Serious Complications from Staphylococcal aureus in Atopic Dermatitis

Secondary Bacterial Infections in Patients with Atopic Dermatitis or Other Common Dermatoses

Secondary bacterial infections of common dermatoses such as atopic dermatitis, ectoparasitosis, and varicella zoster virus infections are frequent, with Staphylococcus aureus and Streptococcus pyogenes being the bacteria most involved. There are also Gram-negative infections secondary to common dermatoses such as foot dyshidrotic eczema and tinea pedis. Factors favoring secondary bacterial infections in atopic dermatitis, ectoparasitosis, and varicella zoster virus infections mainly include an epidermal barrier alteration as well as itch. Mite-bacteria interaction is also involved in scabies and some environmental factors can promote Gram-negative bacterial infections of the feet. Furthermore, the bacterial ecology of these superinfections may depend on the geographical origin of the patients, especially in ectoparasitosis. Bacterial superinfections can also have different clinical aspects depending on the underlying dermatoses. Subsequently, the choice of class, course, and duration of antibiotic treatment depends on the severity of the infection and the suspected bacteria, primarily targeting S. aureus. Prevention of these secondary bacterial infections depends first and foremost on the management of the underlying skin disorder. At the same time, educating the patient on maintaining good skin hygiene and reporting changes in the primary lesions is crucial. In the case of recurrent secondary infections, decolonization of S. aureus is deemed necessary, particularly in atopic dermatitis.

Infective Endocarditis in Pregnancy Diagnosed Early Based on Elevated D-Dimer Levels: A Case Report

We discuss a case where the blood cultures of a patient with clinical chorioamnionitis and elevated D-dimer levels enabled early diagnosis of infective endocarditis. A 31-year-old female with a 39-week pregnancy presented to the obstetrics department with a fever. Cardiotocography revealed fetal tachycardia and severe late deceleration. Preoperative examinations revealed a leukocyte count of 15,900/μL and D-dimer levels of 86.2 μg/mL. She was diagnosed with a non-reassuring fetal status due to clinical chorioamnionitis; accordingly, an emergency cesarean section was performed. Imaging studies ruled out the possibility of a thromboembolism. Subsequent maternal blood cultures were positive for Staphylococcus aureus. Echocardiography revealed vegetation on the aortic valve, leading to a diagnosis of infective endocarditis. Blood cultures can be useful in evaluating for sepsis in cases of clinical chorioamnionitis with elevated D-dimer levels as they may facilitate early diagnosis of infective endocarditis during pregnancy.

Differentiation of keratinocytes or exposure to type 2 cytokines diminishes S. aureus internalization

Staphylococcus aureus is a leading cause of skin and soft tissue infections. Colonization by this bacterium is increased in individuals with chronic cutaneous diseases such as atopic dermatitis, psoriasis, and bullous pemphigoid. The greater abundance of S. aureus on the skin of subjects with atopic dermatitis in particular has been linked to recurrent cutaneous infections. The primary cell type of the epidermal layer of the skin is the keratinocyte, and it is thought that S. aureus internalized in keratinocytes associates with an increased incidence of skin infections. This study addresses whether keratinocyte differentiation and/or inflammation, two important characteristics altered in cutaneous diseases, influence bacterial internalization. To do this, S. aureus internalization was measured in immortalized and primary keratinocytes that were differentiated using high Ca2+-containing media and/or exposed to cytokines characteristic of atopic dermatitis (IL-4 and IL-13) or psoriasis (IL-17A and IL-22) skin. Our results indicate that S. aureus internalization is uniquely decreased upon keratinocyte differentiation, since this was not observed with another skin-resident bacterium, S. epidermidis. Additionally, treatment with IL-4 + IL-13 diminished bacterial internalization. We interpret this decrease as a mechanism of keratinocyte-based bacterial killing since a similar number of bacterial genomes were detected in cytokine-treated cells, but less viable internalized S. aureus was recovered. Finally, of the receptors reported for S. aureus binding/internalizing into keratinocytes, expression of the α5 component of the α5β1 integrin was in greatest accordance with the number of internalized bacteria in the context of keratinocyte differentiation.IMPORTANCEIndividuals with chronic cutaneous diseases demonstrate heightened susceptibility for severe and recurrent infections from Staphylococcus aureus. What drives this altered susceptibility remains poorly understood. Previous publications have detected S. aureus as deep as the dermal layer of skin in subjects with atopic dermatitis, suggesting that the cutaneous environment of this disease enables deeper bacterial infiltration than occurs in healthy individuals. This observation indicates that S. aureus has greater opportunity to interact with multiple skin cell types in individuals with chronic inflammatory skin diseases. Identifying the characteristics of the skin that influence bacterial internalization, a common method to establish reservoirs and evade the immune response, is critical for our understanding of S. aureus pathogenesis. The significance of this research is the novel identification of epidermal characteristics that influence S. aureus internalization. With this knowledge, methods can be developed to identify patient populations at greater risk for cutaneous infections.

