Microbiology of hidradenitis suppurativa (acne inversa): a histological study of 27 patients

Hidradenitis suppurativa (acne inverse) (HS) is a chronic skin disease primarily affecting hair follicles. The aetiology of HS is unknown, but infection is believed to play some role. This retrospective study investigated the microbial colonization directly in skin appendices in HS skin samples. Archival samples from 27 patients with HS were screened by immunofluorescence labelling with monoclonal and polyclonal antibodies against Gram‐positive bacteria, Propionibacterium acnes and Propionibacterium granulosum. Fluorescence in situ hybridization was used for further species identification of Staphylococcus spp. Overall, 17 patients (63%) were found positive for bacterial colonization. Of these, 15 showed colonization in hair follicles and/or sinus tracts. The most commonly identified bacteria were DAPI labelled coccoids that were seen in 71% of the positive patients in the form of biofilms and microcolonies. P. acnes was found as biofilms in hair follicles of two patients. Staphylococcus aureus and coagulase‐negative staphylococci were not detected in any sample. The results of this study indicate a common bacterial presence in HS skin lesions. Bacterial biofilms are not uncommon and their pathogenic role needs further evaluation.     

Acne is not associated with yet-uncultured bacteria

Current clinical and microbiological information on acne fails to demonstrate a clear association between particular species, including Propionibacterium acnes, and disease, and the disease continues to be a considerable problem. To test if acne is associated with hitherto uncultured bacteria residing in diseased skin follicles, sequencing and phylogenetic analysis of approximately 5,700 amplified and cloned 16S rRNA genes were used to determine the microbial diversity in follicles from acne patients and healthy individuals and from the superficial skin of acne patients. Follicles from healthy skin were exclusively colonized by P. acnes, whereas the follicular microbiota of acne patients included, in addition, Staphylococcus epidermidis and minor proportions of other species. In comparison, samples from superficial skin showed a complex microbiota represented by 12 to 16 bacterial species. The findings of the study exclude the possibility that acne is associated with yet-uncultured bacteria and shows that healthy skin follicles constitute a remarkably exclusive habitat allowing colonization only by P. acnes.     

Propionibacterium acnes activates caspase‐1 in human neutrophils

Propionibacterium acnes is a Gram‐positive, slow‐growing, anaerobic bacillus, predominantly found as a commensal on the skin and mucous membranes of adults. It is, however, also considered an opportunistic pathogen; mostly associated with acne vulgaris, but rarely also with severe infections such as infective endocarditis, prosthetic joint infections, and deep sternal wound infections following cardiothoracic surgery. In addition, P. acnes has recently been found in high frequency in prostate tissue from patients with prostatitis and prostate cancer. The NOD‐like receptors (NLR) act as intracellular sensors of microbial components, and a number of various bacteria have been found to induce assembling and activation of NLR‐inflammasomes; leading to a pro‐inflammatory response. The inflammasome‐mediated formation of the pro‐inflammatory cytokines interleukin‐1β (IL‐1β) and IL‐18 involves the auto‐proteolytic maturation of caspase‐1. This study investigated if P. acnes activates inflammasomes. Propionibacterium acnes isolates (n = 29) with diverse origin were used as stimuli for peripheral leukocytes obtained from blood donors (BDs). The activity of inflammasomes was determined by measuring caspase‐1 by flow cytometry and cytokine production by ELISA. A significant amount of caspase‐1 was found in neutrophils upon P. acnes stimulation, whereas only a modest activation was seen in monocytes. The activation was mainly produced by components of the bacterial cell and no exo‐products, because heat‐killed and live bacteria caused high activation of caspase‐1 as well as cytokine production, whereas the bacterial supernatant elicited minor effect. The response among different BDs varied significantly, almost fivefold. In addition, P. acnes of various origins showed considerable variation, however, the commensal isolates showed a stronger response compared with the invasive. In conclusion, although regarded as a harmless commensal of the skin, P. acnes strongly activates the inflammasome of human peripheral neutrophils.     

