Contemporary causes of skin and soft tissue infections in North America, Latin America, and Europe: Report from the SENTRY Antimicrobial Surveillance Program (1998–2004)

Epidemiology, treatment, and economics of patients presenting to the emergency department for skin and soft tissue infections

OBJECTIVES

Skin and soft tissue infections (SSTIs) are among the most common bacterial diseases and represent a significant disease burden. The purpose of this study was to describe the real-world management of patients with SSTIs presenting to the emergency department (ED).

METHODS

This is a retrospective cohort study. Adult patients identified with a primary diagnosis of SSTI determined by ICD-9 codes were assessed from index presentation for up to 30 days. Records were reviewed 30 days prior to inclusion to ensure index hospitalization was captured. For recurrent visits, a similar strategy was implemented 30 days afterward.

RESULTS

Of 446 encounters screened, 357 were included; 106 (29.7%) were admitted to the hospital and 251 (70.3%) were treated outpatient. Of patients with a Charlson Comorbidity Index (CCI) score two or greater, 60.9% were treated as inpatients, whereas admission rates were 30.1% and 14.1% for patients with a CCI score of one and zero, respectively. Inpatients had an average length of stay (LOS) of 7.3 ± 7.1 days. No difference was detected in overall re-presentation to the facility 22.6% and 28.3% (p > 0.05) or in SSTI related re-presentation 10.4% and 15.1% (p > 0.05) between inpatient and outpatients. The most common gram-positive organisms identified on wound/abscess culture were MSSA (37.1% inpatients) and MRSA (66.7% outpatients). Mean total cost of care was $13,313 for inpatients and $413 for outpatients.

CONCLUSION

This analysis identifies opportunities to improve processes of care for SSTIs with the aim of decreasing LOS, reducing readmissions, and ultimately decreasing burden on the healthcare system.

Effect of Negative Pressure on Proliferation, Virulence Factor Secretion, Biofilm Formation, and Virulence-Regulated Gene Expression of Pseudomonas aeruginosa In Vitro

Objective. To investigate the effect of negative pressure conditions induced by NPWT on P. aeruginosa. Methods. P. aeruginosa was cultured in a Luria-Bertani medium at negative pressure of -125 mmHg for 24 h in the experimental group and at atmospheric pressure in the control group. The diameters of the colonies of P. aeruginosa were measured after 24 h. ELISA kit, orcinol method, and elastin-Congo red assay were used to quantify the virulence factors. Biofilm formation was observed by staining with Alexa Fluor® 647 conjugate of concanavalin A (Con A). Virulence-regulated genes were determined by quantitative RT-PCR. Results. As compared with the control group, growth of P. aeruginosa was inhibited by negative pressure. The colony size under negative pressure was significantly smaller in the experimental group than that in the controls (p < 0.01). Besides, reductions in the total amount of virulence factors were observed in the negative pressure group, including exotoxin A, rhamnolipid, and elastase. RT-PCR results revealed a significant inhibition in the expression level of virulence-regulated genes. Conclusion. Negative pressure could significantly inhibit the growth of P. aeruginosa. It led to a decrease in the virulence factor secretion, biofilm formation, and a reduction in the expression level of virulence-regulated genes.

A Phase III, randomized, controlled, non-inferiority trial of ceftaroline fosamil 600 mg every 8 h versus vancomycin plus aztreonam in patients with complicated skin and soft tissue infection with systemic inflammatory response or underlying comorbidities

OBJECTIVES

Increasing the ceftaroline fosamil dose beyond 600 mg every 12 h may provide additional benefit for patients with complicated skin and soft tissue infections (cSSTIs) with severe inflammation and/or reduced pathogen susceptibility. A Phase III multicentre, randomized trial evaluated the safety and efficacy of ceftaroline fosamil 600 mg every 8 h in this setting.

METHODS

Adult patients with cSSTI and systemic inflammation or comorbidities were randomized 2:1 to intravenous ceftaroline fosamil (600 mg every 8 h) or vancomycin (15 mg/kg every 12 h) plus aztreonam (1 g every 8 h) for 5-14 days. Clinical cure was assessed at the test of cure (TOC) visit (8-15 days after the final dose) in the modified ITT (MITT) and clinically evaluable (CE) populations. Non-inferiority was defined as a lower limit of the 95% CI around the treatment difference greater than -10%. An MRSA-focused expansion period was initiated after completion of the main study. Clinicaltrials.gov registration numbers NCT01499277 and NCT02202135.

RESULTS

Clinical cure rates at TOC demonstrated non-inferiority of ceftaroline fosamil 600 mg every 8 h versus vancomycin plus aztreonam in the MITT and CE populations: 396/506 (78.3%) versus 202/255 (79.2%) patients (difference -1.0%, 95% CI -6.9, 5.4) and 342/395 (86.6%) versus 180/211 (85.3%) patients (difference 1.3%, 95% CI -4.3, 7.5), respectively. In the expansion period, 3/4 (75%) patients treated with ceftaroline fosamil were cured at TOC. The frequency of adverse events was similar between groups.

CONCLUSIONS

Ceftaroline fosamil 600 mg every 8 h was effective for cSSTI patients with evidence of systemic inflammation and/or comorbidities. No new safety signals were identified.

National Athletic Trainers' Association Position Statement: Management of Acute Skin Trauma

OBJECTIVE

  To present recommendations for the cleansing, debridement, dressing, and monitoring of acute skin trauma in patients.

BACKGROUND

  Acute skin trauma is common during participation in athletic and recreational activities. Clinical decisions and intervention protocols after injury vary among athletic trainers and are often based on ritualistic practices. An understanding of cleansing, debridement, and dressing techniques; clinical features of infection and adverse reactions; and monitoring of acute skin trauma is critical for certified athletic trainers and other allied health and medical professionals to create a local wound environment that promotes healing and lessens the risk of complications.

RECOMMENDATIONS

  These guidelines are intended to provide the certified athletic trainer and others participating in athletic health care with specific knowledge about and recommendations for the management of acute skin trauma.

Topical simvastatin promotes healing of Staphylococcus aureus-contaminated cutaneous wounds

Cutaneous wounds are prompt to be contaminated by bacteria, but the clinical benefits of applying antibiotics and antiseptics in wound management have not been proven. Statins are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors commonly used to lower cholesterol levels. Studies indicated that statins, especially simvastatin, promote wound healing in experimental models. As Staphylococcus aureus is one of the most important microorganism responsible for wound infections, the aims of this study were to characterise the anti-staphylococcal activity of simvastatin and to evaluate the application of simvastatin as a topical therapy for S. aureus-contaminated wounds. In the present study, simvastatin was bacteriostatic against S. aureus at sub-inhibitory concentrations up to 8 hours after exposure. Further increased concentrations of simvastatin above the minimal inhibitory concentration (MIC) did not enhance the growth inhibitory effect. By contrast, the ability of simvastatin to inhibit S. aureus biofilm formation was concentration dependent. Topical application of simvastatin at its MIC against S. aureus accelerated the healing and bacterial clearance of S. aureus-contaminated wounds in an excisional mice wound model. This effective concentration is well below the safe concentration for topical use. Collectively, topical application of simvastatin has the potential as a novel modality for managing wound infections and promoting wound healing.

