Human Skin Infections Research Articles

Development of a skin- and neuro-attenuated live vaccine for varicella

Varicella caused by the primary infection of varicella-zoster virus (VZV) exerts a considerable disease burden globally. Current varicella vaccines consisting of the live-attenuated vOka strain of VZV are generally safe and effective. However, vOka retains full neurovirulence and can establish latency and reactivate to cause herpes zoster in vaccine recipients, raising safety concerns. Here, we rationally design a live-attenuated varicella vaccine candidate, v7D. This virus replicates like wild-type virus in MRC-5 fibroblasts and human PBMCs, the carrier for VZV dissemination, but is severely impaired for infection of human skin and neuronal cells. Meanwhile, v7D shows immunogenicity comparable to vOka both in vitro and in multiple small animal species. Finally, v7D is proven well-tolerated and immunogenic in nonhuman primates. Our preclinical data suggest that v7D is a promising candidate as a safer live varicella vaccine with reduced risk of vaccine-related complications, and could inform the design of other herpes virus vaccines.

Antimicrobials from a feline commensal bacterium inhibit skin infection by drug-resistant S. pseudintermedius.

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an important emerging zoonotic pathogen that causes severe skin infections. To combat infections from drug-resistant bacteria, the transplantation of commensal antimicrobial bacteria as a therapeutic has shown clinical promise. We screened a collection of diverse staphylococcus species from domestic dogs and cats for antimicrobial activity against MRSP. A unique strain (S. felis C4) was isolated from feline skin that inhibited MRSP and multiple gram-positive pathogens. Whole genome sequencing and mass spectrometry revealed several secreted antimicrobials including a thiopeptide bacteriocin micrococcin P1 and phenol-soluble modulin beta (PSMβ) peptides that exhibited antimicrobial and anti-inflammatory activity. Fluorescence and electron microscopy revealed that S. felis antimicrobials inhibited translation and disrupted bacterial but not eukaryotic cell membranes. Competition experiments in mice showed that S. felis significantly reduced MRSP skin colonization and an antimicrobial extract from S. felis significantly reduced necrotic skin injury from MRSP infection. These findings indicate a feline commensal bacterium that could be utilized in bacteriotherapy against difficult-to-treat animal and human skin infections.

Ex Vivo Infection of Human Skin with Herpes Simplex Virus 1 Reveals Mechanical Wounds as Insufficient Entry Portals via the Skin Surface.

Herpes simplex virus 1 (HSV-1) enters its human host via the skin and mucosa. The open question is how the virus invades this highly protective tissue in vivo to approach its receptors in the epidermis and initiate infection. Here, we performed ex vivo infection studies in human skin to investigate how susceptible the epidermis and dermis are to HSV-1 and whether wounding facilitates viral invasion. Upon ex vivo infection of complete skin, only sample edges with integrity loss demonstrated infected cells. After removal of the dermis, HSV-1 efficiently invaded the basal layer of the epidermis and, from there, gained access to suprabasal layers. This finding supports a high susceptibility of all epidermal layers which correlated with the surface expression of the receptors nectin-1 and herpesvirus entry mediator (HVEM). In contrast, only single infected cells were detected in the separated dermis, where minor expression of the receptors was found. Interestingly, after wounding, nearly no infection of the epidermis was observed via the skin surface. However, if the wounding of the skin samples led to breaks through the dermis, HSV-1 infected mainly keratinocytes via the damaged dermal layer. The application of latex beads revealed only occasional entry via the wounded dermis; however, it facilitated penetration via the wounded skin surface. Thus, we suggest that although the wounded human skin surface allows particle penetration, the skin still provides barriers that prevent HSV-1 from reaching its receptors. IMPORTANCE The human pathogen herpes simplex virus 1 (HSV-1) invades its host via the skin and mucosa, which leads to primary infection of the epithelium. As the various epithelial barriers effectively protect the tissue against viral invasion, successful infection most likely depends on tissue damage. We addressed the initial invasion process in human skin by ex vivo infection to understand how HSV-1 overcomes physical skin barriers and reaches its receptors to enter skin cells. Our results demonstrate that intact skin samples allow viral access only from the edges, while the epidermis is highly susceptible once the basal epidermal layer serves as an initial entry portal. Surprisingly, mechanical wounding did not facilitate HSV-1 entry via the skin surface, although latex beads still penetrated via the lesions. Our results imply that successful invasion of HSV-1 depends on how well the virus can reach its receptors, which was not accomplished by skin lesions under ex vivo conditions.

