Cutibacterium acnes as an Opportunistic Pathogen: An Update of Its Virulence-Associated Factors

The binding modes of brazilin and hematein from Caesalpinia sappan L. to Cutibacterium acnes lipase: Simulation studies

The growing concern over antimicrobial resistance in Cutibacterium acnes (C. acnes) has spurred interest in alternative acne treatments, particularly herbal medicines. This study evaluates the binding affinities of established anti-acne agents-ketoconazole (KET) and tetracycline (TET)-alongside natural compounds, brazilin (BRA) and hematein (HEM), derived from Caesalpinia sappan L. (C. sappan), to C. acnes lipase. Through molecular docking and dynamics simulations, we demonstrate that the asymmetric lipase dimer operates independently. Bulky compounds such as KET and TET inhibit lipase activity via π-π interactions, primarily targeting the lid domain. In contrast, smaller ligands BRA and HEM exhibit unique binding modes: BRA mirrors TET by localizing near the lid domain, while HEM shows dual interactions with both the lid and catalytic sites. These results underscore the potential of BRA and HEM as promising anti-acne agents, indicating that C. sappan could be an effective herbal remedy for acne. This study provides a foundation for further exploration of natural products in combating acne and mitigating antimicrobial resistance.

Scalable propionic acid production using Cutibacterium acnes ZW-1: Insights into substrate and pH-driven carbon flux

An acid-resistant Cutibacterium acnes ZW-1 was isolated from human skin, and propionic acid (PA) production under different substrate and pH conditions was studied. When the molar ratio of lactic acid (LA) to acetic acid (AA) was 7:1 and the pH was 6.5, the PA concentration could reach 64.84 mM. Meanwhile, the index analysis and enzyme activity revealed that the PA carbon flux was 59 %, the PA electronic efficiency reached 79 %, and the propionyl-CoA carboxylase activity was 1.075 mmol·mg protein-1. Considering the competition between AA/PA production and biomass synthesis, although the slightly acidic pH (<6.5) would promote the flow of carbon to PA, its concentration was severely inhibited due to the limitation of biomass. Further scale-up verification in an automated bioreactor indicated that PA production improved, up to 83.31 mM, and the production rate reached 1.066 g·L-1·d-1. This work may provide support for the industrial application of PA bioproduction.

Whole-genome sequencing analysis of Cutibacterium spp. recovered from health care-associated endodontic infections

OBJECTIVE

Cutibacterium acnes (C. acnes) has been detected in culture and molecular studies of endodontic microbiota, indicating its potential as a neglected pathogen in endodontic infections. This study aimed to conduct a complete genomic analysis of three Cutibacterium spp. isolates obtained from persistent endodontic infections in patients from Chile.

DESIGN

Whole genome sequencing and comprehensive genomic analysis using diverse bioinformatics platforms and databases were carried out.

RESULTS

In-silico analysis confirmed that strains A1 and E3 correspond to C. acnes species, while strain B1 corresponds to C. namnetense. Additionally, C. acnes strain A1 belongs to the phylotype IA1, sequence type (ST) 4 and belongs to the clonal complex (CC) 4, whereas C. acnes strain E3 belongs to a novel ST. No antibiotic resistance, however, a variable distribution and identity of the VF was found.

CONCLUSIONS

Detailed analysis of genes associated with virulence factors shed light on the intrinsic pathogenic capacity of these strains, which may indicate differential adaptation to their specific niches or diversity in pathogenicity within the species.

Comparative efficacy of essential oils against Cutibacterium acnes: Effect upon strains from phylotypes with different virulence patterns

OBJECTIVES

Despite being a commensal of human skin, Cutibacterium acnes plays an important role in the pathogenesis of Acne vulgaris, with the loss of bacterial phylotype diversity being related to disease progression. This study evaluated differences in the virulence profile of C. acnes strains from different phylotypes and investigated the possible phylotype-selective efficacy of essential oils (EOs) from Thymus x citriodorus (TC), Thymus mastichina, and Cistus ladanifer compared to Melaleuca alternifolia (tea tree), focusing on both planktonic and biofilm growth forms, the latter being related with pathogenesis and treatment resistance.

METHODS

One collection strain and seven clinical isolates were classified into phylotypes using multiplex-touchdown PCR. Virulence trait differences across phylotypes were evaluated by studying antibiotic resistance, biofilm formation, porphyrin production, and lipase activity. EOs were tested for minimum inhibitory/bactericidal concentrations (MIC/MBC) and effects on biofilm biomass and metabolic activity.

RESULTS

Strains from phylotype IA1 were higher biofilm and lipase producers than phylotype II strains. Regarding EO's efficacy, TC EO presented lower planktonic MIC values for all strains compared to the other EOs, presenting a smaller difference in MIC values across phylotypes. TC EO was able to similarly reduce biofilm biomass and metabolic activity in phylotype IA1 clinical strains, being effective at lower concentrations compared with the remaining EOs.

CONCLUSIONS

Not all virulence traits were phylotype-related, highlighting the multifactorial nature of the disease. TC EO showed a relevant anti-acne potential, outperforming tea tree EO (a species with a commercial claim for Acne vulgaris) against both planktonic and biofilm growth forms of C. acnes.

Novel-designed antimicrobial peptides with dual antimicrobial and anti-inflammatory actions against Cutibacterium acnes for acne vulgaris therapy

Acne vulgaris is a prevalent skin condition among adolescents, primarily instigated by over-colonization and subsequent inflammation triggered by Cutibacterium acnes. Although topical and oral antibiotics are standard treatments, they often lead to the proliferation of antibiotic-resistant bacteria and are associated with undesirable side effects. Antimicrobial peptides (AMPs) are considered a promising solution to these challenges. In this study, we aimed to develop novel short AMPs to combat C. acnes. By comparing sequences and abstracting the distribution of residue types of established AMPs, we derived a sequence template. Using this template, we crafted novel anti-C. acnes peptides comprising 13 amino acid residues. To enhance their potential therapeutic application, we designed a series of peptides by varying the number and position of the tryptophan residues. Among these peptides, DAP-7 and DAP-10 demonstrated potent antimicrobial activity against both antibiotic-susceptible and -resistant strains of C. acnes, with minimal cytotoxicity. The antimicrobial action of these peptides was attributed to their ability to target the bacterial membrane, resulting in permeabilization and rupture. Moreover, DAP-7 and DAP-10 effectively reduced the expression of pro-inflammatory cytokines induced by C. acnes and remained stable for up to 12 h after exposure to proteases found in acne lesions. Notably, DAP-7 decreased the C. acnes colonies on the ears and significantly alleviated C. acnes-induced ear swelling in a mouse model. Our findings suggest that the DAP-7 and DAP-10 peptides hold promise as candidates for developing a new acne vulgaris treatment.

Functional characterization of Staphylococcus aureus lipase 2 (SAL2) as a collagen adhesin

Extracellular lipases of many pathogens have been characterized as human virulence factors. Staphylococcus aureus produces a variety of enzymes that aid in the pathogenesis of the bacterium to invade and destroy host tissues, resulting in a wide range of clinical illnesses. The lipase is one such enzyme, and the lipases produced by S. aureus (SAL1, SAL2 and SAL3) have been associated with the virulence of the bacterium. In the present study, we cloned, expressed and purified the mature lipase domain of SAL2 (rSAL2296-690) and characterized its interaction with human collagen type IV using biolayer interferometry (BLI), molecular docking and simulation studies. Collagen binds to rSAL2296-690 with an affinity of 3.261 μM. The enzymatic activity of rSAL2296-690 was analyzed in the presence of collagen and orlistat, a potent lipase inhibitor. The activity of rSAL2296-690 in the presence of collagen or orlistat was nearly 90 fold lower than that of the native rSAL2296-690. The optimal pH and temperature for rSAL2296-690 activity were found at 7 and 25 °C respectively. rSAL2296-690 found to be stable at pH 7 and exhibits thermostability in the temperature range 15-25 °C. With CaCl2 and ZnCl2, an increase in activity of rSAL2296-690 was observed whereas NiSO4, CuSO4, MnCl2, CoCl2 and MgCl2 reduced the activity. No substrate specificity was found with rSAL2296-690, as it cleaves different substrate lengths (C2, C6, C12 and C16) and triglyceride triolein. Interaction of rSAL2296-690 with metal-incubated collagen revealed that the binding affinity of collagen in the presence of NiSO4, CuSO4 and CoCl2 significantly reduced. Enzymatic and collagen binding studies provided insights into the putative collagen binding site on SAL2296-690, which is near the active site region of the molecule. This study thus revealed that rSAL2296-690 as a bi-functional molecule, acts not only as a lipase but also as a collagen adhesin.

Cytokine responses of CD4+ T cells and NKT cells to periodontitis-associated bacteria in individuals with or without periodontitis

AIM

Periodontitis is an inflammatory disease driven by opportunistic bacteria including Porphyromonas gingivalis and Fusobacterium nucleatum, where T-cell and NKT-cell responses to these bacteria in patients with periodontitis grade B or C are not fully elucidated. The objective is to determine if exaggerated proinflammatory Th-cell responses to periodontitis-associated bacteria, but not commensal bacteria, is a characteristic of increased periodontitis grade.