Distinct T cell signatures are associated with Staphylococcus aureus skin infection in pediatric atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin condition with a childhood prevalence of up to 25%. Microbial dysbiosis is characteristic of AD, with Staphylococcus aureus the most frequent pathogen associated with disease flares and increasingly implicated in disease pathogenesis. Therapeutics to mitigate the effects of S. aureus have had limited efficacy and S. aureus-associated temporal disease flares are synonymous with AD. An alternative approach is an anti-S. aureus vaccine, tailored to AD. Experimental vaccines have highlighted the importance of T cells in conferring protective anti-S. aureus responses; however, correlates of T cell immunity against S. aureus in AD have not been identified. We identify a systemic and cutaneous immunological signature associated with S. aureus skin infection (ADS.aureus) in a pediatric AD cohort, using a combined Bayesian multinomial analysis. ADS.aureus was most highly associated with elevated cutaneous chemokines IP10 and TARC, which preferentially direct Th1 and Th2 cells to skin. Systemic CD4+ and CD8+ T cells, except for Th2 cells, were suppressed in ADS.aureus, particularly circulating Th1, memory IL-10+ T cells, and skin-homing memory Th17 cells. Systemic γδ T cell expansion in ADS.aureus was also observed. This study suggests that augmentation of protective T cell subsets is a potential therapeutic strategy in the management of S. aureus in AD.

Atopic Dermatitis and the Risk of Infection in End-Stage Renal Disease

Background and Objectives: Atopic dermatitis (AD), also known as eczema, is a common chronic inflammatory skin condition affecting 16.5 million adults in the United States. AD is characterized by an impaired epidermal barrier that can predispose individuals to infection. End-stage renal disease (ESRD) is also commonly complicated by infections due to chronic vascular access and immune-system dysfunction, possibly related to uremia. Multiple studies have reported that renal disease is a common comorbidity in adults with atopic dermatitis. The aim of this study was to determine whether AD is a risk factor for certain infections in patients with ESRD. Materials and Methods: Using the United States Renal Data System, a retrospective cohort analysis was conducted on adult ESRD patients initiating dialysis between 2004 and 2019 to investigate associations between infections and AD in this population. Results: Of 1,526,266 patients, 2290 were identified with AD (0.2%). Infectious outcomes of interest were bacteremia, septicemia, cellulitis, herpes zoster, and conjunctivitis. In all infectious outcomes except for conjunctivitis, patients with the infectious outcomes were more likely to carry a diagnosis of AD. After controlling for demographic and clinical covariates, AD was associated with an increased risk of cellulitis (adjusted relative risk (aRR) = 1.39, 95% confidence interval (CI) = 1.31-1.47) and herpes zoster (aRR = 1.67, CI = 1.44-1.94), but not with bacteremia (aRR = 0.96, CI = 0.89-1.05), septicemia (aRR = 1.02, CI = 0.98-1.08), or conjunctivitis (aRR = 0.97, CI = 0.740-1.34). Conclusions: Overall, after controlling for demographic and clinical covariates and adjusting for person-years-at-risk, AD was associated with an increased risk for some, but not all, infections within the population of patients with ESRD.

Association Between Staphylococcus Aureus Colonization and Pediatric Atopic Dermatitis: A Systematic Review and Meta-Analysis

Background

Atopic dermatitis is a chronic inflammatory skin condition common in early childhood. Acute exacerbation is frequently associated with Staphylococcus aureus colonization.

