Rapidly progressive soft tissue infections

Imaging of MSK infections in the ER

Musculoskeletal infections in the ER are not an uncommon presentation. The clinical context is critical in determining the suspicion for infection and degree of tissue involvement which can involve all layers from the skin to bones. The location, extent, and severity of clinically suspected infection directly relate to the type of imaging performed. Uncomplicated cellulitis typically does not require any imaging. Localized and superficial infections can mostly be evaluated with ultrasound. If there is a diffuse site (an entire extremity) or suspected deeper involvement (muscle/deep fascia), then CT is accurate in diagnosing, widely available, and performed quickly. With potential osseous involvement, MRI is the gold standard for diagnosing acute osteomyelitis; however, it has the drawbacks of longer scan times, artifacts including patient motion, and limited availability.

Topical Antiseptic Formulations for Skin and Soft Tissue Infections

Skin and soft tissue infections (SSTIs) are usually acute conditions of inflammatory microbial occupation of the skin layers and underlying soft tissues. SSTIs are one of the most frequent types of infection, typically requiring medical intervention and contribute to morbidity and mortality in both primary care and hospitalised patients. Due to the dramatic rise of antibiotic resistance, antiseptic agents can be potential alternatives for the prevention and treatment of SSTIs. Notably, they are commonly recommended in many global practical guidelines for use in per- and post- operative procedures. A range of antiseptics, including chlorhexidine, triclosan, alcohol, and povidone-iodine, are used and are mainly formulated as traditional, simple dosage forms such as solutions and semi-solids. However, in recent years, there have been studies reporting the potential for nanotechnology in the delivery of antiseptics. In this review, we have collated the scientific literature that focuses on topical antiseptic formulations for prevention and treatment of SSTIs, and have divided findings into traditional and advanced formulations. We conclude that although nanotechnological formulations have demonstrated potential advantages for delivering drugs; nevertheless, there is still scope for traditional formulations and further development of optimised topical formulations to address the rise of antimicrobial resistance.

Dynamic Changes in Microbial Composition During Necrotizing Soft-Tissue Infections in ICU Patients

Introduction: Recent studies described the threat of emerging multidrug-resistant (MDR) bacteria in intensive care unit (ICU) patients, but few data are available for necrotizing skin and soft tissue infections (NSTI). In a cohort of ICU patients admitted for NSTI, we describe the dynamic changes of microbial population during repeated surgeries.

Materials and Methods: This retrospective study compiled consecutive cases admitted for the management of severe NSTI. Clinical characteristics, NSTI features, morbidity and mortality data were collected. The microbiological characteristics of surgical samples obtained during initial surgery were compared with those obtained during the first reoperation, including persistence of initial pathogens and/or emergence of microorganisms. Risk factors for emergence of microorganisms and MDR bacteria were assessed by univariable and multivariable analyses.

Results: Among 100 patients {63% male, 58 years old [interquartile ratio (IQR) 50–68]} admitted for NSTI, 54 underwent reoperation with a median [IQR] delay of 3 (1–7) days. Decreased proportions of susceptible strains and emergence of Gram-negative bacteria, including Pseudomonas aeruginosa, staphylococci and enterococci strains, were reported based on the cultures of surgical specimen collected on reoperation. On reoperation, 22 (27%) of the isolated strains were MDR (p < 0.0001 vs. MDR bacteria cultured from the first samples). Broad-spectrum antibiotic therapy as first-line therapy was significantly associated with a decreased emergence of microorganisms. Adequate antibiotic therapy from the initial surgery did not modify the frequency of emergence of microorganisms (p = 0.79) and MDR bacteria (p = 1.0) or the 1-year survival rate.

Conclusion: The emergence of microorganisms, including MDR bacteria, is frequently noted in NSTI without affecting mortality.

Surgical Infection Society 2020 Updated Guidelines on the Management of Complicated Skin and Soft Tissue Infections

Background: The Surgical Infection Society (SIS) Guidelines for the treatment of complicated skin and soft tissue infections (SSTIs) were published in October 2009 in Surgical Infections. The purpose of this project was to provide a succinct update on the earlier guidelines based on an additional decade of data. Methods: We reviewed the previous guidelines eliminating bite wounds and diabetic foot infections including their associated references. Relevant articles on the topic of complicated SSTIs from 2008-2020 were reviewed and graded individually. Comparisons were then made between the old and the new graded recommendations with review of the older references by two authors when there was disparity between the grades. Results: The majority of new studies addressed antimicrobial options and duration of therapy particularly in complicated abscesses. There were fewer updated studies on diagnosis and specific operative interventions. Many of the topics addressed in the original guidelines had no new literature to evaluate. Conclusions: Most recommendations remain unchanged from the original guidelines with the exception of increased support for adjuvant antimicrobial therapy after drainage of complex abscess and increased data for the use of alternative antimicrobial agents.

An Update on the Treatment and Management of Cellulitis

Cellulitis and erysipelas are local soft tissue infections that occur following the entry of bacteria through a disrupted skin barrier. These infections are relatively common and early diagnosis is essential to treatment success. As dermatologists, we need to be familiar with the clinical presentation, diagnosis, and treatment of these infections. In this article, we provide a review of the literature and update on clinical manifestations, predisposing factors, microbiology, diagnosis, treatment, and complications. We also review the current situation in Chile.

Antibiotic therapy for skin and soft tissue infections: a protocol for a systematic review and network meta-analysis

BACKGROUND

Skin and soft tissue infections (SSTIs) in hospital and community settings impose a substantial socio-economic burden. Therapeutic uncertainty due to the availability of a wide range of antibiotics and the need for empirical treatment decisions complicate SSTI clinical management. Completion of numerous pairwise meta-analyses to account for this variability in antibiotics is impractical, and many head-to-head comparisons of potential interest are likely not available. In comparing multiple antibiotics simultaneously, this network meta-analysis aims to identify the antibiotic(s) with the greatest value in the treatment of SSTIs, in terms of patient-important outcomes such as efficacy and safety.