METHODS

Mononuclear cells from patients with periodontitis grade C (n = 26) or grade B (n = 33) and healthy controls (HCs; n = 26) were stimulated with P. gingivalis, F. nucleatum or the commensal bacteria, Staphylococcus epidermidis and Cutibacterium acnes. Cytokine production by different T-cell populations and FOXP3-expression by regulatory T cells were assessed by flow cytometry.

RESULTS

Compared to HCs, grade C patients had decreased frequencies of interleukin (IL)-10-producing CD4+ T cells before stimulation (p = .02) and increased frequencies of IFN-y-producing CD4+ T cells after stimulation with P. gingivalis (p = .0019). Grade B patients had decreased frequencies of FOXP3+ CD4+ T cells before (p = .030) before and after stimulation with anti-CD2/anti-CD3/anti-CD28-loaded beads (p = .047), P. gingivalis (p = .013) and S. epidermidis (p = .018). Clinical attachment loss correlated with the frequencies of IFN-y-producing Th1 cells in P. gingivalis- and F. nucleatum-stimulated cultures in grade B patients (p = .023 and p = .048, respectively) and with the frequencies of Th17 cells in P. gingivalis-stimulated cultures (p = .0062) in grade C patients. Patients with periodontitis grade C or grade B showed lower frequencies of IL-10-producing NKT cells than HCs in unstimulated cultures (p = .0043 and p = .027 respectively).

CONCLUSIONS

Both periodontitis groups showed decreased frequencies of immunoregulatory T-cell and NKT cell subsets at baseline. Clinical attachment loss correlated with P. gingivalis-induced Th17-responses in grade C patients and with Th1-responses in grade B patients when cells were stimulated with P. gingivalis, supporting that dysregulated pro-inflammatory T-cell responses to periodontitis-associated bacteria contribute to the pathogenesis of periodontitis.

Antibacterial activity and impact on keratinocyte cell growth of Cutibacterium acnes bacteriophages in a Cutibacterium acnes IA1- colonized keratinocyte model

Acne is an inflammatory disease in which microbial disbalance is represented by an augmented population of phylotype IA1 of Cutibacterium acnes. Various treatments for acne can cause side effects, and it has been reported that C. acnes is resistant to prescribed antibiotics. Phage therapy has been proposed as an alternative treatment for acne, given its species-specificity to kill bacteria, its relative innocuity, and its potential to manage antibiotic-resistant pathogens. Moreover, bacteriophages (phages) may modulate the microbiota and immune responses. Some studies have shown the potential use of phages in the treatment of acne. Nevertheless, the capacity to specifically reduce phylotype IA1 and the effect of phage treatment on skin cells are poorly understood. We assessed the capacity of phages to clear C. acnes IA1 and their effects on cell cytotoxicity and growth in HEKa cells- C. acnes IA1 co-culture. Phylotypes IA1 and IB had similar effects on HEKa cells, causing cytotoxicity and diminishing cell growth. Nevertheless, IA1 caused a higher impact on cell doubling time by increasing it 1.8 times more than cell growth control group. Even though there are no phages IA1-specific, we found phages that have a diminished effect on other phylotypes not related to acne. Phage treatment in general reduced IA1-caused cytotoxicity, with differences in efficacy among phages. In addition, phage purification was necessary to restore metabolic activity and growth of HEKa. Overall, phage evaluation as a therapeutic alternative should include phage-bacteria interactions and their impact on skin cells because of the differences that each phage can exhibit.

Distinct Intraspecies Variation of Cutibacterium acnes and Staphylococcus epidermidis in Acne Vulgaris and Healthy Skin

Human skin hosts a diverse array of microorganisms that contribute to its health. Key players in the facial skin microbiome include Cutibacterium acnes and staphylococci, whose colonization patterns may influence dermatological conditions like acne vulgaris. This study examined the facial microbiome composition of 29 individuals, including 14 with moderate to severe acne and 15 with healthy skin, using single locus sequence typing (SLST) amplicon sequencing. The results showed a shift in the relative abundances of C. acnes phylotypes: SLST types A, C, and F were increased in acne, while types H, K, and L were reduced compared to healthy skin. Among staphylococci, the relative abundance of S. epidermidis, S. capitis, and S. saphrophyticus increased in acne, while S. saccharolyticus and S. hominis decreased. The amplicon sequencing approach could also identify a population shift of S. epidermidis: a specific S. epidermidis phylogenetic lineage (type 3) was reduced in acne, while two abundant lineages (types 1 and 2) were elevated. These findings suggest that distinct phylogenetic lineages of both C. acnes and S. epidermidis are linked to healthy versus diseased skin, highlighting a potential role for both microorganisms in disease prevention and aggravation, respectively.

Diagnostic and therapeutic strategies in combating implanted medical device-associated bacterial biofilm infections

Bacterial biofilms exhibit remarkable resistance against conventional antibiotics and are capable of evading the humoral immune response. They account for nearly 80% of chronic infections in humans. Development of bacterial biofilms on medical implants results in their malfunctioning and subsequently leads to high mortality rates worldwide. Therefore, early and precise diagnosis of bacterial biofilms on implanted medical devices is essential to prevent their failure and associated complications. Culture-based methods are time consuming, more prone to contamination and often exhibit low sensitivity. Different molecular, imaging, and physical methods can aid in more accurate and faster detection of implant-associated bacterial biofilms. Biofilm growth on implant surface can be prevented either through modification of the implant material or by application of different antibacterial coatings on implant surface. Experimental studies have shown that pre-existing biofilms from medical implants can be removed by breaking down biofilm matrix, utilizing physical methods, nanomaterials and antimicrobial peptides. The current review delves into mechanism of biofilm formation on implanted medical devices and the subsequent host immune response. Much emphasis has been laid on different ongoing diagnostic and therapeutic strategies to achieve improved patient outcomes and reduced socio-economic burden.

Vaccines in Dermatology-Present and Future: A Review

Dermatological vaccines have emerged as critical tools in preventing and managing a wide spectrum of skin conditions ranging from infectious diseases to malignancies. By synthesizing evidence from existing literature, this review aims to comprehensively evaluate the efficacy, safety, and immunogenicity of vaccines used in dermatology, including both approved vaccines and those currently being researched. Vaccines discussed in this paper include those targeting dermatoses and malignancies (e.g., acne vulgaris, atopic dermatitis, and melanoma); infectious diseases (e.g., human papillomavirus (HPV); varicella zoster virus (VZV); herpes zoster (HZ); warts; smallpox; mpox (monkeypox); hand, foot, and mouth disease (HFMD); candidiasis and Group B Streptococcus (GBS); and neglected tropical diseases (e.g., Buruli ulcer, leprosy, and leishmaniasis). Through this review, we aim to provide a detailed understanding of the role of vaccines in dermatology, identify knowledge gaps, and propose areas for future research.

Marine actinobacteria metabolites: unlocking new treatments for acne vulgaris

Marine-derived actinobacteria isolated from sponge Cliona varians and soft coral Eunicea fusca were screened for antibacterial activity against acne-related bacteria, specifically Staphylococcus epidermidis ATCC 14990, methicillin-resistant Staphylococcus aureus ATCC BAA44, and Cutibacterium acnes ATCC 6919. Cytotoxicity assays were performed on human dermal fibroblast (HDFa) and keratinocyte (HaCaT) cell lines to assess the safety profile of the extracts. Chemical characterization was conducted using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Among the extracts, six derived from Kocuria sp., Rhodococcus sp., Nocardia sp., Micrococcus sp., and Streptomyces sp. demonstrated significant antibacterial activity. Notably, extract Z9.216 from Kocuria sp. exhibited the highest efficacy, inhibiting S. epidermidis by 68%, S. aureus by 93%, and C. acnes by 98.7% at a concentration of 0.003 mg/mL, which was comparable to the standard antibiotics erythromycin and vancomycin, while maintaining over 90% cell viability in both HDFa and HaCaT cell lines. Untargeted metabolomic analysis suggested that antibacterial activity might be associated with compounds from the chemical families of alkaloids, terpenoids, and fatty acids, among others. These findings highlight the therapeutic potential of marine actinobacteria in underexplored environments as a promising strategy for treating acne vulgaris, a chronic inflammatory skin condition.

Cutibacterium acnes and its complex host interaction in prosthetic joint infection: Current insights and future directions

Cutibacterium acnes is a commensal Gram-positive anaerobic bacterium that can also act as an opportunistic pathogen in various diseases, particularly in prosthetic joint infections (PJI). Throughout this review, we delve into the current understanding of the intricate interactions between C. acnes and host cells and discuss bacterial persistence in the host. C. acnes colonization and subsequent PJI set-up represent complex processes involving bacterial adhesion, immune recognition, and host response mechanisms. We highlight existing knowledge and gaps in specific host-pathogen interactions and stress the importance of acquiring additional information to develop targeted strategies for preventing and treating C. acnes-related PIJ.

