Children with atopic dermatitis appear less likely to be infected with community acquired methicillin-resistant Staphylococcus aureus: the San Diego experience

Global Antimicrobial Susceptibility Patterns of Staphylococcus aureus in Atopic Dermatitis: A Systematic Review and Meta-Analysis

Importance

Individuals with atopic dermatitis are frequently colonized and infected with Staphylococcus aureus. Empirical antibiotic therapy for individuals with atopic dermatitis is common, but data about the antimicrobial susceptibility profiles of S aureus strains isolated from these individuals are scarce for those living in particular geographic areas.

Objective

To determine the antimicrobial susceptibility of S aureus from individuals with atopic dermatitis and analyze differences according to the income level of the country of origin and the data collection period.

Data Sources

A meta-analysis of the literature was performed from the inception of the included databases (MEDLINE, Embase, Web of Science, Scopus, and Cochrane) to June 20, 2023, using predetermined Medical Subject Headings.

Study Selection

Studies were included if they reported antibiotic susceptibility profiles of 1 or more S aureus cutaneous isolates from individuals with atopic dermatitis. Articles written in English, Spanish, French, or German were included.

Data Extraction and Synthesis

Working in pairs, 6 of the authors conducted the data extraction. The guidelines from the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) were followed.

Main Outcomes and Measures

The outcome of interest was antimicrobial susceptibility.

Results

A total of 61 studies reported 4091 S aureus isolates from individuals with atopic dermatitis. For 4 of the 11 commonly used antibiotics (36.4%), antimicrobial susceptibility was 85% or less, including for methicillin (binomial proportion, 0.85 [95% CI, 0.76-0.91]), erythromycin (binomial proportion, 0.73 [95% CI, 0.61-0.83]), fusidic acid (binomial proportion, 0.80 [95% CI, 0.62-0.91]), and clindamycin (binomial proportion, 0.79 [95% CI, 0.65-0.89]). Most studies (46; 75.4%) were conducted in high-income countries. Antimicrobial susceptibility to erythromycin, methicillin, and trimethoprim and sulfamethoxazole was significantly lower in lower middle-income countries and upper middle-income countries. Regarding the temporal trends, 33 studies (54.1%) reported data collected from 1998 to 2010. Antimicrobial susceptibility patterns have not changed over time.

Conclusions and Relevance

In this systematic review and meta-analysis, antimicrobial susceptibility of S aureus to β-lactams, erythromycin, clindamycin, and fusidic acid may be suboptimal for empirical use in individuals with atopic dermatitis. Significant differences in antimicrobial susceptibility patterns were found in high-income countries and in lower middle-income countries and upper middle-income countries for some antibiotics.

Methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolates from skin and nares of Brazilian children with atopic dermatitis demonstrate high level of clonal diversity

BACKGROUND

Atopic dermatitis (AD) primarily affects the pediatric population, which is highly colonized by S. aureus. However, little is known about the genetic features of this microorganism and other staphylococcal species that colonize AD patients.

OBJECTIVE

This study aimed to characterize Staphylococcus spp. isolated from the nares and skin (with and without lesion) of 30 AD and 12 non-AD Brazilian children.

METHODS

Skin and nasal swabs were cultured onto mannitol salt agar, and bacterial colonies were counted and identified by matrix assisted laser desorption ionization time of flight mass spectrometry and polymerase chain reaction (PCR). Antimicrobial susceptibility was evaluated by phenotypic and genotypic tests. In S. aureus isolates, Panton-Valentine leukocidin genes were detected by PCR, and their clonality was assessed by pulsed-field gel electrophoresis and multilocus sequence typing.

RESULTS

S. aureus was more prevalent in the nares (P = 0.005) and lesional skin (P = 0.0002) of children with AD, while S. hominis was more frequent in the skin of non-AD children (P < 0.0001). All children in the study, except one from each group, were colonized by methicillin-resistant coagulase-negative Staphylococcus and 24% by methicillin-resistant S. aureus. Despite the great clonal diversity of S. aureus (18 sequence types identified), most AD children (74.1%) were colonized by the same genotype in both niches.

CONCLUSION

High colonization by polyclonal S. aureus isolates was found among children with AD, while S. hominis was more frequent among non-AD children. The high prevalence of methicillin-resistant staphylococcal isolates highlights the importance of continued surveillance, especially when considering empiric antibiotic therapy for the treatment of skin infections in these patients.

Real-world comorbidities of atopic dermatitis in the pediatric ambulatory population in the United States

BACKGROUND

Increasing evidence has suggested the systemic nature of atopic dermatitis (AD), a common inflammatory skin condition in children. However, comprehensive analyses of real-world comorbidities in pediatric AD are limited.

OBJECTIVE

To characterize comorbidity burden in patients with AD aged <18 years old.

METHODS

The MarketScan commercial claims database was queried from January 1, 2017, to December 31, 2017. Age- and sex-matched analyses were used to compare patients with AD with general population controls.

