Christine T. Lauren

High Prevalence of Mupirocin Resistance in Staphylococcus aureus Isolates from a Pediatric Population

ABSTRACT 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.

Methicillin-Resistant Staphylococcus aureus Adaptation to Human Keratinocytes

ABSTRACT Skin is the most common site of Staphylococcus aureus infection. While most of these infections are self-limited, recurrent infections are common. Keratinocytes and recruited immune cells participate in skin defense against infection. We postulated that S. aureus is able to adapt to the milieu within human keratinocytes to avoid keratinocyte-mediated clearance. From a collection of S. aureus isolated from chronically infected patients with atopic dermatitis, we noted 22% had an agr mutant-like phenotype. Using several models of human skin infection, we demonstrate that toxin-deficient, agr mutants of methicillin-resistant S. aureus (MRSA) USA300 are able to persist within keratinocytes by stimulating autophagy and evading caspase-1 and inflammasome activation. MRSA infection induced keratinocyte autophagy, as evidenced by galectin-8 and LC3 accumulation. Autophagy promoted the degradation of inflammasome components and facilitated staphylococcal survival. The recovery of more than 58% agr or RNAIII mutants (P < 0.0001) of an inoculum of wild-type (WT) MRSA from within wortmannin-treated keratinocytes compared to control keratinocytes reflected the survival advantage for mutants no longer expressing agr-dependent toxins. Our results illustrate the dynamic interplay between S. aureus and keratinocytes that can result in the selection of mutants that have adapted specifically to evade keratinocyte-mediated clearance mechanisms. IMPORTANCE Human skin is a major site of staphylococcal infection, and keratinocytes actively participate in eradication of these pathogens. We demonstrate that methicillin-resistant Staphylococcus aureus (MRSA) is ingested by keratinocytes and activates caspase-1-mediated clearance through pyroptosis. Toxin-deficient MRSA mutants are selected within keratinocytes that fail to induce caspase-1 activity and keratinocyte-mediated clearance. These intracellular staphylococci induce autophagy that enhances their intracellular survival by diminishing inflammasome components. These findings suggest that S. aureus mutants, by exploiting autophagy, can persist within human keratinocytes. Human skin is a major site of staphylococcal infection, and keratinocytes actively participate in eradication of these pathogens. We demonstrate that methicillin-resistant Staphylococcus aureus (MRSA) is ingested by keratinocytes and activates caspase-1-mediated clearance through pyroptosis. Toxin-deficient MRSA mutants are selected within keratinocytes that fail to induce caspase-1 activity and keratinocyte-mediated clearance. These intracellular staphylococci induce autophagy that enhances their intracellular survival by diminishing inflammasome components. These findings suggest that S. aureus mutants, by exploiting autophagy, can persist within human keratinocytes.

Topical Timolol Maleate Treatment of Infantile Hemangiomas

BACKGROUND: There has been a dramatic increase in the off-label use of ophthalmic timolol maleate, a β-blocker used for infantile hemangioma (IH) treatment as a topical counterpart to oral propranolol. Its safety and efficacy in a pediatric population with IH have not been evaluated in a large cohort. Our goal was to retrospectively assess timolol’s effectiveness, discern characteristics associated with response, and document reported adverse events. METHODS: A multicenter retrospective cohort study of 731 patients treated with topical timolol was completed at 9 centers. Inclusion required an IH suitable for timolol in the treating physician’s judgment and access to clinical details including photographs. Logistic regression analysis and descriptive statistics were performed. Primary outcome measures were efficacy assessed by using visual analog scales for color and for size, extent, and volume from review of digital photographs taken as standard of care. RESULTS: Most IHs were localized (80.1%) and superficial (55.3%). Risk of disfigurement was the most common indication for therapy (74.3%). Duration of therapy (P < .0001), initial thinness (P = .008), and subtype (P = .031) were significant predictors of response. Best response occurred in superficial IHs <1 mm thick. Fifty-three (7.3%) required subsequent therapy with systemic β-blocker. Adverse events were mild, occurring in 25 (3.4%) patients. No cardiovascular side effects were documented. CONCLUSIONS: Timolol seems to be a well-tolerated, safe treatment option with moderate to good effectiveness, demonstrating best response in thin, superficial IHs regardless of pretreatment size. Timolol can be recommended as an alternative to systemic β-blockers and watchful waiting for many patients.

