Staphylococcus epidermidis augments human ß-defensin-3 synthesis through the transforming growth factor alpha-epidermal growth factor receptor cascade.

BACKGROUND: Epidermal growth factor receptor inhibitors (EGFRIs) reduce ß-defensin 3 (BD3) from keratinocytes stimulated by S. epidermidis, potentially leading to the development of acneiform rashes in patients undergoing EGFRIs treatment. However, the mechanism through which S. epidermidis induces BD3 via EGFR remains incompletely understood. OBJECTIVE: To elucidate the BD3 production pathway triggered by S. epidermidis. METHODS: To assess the impact of S. epidermidis on EGFR ligand expression, the levels of released EGFR ligands in the keratinocyte culture medium following S. epidermidis stimulation were quantified using ELISA. Subsequently, to confirm the synergistic effect of TGF-α and S. epidermidis, we administered S. epidermidis and TGF-α to the keratinocyte culture medium and measured the expression levels of BD3. In addition, we stimulated Toll-like receptor 2 (TLR2)-knockdown keratinocytes with S. epidermidis and measured the expression levels of TGF-α. RESULTS: While S. epidermidis did not induce EGF and HB-EGF, they increased TGF-α. The expression of BD3 was higher in keratinocytes stimulated by S. epidermidis in the presence of TGF-α, as compared to its absence. Moreover, both S. epidermidis- and TGF-α-induced BD3 were significantly suppressed by cetuximab. The expression levels of TGF-α induced by S. epidermidis were reduced in TLR2-knockdown keratinocytes CONCLUSION: Our findings suggest that S. epidermidis induces the expression of TGF-α in keratinocytes through TLR2, which, in cooperation with TGF-α, stimulates the production of BD3.

Effective use of skin microbiome signatures for fingerprint identification.

BACKGROUND: Recent advances have increased the importance of the human microbiome, including the skin microbiome. Despite the hand microbiome research, the factors affecting the composition of the hand microbiome and their personal characteristics are incompletely known. OBJECTIVES: Despite changing environmental factors and personal variation, we aimed to indicate the interpersonal distinction between skin microbiota using simple and rapid molecular methods. METHODS: Over a non-consecutive 10-day period, samples were taken from 10 adult individuals, and ribotyping analysis of the 16S and 23S genes of S. epidermidis was performed on each skin sample. Additionally, EcoRI and HindIII enzyme reactions and variable number tandem repeat (VNTR) reactions of S. epidermidis obtained from DNA samples were performed. The skin microbiomes of individuals were evaluated along with the microbiome profiles left on the surfaces they touched. RESULTS: In the environmental samples taken, it has been observed that people preserve their core skin microbiota characters and carry them to their environment. It was determined that the highest similarity rate was 77.14%, and the lowest similarity rate was 31.74%. CONCLUSION: Our study showed that the core skin microbiota retains its characteristics and leaves traces in environments. The fact that the personal microbiome remains unchanged despite environmental differences and has characteristic features has shown that it can be used in forensic sciences to distinguish individuals from each other. These results with simple and rapid methods further increased the importance and significance of the study. The findings indicate that personal skin microbiota can provide a significant contribution to criminal investigations by increasing accuracy and reliability, especially in forensic analyses.

Staphylococcus epidermidis biofilm in inflammatory breast cancer and its treatment strategies.