RESULTS

A total of 86,969 pediatric patients with AD and 116,564 matched controls were identified. Increased anxiety (odds ratio [OR], 1.20) and attention-deficit hyperactivity disorder (OR, 1.11) were noted in patients with AD. In addition to dermatologic/allergic diseases, AD was also associated with infections, including methicillin-resistant Staphylococcus aureus (OR, 3.76), and autoimmune conditions, including vitiligo (OR, 2.98) and alopecia areata (OR, 4.32). Pediatric patients with AD had higher likelihoods of lymphoid/hematologic malignancies (OR, 1.94), ocular disorders (OR, 1.37-2.02), metabolic syndrome (OR, 1.61), and obesity (OR, 1.81). For all the ORs mentioned above, P was <.001.

LIMITATIONS

Retrospective analysis of health care claims data.

CONCLUSIONS

AD in pediatric patients was associated with a wide range of psychologic and systemic comorbidities. Increased awareness can help minimize its negative effects on the quality of life and prevent long-term health consequences in young patients with AD.

Methicillin-resistant Staphylococcus aureus from infected skin lesions present several virulence genes and are associated with the CC30 in Brazilian children with atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease and colonization by Staphylococcus aureus may affect up to 100% of these patients. Virulent and resistant isolates can worsen AD patient clinical condition and jeopardize the treatment. We aimed to detect virulence genes and to evaluate the biofilm production of S. aureus isolates from infected skin lesions of children with AD. Methicillin resistance was detected by phenotypic and molecular tests and the virulence genes were detected by PCR. Biofilm formation was assessed by bacterial growing on microtiter plates and later stained with safranin. Genotyping was performed by Pulsed-Field Gel Electrophoresis and Multilocus Sequence Typing. Among 106 AD patients, 55 (51.8%) had developed S. aureus cutaneous infections and 23 (41.6%) were methicillin-resistant (MRSA). All 55 isolates carried the fnbA, hla, icaA, sasG, and seu genes, and more than 70% presented cna, eap, ebpS, hlg, and pvl genes. Clonal complex (CC) 30 was the main lineage found (34.5%), especially among MRSA isolates (52.2%). The egc cluster and the bbp gene were significantly the most frequent in MRSA isolates and in USA1100/ST30/CC30 lineage. Most of the isolates (74.5%) were non-biofilm producers and many of them only started to produce it in the presence of fibrinogen. There was no significant association between S. aureus isolates features and the AD severity. This study demonstrated a high frequency of CC30 MRSA isolates presenting several virulence genes in infected skin lesions of AD children in Brazil, that may influence the severity of the disease and the treatments required.

Frequency and Clinical Features Associated With Eczema Herpeticum in Hospitalized Children With Presumed Atopic Dermatitis Skin Infection

BACKGROUND

Atopic dermatitis (AD) predisposes to viral skin infections, such as eczema herpeticum (EH), and to bacterial skin infections, such as those caused by Staphylococcus aureus (SA) and group A streptococcus (GAS). This study evaluated clinical features of EH and its frequency of codetection with SA or GAS in children hospitalized for presumed AD skin infection.

METHODS

We retrospectively reviewed clinical data for children ≤18 years of age admitted to a large hospital system for AD with presumed skin infection from January 2004 to December 2018. Those with an alternate primary diagnosis or missing microbiologic data were excluded. Encounters with herpes simplex virus testing were identified as AD with EH (ADEH+) or without (ADEH-). Encounters with bacterial skin culture growth were identified as SA or GAS.

RESULTS

Among 180 AD encounters with suspected skin infection, 133 (74%) were tested for herpes simplex virus. Clinical findings associated with ADEH+ status (n = 61) included fever on admission (59% vs. 32% in ADEH-; P = 0.002), rash on the neck (30% vs. 13%; P = 0.015) and vesicular rash (70% vs. 49%; P = 0.011). Encounters in the ADEH+ group had a longer hospital length of stay compared with encounters in the ADEH- group [median 4 days (interquartile range 3-5 days) vs. 3 days (interquartile range 2-3 days); P < 0.001]. GAS was identified in only 1 ADEH+ encounter (2%) versus 15 ADEH- encounters (26%), P < 0.001.

CONCLUSIONS

Providers should maintain a high index of suspicion for EH in children admitted for presumed AD skin infection. GAS was more commonly associated with ADEH- encounters.

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.

Staphylococcus aureus antibiotic susceptibility patterns in pediatric atopic dermatitis

BACKGROUND/OBJECTIVES

Staphylococcus aureus is the most prevalent bacterial pathogen in atopic dermatitis (AD) patients presenting with skin infections. Despite the known association between S aureus and AD, guidance on empiric antibiotics for skin infections in pediatric AD patients is limited.

METHODS

We conducted a retrospective study over a five-year period to characterize the S aureus strains recovered from pediatric AD patients with clinically apparent bacterial skin infections treated in an academic medical center. We assessed patient demographics and dilute bleach bath usage to determine whether these factors were correlated with methicillin resistance. Culture results from our AD cohort were also compared to those from pediatric patients presenting to the Saint Louis Children's Hospital emergency department (ED) with S aureus skin abscesses from 2013 to 2015.

