Superantigen Encoding Genes in Staphylococcus aureus Isolated from Lesional Skin, Non-Lesional Skin, and Nares of Patients with Atopic Dermatitis.

Patients with atopic dermatitis (AD) are more likely than healthy individuals to harbour Staphylococcus aureus on their skin. Superantigens (SAgs) produced by specific S. aureus strains may contribute to AD-associated skin inflammation. The present study compared the prevalence and types of SAg-encoding genes between S. aureus isolated from patients with AD and from  controls, and within the AD group between isolates from different sampling sites (lesional skin, non-lesional skin, and nares). This retrospective case-control study extracted data from 2 previous studies that examined S. aureus using whole-genome sequencing. The 138 S. aureus isolates obtained from 71 AD patients contained 349 SAg-encoding genes; 22 (6.3%) were found in isolates from nares (0.4 ± 0.6 genes per isolate), 99 (28.4%) in isolates from non-lesional skin (3.7 ± 3.9), and 228 (65.3%) in isolates from lesional skin (4.2 ± 4.5). S. aureus (n = 101) from the control group contained 594 SAg-encoding genes (5.9 ± 4.2). Of the S. aureus isolated from lesional AD skin, 69% carried at least 1 gene encoding SAg compared with 33% of AD nasal isolates. SAg could be a factor in the pathogenesis of a subset of AD patients.

IgG and IgM responses to the Plasmodium falciparum asexual stage antigens reflect respectively protection against malaria during pregnancy and infanthood.

BACKGROUND: Plasmodium falciparum malaria is a public health issue mostly seen in tropical countries. Until now, there is no effective malaria vaccine against antigens specific to the blood-stage of P. falciparum infection. Because the pathogenesis of malarial disease results from blood-stage infection, it is essential to identify the most promising blood-stage vaccine candidate antigens under natural exposure to malaria infection. METHODS: A cohort of 400 pregnant women and their infants was implemented in South Benin. An active and passive protocol of malaria surveillance was established during pregnancy and infancy to precisely ascertain malaria infections during the follow-up. Twenty-eight antibody (Ab) responses specific to seven malaria candidate vaccine antigens were repeatedly quantified during pregnancy (3 time points) and infancy (6 time points) in order to study the Ab kinetics and their protective role. Abs were quantified by ELISA and logistic, linear and cox-proportional hazard model were performed to analyse the associations between Ab responses and protection against malaria in mothers and infants, taking into account socio-economic factors and for infants an environmental risk of exposure. RESULTS: The levels of IgM against MSP1, MSP2 and MSP3 showed an early protective response against the onset of symptomatic malaria infections starting from the 18th month of life, whereas no association was found for IgG responses during infancy. In women, some IgG responses tend to be associated with a protection against malaria risk along pregnancy and at delivery, among them IgG3 against GLURP-R0 and IgG2 against MSP1. CONCLUSION: The main finding suggests that IgM should be considered in vaccine designs during infanthood. Investigation of the functional role played by IgM in malaria protection needs further attention.

In the eye of the ophthalmologist: the corneal microbiome in microbial keratitis.

PURPOSE: To describe the bacterial findings by a targeted sequencing approach from corneal samples of patients with microbial keratitis and factors influencing culture outcome of indirectly inoculated corneal specimen. METHODS: Prospective inclusion of patients fulfilling predefined criteria of microbial keratitis. Samples from the corneal lesion were collected and dispensed in liquid transport medium, from which both culture and targeted amplification and sequencing of the V3-V4 region of the 16S rRNA gene were carried out. Additional standard corneal culture from the corneal lesions was also performed. Factors influencing culture outcome of indirectly inoculated corneal samples were identified by a multivariate regression model incorporating quantitative data from sequencing. RESULTS: Among the 94 included patients with microbial keratitis, contact lens wear (n = 69; 73%) was the most common risk factor. Contact lens wearers displayed significant differences in the bacterial community composition of the corneal lesion compared to no lens wearers, with higher abundance of Staphylococcus spp., Corynebacterium spp., and Stenotrophomonas maltophilia. Targeted sequencing detected a potential corneal pathogen in the highest proportional abundance among 9 of the 24 (38%) culture-negative patients with microbial keratitis. Age, bacterial density in the sample, and prior antibiotic treatment significantly influenced culture outcome of indirectly inoculated corneal samples. CONCLUSION: Targeted sequencing may provide insights on pathogens in both culture negative episodes of microbial keratitis and among subgroups of patients with microbial keratitis as well as factors influencing culture outcome of indirectly inoculated corneal samples.