METHODS

We will conduct a systematic review to identify randomized controlled trials of persons with suspected or confirmed SSTI assigned to orally or parenterally administered antibiotic therapy that report results on at least one outcome of interest. We will search MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL), along with trial registries. Our primary outcome of interest is clinical success at the test-of-cure visit. Secondary outcomes may include (1) early clinical success (2-3 days after the therapy starts), (2) mortality, (3) adverse events, (4) treatment duration, and (5) length of hospital stay. Independent reviewers will complete screening of titles, abstracts, and full texts, data extraction, risk of bias assessment (using the Cochrane Risk of Bias tool), and evaluation of the certainty of evidence (using the GRADE approach) in duplicate. We will complete pairwise and network meta-analyses within the Bayesian framework when possible using a random effects model. We will stratify SSTIs by severity into uncomplicated and complicated SSTIs when possible. Subgroup analyses by age, infection type, comorbidity, and suspected or confirmed methicillin-resistant Staphylococcus aureus (MRSA)-associated infection are planned.

DISCUSSION

This study has several strengths compared to previous reviews: inclusion of a wider range of infection types, antibiotics, and outcomes; a comprehensive search strategy; a priori subgroup analyses; application of GRADE; and improved interpretability of findings through visual presentation of results. We hope our findings will inform future research, health care professionals, and policy makers resulting in improved evidence-based clinical management of SSTIs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018085607.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT COMMENTARY

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

Proteolytic signatures define unique thrombin-derived peptides present in human wound fluid in vivo

The disease burden of failing skin repair and non-healing ulcers is extensive. There is an unmet need for new diagnostic approaches to better predict healing activity and wound infection. Uncontrolled and excessive protease activity, of endogenous or bacterial origin, has been described as a major contributor to wound healing impairments. Proteolytic peptide patterns could therefore correlate and “report” healing activity and infection. This work describes a proof of principle delineating a strategy by which peptides from a selected protein, human thrombin, are detected and attributed to proteolytic actions. With a particular focus on thrombin-derived C-terminal peptides (TCP), we show that distinct peptide patterns are generated in vitro by the human S1 peptidases human neutrophil elastase and cathepsin G, and the bacterial M4 peptidases Pseudomonas aeruginosa elastase and Staphylococcus aureus aureolysin, respectively. Corresponding peptide sequences were identified in wound fluids from acute and non-healing ulcers, and notably, one peptide, FYT21 (FYTHVFRLKKWIQKVIDQFGE), was only present in wound fluid from non-healing ulcers colonized by P. aeruginosa and S. aureus. Our result is a proof of principle pointing at the possibility of defining peptide biomarkers reporting distinct proteolytic activities, of potential implication for improved diagnosis of wound healing and infection.

MKP-1 negative regulates Staphylococcus aureus induced inflammatory responses in Raw264.7 cells: roles of PKA-MKP-1 pathway and enhanced by rolipram

MAP phosphatases (MKP)-1 acts as an important regulator of innate immune response through a mechanism of control and attention both MAPK and NF-κB molecules during bacterial infection. However, the regulatory role of MKP-1 in the interplay between MAPK and NFκB pathway molecules is still not fully understood. In present study, we showed a direct interactions of p38, ERK or IκBα with MKP-1, and demonstrated that MKP-1 was a pivotal feedback control for both MAP kinases and NF-κB pathway in response to S. aureus. In addition, we found that rolipram had anti-inflammatory activity and repressed IκBα activation induced by S. aureus via PKA-MKP-1 pathway. Our report also demonstrated that PKA-cα can directly bind to IκBα upon S. aureus stimulation, which influenced the downstream signaling of PKA pathway, including altered the expression of MKP-1. These results presented a novel mechanism of PKA and IκB pathway, which may be targeted for treating S. aureus infection.

Interventions for the prevention of recurrent erysipelas and cellulitis

BACKGROUND

Erysipelas and cellulitis (hereafter referred to as 'cellulitis') are common bacterial skin infections usually affecting the lower extremities. Despite their burden of morbidity, the evidence for different prevention strategies is unclear.

OBJECTIVES

To assess the beneficial and adverse effects of antibiotic prophylaxis or other prophylactic interventions for the prevention of recurrent episodes of cellulitis in adults aged over 16.

SEARCH METHODS

We searched the following databases up to June 2016: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and LILACS. We also searched five trials registry databases, and checked reference lists of included studies and reviews for further references to relevant randomised controlled trials (RCTs). We searched two sets of dermatology conference proceedings, and BIOSIS Previews.

SELECTION CRITERIA

Randomised controlled trials evaluating any therapy for the prevention of recurrent cellulitis.

DATA COLLECTION AND ANALYSIS

Two authors independently carried out study selection, data extraction, assessment of risks of bias, and analyses. Our primary prespecified outcome was recurrence of cellulitis when on treatment and after treatment. Our secondary outcomes included incidence rate, time to next episode, hospitalisation, quality of life, development of resistance to antibiotics, adverse reactions and mortality.