Diagnosis and management of skin and soft tissue infections in the intensive care unit: a review

PURPOSE

To review the salient features of the diagnosis and management of the most common skin and soft tissue infections (SSTI). This review focuses on severe SSTIs that require care in an intensive care unit (ICU), including toxic shock syndrome, myonecrosis/gas gangrene, and necrotizing fasciitis.

METHODS

Guidelines, expert opinion, and local institutional policies were reviewed.

RESULTS

Severe SSTIs are common and their management complex due to regional variation in predominant pathogens and antimicrobial resistance patterns, as well as variations in host immune responses. Unique aspects of care for SSTIs in the ICU are discussed, including the role of prosthetic devices, risk factors for bacteremia, and the need for surgical consultation. SSTI mimetics, the role of dermatologic consultation, and the unique features of SSTIs in immunocompromised hosts are also described.

CONCLUSIONS

We provide recommendations for clinicians regarding optimal SSTI management in the ICU setting.

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.

Low sensitivity of needle aspiration cultures in patients with cellulitis/erysipelas

Purpose

Cellulitis is normally treated without knowledge of the responsible pathogen. Blood cultures are positive in about 2–4 %, and superficial swabs are of no value. Needle aspiration has been proposed with identifying the likely pathogen in up to 29 %, but these studies are of older date and the technique is not widely used.

Methods

We prospectively evaluated the sensitivity of needle aspiration cultures in all patients with erysipelas/cellulitis. Diagnosis was made clinically by the treating physician. Needle aspiration was done with a 1 ml syringe and a 26G needle. The needle was removed and the syringe brought to the microbiological laboratory and analysed according to standard procedures.

Results

95 Patients were seen during a period of 22 month. 4 Patients were excluded, as diagnosis was not confirmed. Cellulitis was present in 10/91 and erysipelas in 81/91 patients. In the first 25 patients with needle aspiration from the margin, none was positive. In 8/66 (12 %) patients where needle aspiration was done at the site of maximum inflammation, the pathogen was identified. 4/8 Cultures were positive for S. aureus, 2/8 for streptococci and 2/8 for other bacteria. In 11/66 (16.6 %) patients, skin colonisation flora was detected. In the subgroup of patients without prior antibiotic treatment and needle aspiration from the site of maximum inflammation, sensitivity was slightly better 8/55 (14.5 %; 95 % CI 7.5–25.8 %).

Conclusions

Needle aspiration culture had a low sensitivity for detecting responsible pathogen in patients with cellulitis/erysipelas. No impact in antibiotic treatment could be observed.

Acute bacterial skin and skin structure infections in internal medicine wards: old and new drugs

Skin and soft tissue infections (SSTIs) are a common cause of hospital admission among elderly patients, and traditionally have been divided into complicated and uncomplicated SSTIs. In 2010, the FDA provided a new classification of these infections, and a new category of disease, named acute bacterial skin and skin structure infections (ABSSSIs), has been proposed as an independent clinical entity. ABSSSIs include three entities: cellulitis and erysipelas, wound infections, and major cutaneous abscesses This paper revises the epidemiology of SSTIs and ABSSSIs with regard to etiologies, diagnostic techniques, and clinical presentation in the hospital settings. Particular attention is owed to frail patients with multiple comorbidities and underlying significant disease states, hospitalized on internal medicine wards or residing in nursing homes, who appear to be at increased risk of infection due to multi-drug resistant pathogens and treatment failures. Management of ABSSSIs and SSTIs, including evaluation of the hemodynamic state, surgical intervention and treatment with appropriate antibiotic therapy are extensively discussed.

Regulatory Requirements for Staphylococcus aureus Nitric Oxide Resistance

The ability of Staphylococcus aureus to resist host innate immunity augments the severity and pervasiveness of its pathogenesis. Nitric oxide (NO˙) is an innate immune radical that is critical for the efficient clearance of a wide range of microbial pathogens. Exposure of microbes to NO˙ typically results in growth inhibition and induction of stress regulons. S. aureus, however, induces a metabolic state in response to NO˙ that allows for continued replication and precludes stress regulon induction. The regulatory factors mediating this distinctive response remain largely undefined. Here, we employ a targeted transposon screen and transcriptomics to identify and characterize five regulons essential for NO˙ resistance in S. aureus: three virulence regulons not formerly associated with NO˙ resistance, SarA, CodY, and Rot, as well as two regulons with established roles, Fur and SrrAB. We provide new insights into the contributions of Fur and SrrAB during NO˙ stress and show that the S. aureus ΔsarA mutant, the most sensitive of the newly identified mutants, exhibits metabolic dysfunction and widespread transcriptional dysregulation following NO˙ exposure. Altogether, our results broadly characterize the regulatory requirements for NO˙ resistance in S. aureus and suggest an intriguing overlap between the regulation of NO˙ resistance and virulence in this well-adapted human pathogen.

IMPORTANCE

The prolific human pathogen Staphylococcus aureus is uniquely capable of resisting the antimicrobial radical nitric oxide (NO˙), a crucial component of the innate immune response. However, a complete understanding of how S. aureus regulates an effective response to NO˙ is lacking. Here, we implicate three central virulence regulators, SarA, CodY, and Rot, as major players in the S. aureus NO˙ response. Additionally, we elaborate on the contribution of two regulators, SrrAB and Fur, already known to play a crucial role in S. aureus NO˙ resistance. Our study sheds light on a unique facet of S. aureus pathogenicity and demonstrates that the transcriptional response of S. aureus to NO˙ is highly pleiotropic and intrinsically tied to metabolism and virulence regulation.

Anti-infective efficacy of the lactoferrin-derived antimicrobial peptide HLR1r

Antimicrobial peptides (AMPs) have emerged as a new class of drug candidates for the treatment of infectious diseases. Here we describe a novel AMP, HLR1r, which is structurally derived from the human milk protein lactoferrin and demonstrates a broad spectrum microbicidal action in vitro. The minimum concentration of HLR1r needed for killing ≥99% of microorganisms in vitro, was in the range of 3-50μg/ml for common Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), and for the yeast Candida albicans, when assessed in diluted brain-heart infusion medium. We found that HLR1r also possesses anti-inflammatory properties as evidenced by inhibition of tumor necrosis factor alpha (TNF-α) secretion from human monocyte-derived macrophages and by repression of interleukin-6 (IL-6) and plasminogen activator inhibitor-1 (PAI-1) secretion from human mesothelial cells, without any cytotoxic effect observed at the concentration range tested (up to 400μg/ml). HLR1r demonstrated pronounced anti-infectious effect in in vivo experimental models of cutaneous candidiasis in mice and of excision wounds infected with MRSA in rats as well as in an ex vivo model of pig skin infected with S. aureus. In conclusion, HLR1r may constitute a new therapeutic alternative for local treatment of skin infections.