Pan-caspase inhibition as a potential host-directed immunotherapy against MRSA and other bacterial skin infections.

Staphylococcus aureus causes most skin infections in humans, and the emergence of methicillin-resistant S. aureus (MRSA) strains is a serious public health threat. There is an urgent clinical need for nonantibiotic immunotherapies to treat MRSA infections and prevent the spread of antibiotic resistance. Here, we investigated the pan-caspase inhibitor quinoline-valine-aspartic acid-difluorophenoxymethyl ketone (Q-VD-OPH) for efficacy against MRSA skin infection in mice. A single systemic dose of Q-VD-OPH decreased skin lesion sizes and reduced bacterial burden compared with vehicle-treated or untreated mice. Although Q-VD-OPH inhibited inflammasome-dependent apoptosis-associated speck-like protein containing caspase activation and recruitment domain (ASC) speck formation and caspase-1-mediated interleukin-1β (IL-1β) production, Q-VD-OPH maintained efficacy in mice deficient in IL-1β, ASC, caspase-1, caspase-11, or gasdermin D. Thus, Q-VD-OPH efficacy was independent of inflammasome-mediated pyroptosis. Rather, Q-VD-OPH reduced apoptosis of monocytes and neutrophils. Moreover, Q-VD-OPH enhanced necroptosis of macrophages with concomitant increases in serum TNF and TNF-producing neutrophils, monocytes/macrophages, and neutrophils in the infected skin. Consistent with this, Q-VD-OPH lacked efficacy in mice deficient in TNF (with associated reduced neutrophil influx and necroptosis), in mice deficient in TNF/IL-1R and anti-TNF antibody-treated WT mice. In vitro studies revealed that combined caspase-3, caspase-8, and caspase-9 inhibition reduced apoptosis, and combined caspase-1, caspase-8, and caspase-11 inhibition increased TNF, suggesting a mechanism for Q-VD-OPH efficacy in vivo. Last, Q-VD-OPH also had a therapeutic effect against Streptococcus pyogenes and Pseudomonas aeruginosa skin infections in mice. Collectively, pan-caspase inhibition represents a potential host-directed immunotherapy against MRSA and other bacterial skin infections.

Virulence Gene Expression of Staphylococcus aureus in Human Skin.

Staphylococcus aureus is the main cause of human skin and soft tissue infections. However, S. aureus pathogenicity within the skin is not fully characterized. Here, we implemented an S. aureus cutaneous infection model using human skin explants and performed a time-course infection to study the gene expression profile of a large panel of virulence-related factors of S. aureus USA300 LAC strain, by high-throughput RT-PCR. We pinpointed the genes that were differentially regulated by the bacteria in the skin tissues and identified 12 virulence factors that were upregulated at all time points assessed. Finally, using confocal microscopy, we show that the expression of alpha-hemolysin by S. aureus varies dependent on the skin niche and that the bacteria preferentially accumulates inside sweat glands and ducts. Taken together, our study gives insights about the pathogenic lifestyle of S. aureus within human skin tissues, which may contribute for the development of anti-S. aureus therapeutic strategies.