MAIN RESULTS

We included six trials, with a total of 573 evaluable participants, who were aged on average between 50 and 70. There were few previous episodes of cellulitis in those recruited to the trials, ranging between one and four episodes per study.Five of the six included trials assessed prevention with antibiotics in participants with cellulitis of the legs, and one assessed selenium in participants with cellulitis of the arms. Among the studies assessing antibiotics, one study evaluated oral erythromycin (n = 32) and four studies assessed penicillin (n = 481). Treatment duration varied from six to 18 months, and two studies continued to follow up participants after discontinuation of prophylaxis, with a follow-up period of up to one and a half to two years. Four studies were single-centre, and two were multicentre; they were conducted in five countries: the UK, Sweden, Tunisia, Israel, and Austria.Based on five trials, antibiotic prophylaxis (at the end of the treatment phase ('on prophylaxis')) decreased the risk of cellulitis recurrence by 69%, compared to no treatment or placebo (risk ratio (RR) 0.31, 95% confidence interval (CI) 0.13 to 0.72; n = 513; P = 0.007), number needed to treat for an additional beneficial outcome (NNTB) six, (95% CI 5 to 15), and we rated the certainty of evidence for this outcome as moderate.Under prophylactic treatment and compared to no treatment or placebo, antibiotic prophylaxis reduced the incidence rate of cellulitis by 56% (RR 0.44, 95% CI 0.22 to 0.89; four studies; n = 473; P value = 0.02; moderate-certainty evidence) and significantly decreased the rate until the next episode of cellulitis (hazard ratio (HR) 0.51, 95% CI 0.34 to 0.78; three studies; n = 437; P = 0.002; moderate-certainty evidence).The protective effects of antibiotic did not last after prophylaxis had been stopped ('post-prophylaxis') for risk of cellulitis recurrence (RR 0.88, 95% CI 0.59 to 1.31; two studies; n = 287; P = 0.52), incidence rate of cellulitis (RR 0.94, 95% CI 0.65 to 1.36; two studies; n = 287; P = 0.74), and rate until next episode of cellulitis (HR 0.78, 95% CI 0.39 to 1.56; two studies; n = 287). Evidence was of low certainty.Effects are relevant mainly for people after at least two episodes of leg cellulitis occurring within a period up to three years.We found no significant differences in adverse effects or hospitalisation between antibiotic and no treatment or placebo; for adverse effects: RR 0.87, 95% CI 0.58 to 1.30; four studies; n = 469; P = 0.48; for hospitalisation: RR 0.77, 95% CI 0.37 to 1.57; three studies; n = 429; P = 0.47, with certainty of evidence rated low for these outcomes. The existing data did not allow us to fully explore its impact on length of hospital stay.The common adverse reactions were gastrointestinal symptoms, mainly nausea and diarrhoea; rash (severe cutaneous adverse reactions were not reported); and thrush. Three studies reported adverse effects that led to discontinuation of the assigned therapy. In one study (erythromycin), three participants reported abdominal pain and nausea, so their treatment was changed to penicillin. In another study, two participants treated with penicillin withdrew from treatment due to diarrhoea or nausea. In one study, around 10% of participants stopped treatment due to pain at the injection site (the active treatment group was given intramuscular injections of benzathine penicillin).None of the included studies assessed the development of antimicrobial resistance or quality-of-life measures.With regard to the risks of bias, two included studies were at low risk of bias and we judged three others as being at high risk of bias, mainly due to lack of blinding.

AUTHORS' CONCLUSIONS

In terms of recurrence, incidence, and time to next episode, antibiotic is probably an effective preventive treatment for recurrent cellulitis of the lower limbs in those under prophylactic treatment, compared with placebo or no treatment (moderate-certainty evidence). However, these preventive effects of antibiotics appear to diminish after they are discontinued (low-certainty evidence). Treatment with antibiotic does not trigger any serious adverse events, and those associated are minor, such as nausea and rash (low-certainty evidence). The evidence is limited to people with at least two past episodes of leg cellulitis within a time frame of up to three years, and none of the studies investigated other common interventions such as lymphoedema reduction methods or proper skin care. Larger, high-quality studies are warranted, including long-term follow-up and other prophylactic measures.

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.

[Necrotizing Soft Tissue Infection Caused by Serratia marcescens in a Patient Treated with Tocilizumab]

We report herein on a case of community-acquired necrotizing soft tissue infection caused by Serratia marcescens. The patient had been treated with prednisolone, tocilizumab and tacrolimus for rheumatoid arthritis. Since Gram staining of the tissue revealed Gram negative rod bacteria, ceftriaxone and clindamycin were administered as empiric therapy. Tissue culture revealed S. marcescens. Ceftriaxone was continued according to the antibiotic sensitivity. She underwent debridement of necrotic tissue and continued ceftriaxone for 17 days. She recovered and was discharged after skin grafting.

Septic arthritis and subsequent fatal septic shock caused by Vibrio vulnificus infection

Vibrio vulnificus is a rare but potential fatal bacterium that can cause severe infections. Wound infections, primary sepsis and gastroenteritis are the most common clinical features. Septic arthritis caused by V. vulnificus is an atypical presentation that has been reported in only two case reports; however, it has not been previously noted in Denmark. The authors report a case of septic arthritis caused by V. vulnificus in an immunocompromised patient. The disease progressed to severe sepsis and subsequent death within 10 h of admission.

Lower Extremity Wounds in Patients With Idiopathic Thrombocytopenic Purpura and Systemic Lupus Erythematosus

Infections in lower extremities are sometimes concerned with systemic immunological disorders such as idiopathic thrombocytopenic purpura and systemic lupus erythematosus, which are treated with systemic steroids. Steroid therapy impairs the epithelial wound healing and with systemic condition, especially with systemic lupus erythematosus, the wound is susceptible for infection. Even a pyoderma gangrenosum sometimes occurs in a patient with idiopathic thrombocytopenic purpura with an incisional wound of hernia. The severe signs and symptoms are the deep skin and soft tissue infections, mainly caused by group A streptococcus, composed of necrotizing fasciitis and muscle necrosis. Medically suspected necrotizing fasciitis patients should be empirically and immediately administered with broad-spectrum antibiotics, which may cover the common suspected pathogens. In type I (polymicrobial) infection, the selection of antimicrobial should be based on medical history and Gram staining and culture. The coverage against anaerobes is important in type I infection. Metronidazole, clindamycin, or beta-lactams with beta-lactamase inhibitor or carbapenems are the treatment of choice against anaerobes, while early surgical debridement-wide enough and deep enough-is the core treatment of necrotizing fasciitis and results in significantly better mortality compared with those who underwent surgery after a few hours of delay. When necrotizing fasciitis is considered and the patient is brought to the operation room, aggressive and extensive surgical debridement is explored. Tissue involved should be completely removed until no further evidence of infection is seen. When further debridement is required, the patient must return to the operating room immediately. In this context, the temporal coverage using the artificial dermis after debridement is useful because there is no loss of the patient's own tissue and yet it is easier for "second-look" surgery or secondary reconstruction, and extensive enough debridement is always the mainstay of the therapy.