Efficacy of Lantibiotic Treatment of Staphylococcus aureus-Induced Skin Infections, Monitored by In Vivo Bioluminescent Imaging

Staphylococcus aureus is a bacterial pathogen responsible for the majority of skin and soft tissue infections. Antibiotics are losing their efficacy as treatment for skin and soft tissue infections as a result of increased resistance in a variety of pathogens, including S. aureus It is thus imperative to explore alternative antimicrobial treatments to ensure future treatment options for skin and soft tissue infections. A select few lantibiotics, a group of natural defense peptides produced by bacteria, inhibit the growth of numerous clinical S. aureus isolates, including methicillin-resistant strains. In this study, the antimicrobial activities of nisin, clausin, and amyloliquecidin, separately administered, were compared to that of a mupirocin-based ointment, which is commonly used as treatment for S. aureus-induced skin infections. Full-thickness excisional wounds, generated on the dorsal surfaces of mice, were infected with a bioluminescent strain of S. aureus (strain Xen 36). The infections were monitored in real time using in vivo bioluminescent imaging. Lantibiotic treatments significantly reduced the bioluminescence of S. aureus Xen 36 to a level similar to that recorded with mupirocin treatment. Wound closure, however, was more pronounced during lantibiotic treatment. Lantibiotics thus have the potential to be used as an alternative treatment option for S. aureus-induced skin infections.

The effect of an emollient with benfothiamine and Biolin prebiotic on the improvement of epidermal skin function

INTRODUCTION

Complications of diabetes can damage internal organs and the skin. Diabetic skin, irritated and dry, is susceptible to skin infections. However little is known about influence of emollients on biophysical changes in skin during diabetes.

AIM

To evaluate clinical skin changes after application of emollients with benfothiamine and Biolin prebiotic and to assess changes in biophysical parameters of the skin before and 4 weeks after daily application of an emollient.

MATERIAL AND METHODS

We recruited 50 patients with diabetes mellitus type 1 (DM1) or type 2 (DM2). All participants applied emollients on their left forearms and left shins for 4 weeks. The biophysical properties: pH, transepidermal water loss (TEWL), hydration of the stratum corneum and sebum content were measured and compared to those before enrollment to the study, after 1 h, 1 week and 4 weeks after application of an emollient.

RESULTS

After 4 weeks of treatment, there was an increase in skin hydration (40.61 ±19.03 vs. 48.83 ±15.51), pH (5.11 ±0.56 to 5.27 ±0.48) and sebum content (22.16 ±8.67 to 63.99 ±25.41) and a decrease in TEWL (12.54 ±5.6 vs. 9.85 ±5.69 g/m(2)/h) on forearms (p < 0.05 for all comparisons). On lower legs, significant changes in skin hydration (37.21 ±14.01 vs. 43.95 ±12.67), pH (5.04 ±0.57 to 5.31 ±0.49), sebum content (25.82 ±10.46 to 72.63 ±31.23) and TEWL (8.87 ±4.05 vs. 7.39 ±3.22 g/m(2)/h) were observed (p < 0.05 for all comparisons).

CONCLUSIONS

Our study provides an insight into changes in diabetic skin after application of an emollient. To our knowledge, this is the first report on the emollient containing benfothiamine and Biolin prebiotic and its influence on biophysical parameters of epidermis.

Skin and soft-tissue infections: a critical review and the role of telavancin in their treatment

Skin and soft-tissue infections (SSTIs) are an important cause of morbidity and mortality among hospitalized patients and a major therapeutic challenge for clinicians. Although uncomplicated SSTIs are managed successfully on an outpatient basis, more serious infections extending to the subcutaneous tissue, fascia, or muscle require complex management. Early diagnosis, selection of appropriate antimicrobials, and timely surgical intervention are key to successful treatment. Surgical-site infections, an important category of SSTI, occur in approximately half a million patients in North America annually. SSTIs are also a potential source for life-threatening bacteremia and metastatic abscesses. Gram-positive organisms, such as Staphylococcus aureus and Streptococcus pyogenes, are the dominant organisms isolated early in the infectious process, whereas gram-negative organisms are found in chronic wounds. Methicillin-resistant S. aureus (MRSA) is a potential bloodstream invader that requires aggressive antimicrobial treatment and surgery. Recent concerns regarding vancomycin activity include heteroresistance in MRSA and increase in the minimum inhibitory concentrations (>1 or 2 µg/mL); however, alternative agents, such as telavancin, daptomycin, linezolid, ceftaroline, dalbavancin, oritavancin, and tedizolid, are now available for the treatment of severe MRSA infections. Here, we present a review of the epidemiology, etiology, and available treatment options for the management of SSTIs.

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.

Examination of hospital length of stay in Canada among patients with acute bacterial skin and skin structure infection caused by methicillin-resistant Staphylococcus aureus

PURPOSE

Skin infections, particularly those caused by resistant pathogens, represent a clinical burden. Hospitalization associated with acute bacterial skin and skin structure infections (ABSSSI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is a major contributor to the economic burden of the disease. This study was conducted to provide current, real-world data on hospitalization patterns for patients with ABSSSI caused by MRSA across multiple geographic regions in Canada.

PATIENTS AND METHODS

This retrospective cohort study evaluated length of stay (LOS) for hospitalized patients with ABSSSI due to MRSA diagnosis across four Canadian geographic regions using the Discharge Abstract Database. Patients with ICD-10-CA diagnosis consistent with ABSSSI caused by MRSA between January 2008 and December 2014 were selected and assigned a primary or secondary diagnosis based on a prespecified ICD-10-CA code algorithm.

RESULTS

Among 6,719 patients, 3,273 (48.7%) and 3,446 (51.3%) had a primary and secondary diagnosis, respectively. Among patients with a primary or secondary diagnosis, the cellulitis/erysipelas subtype was most common. The majority of patients presented with 0 or 1 comorbid condition; the most common comorbidity was diabetes. The mean LOS over the study period varied by geographic region and year; in 2014 (the most recent year analyzed), LOS ranged from 7.7 days in Ontario to 13.4 days in the Canadian Prairie for a primary diagnosis and from 18.2 days in Ontario to 25.2 days in Atlantic Canada for a secondary diagnosis. A secondary diagnosis was associated with higher rates of continuing care compared with a primary diagnosis (10.6%-24.2% vs 4.6%-12.1%).

CONCLUSION

This study demonstrated that the mean LOS associated with ABSSSI due to MRSA in Canada was minimally 7 days. Clinical management strategies, including medication management, which might facilitate hospital discharge, have the potential to reduce hospital LOS and related economic burden associated with ABSSSI caused by MRSA.