Exploring the Biological Activity of Phytocannabinoid Formulations for Skin Health Care: A Special Focus on Molecular Pathways

Recent advancements have highlighted the potential of cannabis and its phytocannabinoids (pCBs) in skin health applications. These compounds, through their interaction with the endocannabinoid system (ECS), show promise for skin health products. Their ability to regulate inflammation, oxidative stress and cell proliferation makes them useful in addressing skin problems such as inflammation, scarring, healing, acne and aging, positioning them as valuable tools for innovative skincare solutions. In the present work, the cellular and molecular effects of proprietary pCB-based formulations on ECS modulation, inflammation and skin regeneration were investigated. Using human dermal fibroblasts (HDF) and keratinocytes (HaCaT), the effect of formulations in both pre-treatment and treatment scenarios following exposure to stress-inducing agents was assessed. Key molecular markers were analyzed to tackle their efficacy in mitigating inflammation and promoting structural integrity and regeneration. In vitro results showed that these formulations significantly reduced inflammation, promoted skin regeneration and improved structural functions. In vivo studies confirmed that the formulations were well-tolerated and led to noticeable improvements in skin health, including enhanced barrier function. This study demonstrates the safety and efficacy of pCB-based formulations for cosmeceutical applications. By combining molecular analysis with in vivo testing, this research provides new insights into the therapeutic potential of pCBs for managing various skin conditions.

A review of bacterial and osteoclast differentiation in bone infection

Bone infections are characterized by bacterial invasion of the bone microenvironment and subsequent bone structure deterioration. This holds significance because osteoclasts, which are the only cells responsible for bone resorption, are abnormally stimulated during bone infections. Multiple communication factors secreted by bone stromal cells regulate the membrane of osteoclast progenitor cells, thereby maintaining bone homeostasis through the expression of many types of receptors. During infection, the immunoinflammatory response triggered by bacterial invasion and multiple virulence factors of bacterial origin can disrupt osteoclast homeostasis. Therefore, clarifying the pathways through which bacteria affect osteoclasts can offer a theoretical basis for preventing and treating bone infections. This review summarizes studies investigating bone destruction caused by different bacterial infections. In conclusion, bacteria can affect osteoclast metabolic activity through multiple pathways, including direct contact, release of virulence factors, induction of immunoinflammatory responses, influence on bone stromal cell metabolism, and intracellular infections.

The Influence of the Amphiphilic Properties of Peptides on the Phosphatidylinositol Monolayer in the Presence of Ascorbic Acid

Acne vulgaris is one of the most common dermatological diseases and is strongly connected with the pathological growth of the Cutibacterium acnes. More than half of the cultures of this bacterium are resistant to antibiotics, resulting in the proposal of the use of antibacterial peptides as an alternative to traditional antibiotics. Ascorbic acid (AA) and its antioxidant properties may ally in acne therapy. The aim of this study was to determine the influence of the selected antibacterial peptides in the presence of ascorbic acid and 3-O-ethyl-ascorbic acid (EAA) on the properties of the monolayer formed by phosphatidylinositol. Studies of the properties of the phosphatidylinositol monolayer were carried out using the Langmuir-Wilhelmy balance. The recorded compression isotherms, hysteresis loops, and surface pressure values recorded at specific time intervals were evaluated to assess the influence of ascorbic acid and its derivatives in the presence of antimicrobial peptides on the stability and organization of phosphatidylinositol monolayers. The addition of AA to the subphase caused a faster phase transition at over 60 Å2/molecule and significantly reduced the plateau surface pressure by about 20% in most of the systems tested. The studied monolayers were found to be in the expanded liquid state (40.23-49.95 [mN/m]) or in the transition between the expanded and condensed liquid phase (51.47-60.98 [mN/m]). Compression and decompression isotherms indicated the highest flexibility of the systems at 20 °C and 25 °C. The surface pressure versus time dependence indicated the stability of the phosphatidylinositol monolayer with 3-O-ethyl-ascorbic acid and antimicrobial peptides up to 35 °C.

The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes

Keratinocytes can be activated by Cutibacterium acnes, leading to the production of proinflammatory cytokines via toll-like receptors (TLRs) 2 and 4. Although several studies have investigated keratinocytes, the mechanism of calcium-mediated activation remains unclear. Herein, we investigated whether calcium influx via TLR2 and TLR4 stimulation was involved in cytokine secretion by keratinocytes in HaCaT cells. Although TLR2 stimulation by peptidoglycan (PGN) increased intracellular calcium influx, TLR4 stimulation by lipopolysaccharide (LPS) did not increase it, as analyzed using flow cytometry with the calcium indicator Fluo-3. However, activation by either TLR2 or TLR4 ligands upregulated the intracellular calcium influx in THP-1 monocytes. Additionally, the expression of major proinflammatory cytokines and chemokines, such as interleukin (IL)-6, IL-8, IL-1α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein-1 (MCP-1), was significantly increased by TLR2 in HaCaT cells. Moreover, treatment with the intracellular calcium chelator, BAPTA-AM, disrupted PGN-mediated induction of IL-6, IL-8, and MCP-1 production. Real-time quantitative polymerase chain reaction (PCR) and western blotting revealed that TLR2 stimulation induced expression of the epidermal differentiation marker keratin 1. In conclusion, TLR2-induced intracellular calcium influx plays a pivotal role in the secretion of proinflammatory cytokines, such as IL-6 and MCP-1, in keratinocytes. Moreover, the continuous influx of calcium via TLR2 activation leads to keratinization. In vitro studies using HaCaT cells provide basic research on the effect of TLR2-induced calcium on C. acnes-mediated inflammation in keratinocytes. These studies are limited in their ability to clinically predict what happens in human keratinocytes. Clinical studies on patients with acne, including three-dimensional (3D) cultures of primary keratinocytes, are required to develop new diagnostic markers for determining the severity of acne vulgaris.

Identification of 2,4-Di-tert-Butylphenol as an Antimicrobial Agent Against Cutibacterium acnes Bacteria from Rwandan Propolis

BACKGROUND/OBJECTIVES

Acne is the most prevalent dermatological condition among humans, affecting approximately 80% of adolescents during puberty. To date, numerous compounds have been used for acne treatment, including erythromycin ointments and antiseptics, with varying degrees of success. The emergence of erythromycin-resistant C. acnes strains has spurred the search for new antimicrobial agents, particularly from natural sources.

METHODS

Propolis collected in Rwanda was extracted and fractionated by flash chromatography and tested against C. acnes growth by using NCLSI recommendations.

RESULTS

In our research, we identified a molecule, 2,4-Di-tert-butylphenol (2,4-DTBP) which inhivbited the C. acnes growth at a concentration of 16 µg/mL. Based on these results, we formulated an ointment (1%) using OFAP18 and petroleum jelly for the potential treatment of acne using a mouse model.

CONCLUSIONS

In vitro and in vivo evidence suggests that 2,4-DTBP has anti-inflammatory properties and could effectively manage the overgrowth of C. acnes as well as serve as a potent alternative for the formulation of an active propolis ointment for acne treatment.

Complete genome of single locus sequence typing D1 strain Cutibacterium acnes CN6 isolated from healthy facial skin

OBJECTIVES

Cutibacterium acnes is a Gram-positive bacterium commonly found on human skin, particularly in sebaceous areas. While it is typically considered a commensal, specific strain types based on single locus sequence typing (SLST) have been associated with pathogenic conditions or healthy skin. Recently, SLST D1 strains, part of phylotype IA1, have received attention for their potential benefits related to skin health. However, their genetic characteristics remain underexplored. Therefore, the whole genome of C. acnes CN6, an SLST D1 strain isolated from the facial skin of a healthy individual, was sequenced to expand the understanding of SLST D1 strains and identify genomic features that may support skin health.

DATA DESCRIPTION

The whole genome sequencing of C. acnes CN6 was conducted using MinION reads based on de novo assembly, revealing a single circular complete chromosome. With the length of 2,550,458 bp and G + C content of 60.04%, the genome contains 2,492 genes, including 2,433 CDSs, 9 rRNAs, 46 tRNAs, 4 ncRNAs, and 134 pseudo genes. Previously predicted virulence proteins of C. ances were detected in the genome. Genome comparation with 200 C. acnes strains isolated from healthy facial skin revealed SLST D1 strain-specific genes and a unique variant of the znuC gene in D1 strains.