Aims and Objectives

This study aims to explore the relationship between S. aureus skin and nasal colonization with pediatric atopic dermatitis.

Methods

A systematic review and meta-analysis were conducted by comparing atopic dermatitis patients aged ≤18 years and nondiseased controls. A random-effects model was used to obtain the pooled prevalence and odds ratio of S. aureus colonization at eczematous skin, nonlesional skin, and nasal cavity. Subgroup analyses for colonization with methicillin-resistant S. aureus were also evaluated.

Results

A total of 2,670 cases and 1,224 controls from 26 studies were included in the meta-analysis. S. aureus colonization at eczematous skin and nasal cavity is significantly higher in atopic dermatitis compared to control with odds ratios of 10.55 (95% confidence interval [CI]; 4.85-22.92, P < .001) and 2.38 (nasal cavity; 95% CI; 1.46-3.90, P < .001), respectively. The pooled prevalence of skin and nasal colonization were 55.0% (eczematous skin; 95% CI; 38.3-71.7), 23.3% (nonlesional skin; 95% CI; 12.6-33.9), and 56.3% (95% CI; 43.2-69.4), respectively. Methicillin-resistant S. aureus strain was obtained from the nares and eczematous skin with rates of 11.6% (95% CI; 6.5-16.7) and 8.5% (95% CI; 4.3-12.8), respectively.

Conclusion

Children with atopic dermatitis are more prone to skin and nasal colonization by S. aureus compared to nondiseased individuals.

Association between poly-sensitisation and sensitisation to staphylococcal enterotoxin A and B affecting allergic severity in children

PURPOSE

Accumulating evidence suggests that Staphylococcus aureus plays a significant role as a disease modifier in upper and lower airway diseases. We aimed to assess the association between staphylococcal enterotoxins (SEs) with allergic diseases and the degree of allergen sensitisation in children, which remains unclear.

METHODS

We retrospectively reviewed the medical records of 455 patients aged 3-18 years between March 2018 and March 2022. Clinical history and demographic data were obtained. The baseline study included paranasal sinus X-ray scan, multiple allergen simultaneous test, and ImmunoCAP® for measuring serum total and specific immunoglobulin E (IgE) levels to allergens and staphylococcal enterotoxin A and B (SEA and SEB).

RESULTS

The mean age was 9.77 ± 4.3 years. 133 patients (29.2%) were sensitised to one inhalant allergen, and 188 patients (41.3%) showed polysensitisation. Patients sensitised to SEs showed higher total and specific IgE levels and total eosinophil counts compared to non-SE-sensitised patients. Sensitisation to SEs is closely associated with polysensitisation to inhalant allergens and allergic multimorbidity. When the SE-IgE value was 0.35 or higher, the odds ratio for allergen polysensitisation was significantly higher than when the SE-IgE value was lower than 0.35.

CONCLUSIONS

Association between polysensitisation and sensitisation to SEs in children shows the higher the specific IgE levels for SEs, the higher the likelihood of polysensitisation. Considering the relationship between polysensitisation, high IgE levels, and the severity of allergic morbidity, sensitisation to SEs is thought to be related to allergy severity.

Bloodstream Infection in Children With Epidermolysis Bullosa

BACKGROUND

Epidermolysis bullosa (EB) is frequently complicated by skin infection, which can lead to bacteremia. However, bloodstream infections (BSI) in patients with EB have not been well described.

METHODS

Retrospective study of BSI in children 0-18 years with EB from a national reference unit in Spain, in 2015-2020.

RESULTS

Among 126 children with EB, we identified 37 BSI episodes in 15 patients (14 recessive dystrophic EB, 1 junctional EB). The most frequent microorganisms were Pseudomonas aeruginosa (n = 12) and Staphylococcus aureus (n = 11). Five P. aeruginosa isolates were ceftazidime-resistant (42%), 4 of which were also resistant to meropenem and quinolones (33%). As for S. aureus, 4 (36%) were methicillin-resistant and 3 (27%) clindamycin-resistant. In 25 (68%) BSI episodes skin cultures had been performed in the previous 2 months. The most frequent isolates were also P. aeruginosa (n = 15) and S. aureus (n = 11). In 13 cases (52%), smear and blood cultures grew the same microorganism, with the same antimicrobial resistance pattern in 9 isolates. Twelve patients (10%) died during follow-up (9 RDEB and 3 JEB). BSI was the cause of death in 1 case. In patients with severe RDEB, a history of BSI was associated with higher mortality (OR 6.1, 95% CI: 1.33-27.83, P = 0.0197).