Multicenter Evaluation of MRSASelect II Chromogenic Agar for Identification of Methicillin-Resistant Staphylococcus aureus from Wound and Nasal Specimens

Hospitals strive to reduce methicillin-resistant Staphylococcus aureus (MRSA) prevalence via active surveillance of inpatient populations. Rapid and inexpensive screening methods are utilized when molecular methods are not operationally feasible. In this multisite clinical trial, the utility of Bio-Rad's MRSASelect II was evaluated for MRSA identification from remnant nares and wound swabs. The prevalence of MRSA was 11.1% (n = 1,384) from nares samples and 18.1% (n = 842) from wound samples. MRSASelect II had an overall concordance of 95.4% (confidence interval [CI] = 94.5% to 96.2%) compared to a broth-enriched reference standard. Comparisons between results, stratified by examination times, exhibited a nonsignificant trend toward increased positivity at prolonged incubation times. Cefoxitin screening of colonies directly from MRSASelect II was 96.7% (95.8% to 97.3%) concordant compared to testing of colonies following broth enrichment. A comparison of MRSASelect and MRSASelect II revealed no statistical differences; however, the latter exhibited earlier positivity, greater selectivity, and more intense indicator staining, which resulted in facilitated differentiation of positive results. MRSASelect II agar is a simple, rapid, and robust method to routinely screen patients for MRSA colonization without the need for additional testing.

Early application of negative pressure wound therapy to acute wounds contaminated with Staphylococcus aureus: An effective approach to preventing biofilm formation

Negative pressure wound therapy (NPWT) has been demonstrated to be effective at preventing biofilm-associated infections; however, its role in biofilm prevention is unknown. The present study evaluated the effect of NPWT on biofilm prevention when rapidly initiated following wound contamination. Full-thickness dermal wounds (8 mm) were created in rabbit ears and inoculated with green fluorescent protein-labeled Staphylococcus aureus (S. aureus). At 6 h following inoculation, continuous NPWT at -125 mmHg was initiated, with the wounds on the contralateral ear left untreated in order to serve as self-controls. S. aureus rapidly formed mature biofilms in the wound beds post-inoculation, with a persistent bacterial burden of ~10⁵-10⁷ colony-forming units (CFUs)/wound and impaired wound healing. Compared with the untreated group, NPWT resulted in a significant reduction in biofilm matrix, which was verified by scanning electron microscopy and epifluorescence. A reduction in bacterial counts followed (P<0.05) with ~10³ CFUs/wound on postoperative day 13 and improvement in all healing parameters (P<0.05) relative to control wounds. The results of the present investigation suggest that NPWT is an effective strategy to impeding the formation of S. aureus wound biofilms when initiated rapidly following bacterial contamination. The early application of NPWT, aimed at biofilm prevention, may improve wound care.

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.

Staphylococcus aureus-Associated Skin and Soft Tissue Infections: Anatomical Localization, Epidemiology, Therapy and Potential Prophylaxis

Skin and soft tissue infections (SSTIs) are among the most common infections worldwide. They range in severity from minor, self-limiting, superficial infections to life-threatening diseases requiring all the resources of modern medicine. Community (CA) and healthcare (HA) acquired SSTIs are most commonly caused by Staphylococcus aureus . They have variable presentations ranging from impetigo and folliculitis to surgical site infections (SSIs). Superficial SSTIs may lead to even more invasive infections such as bacteraemia and osteomyelitis. Here we describe the anatomical localization of the different SSTI associated with S. aureus, the virulence factors known to play a role in these infections, and their current epidemiology. Current prevention and treatment strategies are also discussed. Global epidemiological data show increasing incidence and severity of SSTIs in association with methicillin-resistant S. aureus strains (MRSA). CA-SSTIs are usually less morbid compared to other invasive infections caused by S. aureus, but they have become the most prevalent, requiring a great number of medical interventions, extensive antibiotic use, and therefore a high cost burden. Recurrence of SSTIs is common after initial successful treatment, and decolonization strategies have not been effective in reducing recurrence. Furthermore, decolonization approaches may be contributing to the selection and maintenance of multi-drug resistant strains. Clinical studies from the early 1900s and novel autovaccination approaches suggest an alternative strategy with potential effectiveness: using vaccines to control S. aureus cutaneous infections.

Vaccines for Staphylococcus aureus and Target Populations

Staphylococcus aureus is a leading pathogen in surgical site, intensive care unit, and skin infections, as well as healthcare-associated pneumonias. These infections are associated with an enormous burden of morbidity, mortality, and increase of hospital length of stay and patient cost. S. aureus is impressively fast in acquiring antibiotic resistance, and multidrug-resistant strains are a serious threat to human health. Due to resistance or insufficient effectiveness, antibiotics and bundle measures leave a tremendous unmet medical need worldwide. There are no licensed vaccines on the market despite the significant efforts done by public and private initiatives. Indeed, vaccines tested in clinical trials in the last two decades have failed to show efficacy. However, they targeted single antigens and contained no adjuvants and efficacy trials were performed in severely ill subjects. Herein, we provide a comprehensive evaluation of potential target populations for efficacy trials taking into account key factors such as population size, incidence of S. aureus infection, disease outcome, primary endpoints, as well as practical advantages and disadvantages. We describe the whole-blood assay as a potential surrogate of protection, and we show the link between phase III clinical trial data of failed vaccines with their preclinical observations. Finally, we give our perspective on how new vaccine formulations and clinical development approaches may lead to successful S. aureus vaccines.

Managing skin and soft-tissue infection and nosocomial pneumonia caused by MRSA: a 2014 follow-up survey

As a follow-up to our 2009 survey, in order to explore opinion and practice on the epidemiology and management of meticillin-resistant Staphylococcus aureus (MRSA) in Europe, we conducted a second survey to elicit current opinions on this topic, particularly around antibiotic choice, dose, duration and route of administration. We also aimed to further understand how the management of MRSA has evolved in Europe during the past 5 years. Members of an expert panel of infectious diseases specialists convened in London (UK) in January 2014 to identify and discuss key issues in the management of MRSA. Following this meeting, a survey was developed comprising 36 questions covering a wide range of topics on MRSA complicated skin and soft-tissue infection and nosocomial pneumonia management. The survey instrument, a web-based questionnaire, was sent to the International Society of Chemotherapy for distribution to registered European infection societies and their members. This article reports the survey results from the European respondents. At the time of the original survey, the epidemiology of MRSA varied significantly across Europe and there were differing views on best practice. The current findings suggest that the epidemiology of healthcare-associated MRSA in Europe is, if anything, even more polarised, whilst community-acquired MRSA has become much more common. However, there now appears to be a much greater knowledge of current treatment/management options, and antimicrobial stewardship has moved forward considerably in the 5 years since the last survey.

In Vitro Activity of Ceftaroline against Staphylococcus aureus Isolates Collected in 2012 from Latin American Countries as Part of the AWARE Surveillance Program

The in vitro activities of ceftaroline and comparators, using broth microdilution, were determined against 1,066 Staphylococcus aureus isolates from hospitalized patients. Seventeen medical centers from Latin American countries contributed isolates. Methicillin-resistant S. aureus (MRSA) percentages ranged from 46% (Brazil) to 62% (Argentina). All methicillin-susceptible S. aureus (MSSA) isolates were susceptible to ceftaroline. Ceftaroline activity against MRSA varied with MIC90s of 0.5 (Venezuela) to 2 (Brazil, Chile, and Colombia) μg/ml, which was the highest MIC value. ST-5 was the most common sequence type.

