Rosacea is a common dermatological condition that predominantly affects the central regions of the face. Rosacea affects up to 3 % of the world's population and a number of subtypes are recognized. Rosacea can be treated with a variety of antibiotics (e.g. tetracycline or metronidazole) yet no role for bacteria or microbes in its aetiology has been conclusively established. The density of Demodex mites in the skin of rosacea patients is higher than in controls, suggesting a possible role for these mites in the induction of this condition. In addition, Bacillus oleronius, known to be sensitive to the antibiotics used to treat rosacea, has been isolated from a Demodex mite from a patient with papulopustular rosacea and a potential role for this bacterium in the induction of rosacea has been proposed. Staphylococcus epidermidis has been isolated predominantly from the pustules of rosacea patients but not from unaffected skin and may be transported around the face by Demodex mites. These findings raise the possibility that rosacea is fundamentally a bacterial disease resulting from the over-proliferation of Demodex mites living in skin damaged as a result of adverse weathering, age or the production of sebum with an altered fatty acid content. This review surveys the literature relating to the role of Demodex mites and their associated bacteria in the induction and persistence of rosacea and highlights possible therapeutic options.

Purpose-To investigate correlation between ocular Demodex infestation and serum.Design-A prospective study to correlate clinical findings with laboratory data.Participants-We consecutively enrolled 59 patients: 34 men and 25 women with a mean age of 60.4±17.6 years (range, 17-93).Methods-Demodex counting was performed based on lash sampling. Serum immunoreactivity to two 62-kDa and 83-kDa proteins derived from B oleronius was determined by Western blot analysis. Facial rosacea, lid margin, and ocular surface inflammation were documented by photography and graded in a masked fashion.Main Outcome Measures-Statistical significance based on correlative analyses of clinical and laboratory data.Results-These 59 patients were age matched, but not gender matched, regarding serum immunoreactivity, ocular Demodex infestation, or facial rosacea. There was a significant correlation between serum immunoreactivity and facial rosacea (P = 0.009), lid margin inflammation (P = 0.040), and ocular Demodex infestation (P = 0.048), but not inferior bulbar conjunctival inflammation (P = 0.573). The Demodex count was significantly higher in patients with positive facial rosacea (6.6±9.0 vs. 1.9±2.2; P = 0.014). There was a significant correlation of facial rosacea with lid margin inflammation (P = 0.016), but not with inferior bulbar conjunctival inflammation (P = 0.728). Ocular Demodex infestation was less prevalent in patients with aqueous tear-deficiency dry eye than those without (7/38 vs. 12/21; P = 0.002). Conclusions-The strong correlation provides a better understanding of comorbidity betweenDemodex mites and their symbiotic B oleronius in facial rosacea and blepharitis. Treatments directed to both warrant future investigation.

SummaryBackground Patients with rosacea demonstrate a higher density of Demodex mites in their skin than do controls. A bacterium isolated from a Demodex mite from a patient with papulopustular rosacea (PPR) was previously shown to provoke an immune response in patients with PPR or ocular rosacea, thus suggesting a possible role for bacterial proteins in the aetiology of this condition. Objectives To examine the response of neutrophils to proteins derived from a bacterium isolated from a Demodex mite. Methods Bacterial cells were lysed and proteins were partially purified by Ä KTA fast protein liquid chromatography. Isolated neutrophils were exposed to bacterial proteins and monitored for alterations in migration, degranulation and cytokine production. Results Neutrophils exposed to proteins from Bacillus cells demonstrated increased levels of migration and elevated release of matrix metalloprotease 9, an enzyme known to degrade collagen, and cathelicidin, an antimicrobial peptide. In addition, neutrophils exposed to the bacterial proteins demonstrated elevated rates of interleukin 8 and tumour necrosis factor-a production. Conclusions Proteins produced by a bacterium isolated from a Demodex mite have the ability to increase the migration, degranulation and cytokine production abilities of neutrophils. These results suggest that bacteria may play a role in the inflammatory erythema associated with rosacea.

The low quantum yield of luminescence in the NIR region of small (1.8 nm) gold nanoparticles stabilized with triphenylphosphine (TPP) increases by at least 2 orders of magnitude when TPP is replaced with a pyrene derivative. Very efficient energy transfer from the bound fluorophores to the gold core was observed, leading to a strong sensitized emission.