Novel phospholipase A2 inhibitors from python serum are potent peptide antibiotics

Antimicrobial peptides (AMPs) play a vital role in defense against resistant bacteria. In this study, eight different AMPs synthesized from Python reticulatus serum protein were tested for bactericidal activity against various Gram-positive and Gram-negative bacteria (Staphylococcus aureus, Burkholderia pseudomallei (KHW and TES strains), and Proteus vulgaris) using a disc-diffusion method (20 μg/disc). Among the tested peptides, phospholipase A2 inhibitory peptide (PIP)-18[59-76], β-Asp65-PIP[59-67], D-Ala66-PNT.II, and D60,65E-PIP[59-67] displayed the most potent bactericidal activity against all tested pathogens in a dose-dependent manner (100-6.8 μg/ml), with a remarkable activity noted against S. aureus at 6.8 μg/ml dose within 6 h of incubation. Determination of minimum inhibitory concentrations (MICs) by a micro-broth dilution method at 100-3.125 μg/ml revealed that PIP-18[59-76], β-Asp65-PIP[59-67] and D-Ala66-PNT.II peptides exerted a potent inhibitory effect against S. aureus and B. pseudomallei (KHW) (MICs 3.125 μg/ml), while a much less inhibitory potency (MICs 12.5 μg/ml) was noted for β-Asp65-PIP[59-67] and D-Ala66-PNT.II peptides against B. pseudomallei (TES). Higher doses of peptides had no effect on the other two strains (i.e., Klebsiella pneumoniae and Streptococcus pneumoniae). Overall, PIP-18[59-76] possessed higher antimicrobial activity than that of chloramphenicol (CHL), ceftazidime (CF) and streptomycin (ST) (30 μg/disc). When the two most active peptides, PIP-18[59-76] and β-Asp65-PIP[59-67], were applied topically at a 150 mg/kg dose for testing wound healing activity in a mouse model of S. aureus infection, the former accelerates faster wound healing than the latter peptide at 14 days post-treatment. The western blot data suggest that the topical application of peptides (PIP-18[59-67] and β-Asp65-PIP[59-67]) modulates NF-kB mediated wound repair in mice with relatively little haemolytic (100-1.56 μg/ml) and cytotoxic (1000-3.125 μg/ml) effects evident on human cells in vitro.

Tetanus after envenomations caused by freshwater stingrays

Injuries caused by freshwater stingray are common in several regions of South America, although they are underreported. The riverside inhabitants are the main victims in the Amazonian and Midwest regions of South America. The fishermen are injured mainly in the new focus of colonization of the rivers by freshwater stingrays. With the increasing population in these regions, where freshwater stingrays are found, there has been a significant increase in injuries within the general population. The highest increase occurred among tourists from other regions, where these animals are not known, when visiting these areas. The envenomations from the stingray causes prolonged and intense pain, both local and regionally. Generally these are associated with other local inflammatory manifestations, such as swelling and erythema. The injury often progresses to necrosis and it is considered potentially tetanogenic. A secondary infection is also a frequent local complication and most frequently is caused by Aeromonas species, usually Aeromonas hydrophila. Herein we report the first 2 cases of tetanus after freshwater stingray injuries: a 51-year-old men who had tetanus and recovered without sequel and the second a 67-year-old men who had severe tetanus and a deep, necrotizing soft-tissue infection with sepsis, septic shock and evolution to death.

Skin electroporation of a plasmid encoding hCAP-18/LL-37 host defense peptide promotes wound healing

Host defense peptides, in particular LL-37, are emerging as potential therapeutics for promoting wound healing and inhibiting bacterial growth. However, effective delivery of the LL-37 peptide remains limiting. We hypothesized that skin-targeted electroporation of a plasmid encoding hCAP-18/LL-37 would promote the healing of wounds. The plasmid was efficiently delivered to full-thickness skin wounds by electroporation and it induced expression of LL-37 in the epithelium. It significantly accelerated reepithelialization of nondiabetic and diabetic wounds and caused a significant VEGFa and interleukin (IL)-6 induction. IL-6 was involved in LL-37-mediated keratinocyte migration in vitro and IL-6 neutralizing antibodies delivered to mice were able to suppress the wound healing activity of the hCAP-18/LL-37 plasmid. In a hindlimb ischemia model, electroporation of the hCAP-18/LL-37 plasmid increased blood perfusion, reduced muscular atrophy, and upregulated the angiogenic chemokines VEGFa and SDF-1a, and their receptors VEGF-R and CXCR-4. These findings demonstrate that a localized gene therapy with LL-37 is a promising approach for the treatment of wounds.

The Laboratory Risk Indicator for Necrotizing Fasciitis score for discernment of necrotizing fasciitis originated from Vibrio vulnificus infections

BACKGROUND

The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score has been verified as a useful diagnostic tool for detecting necrotizing fasciitis (NF). Its application, however, is mainly for NF types I and II. The practical relevance of the LRINEC score for Vibro vulnificus-related skin and soft tissue infection (SSTI) was hardly ever investigated. The aim of this study was to assess the applicability of the LRINEC scoring system and to identify NF-predicting factors in patients with V. vulnificus-caused SSTI.

METHODS

A retrospective study was conducted, enrolling 125 consecutive patients diagnosed with V. vulnificus-related SSTI who were admitted to a teaching hospital between January 2003 and December 2011. Demographics, laboratory data, comorbidities, treatment, and outcomes were collected for each patient and extracted for analysis. Logistic regression and receiver operating characteristic curve analyses were performed.