Blood Cultures Are Not Useful in the Evaluation of Children with Uncomplicated Superficial Skin and Soft Tissue Infections

BACKGROUND

Blood cultures (BCs) are commonly performed on children admitted to hospital for skin and soft tissue infections (SSTIs). In recent years, this practice has been questioned in patients with uncomplicated SSTIs because of its low yield. At the same time, however, an increase in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections has been described; its influence on rates of bacteremia in patients with SSTIs is unclear. The aims of the study were to describe the performance and the yield of BC in immunocompetent patients with uncomplicated SSTIs and to determine the prevalence of CA-MRSA as a causative agent in our area.

METHODS

Retrospective study: immunocompetent patients younger than 18 years evaluated in the emergency department and admitted for uncomplicated SSTIs (cellulitis, abscess, impetigo or erysipelas) from July 1, 2010 to June 31, 2014 were included. Patients referred from other hospitals who were receiving parenteral antibiotics and patients with complicated SSTIs (surgical or traumatic wound infection, need for surgical intervention and infected ulcers or burns) were excluded.

RESULTS

We included 445 cases: 348 (78.2%) cellulitis, 78 (17.5%) abscess and 19 (4.3%) impetigo. BCs were performed on 353 (79.3%) patients. Two (0.6%; 95% confidence interval: 0.2-2.0%) were positive and 10 (2.8%; 95% confidence interval: 1.5-5.1%) contaminated. The positive BCs grew S. aureus and Streptococcus pyogenes. Wound cultures were performed on 148 (33.3%) patients; 98 (66.2%) were positive. In 22 (22.4%) patients CA-MRSA grew, accounting for 14.9% of overall wound cultures.

CONCLUSIONS

BCs are not useful in the management of immunocompetent patients admitted to the hospital with uncomplicated SSTIs. The prevalence of CA-MRSA is low in our area, but continuing careful surveillance is needed.

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.

Antibiotic Susceptibility of Staphylococcus aureus in Atopic Dermatitis: Current Prevalence of Methicillin-Resistant Staphylococcus aureus in Korea and Treatment Strategies

BACKGROUND

Staphylococcus aureus is a well-known microbe that colonizes or infects the skin in atopic dermatitis (AD). The prevalence of methicillin-resistant S. aureus (MRSA) in AD has recently been increasing.

OBJECTIVE

This study aimed to determine the antimicrobial susceptibility patterns in AD skin lesions and evaluate the prevalence of MRSA in Korea. We also recommend proper first-line topical antibiotics for Korean patients with AD.

METHODS

We studied S. aureus-positive skin swabs (n=583) from the lesional skin of infants, children, and adults who presented to our outpatient clinic with AD from July 2009 to April 2012.

RESULTS

S. aureus exhibited high susceptibility against most antimicrobial agents. However, it exhibited less susceptibility to benzylpenicillin, erythromycin, clindamycin, and fusidic acid. The prevalence of MRSA was 12.9% among 583 S. aureus isolates, and the susceptibility to oxacillin was significantly lower in infants in both acute and chronic AD lesions.

CONCLUSION

S. aureus from AD has a high prevalence of MRSA and multidrug resistance, especially in infants. In addition, the rate of fusidic acid resistance is high among all age groups, and mupirocin resistance increases with age group regardless of lesional status. This is the first study comparing the antimicrobial susceptibility rates of S. aureus isolates from AD cases with respect to age and lesion status in Korea.

Antimicrobial Susceptibility Profiles of Staphylococcus aureus Isolates Recovered from Humans, Environmental Surfaces, and Companion Animals in Households of Children with Community-Onset Methicillin-Resistant S. aureus Infections

Our objective was to determine the antibiotic susceptibility profiles of Staphylococcus aureus isolates recovered from 110 households of children with community-onset methicillin-resistant S. aureus (MRSA) infections. Cultures were obtained from household members, household objects, and dogs and cats, yielding 1,633 S. aureus isolates. The S. aureus isolates were heterogeneous, although more than half were methicillin resistant. The highest proportion of MRSA was found in bathrooms. The majority of isolates were susceptible to antibiotics prescribed in outpatient settings.

Pathophysiology and burden of infection in patients with diabetes mellitus and peripheral vascular disease: focus on skin and soft-tissue infections

Diabetes mellitus affects 284 million adults worldwide and is increasing in prevalence. Accelerated atherosclerosis in patients with diabetes mellitus contributes an increased risk of developing cardiovascular diseases including peripheral vascular disease (PVD). Immune dysfunction, diabetic neuropathy and poor circulation in patients with diabetes mellitus, especially those with PVD, place these patients at high risk for many types of typical and atypical infections. Complicated skin and soft-tissue infections (cSSTIs) are of particular concern because skin breakdown in patients with advanced diabetes mellitus and PVD provides a portal of entry for bacteria. Patients with diabetes mellitus are more likely to be hospitalized with cSSTIs and to experience related complications than patients without diabetes mellitus. Patients with PVD requiring lower extremity bypass are also at high risk of surgical site and graft infections. Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent causative pathogen in cSSTIs, and may be a significant contributor to surgical site infections, especially in patients who are colonized with MRSA on hospital admission. Patients with cSSTIs and diabetes mellitus or PVD experience lower clinical success rates than patients without these comorbidities, and may also have a longer length of hospital stay and higher risk of adverse drug events. Clinicians should be vigilant in recognizing the potential for infection with multi-drug-resistant organisms, especially MRSA, in these populations and initiating therapy with appropriate antibiotics.

Direct molecular versus culture-based assessment of Gram-positive cocci in biopsies of patients with major abscesses and diabetic foot infections

Major abscesses and diabetic foot infections (DFIs) are predominant subtypes of complicated skin and skin structure infections (cSSSIs), and are mainly caused by Staphylococcus aureus and β-hemolytic streptococci. This study evaluates the potential benefit of direct pathogen-specific real-time polymerase chain reaction (PCR) assays in the identification of causative organisms of cSSSIs. One-hundred and fifty major abscess and 128 DFI biopsy samples were collected and microbial DNA was extracted by using the Universal Microbe Detection kit for tissue samples. Pathogen-specific PCRs were developed for S. aureus and its virulence factor Panton–Valentine leukocidin (PVL), Streptococcus pyogenes, S. agalactiae, S. dysgalactiae, and the S. anginosus group. Identification by pathogen-specific PCRs was compared to routine culture and both methods were considered as the gold standard for determination of the sensitivity and specificity of each assay. Direct real-time PCR assays of biopsy samples resulted in a 34 % higher detection of S. aureus, 37 % higher detection of S. pyogenes, 18 % higher detection of S. agalactiae, 4 % higher detection of S. dysgalactiae subspecies equisimilis, and 7 % higher detection of the S. anginosus group, compared to routine bacterial culture. The presence of PVL was mainly confined to S. aureus isolated from major abscess but not DFI biopsy samples. In conclusion, our pathogen-specific real-time PCR assays had a higher yield than culture methods and could be an additional method for the detection of relevant causative pathogens in biopsies.