Case of an Exotic Skin and Soft Tissue Infection Associated with Cyclone Ockhi

Vibrio vulnificus is a halophilic marine gram-negative bacillus that is known to cause fulminant primary septicemia and complicated skin and soft tissue infections in humans. Vibrio vulnificus is referred to as flesh-eating bacteria. In the absence of timely detection and treatment, it results in sepsis with mortality of 50% and septic shock with mortality as high as 100%. Primary septicemia occurs following ingestion of contaminated seafood, and wound infections are acquired following exposure of open wounds to contaminated seawater. Early clinical suspicion and initiation of the appropriate antibiotics is essential to ensure good clinical outcome in case of Vibrio vulnificus septicemia. Here we report the case of a fisherman injured in cyclone Ockhi admitted to our hospital with lower limb cellulitis, who was diagnosed as Vibrio vulnificus wound infection. This case emphasizes the importance of history and clinical examination in antibiotic stewardship.

Evaluation of Bacterial Species in Patients with Skin Infection and their Antibiogram

Introduction: The skin is a barrier that limits invasion and growth of pathogenic bacteria. Bacterial species in patients with skin infection and their antibiogram were evaluated for the presence of inhabiting bacteria.
 Method: The sample obtained with swab sticks were streaked on their respective culture plates containing nutrient agar, MacConkey agar and blood agar, incubated 370 for 24h. The recovered bacteria after incubation were characterized and identified according to standard microbiological criteria.
 Results: Five bacteria species were isolated which includes Staphylococus aureus; Escherichia coli, Klebsiella specie, Proteus sp and Pseudomonas aeruginosa. Staphylococus aureus (33.03%) had the highest percentage occurrence while Proteus Sp (9.17%) had the lowest percentage occurrence. The highest number of isolates were recovered from male patients (61.47%). Age wise the least percentage of isolates were gotten from age group 31-40 (1.83%) while the highest was obtained from those within the age range of 11-20 (40.37%) followed by 1-10 years of age (25.69%). More isolates were recovered from in-patients (68.81%) than from Out-patients (31.19%). The antibiotic sensitivity test showed that Klebsiella sp, Proteus spp and Staphylococcus aureus were sensitivity to all the antibiotics tested while pseudomonas aeruginosa had 30% activity (sensitivity to only 3 drugs) for the antibiotics used in this study.
 Conclusion: From this study, it can be said that Staphylococcus aureus, Escherichia coli, Klebsiella sp, Proteus sp and Pseudomonas aeruginosa are implicated in the skin infections in humans and their presence if not treated will lead to long term disease in human affected.

Solanum aethiopicum: The Nutrient-Rich Vegetable Crop with Great Economic, Genetic Biodiversity and Pharmaceutical Potential

Solanum aethiopicum is a very important vegetable for both rural and urban communities in Africa. The crop is rich in both macro- and micronutrients compared with other vegetables and is suitable for ensuring food and nutritional security. It also possesses several medicinal properties and is currently employed in the treatment of high blood pressure, diabetes, cholera, uterine complaints as well as skin infections in humans. The crop is predominantly cultivated by traditional farmers and plays an important role in the subsistence and economy of poor farmers and consumers throughout the developing world. It also holds potential for dietary diversification, greater genetic biodiversity and sustainable production in Africa. Despite the numerous benefits the crop presents, it remains neglected and underutilized due to the world’s over-dependence on a few plant species, as well as the little attention in research and development it has received over the years. This review highlights the importance of S. aethiopicum, its role in crop diversification, reducing hidden hunger, the potential for nutritive and medicinal benefits, agricultural sustainability and future thrusts for breeding and genetic improvement of the plant species.

Autophagy as a Target for Drug Development Of Skin Infection Caused by Mycobacteria.

