, patient comfort and physicians' and patients' willingness to use the dressings in the future. Nineteen patients had both the dressings applied. No statistically significant difference was noted in time to healing between the two dressings (14·2 days using TMD compared with 13·2 days using CMC-Ag). When pain scores were compared, TMD resulted in statistically significantly less pain at three different time periods (2-5 days, 6-10 days and 11-15 days; P < 0·001 at all time periods). Patients also reported greater comfort with TMD (P < 0·001). Users rated TMD as being less easy to use because of the time and technique required for application. Reductions in pain and increased patient comfort with the use of the TMD dressing, compared with CMC-Ag, were seen as clinical benefits as these are the major issues in donor site management.

Conservative Healing of an 11 × 9-cm Aplasia Cutis Congenita of the Scalp with Bone Defect

Objectives Aplasia cutis congenita is a rare congenital condition, and it is difficult to find scientific support for optimal treatment strategies. In addition, these may vary due to defect size, tissue layers involved, contemporary malformations, and the physiologic status of the affected child.

Clinical Presentation This case report describes complete skin coverage in 20 weeks and uneventful healing of a large 11 × 9-cm defect of the vertex, involving both skin and skull bone, using conservative treatment. To prevent infection and promote healing, the defect was kept moist and covered at all times, and it was treated with surgical debridement when necessary. For infection control, ionized silver-coated dressings were used in addition to prophylactic antibiotics over the first 3.5 weeks. Follow-up was 2 years.

Conclusion Surgical treatment is usually preferred for larger aplasia cutis congenita defects, but it is accompanied with potential risks and will exacerbate secondary reconstruction of alopecia or skull bone defects. This case shows that even very complex defects may be treated conservatively.

Update on management of skin and soft tissue infections in the emergency department

Skin and soft tissue infections (SSTIs) are frequently treated in the emergency department (ED) setting. Recent studies provide critical new information that can guide new approaches to the diagnosis and treatment of SSTIs in the ED. Rapid polymerase chain reaction assays capable of detecting MRSA in approximately 1 h hold significant potential to improving antibiotic stewardship in SSTI care. Emergency ultrasound continues to demonstrate value in guiding appropriate management of SSTIs, including the early diagnosis of necrotizing infections. Since emerging in the 1990s, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) continues to increase in prevalence, and it represents a significant challenge to optimizing ED antibiotic use for SSTI management. Growing literature reinforces the current recommendation of incision and drainage without antibiotics for uncomplicated abscesses. Selecting antibiotics with CA-MRSA coverage is recommended when treating purulent SSTIs; however, it is generally not necessary in cases of nonpurulent cellulitis. Future advances in ED SSTI care may involve expansion of outpatient parenteral antimicrobial therapy protocols and the recent development of a novel, once weekly antibiotic with activity against MRSA.