CONCLUSIONS

BSI is an important cause of morbidity in children with severe forms of EB. The most frequent microorganisms are P. aeruginosa and S. aureus, with high rates of antimicrobial resistance. Skin cultures can help guide treatment decisions in patients with EB and sepsis.

Topical niclosamide (ATx201) reduces Staphylococcus aureus colonization and increases Shannon diversity of the skin microbiome in atopic dermatitis patients in a randomized, double-blind, placebo-controlled Phase 2 trial

Background

In patients with atopic dermatitis (AD), Staphylococcus aureus frequently colonizes lesions and is hypothesized to be linked to disease severity and progression. Treatments that reduce S. aureus colonization without significantly affecting the skin commensal microbiota are needed.

Methods and findings

In this study, we tested ATx201 (niclosamide), a small molecule, on its efficacy to reduce S. aureus and propensity to evolve resistance in vitro. Various cutaneous formulations were then tested in a superficial skin infection model. Finally, a Phase 2 randomized, double‐blind and placebo‐controlled trial was performed to investigate the impact of ATx201 OINTMENT 2% on S. aureus colonization and skin microbiome composition in patients with mild‐to‐severe AD (EudraCT:2016‐003501‐33). ATx201 has a narrow minimal inhibitory concentration distribution (.125–.5 μg/ml) consistent with its mode of action – targeting the proton motive force effectively stopping cell growth. In murine models, ATx201 can effectively treat superficial skin infections of methicillin‐resistant S. aureus. In a Phase 2 trial in patients with mild‐to‐severe AD (N = 36), twice‐daily treatment with ATx201 OINTMENT 2% effectively reduces S. aureus colonization in quantitative colony forming unit (CFU) analysis (primary endpoint: 94.4% active vs. 38.9% vehicle success rate, p = .0016) and increases the Shannon diversity of the skin microbiome at day 7 significantly compared to vehicle.

Conclusion

These results suggest that ATx201 could become a new treatment modality as a decolonizing agent.

Microbiologic characterisation of bacterial infections in children with atopic dermatitis

Background: Patients with atopic dermatitis (AD), the commonest chronic inflammatory skin disease are often colonised and infected by Staphylococcus aureus. In this study, we aimed to determine the type and antibacterial sensitivities of the bacteria infecting eczematous lesions in children with AD and to recommend first-line antibiotic therapy.Methods: A prospective study was conducted from June 2020 to June 2021 in children with AD presenting with a cutaneous infection at the King Edward hospital VIII outpatient dermatology clinic. Swabs were collected for microbial culture, confirming infections and assessing antibiotic sensitivity for infected sites.Results: Ninety six children were recruited during the study period with a mean age of 4.3 ± 3.4 years. The commonest cause of bacterial infection was Staphylococcus aureus seen in 74 (77.1%) cases, followed by Staphylococcus aureus and Group A β-haemolytic streptococcus (GAS) co-infection in 22 (22.9%) cases. The majority of these infections were observed on the lower limbs in 50 (52.08%) cases and in moderate 37 (38.5%) cases and severe eczema cases of 38 (39.6%) in AD. There was no gender predilection. Staphylococcus aureus was sensitive to amoxicillin-clavulanic acid in 57 (77.0%) cases, cloxacillin in 53 (71.6%) cases and clindamycin in 24 (32.4%) cases, whereas GAS was mostly sensitive to ampicillin in 10 (45.5%) cases. No swabs retained a resistant strain.Conclusion: Staphylococcus aureus is the commonest bacterial cause of cutaneous infection in children with AD in our setting. Amoxicillin-clavulanic acid and cloxacillin remain the most sensitive therapeutic options for this infection, however, a larger study is required to explore resistance strains, if any, in our setting.

Septic Arthritis in Paediatric Patients: A 10-year Experience at a Single Institution

Background

We evaluated the clinical presentation and microbiological profile of a cohort of paediatric patients with septic arthritis at a tertiary institution in Singapore.