Dominant de novo mutations in GJA1 cause erythrokeratodermia variabilis et progressiva, without features of oculodentodigital dysplasia

Genetic investigation of inherited skin disorders has informed understanding of skin self-renewal, differentiation, and barrier function. Erythrokeratodermia variabilis et progressiva (EKVP) is a rare, inherited skin disease characterized by transient figurate patches of erythema, localized or generalized scaling, and frequent palmoplantar keratoderma. By employing exome sequencing, we show that de novo missense mutations in GJA1 (gap junction protein alpha 1) cause EKVP. The severe, progressive skin disease in EKVP subjects with GJA1 mutations is distinct from limited cutaneous findings rarely found in the systemic disorder oculodentodigital dysplasia, also caused by dominant GJA1 mutations. GJA1 encodes connexin 43 (Cx43), the most widely expressed gap junction protein. We show that the GJA1 mutations in EKVP subjects lead to disruption of Cx43 membrane localization, and aggregation within the Golgi. These findings reveal a critical role for Cx43 in epidermal homeostasis, and provide evidence of organ-specific pathobiology resulting from different mutations within GJA1.

Case Report of Subcutaneous Nodules and Sterile Abscesses Due to Delayed Type Hypersensitivity to Aluminum-Containing Vaccines

Routine childhood immunizations have resulted in great reductions in vaccine-preventable infectious diseases. Vaccine-related adverse events, albeit rare, can be of significant consequence. Although anaphylaxis, or type I hypersensitivity, is recognized as a potential reaction after vaccination, delayed type hypersensitivity or type IV reactions are less so. We present a case of persistent subcutaneous nodules and sterile abscesses in the setting of delayed type hypersensitivity to aluminum, confirmed by patch testing and recurrence on re-exposure. We review sources of aluminum in common immunizations, principles for treatment, and strategies for management of future vaccinations for this patient.

CM-AVM syndrome in a neonate: case report and treatment with a novel flow reduction strategy

Mutations in the RASA-1 gene underlie several related disorders of vasculogenesis. Capillary malformation-arteriovenous malformation (CM-AVM) is one such entity and was recently encountered in a neonate who demonstrated its clinical and radiologic features. A single mutation in the RASA-1 gene was detected.A novel flow reduction strategy was employed to a large AVM affecting the patient’s upper limb. The imaging findings, surgical procedure and patient’s improved post-operative state are described.

Feed and Wrap MRI Technique in Infants

The feed and wrap technique refers to the use of feeding and swaddling to induce natural sleep in infants. It can be used prior to an magnetic resonance imaging (MRI) scan, avoiding sedation or anesthesia. We performed a retrospective review of feed and wrap MRI scans in infants 3 months or younger over a 2-year period at our center (279 scans) to evaluate the efficacy of this technique. Of scan results reviewed, 79% addressed the clinical question, 20% partially addressed the clinical question, and 1% were technically inadequate. History of preterm birth (odds ratio [OR] = 2.368; P = .032) and spine MRI (OR = 2.821; P = .001) were associated with a less-successful scan outcome. The feed and wrap technique can be used successfully in infants undergoing MRI; however, it may be less successful in preterm infants and those requiring spinal MRI. A standardized technique performed by experienced personnel may avoid anesthesia and sedation in infants who require MRI.

Management of afebrile neonates with pustules and vesicles in a pediatric emergency department

To assess the management and outcomes of vesicles and pustules in afebrile neonates presenting to the pediatric emergency department.

Texting atopic dermatitis patients to optimize learning and eczema area and severity index scores: A pilot randomized control trial

Atopic dermatitis is a common, chronic, debilitating disease. Poor adherence to treatment is the most important preventable contributor to adverse outcomes. Thus, improving adherence can improve patient outcomes. Text message reminders with embedded condition‐specific information have been shown to improve pediatric immunization adherence but have not been assessed in atopic dermatitis. The objective was to assess the effect of daily text messages on Eczema Area Severity Index scores and caregiver knowledge of atopic dermatitis.

Carcinoma en cuirasse caused by pleomorphic lobular carcinoma of the breast in a man

Breast carcinoma, the most common malignancy in women, is rarely diagnosed in men. Approximately 1,910 new cases of breast carcinoma in men are reported annually1 compared with more than 230,000 new cases in women.2 Most male cases (90%) are of the invasive ductal subtype.3 The lifetime risk of breast cancer for men in the general population is 0.1%.1 Genetic predisposition significantly heightens this risk, with mutations in BRCA2 increasing the lifetime risk to an estimated 5% to 10%.1 Inactivation of other tumor suppressors, including BRCA1, PTEN, p53, and CHEK2, is also found to confer an increased risk in men.1, 3 Congenital disorders such as Klinefelters syndrome contribute to at least 3% of the incidence of all male breast cancer.1 We report a 77-year-old man presenting with a painful right axillary mass diagnosed as metastatic carcinoma of unknown primary. Despite multiple treatment modalities, his disease progressed to the brain, lungs, and skin as carcinoma en cuirasse. Histopathologic diagnosis at autopsy was pleomorphic lobular carcinoma (PLC), an uncommon subtype of breast cancer that is reported rarely in men.