RESULTS

The mean (SD) age of the 125 patients was 63.0 (10.9) years; 58% of the patients were male. The mean (SD) LRINEC score at admission was 2.4 (1.9) points. Of the 125 patents, 72 (58%) had NF. Multivariate analysis revealed that the presence of hemorrhagic bullous lesions (p = 0.002) and higher LRINEC scores at admission (p < 0.0001) were significantly associated with the presence of NF. In addition, the area under the receiver operating characteristic curve for the LRINEC scoring model for detecting NF was 0.783 (p < 0.0001). An optimal cutoff LRINEC score of 2 or greater had a sensitivity of 71%, a specificity of 83%, and a positive predictive value of 85%, with an 11.9-fold increased risk for the presence of NF (p < 0.0001).

CONCLUSION

We have demonstrated that the LRINEC score and hemorrhagic bullous/blistering lesions are significant predictors of NF in patients with V. vulnificus-related SSTI. V. vulnificus-infected patients having hemorrhagic bullous/blistering lesions or with an LRINEC score of 2 or greater should be thoughtfully evaluated for the presence of NF.

LEVEL OF EVIDENCE

Diagnostic test study, level II.

Incidence, microbiology, and patient characteristics of skin and soft-tissue infections in a U.S. population: a retrospective population-based study

Background

Skin and soft tissue infections (SSTIs) are commonly occurring infections with wide-ranging clinical manifestations, from mild to life-threatening. There are few population-based studies of SSTIs in the period after the rapid increase in community-acquired methicillin-resistant Staphyloccus aureus (MRSA).

Methods

We used electronic databases to describe the incidence, microbiology, and patient characteristics of clinically-diagnosed skin and soft tissue infections (SSTIs) among members of a Northern California integrated health plan. We identified demographic risk factors associated with SSTIs and MRSA infection.

Results

During the three-year study period from 2009 to 2011, 376,262 individuals experienced 471,550 SSTI episodes, of which 23% were cultured. Among cultured episodes, 54% were pathogen-positive. Staphylococcus aureus (S. aureus) was isolated in 81% of pathogen-positive specimens, of which nearly half (46%) were MRSA. The rate of clinically-diagnosed SSTIs in this population was 496 per 10,000 person-years. After adjusting for age group, gender, race/ethnicity and diabetes, Asians and Hispanics were at reduced risk of SSTIs compared to whites, while diabetics were at substantially higher risk compared to non-diabetics. There were strong age group by race/ethnicity interactions, with African Americans aged 18 to <50 years being disproportionately at risk for SSTIs compared to persons in that age group belonging to other race/ethnicity groups. Compared to Whites, S. aureus isolates of African-Americans and Hispanics were more likely to be MRSA (Odds Ratio (OR): 1.79, Confidence Interval (CI): 1.67 to 1.92, and, OR: 1.24, CI: 1.18 to 1.31, respectively), while isolates from Asians were less likely to be MRSA (OR: 0.73, CI: 0.68 to 0.78).

Conclusions

SSTIs represent a significant burden to the health care system. The majority of culture-positive SSTIs were caused by S. aureus, and almost half of the S. aureus SSTIs were methicillin-resistant. The reasons for African-Americans having a higher likelihood, and Asians a lower likelihood, for their S. aureus isolates to be methicillin-resistant, should be further investigated.

Microbiology of skin and soft tissue infections in the age of community-acquired methicillin-resistant Staphylococcus aureus

The objectives of this study were to determine the etiology of skin and soft-tissue infections (SSTIs) in a general population, and to describe patient characteristics, SSTI types, frequency of microbiologic testing, and the role of methicillin-resistant Staphylococcus aureus (MRSA) over time. Using electronic databases, we identified SSTI episodes and microbiologic testing among members of a large US health plan. Between 2006 and 2009, 648699 SSTI episodes were identified, of which 23% had a specimen, of which 15% were blood. A pathogen was identified in 58% of SSTI cultures. S. aureus was the most common pathogen (80% of positive cultures). Half of S. aureus isolates were MRSA. Among cellulitis and abscess episodes with a positive blood culture, 21% were methicillin-sensitive S. aureus, 16% were MRSA, 21% were beta-hemolytic streptococci and 28% were Gram negative bacteria. Between 1998 and 2009, the percentage of SSTIs for which a culture was obtained increased from 11% to 24%. In SSTI episodes with a culture-confirmed pathogen, MRSA increased from 5% in 1998 to 9% in 2001 to 42% in 2005, decreasing to 37% in 2009. These data can inform the choice of antibiotics for treatment of SSTIs.

Necrotizing soft-tissue infections

NSTI is a life-threatening, surgical, and medical emergency. Clinical presentation, at least in the initial phase, can be misleading. Various studies have shown that delay in surgical debridement is associated with increased mortality. A high index of suspicion is important in early recognition and in instituting prompt therapy without delay. Early diagnosis, aggressive surgical debridement, aggressive supportive care, and optimal presumptive antibiotic therapy significantly improve morbidity and mortality associated with NSTIs.

Cysteine proteinase SpeB from Streptococcus pyogenes - a potent modifier of immunologically important host and bacterial proteins

Group A streptococcus (Streptococcus pyogenes) is an exclusively human pathogen that causes a wide spectrum of diseases ranging from pharyngitis, to impetigo, to toxic shock, to necrotizing fasciitis. The diversity of these disease states necessitates that S. pyogenes possess the ability to modulate both the innate and adaptive immune responses. SpeB, a cysteine proteinase, is the predominant secreted protein from S. pyogenes. Because of its relatively indiscriminant specificity, this enzyme has been shown to degrade the extracellular matrix, cytokines, chemokines, complement components, immunoglobulins, and serum protease inhibitors, to name but a few of the known substrates. Additionally, SpeB regulates other streptococcal proteins by degrading them or releasing them from the bacterial surface. Despite the wealth of literature on putative SpeB functions, there remains much controversy about this enzyme because many of reported activities would produce contradictory physiological results. Here we review all known host and bacterial protein substrates for SpeB, their cleavage sites, and discuss the role of this enzyme in streptococcal pathogenesis based on the current literature.