Cutibacterium acnes invades submicron osteocyte lacuno-canalicular networks following implant-associated osteomyelitis

Cutibacterium acnes, part of normal skin flora, is increasingly recognized as an opportunistic pathogen capable of causing chronic prosthetic joint infections (PJI) associated with total hip and knee arthroplasty. However, there is a paucity of literature examining the pathogenesis of C. acnes during PJI. To study this, we developed an implant-associated osteomyelitis murine model in which 8-10-week-old C57BL6 mice were subjected to transtibial implantation of titanium or stainless-steel L-shaped pins contaminated with C. acnes. Postsurgery, mice were killed on Days 14 and 28 for terminal assessments of (1) bacterial load in bone, implant, and internal organs (heart, spleen, kidney, and liver), (2) bone osteolysis (micro-CT), (3) abscess formation (histology), and (4) systematic electron microscopy (EM). In vitro scanning EM (SEM) confirmed that C. acnes can form biofilms on stainless-steel and titanium implants. In mice, C. acnes could persist for 28 days in the tibia. Also, we observed C. acnes dissemination to internal organs. C. acnes chronic osteomyelitis revealed markedly reduced bone osteolysis and abscess formation compared to Staphylococcus aureus infections. Importantly, transmission EM (TEM) investigation revealed the presence of C. acnes within canaliculi, demonstrating that C. acnes can invade the osteocyte lacuno-canalicular networks (OLCN) within bone. Our preliminary pilot study, for the first time, revealed that the OLCN in bone can be a reservoir for C. acnes and potentially provides a novel mechanism of why C. acnes chronic implant-associated bone infections are difficult to treat.

Octahydroindolizine alkaloid Homocrepidine A from Dendrobium crepidatum attenuate P. acnes-induced inflammatory in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium crepidatum Lindl. ex Paxton is a perennial epiphyte of Dendrobium genus, distributed in southern China, and utilized as the traditional Chinese medicine "Shihu" in Yunnan Province. Due to its heat-clearing and detoxicating properties, it is formulated as the "XiaoCuoWan" as recorded in the China Pharmacopoeia, and specially used to treat chronic skin inflammatory diseases, such as acne.

AIM OF THE STUDY

This research aimed to estimate impact of the octahydroindoline alkaloid Homocrepidine A (HCA), isolated from D. crepidatum, on acne inflammation using both human THP-1 cells and mouse models. Furthermore, the potential anti-inflammatory mechanism of HCA has been analyzed through molecular biology methods and computer simulation.

MATERIALS AND METHODS

THP-1 cells and mouse models induced by live Propionibacterium acnes (P. acnes) were employed to evaluate the anti-inflammatory properties of crude extract of D. crepidatum (DCE) and HCA. ELISA was utilized to detect the release of inflammatory cytokines in both cellular and murine ear tissues. RNAseq was used to screen the pathways associated with HCA-mediated inflammatory inhibition, while Western blot, RT-qPCR, and immunofluorescence were utilized to detect the expression of relevant proteins. Additionally, molecular docking simulations and cellular thermal shift assays were employed to confirm the target of HCA.

RESULTS

Our research shows that DCE and HCA can effectively alleviate acne inflammation. HCA inhibits TLR2 expression by interacting with amino acid residues in the TIR domain of hTLR2, including Pro-681, Asn-688, Trp-684, and Ile-685. Moreover, HCA disrupts inflammatory signal transduction mediated by MAPK and NF-κB pathways through MyD88-dependent pathway. Additionally, HCA treatment facilitates Nrf2 nuclear translocation and upregulates HO-1 expression, thereby inhibiting NLRP3 inflammasomes activation. In vivo experiments further revealed that HCA markedly attenuated erythema and swelling caused by P. acnes in mice ears, while also decreasing the expression of pro-inflammatory cytokines IL-1β and IL-8.

CONCLUSIONS

Our research highlights the protective effects of D. crepidatum and its bioactive compound HCA against acne inflammation, marking the first exploration of its potential in this context. The discoveries indicate that HCA treatment may represent a promising functional approach for acne therapy.

Colonization of Bone Flaps by Cutibacterium acnes During Decompressive Craniectomies for Traumatic and Non-traumatic Indications: A Retrospective Observational Study

Background Cutibacterium acnes (C. acnes) is one of the most common bacteria in the human skin microbiota. Due to it generally requiring special culturing techniques, it was generally not routinely included in culture. However, recent laboratory automation advancements have allowed C. acnes to be a routinely tested pathogen. Though this could improve outcomes by detecting a virulent pathogen early, it has raised concerns about potential false positives leading to increased costs and medical risks. This study aims to analyze the C. acnes colonization rates in traumatic craniectomies and compare it to non-traumatic craniectomies, the former including risk factors due to penetrations and the latter being conceptually similar to a craniotomy with a lack thereof. This would help establish a baseline rate to understand the pathogen's implications better. Methodology We analyzed the electronic health records of 124 patients who underwent a craniectomy followed by a cranioplasty at Inova Health System from January 1, 2018, to January 1, 2023. The following categories of data were recorded for each patient: patient descriptors, comprehensive surgical timelines and outcomes, and bone flap viability and microbial colonization assessment. The chi-squared tests of independence and Wilcoxon signed-rank tests were used to assess statistical significance between groups in the indications underlying surgery (traumatic vs. non-traumatic) with C. acnes colonization, flap status (reimplanted vs. discarded), hospital length of stay (LOS), and unexpected 30-day readmission. Results Traumatic (67%) and non-traumatic (33%) craniectomies were compared. There was no significant association between the two craniectomy etiologies in terms of C. acnes colonization (40% vs. 26.5%, p=0.19), flap discardment (40% vs. 24%, p=0.12), or readmission rates (20% vs. 9.6%, p=0.18). However, a significant association was found between C. acnes colonization and LOS during the index craniectomy procedure (24.8 vs. 25.9 days, p=0.049), indicating that colonization may influence LOS. No significant association was found between the type of cranial surgery and LOS (p=0.83), suggesting other factors may play a more crucial role in determining LOS. The findings highlight the need to consider the impact of C. acnes colonization on surgical outcomes and hospital protocols. Conclusion Our findings illustrate that there is no significant difference between C. acnes colonization in traumatic and non-traumatic craniectomies; therefore, C. acnes can be expected to be cultured at a baseline level regardless of the etiology. Furthermore, there was no association with surgical indication and flap status, LOS, and readmission rates. However, a significant association was found between C. acnes status and LOS, indicating the increased complexity of care associated with the pathogen's detection. These findings support the protocol of deferring C. acnes culturing unless specific concerns are found.

Acne and the cutaneous microbiome: A systematic review of mechanisms and implications for treatments

Acne vulgaris is a pervasive skin disease characterized by inflammation of sebaceous units surrounding hair follicles. It results from the complex interplay between skin physiology and the intricate cutaneous microbiome. Current acne treatments, while effective, have major limitations, prompting a shift towards microbiome-based therapeutic approaches. This study aims to determine the relationship between acne and the cutaneous microbiome, assess the effects of current treatments on the cutaneous microbiome and explore the implications for developing new therapies. A systematic review was performed using PubMed and SCOPUS databases within the last 10 years. Methodological quality was assessed independently by two authors. The search retrieved 1830 records, of which 26 articles met the inclusion criteria. Meta-analysis of alpha diversity change was assessed using fixed and randomized effect models per therapeutic group. Eight studies pertain to the role of the cutaneous microbiome in acne, identifying C. acnes, S. aureus and S. epidermidis as key contributors through overproliferation, commensalism or dysbiosis. Eleven studies discuss current acne treatments, including doxycycline (1), topical benzoyl peroxide (BPO) (4), isotretinoin (2), sulfacetamide-sulfur (SSA) (2) and aminolevulinic acid-photodynamic therapy (ALA-PDT) (2), identified as modulating the cutaneous microbiome as a mechanism of efficacy in acne treatment. Seven studies discuss new treatments with topical probiotics, plant derivatives and protein derivatives, which contribute to acne clearance via modulation of dysbiosis, inflammatory markers and diversity indexes. A meta-analysis of the effects of existing therapeutics on the cutaneous microbiome identified benzoyl peroxide as the only treatment to facilitate significant change in diversity. Despite the heterogeneity of study types and microbiome classifications limiting the analysis, this review underscores the complexity of microbial involvement in acne pathogenesis. It delineates the effects of acne therapeutics on microbial diversity, abundance and composition, emphasizing the necessity for personalized approaches in acne management based on microbiome modulation.

Isolation, genomic analysis and functional characterization of Enterococcus rotai CMTB-CA6, a putative probiotic strain isolated from a medicinal plant Centella asiatica

Probiotics and their derivatives offer significant health benefits by supporting digestive health, boosting the immune system, and regulating the microbiomes not only of the internal gastrointestinal track but also of the skin. To be effective, probiotics and their derivatives must exhibit robust antimicrobial activity, resilience to adverse conditions, and colonization capabilities in host tissues. As an alternative to animal-derived probiotics, plant-derived lactic acid bacteria (LAB) present promising advantages, including enhanced diversity and tolerance to challenging environments. Our study focuses on exploring the potential of plant-derived LAB, particularly from the medicinal plant Centella asiatica, in improving skin conditions. Through a bacterial isolation procedure from C. asiatica leaves, Enterococcus rotai CMTB-CA6 was identified via 16S rRNA sequencing, whole genome sequencing, and bioinformatic analyses. Based on genomic analysis, antimicrobial-resistance and virulence genes were not detected. Additionally, the potential functions of E. rotai CMTB-CA6 were characterized by its lysates' ability to regulate skin microbes, such as stimulating the growth of Staphylococcus epidermidis while inhibiting that of Cutibacterium acnes, to restore the viability of human dermal fibroblasts under inflammatory conditions, and to demonstrate effective antioxidant activities both in a cell-free system and in human dermal fibroblasts. Our investigation revealed the efficacy of E. rotai CMTB-CA6 lysates in improving skin conditions, suggesting its potential use as a probiotic-derived agent for skin care products. Considering the ecological relationship between plant-inhabited bacteria and their host plants, we suggest that the utilization of E. rotai CMTB-CA6 strain for fermenting its host plant, C. asiatica, could be a novel approach to efficiently enriching bioactive molecules for human health benefits.