Pathogenic mycobacteria species may subvert the innate immune mechanisms and can modulate the activation of cells that cause disease in the skin. Cutaneous mycobacterial infection may present different clinical presentations and it is associated with stigma, deformity, and disability. The understanding of the immunopathogenic mechanisms related to mycobacterial infection in human skin is of pivotal importance to identify targets for new therapeutic strategies. The occurrence of reactional episodes and relapse in leprosy patients, the emergence of resistant mycobacteria strains, and the absence of effective drugs to treat mycobacterial cutaneous infection increased the interest in the development of therapies based on repurposed drugs against mycobacteria. The mechanism of action of many of these therapies evaluated is linked to the activation of autophagy. Autophagy is an evolutionary conserved lysosomal degradation pathway that has been associated with the control of the mycobacterial bacillary load. Here, we review the role of autophagy in the pathogenesis of cutaneous mycobacterial infection and discuss the perspectives of autophagy as a target for drug development and repurposing against cutaneous mycobacterial infection.

Identification of a Novel Papillomavirus Type (MfoiPV1) Associated with Acrochordon in a Stone Marten (Martes foina).

Papillomaviruses (PVs) are an extremely large group of viruses that cause skin and mucosal infections in humans and various domestic and wild animals. Nevertheless, there is limited knowledge about PVs in wildlife hosts, including mustelid species. This study describes a case in stone marten (Martes foina) with a clinical manifestation of skin tumor, which is rather atypical for infections with PVs. The result of the papillomavirus PCR performed on the skin tumor sample was positive, and the complete PV genome was determined in the studied sample using next-generation sequencing technology. The analysis of the PV genome revealed infection of the stone marten with a putative new PV type belonging to the Dyonupapillomavirus genus. The proposed new stone marten PV type was named MfoiPV1.

210 Eosinophil-derived IL-17 protects against epicutaneous Staphylococcus aureus infections

Staphylococcus aureus is the predominant cause of skin and soft tissue infections in humans and with the emergence of methicillin-resistant strains, has prompted the need for alternatives to antibiotics through a better understanding of host immune responses. IL-17-mediated immunity is crucial for host defense against S. aureus skin infections, but the immune cells involved are not entirely defined. Recently, eosinophils were identified to produce IL-17 during fungal infections. However, the role of eosinophils in IL-17-mediated immunity against S. aureus skin infections is unexplored. To investigate the role of eosinophils against S. aureus skin infections, wildtype (wt) and eosinophil-deficient mice were epicutaneously exposed to a bioluminescent strain of S. aureus and bacterial burden monitored over time. Eosinophil-deficient mice had increased bacterial burden compared to wt mice, suggesting that eosinophils contributed to host defense against S. aureus. Next, we used an IL-17A-tdTomato x IL-17F-GFP dual reporter mouse with flow cytometry to determine whether eosinophils produced IL-17A or IL-17F during S. aureus infection. Interestingly, ∼50% of IL-17A-producing cells in the S. aureus-exposed skin were eosinophils, whereas eosinophils did not produce IL-17F. To test whether eosinophil-derived IL-17 protects against S. aureus skin infections, eosinophils were adoptively transferred into IL-17A/F-deficient mice treated with neutralizing mAb against IL-17A+F or an isotype control. Indeed, eosinophils restored the host defense defect in IL-17A/F-deficient mice, but not in the presence of IL-17A+F mAbs, indicating that eosinophil-derived IL-17 promoted host defense. Taken together, we uncovered a novel mechanism whereby eosinophil-derived IL-17 protects against S. aureus skin infections, which has implications in the development of immune-based therapies against S. aureus and potentially other skin infections.

483 Antimicrobials from a feline skin commensal bacterium inhibits drug-resistant S. pseudintermedius skin colonization and infection