Bacterial skin and soft tissue infections: review of the epidemiology, microbiology, aetiopathogenesis and treatment: a collaboration between dermatologists and infectivologists

Bacterial skin and soft tissues infections (SSTI) often determine acute disease and frequent emergency recovering, and they are one of the most common causes of infection among groups of different ages. Given the variable presentation of SSTI, a thorough assessment of their incidence and prevalence is difficult. The presence of patient-related (local or systemic) or environmental risk factors, along with the emergence of multi-drug resistant pathogens, can promote SSTI. These infections may present with a wide spectrum of clinical features and different severity, and can be classified according to various criteria. Many bacterial species can cause SSTI, but Gram-positive bacteria are the most frequently isolated, with a predominance of Staphylococcus aureus and Streptococcus pyogenes. The diagnosis of SSTI requires an extended clinical history, a thorough physical examination and a high index of suspicion. Early diagnosis is particularly important in complicated infections, which often require laboratory studies, diagnostic imaging and surgical exploration. SSTI management should conform to the epidemiology, the aetiology, the severity and the depth of the infection. Topical, oral or systemic antimicrobial therapy and drainage or debridement could be necessary, along with treatment of a significant underlying disease. This review discusses the epidemiology, the pathogenesis and the classification of bacterial SSTI, describes their associated risk factors and their clinical presentations. The authors provide a rational diagnostic and therapeutic approach to SSTI in respect of antibiotic resistance and currently available antimicrobial agents.

Serious and life-threatening pregnancy-related infections: opportunities to reduce the global burden

Michael Gravett and colleagues review the burden of pregnancy-related infections, especially in low- and middle-income countries, and offer suggestions for a more effective intervention strategy.

Cysteine proteinase SpeB from Streptococcus pyogenes - a potent modifier of immunologically important host and bacterial proteins

Group A streptococcus (Streptococcus pyogenes) is an exclusively human pathogen that causes a wide spectrum of diseases ranging from pharyngitis, to impetigo, to toxic shock, to necrotizing fasciitis. The diversity of these disease states necessitates that S. pyogenes possess the ability to modulate both the innate and adaptive immune responses. SpeB, a cysteine proteinase, is the predominant secreted protein from S. pyogenes. Because of its relatively indiscriminant specificity, this enzyme has been shown to degrade the extracellular matrix, cytokines, chemokines, complement components, immunoglobulins, and serum protease inhibitors, to name but a few of the known substrates. Additionally, SpeB regulates other streptococcal proteins by degrading them or releasing them from the bacterial surface. Despite the wealth of literature on putative SpeB functions, there remains much controversy about this enzyme because many of reported activities would produce contradictory physiological results. Here we review all known host and bacterial protein substrates for SpeB, their cleavage sites, and discuss the role of this enzyme in streptococcal pathogenesis based on the current literature.

Frequency and antibiotic susceptibility of gram-positive bacteria in Makkah hospitals

BACKGROUND AND OBJECTIVE

Gram-positive bacteria are important nosocomial pathogens. The objective of this study was to estimate the frequencies and resistance rates of gram-positive pathogens isolated from hospitals in Makkah, Saudi Arabia.

DESIGN AND SETTING

Prospective study at three Makkah hospitals from May 2008 to April 2009.

PATIENTS AND METHODS

Clinical isolates were collected and demographic and laboratory data were recorded. Standard microbiological methods were used to identify the organisms and test for antimicrobial susceptibility. The results were interpreted according to the Clinical Laboratory Standards Institute (CLSI) guidelines.

RESULTS

Clinical isolates were collected from 1087 patients. Gram-positive pathogens infected all age groups, but had no gender predominance. Staphylococcus aureus was the most common cause of wound infection and accounted for more than half of the clinical isolates (688 cases). Coagulase-negative staphylococcus (CONS) was a common isolate from blood cultures. Wounds were the most common site of infection (37.6%). Enterococcus spp. and Streptococcus agalactiae were the second most common bacteria (26%). The resistance rates of S aureus and CONS isolates were 39.4% and 82.4% for oxacillin, respectively. Among the streptococci, the resistance rates of Streptococcus pneumoniae were 21.1% and 16.7% for ampicillin and erythromycin, respectively.

CONCLUSIONS

S aureus infections were found to be very common in the Makkah hospitals. Infection prevention, control measures and continuous monitoring for antibiotic susceptibility are necessary to reduce these and other nosocomial infections.

Meropenem in the treatment of complicated skin and soft tissue infections

Meropenem is a broad-spectrum carbapenem antibiotic with excellent activity against many pathogens associated with complicated skin and soft tissue infections (cSSTIs). At least three studies have shown meropenem to have good clinical efficacy and to be well tolerated in the treatment of cSSTIs. Two open-label studies compared meropenem 500 mg every 8 hours (total evaluable n=146) with imipenem/cilastatin 500mg every 6 hours (n=147). Clinical efficacy rates in evaluable patients 7–14 days after end of treatment were similar, 92% and 100% in meropenem-treated groups versus 89% and 100% in groups receiving imipenem/cilastatin. An additional prospective, randomized, double-blind study evaluated meropenem 500mg every 8 hours (261 evaluable patients) versus imipenem/cilastatin 500 mg every 8 hours (287 patients). Clinical efficacy rates of meropenem and imipenem/cilastatin 7–28 days after end of treatment were 86.2% and 82.9%, respectively. Meropenem was well tolerated in all studies. Carbapenems are currently recommended as appropriate for initial treatment of certain cSSTIs such as those likely to involve mixed and/or multidrug-resistant pathogens. Meropenem is an effective and safe alternative for monotherapy when used for appropriate types of cSSTIs. Higher doses (ie, 1 g every 8 hours) should be considered for treatment of cSSTIs in higher-risk patients where Pseudomonas aeruginosa is a suspected or documented pathogen.