Cutibacterium acnes as an overseen autoimmunity trigger: Unearthing heat-shock driven molecular mimicry

Cutibacterium acnes, common resident of the human skin, can establish both commensal and pathogenic relations with the human host; however, long-term consequences of C. acnes-induced inflammation remained un(der)explored. To infer the capacity of triggering autoimmunity in humans via molecular mimicry, a comprehensive immunoinformatics analysis of the experimentally characterized C. acnes proteome was performed. The protocol included homology screening between the C. acnes and the human proteome, and validation of shared specificity regions against the collection of experimentally characterized T-cell epitopes, related to autoimmunity. To obtain highly reliable predictions, the results were subjected to additional cross-validation by a dedicated MHC-restriction analysis, including a docking study of C. acnes mimotopes and human counterparts with the highest degree of sequence similarity to MHCII molecules representing the highest risk for detected autoimmune pathologies. Due to mimicking of highly immunogenic, but also evolutionary conserved autoantigens from the Heat Shock protein family, association between C. acnes and the pathogenesis of highly incident autoimmune diseases: Type 1 Diabetes, Rheumatoid Arthritis, and Juvenile Idiopathic Arthritis, was found. To the best of our knowledge, this study is the first one to provide preliminary information and a mechanistic link on the putative involvement of C. acnes in the pathogenesis of autoimmunity in humans.

Metagenomic identification of bull semen microbiota in different seasons

A seasonal effect on sperm quality parameters was observed previously. Although identification of the bull semen microbiota by 16S rRNA sequencing was performed previously, it has not been carried out in commercial semen samples from different seasons, and its connection with sperm quality parameters has not been evaluated yet. The objectives in this study were; (i) to evaluate diversity of bull semen microbiota and sperm quality parameters in different seasons, and (ii) to find if specific bacteria were associated with seasonal differences in specific sperm quality parameters. Bull semen microbiota was identified in 54 commercial bull semen samples from 3 seasons (winter, spring, summer). Sperm quality was analysed by Computer Assisted Sperm Analyses (CASA) and Flow Cytometry (FC). From 28 phyla in all samples, six phyla were identified in samples from all seasons, with observed seasonal differences in their distribution. At genus level, 388 genera were identified, of which 22 genera had a relative abundance over 1 % and showed seasonal differences in bacterial diversity, and 9 bacteria genera were present in all seasons. Differences between spring and summer (P < 0.05) were observed for live hydrogen peroxide positive sperm cells. A trend towards significance (0.10 > P > 0.05) was observed for some CASA kinematics (VCL and LIN) and FC parameters (High respiratory activity, and live hydrogen peroxide positive sperm cells) between seasons. Nevertheless, associations between sperm quality parameters and specific bacteria were observed in spring.

Management of periprosthetic joint infection of the shoulder: A narrative review

Evidence for management of shoulder periprosthetic joint infection (PJI) has traditionally originated from the hip and knee literature. The differing microbiome, anatomy and implants used in the shoulder mean this evidence is not always directly transferrable. The 2018 Philadelphia International Consensus Meeting for the first-time produced evidence-based guidelines and diagnostic criteria relating specifically to PJI of the shoulder. These guidelines and criteria recognize the pathogenicity of lower virulence organisms in the shoulder which often means clinical presentation is less obvious than other joints. The role of Cutibacterium acnes in shoulder PJI is the subject of increasing basic science and clinical research and advances in microbiological research may help to understand the pathology behind shoulder infections. There is new evidence that outcomes after revision shoulder arthroplasty are dependent on the virulence of the causative organism. An individualised approach to treatment considering host factors, organism, soft tissues and bone stock is recommended. Debate continues in the literature regarding the indications of one- or two-stage revision and the latest evidence is discussed and synthesized in this review article. We advocate careful multidisciplinary team decision making for cases of shoulder PJI and recognize a limited role for debridement and implant retention in acute shoulder PJI (<6 weeks). There appears to be a role for one-stage revision in lower risk cases with low virulence organisms but caution against its' universal adoption. In higher risk or complex cases, there remains a clear role for two-stage revision arthroplasty, and we detail the specifics of this protocol and procedure from our tertiary shoulder and elbow unit.

A New Generation of Postbiotics for Skin and Scalp: In Situ Production of Lipid Metabolites by Malassezia

Effects of pre- and probiotics on intestinal health are well researched and microbiome-targeting solutions are commercially available. Even though a trend to appreciate the presence of certain microbes on the skin is seeing an increase in momentum, our understanding is limited as to whether the utilization of skin-resident microbes for beneficial effects holds the same potential as the targeted manipulation of the gut microflora. Here, we present a selection of molecular mechanisms of cross-communication between human skin and the skin microbial community and the impact of these interactions on the host's cutaneous health with implications for the development of skin cosmetic and therapeutic solutions. Malassezia yeasts, as the main fungal representatives of the skin microfloral community, interact with the human host skin via lipid mediators, of which several are characterized by exhibiting potent anti-inflammatory activities. This review therefore puts a spotlight on Malassezia and provides a comprehensive overview of the current state of knowledge about these fungal-derived lipid mediators and their capability to reduce aesthetical and sensory burdens, such as redness and itching, commonly associated with inflammatory skin conditions. Finally, several examples of current skin microbiome-based interventions for cosmetic solutions are discussed, and models are presented for the use of skin-resident microbes as endogenous bio-manufacturing platforms for the in situ supplementation of the skin with beneficial metabolites.

Pro-inflammatory activity of Cutibacterium acnes phylotype IA1 and extracellular vesicles: An in vitro study

Acne is a chronic inflammatory skin condition that involves Cutibacterium acnes (C. acnes), which is classified into six main phylotypes (IA1, IA2, IB, IC, II and III). Acne development is associated with loss of C. acnes phylotype diversity, characterised by overgrowth of phylotype IA1 relative to other phylotypes. It was also shown that purified extracellular vesicles (EVs) secreted by C. acnes can induce an acne-like inflammatory response in skin models. We aimed to determine if the inflammatory profile of EVs secreted by C. acnes phylotype IA1 from an inflammatory acne lesion was different from C. acnes phylotype IA1 from normal skin, thus playing a direct role in the severity of inflammation. EVs were produced in vitro after culture of two clinical strains of C. acnes phylotype IA1, T5 from normal human skin and A47 from an inflammatory acne lesion, and then incubated with either human immortalised keratinocytes, HaCaT cells, or skin explants obtained from abdominoplasty. Subsequently, quantitative PCR (qPCR) was performed for human β-defensin 2 (hBD2), cathelicidin (LL-37), interleukin (IL)-1β, IL-6, IL-8, IL-17α and IL-36γ, and ELISA for IL-6, IL-8 and IL-17α. We found that EVs produced in vitro by C. acnes derived from inflammatory acne lesions significantly increased the pro-inflammatory cytokines and anti-microbial peptides at both transcriptional and protein levels compared with EVs derived from normal human skin. We show for the first time that C. acnes EVs from inflammatory acne play a crucial role in acne-associated inflammation in vitro and that C. acnes phylotype IA1 collected from inflammatory acne lesion and normal skin produce different EVs and inflammatory profiles in vitro.

Anti-CAMP1 IgG promotes macrophage phagocytosis of Cutibacterium acnes type II

Among 5 types of the Christie-Atkins-Munch-Petersen factor (CAMP) of Cutibacterium acnes, CAMP1 is highly expressed in phylotype II as well as IB, and thought to be a virulence factor of opportunistic but fatal blood, soft tissue, and implant-related infections. The target of a human single-chain variable antibody fragment (scFv), recently isolated from a phage display library, has been identified as CAMP1 of phylotype II, using immunoprecipitation followed by mass spectrometry, phage display peptide biopanning, 3D-modelling, and ELISA. The IgG1 format of the antibody could enhance phagocytosis of C. acnes DMST 14916 by THP-1 human monocytes. Our results suggest that the antibody-dependent phagocytosis process is mediated by the caveolae membrane system and involves the induction of IL-1β. This is the first report on the study of a human antibody against CAMP1 of C. acnes phylotype II, of which a potential use as therapeutic antibody against virulence C. acnes infection is postulated.