RESULTS

Methicillin-sensitive S aureus (MSSA) was more prevalent (77.8%) than methicillin-resistant S aureus (MRSA) (22.2%). There was no correlation between MRSA and age, sex, race, or dilute bleach bath use. In comparison with pediatric patients presenting to the ED, AD patients had lower rates of MSSA susceptibility to doxycycline and MRSA susceptibility to trimethoprim-sulfamethoxazole (TMP-SMX).

CONCLUSIONS

First-generation cephalosporins remain appropriate empiric therapy for most pediatric AD patients. In patients with a history of MRSA, empiric doxycycline or TMP-SMX could be considered, given their high MRSA susceptibility rates.

Antibiotic choice and methicillin-resistant Staphylococcus aureus rate in children hospitalized for atopic dermatitis

BACKGROUND

Systemic antibiotics are commonly used in hospitalized patients with severe atopic dermatitis (AD) exacerbation. However, the antibiotic prescribing patterns are unclear.

OBJECTIVE

To compare the prescribing patterns of antibiotics for children who were hospitalized for AD exacerbation and infectious complications.

METHODS

Electronic medical records were reviewed for patients younger than 18 years who were hospitalized for AD exacerbation or infectious complications based on International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification codes from 2003 to 2018. The following information was obtained: history, physical examination findings, physician discharge summary, antibiotic treatments, serum tests, and wound cultures. The t test was used to compare clinical and laboratory features.

RESULTS

A total of 174 patients with AD were included. Seventy patients had AD exacerbation and 104 had infectious complications, including cellulitis, abscesses, invasive infections, and eczema herpeticum. The differences between these 2 groups of patients were further verified by length of stay, serum total IgE level, and inflammatory markers (C-reactive protein and erythrocyte sedimentation rate). A total of 56 of 70 patients (80%) with AD exacerbation were treated with a systemic antibiotic. Clindamycin and vancomycin together accounted for 88% of antibiotics on admission for both groups, whereas clindamycin and sulfamethoxazole-trimethoprim were prescribed at similar rates for both groups at discharge. Wound culture results showed that the methicillin-resistant Staphylococcus aureus (MRSA) rate was significantly lower in children with AD exacerbation (22%) vs infectious complications (39%).

CONCLUSION

Children were treated with a high frequency of anti-MRSA antibiotics for inpatient AD exacerbation and infectious complications. However, the rate of MRSA was significantly lower in children with AD exacerbation. Thus, empiric antibiotic choice for infectious complications may not be appropriate for AD exacerbation.

Major Comorbidities of Atopic Dermatitis: Beyond Allergic Disorders

The consequences of atopic dermatitis reach beyond the skin and past childhood. Patients with atopic dermatitis are at risk of developing allergic comorbidities, but less is known about the associations between atopic dermatitis and non-allergic conditions. Understanding these non-allergic comorbidities has the potential to improve patient outcomes and to help mitigate the cost and burdens associated with these conditions. Atopic dermatitis is associated with cutaneous bacterial infections, more severe forms/courses of cutaneous viral infections, and extra-cutaneous infections. Atopic dermatitis is also associated with several mental health comorbidities particularly attention-deficit hyperactivity disorder, anxiety, and depression. Data are largely inconsistent for specific cancers, but atopic dermatitis appears to protect against malignancy overall; severe long-term atopic dermatitis is associated with adult lymphomas. Atopic dermatitis may also be associated with obesity, cardiovascular disease, and autoimmune disease, particularly alopecia areata and gastrointestinal immune-mediated disorders. Although the causative mechanisms underlying these associations are poorly understood, treating physicians should be aware of associations in seeking to alleviate the burden for patients with atopic dermatitis.

Consensus-based European guidelines for treatment of atopic eczema (atopic dermatitis) in adults and children: part II

This guideline was developed as a joint interdisciplinary European project, including physicians from all relevant disciplines as well as patients. It is a consensus-based guideline, taking available evidence from other guidelines, systematic reviews and published studies into account. This second part of the guideline covers antimicrobial therapy, systemic treatment, allergen-specific immunotherapy, complementary medicine, psychosomatic counselling and educational interventions, whereas the first part covers methods, patient perspective, general measures and avoidance strategies, basic emollient treatment and bathing, dietary intervention, topical anti-inflammatory therapy, phototherapy and antipruritic therapy. Management of AE must consider the individual clinical variability of the disease. Systemic immunosuppressive treatment with cyclosporine, methotrexate, azathioprine and mycophenolic acid is established option for severe refractory cases, and widely available. Biologicals targeting the T helper 2 pathway such as dupilumab may be a safe and effective, disease-modifying alternative when available. Oral drugs such as JAK inhibitors and histamine 4 receptor antagonists are in development. Microbial colonization and superinfection may cause disease exacerbation and can require additional antimicrobial treatment. Allergen-specific immunotherapy with aeroallergens may be considered in selected cases. Psychosomatic counselling is recommended especially in stress-induced exacerbations. Therapeutic patient education ('Eczema school') is recommended for children and adult patients. General measures, basic emollient treatment, bathing, dietary intervention, topical anti-inflammatory therapy, phototherapy and antipruritic therapy have been addressed in the first part of the guideline.