Increased prevalence and altered species composition of filamentous fungi in respiratory specimens from cystic fibrosis patients

Filamentous fungi cultured from respiratory tract specimens submitted to the department of clinical microbiology, Aarhus University Hospital, during 2010 were identified by morphology and by internal transcribed spacer (ITS) sequencing. Of 343 fungal isolates, discrepancies between identification methods were observed for four isolates (1.2%), while identification to species was achieved only with ITS sequencing for 16 isolates (4.7%). Filamentous fungi were isolated from 15% of cystic fibrosis (CF) respiratory samples in contrast to 2% of non‐CF samples. From CF patients, a total of nine different species were found in 188 samples from 48 patients, whereas from non‐CF patients, 24 different species were found in 155 samples from 111 patients. CF was associated with a significant overrepresentation of Aspergillus fumigatus and Scedosporium species; in contrast, the frequency of Penicillium spp. and other putative contaminants were significantly increased in non‐CF patients. The altered species variation of filamentous fungi in CF respiratory specimens is contradictory to a scenario of incidentally inhaled spores, trapped in the viscous airway mucus of these patients and subsequently expectorated; rather, our data most likely reflect both an increased prevalence and an increased proportion of truly colonizing fungi in this patient group.     

Duplex detection of the Mycobacterium tuberculosis complex and medically important non‐tuberculosis mycobacteria by real‐time PCR based on the rnpB gene

A duplex real‐time PCR based on the rnpB gene was developed for Mycobacterium spp. The assay was specific for the Mycobacterium tuberculosis complex (MTB) and also detected all 19 tested species of non‐tuberculous mycobacteria (NTM). The assay was evaluated on 404 clinical samples: 290 respiratory samples and 114 from tissue and other non‐respiratory body sites. M. tuberculosis was detected by culture in 40 samples and in 30 samples by the assay. The MTB assay showed a sensitivity similar to Roche Cobas Amplicor MTB‐PCR (Roche Molecular Systems, Pleasanton, CA, USA). There were only nine samples with non‐tuberculous mycobacteria detected by culture. Six of them were detected by the PCR assay.     

Pathogenesis of acne

Acne vulgaris is a skin disorder of the sebaceous follicles that commonly occurs in adolescence and in young adulthood. The major pathogenic factors involved are hyperkeratinization, obstruction of sebaceous follicles resulting from abnormal keratinization of the infundibular epithelium, stimulation of sebaceous gland secretion by androgens, and microbial colonization of pilosebaceous units by Propionibacterium acnes, which promotes perifollicular inflammation. The clinical presentation of acne can range from a mild comedonal form to severe inflammatory cystic acne of the face, chest, and back. At the ultrastruc-tural level, follicular keratinocytes in comedones can be seen to possess increased numbers of desmosomes and tonofilaments, which result in ductal hypercornification. The increased activity of sebaceous glands elicited by androgen causes proliferation of P. acnes, an anaerobe present within the retained sebum in the pilosebaceous ducts. The organism possesses a ribosome-rich cytoplasm and a relatively thick cell wall, and produces several biologically active mediators that may contribute to inflammation, for instance, by promoting leukocyte migration and follicular rupture. In inflamed lesions, numerous neutrophils and macrophages infiltrate around hair follicles and sometimes phagocytose P. acnes. To examine the participation of neurogenic factors in the pathogenesis of acne, we quantitatively assessed the effects of neuropeptides on the morphology of sebaceous glands in vitro using electron microscopy. Substance P, which can be elicited by stress, promoted the development of cytoplasmic organelles in sebaceous cells, stimulated sebaceous germinative cells, and induced significant increases in the area of sebaceous glands. It also increased the size of individual sebaceous cells and the number of sebum vacuoles for each differentiated sebaceous cell, all of which suggests that substance P promotes both the proliferation and the differentiation of sebaceous glands. In this review, we introduce the general concept of pathogenic factors involved in acne, including typical electron microscopic findings and recent evidence of stress-induced exacerbation of acne from a neurological point of view. An improved understanding of the pathogenesis of acne should lead to a rational therapy to successfully treat this skin disease.     