S. pseudintermedius is an important emerging zoonotic pathogen that can cause skin and soft tissue infections in dogs and humans. S. pseudintermedius contains virulence and antimicrobial resistance mechanisms similar to S. aureus. To combat the increasing incidence of bacterial drug resistance, the application and transplantation of commensal antimicrobial bacteria as a bacteriotherapeutic has shown clinical promise. Here we screened a selection of staphylococci isolates collected from the skin, nasal and perineum of domestic dogs and cats for antimicrobial activity against methicillin-resistant S. pseudintermedius (MRSP). We identified a S. felis C4 isolate from feline skin that inhibited growth of several important gram-positive pathogens. S. felis C4 was suitable as a bacteriotherapy, showing sensitivity to common antibiotics and was well tolerated on mouse skin. Competition experiments in mice showed that a S. felis C4 significantly reduced MRSP colonization on mouse skin (p>0.0263). Furthermore, an antimicrobial extract from S. felis C4 supernatant significantly reduced dermonecrotic skin injury during MRSP intradermal infection (p>0.0145). Through fluorescence and electron microscopy, S. felis C4 extract disrupted bacterial cell membranes but not eukaryotic cells. LC/MS identified several phenol soluble modulin beta (PSMβ1-3) peptides made by S. felis that exhibited antimicrobial activity against MRSP. RNA-Seq analysis demonstrated that the extract and PSMβ peptides also exhibited anti-inflammatory activity, suppressing TLR-mediated cytokine release from keratinocytes. Overall, these findings report antimicrobial and anti-inflammatory activity from a commensal bacterium residing on cats that could be utilized in bacteriotherapy against difficult-to-treat animal skin infections.

Designing a leucine‐rich antibacterial nonapeptide with potent activity against mupirocin‐resistant MRSA via a structure–activity relationship study

Staphylococcus aureus is the main aetiological agent responsible for the majority of human skin infections. Of particular concern is the methicillin-resistant variety, commonly known as MRSA. The extensive use of the first-line topical antibiotic of choice, mupirocin, has inevitably resulted in the emergence of resistant strains, signalling an urgent need for the development of new antibacterials with new mechanisms of action. In this work, we describe how we designed a novel cationic nonapeptide, containing only leucine and two lysine residues, with potent anti-MRSA activity and a rapid bactericidal mode of action. Coupled to a favourable safety profile towards human skin fibroblasts, we believe nonapeptide 11 has high potential for further development as a mupirocin replacement candidate to treat skin infections caused by MRSA.

Human cutaneous B cells: what do we really know?

B cells play many critical roles in the systemic immune response, including antibody secretion, antigen presentation, T cell co-stimulation, and pro- and anti-inflammatory cytokine production. However, the contribution of B cells to the local immune response in many non-lymphoid tissues, such as the skin, is incompletely understood. Cutaneous B cells are scarce except in certain malignant and inflammatory conditions, and as such, have been poorly characterized until recently. Emerging evidence now suggests an important role for cutaneous B in both skin homeostasis and pathogenesis of skin disease. Herein, we discuss the potential mechanisms for cutaneous B cell recruitment, localized antibody production, and T cell interaction in human skin infections and primary skin malignancies (i.e., melanoma, squamous cell carcinoma). We further consider the likely contribution of cutaneous B cells to the pathogenesis of inflammatory skin diseases, including pemphigus vulgaris, lupus erythematosus, systemic sclerosis, hidradenitis suppurativa, and atopic dermatitis. Finally, we examine the feasibility of B cell targeted therapy in the dermatologic setting, emphasizing areas that are still open to investigation. Through this review, we hope to highlight what we really know about cutaneous B cells in human skin, which can sometimes be lost in reviews that more broadly incorporate extensive data from animal models.

Antifungal and Antiaging Evaluation of Aerial Part Extracts ofThymelaea hirsuta(L.) Endl