Decolonization of Staphylococcus aureus in patients with atopic dermatitis: a reason for increasing resistance to antibiotics?

INTRODUCTION

Exacerbation of atopic dermatitis can be associated with bacterial infection. The skin of patients is colonized with Staphylococcus aureus in 90% of cases. An attempt has been made to demonstrate that eradication significantly reduces the severity of the disease. Studies indicate the efficacy of topical antibiotics, topical corticosteroids and calcineurin inhibitors. Due to increasing resistance to drugs and the defective antimicrobial peptide profile, decolonization is virtually impossible.

AIM

To determine the prevalence of S. aureus colonization among patients with atopic dermatitis and to assess antimicrobial susceptibility of isolated strains to antibiotics, especially fusidic acid and mupirocin.

MATERIAL AND METHODS

One hundred patients with atopic dermatitis and 50 healthy subjects were microbiologically assessed for the carriage of S. aureus. Antimicrobial susceptibility tests were performed using the broth-microdilution method for antibiotics: ampicillin, ciprofloxacin, daptomycin, erythromycin, fusidic acid, linezolid, lincomycin, mupirocin, tetracycline and vancomycin.

RESULTS

Staphylococcus aureus strains were isolated from the majority of our patients, either from the skin (71%) or the anterior nares (67%). In the present study, 10% of isolations represented methicillin-resistant S. aureus (MRSA). Antibiotics exhibited diverse activities against clinical isolates of S. aureus. Among those tested, the highest rates of resistance were shown for ampicillin - 58.5%, lincomycin - 37.5% and erythromycin - 31.0%. Enhanced resistance levels were expressed to mupirocin (17.5%) and fusidic acid (15.5%).

CONCLUSIONS

According to the increasing rate of resistance and quick recolonization after discontinuation of the treatment, chronic use of topical antibiotics is not recommended and should be limited to exacerbation of atopic dermatitis with clinical signs of bacterial infection.

Risk of Skin and Soft Tissue Infections among Children Found to be Staphylococcus aureus MRSA USA300 Carriers

Introduction

The purpose of this study was to examine community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) carriage and infections and determine risk factors associated specifically with MRSA USA300.

Methods

We conducted a case control study in a pediatric emergency department. Nasal and axillary swabs were collected, and participants were interviewed for risk factors. The primary outcome was the proportion of S. aureus carriers among those presenting with and without a skin and soft tissue infection (SSTI). We further categorized S. aureus carriers into MRSA USA300 carriers or non-MRSA USA300 carriers.

Results

We found the MRSA USA300 carriage rate was higher in children less than two years of age, those with an SSTI, children with recent antibiotic use, and those with a family history of SSTI. MRSA USA300 carriers were also more likely to have lower income compared to non-MRSA USA300 carriers and no S. aureus carriers. Rates of Panton-Valentine leukocidin (PVL) genes were higher in MRSA carriage isolates with an SSTI, compared to MRSA carriage isolates of patients without an SSTI. There was an association between MRSA USA300 carriage and presence of PVL in those diagnosed with an abscess.

Conclusion

Children younger than two years were at highest risk for MRSA USA300 carriage. Lower income, recent antibiotic use, and previous or family history of SSTI were risk factors for MRSA USA300 carriage. There is a high association between MRSA USA300 nasal/axillary carriage and presence of PVL in those with abscesses.

Management of Infectious Aspects of Atopic Dermatitis in Primary Care: A Resident Survey

Atopic dermatitis (AD) is the most common skin disease encountered by pediatric primary care providers. To describe the knowledge, attitudes, and practices of primary care residents in the management of infectious aspects of pediatric AD, an anonymous web-based survey was offered to all residents in the pediatric and family medicine departments at 3 New York City hospitals. Eighty residents responded. Most (62%) reported seeing 5 to 14 patients with AD monthly. Twenty-seven percent reported obtaining cultures prior to prescribing oral antibiotics most of the time, while 8% reported doing so before giving topical antibiotics. Most respondents (60%) reported never/rarely recommending dilute bleach baths, and family medicine residents were significantly more likely to report never doing so (67% vs 16%, P < .001). Greater education on the use of cultures to guide treatment and potential benefits of dilute bleach baths is needed, especially given increasing antibiotic resistance.

Change in Antimicrobial Susceptibility of Skin-Colonizing Staphylococcus aureus in Korean Patients with Atopic Dermatitis during Ten-Year Period

BACKGROUND

A small subset of adolescents atopic dermatitis (AD) tends to persist. This also leads to get more antibiotics exposure with advancing years. Antibiotic resistance has been regarded as a serious problem during Staphylococcus aureus treatment, especially methicillin-resistant S. aureus (MRSA).

OBJECTIVE

It was investigated the S. aureus colonization frequency in the skin lesions and anterior nares of adolescent AD patients and evaluated the changes in S. aureus antimicrobial susceptibility for years.