Multi-omics signatures reveal genomic and functional heterogeneity of Cutibacterium acnes in normal and diseased skin

Cutibacterium acnes is the most abundant bacterium of the human skin microbiome since adolescence, participating in both skin homeostasis and diseases. Here, we demonstrate individual and niche heterogeneity of C. acnes from 1,234 isolate genomes. Skin disease (atopic dermatitis and acne) and body site shape genomic differences of C. acnes, stemming from horizontal gene transfer and selection pressure. C. acnes harbors characteristic metabolic functions, fewer antibiotic resistance genes and virulence factors, and a more stable genome compared with Staphylococcus epidermidis. Integrated genome, transcriptome, and metabolome analysis at the strain level unveils the functional characteristics of C. acnes. Consistent with the transcriptome signature, C. acnes in a sebum-rich environment induces toxic and pro-inflammatory effects on keratinocytes. L-carnosine, an anti-oxidative stress metabolite, is up-regulated in the C. acnes metabolome from atopic dermatitis and attenuates skin inflammation. Collectively, our study reveals the joint impact of genes and the microenvironment on C. acnes function.

Impact of Prophylactic Antibiotic Use in Ornamental Fish Tanks on Microbial Communities and Pathogen Selection in Carriage Water in Hong Kong Retail Shops

Antibiotics are routinely added to ornamental fish tanks for treating bacterial infection or as a prophylactic measure. However, the overuse or subtherapeutical application of antibiotics could potentially facilitate the selection of antibiotic resistance in bacteria, yet no studies have investigated antibiotic use in the retail ornamental fish sector and its impact on microbial communities. The present study analyzed the concentrations of twenty antibiotics in the carriage water (which also originates from fish tanks in retail shops) collected monthly from ten local ornamental fish shops over a duration of three months. The antibiotic concentrations were correlated with the sequenced microbial community composition, and the risk of resistance selection in bacteria was assessed. Results revealed that the detected concentrations of tetracyclines were the highest among samples, followed by fluoroquinolones and macrolides. The concentrations of oxytetracycline (44.3 to 2,262,064.2 ng L-1) detected across three months demonstrated a high risk for resistance selection at most of the sampled shops. Zoonotic pathogens (species of Rhodococcus, Legionella, and Citrobacter) were positively correlated with the concentrations of oxytetracycline, tetracycline, chlortetracycline, and enrofloxacin. This suggests that antibiotic use in retail shops may increase the likelihood of selecting for zoonotic pathogens. These findings shed light on the potential for ornamental fish retail shops to create a favorable environment for the selection of pathogens with antibiotics, thereby highlighting the urgent need for enhanced antibiotic stewardship within the industry.

Acid-treated Staphylococcus aureus induces acute silkworm hemolymph melanization

The skin microbiome maintains healthy human skin, and disruption of the microbiome balance leads to inflammatory skin diseases such as folliculitis and atopic dermatitis. Staphylococcus aureus and Cutibacterium acnes are pathogenic bacteria that simultaneously inhabit the skin and cause inflammatory diseases of the skin through the activation of innate immune responses. Silkworms are useful invertebrate animal models for evaluating innate immune responses. In silkworms, phenoloxidase generates melanin as an indicator of innate immune activation upon the recognition of bacterial or fungal components. We hypothesized that S. aureus and C. acnes interact to increase the innate immunity-activating properties of S. aureus. In the present study, we showed that acidification is involved in the activation of silkworm hemolymph melanization by S. aureus. Autoclaved-killed S. aureus (S. aureus [AC]) alone does not greatly activate silkworm hemolymph melanization. On the other hand, applying S. aureus [AC] treated with C. acnes culture supernatant increased the silkworm hemolymph melanization. Adding C. acnes culture supernatant to the medium decreased the pH. S. aureus [AC] treated with propionic acid, acetic acid, or lactic acid induced higher silkworm hemolymph melanization activity than untreated S. aureus [AC]. S. aureus [AC] treated with hydrochloric acid also induced silkworm hemolymph melanization. The silkworm hemolymph melanization activity of S. aureus [AC] treated with hydrochloric acid was inhibited by protease treatment of S. aureus [AC]. These results suggest that acid treatment of S. aureus induces innate immune activation in silkworms and that S. aureus proteins are involved in the induction of innate immunity in silkworms.

Comprehensive lipidomic analysis of the genus Cutibacterium

Cutibacterium are part of the human skin microbiota and are opportunistic microorganisms that become pathogenic in immunodeficient states. These lipophilic bacteria willingly inhabit areas of the skin where sebaceous glands are abundant; hence, there is a need to thoroughly understand their metabolism. Lipids are no longer considered only structural elements but also serve as signaling molecules and may have antigenic properties. Lipidomics remains a major research challenge, mainly due to the diverse physicochemical properties of lipids. Therefore, this study aimed to perform a large comparative lipidomic analysis of eight representatives of the Cutibacterium genus, including four phylotypes of C. acnes and two strains of C. granulosum, C. avidum, and C. namnetense. Lipidomic analysis was performed by liquid chromatography‒mass spectrometry (LC-MS) in both positive and negative ion modes, allowing the detection of the widest range of metabolites. Fatty acid analysis by gas chromatography‒mass spectrometry (GC-MS) corroborated the lipidomic data. As a result, 128 lipids were identified, among which it was possible to select marker compounds, some of which were characteristic even of individual C. acnes phylotypes. These include phosphatidylcholine PC 30:0, sphingomyelins (SM 33:1, SM 35:1), and phosphatidylglycerol with an alkyl ether substituent PG O-32:0. Moreover, cardiolipins and fatty acid amides were identified in Cutibacterium spp. for the first time. This comparative characterization of the cutibacterial lipidome with the search for specific molecular markers reveals its diagnostic potential for clinical microbiology.

IMPORTANCE

Cutibacterium (previously Propionibacterium) represents an important part of the human skin microbiota, and its role in clinical microbiology is growing due to opportunistic infections. Lipidomics, apart from protein profiling, has the potential to prove to be a useful tool for defining the cellular fingerprint, allowing for precise differentiation of microorganisms. In this work, we presented a comparative analysis of lipids found in eight strains of the genus Cutibacterium, including a few C. acnes phylotypes. Our results are one of the first large-scale comprehensive studies regarding the bacterial lipidome, which also enabled the selection of C. acnes phylotype-specific lipid markers. The increased role of lipids not only as structural components but also as diagnostic markers or potential antigens has led to new lipid markers that can be used as diagnostic tools for clinical microbiology. We believe that the findings in our paper will appeal to a wide range of researchers.

Investigation into the Anti-Acne Effects of Castanea sativa Mill Leaf and Its Pure Ellagitannin Castalagin in HaCaT Cells Infected with Cutibacterium acnes

Acne vulgaris is a prevalent skin disorder affecting many young individuals, marked by keratinization, inflammation, seborrhea, and colonization by Cutibacterium acnes (C. acnes). Ellagitannins, known for their antibacterial and anti-inflammatory properties, have not been widely studied for their anti-acne effects. Chestnut (Castanea sativa Mill., C. sativa), a rich ellagitannin source, including castalagin whose acne-related bioactivity was previously unexplored, was investigated in this study. The research assessed the effect of C. sativa leaf extract and castalagin on human keratinocytes (HaCaT) infected with C. acnes, finding that both inhibited IL-8 and IL-6 release at concentrations below 25 μg/mL. The action mechanism was linked to NF-κB inhibition, without AP-1 involvement. Furthermore, the extract displayed anti-biofilm properties and reduced CK-10 expression, indicating a potential role in mitigating inflammation, bacterial colonization, and keratosis. Castalagin's bioactivity mirrored the extract's effects, notably in IL-8 inhibition, NF-κB inhibition, and biofilm formation at low μM levels. Other polyphenols, such as flavonol glycosides identified via LC-MS, might also contribute to the extract's biological activities. This study is the first to explore ellagitannins' potential in treating acne, offering insights for developing chestnut-based anti-acne treatments pending future in vivo studies.

Interplay of xenobiotic-degrading and antibiotic-resistant microorganisms among the microbiome found in the air, handrail, and floor of the subway station

Investigating the quality of the subway environment, especially regarding antibiotic resistance genes (ARGs) and xenobiotics, conveys ecological and health impacts. In this study, compositions and relations of microorganisms harboring ARGs and xenobiotic degradation and metabolism genes (XDGs) in the Sukhumvit subway station (MRT-SKV) in Bangkok was assessed by analyzing the taxonomic and genetic diversity of the microbiome in the air and on the surfaces of floor and handrail. The major bacteria in the MRT-SKV (including Moraxella, which was abundant in the bioaerosol and handrail samples, and Staphylococcus, which was abundant in the bioaerosol samples) were found to contain both ARGs and XDGs. The co-abundance correlation network revealed notable relationships among bacteria harboring antibiotic resistance genes (ARGs) and xenobiotic degradation genes (XDGs). Significant associations were observed between ARGs linked to glycopeptide and fluoroquinolone resistance and genes associated with benzoate, styrene, and atrazine degradation pathways, as well as between ARGs related to cephamycin, cephalosporin, and MLS resistance and XDGs associated with the cytochrome P450-dependent drug metabolism pathway. These correlations suggested that selective pressure exerted by certain xenobiotics and antibiotics can simultaneously affect both ARGs and XDGs in the environment and should favor correlations and co-survival among ARG- and XDG-containing bacteria in the environments. The correlations may occur via shared mechanisms of resistance to both xenobiotics and antibiotics. Finally, different correlation pairs were seen in different niches (air, handrail, floor) of the subway environment or different geolocations. Thus, the relationship between ARG and XDG pairs most likely depends on the unique characteristics of the niches and on the prominent types of xenobiotics and antibiotics in the subway environment. The results indicated that interactions and connections between microbial communities can impact how they function. These microorganisms can have profound effects on accumulation of xenobiotics and ARGs in the MRT-SKV.