Increase in invasive group A streptococcal infections and emergence of novel, rapidly expanding sub-lineage of the virulent Streptococcus pyogenes M1 clone, Denmark, 2023.

A highly virulent sub-lineage of the Streptococcus pyogenes M1 clone has been rapidly expanding throughout Denmark since late 2022 and now accounts for 30% of the new invasive group A streptococcal infections. We aimed to investigate whether a shift in variant composition can account for the high incidence rates observed over winter 2022/23, or if these are better explained by the impact of COVID-19-related restrictions on population immunity and carriage of group A Streptococcus.

Comparative subgenomic mRNA profiles of SARS-CoV-2 Alpha, Delta and Omicron BA.1, BA.2 and BA.5 sub-lineages using Danish COVID-19 genomic surveillance data.

BACKGROUND: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has rapidly spread worldwide in the population since it was first detected in late 2019. The transcription and replication of coronaviruses, although not fully understood, is characterised by the production of genomic length RNA and shorter subgenomic RNAs to make viral proteins and ultimately progeny virions. Observed levels of subgenomic RNAs differ between sub-lineages and open reading frames but their biological significance is presently unclear. METHODS: Using a large and diverse panel of virus sequencing data produced as part of the Danish COVID-19 routine surveillance together with information in electronic health registries, we assessed the association of subgenomic RNA levels with demographic and clinical variables of the infected individuals. FINDINGS: Our findings suggest no significant statistical relationship between levels of subgenomic RNAs and host-related factors. INTERPRETATION: Differences between lineages and subgenomic ORFs may be related to differences in target cell tropism, early virus replication/transcription kinetics or sequence features. FUNDING: The author(s) received no specific funding for this work.

Dramatic increase in slaughter condemnations due to Escherichia coli ST23 and ST101 within the Danish broiler production.

Escherichia coli constitutes a major challenge to poultry even when the prevalence of colibacillosis is low. Additionally, specific E. coli strains can severely enhance the detrimental effects on productivity, animal welfare and antimicrobial use. In 2019-2020, a dramatic increase in colibacillosis occurred among Danish broilers causing late-onset mortality and high slaughter condemnations. In the present study, the pathology and causative E. coli-types were characterised. Furthermore, the outbreak-related strains were compared to isolates from concurrent "background" colibacillosis. During the study, 1039 birds were subjected to a comprehensive post-mortem examination, and a total of 349 E. coli isolates were sequenced and characterised by multi-locus sequence typing, virulence and resistance gene presence, plasmid replicon content and phylogenetic analysis. Productivity data from outbreak flocks revealed a mortality of 6.34% ± 3.74 and a condemnation of 5.04% ± 3.67. Contrary, the numbers were 3.18% ± 1.57% and 1.02% ± 0.4 among non-outbreak flocks, respectively. Major lesions were cellulitis (46.82%), airsacculitis (67.63%), pericarditis (55.49%), perihepatitis (41.04%) and femoral head necrosis with physeal/metaphyseal involvement (44.51%). Among non-outbreak broilers, the prevalence was 4.46%, 7.64%, 7.01%, 3.82% and 8.28%, respectively. ST23 and ST101 dominated heavily in outbreak flocks, whereas non-outbreak related isolates consisted of various other STs. A low level of resistance markers was evident, except in few multidrug-resistant isolates. Within ST23 and ST101, 13 and 12 virulence genes were significantly over-represented compared to non-outbreak isolates. In conclusion, clonal lineages were documented as the cause of a devastating outbreak of colibacillosis with great prospects for future interventions.

Experience with sotrovimab treatment of SARS-CoV-2-infected patients in Denmark.