Bacterial biofilms represent a significant challenge in both clinical and industrial settings because of their robust nature and resistance to antimicrobials. Biofilms are formed by microorganisms that produce an exopolysaccharide matrix, protecting function and supporting for nutrients. Among the various bacterial species capable of forming biofilms, Staphylococcus epidermidis, a commensal organism found on human skin and mucous membranes, has emerged as a prominent opportunistic pathogen, when introduced into the body via medical devices, such as catheters, prosthetic joints, and heart valves. The formation of biofilms by S. epidermidis on these surfaces facilitates colonization and provides protection against host immune responses and antibiotic therapies, leading to persistent and difficult-to-treat infections. The possible involvement of biofilms for breast oncogenesis has recently created the curiosity. This paper therefore delves into S. epidermidis biofilm involvement in breast cancer. S. epidermidis biofilms can create a sustained inflammatory environment through their metabolites and can break DNA in breast tissue, promoting cellular proliferation, angiogenesis, and genetic instability. Preventing biofilm formation primarily involves preventing bacterial proliferation using prophylactic measures and sterilization of medical devices and equipment. In cancer treatment, common modalities include chemotherapy, surgery, immunotherapy, alkylating agents, and various anticancer drugs. Understanding the relationship between anticancer drugs and bacterial biofilms is crucial, especially for those undergoing cancer treatment who may be at increased risk of bacterial infections, for improving patient outcomes. By elucidating these interactions, strategies to prevent or disrupt biofilm formation, thereby reducing the incidence of infections associated with medical devices and implants, can be identified.

The impact of oxygen content on Staphylococcus epidermidis pathogenesis in ocular infection based on clinical characteristics, transcriptome and metabolome analysis.

Introduction: This study aims to delineate the etiology and prevalence of isolated pathogens, along with the clinical characteristics of endophthalmitis patients over a 9-year period at hospital in Southwest of China. Additionally, we investigating the metabolic and cellular processes related to environmental factors may offer novel insights into endophthalmitis. Methods: We analyzed data pertaining to endophthalmitis patients treated at the Affiliated Hospital of Yunnan University from 2015 to 2023. According to our clinical data, we conducted an experiment based on transcriptomics and metabolomics analysis to verify whether environmental factors affect behavior of S. epidermidis by culturating S. epidermidis under oxic and microoxic condition. Results: In this study, 2,712 fungi or bacteria strains have been analyzed, gram-positive bacteria constituted 65.08%, with S. epidermidis being the most predominant species (25.55%). Ophthalmic trauma was the primary pathogenic factor for S. epidermidis ocular infections. Regarding fluoroquinolones, S. epidermidis exhibited the higher resistance rate to levofloxacin than moxifloxacin. Moreover, our investigation revealed that S. epidermidis in microoxic environment increase in energy metabolism, amino acid metabolism, and membrane transport. Conclusion: Our findings underscore the significance of S. epidermidis as a crucial pathogen responsible for infectious endophthalmitis. It is crucial to exercise vigilance when considering Levofloxacin as the first-line drug for empiric endophthalmitis treatment. The metabolites alteration observed during the commensal-to-pathogen conversion under microoxic condition serve as a pivotal environmental signal contributing to S. epidermidis metabolism remodeling, toward more pathogenic state.

Determining the dispersion time in Staphylococcus epidermidis biofilm using physical and molecular approaches.

Despite being an innocuous commensal of human skin and mucous membranes, Staphylococcus epidermidis, infects surgical wounds and causes infections through biofilm formation. This study evaluates, in a time-dependent experiment, the self-dispersion of S. epidermidis CIP 444 biofilm when formed on borosilicate glass (hydrophilic) and polystyrene (hydrophobic) surfaces, using physical and molecular approaches. During a seven-day period of incubation, absorbance measurement revealed a drop in biofilm optical density on both studied surfaces on day 4 (0.043-0.035 nm/cm2, polystyrene), (0.06-0.053 nm/cm2, borosilicate glass). Absorbance results were correlated with crystal violet staining that showed a clear detachment from day 4. The blue color increases again on day 7, with an increase in biofilm optical density indicating the regeneration of the biofilm. Changes in gene expression in the S. epidermidis biofilm were assessed using a real-time reverse transcription-polymerase chain reaction. High expression of agr genes was detected on days 4 and 5, confirming our supposition of dispersion in this period, autolysin genes like atlE1 and aae were upregulated from day 3 until day 6 and the genes responsible for slime production and biofilm accumulation, were upregulated on days 4, 5, and 6 (ica ADBC) and on days 5, 6 and 7 (aap), indicating a dual process taking place. These findings suggest that S. epidermidis CIP 444 biofilms disperse at day 4 and reform at day 7. Over the course of the seven-day investigation, 2-ΔΔCt results showed that some genes in the biofilm were dramatically enhanced while others were significantly decreased as compared to planktonic ones.