Longitudinal profiling of the microbiome at four body sites reveals core stability and individualized dynamics during health and disease

To understand the dynamic interplay between the human microbiome and host during health and disease, we analyzed the microbial composition, temporal dynamics, and associations with host multi-omics, immune, and clinical markers of microbiomes from four body sites in 86 participants over 6 years. We found that microbiome stability and individuality are body-site specific and heavily influenced by the host. The stool and oral microbiome are more stable than the skin and nasal microbiomes, possibly due to their interaction with the host and environment. We identify individual-specific and commonly shared bacterial taxa, with individualized taxa showing greater stability. Interestingly, microbiome dynamics correlate across body sites, suggesting systemic dynamics influenced by host-microbial-environment interactions. Notably, insulin-resistant individuals show altered microbial stability and associations among microbiome, molecular markers, and clinical features, suggesting their disrupted interaction in metabolic disease. Our study offers comprehensive views of multi-site microbial dynamics and their relationship with host health and disease.

Dyslipidaemia is associated with Cutibacterium acnes hip and knee prosthetic joint infection

PURPOSE

Optimization of medical factors including diabetes and obesity is a cornerstone in the prevention of prosthetic joint infection (PJI). Dyslipidaemia is another component of metabolic syndrome which has not been thoroughly investigated as an individual, modifiable risk factor. This study examined the association of dyslipidaemia with PJI caused by the lipophilic microbe Cutibacterium acnes (C. acnes).

METHODS

A retrospective chart review examined patients with positive C. acnes culture at hip or knee arthroplasty explantation. A control group with methicillin-sensitive Staphylococcus aureus (MSSA) positive cultures at explantation was matched for age, sex, and surgical site, as well as a second control group with no infection. A total of 80 patients were included, 16 with C. acnes, 32 with MSSA, and 32 with no infection. All patients had a lipid panel performed within one year of surgery. Lipid values and categories were compared using multinomial logistic regressions.

RESULTS

High or borderline triglycerides (TG) (relative risk ratio (RRR) = 0.13; P = 0.013) and low high-density lipoprotein (HDL) (RRR = 0.13; P = 0.025) were significantly associated with C. acnes PJI compared to MSSA-PJI. High or borderline TG (RRR = 0.21; P = 0.041) and low HDL (RRR = 0.17; P = 0.043) were also associated with a greater probability of C. acnes infection compared to no infection.

CONCLUSIONS

The presence of elevated TG and low HDL were both associated at a statistically significant level with C. acnes hip or knee PJI compared to controls with either MSSA PJI or no infection. This may represent a specific risk factor for C. acnes PJI that is modifiable.

Intracerebroventricular Cutibacterium acnes Generates Manifestations of Alzheimer's Disease-like Pathology in the Rat Hippocampus

The infection hypothesis is a new causative explanation for Alzheimer's disease (AD). In recent decades, various species of bacterial pathogens have been distinguished in the autopsy of Alzheimer's patients; however, the mechanism of bacterial contribution to AD pathology is still unknown. To explore the hypothesis, Cutibacterium acnes (C. acnes) was selected, and effects of its intracerebroventricular (ICV) inoculation in rats was evaluated. The results revealed that C. acnes causes memory impairment, which might be a consequence of upregulated Amyloid β (Aβ) deposits in the hippocampus; Aβ aggregates are co-localized with C. acnes colonies. The key point of our hypothesis is that the activation of the innate immune system by C. acnes through the TLR2/NF-κB/NLRP3 signaling pathway, eventually leads to increased neuroinflammation, which might be resulted from microgliosis and astrogliosis. Neuroinflammation increases oxidative stress and cell apoptosis. Overall, the obtained results of this study support our hypothesis that brain exposure to C. acnes prompted neuroinflammation with similar AD-like pathology.

Fog caused distinct diversity of airborne bacterial communities enriched with pathogens over central Indo-Gangetic plain in India

Fog causes enhancement of bacterial loading in the atmosphere. Current study represents the impact of occurrences of fog on the alteration of diversity of airborne bacteria and their network computed from metagenomic data of airborne samples collected at Arthauli (25.95°N, 85.10°E) situated at central Indo-Gangetic Plain (IGP) during 1-14 January 2021. A distinct bacterial diversity with a complex network is identified in foggy condition due to the enrichment of unique types of bacteria. Present investigation highlights a statistically significant enrichment of airborne pathogenic bacteria found in a unique ecosystem within air evolved due to the occurrences of fog over central IGP. In the foggy network, Cutibacterium, an opportunistic pathogen, is identified to be interacting maximum (21 edges) with other bacteria with statistically significant copresence relation, which are responsible for various infections for human beings. A 40-60% increase (p < 0.01) in the abundance of pathogenic bacteria for respiratory and skin diseases is noticed in fog period. Among the fog-enriched bacteria, Cutibacterium, Herbaspirillum, Paenibacillus, and Tsukamurella are examples of opportunistic bacteria causing various respiratory diseases, while Paenibacillus can even cause skin cancer and acute lymphoblastic leukemia.

Longitudinal profiling of the microbiome at four body sites reveals core stability and individualized dynamics during health and disease

To understand dynamic interplay between the human microbiome and host during health and disease, we analyzed the microbial composition, temporal dynamics, and associations with host multi-omics, immune and clinical markers of microbiomes from four body sites in 86 participants over six years. We found that microbiome stability and individuality are body-site-specific and heavily influenced by the host. The stool and oral microbiome were more stable than the skin and nasal microbiomes, possibly due to their interaction with the host and environment. Also, we identified individual-specific and commonly shared bacterial taxa, with individualized taxa showing greater stability. Interestingly, microbiome dynamics correlated across body sites, suggesting systemic coordination influenced by host-microbial-environment interactions. Notably, insulin-resistant individuals showed altered microbial stability and associations between microbiome, molecular markers, and clinical features, suggesting their disrupted interaction in metabolic disease. Our study offers comprehensive views of multi-site microbial dynamics and their relationship with host health and disease.

Study Highlights

The stability of the human microbiome varies among individuals and body sites.Highly individualized microbial genera are more stable over time.At each of the four body sites, systematic interactions between the environment, the host and bacteria can be detected.Individuals with insulin resistance have lower microbiome stability, a more diversified skin microbiome, and significantly altered host-microbiome interactions.

Sebum Components Dampen the Efficacy of Skin Disinfectants against Cutibacterium acnes Biofilms

At Canadian Blood Services, despite the use of 2% chlorhexidine and 70% isopropyl alcohol (standard disinfectant, SD) prior to venipuncture, Cutibacterium acnes evades eradication and is a major contaminant of platelet concentrates (PCs). Since C. acnes forms bacterial aggregates known as biofilms in the sebaceous niches of the skin, this study aimed to assess whether sebum-like components impact disinfectant efficacy against C. acnes leading to its dominance as a PC contaminant. C. acnes mono-species and dual-species biofilms (C. acness and a transfusion-relevant Staphylococcus aureus isolate) were formed in the presence and absence of sebum-like components and exposed to SD, a hypochlorous acid-based disinfectant (Clinisept+, CP), or a combination of both disinfectants to assess disinfectant efficacy. Our data indicate that sebum-like components significantly reduce the disinfectant efficacy of all disinfectant strategies tested against C. acnes in both biofilm models. Furthermore, though none of the disinfectants led to bacterial eradication, the susceptibility of C. acnes to disinfectants was heightened in an isolate-dependent manner when grown in the presence of S. aureus. The reduction of skin disinfection efficacy in the presence of sebum may contribute to the overrepresentation of C. acnes as a PC contaminant and highlights the need for improved disinfection strategies.

Antimicrobial Properties Related to Anti-Acne and Deodorant Efficacy of Hedychium coronarium J. Koenig Extracts from Pulsed Electric Field Extraction

This study investigated the potential of pulsed electric field (PEF) extraction in enhancing the antimicrobial properties related to anti-acne and deodorant properties of Hedychium coronarium extract. The dried leaf and rhizome of H. coronarium were extracted using 95% v/v ethanol through both conventional solvent extraction and PEF extraction techniques (10, 14, and 20 kV/cm). The chemical composition of the extracts was analyzed. The antimicrobial activities, specifically in relation to acne treatment against Cutibacterium acnes and deodorant properties against Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Pseudomonas aeruginosa, and Escherichia coli, were determined. The irritation profile of was evaluated using the hen's egg chorioallantoic membrane test. The results showed that PEF extraction increased the extract yield, particularly at an electric field strength of 20 kV/cm. Furthermore, PEF extraction significantly enhanced the ellagic acid content, particularly in the leaf extract. Furthermore, the leaf extract demonstrated stronger inhibitory effects against microorganisms associated with body odor and acne compared to the rhizome extract. Notably, all extracts exhibited no signs of irritation, indicating their safety. Overall, the findings suggest that PEF extraction from H. coronarium enhances yield, bioactive compound content, and antimicrobial effects. This indicates the potential of the extract for acne treatment and deodorant use.