AIMS: To evaluate the experience with use of sotrovimab following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in high-risk groups. METHODS: In a nationwide, population-based cohort study, we identified all individuals treated with sotrovimab (N = 2933) and stratified them by 4 high-risk groups: (A) malignant haematological disease, (B) solid organ transplantation, (C) anti-CD20 therapy ≤1 year and (D) other risks. Cox regression analysis was used to calculate hazard ratios for hospitalization, death and associated prognostic factors. RESULTS: Of 2933 sotrovimab-treated individuals, 83% belonged to high-risk groups (37.6% haematological malignancy, 27.4% solid organ transplantation and 17.5% treatment with anti-CD20 ≤1 year). Only 17.8% had other risks (11.8% were pregnant, 10.7% primary immunodeficiency, 21.2% other malignancy, 4.3% received anti-CD20 >1 year and 52.0% other/unknown causes). Within 90 days of infusion, 30.2% were hospitalized and 5.3% died. The main prognostic factors were the predefined high-risk groups, mainly malignant haematological disease and age ≥65 years. Number of COVID-19 vaccines (≥3) was associated with a decreased risk of hospitalization. The Delta but not the Omicron BA.2 variant was associated with a higher risk of death compared to the BA.1 variant. CONCLUSION: More than 90% of the patients treated with sotrovimab belonged to the very high-risk groups as described in the Danish guidelines. Sotrovimab-treated individuals remained at a high risk of hospitalization and death which was strongly associated with the underlying immunocompromised state and age. Having received >3 COVID-19 vaccines was association with decreased risk of death and hospitalization.

Fc Gamma Receptor IIIB NA1/NA2/SH Polymorphisms Are Associated with Malaria Susceptibility and Antibody Levels to P. falciparum Merozoite Antigens in Beninese Children.

This paper aimed to investigate the influence of polymorphisms in the FCGR2A gene encoding R131H FcgRIIA variants and in the FCGR3B gene (108G > C, 114C > T, 194 A > G, 233C > A, 244 G > A and 316G > A) encoding FcgRIIIB-NA1, -NA2 and -SH variants on malaria susceptibility and antibody responses against P. falciparum merozoite antigens in Beninese children. An active malaria follow-up was conducted in infants from birth to 24 months of age in Allada, Benin. FCGR3B exon 3 was sequenced and FCGR2A exon 4 was genotyped. Antibodies directed to GLURP and MSP3 were quantified by ELISA. Association studies were performed using mixed-effect models. Individual carriage of FCGR3B 194 AA genotype was associated with a high number of malaria infections and a low level of IgG1 against MSP3 and GLURP-R0. High parasitemia and increased malaria infections were observed in infants carrying the FCGR3B*05 108C-114T-194A-233C-244A-316A haplotype. A reduced risk of malaria infections and low parasitemia were related to the carriages of the FCGR3B 108C-114T-194G-233C-244G-316A (FCGR3B*06), FCGR3B 108C−114T−194G−233A−244A−316A (FCGR3B*03 encoding for FcgRIIIB-SH) haplotypes and FCGR3B 297 TT genotype. Our results highlight the impact of FCGR3B polymorphisms on the individual susceptibility to malaria and antibody responses against MSP3 and GLURP in Beninese children.

Placental Malaria is Associated with Higher LILRB2 Expression in Monocyte Subsets and Lower Anti-Malarial IgG Antibodies During Infancy.

Background: Placental malaria (PM) is associated with a higher susceptibility of infants to Plasmodium falciparum (Pf) malaria. A hypothesis of immune tolerance has been suggested but no clear explanation has been provided so far. Our goal was to investigate the involvement of inhibitory receptors LILRB1 and LILRB2, known to drive immune evasion upon ligation with pathogen and/or host ligands, in PM-induced immune tolerance. Method: Infants of women with or without PM were enrolled in Allada, southern Benin, and followed-up for 24 months. Antibodies with specificity for five blood stage parasite antigens were quantified by ELISA, and the frequency of immune cell subsets was quantified by flow cytometry. LILRB1 or LILRB2 expression was assessed on cells collected at 18 and 24 months of age. Findings: Infants born to women with PM had a higher risk of developing symptomatic malaria than those born to women without PM (IRR=1.53, p=0.040), and such infants displayed a lower frequency of non-classical monocytes (OR=0.74, p=0.01) that overexpressed LILRB2 (OR=1.36, p=0.002). Moreover, infants born to women with PM had lower levels of cytophilic IgG and higher levels of IL-10 during active infection. Interpretation: Modulation of IgG and IL-10 levels could impair monocyte functions (opsonisation/phagocytosis) in infants born to women with PM, possibly contributing to their higher susceptibility to malaria. The long-lasting effect of PM on infants' monocytes was notable, raising questions about the capacity of ligands such as Rifins or HLA-I molecules to bind to LILRB1 and LILRB2 and to modulate immune responses, and about the reprogramming of neonatal monocytes/macrophages.