Methods

After obtaining institutional board approval, records of all patients below 18 years presenting with septic arthritis between 2010 and 2019 were reviewed. Patient demographic and medical data were analysed.

Results

Of 24 patients with 26 infected joints with a mean age of 7.1 years, 50.0% had pre-existing atopic dermatitis. The most common site infected was the hip ( n = 11, 42.3%). The most common pathogen isolated from tissue cultures was methicillin-sensitive-Staphylococcus aureus (MSSA) ( n = 9, 37.5%). Twenty-three (95.8%) of the patients underwent surgical drainage.

Conclusions

The skin of patients with atopic dermatitis has been shown to be more frequently colonised with Staphylococcus aureus compared to healthy individuals. The prevalence of atopic dermatitis in our cohort was higher compared to the reported national average of 20.8%. MSSA was the most commonly reported pathogen, and the hip joint most commonly affected. Less than half of the cohort had positive tissue or blood cultures. In paediatric patients with known atopic dermatitis who present with a fever, a painful joint and limited range of motion, septic arthritis should be considered and early drainage and antibiotics instituted.

Colonization With Staphylococcus aureus in Atopic Dermatitis Patients: Attempts to Reveal the Unknown

Atopic dermatitis (AD) patients are massively colonized with Staphylococcus aureus (S. aureus) in lesional and non-lesional skin. A skin infection may become systemic if left untreated. Of interest, the incidence of multi-drug resistant S. aureus (MRSA) in AD patients is higher as compared to a healthy population, which makes treatment even more challenging. Information on the specific genetic background of S. aureus accompanying and/or causing AD flares would be of great importance in terms of possible treatment option development. In this review, we summarized the data on the prevalence of S. aureus in general in AD skin, and the prevalence of specific clones that might be associated with flares of eczema. We put our special interest in the presence and role of staphylococcal enterotoxins as important virulence factors in the epidemiology of AD-derived S. aureus. Also, we summarize the present and potentially useful future anti-staphylococcal treatment.

Role of Antimicrobial Peptides in Skin Barrier Repair in Individuals with Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that exhibits a complex interplay of skin barrier disruption and immune dysregulation. Patients with AD are susceptible to cutaneous infections that may progress to complications, including staphylococcal septicemia. Although most studies have focused on filaggrin mutations, the physical barrier and antimicrobial barrier also play critical roles in the pathogenesis of AD. Within the physical barrier, the stratum corneum and tight junctions play the most important roles. The tight junction barrier is involved in the pathogenesis of AD, as structural and functional defects in tight junctions not only disrupt the physical barrier but also contribute to immunological impairments. Furthermore, antimicrobial peptides, such as LL-37, human b-defensins, and S100A7, improve tight junction barrier function. Recent studies elucidating the pathogenesis of AD have led to the development of barrier repair therapy for skin barrier defects in patients with this disease. This review analyzes the association between skin barrier disruption in patients with AD and antimicrobial peptides to determine the effect of these peptides on skin barrier repair and to consider employing antimicrobial peptides in barrier repair strategies as an additional approach for AD management.

Risk of systemic infections in adults with atopic dermatitis: A nationwide cohort study

BACKGROUND

Atopic dermatitis (AD) has been linked to systemic infections in adulthood, but large-scale studies are few, and potential associations are unclear.

OBJECTIVE

To examine whether adults with AD have increased risk of developing systemic infections leading to hospital-based management.

METHODS

Nationwide register-based cohort study including all Danish adults from 1995 through 2017. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated by using Cox models.

RESULTS

A total of 10,602 adults with AD (median age, 29.8 y; interquartile range, 22.6-44.8) and 106,020 reference individuals were included. The overall incidence rate per 10,000 person-years of systemic infections was 180.6 (95% CI, 172.6-189.0) among adults with AD compared with 120.4 (95% CI, 118.3-122.5) among reference adults. The association between AD and systemic infections was observed for musculoskeletal (adjusted HR [aHR], 1.81; 95% CI, 1.42-2.31), heart (aHR, 1.75; 95% CI, 1.21-2.53), and upper (aHR, 1.42; 95% CI, 1.15-1.73) and lower respiratory tract infections (aHR, 1.21; 95% CI, 1.10-1.33). The risk of sepsis (aHR, 1.19; 95% CI, 1.01-1.44) and skin infections (aHR, 2.30; 95% CI, 2.01-2.62) was also increased.