Novel 3D printed polysaccharide-based materials with prebiotic activity for potential treatment of diaper rash.

Diaper rash, mainly occurring as erythema and itching in the diaper area, causes considerable distress to infants and toddlers. Increasing evidence suggests that an unequal distribution of microorganisms on the skin contributes to the development of diaper dermatitis. Probiotic bacteria, like Staphylococcus epidermidis, are crucial for maintaining a healthy balance in the skin's microbiome, among others, through their fermentative metabolites, such as short-chain fatty acids. Using a defined prebiotic as a carbon source (e.g., as part of the diaper formulation) can selectively trigger the fermentation of probiotic bacteria. A proper material choice can reduce diaper rash incidence by diminishing the skin exposure to wetness and faeces. Using 3D printing, we fabricated carbon-rich materials for the top sheet layer of baby diapers that enhance the probiotic activity of S. epidermidis. The developed materials' printability, chemical composition, swelling ability, and degradation rate were analysed. In addition, microbiological tests evaluated their potential as a source of in situ short-chain fatty acid production. Finally, biocompatibility testing with skin cells evaluated their safety for potential use as part of diapers. The results demonstrate a cost-effective approach for producing novel materials that can tailor the ecological balance of the skin microflora and help treat diaper rash.

Quantifying the Dynamics of Bacterial Biofilm Formation on the Surface of Soft Contact Lens Materials Using Digital Holographic Tomography to Advance Biofilm Research.

The increase in bacterial resistance to antibiotics in recent years demands innovative strategies for the detection and combating of biofilms, which are notoriously resilient. Biofilms, particularly those on contact lenses, can lead to biofilm-related infections (e.g., conjunctivitis and keratitis), posing a significant risk to patients. Non-destructive and non-contact sensing techniques are essential in addressing this threat. Digital holographic tomography emerges as a promising solution. This allows for the 3D reconstruction of the refractive index distribution in biological samples, enabling label-free visualization and the quantitative analysis of biofilms. This tool provides insight into the dynamics of biofilm formation and maturation on the surface of transparent materials. Applying digital holographic tomography for biofilm examination has the potential to advance our ability to combat the antibiotic bacterial resistance crisis. A recent study focused on characterizing biofilm formation and maturation on six soft contact lens materials (three silicone hydrogels, three hydrogels), with a particular emphasis on Staphylococcus epidermis and Pseudomonas aeruginosa, both common culprits in ocular infections. The results revealed species- and time-dependent variations in the refractive indexes and volumes of biofilms, shedding light on cell dynamics, cell death, and contact lens material-related factors. The use of digital holographic tomography enables the quantitative analysis of biofilm dynamics, providing us with a better understanding and characterization of bacterial biofilms.

Inhibition of multiple staphylococcal growth states by a small molecule that disrupts membrane fluidity and voltage.