In western Algeria, Thymelaea hirsuta aerial parts are traditionally used topically for the treatment of human skin infections. For a better knowledge of its biological activities, this study aimed at evaluating the in vitro antifungal activity and antiaging properties of several extracts of the aerial parts by in vitro assays. Antifungal activity was investigated by using the reference microbroth dilution method (National Committee for Clinical Laboratory Standards) against the dermatophytes ( Microsporum audouinii, Nannizzia gypsea, Trichophyton interdigitale, and Trichophyton rubrum) and the yeast ( Candida albicans). Antiaging (inhibition of 1,1-diphenyl-2-picrylhyorazyl radical scavenging and tyrosinase, lipoxygenase, elastase, and hyaluronidase activities) assays were performed in 96-well plates. All the extracts of T. hirsuta exhibited antifungal activity against M. audouinii, T. rubrum, and C. albicans, while no activity was found against N. gypsea and T. interdigitale. The highest activity was observed on M. audouinii for the aqueous leaf (minimum inhibitory concentration [MIC] of 8 µg/mL) and stem extracts (MIC = 31 µg/mL) and the methanolic leaf extract (MIC = 8 µg/mL). Additionally, some marked morphological alterations were observed on M. audouinii hyphae with all aqueous extracts. Concerning antiage bioassays, the major activity was found against hyaluronidase for the aqueous and methanolic extracts from leaves and the methanolic extract from flowers. Analysis of this last extract by high-performance liquid chromatography, electrospray ionization-mass spectrometry, and nuclear magnetic resonance, allowed us to identify daphnoretin and daphnetin as major components of this extract, and, therefore, responsible for the antiaging activity. In conclusion, this study provides additional experimental data supporting the traditional use of T. hirsuta extracts on some cutaneous dermatophytosis, as well as new perspectives on the potential use of T. hirsuta to ensure better healing of the skin.

Current trends of antibiotic resistance among human skin infections causing bacteria; a cross-sectional study

Objectives: To determine the current status of skin infections causing bacteria and their pattern of resistance to widely used antibiotics among the physician referred patients in district Peshawar, Pakistan. Materials and methods: A cross-sectional study of 164 pus samples from diseased patients, referred by physicians was done for a period from February 2020 to January 2021 at Department of Microbiology, Complex medical laboratory and Research center, Peshawar, Pakistan. Results: The bacterial growth were obtained in 88 pus samples. Among these isolated bacterial species Escherichia coli was the most prevalent pathogen, present in (46%), Staphylococcus aureus (39%), Proteus species (11%), Klebseilla species (2%) and Pseudomonas aerugenosa (2%), respectively. Among the tested antibiotics resistance wise E.coli was highly resistance to Ampicillin (92.5%), S. Aureus to Levofloxacin (91.1%), Proteus spp .to Doxycycline (90%), Klebsiella spp. to Meropenem (100%), Amoxicillin (100%) and P. aeruginosato Aztreonam (100%), Doxycycline (100%), respectively.Sensitivity wise E.coli was highly sensitive to Amikacin (90%), S. aureus to Meropenem (91.1%) and Doxycycline (91.1%),Proteus spp. to Meropenem (100%), Klebsiella spp. to Ciprofloxacin (100%), Cefotaxime (100%), Aztreonam (100%) and Doxycycline (100%), P. aeruginosa to Amikacin (100%), Meropenem(100%), Ciprofloxacin (100%), Gentamicin (100%), Cefotaxime (100%), Ceftriaxone (100%), Ampicillin (100%) and Cefotaxime (100%), respectively. Conclusion: The most prevalent skin infections causing bacteria was E.coli, followed by S. aureus, Proteus spp., Klebseilla spp. and P. aerugenosa, respectively. The antibiogram provides adequate knowledge of effective therapeutic agents for the treatment strategies of skin infections.

The latency-associated transcript locus of herpes simplex virus 1 is a virulence determinant in human skin

Herpes simplex virus 1 (HSV-1) infects skin and mucosal epithelial cells and then travels along axons to establish latency in the neurones of sensory ganglia. Although viral gene expression is restricted during latency, the latency-associated transcript (LAT) locus encodes many RNAs, including a 2 kb intron known as the hallmark of HSV-1 latency. Here, we studied HSV-1 infection and the role of the LAT locus in human skin xenografts in vivo and in cultured explants. We sequenced the genomes of our stock of HSV-1 strain 17syn+ and seven derived viruses and found nonsynonymous mutations in many viral proteins that had no impact on skin infection. In contrast, deletions in the LAT locus severely impaired HSV-1 replication and lesion formation in skin. However, skin replication was not affected by impaired intron splicing. Moreover, although the LAT locus has been implicated in regulating gene expression in neurones, we observed only small changes in transcript levels that were unrelated to the growth defect in skin, suggesting that its functions in skin may be different from those in neurones. Thus, although the LAT locus was previously thought to be dispensable for lytic infection, we show that it is a determinant of HSV-1 virulence during lytic infection of human skin.