LIMITATIONS

The findings cannot be generalized to adults with milder AD seen outside the hospital system.

CONCLUSION

We found an increased risk of systemic infections among adults with hospital managed AD.

Pseudoaneurysm rupture presenting as bleeding from the cannulation site in a paediatric patient with dilated cardiomyopathy and congenital skin lesions requiring EXCOR® Paediatric ventricular assist device: a case report

Background

EXCOR^® Paediatric is used worldwide as a bridge-to-transplant treatment. It provides improved patient stability during the waiting period compared with previous ventricular assist device (VAD). However, investigations into complications which may occur among the paediatric population during long waiting periods are still sparse.

Case summary

We describe the case of a 7-year-old girl who presented with severe heart failure due to dilated cardiomyopathy. She also had a skin lesion which appeared soon after birth. She had received an EXCOR^® implant and was waiting for heart transplant. Her skin lesion worsened after implantation and she suffered recurrent infections. Multiple bleeding episodes from the cannulation site occurred; therefore, surgical exploration of the bleeding was performed. She passed away during the procedure due to massive bleeding caused by rupture of a pseudoaneurysm caused by blood-stream infection.

Discussion

Patients with skin disease may be at increased risk of infection when on a VAD. Infections that occur during VAD therapy may cause serious complications such as pseudoaneurysm. The possibility of pseudoaneurysm should be considered when bleeding occurs in a patient on VAD.

Osteomyelitis complicating secondarily infected atopic eczema: two case reports and a narrative literature review

BACKGROUND

Atopic eczema is a relapsing, itchy chronic cutaneous inflammatory disease that commonly affects children. The disease is often complicated by cutaneous infections such as eczema herpeticum, eczema vaccinatum and a varied number of bacterial infections - impetigo, cellulitis and erysipelas. However, rare case reports of infective endocarditis, otitis media and osteo-articular infections have been associated with atopic eczema. These associations possibly represent the extracutaneous infectious complications of atopic eczema.

CASE PRESENTATION

Here we present two cases of osteomyelitis in HIV negative children with habitual scratching of poorly managed and/or uncontrolled atopic eczema respectively. Both cases presented to the orthopaedic surgeons and were admitted as acute phalangeal osteomyelitis and acute - on - chronic tibial osteomyelitis respectively. The first case was an 8 year old girl who had moderate-severe poorly-controlled atopic eczema and contiguously spread phalangeal osteomyelitis. The second case was an 11 year old pre-pubertal boy who had untreated atopic eczema and tibial osteomyelitis possibly from haematogenously spread Staphylococcus aureus infection. Both were successfully discharged from hospital and currently have well controlled eczema. The 11 year old patient is also being reviewed monthly by the orthopaedic surgeons and is chronic suppressive antibiotics. He may require sequestrectomy, should it be needed.

CONCLUSIONS

Invasive staphylococcal and streptococcal osteo-articular (OA) infection can arise as an extra-cutaneous infectious complication of poorly controlled atopic eczema. It is more common in the 3 to 15 year age group and especially in boys with a septic arthritis to osteomyelitis ratio of around 29:5. Clinicians should maintain a high index of suspicion in patients with moderate-severe atopic eczema and they ought to promptly manage these OA infections with intravenous antibiotics to avoid further complications.

The role of bacterial skin infections in atopic dermatitis: expert statement and review from the International Eczema Council Skin Infection Group

Patients with atopic dermatitis (AD) have an increased risk of bacterial skin infections, which cause significant morbidity and, if untreated, may become systemic. Staphylococcus aureus colonizes the skin of most patients with AD and is the most common organism to cause infections. Overt bacterial infection is easily recognized by the appearance of weeping lesions, honey‐coloured crusts and pustules. However, the wide variability in clinical presentation of bacterial infection in AD and the inherent features of AD – cutaneous erythema and warmth, oozing associated with oedema, and regional lymphadenopathy – overlap with those of infection, making clinical diagnosis challenging. Furthermore, some features may be masked because of anatomical site‐ and skin‐type‐specific features, and the high frequency of S. aureus colonization in AD makes positive skin swab culture of suspected infection unreliable as a diagnostic tool. The host mechanisms and microbial virulence factors that underlie S. aureus colonization and infection in AD are incompletely understood. The aim of this article is to present the latest evidence from animal and human studies, including recent microbiome research, to define the clinical features of bacterial infections in AD, and to summarize our current understanding of the host and bacterial factors that influence microbial colonization and virulence.