Low colonization rates of Clostridium difficile among patients and healthcare workers at Örebro University Hospital in Sweden

The aim of this study was to investigate the rate of asymptomatic colonization rate of Clostridium difficile among both healthcare workers (HCWs) and patients in a hospital ward in Sweden. In a prospective observational study, asymptomatic HCWs (n = 22) (22/60; 37%) attending patients in an infectious disease ward in Sweden participated and were screened once for C. difficile. At the same time, 58 consecutive patients (58/227; 26%) admitted to the same ward were screened for C. difficile, first at admission and thereafter two times weekly. Fecal samples were obtained by rectal swabs and cultured anaerobically using both cycloserine‐cefoxitin‐fructose agar and enrichment (Cooked Meat broth). All samples were also tested by loop‐mediated isothermal amplification and isolates were tested for the presence of toxin A or B by enzyme immunoassay. None of the analyzed fecal samples from HCWs contained C. difficile. Among the patients during a 2‐month observational period, three of the 58 patients (5.2%) were culture positive regarding C. difficile on admission and one additional patient became asymptomatically colonized with C. difficile during the hospital stay. Thus, the colonization rates were 0% (0/22) (95% confidence interval (CI): 0–15.4%) among HCWs and 5.2% (3/58) (95% CI: 1.1–14.4%) among patients at admission. As the HCWs were screened only once, we have not studied transient colonization. In conclusion, with observed low colonization rates, we find no support that HCWs would be an important source for C. difficile transmission.     

Disordered Toll‐like receptor 2 responses in the pathogenesis of pulmonary sarcoidosis

In this study, we hypothesized that the granulomatous disorder sarcoidosis is not caused by a single pathogen, but rather results from abnormal responses of Toll‐like receptors (TLRs) to conserved bacterial elements. Unsorted bronchoalveolar lavage (BAL) cells from patients with suspected pulmonary sarcoidosis and healthy non‐smoking control subjects were stimulated with representative ligands of TLR‐2 (in both TLR‐2/1 and TLR‐2/6 heterodimers) and TLR‐4. Responses were determined by assessing resulting production of tumour necrosis factor (TNF)‐α and interleukin (IL)‐6. BAL cells from patients in whom sarcoidosis was confirmed displayed increased cytokine responses to the TLR‐2/1 ligand 19‐kDa lipoprotein of Mycobacterium tuberculosis (LpqH) and decreased responses to the TLR‐2/6 agonist fibroblast stimulating ligand‐1 (FSL)‐1. Subsequently, we evaluated the impact of TLR‐2 gene deletion in a recently described murine model of T helper type 1 (Th1)‐associated lung disease induced by heat‐killed Propionibacterium acnes. As quantified by blinded scoring of lung pathology, P. acnes‐induced granulomatous pulmonary inflammation was markedly attenuated in TLR‐2^–/– mice compared to wild‐type C57BL/6 animals. The findings support a potential role for disordered TLR‐2 responses in the pathogenesis of pulmonary sarcoidosis.     

Propionibacterium acnes overabundance and natural killer group 2 member D system activation in corpus‐dominant lymphocytic gastritis

Corpus‐dominant lymphocytic gastritis (LyG) is characterized by CD8⁺ T‐cell infiltration of the stomach epithelium by a so far uncharacterized mechanism. Although Helicobacter pylori is typically undetectable in LyG, patients respond to H. pylori antibiotic eradication therapy, suggesting a non‐H. pylori microbial trigger for the disease. Comparative microbiota analysis of specimens from LyG, H. pylori gastritis and healthy controls precluded involvement of H. pylori in LyG but identified Propionibacterium acnes as a possible disease trigger. In addition, the natural killer group 2 member D (NKG2D) system and the proinflammatory cytokine interleukin (IL)‐15 are significantly upregulated in the gastric mucosa of LyG patients, and gastric epithelial cells respond to microbe‐derived stimuli, including live P. acnes and the microbial products short‐chain fatty acids, with induction of NKG2D ligands. In contrast, H. pylori infection does not activate or even repress NKG2D ligands. Together, our findings identify P. acnes as a possible causative agent for LyG, which is dependent on the NKG2D system and IL‐15 activation. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Prevalence of Acanthamoeba and superbugs in a clinical setting: coincidence or hyperparasitism?