METHODS

Patients who visited our clinic from September 2003 to August 2005 were classified into group A, and patients who visited from August 2010 to March 2012 were classified into group B. To investigate the differences with regard to patients' age and disease duration, the patients were subdivided into groups according to age. Lesional and nasal specimens were examined.

RESULTS

Among the 295 AD patients, the total S. aureus colonization rate in skin lesions was 66.9% (95/142) for group A and 78.4% (120/153) for group B. No significant changes in the systemic antimicrobial susceptibilities of S. aureus strains isolated from adolescent AD patients were observed during about 10-year period. The increased trend of MRSA isolation in recent adolescent AD outpatients suggest that the community including school could be the source of S. aureus antibiotic resistance and higher fusidic acid resistance rates provides evidence of imprudent topical use.

CONCLUSION

Relatively high MRSA isolation and fusidic acid resistance rates in recent AD patients suggest that the community harbors antibiotic-resistant S. aureus.

Genetic lineages and antimicrobial resistance genotypes in Staphylococcus aureus from children with atopic dermatitis: detection of clonal complexes CC1, CC97 and CC398

The objective was to analyse the genetic lineages of Staphylococcus aureus recovered from nasal and skin samples of atopic dermatitis (AD) paediatric patients, and to characterize the antimicrobial resistance phenotype-genotype and the immune-evasion-cluster (IEC) type of isolates. Forty S. aureus isolates from 35 patients (skin: 26; nasal samples: 14) were characterized. Isolates were submitted to spa-, agr- and multilocus sequence typing. All S. aureus strains analyzed were methicillin-susceptible (MSSA). High genetic diversity was detected among the 40 MSSA isolates (especially among skin isolates), with detection of 27 different spa-types, 20 sequence-types and 16 clonal complexes (CCs). Lineages CC30 and CC5 were predominant among nasal isolates (71% vs 23% skin). Thirteen different CCs were detected among skin isolates, with detection of clades CC1, CC9 and CC398. Antimicrobial resistance rates detected were higher in skin than in nasal isolates, especially for macrolides, aminoglycosides, lincosamides and mupirocin. MSSA strains were characterized into five IEC-types, being A, B and F the predominant ones. MSSA strains of lineages CC45 and CC5 were detected in almost all cases in AD patients with severe Scoring Atopic Dermatitis (SCORAD) and lineages CC8, and CC30 in those with mild or moderate one. As conclusion, high-clonal-diversity was detected among MSSA from AD patients, especially in skin-isolates. Colonization with S. aureus of some CCs seems more associated with AD severity than other lineages.

Serious Complications from Staphylococcal aureus in Atopic Dermatitis

Colonization with Staphylococcal aureus is markedly more frequent in individuals with atopic dermatitis (AD) than in unaffected individuals. Chronic scratching leads to worsening of an existing defect in the epidermal barrier, which can allow S. aureus invasion into the bloodstream and subsequent systemic infections. We report two unusual cases of systemic illness in individuals with AD. One developed infective endocarditis followed by a stroke and the other developed septic arthritis and osteomyelitis. We performed an extensive literature review of reported systemic complications caused by S. aureus in patients with AD. Although reports are rare, practitioners should be aware of these important, albeit unlikely, complications of staphylococcal superinfections in individuals with AD.

Correlation Between Serum 25-Hydroxyvitamin D and Virulence Genes of Staphylococcus aureus Isolates Colonizing Children with Atopic Dermatitis

The skin of children with atopic dermatitis (AD) is colonized with Staphylococcus aureus more frequently than that of their peers. We investigated the prevalence of skin and nares colonization by S. aureus in children with AD, the virulence genes of the isolates, and their association with allergy, AD severity, and serum vitamin D (25(OH)D). This was an observational, cross-sectional study in a sample of children diagnosed with AD in two settings in Spain. The samples were collected in 2012. Swabs from affected skin and nares were taken for microbiologic culture. The prevalence of S. aureus and presence of 17 staphylococcal virulence genes were studied using polymerase chain reaction. A total of 114 patients with a mean age of 5.7 ± 4.1 (range 3 mos to 14 yrs) were included in the study. Swabs were taken from the skin of 113 individuals with AD and from the nares of 85; 28.3% had S. aureus on the skin, which was significantly associated with positive allergen-specific immunoglobulin E antibodies and higher Scoring Atopic Dermatitis (SCORAD) scores in the multivariate analysis. The presence of virulence factors tsst-1, eta, cna, aur, and sec in cutaneous S. aureus isolates was associated with lower serum levels of 25(OH)D. S. aureus on nasal swabs correlated with its presence on the skin and was associated with lower 25(OH)D levels. In conclusion, S. aureus colonization is associated with allergy and severity in AD, whereas certain virulence genes are associated with lower serum 25(OH)D levels.