Two Cases of Infective Endocarditis in Patients with Atopic Dermatitis

Patients with atopic dermatitis have high rates of skin surface colonization of Staphylococcus aureus. At the same time, S. aureus is the major causative organism in infective endocarditis, approximately accounting for 30%~50% cases of infective endocarditis. A 22-year-old male with severe atopic dermatitis presented with fever and myalgia. He was diagnosed with active infective endocarditis causing multiple cerebral infarction, splenic infarction, and septic shoulder requiring synovectomy. Blood culture proved methicillinsensitive Staphylococcus aureus bacteremia, and the culture from the skin revealed same bacteria. After treated with intravenous antibiotics for 6 weeks, patient was improved. Another 42-year-old female with severe atopic dermatitis who presented with fever and chilling was hospitalized due to acute infective endocarditis. She also had left flank pain and visual disturbance, due to splenic infarction and acute cerebral infarction, respectively. As blood culture revealed methicillin-sensitive Staphylococcus aureus bacteremia, she treated with intravenous antibiotics for 6 weeks. The route of entry of two patients was attributed to the patient eczematous scratching lesion of poorly controlled atopic dermatitis. Infective endocarditis can result in the context of acute deterioration of atopic dermatitis. Dermatologists need to pay attention to this risk and actively manage such conditions in order to decrease the risk of infective endocarditis arising from skin lesions in atopic patients. For these reasons, we herein report two cases of infective endocarditis in patients with atopic dermatitis.

Methicillin-sensible Staphylococcus aureus causing endocarditis, with cerebral and orthopaedic complications, in a 17-month-old child with no risk factor

We report a case of Staphylococcus aureus endocarditis, with large vegetation, in a 17-month-old male infant, complicated with meningitis, ischaemic strokes and osteoarthritis leading to haemorrhagic stroke by aneurysm rupture. He did not present any risk factor for endocarditis. The final course was favourable through, after valve replacement. The strain was sensible to methicillin and belongs to complex clonal 398, with accessory gene regulator I. We did not found immunodeficiency.

Atopic dermatitis: the skin barrier and beyond

BACKGROUND

Atopic dermatitis is the most common chronic inflammatory skin disorder, affecting up to 20% of children and 10% of adults in industrialized countries. This highly debilitating condition poses a considerable burden to both the individual and society at large. The pathophysiology of atopic dermatitis is complex, encompassing both genetic and environmental risk factors.

METHODS

This is a narrative review based on a systematic literature search.

CONCLUSIONS

Dysregulation of innate and adaptive immunity plays a key role; however, recent epidemiological, genetic and molecular research has focused interest on skin barrier dysfunction as a common precursor and pathological feature. Current understanding of the aetiology of atopic dermatitis highlights disruption of the epidermal barrier leading to increased permeability of the epidermis, pathological inflammation in the skin, and percutaneous sensitization to allergens. Thus, most novel treatment strategies seek to target specific aspects of the skin barrier or cutaneous inflammation. Several studies have also shown promise in preventing atopic dermatitis, such as the early use of emollients in high-risk infants. This may have broader implications in terms of halting the progression to atopic comorbidities including food allergy, hay fever and asthma.

Infective Endocarditis Associated with Atopic Dermatitis

We report a case of aortic valve infective endocarditis (IE) in a 24-year-old man with atopic dermatitis (AD). He had a history of balloon valvuloplasty for a stenotic bicuspid aortic valve, and had dental caries but no invasive dental procedure before the onset of IE. On admission, skin lesions of AD with itching and scratches were found on the neck, trunk, and extremities. Echocardiography showed a vegetation on the aortic valve with mild steno-regurgitation, but extension of IE to the annulus was not detected. Magnetic resonance imaging identified fresh cerebral infarction without neurological dysfunction, leading us to suspect an embolism. Blood cultures grew methicillin-sensitive Staphylococcus aureus. During emergency surgery, a vegetation attached to the conjoined cusp was observed, and the aortic valve was replaced with a mechanical valve. The patient recovered uneventfully without any complications such as recurrent IE or mediastinitis. We also review previously reported cases of IE associated with AD.