New molecular approaches to disrupting bacterial infections are needed. The bacterial cell membrane is an essential structure with diverse potential lipid and protein targets for antimicrobials. While rapid lysis of the bacterial cell membrane kills bacteria, lytic compounds are generally toxic to whole animals. In contrast, compounds that subtly damage the bacterial cell membrane could disable a microbe, facilitating pathogen clearance by the immune system with limited compound toxicity. A previously described small molecule, D66, terminates Salmonella enterica serotype Typhimurium (S. Typhimurium) infection of macrophages and reduces tissue colonization in mice. The compound dissipates bacterial inner membrane voltage without rapid cell lysis under broth conditions that permeabilize the outer membrane or disable efflux pumps. In standard media, the cell envelope protects Gram-negative bacteria from D66. We evaluated the activity of D66 in Gram-positive bacteria because their distinct envelope structure, specifically the absence of an outer membrane, could facilitate mechanism of action studies. We observed that D66 inhibited Gram-positive bacterial cell growth, rapidly increased Staphylococcus aureus membrane fluidity, and disrupted membrane voltage while barrier function remained intact. The compound also prevented planktonic staphylococcus from forming biofilms and a disturbed three-dimensional structure in 1-day-old biofilms. D66 furthermore reduced the survival of staphylococcal persister cells and of intracellular S. aureus. These data indicate that staphylococcal cells in multiple growth states germane to infection are susceptible to changes in lipid packing and membrane conductivity. Thus, agents that subtly damage bacterial cell membranes could have utility in preventing or treating disease.IMPORTANCEAn underutilized potential antibacterial target is the cell membrane, which supports or associates with approximately half of bacterial proteins and has a phospholipid makeup distinct from mammalian cell membranes. Previously, an experimental small molecule, D66, was shown to subtly damage Gram-negative bacterial cell membranes and to disrupt infection of mammalian cells. Here, we show that D66 increases the fluidity of Gram-positive bacterial cell membranes, dissipates membrane voltage, and inhibits the human pathogen Staphylococcus aureus in several infection-relevant growth states. Thus, compounds that cause membrane damage without lysing cells could be useful for mitigating infections caused by S. aureus.

New Library of Iodo-Quinoline Derivatives Obtained by an Alternative Synthetic Pathway and Their Antimicrobial Activity.

6-Iodo-substituted carboxy-quinolines were obtained using a one-pot, three-component method with trifluoroacetic acid as a catalyst under acidic conditions. Iodo-aniline, pyruvic acid and 22 phenyl-substituted aldehydes (we varied the type and number of radicals) or O-heterocycles, resulting in different electronic effects, were the starting components. This approach offers advantages such as rapid response times, cost-effective catalysts, high product yields and efficient purification procedures. A comprehensive investigation was conducted to examine the impact of aldehyde structure on the synthesis pathway. A library of compounds was obtained and characterized by FT-IR, MS, 1H NMR and 13C NMR spectroscopy and single-ray crystal diffractometry. Their antimicrobial activity against S. epidermidis, K. pneumonie and C. parapsilosis was tested in vitro. The effect of iodo-quinoline derivatives on microbial adhesion, the initial stage of microbial biofilm development, was also investigated. This study suggests that carboxy-quinoline derivatives bearing an iodine atom are interesting scaffolds for the development of novel antimicrobial agents.

Phenotypic and Genotypic Assays to Evaluate Coagulase-Negative Staphylococci Biofilm Production in Bloodstream Infections.

Coagulase-negative staphylococci (CoNS) are commensal on human body surfaces and, for years, they were not considered a cause of bloodstream infection and were often regarded as contamination. However, the involvement of CoNS in nosocomial infection is increasingly being recognized. The insertion of cannulas and intravascular catheters represents the primary source of CoNS entry into the bloodstream, causing bacteremia and sepsis. They owe their pathogenic role to their ability to produce biofilms on surfaces, such as medical devices. In this study, we evaluate the adhesive capacity of CoNS isolated from blood cultures by comparing a spectrophotometric phenotypic assay with genotypic analysis based on the evidence of the ica operon. We retrospectively reviewed the database of CoNS isolated from blood cultures from January to December 2021 that were considered responsible for 361 bloodstream infections. Eighty-nine CoNS were selected among these. Our data show that Staphylococcus epidermidis was the predominant species isolated, expressing greater adhesive capacities, especially those with the complete operon. Knowledge of the adhesive capabilities of a microorganism responsible for sepsis can be useful in implementing appropriate corrective and preventive measures, since conventional antibiotic therapy cannot effectively eradicate biofilms.

Biosynthesis of ZnO, Bi2O3 and ZnO-Bi2O3 bimetallic nanoparticles and their cytotoxic and antibacterial effects.