Diagnosis of Atopic Dermatitis: Mimics, Overlaps, and Complications

Atopic dermatitis (AD) is one of the most common skin diseases affecting infants and children. A smaller subset of adults has persistent or new-onset AD. AD is characterized by pruritus, erythema, induration, and scale, but these features are also typical of several other conditions that can mimic, coexist with, or complicate AD. These include inflammatory skin conditions, infections, infestations, malignancies, genetic disorders, immunodeficiency disorders, nutritional disorders, graft-versus-host disease, and drug eruptions. Familiarity of the spectrum of these diseases and their distinguishing features is critical for correct and timely diagnosis and optimal treatment.

High prevalence of mupirocin resistance in Staphylococcus aureus isolates from a pediatric population

Topical mupirocin is used widely to treat skin and soft tissue infections and to eradicate nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). Few studies to date have characterized the rates of S. aureus mupirocin resistance in pediatric populations. We retrospectively studied 358 unique S. aureus isolates obtained from 249 children seen in a predominantly outpatient setting by the Division of Pediatric Dermatology at a major academic center in New York City between 1 May 2012 and 17 September 2013. Mupirocin resistance rates and the associated risk factors were determined using a logistic regression analysis. In our patient population, 19.3% of patients had mupirocin-resistant S. aureus isolates at the time of their first culture, and 22.1% of patients with S. aureus infection had a mupirocin-resistant isolate at some time during the study period. Overall, 31.3% of all S. aureus isolates collected during the study period were resistant to mupirocin. Prior mupirocin use was strongly correlated (odds ratio [OR] = 26.5; P = <0.001) with mupirocin resistance. Additional risk factors for mupirocin resistance included methicillin resistance, atopic dermatitis (AD), epidermolysis bullosa (EB), immunosuppression, and residence in northern Manhattan and the Bronx. Resistance to mupirocin is widespread in children with dermatologic complaints in the New York City area, and given the strong association with mupirocin exposure, it is likely that mupirocin use contributes to the increased resistance. Routine mupirocin testing may be important for MRSA decolonization strategies or the treatment of minor skin infections in children.

Atopic dermatitis in children

A 7-year-old girl presented with atopic dermatitis (AD) that did not respond to standard therapy. She was avoiding dairy, egg, and wheat in her diet because of a history of skin flares. Her weight gain was poor, and laboratory test results showed low iron and zinc levels. Over the previous 6 months, she had been prescribed numerous courses of antibiotics, but, despite this, she continued to have secondary skin infections as well as deep circumscribed erosions on her shins. She was awake much of the night because of scratching and displayed repetitive and habitual behavior. She also had troublesome allergic rhinoconjunctivitis with positive allergy testing results to house dust mite. Methicillin-resistant Staphylococcus aureus was isolated from her skin, which was successfully treated with appropriate antibiotics and flares controlled with topical antiseptics and better personal and caregiver hygiene. Although milk, egg, and wheat specific IgE were raised, these foods were successfully reintroduced back into her diet with improvement of her nutritional status and no flare of her AD. In view of her habitual behavior and family history of obsessive compulsive disorder, she underwent cognitive behavioral therapy, and her general well-being, sleep, and ulcers over her shins improved. Despite high house dust mite-specific IgE, house dust mite sublingual immunotherapy led to no additional improvement in her AD although it did improve her rhinitis. Although there may be no "quick fixes" in patients with AD, the clinician should be aware of antimicrobial, allergen, and educational and/or behavioral interventions, which may greatly improve eczema severity and the patient's well-being.

Emergence of multiresistant methicillin-resistant Staphylococcus aureus in two patients with atopic dermatitis requiring linezolid treatment

We report two patients with atopic dermatitis who developed methicillin-resistant Staphylococcus aureus (MRSA) skin infections resistant to clindamycin and trimethoprim-sulfamethoxazole requiring repeated linezolid treatment. For one patient and family members who received an aggressive regimen of staphylococcal decolonization, including intranasal mupirocin, dilute bleach baths, and bleach cleansing of household items and surfaces, subsequent culture results demonstrated methicillin-susceptible S. aureus colonization and infection. These findings underscore the challenges presented by multiresistant MRSA infections in children with atopic dermatitis.

Prevalence of community-acquired methicillin-resistant Staphylococcus aureus and antibiotic resistance in patients with atopic dermatitis in Porto Alegre, Brazil

BACKGROUND

Atopic dermatitis (AD) is a skin manifestation of atopy caused by hyperreactivity to various antigens. Studies have shown that 60-100% of patients with this condition present with colonization by Staphylococcus aureus. Given increasing rates of antimicrobial resistance, the sensitivity to antimicrobials of S. aureus colonizing atopic patients has been investigated. Cross-sectional studies worldwide suggest that the prevalence of methicillin-resistant S. aureus infection (MRSA) in the AD population varies from 0% to 30.8%.

OBJECTIVES

The objectives of this study were to determinate the prevalence of S. aureus and MRSA in patients with AD in two dermatologic centers in Porto Alegre, Brazil.

METHODS

A total of 91 patients with AD attending two dermatologic centers in Porto Alegre were enrolled in this study from December 2009 to July 2011. Two skin swabs were taken from each patient, one from the nares and the other from a non-infected eczematous skin lesion. The swabs were sent to the laboratory, where standard procedures to isolate bacteria and identify S. aureus, antimicrobial resistance, and sensitivity patterns were carried out. The severity of AD was defined using the Eczema Area and Severity Index (EASI).