Staphylococcus aureus infections, some second thoughts

PURPOSE OF REVIEW

Staphylococcus aureus (S. aureus) is well known for its ability to cause life-threatening infections. On the other hand, this bacterium can thrive as a commensal on and in human tissues without causing much problems. How big a threat is S. aureus actually? Furthermore, commensalism is associated with biofilms, where can we find them, and which natural and artificial components activate biofilm formation?

RECENT FINDINGS

Recent findings on S. aureus carriage on skin, mucosa, and in wounds indicate the presence of large numbers of S. aureus, yet its abundance can be without major implications for the host. S. aureus is often present in biofilms, together with other microorganisms, which can stimulate biofilm formation of S. aureus, in addition medicine including antibiotics can do the same.

SUMMARY

S. aureus can cause devastating infections, but when we take into consideration the ubiquitous presence of S. aureus, the risk seems to be relatively low. S. aureus forms biofilms in response to the 'hazards' on the human body, and signal to do so can come from various sources. All this has to be taken into consideration when we treat a patient as this might have enormous impact on the outcome.

Infectious Complications in Atopic Dermatitis

Atopic dermatitis is characterized by the interplay of skin barrier defects with the immune system and skin microbiome that causes patients to be at risk for infectious complications. This article reviews the pathogenesis of atopic dermatitis and the mechanisms through which patients are at risk for infection from bacterial, viral, and fungal pathogens. Although these complications may be managed acutely, prevention of secondary infections depends on a multipronged approach in the maintenance of skin integrity, control of flares, and microbial pathogens.

Systemic immune mechanisms in atopic dermatitis and psoriasis with implications for treatment

Atopic dermatitis (AD) and psoriasis are inflammatory skin diseases that negatively affect patients' quality of life. Although distinctions exist between these diseases, both are characterized by erythematous, thickened epidermal lesions that vary in intensity and affected body surface area. Early models of aetiology attributed symptoms of both diseases to cutaneous inflammation at lesion sites, but recent studies have established that activated immune mediators in the circulation drive disease severity. Activation of T helper 2 (Th2) and Th22 cells in the circulation appears to be the principal initiator of acute AD pathology, with the emergence of Th1 and Th17/interleukin (IL)-23 pathway activation marking the transition to a chronic state. The Th17/IL-23 pathway also has an important role in psoriasis. The role of systemic inflammation in AD and psoriasis is supported by the occurrence of non-cutaneous comorbidities that affect patients, most of which intensify morbidity and disability associated with lesional skin. Atopic dermatitis is associated with allergic disorders consisting of the "atopic march," whereas psoriasis is frequently accompanied by psoriatic arthritis. Patients with both disorders are at significantly higher risk of obesity, metabolic disorders, and cardiovascular diseases, all of which feature inflammatory components in their pathology models. These insights have led to novel therapeutics aimed at addressing psoriasis by targeting tumor necrosis factor- and Th17-related cytokine pathways. The success of these agents in psoriasis management is driving new therapeutic approaches for moderate-to-severe AD, including agents targeting the Th2 and Th17/Th22 cytokine pathways.

Increasing Comorbidities Suggest that Atopic Dermatitis Is a Systemic Disorder

Atopic dermatitis comorbidities extend well beyond the march to allergic conditions (food allergy, asthma, allergic rhinitis, allergic conjunctivitis, and eosinophilic esophagitis), suggesting both cutaneous and systemic immune activation. In reviewing atopic dermatitis comorbidities, Councilors of the International Eczema Council found a strong pattern of immune activation in peripheral blood and the propensity to both skin and systemic infections. Associations with cardiovascular, neuropsychiatric, and malignant diseases were increasingly reported, but confirmation of their link with atopic dermatitis requires longitudinal studies. Given the possibility of atopic dermatitis-related systemic immune activation, future investigations of new interventions should concurrently examine the impact on these comorbidities.