This work introduces an easy method for producing Bi2O3, ZnO, ZnO-Bi2O3 nanoparticles (NPs) by Biebersteinia Multifida extract. Our products have been characterized through the outcomes which recorded with using powder X-ray diffractometry (PXRD), Raman, energy dispersive X-ray (EDX), field emission-scanning electron microscopy (FE-SEM), and Fourier-transform infrared (FT-IR) techniques. The finding of SEM presented porous structure and spherical morphology for Bi2O3 and ZnO NPs, respectively. While FE-SEM image of bimetallic nanoparticles showed both porous and spherical morphologies for them; so that spherical particles of ZnO have sat on the porous structure of Bi2O3 NPs. According to the PXRD results, the crystallite sizes of Bi2O3, ZnO and ZnO-Bi2O3 NPs have been obtained 57.69, 21.93, and 43.42 nm, respectively. Antibacterial performance of NPs has been studied on Staphylococcus epidermidis and Pseudomonas aeruginosa bacteria, to distinguish the minimum microbial inhibitory concentration (MIC). Antimicrobial outcomes have showed a better effect for ZnO-Bi2O3 NPs. Besides, wondering about the cytotoxic action against cancer cell lines, the MTT results have verified the intense cytotoxic function versus breast cancer cells (MCF-7). According to these observations, obtained products can prosper medical and biological applications.

In Vitro Assessment of Bacterial Adhesion and Biofilm Formation on Novel Bioactive, Biodegradable Electrospun Fiber Meshes Intended to Support Tendon Rupture Repair.

The surgical repair of a ruptured tendon faces two major problems: specifically increased fibrous adhesion to the surrounding tissue and inferior mechanical properties of the scar tissue compared to the native tissue. Bacterial attachment to implant materials is an additional problem as it might lead to severe infections and impaired recovery. To counteract adhesion formation, two novel implant materials were fabricated by electrospinning, namely, a random fiber mesh containing hyaluronic acid (HA) and poly(ethylene oxide) (PEO) in a ratio of 1:1 (HA/PEO 1:1) and 1:4 (HA/PEO 1:4), respectively. Electrospun DegraPol (DP) treated with silver nanoparticles (DP-Ag) was developed to counteract the bacterial attachment. The three novel materials were compared to the previously described DP and DP with incorporated insulin-like growth factor-1 (DP-IGF-1), two implant materials that were also designed to improve tendon repair. To test whether the materials are prone to bacterial adhesion and biofilm formation, we assessed 10 strains of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Enterococcus faecalis, known for causing nosocomial infections. Fiber diameter, pore size, and water contact angle, reflecting different degrees of hydrophobicity, were used to characterize all materials. Generally, we observed higher biofilm formation on the more hydrophobic DP as compared to the more hydrophilic DP-IGF-1 and a trend toward reduced biofilm formation for DP treated with silver nanoparticles. For the two HA/PEO implants, a similar biofilm formation was observed. All tested materials were highly prone to bacterial adherence and biofilm formation, pointing toward the need of further material development, including the optimized incorporation of antibacterial agents such as silver nanoparticles or antibiotics.

Antibiotic adjuvant activities of quorum sensing signal molecules DSF and BDSF against mature biofilms of Staphylococci.