Bacterial skin and soft tissue infections in adults: A review of their epidemiology, pathogenesis, diagnosis, treatment and site of care

Skin and soft tissue infections (SSTIs) involve microbial invasion of the skin and underlying soft tissues. They have variable presentations, etiologies and severities. The challenge of SSTIs is to efficiently differentiate those cases that require immediate attention and intervention, whether medical or surgical, from those that are less severe. Approximately 7% to 10% of hospitalized patients are affected by SSTIs, and they are very common in the emergency care setting. The skin has an extremely diverse ecology of organisms that may produce infection. The clinical manifestations of SSTIs are the culmination of a two-step process involving invasion and the interaction of bacteria with host defences. The cardinal signs of SSTIs involve the features of inflammatory response, with other manifestations such as fever, rapid progression of lesions and bullae. The diagnosis of SSTIs is difficult because they may commonly masquerade as other clinical syndromes. To improve the management of SSTIs, the development of a severity stratification approach to determine site of care and appropriate empirical treatment is advantageous. The selection of antimicrobial therapy is predicated on knowledge of the potential pathogens, the instrument of entry, disease severity and clinical complications. For uncomplicated mild to moderate infections, the oral route suffices, whereas for complicated severe infections, intravenous administration of antibiotics is warranted. Recognition of the potential for resistant pathogens causing SSTIs can assist in guiding appropriate selection of antibiotic therapy.

Severe skin and soft tissue infections and associated critical illness

Skin and soft tissue infections (SSTIs) span a broad spectrum of clinical entities from limited cellulitis to rapidly progressive necrotizing fasciitis, which may be associated with septic shock or a toxic shock-like syndrome. These infections may be the primary instigators of critical illness requiring hospitalization and management in the intensive care unit. Alternatively, these infections may arise from metastatic spread of microorganisms from a distant focus. Regardless of the source, SSTIs may lead to critical illness. The complex interplay of environment, host, and pathogen are important to consider when evaluating SSTIs and planning therapy. This second of a two-part review focuses on severe SSTIs due to Clostridium spp, microorganisms associated with water sources, and polymicrobial/mixed infections. The key to a successful outcome is early identification of risk factors for specific pathogens and early initiation of empiric antimicrobial therapy. For some SSTIs, surgical intervention for diagnosis and/or therapy is also required.

Murine model of cutaneous infection with Streptococcus pyogenes

Despite the medical advances achieved during the last century to fight against bacteria, viruses, fungi and parasites, infectious diseases are still a major cause of death, disability, and social and economic upheaval for millions around the world. Challenges remain in countering microorganisms even where antibiotics and vaccines are available. Much remains to be learned about basic aspects of the host-pathogen relationship and the complexity of the immune response to infection. Animal models represent a powerful tool to dissect the host response to infection, as well as the pathogenesis of the microbe. One of the advantages of using animal models is that both genetic and environmental factors that may influence the course of an infection can be controlled, allowing a precise cause-effect analysis of the host-pathogen interactions. In addition, there are no real alternatives to whole animal models in the study of integrative physiology and dynamic pathophysiologic alterations. The use of animal models has also proven invaluable for testing the efficacy of experimental antimicrobial agents and their therapeutic regimes. The mouse model is the most widely used for many reasons, including its cost effectiveness, the high number of immunological reagents available for this species, and the relative ease of biocontainment. Mouse strains with specific properties such as transgenic mouse strains with gene insertion or targeted mutation (knock-out) are very effective tools for studying the role of specific genes controlling the immune response to infectious pathogens. Murine models will remain the most appropriate tool for evaluating new therapeutic strategies for the treatment of various diseases. The closer the model is adapted to the human disease, the more reliable will be the results.In this chapter, the experimental procedures required to establish a mouse model of cutaneous and soft tissue infection are detailed. This model has provided invaluable insights into the pathogenicity of the agent for the human host.

Soft tissue infections and emergency department disposition: predicting the need for inpatient admission

OBJECTIVES

Little empiric evidence exists to guide emergency department (ED) disposition of patients presenting with soft tissue infections. This study's objective was to generate a clinical decision rule to predict the need for greater than 24-hour hospital admission for patients presenting to the ED with soft tissue infection.

METHODS

This was a retrospective cohort study of consecutive patients presenting to a tertiary care hospital ED with diagnosis of nonfacial soft tissue infection. Standardized chart review was used to collect 29 clinical variables. The primary outcome was >24-hour hospital admission (either general admission or ED observation unit), regardless of initial disposition. Patients initially discharged home and later admitted for more than 24 hours were included in the outcome. Data were analyzed using classification and regression tree (CART) analysis and multivariable logistic regression.

RESULTS

A total of 846 patients presented to the ED with nonfacial soft tissue infection. After merging duplicate records, 674 patients remained, of which 81 (12%) required longer than 24-hour admission. Using CART, the strongest predictors of >24-hour admission were patient temperature at ED presentation and mechanism of infection. In the multivariable logistic regression model, initial patient temperature (odds ratio [OR] for each degree over 37 degrees C = 2.91, 95% confidence interval [CI] = 1.65 to 5.12) and history of fever (OR = 3.02, 95% CI = 1.41 to 6.43) remained the strongest predictors of hospital admission. Despite these findings, there was no combination of factors that reliably identified more than 90% of target patients.

CONCLUSIONS

Although we were unable to generate a high-sensitivity decision rule to identify ED patients with soft tissue infection requiring >24-hour admission, the presence of a fever (either by initial ED vital signs or by history) was the strongest predictor of need for >24-hour hospital stay. These findings may help guide disposition of patients presenting to the ED with nonfacial soft tissue infections.