Molecular epidemiology of the SARS-CoV-2 variant Omicron BA.2 sub-lineage in Denmark, 29 November 2021 to 2 January 2022.

Following emergence of the SARS-CoV-2 variant Omicron in November 2021, the dominant BA.1 sub-lineage was replaced by the BA.2 sub-lineage in Denmark. We analysed the first 2,623 BA.2 cases from 29 November 2021 to 2 January 2022. No epidemiological or clinical differences were found between individuals infected with BA.1 versus BA.2. Phylogenetic analyses showed a geographic east-to-west transmission of BA.2 from the Capital Region with clusters expanding after the Christmas holidays. Mutational analysis shows distinct differences between BA.1 and BA.2.

Hand eczema and temporal variation of Staphylococcus aureus clonal complexes: A prospective observational study.

BACKGROUND: Hand eczema (HE) is frequently associated with Staphylococcus aureus; however, its role in the pathogenesis of HE is poorly understood. OBJECTIVE: To investigate the temporal variation in S aureus subtypes, ie, clonal complex (CC) types, on the hands and relate it to S aureus colonization in the nose and severity in a cohort of HE patients. METHODS: S aureus from the hands and nose of 50 adult HE patients and 50 controls was prospectively identified at 5 visits over 3 weeks. RESULTS: S aureus was identified on the hands of 23 (46%) patients at 2 or more visits and on the hands of 1 control once. Of the HE patients with S aureus colonization, 78% had the same S aureus CC type over time. Twenty-one patients had the same S aureus CC type on the hands and in the nose. Persistent colonization was strongly related to an increased disease severity. LIMITATIONS: A relatively small S aureus culture-positive population. CONCLUSION: The temporal stability of S aureus CC type and high occurrence of the identical subtypes on the hands and in the nose imply that S aureus colonization in patients with HE is of a more permanent nature. Taken together with the finding that persistent colonization and HE severity are clearly related, our results indicate that S aureus may contribute to the perpetuating course of HE.

Shifts in the Skin Microbiota after UVB Treatment in Adult Atopic Dermatitis.

BACKGROUND: The pathophysiology in atopic dermatitis (AD) is not fully understood, but immune dysfunction, skin barrier defects, and alterations of the skin microbiota are thought to play important roles. AD skin is frequently colonized with Staphylococcus aureus (S. aureus) and microbial diversity on lesional skin (LS) is reduced compared to on healthy skin. Treatment with narrow-band ultraviolet B (nb-UVB) leads to clinical improvement of the eczema and reduced abundance of S. aureus. However, in-depth knowledge of the temporal dynamics of the skin microbiota in AD in response to nb-UVB treatment is lacking and could provide important clues to decipher whether the microbial changes are primary drivers of the disease, or secondary to the inflammatory process. OBJECTIVES: To map the temporal shifts in the microbiota of the skin, nose, and throat in adult AD patients after nb-UVB treatment. METHODS: Skin swabs were taken from lesional AD skin (n = 16) before and after 3 treatments of nb-UVB, and after 6-8 weeks of full-body treatment. We also obtained samples from non-lesional skin (NLS) and from the nose and throat. All samples were characterized by 16S rRNA gene sequencing. RESULTS: We observed shifts towards higher diversity in the microbiota of lesional AD skin after 6-8 weeks of treatment, while the microbiota of NLS and of the nose/throat remained unchanged. After only 3 treatments with nb-UVB, there were no significant changes in the microbiota. CONCLUSION: Nb-UVB induces changes in the skin microbiota towards higher diversity, but the microbiota of the nose and throat are not altered.

Skin Microbiome in Patients with Hand Eczema and Healthy Controls: A Three-week Prospective Study.

The pathogenesis of chronic hand eczema remains unclear. Insights into the skin microbiome in hand eczema and its potential relevance to disease severity may help to elucidate the underlying mechanisms of hand eczema. The aim of this study was to characterize the microbiome in patients with hand eczema and healthy controls. A 5-visit prospective study was conducted over a period of 3 weeks. At each visit, bacterial swabs were taken from the hands of patients with hand eczema and controls. The microbiome was examined using DNA extraction and 16S rRNA amplicon sequencing (V3-V4 regions). Fifty patients with hand eczema and 50 controls were included (follow-up rate=100%). The baseline bacterial α-diversity was reduced on the hands of patients with hand eczema compared with controls (effect size=-0.31; 95% confidence interval (95% CI) -0.50; -0.11; p = 0.003). The dysbiosis on the patients' hands was stable over the study period, was associated with disease severity, and was characterized by reduced bacterial diversity and different bacterial community compositions.