Among promising antibiofilm compounds, quorum-sensing (QS) molecules that regulate biological processes such as biofilm formation and intra- or interspecies communication appear to be good candidates. The invitro antibiotic-adjuvant effects of QS molecules diffusible signal factor (DSF) and B. cenocepacia producing-DSF (BDSF) were investigated against mature Staphylococcal biofilms. Broth microdilution methods were used for the determinations of MIC, MBC, MBIC, and MBEC, and bactericidal activities were determined by TKC method. The lowest MICs were obtained with ciprofloxacin and gentamicin, and MBECs with ciprofloxacin. DSF and BDSF at 0.5 µM decreased the MICs as 2-8, and 2-32 fold, respectively. In TKC studies, -cidal activities were achieved by BDSF + gentamycin, or ciprofloxacin, and DSF + daptomycin, vancomycin, meropenem or gentamycin combinations. Synergistic effects were generally obtained with BDSF + gentamicin combinations, followed by DSF + daptomycin against most S. aureus; while BDSF + gentamicin or ciprofloxacin, and DSF + vancomycin or meropenem were synergist against some S. epidermidis biofilms. Also, the antagonist effects were observed with BDSF + meropenem or ciprofloxacin against each MSSE and MSSA. It is estimated that these QS molecules, although it was strain dependent, generally enhanced the antibiotic activity, and would be a new and effective treatment strategy for biofilm control, either alone or as an antibiotic adjuvant.

Citrobacter koseri inhibits the growth of Staphylococcus epidermidis by suppressing iron utilization.

The human skin microbiome consists of many species of bacteria, including Staphylococcus aureus and S. epidermidis. Individuals with atopic dermatitis (AD) have an increased relative abundance of S. aureus, which exacerbates the inflammation of AD. Although S. epidermidis, a main component of healthy skin microbiota, inhibits the growth of S. aureus, the balance between S. epidermidis and S. aureus is disrupted in the skin of individuals with AD. In this study, we found that Citrobacter koseri isolated from patients with AD produces substances that inhibit the growth of S. epidermidis. Heat-treated culture supernatant (CS) of C. koseri inhibited the growth of S. epidermidis but not S. aureus. The genome of C. koseri has gene clusters related to siderophores and the heat-treated CS of C. koseri contained a high concentration of siderophores compared with the control medium. The inhibitory activity of C. koseri CS against the growth of S. epidermidis was decreased by the addition of iron, but not copper or zinc. Deferoxamine, an iron-chelating agent, also inhibited the growth of S. epidermidis, but not that of S. aureus. These findings suggest that C. koseri inhibits the growth of S. epidermidis by interfering with its iron utilization.

mecA and fdh: markers of pathogenicity and commensalism in Staphylococcus epidermidis of pediatric origin from Pakistan.

Staphylococcus epidermidis is an opportunistic bacterial pathogen. The study screened isolates of S. epidermidis of pediatric origin for genetic markers of discriminatory potential. 103 isolates (n = 75 clinical; n = 28 community) were screened for methicillin resistance (mecA), formate dehydrogenase (fdh) and an array of virulence factors through multiplex PCR and Congo red assay. The isolates were typed in four distinct categories, based on the presence of selected virulent factors. The type A clinical isolates carrying icaADBC operon (n = 22; 29.3%, P = 0.117) were not significantly differentiating the origin of isolates. The type B clinical isolates representing methicillin resistant S. epidermidis (MRSE) (n = 73; 97.3%, P < 0.00001) and the type C clinical isolates lacking formate dehydrogenase fdh (n = 62; 82.6%, P < 0.00001) were having significant discriminatory potential of clinical isolates, respectively. All type D community isolates were carrying fdh (n = 28; 100%, P < 0.00001). MecA and fdh are significant differential markers of pathogenicity and commensalism in S. epidermidis of pediatric origin.

Antiseptics and mupirocin resistance in clinical, environmental, and colonizing coagulase negative Staphylococcus isolates.