Antibacterial strategies to eradicate superbugs from hospitals/nursing homes have had limited success, suggesting the need for employing innovative preventative measures and better understanding of the prevalence of microbial pathogens in close proximity of susceptible populations. A total of 120 environmental samples were collected from the Aga Khan University hospital. Amoebae were identified using morphological characteristics as well as PCR using genus-specific primers, while bacteria were identified using standard biochemical testing. Out of 120 samples tested, 52 (43.3 %) samples were positive for Acanthamoeba, while all 120 (100 %) samples were positive for bacteria. Following bacterial identification, samples showed mixed bacterial populations. Out of 120 samples, 76 (63.3 %) samples were positive for Bacillus spp., 64 (53.3 %) samples were positive for Corynebacterium spp., 32 (26.6 %) samples were positive for Staphylococcus spp., and 9 (7.5 %) samples were positive for Micrococcus spp. The antibiotic susceptibility showed that all bacterial isolates recovered were multiple drug-resistant. The current findings suggest that Acanthamoeba and bacteria coexist in a clinical environment. Given that Acanthamoeba can harbor bacteria, anti-amoebic approaches may represent a strategy in eradicating “superbugs” from the clinical setting in addition to the current measures.     

Simultaneous testing of immunological sensitization to multiple antigens in sarcoidosis reveals an association with inorganic antigens specifically related to a fibrotic phenotype

Organic and inorganic antigens were studied simultaneously in the same cohort of sarcoidosis patients to investigate whether correlations between clinical characteristics and immunological sensitization could reveal new phenotypes. Sensitization to antigens of mycobacteria, Propionibacterium acnes catalase and vimentin was investigated in 201 sarcoidosis and 51 obstructive sleep apnoea patients, serving as control group. Sensitization to aluminium, beryllium, silica and zirconium was also studied in 105 of the sarcoidosis patients and in 24 of the controls. A significantly higher percentage of sarcoidosis patients (27·6%) than controls (4·2%) had an immunological response to metals or silica (P = 0·014). A higher percentage of these sarcoidosis patients showed fibrosis on chest X‐ray 5 years after the diagnosis (69·2 versus 30·3%, P = 0·016). No significant differences in mycobacterial or vimentin enzyme‐linked immunospot (ELISPOT) assay results were observed between sarcoidosis and control patients. A significantly lower percentage of sarcoidosis patients (3·5%) than control patients (15·7%) had a positive ELISPOT for P. acnes catalase (P = 0·003). However, sarcoidosis patients sensitized to P. acnes catalase were more likely to have skin involvement, while sarcoidosis patients sensitized to mycobacterial antigens were more likely to have cardiac involvement. Our study suggests a more prominent role for inorganic triggers in sarcoidosis pathogenesis than previously thought. Immunological sensitization to inorganic antigens was associated with development of fibrotic sarcoidosis. No association was found between sensitization to bacterial antigens or vimentin and sarcoidosis in Dutch patients. However, our data suggest that trigger‐related phenotypes can exist in the heterogeneous population of sarcoidosis patients.     

Intestinal macrophages: unique effector cells of the innate immune system

Summary: The gastrointestinal mucosa is the largest reservoir of macrophages in the body. These important effector cells are derived from blood monocytes that are recruited to the lamina propria by endogenous chemoattractants in the non‐inflamed mucosa and by inflammatory chemokines and bacterial products during inflammation. In the non‐inflamed mucosa, newly recruited pro‐inflammatory monocytes are exposed to lamina propria stromal (extracellular matrix) factors that induce phenotypic and functional differentiation into non‐inflammatory macrophages. As a consequence of this differentiation, resident lamina propria macrophages are strikingly downregulated for the expression of innate response receptors, such as the receptors for lipopolysaccharide, immunoglobulin G (IgG), and IgA, and the production of pro‐inflammatory cytokines, including interleukin‐1 (IL‐1), IL‐6, IL‐8, and tumor necrosis factor‐α. Despite downregulated pro‐inflammatory function, strong phagocytic and bactericidal activities remain intact. Thus, in the non‐inflamed intestinal mucosa, lamina propria macrophages are non‐inflammatory but retain avid scavenger and host defense functions, a unique but ideal phenotype and functional profile for effector cells in close proximity to immunostimulatory microorganisms and products.     