RESULTS

Of the 91 patients sampled, 67 (73.6%) patients were found to be positive for S. aureus colonization. Nasal swabs were positive in 55 (60.4%) patients, lesional swabs in 44 (48.4%) patients, and both lesional and nasal swabs were positive in 32 (35.2%) patients. Patients with positive swabs had a higher mean ± standard deviation EASI score [mean (9.1 ± 8.8)] compared with patients with negative swabs (3.9 ± 3.6) (P = 0.002). None of the 91 patients showed any evidence of MRSA infection. Overall, nearly 32% of the S. aureus isolated from nasal swabs and 36.40% of the S. aureus isolated from lesional swabs was resistant to erythromycin.

CONCLUSIONS

The results of this study confirm a high rate of S. aureus colonization in pediatric patients with AD and indicate a relevant association between colonization and high EASI score. No MRSA was found in cultures from this sample of patients in southern Brazil. Nearly one-third of isolates were identified as resistant to erythromycin, an antibiotic that is commonly used in pediatric patients.

Novel sodium hypochlorite cleanser shows clinical response and excellent acceptability in the treatment of atopic dermatitis

The intermittent use of dilute sodium hypochlorite "bleach baths" has shown efficacy as adjunctive therapy for atopic dermatitis (AD). This feasibility study evaluated the clinical response and patient acceptability of treatment with a cleansing body wash containing sodium hypochlorite in children with AD. This was a 12-week open-label feasibility study of 18 children with AD conducted in a pediatric dermatology outpatient clinic between May 2011 and July 2012. Children with moderate to severe AD, defined as an Investigator Global Assessment (IGA) score of at least 3 on a 5-point scale, who were age 6 months and older and had lesional cultures positive for Staphylococcus aureus at baseline were included. Patients were instructed to wash 3 days/week for 12 weeks with the sodium hypochlorite-containing cleansing body wash. During the study period, patient's individualized topical and systemic treatment regimens were continued. Clinical response to treatment was measured using an IGA score and the percentage of body surface area (BSA) affected. Parents were also administered a retrospective questionnaire evaluating acceptability of the product. There was a statistically significant reduction in IGA score at all time points, with an overall mean reduction from baseline to final measurement using the last observation carried forward in all patients of 1.0 (p = 0.001, n = 18). Similarly the mean reduction of BSA affected was 14.8% (p = 0.005, n = 18). Parents reported that the body wash was significantly easier to use than traditional bleach baths (p < 0.001). The significant reductions in clinical disease severity scores with use of this formulation are encouraging.

Empiric antibiotics and outcomes of children hospitalized with eczema herpeticum

Although patients with eczema herpeticum often receive antibiotics for presumed bacterial coinfection, the effect of empiric antibiotic therapy is unknown. Our objective therefore was to determine the association between empiric antibiotics and outcomes in children hospitalized with eczema herpeticum. We conducted a multicenter retrospective cohort study of 1,150 children ages 2 months to 17 years admitted with eczema herpeticum between January 1, 2001, and March 31, 2010, to 42 tertiary care children's hospitals in the Pediatric Health Information System. All patients received antibiotics during the hospitalization. Multivariable linear regression models determined the association between empiric antibiotic therapy and the main outcome measure: hospital length of stay (LOS). There were no deaths during the study period. Receipt of empiric antibiotics was not associated with a change in the LOS on unadjusted or multivariable analysis. The class of empiric antibiotic was not associated with the LOS except for receipt of vancomycin, which was associated with a longer LOS (21% adjusted longer LOS, 95% confidence interval (CI) = 8-35%; p = 0.001). When restricted to patients with a bloodstream infection, receipt of empiric antibiotics was associated with a 51% adjusted shorter LOS (95% CI = -24 to -68%; p = 0.002). In children hospitalized with eczema herpeticum, empiric antibiotic therapy was not associated with a shorter LOS overall, but was associated with a shorter LOS in patients with a bloodstream infection. These findings highlight the importance of early recognition of systemic bacterial illness in children with eczema herpeticum. Empiric antibiotics did not affect mortality, which is low.

Addressing antimicrobial resistance to treat children with atopic dermatitis in a tertiary pediatric allergy clinic

BACKGROUND

Secondary skin infection with Staphylococcus aureus is a significant problem in atopic dermatitis (AD) patients.

OBJECTIVE

This study evaluated antimicrobial resistance patterns of S aureus isolates from skin lesions in AD patients and empiric antimicrobial prescribing patterns.

METHODS

Resistance patterns from positive skin cultures obtained from AD patients in the Allergy/Immunology clinic from May 1, 2006, to December 31, 2008, were compared with all outpatient wound cultures over the same period.

RESULTS

Fifty-nine cultures were obtained from 38 AD patients. S aureus was the most common pathogen cultured from AD patients (53/59 cultures). S aureus resistance to clindamycin and methicillin differed significantly between the study group and the outpatient reference population (37.7% vs 9.4% and 45.3% vs 76.4%). Clindamycin was the most commonly prescribed antimicrobial (59%). Overall, 31.4% of organisms showed resistance to the antimicrobial prescribed.