BACKGROUND: Coagulase-Negative Staphylococci (CoNS) are opportunistic and nosocomial pathogens. The excessive use of antimicrobial agents, including antiseptics, represents one of the world's major public health problems. This study aimed to test the susceptibility of CoNS to antiseptics. METHODS: Out of 250 specimens collected from different sections of the hospital, 55 samples were identified as CoNS, categorized into three groups based on their sources: environmental samples (n = 32), healthcare worker carriers samples (n = 14), and clinical infection samples (n = 9). Isolates were examined for susceptibility to antibiotics and antiseptics, such as benzalkonium chloride (BC), cetyltrimethylammonium bromide (CTAB), and chlorhexidine digluconate (CHDG). Mupirocin and antiseptic resistance genes, as well as the mecA gene, were detected using polymerase chain reaction. CoNS isolates with notable resistance to antiseptics and antibiotics were identified using the API-Staph system. RESULTS: A high frequency of multidrug resistance among CoNS clinical infection isolates was observed. Approximately half of the CoNS isolates from healthcare workers were susceptible to CHDG, but 93% were resistant to BC and CTAB. The frequency of antiseptics and antibiotics resistance genes in CoNS isolates was as follows: qacA/B (51/55; 92.7%), smr (22/55; 40.0%), qacG (1/55; 1.8%), qacH (6/55; 10.9%), qacJ (4/55; 7.3%), mecA (35/55; 63.6%), mupB (10/55; 18.2%), and mupA (7/55; 12.7%). A significant difference in the prevalence of smr gene and qacJ genes between CoNS isolates from healthcare workers and other isolates was reported (P value = 0.032 and ˂0.001, respectively). Four different CoNS species; S. epidermidis, S. chromogene, S. haemolyticus, and S. hominis, were identified by API. CONCLUSIONS: CoNS isolates colonizing healthcare workers showed a high prevalence of antiseptic resistance genes, while clinical infection samples were more resistant to antibiotics. CHDG demonstrated greater efficacy than BC and CTAB in our hospital.

Tuning of Silver Content on the Antibacterial and Biological Properties of Poly(ɛ-caprolactone)/Biphasic Calcium Phosphate 3D-Scaffolds for Bone Tissue Engineering.

There is a growing interest in tissue engineering, in which biomaterials play a pivotal role in promoting bone regeneration. Furthermore, smart functionalization can provide biomaterials with the additional role of preventing orthopedic infections. Due to the growing microbial resistance to antimicrobials used to treat those infections, metal ions, such as silver, thanks to their known wide range of bactericidal properties, are believed to be promising additives in developing antibacterial biomaterials. In this work, novel poly(ε-caprolactone) (PCL)-based 3D scaffolds have been designed and developed, where the polymer matrix was modified with both silver (Ag), to supply antibacterial behavior, and calcium phosphates (biphasic calcium phosphate, BCP) particles to impart bioactive/bioresorbable properties. The microstructural analysis showed that constructs were characterized by square-shaped macropores, in line with the morphology and size of the templating salts used as pore formers. Degradation tests demonstrated the important role of calcium phosphates in improving PCL hydrophilicity, leading to a higher degradation degree for BCP/PCL composites compared to the neat polymer after 18 days of soaking. The appearance of an inhibition halo around the silver-functionalized PCL scaffolds for assayed microorganisms and a significant (p < 0.05) decrease in both adherent and planktonic bacteria demonstrate the Ag+ release from the 3D constructs. Furthermore, the PCL scaffolds enriched with the lowest silver percentages did not hamper the viability and proliferation of Saos-2 cells. A synergic combination of antimicrobial, osteoproliferative and biodegradable features provided to 3D scaffolds the required potential for bone tissue engineering, beside anti-microbial properties for reduction in prosthetic joints infections.

Influence of Staphylococcus epidermidis on Collagen Crimp Patterns of Soft Tissue Allograft.