Epidemiological characterisation of the first 785 SARS-CoV-2 Omicron variant cases in Denmark, December 2021.

By 9 December 2021, 785 SARS-CoV-2 Omicron variant cases have been identified in Denmark. Most cases were fully (76%) or booster-vaccinated (7.1%); 34 (4.3%) had a previous SARS-CoV-2 infection. The majority of cases with available information reported symptoms (509/666; 76%) and most were infected in Denmark (588/644; 91%). One in five cases cannot be linked to previous cases, indicating widespread community transmission. Nine cases have been hospitalised, one required intensive care and no deaths have been registered.

Changes in Skin and Nasal Microbiome and Staphylococcal Species Following Treatment of Atopic Dermatitis with Dupilumab.

Investigation of changes in the skin microbiome following treatment of atopic dermatitis (AD) with dupilumab may provide valuable insights into the skin microbiome as a therapeutic target. The aim of this study is to assess changes in the AD skin microbiome following treatment of AD with dupilumab (n = 27). E-swabs were collected from nose, lesional, and nonlesional skin before and after 16 weeks of dupilumab therapy, and the microbiome was analyzed by 16S rRNA and tuf gene sequencing. Data for 17 patients with milder disease receiving treatment with non-targeted therapies are also presented. The results show that both groups experienced clinical improvement (p < 0.001) following dupilumab therapy and that Shannon diversity increased and bacterial community structure changed. The relative abundance of the genus Staphylococcus (S.) and S. aureus decreased, while that of S. epidermidis and S. hominis increased. No significant changes were observed for patients receiving non-targeted treatments. The increases in S. epidermidis and S. hominis and the decrease in S. aureus correlated with clinical improvement. Furthermore, changes in S. hominis and S. epidermidis correlated inversely with S. aureus. In conclusion, treatment with dupilumab significantly changed the skin microbiome and decreased S. aureus. Our results suggest a favorable role of commensal staphylococci in AD.

Wearing Occlusive Gloves Increases the Density of Staphylococcus aureus in Patients with Hand Eczema.

Hand eczema is frequently colonized with Staphylococcus aureus. Some patients with hand eczema wear occlusive gloves regularly; however, the effect of this on the density of S. aureus is unexplored. The aim of this study is to examine the effect of occlusive gloves on the density of S. aureus sampled from the hands of patients with hand eczema. In an experimental set-up, patients with moderate-to-severe hand eczema wore an occlusive glove on one hand for 4 h with a 30-min break. Bacterial swabs were collected from the most severe eczema lesion on the hand before and immediately after glove exposure. S. aureus colony-forming units were counted and log-transformations used for comparison of before- and after-values. Among 30 patients, 19 (63%) were colonized with S. aureus. After glove occlusion S. aureus colony-forming units increased by a factor of 1.72 (p < 0.01). In conclusion, the density of sampled S. aureus on eczematous skin after prolonged wearing of occlusive gloves is greatly increased.

Dynamics of the Human Nasal Microbiota and Staphylococcus aureus CC398 Carriage in Pig Truck Drivers across One Workweek.