Isolation and characterization of heavy‐metal resistant microbes from roadside soil and phylloplane

Contamination by heavy metals is one of the major environmental problems in many countries and these contaminants reach from various sources such as traffic cars and other activities. Soil and phylloplane samples were collected from eight traffic and two non‐traffic sites in Sohag city, Egypt. Heavy metal contents of Cd²⁺, Zn²⁺ and Pb²⁺ of soil and phylloplane samples were determined and revealed high levels of Zn²⁺ and Pb²⁺ in traffic samples. A total of 112 bacterial and 62 fungal isolates were obtained from soil and phylloplane. Bacterial isolates were characterized on the basis of morphological, physicochemical and biochemical characteristics; and 16S rRNA gene sequences. Fungal isolates were identified according to morphological characterization. Minimal inhibitory concentrations (MICs) of Cd²⁺, Zn²⁺ and Pb²⁺ for each isolate were detected. All bacterial and fungal isolates demonstrated resistance to lead with MICs >0.528 mM and >0.211, respectively. Moreover, the maximum MICs of cadmium and zinc for bacteria were 0.821 mM and 1.471 mM, respectively, where as, MICs for fungi were 0.328 mM and 0.588 mM, respectively. The most resistant bacterial and fungal isolates were Pseudomonas aeruginosa RA65 and Penicillium corylophyllum, respectively. Therefore, P. aeruginosa RA65 was selected for further investigations. Growth curve study showed that 0.264 mM lead had no efficiently effect on the growth of P. aeruginosa RA65. Plasmid isolation evidenced by transformation studies indicated that P. aeruginosa RA65 harbored a single plasmid (～9.5 kb) which mediated heavy meal resistance. Consequently, these microbial isolates could be potentially used in bioremediation of heavy metal‐contaminated environment. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Innate,antigen‐independent role for T cells in the activation of the immune system by Propionibacterium acnes

Propionibacterium acnes is a human commensal but also an opportunistic pathogen. In mice, P. acnes exerts strong immunomodulatory activities, including formation of intrahepatic granulomas and induction of LPS hypersensitivity. These activities are dependent on P. acnes recognition via TLR9 and subsequent IL‐12‐mediated IFN‐γ production. We show that P. acnes elicits IL‐12p40 and p35 mRNA expression in macrophages, and IFN‐γ mRNA in liver CD4⁺ T cells and NK cells. After priming with P. acnes, CD4⁺ T cells serve as the major IFN‐γ mRNA source. In the absence of CD4⁺ T cells, CD8⁺ T cells (regardless of antigenic specificity) or NK cells can produce sufficient IFN‐γ to induce the P. acnes‐driven immune effects. Moreover, in the absence of αβT cells, γδT cells also enable the development of strongly enhanced TNF‐α and IFN‐γ responses to LPS and intrahepatic granuloma formation. Thus, under microbial pressure, different T‐cell types, independent of their antigen specificity, exert NK‐cell‐like functions, which contribute decisively to the activation of the innate immune system.     

Molecular pathology of endometrial carcinoma

This review paper discusses the main molecular alterations of endometrial carcinoma, the most common cancer of the female genital tract. Two clinicopathological variants are recognized: the oestrogen‐related (type I, endometrioid carcinoma) and the non‐oestrogen‐related (type II, non‐endometrioid carcinoma). Whereas type I shows microsatellite instability and mutations in PTEN, PIK3CA, K‐RAS and CTNNB1 (beta‐catenin), type II exhibits TP53 mutations and chromosomal instability. Recent investigations regarding the role of non‐coding RNA have provided important information regarding tumour progression. Understanding pathogenesis at the molecular level is essential for identifying biomarkers of potential use in targeted therapies.     