BACKGROUND: Postoperative infections, commonly from Staphylococcus epidermidis, may result in anterior cruciate ligament graft failure and necessitate revision surgery. In biomechanical studies, S. epidermidis has been shown to establish biofilms on tendons and reduce graft strength. PURPOSE/HYPOTHESIS: The goal of this study was to determine the effect of bacterial bioburden on the collagen structure of tendon. It was hypothesized that an increase in S. epidermidis biofilm would compromise tendon crimp, a pattern necessary for mechanical integrity, of soft tissue allografts. STUDY DESIGN: Controlled laboratory study. METHODS: Cultures of S. epidermidis were used to inoculate tibialis anterior cadaveric tendons. Conditions assessed included 5 × 105 colony-forming units or concentrated spent media from culture (no living bacteria). Incubation times of 30 minutes, 3 hours, 6 hours, and 24 hours were utilized. Second-harmonic generation imaging allowed for visualization of collagen autofluorescence. Crimp lengths were determined using ImageJ and compared based on incubation time. RESULTS: Incubation time positively correlated with increasing S. epidermidis bioburden. Both fine and coarse crimp patterns lengthened with increasing incubation time. Significant coarse crimp changes were observed after only 30-minute incubations (P < .029), whereas significant fine crimp lengthening occurred after 6 hours (P < .0001). No changes in crimp length were identified after incubation in media lacking living bacteria. CONCLUSION: The results of this study demonstrate that exposure to S. epidermidis negatively affects collagen crimp structure. Structural alterations at the collagen fiber level occur within 30 minutes of exposure to media containing S. epidermidis. CLINICAL RELEVANCE: Our study highlights the need for antimicrobial precautions to prevent graft colonization and maximize graft mechanical strength.

Staphylococcus epidermidis isolates from atopic or healthy skin have opposite effect on skin cells: potential implication of the AHR pathway modulation.

Introduction: Staphylococcus epidermidis is a commensal bacterium ubiquitously present on human skin. This species is considered as a key member of the healthy skin microbiota, involved in the defense against pathogens, modulating the immune system, and involved in wound repair. Simultaneously, S. epidermidis is the second cause of nosocomial infections and an overgrowth of S. epidermidis has been described in skin disorders such as atopic dermatitis. Diverse isolates of S. epidermidis co-exist on the skin. Elucidating the genetic and phenotypic specificities of these species in skin health and disease is key to better understand their role in various skin conditions. Additionally, the exact mechanisms by which commensals interact with host cells is partially understood. We hypothesized that S. epidermidis isolates identified from different skin origins could play distinct roles on skin differentiation and that these effects could be mediated by the aryl hydrocarbon receptor (AhR) pathway. Methods: For this purpose, a library of 12 strains originated from healthy skin (non-hyperseborrheic (NH) and hyperseborrheic (H) skin types) and disease skin (atopic (AD) skin type) was characterized at the genomic and phenotypic levels. Results and discussion: Here we showed that strains from atopic lesional skin alter the epidermis structure of a 3D reconstructed skin model whereas strains from NH healthy skin do not. All strains from NH healthy skin induced AhR/OVOL1 path and produced high quantities of indole metabolites in co-culture with NHEK; especially indole-3-aldehyde (IAld) and indole-3-lactic acid (ILA); while AD strains did not induce AhR/OVOL1 path but its inhibitor STAT6 and produced the lowest levels of indoles as compared to the other strains. As a consequence, strains from AD skin altered the differentiation markers FLG and DSG1. The results presented here, on a library of 12 strains, showed that S. epidermidis originated from NH healthy skin and atopic skin have opposite effects on the epidermal cohesion and structure and that these differences could be linked to their capacity to produce metabolites, which in turn could activate AHR pathway. Our results on a specific library of strains provide new insights into how S. epidermidis may interact with the skin to promote health or disease.

Photoactivatable Heptamethine-Based Carbonic Anhydrase Inhibitors Leading to New Anti-Antibacterial Agents.

With the aim to propose innovative antimicrobial agents able to not only selectively inhibit bacterial carbonic anhydrases (CAs) but also to be photoactivated by specific wavelengths, new heptamethine-based compounds decorated with a sulfonamide moiety were synthesized by means of different spacers. The compounds displayed potent CA inhibition and a slight preference for bacterial isoforms. Furthermore, minimal inhibitory and bactericidal concentrations and the cytotoxicity of the compounds were assessed, thus highlighting a promising effect under irradiation against S. epidermidis. The hemolysis activity test showed that these derivatives were not cytotoxic to human red blood cells, further corroborating their favorable selectivity index. This approach led to the discovery of a valuable scaffold for further investigations.