Tigecycline in the Treatment of Patients with Necrotizing Skin and Soft Tissue Infections Due to Multiresistant Bacteria

BACKGROUND

Necrotizing skin and soft tissue infections (NSTI) form a group of aggressive diseases that require radical debridement for infection control. Simultaneously, a high-dose broad spectrum antibiotic regimen needs to be initiated with control of septic complications in the intensive care setting. The aim of this work is to analyze the efficacy and safety of tigecycline in a subpopulation of hospitalized, severely ill surgical NSTI patients who were documented in a large multicenter non-interventional study on tigecycline use in routine clinical practice.

METHODS

A total of 1,025 patients with severe infections including complicated skin and soft-tissue infections (cSSTI, n=163; 15,9%) were enrolled in a prospective multi-center non-interventional study. Patients were to receive an initial intravenous dose of 100 mg tigecycline, followed by 50 mg twice daily. Prospectively documented parameters included clinical findings, APACHE II score, microbiological and standard laboratory assessments, surgical measures, and clinical outcomes including adverse events.

RESULTS

Of 163 patients were treated for cSSTI, with the largest subgroup being NSTI patients (n=50, 30.7% of all cSSTI, mean age 61 y, median APACHE II score 20). Forty-eight NSTI patients (96%) had at least one comorbidity. In 80% of patients, the treatment was started after previous antibiotic treatment had failed and in 34% resistant pathogens were isolated (28% methicillin resistant Staphyloccocus aureus [MRSA], 4% extended-spectrum-beta-lactamase (ESBL)-producing bacteria, and 2% vancomycin-resistant Enterococci (VRE). Tigecycline was administered as a single agent in 32 patients; 17 received combination regimens. Data from one patient were not reported. Rates of clinical cure or improvement with tigecycline treatment were 90.2%. Two patients (4%) had drug related adverse events (one thrombocytopenia and one fever/chills); 10 patients (20%) died.

CONCLUSIONS

Tigecycline alone or in combination therapy was an effective and safe antibiotic treatment in critically ill and antimicrobially pre-treated patients with NSTI frequently caused by resistant pathogens.

Distribution and antimicrobial susceptibility of bacteria from adults with community-acquired pneumonia or complicated skin and soft tissue infections in France: the nationwide French PREMIUM study

The empirical therapy of community-acquired pneumonia (CAP) and complicated skin and soft tissue infections (cSSTIs) must be based on updated bacterial distribution and susceptibility data. A nationwide study consecutively collected 1288 isolates from CAP (n=467) and cSSTIs (n=821) from 18 French hospitals between 2012 and 2013. The MIC values of commonly used antimicrobial agents, including ceftaroline, were determined. Bacterial distribution featured Pneumococcus, Haemophilus influenzae, and Staphylococcus aureus for CAPs and S. aureus, β-hemolytic streptococci and Enterobacteriaceae for cSSTIs. Antimicrobial susceptibility testing indicated i) the sustained third-generation cephalosporins and levofloxacin activity against pneumococci and H. influenzae, ii) no methicillin-resistant Staphylococcus aureus emergence among respiratory pathogens, iii) the high in vitro activity of ceftaroline against staphylococci from cSSTIs (98.7% susceptibility), and iv) the worrisome decreasing fluoroquinolone and third-generation cephalosporin susceptibilities among Enterobacteriaceae. This laboratory-based survey depicts a contrasting situation and supports the scoring of patients for the resistant pathogen risk before empirical therapy.

Qualitative Review of Web-Based Professional Education on Antibiotic Prescribing for Children: 10 Million Hits, but Only 10 Good Web Sites

A structured Web-based search was performed to identify online educational programs on the optimal use of antibiotics in children. Identified Web sites of interest were classified using predefined quality criteria for educational Web resources. Of 10 Web sites identified, only 2 met all the quality criteria: APUA and Getsmart.

Ceftaroline in the management of complicated skin and soft tissue infections and community acquired pneumonia

Ceftaroline is a new parenteral cephalosporin approved by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) for the treatment of complicated skin and soft tissue infections (cSSTIs) including those due to methicillin-resistant Staphylococcus aureus (MRSA), and community-acquired pneumonia (CAP). Ceftaroline has broad-spectrum activity against gram-positive and gram-negative bacteria and exerts its bactericidal effects by binding to penicillin-binding proteins (PBPs), resulting in inhibition of bacterial cell wall synthesis. It binds to PBP 2a of MRSA with high affinity and also binds to all six PBPs in Streptococcus pneumoniae. In in vitro studies, ceftaroline demonstrated potent activity against Staphylococcus aureus (including MRSA and vancomycin-intermediate isolates), Streptococcus pneumoniae (including multidrug resistant isolates), Haemophilus influenzae, Moraxella catarrhalis, and many common gram-negative pathogens, excluding extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and Pseudomonas aeruginosa. In Phase II and Phase III clinical trials, ceftaroline was noninferior to its comparator agents and demonstrated high clinical cure rates in the treatment of cSSTIs and CAP. It demonstrated favorable outcomes in patients treated for both regulatory-approved indications and unlicensed indications in a retrospective analysis. Ceftaroline is a safe and effective option for treatment in specific patient populations in which its efficacy and safety have been proven. This article reviews the challenges in the treatment of cSSTI and CAP, ceftaroline and its microbiology, pharmacology, efficacy, and safety data which support its use in treatment of cSSTIs and CAP.

[In vitro activity of ceftaroline against Spanish isolates of Staphylococcus aureus: a multicenter study]

INTRODUCTION

Ceftaroline fosamil is a new-generation antimicrobial agent of cephalosporins subgroup. It is the first commercially available beta-lactam antibiotic that exhibits activity against methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study is to determine the in vitro Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values of ceftaroline against S.aureus strains (including MRSA).

MATERIAL AND METHODS

A multicenter study involving four hospitals representative of the Spanish geography was performed. MIC and MBC values against both the methicillin-resistant and sensitive strains of S.aureus (MRSA and methicillin-sensitive S.aureus [MSSA]) were determined using a broth microdilution method.

RESULTS

A total of 266 S.aureus strains were analyzed (95 MRSA and 171 MSSA). Ceftaroline bacterial sensitivity showed a mean MIC of 0.227 μg/ml (SD=0.146; range, 0.06 to 1 μg/ml). All MIC values of the 266 strains tested belonged to the sensitive category (value ≤ 1 μg/ml). Intermediate or resistant strains were not detected. MIC50 and MIC90 values for MRSA were 0.25 and 0.5 μg/ml, respectively (range=0.125-1 μg/ml). MSSA strains showed MIC50 and MIC90 values of 0.125 and 0.25 μg/ml, respectively (range=0.125-0.5 μg/ml). MBC50 and MBC90 values for MRSA were 0.5 and 1 μg/ml, respectively (range=0.125-1 μg/ml). MSSA strains showed MBC50 and MBC90 values of 0.25 and 0.25 μg/ml, respectively (range=0.125-0.5 μg/ml).

CONCLUSION

Ceftaroline shows excellent in vitro activity against S.aureus, including MRSA strains. Therefore, this antibiotic may be a promising alternative for the treatment of infections caused by this bacterium.