Tumor-isolated Cutibacterium acnes as an effective tumor suppressive living drug

The two major challenges in cancer treatment are reducing the side effects and minimizing the cost of cancer treatment. A better therapy to treat cancer remains to be developed despite the presence of many therapeutic options. Here, we present bacterial therapy for treating cancer using tumor-isolated Cutibacterium acnes, which is safe to use, has minimal side effects compared to chemotherapeutic drugs, and most importantly, targets the tumor microenvironment due to the bacterium's anaerobic nature. It activates the immune system, and the immune cells effectively penetrate through the tumor tissue and form an immunologic hub inside, explicitly targeting the tumor and destroying the cells. This bacterial therapy is a new cost-effective innovative treatment.

Comparative Genomic Analysis of Cutibacterium spp. Isolates in Implant-Associated Infections

Bacteria of the genus Cutibacterium are Gram-positive commensals and opportunistic pathogens that represent a major challenge in the diagnosis and treatment of implant-associated infections (IAIs). This study provides insight into the distribution of different sequence types (STs) of C. acnes, and the presence of virulence factors (VFs) in 64 Cutibacterium spp. isolates from suspected or confirmed IAIs obtained during routine microbiological diagnostics. Fifty-three C. acnes, six C. avidum, four C. granulosum, and one C. namnetense isolate, collected from different anatomical sites, were included in our study. Using whole-genome sequencing and a single-locus sequencing typing scheme, we successfully characterized all C. acnes strains and revealed the substantial diversity of STs, with the discovery of six previously unidentified STs. Phylotype IA1, previously associated with both healthy skin microbiome and infections, was the most prevalent, with ST A1 being the most common. Some minor differences in STs' distribution were observed in correlation with anatomical location and association with infection. A genomic analysis of 40 investigated VFs among 64 selected strains showed no significant differences between different STs, anatomical sites, or infection-related and infection undetermined/unlikely groups of strains. Most differences in VF distribution were found between strains of different Cutibacterium spp., subspecies, and phylotypes, with CAMP factors, biofilm-related VFs, lipases, and heat shock proteins identified in all analyzed Cutibacterium spp.

Topical Application of Skin Biome Care Regimen Containing Live Cultures and Ferments of Cutibacterium acnes defendens strain XYCM42 and the Impact on Clinical Outcomes Following Microneedle-induced Skin Remodeling

Background

The skin, our body's largest organ, hosts a complex microbiome that plays a pivotal role in maintaining health and protecting against pathogens. Even slight disruptions to this delicate balance can influence skin health and disease. Among the diverse microbial community, Cutibacterium acnes (C. acnes) subspecies defendens is known for its positive contribution to skin health. However, the interaction between living microbe probiotics and wound healing after aesthetic procedures, such as microneedling, remains unexplored.

Methods

Our study included 40 participants with acne scars who underwent four microneedling sessions spaced three weeks apart. They were randomly assigned to Group 1, receiving a regimen with live C. acnes defendens strain XYCM42, or Group 2, following a conventional skincare routine with a cleanser, moisturizer, and sunscreen. Our study assessed various endpoints, including the Clinician's Global Aesthetic Improvement Scale (CGAIS), clinical safety, improvement in acne scars using Goodman and Baron's Qualitative and Quantitative Acne Scars Grading Scale and Subject's Global Aesthetic Improvement Scale (SGAIS).

Results

Our analysis of live and photo grading data for CGAIS unveiled a statistically significant difference between the two groups, with Group 1 (XYCM42-based regimen) showing remarkable improvement. A similar positive trend was observed in the photo grading for CGAIS. Additionally, participant diaries indicated that Group 1 experienced a faster decline in posttreatment parameters, including erythema, swelling, burning/tingling, and itching.

Conclusion

Integrating a microbiome-optimized, probiotic XYCM42-based regimen with microneedling demonstrated a high safety profile and enhanced treatment outcomes. These findings mark a milestone in aesthetic dermatology, supporting innovative microbiome-based approaches to improve skin health and aesthetics.

Use of Interleukin-12/23 Inhibitor for the Management of Acne Fulminans

Acne fulminans (AF) is a rare disorder marked by severe eruptions of inflamed nodules, hemorrhagic crusts, and ulcers accompanied by systemic symptoms and often laboratory abnormalities. Commonly affecting adolescent males with pre-existing acne, AF has been associated with isotretinoin therapy and elevated testosterone levels. With unknown pathogenesis, lesions frequently involve the trunk and face and are managed standardly with corticosteroids and isotretinoin. Uncontrolled or recurrent cases pose challenges due to prolonged high-dose corticosteroid use with increased scarring. In this study, we present a case of AF in a 17-year-old male unresponsive to corticosteroid and isotretinoin therapy, successfully treated with ustekinumab, an interleukin (IL)-12/23 inhibitor. The introduction of ustekinumab facilitated a controlled corticosteroid taper and isotretinoin dose escalation, resulting in significant clinical improvement of skin lesions and systemic symptoms. This case report underscores the potential of ustekinumab as a viable therapeutic option in the treatment of AF, particularly in cases where corticosteroid and isotretinoin combination therapy have proven ineffective.

Dual RNA-Seq reveals transcriptionally active microbes (TAMs) dynamics in the serum of dengue patients associated with disease severity

Introduction

Dengue virus (DENV) is a flavivirus that has emerged as a global health threat, characterized by either asymptomatic or mild self-limiting febrile illness, but a subset of DENV outbreaks have been associated with severe disease. Studies have looked into the host immune response and dengue viral load during infection. However, it remains unknown how the active microbial isolates modulate the dengue viral infection. In this study, we demonstrate the significance of in-depth analysis of microbiota composition in the serum samples of dengue-infected patients.

Materials and methods

RNA was extracted from the serum samples collected from 24 dengue positive patients. The human mapped reads generated through RNA-Sequencing (RNA-Seq) were removed, while the unmapped (non-human) reads were employed for microbial taxonomic classification using Kraken2 and Bracken2. Further, we assessed the initial blood parameters analyzing the complete blood count (CBC) profile of the patients.

Results

Findings revealed differential abundance of commensals and pathogenic microbes in the early febrile period of hospitalized dengue patients, segregated into, High Viral Reads (HVR) and Low Viral Reads (LVR). The Campylobacter genus was abundant in the HVR whereas Lactobacillus dominated the LVR patients. At species level, the microbiota of HVR exhibited higher abundance of unique potential opportunistic microbes, compared to the commensal microbes' enrichment in the LVR patients'. We hypothesize that the DENV might alter the microbiota composition as observed by the increase in preponderance of opportunistic pathogens and an absence of commensals in the HVR. The presence of commensals in the LVR might explain, i) overall lower dengue viral reads compared to the HVR, and ii) shift in lymphocytes (high) and neutrophils (low) counts; resulting in a comparatively milder clinical manifestation in this group. Our findings may help in understanding the co-infection aspect that will be important to develop dengue therapeutics and vaccines.

Discussion

This study highlights the potential of the unexplored roles of the TAMs in modulating the dengue disease severity using the metatranscriptomic sequencing. This study serves to enhance our understanding of the distinctive microbial and hematologic signatures in the early infection stage that differentiate patients with high viral reads patients from those with low dengue viral reads.

Longitudinal study of the interplay between the skin barrier and facial microbiome over 1 year

Skin is a diverse ecosystem that provides a habitat for microorganisms. The skin condition and the skin microbiome interact each other under diverse environmental conditions. This study was conducted on 10 study participants for a one-year, from September 2020 to August 2021, to investigate the variability of skin microbiome and skin biophysical parameters [TEWL, hydration, and elasticity (R5)] according to season, and to understand the interplay between skin microbiome and skin characteristics. We identified that Cutibacterium, Corynebacterium, Staphyloccocus, unclassified genus within Neisseriaceae, and Streptococcus were major skin microbial taxa at the genus level, and fluctuated with the seasons. Cutibacterium was more abundant in winter, while Corynebacterium, Staphylococcus, and Streptococcus were more abundant in summer. Notably, Cutibacterium and skin barrier parameter, TEWL, exhibited a co-decreasing pattern from winter to summer and showed a significant association between Cutibacterium and TEWL. Furthermore, functional profiling using KEGG provided clues on the impact of Cutibacterium on the host skin barrier. This study enhances our understanding of the skin microbiome and its interplay with skin characteristics and highlights the importance of seasonal dynamics in shaping skin microbial composition.