Fungal colonization and/or infection in non-neutropenic critically ill patients: results of the EPCAN observational study

The purpose of this paper is to determine the incidence of fungal colonization and infection in non-neutropenic critically ill patients and to identify factors favoring infection by Candida spp. A total of 1,655 consecutive patients (>18 years of age) admitted for ≥7 days to 73 medical-surgical Spanish intensive care units (ICUs) participated in an observational prospective cohort study. Surveillance samples were obtained once a week. One or more fungi were isolated in different samples in 59.2% of patients, 94.2% of which were Candida spp. There were 864 (52.2%) patients with Candida spp. colonization and 92 (5.5%) with proven Candida infection. In the logistic regression analysis risk factors independently associated with Candida spp. infection were sepsis (odds ratio [OR] = 8.29, 95% confidence interval [CI] 5.07–13.6), multifocal colonization (OR = 3.49, 95% CI 1.74–7.00), surgery (OR = 2.04, 95% CI 1.27–3.30), and the use of total parenteral nutrition (OR = 4.37, 95% CI 2.16–8.33). Patients with Candida spp. infection showed significantly higher in-hospital and intra-ICU mortality rates than those colonized or non-colonized non-infected (P < 0.001). Fungal colonization, mainly due to Candida spp., was documented in nearly 60% of non-neutropenic critically ill patients admitted to the ICU for more than 7 days. Proven candidal infection was diagnosed in 5.5% of cases. Risk factors independently associated with Candida spp. infection were sepsis, multifocal colonization, surgery, and the use of total parenteral nutrition.     

Temporal variations in early gut microbial colonization are associated with allergen‐specific immunoglobulin E but not atopic eczema at 2 years of age

Background Intestinal microbiota undergoes substantial development during the first 2 years of life, important for intestinal immunologic development and maturation influencing systemic immune responses. Objective We aimed to investigate, using a prospective study design, whether allergen‐specific IgE (sIgE) and atopic eczema are associated with variations in gut microbial colonization patterns in an unselected population during the first 2 years of life. Methods Faeces from 94 infants were repeatedly sampled from 10 days, 4 months, 1 and 2 years postnatal and analysed for 12 different bacterial species by quantitative real‐time PCR. Venous blood samples from the infants were collected at 2 years of age and were analysed for sIgE for 12 specific allergens. The temporal gut colonization patterns for 42 sIgE‐positive (sIgE?0.35 kU/L) and 52 sIgE‐negative children (sIgE<0.1 kU/L) were then compared. The association between colonization pattern and phenotype as atopic eczema according to UK Working Party (UKWP) criteria were also described. Results Subjects with atopic sensitization had lower levels of Escherichia coli at 4 months and 1 year, higher levels of Bifidobacterium longum at 1 year and lower levels of Bacteroides fragilis at 2 years. For E. coli and B. longum, the differences were only transient and had disappeared by 2 years of age. For other species, there were no differences in colonization patterns, and we found no association between colonization pattern and atopic eczema. Conclusions and Clinical Relevance We found temporal and transient variations in gut microbial colonization patterns associated with differences in sIgE sensitization at 2 years of age. A full understanding of the principles and mechanisms that underlie intestinal microbial colonization and diversity and host–microbiota relationships will be pivotal for the development of therapeutic approaches that manipulate the intestinal microbiota to maintain human health. [Registration number: ISRCTN28090297] Cite this as: O. Storrø, T. Øien, Ø. Langsrud, K. Rudi, C. Dotterud and R. Johnsen, Clinical & Experimental Allergy, 2011 (41) 1545–1554.     

No link between rosacea and Propionibacterium acnes

Rosacea is a common skin disease in adults affecting mainly the facial skin. Although inflammation appears to play a pathogenic role in rosacea, initiating factors are largely unknown. Microbial involvement in the development of rosacea has been suggested previously. We aimed to visualize Propionibacterium acnes in the skin compartments of rosacea patients. Facial skin biopsies from 82 rosacea patients and 25 controls were stained with a P. acnes‐specific monoclonal antibody (QUBPa3). Seven of 82 patients (8.5%) tested positive for P. acnes which was present either as a biofilm (57% of positive) or a microcolony (43%) in colonized patients. Our results suggest that P. acnes does not play a major role in the pathogenesis of rosacea.