In vitro selection of single-stranded DNA molecular recognition elements against S. aureus alpha toxin and sensitive detection in human serum

Alpha toxin is one of the major virulence factors secreted by Staphylococcus aureus, a bacterium that is responsible for a wide variety of infections in both community and hospital settings. Due to the prevalence of S. aureus related infections and the emergence of methicillin-resistant S. aureus, rapid and accurate diagnosis of S. aureus infections is crucial in benefiting patient health outcomes. In this study, a rigorous Systematic Evolution of Ligands by Exponential Enrichment (SELEX) variant previously developed by our laboratory was utilized to select a single-stranded DNA molecular recognition element (MRE) targeting alpha toxin with high affinity and specificity. At the end of the 12-round selection, the selected MRE had an equilibrium dissociation constant (K_d) of 93.7 ± 7.0 nM. Additionally, a modified sandwich enzyme-linked immunosorbent assay (ELISA) was developed by using the selected ssDNA MRE as the toxin-capturing element and a sensitive detection of 200 nM alpha toxin in undiluted human serum samples was achieved.

Acute bacterial skin and skin structure infections (ABSSSI): practice guidelines for management and care transitions in the emergency department and hospital

BACKGROUND

Acute bacterial skin and skin structure infections (ABSSSI), formally referred to as complicated skin and soft tissue infections, include infections with resistance to previously effective antimicrobials. Increasing dramatically in incidence, they have become a challenging medical problem associated with high direct and indirect costs to both the medical system and society.

OBJECTIVES

To describe the burden of ABSSSI and to explore multidisciplinary approaches to its management and new treatments that can be initiated in the emergency department.

DISCUSSION

We offer a best practice model aimed at providing risk-stratified and convenient care for ABSSSI at the lowest possible cost, while minimizing complications, readmissions, and inappropriate antibiotic use. In doing so, we focus on the care provided by emergency physicians and hospitalists and the transition of management between them for inpatient care, as well as the facilitation of observation or direct-to-outpatient care for suitable patients.

CONCLUSIONS

A standard, consistent, and multidisciplinary approach to ABSSSI can streamline care, reduce admissions, support antimicrobial stewardship, and improve clinical and resource consumption outcomes.

Clinical and Economic Consequences of Failure of Initial Antibiotic Therapy for Hospitalized Patients With Complicated Skin and Skin-Structure Infections

Objective.

To estimate the consequences of failure of initial antibiotic therapy for patients with complicated skin and skin-structure infections.

Design.

Retrospective cohort study.

Setting.

Large US multihospital database.

Patients.

We identified a total of 47,219 patients (age 18 years or older) who were admitted to the hospital for complicated skin and skin-structure infections from April 1, 2003, through March 31, 2004, and who received intravenous antibiotics during the first 2 hospital-days (ie, initial antibiotic therapy). Failure of therapy was defined as drainage, debridement, or receipt of other intravenous antibiotics at any subsequent time (except for changes to narrower-spectrum agents or any therapy change immediately before discharge). Predictors of failure of antibiotic therapy and mortality were examined using multivariate logistic regression. Analysis of covariance was used to estimate the impact of treatment failure on duration of intravenous antibiotic therapy, length of stay, and total inpatient charges.

Results.

For 10,782 admitted patients (22.8%), there was evidence of failure of initial antibiotic therapy. In multivariate analyses, treatment failure was associated with receipt of vasoactive medications during the first 2 hospital-days (odds ratio [OR], 1.66 [95% confidence interval {CI}, 1.19-2.31]), initiation of antibiotic therapy in the intensive care unit (OR, 1.53 [95% CI, 1.28-1.84]), and the patient's Charlson comorbidity index (OR per 1-point increase, 1.06 [95% CI, 1.04-1.08]); treatment failure was also was associated with a 3-fold increase in mortality (OR, 2.91 [95% CI, 2.34-3.62]). Compared with patients for whom initial treatment was successful, patients who experienced treatment failure received intravenous antibiotic therapy for a mean of 5.7 additional days, were hospitalized for a mean of 5.4 additional days, and incurred a mean of $5,285 (in 2003 dollars) in additional inpatient charges (all P <.01).

Conclusion.

Failure of initial antibiotic therapy in the treatment of complicated skin and skin-structure infections is associated with significantly worse clinical and economic outcomes.

World Society of Emergency Surgery (WSES) guidelines for management of skin and soft tissue infections

Skin and soft tissue infections (SSTIs) encompass a variety of pathological conditions ranging from simple superficial infections to severe necrotizing soft tissue infections. Necrotizing soft tissue infections (NSTIs) are potentially life-threatening infections of any layer of the soft tissue compartment associated with widespread necrosis and systemic toxicity. Successful management of NSTIs involves prompt recognition, timely surgical debridement or drainage, resuscitation and appropriate antibiotic therapy. A worldwide international panel of experts developed evidence-based guidelines for management of soft tissue infections. The multifaceted nature of these infections has led to a collaboration among surgeons, intensive care and infectious diseases specialists, who have shared these guidelines, implementing clinical practice recommendations.

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.

A fatal case of multidrug resistant acinetobacter necrotizing fasciitis: the changing scary face of nosocomial infection

Necrotizing fasciitis is an uncommon soft-tissue infection, associated with high morbidity and mortality. Early recognition and treatment are crucial for survival. Acinetobacter baumannii is rarely associated with necrotizing fasciitis. Wound infections due to A. baumannii have been described in association with severe trauma in soldiers. There are only sporadic reports of monomicrobial A. baumannii necrotizing fasciitis. We report a unique case of monomicrobial necrotizing fasciitis caused by multidrug resistant (MDR) A. baumannii, in absence of any preceding trauma, surgery, or any obvious breech in the continuity of skin or mucosa. A 48-year-old woman with history of HIV, asthma, hypertension, and tobacco and excocaine use presented with acute respiratory failure requiring mechanical ventilation. She was treated for pneumonia for 7 days and was successfully extubated. All septic work-up was negative. Two days later, she developed rapidly spreading nonblanching edema with bleb formation at the lateral aspect of right thigh. Emergent extensive debridement and fasciotomy were performed. Operative findings and histopathology were consistent with necrotizing fasciitis. Despite extensive debridement, she succumbed to septic shock in the next few hours. Blood, wound, and tissue cultures grew A. baumannii, sensitive only to amikacin and polymyxin. Histopathology was consistent with necrotizing fasciitis.