Summary Background  Rosacea is a chronic inflammatory condition that affects the skin of the face and the eyes. Erythematotelangiectatic rosacea is characterized by flushing, oedema and telangiectasia. Patients with rosacea demonstrate elevated densities of Demodex mites in their skin compared with controls. A bacterium (Bacillus oleronius) isolated from Demodex mites from a patient with papulopustular rosacea has been demonstrated to produce antigenic proteins that may play a role in papulopustular and ocular rosacea. Objectives  To establish whether there was a correlation between the reactivity of sera from patients with erythematotelangiectatic rosacea to Bacillus antigens, and to characterize the proteins to which these patients showed reactivity. Methods  Serum samples from patients with erythematotelangiectatic rosacea and controls were examined for reactivity to Bacillus proteins by Western blot analysis. Proteins to which the sera reacted were excised from gels, trypsin digested, and putative identities were assigned following liquid chromatography‐mass spectrometry (LC‐MS) analysis. Results  Eighty per cent (21/26) of patients with erythematotelangiectatic rosacea showed serum reactivity to the 62‐ and 83‐kDa proteins of B. oleronius, compared with 40% (9/22) of controls (P = 0·004). The 62‐kDa protein was characterized by LC‐MS and showed homology to groEL chaperonin, which provokes a strong immune response in mammals. The 83‐kDa protein showed homology to aconitate hydratase, of which expression is increased in bacteria under oxidative stress, and which is highly immunogenic. Conclusions  The majority of patients with erythematotelangiectatic rosacea show serum reactivity to two proteins from B. oleronius, suggesting that this bacterium may play a role in the induction of this condition. The two proteins to which patient sera reacted were found to be similar to a heat shock protein and an enzyme involved in regulating the stress response of the bacterium.

The results indicate that exposure of corneal epithelial cells to Bacillus proteins results in an aberrant wound healing response as visualized using a scratch wound assay. These results suggest a possible link between the high density of Demodex mites on the eyelashes of ocular rosacea patients and the development of corneal ulcers.

Rosacea is a chronic inflammatory condition that affects the skin of the face and the eyes. The aetiology of rosacea is not clearly established but increasing evidence suggests a potential role for bacteria in the induction of the condition. A role for Bacillus oleronius, originally isolated from within a Demodex folliculorum mite, in the aetiology of the condition has been suggested. The aim of the study was to determine whether a correlation existed between the level of sebum and the density of D. folliculorum in the skin of erythematotelangiectatic rosacea patients, and the reactivity of these patients' sera to proteins of B. oleronius. Serum reactivity to the 62 and 83 kDa B. oleronius proteins was found in 82.6 % (62/75) of the rosacea patients and in 26.9 % (14/52) of controls (P50.0016). In the group of rosacea patients whose sera reacted to B. oleronius proteins, the level of sebum was statistically lower than in controls (P50.01). The density of D. folliculorum on the face of Bacillus positive rosacea patients was statistically higher than controls (P50.0001). Rosacea patients demonstrated increased Demodex populations on their faces and reduced sebum levels. Their sera also showed reactivity to B. oleronius proteins, suggesting a potential role for this bacterium in the aetiology of rosacea.

Secretory leukoprotease inhibitor (SLPI) is an anti-inflammatory protein present in respiratory secretions. Whilst epithelial cell SLPI is extensively studied, neutrophil associated SLPI is poorly characterised. Neutrophil function including chemotaxis and degranulation of proteolytic enzymes involves changes in cytosolic calcium (Ca2+) levels which is mediated by production of inositol 1,4,5-triphosphate (IP3) in response to G-protein-coupled receptor (GPCR) stimuli. The aim of this study was to investigate the intracellular function of SLPI and the mechanism-based modulation of neutrophil function by this antiprotease. Neutrophils were isolated from healthy controls (n = 10), individuals with cystic fibrosis (CF) (n = 5) or chronic obstructive pulmonary disease (COPD) (n = 5). Recombinant human SLPI significantly inhibited fMet-Leu-Phe (fMLP) and interleukin(IL)-8 induced neutrophil chemotaxis (P < 0.05) and decreased degranulation of matrix metalloprotease-9 (MMP-9), hCAP-18, and myeloperoxidase (MPO) (P < 0.05). The mechanism of inhibition involved modulation of cytosolic IP3 production and downstream Ca2+ flux. The described attenuation of Ca2+ flux was overcome by inclusion of exogenous IP3 in electropermeabilized cells. Inhibition of IP3 generation and Ca2+ flux by SLPI may represent a novel anti-inflammatory mechanism, thus strengthening the attractiveness of SLPI as a potential therapeutic molecule in inflammatory airway disease associated with excessive neutrophil influx including CF, non-CF bronchiectasis, and COPD.