Skin and soft tissue infections

Skin and soft tissue infections are a common cause of hospitalization and use of antibiotic therapy, and may result in significant disability. Infections managed by surgeons may vary from simple, noncomplicated cellulitis to severe necrotizing soft tissue infections. The differentiation of necrotizing infections from nonnecrotizing infections is critical to achieving adequate surgical therapy. An understanding of the changing epidemiology of all complicated skin and soft tissue infections is required for selection of appropriate empiric antibiotic therapy.

SpeB of Streptococcus pyogenes differentially modulates antibacterial and receptor activating properties of human chemokines

Background

CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG/CXCL9, IP–10/CXCL10 and I–TAC/CXCL11, are antibacterial for Streptococcus pyogenes.

Methodology/Principal Findings

SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10/CXCL10, I-TAC/CXCL11, PF4/CXCL4, GROα/CXCL1, GROβ/CXCL2, GROγ/CXCL3, ENA78/CXCL5, GCP-2/CXCL6, NAP-2/CXCL7, SDF-1/CXCL12, BCA-1/CXCL13, BRAK/CXCL14, SRPSOX/CXCL16, MIP-3α/CCL20, Lymphotactin/XCL1, and Fractalkine/CX3CL1), has no activity on IL-8/CXCL8 and RANTES/CCL5, partly degrades SRPSOX/CXCL16 and MIP-3α/CCL20, and releases a 6 kDa CXCL9 fragment. CXCL10 and CXCL11 loose receptor activating and antibacterial activities, while the CXCL9 fragment does not activate the receptor CXCR3 but retains its antibacterial activity.

Conclusions/Significance

SpeB destroys most of the signaling and antibacterial properties of chemokines expressed by an inflamed epithelium. The exception is CXCL9 that preserves its antibacterial activity after hydrolysis, emphasizing its role as a major antimicrobial on inflamed epithelium.

Aeromonas hydrophila sepsis with septic embolism and rhabdomyolysis in a chronic iron overload haemodialysis patient treated with deferoxamine

Aeromonas infection in humans is associated with certain underlying diseases, especially chronic liver disease or malignancy. However, Aeromonas infection associated with iron overload is rarely reported. We report a case of a 47-year-old female with end-stage renal disease on haemodialysis and on deferoxamine treatment for iron overload who developed Aeromonas sepsis with septic embolism and rhabdomyolysis. Although the patients with Aeromonas infection and rhabdomyolysis have been correlated with high mortality, this reported case survived. We suggest that a chronic haemodialysis patient on deferoxamine treatment for iron overload is vulnerable to Aeromonas infection. In such cases, the clinician should be alerted to the possibility of rhabdomyolsis, and frequent haemodialysis is necessary.

Are glycopeptides still appropriate and convenient for empiric use?

The glycopeptides vancomycin and teicoplanin are widely used, and indeed recommended for, the treatment of severe or resistant Gram-positive infections. Therapeutic drug monitoring is widely used for vancomycin but less commonly for teicoplanin, and remains controversial. We report the cost savings of a formulary decision to replace teicoplanin with daptomycin for the empiric treatment of complicated skin and soft tissue infections (CSSTIs), staphylococcal bacteraemia and hospital-acquired Gram-positive sepsis. In the Intensive Therapy Unit (ITU) we optimised treatment of serious Gram-positive infections by substituting teicoplanin with vancomycin administered by continuous infusion. Costs were calculated using British National Formulary (BNF) prices and costs for therapeutic drug monitoring. Daptomycin (350 mg/d) use was associated with a cost saving per 7 days of treatment of 86 pounds and vancomycin with 51 pounds (4 g/d) to 276 pounds (2 g/d) compared to the 600 mg teicoplanin dose. Our own formulary re-positioning of glyco/lipopeptides, i.e. the preferential use of vancomycin in the ITU and substitution of teicoplanin with daptomycin, is cost-effective and provides better therapeutic alternatives. Continuous vancomycin infusion in the ITU setting guarantees optimal dosing for severely ill patients. Daptomycin use on surgical and medical wards, apart from being marginally cheaper than teicoplanin, guarantees optimal dosing without the need for drug monitoring.

Host defense peptides in wound healing

Host defense peptides are effector molecules of the innate immune system. They show broad antimicrobial action against gram-positive and -negative bacteria, and they likely play a key role in activating and mediating the innate as well as adaptive immune response in infection and inflammation. These features make them of high interest for wound healing research. Non-healing and infected wounds are a major problem in patient care and health care spending. Increasing infection rates, growing bacterial resistance to common antibiotics, and the lack of effective therapeutic options for the treatment of problematic wounds emphasize the need for new approaches in therapy and pathophysiologic understanding. This review focuses on the current knowledge of host defense peptides affecting wound healing and infection. We discuss the current data and highlight the potential future developments in this field of research.

Adherence to Standard Operating Procedures is Crucial for Intensive Care Unit Survival of Elderly Patients

Elderly patients account for 42–52% of intensive care unit (ICU) admissions and for almost 60% of all ICU days in the USA and up to 50% receive inappropriate antibiotic treatment. The aim of this study was to evaluate whether adherence to Standard Operating Procedures (SOPs) reduced ICU mortality in an elderly population. The study included consecutive patients ( n = 228) aged ≤ 60 years with an ICU stay of > 72 h. SOPs were based on evidence-based medicine guidelines for diagnosis and treatment of infections, and on local resistance rates. According to preset indicators of quality management standards and assessment of different degrees of adherence, an implementation rate > 70% was considered adherent (high adherence group [HAG]) and ≤ 70% was considered non-adherent (low adherence group [LAG]). Patients in the HAG ( n = 137) had significantly reduced mortality compared with LAG patients ( n = 91): 5.8% versus 19.8%, respectively. It was concluded that adherence to SOPs based on evidence-based medicine that consider local resistance rates for antibiotic treatment in elderly ICU patients is associated with a lower mortality rate.