Herpes febrilis и herpes genitalis

It is still unclear whether the causative agents of both of these diseases are identical or different. Lipschutz (Arch. F. Derm. U. Sypb., 1925, Bd. 149) indicates the difference between them on the basis of: 1) his own observations during experimental infection of human skin with a virus of both forms: 2) different duration of evolution of keratitis in a rabbit after vaccination of both viruses and 3) is different in histological skin lesions. A comparison of a number of clinical observations also indicates a difference in the etiological moment for both herpes species.

Current trends of antifungal susceptibility pattern of dermatomycosis in a tertiary care hospital by Etest and VITEK-2 methodologies

Dermatomycosis affect the superficial layers of the skin, nails and hair and are often caused by dermatophytic molds, candida & non dermatophytic molds. However, over the last decade, an increasing number of non– dermatophyte filamentous fungi & non albicans Candida have been recognized as agents of skin and nail infections in humans, producing lesions clinically similar to those caused by dermatophytes. Although tissue invasion by them is a rare possibility, they are important as a public health problem particularly in the immunocompromised. There are limited studies on the efficacy of antifungal agents against dermatophytes. This study was conducted to test the efficacy of 3 systemic antifungal agents viz. Voriconazole, Itraconazole & Fluconazole using the E-test method and 2 systemic antifungals viz. Itraconazole and Voriconazole by VITEK-2. Three different species of dermatophytes which were isolated from the clinically suspected cases were Trichophyton mentagrophytes, T.rubrum and M.gypseum. According to the obtained results, Itraconazole and Voriconazole showed the lowest MIC range while Fluconazole had the highest MIC range for most fungi tested. Determining the resistance pattern is especially necessary to assist clinicians in treating superficial fungal infections more effectively. This will minimize side effects and prevent development of antifungal resistance & treatment failures. Keywords: Dermatomycosis, Antifungal resistance, Etest, VITEK-2, Voriconazole, Itraconazole, Fluconazole.

Genotyping of Russian isolates of fungal pathogen Trichophyton rubrum, based on simple sequence repeat and single nucleotide polymorphism.

The Trichophyton rubrum species group consists of prevalent causative agents of human skin, nail and hair infections, including Trubrum sensu stricto and Tviolaceum, as well as other less well-established or debatable taxa like Tsoudanense, Tkuryangei and Tmegninii. Our previous study provided limited evidence in favour of the existence of two genetic lineages in the Russian Trubrum sensu stricto population. We aimed to study the genetic structure of the Russian population of Trubrum and to identify factors shaping this structure. We analysed the polymorphism of 12 simple sequence repeat (SSR or microsatellite) markers and single nucleotide polymorphism in the TERG_02941 protein-coding gene in 70 Trubrum isolates and performed a phylogenomic reconstruction. All three types of data provided conclusive evidence that the population consists of two genetic lineages. Clustering, performed by means of microsatellite length polymorphism analysis, was strongly dependent on the number of nucleotide repeats in the 5'-area of the fructose-1,6-bisphosphate aldolase gene. Analysis of molecular variance (AMOVA) on the basis of SSR typing data indicated that 22%-48% of the variability was among groups within Trubrum. There was no clear connection of population structure with types of infection, places of geographic origin, aldolase gene expression or urease activity. Our results suggest that the Russian population of Trubrum consists of two cosmopolitan genetic lineages.