Drivers of pig trucks constitute a potential route of human transmission of livestock-associated methicillin-resistant Staphylococcus aureus clonal complex 398 (LA-MRSA CC398). In this study, we determined MRSA prevalence in pig truck drivers (n = 47) and monitored the nasal microbiota of 9 drivers 3 times daily throughout 1 workweek (n = 113 samples) and compared it to that of their spouses (n = 25 samples from 6 spouses) and 89 nonexposed subjects. S. aureus isolates (n = 232) derived from a subset of nasal and truck samples were whole-genome sequenced. The nasal alpha diversity of drivers in the beginning of the workday was lower than that of nonexposed subjects. During the workday, it increased significantly. Similarly, the drivers' nasal composition shifted during the workday, becoming increasingly different from that of their spouses and nonexposed individuals. Clustering into community state types (CSTs) revealed frequent switches from either S. aureus- or Corynebacterium-dominated CSTs in the mornings to a Psychrobacter-dominated CST during the workday. Six intermittent MRSA carriers were mostly MRSA negative in the mornings, and their nasal microbiota resembled that of nonexposed subjects. When acquiring MRSA during the workday, they switched to the Psychrobacter-dominated CST. In contrast, the nasal microbiota of two persistent MRSA carriers was dominated by staphylococci. In conclusion, we show that the nasal microbiota of pig truck drivers is very dynamic, undergoes drastic changes during workdays, and differs from that of nonexposed subjects even before pig contact. MRSA-carrying drivers may eventually introduce MRSA into the community and health care facilities. Carriage dynamics, however, showed that for most drivers, CC398 MRSA is rapidly lost and only rarely causes transmission to spouses. IMPORTANCE In Denmark, the number of human methicillin-resistant Staphylococcus aureus (MRSA) cases has increased dramatically since the early 2000s, starting from imported cases and spreading in the community. However, today, approximately one-third of all new cases are attributed to livestock-associated MRSA clonal complex 398 (LA-MRSA CC398). This mirrors the increase in pig farms, of which 95% are now positive for LA-MRSA, and this has been caused mainly by three dominant lineages enriched for a number of key antimicrobial resistance genes. Although most human LA-MRSA CC398 infections in Denmark are linked to livestock contact, still up to one-third are not. Pig truck drivers constitute a previously understudied occupation group which may transmit LA-MRSA CC398 to household members, the community, and hospitals. In this study, we demonstrate dramatic work-related changes in the nasal microbiota of pig truck drivers, as well as in their carriage of LA-MRSA CC398. However, they likely do not constitute an important reservoir for LA-MRSA CC398 dissemination.

Staphylococcal Communities on Skin Are Associated with Atopic Dermatitis and Disease Severity.

The skin microbiota of atopic dermatitis (AD) patients is characterized by increased Staphylococcus aureus colonization, which exacerbates disease symptoms and has been linked to reduced bacterial diversity. Skin bacterial communities in AD patients have mostly been described at family and genus levels, while species-level characterization has been limited. In this study, we investigated the role of the bacteria belonging to the Staphylococcus genus using targeted sequencing of the tuf gene with genus-specific primers. We compared staphylococcal communities on lesional and non-lesional skin of AD patients, as well as AD patients with healthy controls, and determined the absolute abundance of bacteria present at each site. We observed that the staphylococcal community, bacterial alpha diversity, and bacterial densities were similar on lesional and non-lesional skin, whereas AD severity was associated with significant changes in staphylococcal composition. Increased S. aureus, Staphylococcus capitis, and Staphylococcus lugdunensis abundances were correlated with increased severity. Conversely, Staphylococcus hominis abundance was negatively correlated with severity. Furthermore, S. hominis relative abundance was reduced on AD skin compared to healthy skin. In conclusion, various staphylococcal species appear to be important for skin health.

Identification of cutaneous fungi and mites in adult atopic dermatitis: analysis by targeted 18S rRNA amplicon sequencing.

BACKGROUND: Atopic dermatitis (AD) patients have an altered skin bacterial community, with an abundance of Staphylococcus aureus associated with flares, highlighting that microbial organisms may be important for disease exacerbation. Despite strong evidence of association between bacterial skin colonisation and AD, very limited knowledge regarding the eukaryotic microbial community, including fungi and ectoparasites, in AD exists. In this study, we compared the skin and nasal eukaryotic microbial community between adult AD patients (n = 55) and non-AD healthy controls (n = 45) using targeted 18S rRNA amplicon sequencing. Analysis was based on the presence or absence of eukaryotic microorganisms. RESULTS: The cutaneous composition of the eukaryotic microbial community and the alpha-diversity differed significantly between AD patients and non-AD individuals, with increased species richness on AD skin. Alpha-diversity and beta-diversity were similar on lesional and non-lesional skin of patients. The ectoparasite Demodex folliculorum and the yeast Geotrichum candidum were significantly more prevalent on the skin of AD patients. The prevalence of D. folliculorum on lesional skin was greater among patients recently treated with topical corticosteroid. Malassezia was one of the most frequently detected genera at all sites, with M. globosa and M. restricta being the most prevalent. M. restricta was under represented in the anterior nares of AD patients as compared to the non-AD control population. CONCLUSION: Significant differences in the eukaryotic microbial communities were found between AD patients and non-AD individuals, with the most striking finding being the significantly overrepresentation of D. folliculorum on AD skin. Whether D. folliculorum can contribute to skin inflammation in AD needs further investigation.