CONCLUSIONS

Susceptibility profiles of S aureus isolates from AD patients vary significantly from that of the general population.

Bacterial skin colonization and infections in patients with atopic dermatitis

Atopic Dermatitis is a chronic inflammatory skin disease that affects a large number of children and adults. The disease results from an interaction between genetic predisposition, host environment, skin barrier defects, and immunological factors. A major aggravating factor associated with Atopic Dermatitis is the presence of microorganisms on the patient's skin surface. Staphylococcus aureus and Streptococcus pyogenes, for instance, can exacerbate chronic skin inflammation. As a result, antimicrobials have often been prescribed to control the acute phase of the disease. However, increased bacterial resistance to antimicrobial agents has made it difficult for dermatologists to prescribe appropriate medication. In the presence of disseminated dermatitis with secondary infection, systemic antibiotics need to be prescribed; however, treatment should be individualized, in an attempt to find the most effective antibiotic with fewer side effects. Also, the medication should be used for as short as possible in order to minimize bacterial resistance.

Treatment outcomes of secondarily impetiginized pediatric atopic dermatitis lesions and the role of oral antibiotics

Patients with atopic dermatitis (AD) are predisposed to infection with Staphylococcus aureus, which worsens their skin disease; it has been postulated that the lack of antimicrobial peptides due to aberrant allergic inflammation in skin with AD could mediate this enhanced bacterial susceptibility. We sought to characterize the amounts of S. aureus and biological products found in infected AD lesions and whether treatment with topical corticosteroids and oral cephalexin as the only antimicrobial improved outcomes. Fifty-nine children with clinically and S. aureus-positive impetiginized lesions of AD were enrolled in this study. A lesion was graded clinically using the Eczema Area and Severity Index, and wash fluid was obtained from the lesion for quantitative bacterial culture and antibiotic sensitivities and measurement of bacterial products and cytokines. Subjects were re-evaluated 2 weeks after treatment. Improvement in the clinical and inflammatory characteristics of impetiginized lesions were noted, even in the 15% of lesions infected with Methicillin-resistant S. aureus (MRSA). In a subgroup of subjects whose lesions did not contain S. aureus 2 weeks after initiating treatment, beta-defensin levels were higher at both visits than in normal skin. Treatment of uncomplicated impetiginized pediatric AD with topical corticosteroids and cephalexin results in significant clinical improvement, even in subjects infected with MRSA. We propose that the inhibition of abnormal inflammation by the treatment regimen, resulting in the high levels of defensins, is involved in the improvement of AD and that systemic antibiotics do not appear to be necessary in secondary impetiginized AD.

Comorbidity in Atopic Dermatitis

The negative impact of atopic dermatitis (AD) often extends beyond the skin. Children with AD experience increased rates of infectious, mental health, and allergic diseases compared to their non-atopic peers. The mechanisms underlying these associations remain elusive. New insights from genetic and epidermal research pinpoint the skin barrier as a primary initiator of AD. Epicutaneous sensitization represents an intriguing new model which links a disrupted skin barrier to the later development of IgE-mediated diseases in patients with AD. Recent epidemiological studies have identified new comorbidities linked to AD as well, including several mental health disorders and obesity. This manuscript reviews the recent literature regarding both classic and newly described AD comorbidities.

Delayed acyclovir and outcomes of children hospitalized with eczema herpeticum

OBJECTIVE

To describe the epidemiology and outcomes of children hospitalized with eczema herpeticum and to determine the association with delayed acyclovir on outcomes.

PATIENTS AND METHODS

This was a multicenter retrospective cohort study conducted between January 1, 2001, and March 31, 2010, of 1331 children aged 2 months to 17 years with eczema herpeticum from 42 tertiary care children's hospitals in the Pediatric Health Information System database. Multivariable linear regression models determined the association between delayed acyclovir therapy and the main outcome measure: hospital length of stay (LOS).

RESULTS

There were no deaths during the study period. Staphylococcus aureus infection was diagnosed in 30.3% of the patients; 3.9% of the patients had a bloodstream infection. Fifty-one patients (3.8%) required ICU admission. There were 893 patients (67.1%) who received acyclovir on the first day of admission. The median LOS increased with each day delay in acyclovir initiation. In multivariable analysis, delay of acyclovir initiation by 1 day was associated with an 11% increased LOS (95% confidence interval [CI]: 3%-20%; P = .008), and LOS increased by 41% when acyclovir was started on day 3 (95% CI: 19%-67%; P < .001) and by 98% when started on day 4 to 7 (95% CI: 60%-145%; P < .001). Use of topical corticosteroids on day 1 of hospitalization was not associated with LOS.

CONCLUSIONS

Delay of acyclovir initiation is associated with increased LOS in hospitalized children with eczema herpeticum. Use of topical corticosteroids on admission is not associated with increased LOS. The mortality rate of hospitalized children with eczema herpeticum is low.