Hospitalist perspective on the treatment of skin and soft tissue infections

The prevalence of skin and soft tissue infections (SSTIs) has been increasing in the United States. These infections are associated with an increase in hospital admissions. Hospitalists play an increasingly important role in the management of these infections and need to use hospital resources efficiently and effectively. When available, observation units are useful for treating low-risk patients who do not require hospital admission. Imaging tools may help to exclude abscesses and necrotizing soft tissue infections; however, surgical exploration remains the principal means of diagnosing necrotizing soft tissue infections. The most common pathogens that cause SSTIs are streptococci and Staphylococcus aureus. Methicillin-resistant S aureus (MRSA) is a prevalent pathogen, and concerns are increasing regarding the unclear distinctions between community-acquired and hospital-acquired MRSA. Other less frequent pathogens that cause SSTIs include Enterococcus species, Escherichia coli, Klebsiella species, Enterobacter species, and Pseudomonas aeruginosa. Cephalexin and clindamycin are suitable options for infections caused by streptococcal species and methicillin-susceptible S aureus. The increasing resistance of S aureus and Streptococcus pyogenes to erythromycin limits its use in these infections, and better alternatives are available. Parenteral cefazolin, nafcillin, or oxacillin can be used in hospitalized patients with nonpurulent cellulitis caused by streptococci and methicillin-susceptible S aureus. When oral MRSA therapy is indicated, clindamycin, doxycycline, trimethoprim-sulfamethoxazole, or linezolid is appropriate. Vancomycin, linezolid, daptomycin, tigecycline, telavancin, and ceftaroline fosamil are intravenous options that should be used in MRSA infections that require patient hospitalization. In the treatment of patients with SSTIs, hospitalists are at the forefront of providing proper patient care that reduces hospital costs, duration of therapy, and therapeutic failures. This review updates guidelines on the management of SSTIs with a focus on infections caused by S aureus, particularly MRSA, and outlines the role of the hospitalist in the effective management of SSTIs.

The Antimicrobial Activity of (-)-Epigallocatehin-3-Gallate and Green Tea Extracts against Pseudomonas aeruginosa and Escherichia coli Isolated from Skin Wounds

Background

Skin infections with Gram-negative bacteria are sometimes challenging to treat, because these bacteria show multidrug resistance against commonly used antibiotics and patients with Gram-negative bacterial infection overall have deteriorated in conditions in many cases. Studies have shown that epigallocatechin gallate (EGCG) and green tea extracts (GTE) inhibit the growth of several Gram-positive bacteria species.

Objective

The purpose of this study was to investigate the minimum inhibitory concentrations (MICs) of EGCG and GTE in Pseudomonas aeruginosa and Escherichia coli, and assess the use of these chemicals as an alternative or adjunct topical antimicrobial agent against P. aeruginosa and E. coli with multidrug resistance.

Methods

The MICs of EGCG, GTE, and other tested antibiotics were measured and compared to determine the antibacterial efficacy and the differences in pattern of resistance.

Results

The P. aeruginosa and E. coli strains used in this study showed multidrug resistance. EGCG inhibited the growth of P. aeruginosa at a MIC level of 200~400 µg/ml. The MIC of GTE was a 1 : 16 dilution for P. aeruginosa. EGCG showed antimicrobial activity against E. coli at a MIC of 400 µg/ml. In the case of GTE, the MIC was a dilution between 1:8 and 1:4 for E. coli.

Conclusion

EGCG and GTE showed potential as alternative or adjunct topical antimicrobial agents for infections that are resistant to traditional antibiotic therapy.

Chinese herbal medicines for treating skin and soft-tissue infections

BACKGROUND

Skin and soft-tissue infections (SSTIs) are common infections of the epidermis, dermis or subcutaneous tissue. SSTIs range in severity from minor, self-limiting, superficial infections to deep, aggressive, gangrenous, life-threatening infections. Some classifications divide SSTIs into 'complicated' and 'uncomplicated' infections based on clinical severity. Treatments of SSTIs involves antibiotic therapy, surgical debridement or drainage, and resuscitation if required. Sometimes these treatments are limited by high treatment costs, bacterial resistance to antibiotics and side effects, therefore, many people with SSTIs are turning to Chinese herbal medicines to treat this problem.Chinese herbal medicines are natural substances that have been used for centuries in China where they are generally considered to be effective for SSTIs. Some Chinese herbal medicines have been shown to have antibacterial and anti-inflammatory properties, although a few herbal medicines have been reported to have side effects. Therefore there is a need to review the current clinical evidence systematically to inform current practice and guide future studies on Chinese herbal medicines for SSTIs.

OBJECTIVES

To evaluate the benefits and harms of Chinese herbal medicines for treating skin and soft-tissue infections (SSTIs).

SEARCH METHODS

Searches were not restricted by date, language or publication status. In July 2014 we searched the following electronic databases: the 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; Ovid AMED (Allied and Complementary Medicine); and EBSCO CINAHL.

SELECTION CRITERIA

All randomised controlled trials (RCTs) in people with SSTIs that compared Chinese herbal medicines with another intervention or control.

DATA COLLECTION AND ANALYSIS

Two review authors screened the literature search results independently; there were no disagreements.

MAIN RESULTS

We identified no RCTs that met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is currently no information available from RCTs to support or refute the use of Chinese herbal medicines in treating people with SSTIs.

The safety and efficacy of daptomycin versus other antibiotics for skin and soft-tissue infections: a meta-analysis of randomised controlled trials

OBJECTIVE

Daptomycin, a cyclic lipopeptide that exhibits rapid, concentration-dependent bactericidal activity in vitro against a broad spectrum of Gram-positive pathogens, has now, since 2003, been approved in more than 70 countries and regions to treat skin and soft-tissue infections (SSTIs). The purpose of this meta-analysis was to compare the safety and efficacy of daptomycin with other antibiotics, especially with vancomycin which has long been considered the standard therapy for complicated SSTIs.

DESIGN

Meta-analysis of randomised controlled trials (RCTs).

DATA SOURCES

We thoroughly searched PubMed, EMBASE, Cochrane Central to identify relevant RCTs. Six RCTs with a total of 1710 patients were included in this meta-analysis.

RESULTS

The results demonstrated that the efficacy of daptomycin was at par with or maybe better than other first-line antibiotics for treating SSTIs as shown by the OR for clinical success (OR=1.05, 95% CI 0.84 to 1.31, p=0.65, I(2)=0%); daptomycin versus vancomycin subgroup (OR=1.19, 95% CI 0.77 to 1.83, p=0.43, I(2)=0%); overall microbiological success (OR=1.05, 95% CI 0.61 to 1.79, p=0.86, I(2)=42%); microbiological success of daptomycin versus comparators for Staphylococcus aureus (SA, OR=1.05, 95% CI 0.61 to 2.60, p=0.53, I(2)=47%), for methicillin-resistant S. aureus (OR=0.90, 95% CI 0.77 to 1.06, p=0.20, I(2)=56%). However, daptomycin tended to have a similar treatment-related adverse events (AEs) incidence in comparison with other antibiotics (OR=1.06, 95% CI 0.71 to 1.59, p=0.76, I(2)=41%). The trend showed that daptomycin might cause less discontinuation due to AEs and death compared with other first-line antibiotics (OR=0.71, 95% CI 0.46 to 1.10, p=0.12, I(2)=11%). Significantly more patients in the daptomyicn group had creatine phosphokinase elevation than those in the control group; however, it could be reversed when the therapy ended (OR=1.95, 95% CI 1.04 to 3.65, p=0.04, I(2)=0).

CONCLUSIONS

This meta-analysis demonstrated that the safety and efficacy of daptomycin was not inferior to that of other first-line drugs, and daptomycin tended to exhibit superior efficacy when compared with vancomycin or with comparators for SA infections; nevertheless, more high-quality RCTs are needed to draw a more credible conclusion.