Application of MALDI-TOF mass spectrometry for identification of Nocardia species.

BACKGROUND: Nocardiosis, despite its rarity and underreporting, is significant due to its severe impact, characterized by high morbidity and mortality rates. The development of a precise, reliable, rapid, and straightforward technique for identifying the pathogenic agent in clinical specimens is crucial to reduce fatality rates and facilitate timely antimicrobial treatment. In this study, we aimed to identify Nocardia spp. in clinical isolates, using MALDI-TOF MS as the primary method, with molecular methods as the gold standard. Clinical Nocardia isolates were identified using 16S rRNA/hsp65/gyrB/secA1/rpoB gene sequencing. Identification performance of the Bruker MALDI Biotyper 3.1 (V09.0.0.0_8468) and MBT Compass 4.1 (V11.0.0.0_10833) for Nocardia identification was evaluated. RESULTS: Seventy-six Nocardia isolates were classified into 12 species through gene sequencing. The MALDI Biotyper 3.1 (V09.0.0.0_8468) achieved 100% genus-level accuracy and 84.2% species accuracy (64/76). The MBT Compass 4.1 with the BDAL Database (V11.0.0.0_10833) improved species identification to 98.7% (75/76). The updated database enhanced species level identification with scores > 1.7, increasing from 77.6% (59/76) to 94.7% (72/76), a significant improvement (P = 0.001). The new and simplified extraction increased the proportion of strains identified to the species level with scores > 1.7 from 62.0% (18/29) to 86.2% (25/29) (P = 0.016). An in-house library construction ensured accurate species identification for all isolates. CONCLUSIONS: The Bruker mass spectrometer can accurately identify Nocardia species, albeit with some variations observed between different database versions. The MALDI Biotyper 3.1 (V09.0.0.0_8468) has limitations in identifying Nocardia brasiliensis, with some strains only identifiable to the genus level. MBT Compass 4.1 (V11.0.0.0_10833) effectively addresses this shortfall, improving species identification accuracy to 98.7%, and offering quick and reliable identification of Nocardia. Both database versions incorrectly identified the clinically less common Nocardia sputorum as Nocardia araoensis. For laboratories that have not upgraded their databases and are unable to achieve satisfactory identification results for Nocardia, employing the new and simplified extraction method can provide a degree of improvement in identification outcomes.

Bacteria-responsive functional electrospun membrane: simultaneous on-site visual monitoring and inhibition of bacterial infection.

Skin infections are a major threat to human health. Early diagnosis of bacterial infections is of great significance for implementing protective measures on the skin. Therefore, in this study, we designed an electrospun membrane (PPBT) for visual monitoring of colonized bacteria and responsive antibacterial ability. Specifically, the acidity of the microenvironment caused by bacterial metabolism was applied to drive the color change of bromothymol blue (BTB) on the PPBT membrane from green to yellow, thereby facilitating the early warning of infection and timely treatment. Within 4 h, different concentrations of Staphylococcus aureus (∼105 CFU mL-1), Escherichia coli (∼105 CFU mL-1), Pseudomonas aeruginosa (∼105 CFU mL-1) and Candida albicans (∼104 CFU mL-1) were visually monitored. Moreover, as the local acidity was enhanced via microbial metabolism, ZIF-8 nanoparticles loaded with TCS (TCS@ZIF-8) on the PPBT membrane could release TCS in an acid-responsive manner. At the same time, ROS were generated under 405 nm irradiation to achieve synergistic antibacterial ability. Experiments confirmed that the PPBT membrane has ideal and controllable antibacterial features based on acid responsive release and a synergistic photocatalytic antibacterial mechanism after monitoring. Therefore, the PPBT membrane developed in this work provides a feasible solution for bacterial monitoring and inactivation devices. More importantly, it can be beneficial for meeting the needs of clinical diagnosis and timely treatment of bacterial infection.

Photocuring and Gelatin-Based Antibacterial Hydrogel for Skin Care.

The development of moisturizing, antibacterial, and biocompatible multifunctional hydrogels is essential to protect skin and promote skin defects recovery. Gelatin has admired potential to be applied for skin care as a hydrogel in virtue of its hydrophilic biocompatible and biodegradable properties. In this study, triclosan-grafted gelatin and photo-cross-linkable methacrylated gelatin were synthesized and then combined to construct the semi-interpenetrating network and antibacterial hydrogels with the aid of a visible blue light. The antimicrobial test demonstrated that the resulting hydrogel obtained excellent inactivation capacity against E. coli, S. aureus, T. rubrum, and C. albicans with sterilizing rates of 99.998%, 99.998%, 99.19%, and 99.64%, respectively. In addition, the cytotoxicity, hemolysis, skin irritation, and rat skin wound healing experiments proved the good biocompatibility of the hydrogel. Therefore, this investigation sheds light on the development of multifunctional hydrogels in skin care.

Acute generalized exanthematous pustulosis complicated by cutaneous small vessel vasculitis: A case report and literature review.

Acute generalized exanthematous pustulosis (AGEP) is a rare skin eruption characterized by widespread erythematous lesions covered with numerous pustules. Leukocytoclastic vasculitis is now considered an uncommon but possible histopathological feature within the clinical and pathological spectrum of AGEP. Our report describes a rare case of AGEP overlapping with cutaneous small vessel vasculitis, a condition that has only been reported once in the literature.

Oral treatment with 10% potassium iodide solution for refractory cutaneous-disseminated sporotrichosis in an immunocompetent adult: Case report.

Sporotrichosis has multiple clinical manifestations, and its cutaneous-disseminated form is uncommon and, in most cases, related to immunosuppressive conditions. We report the case of a 47-year-old male patient who presented with multiple cutaneous nodules and ulcers on the left upper limb and the right thigh, with no other comorbidities. Until the diagnosis was confirmed, the patient was initially given empiric antifungal treatment with itraconazole, which showed unsatisfactory results at a local hospital. Then, he was treated with voriconazole, which led to the slow improvement of his skin lesions. At one point during the voriconazole treatment course, the patient briefly self-discontinued voriconazole for economic reasons, and the lesions recurred and worsened. The patient was finally diagnosed with cutaneous-disseminated sporotrichosis based on the isolation and identification of Sporothrix globosa. Susceptibility testing revealed that the isolate was resistant to itraconazole, fluconazole, voriconazole, terbinafine, and amphotericin. Considering the patient's poor financial condition, potassium iodide was administered. After 1-month of therapy with potassium iodide, he reported rapid improvement of his skin lesions. The patient continued potassium iodide treatment for another 5 months until the full resolution of lesions was achieved.

Cage-modified hypocrellin against multidrug-resistant Candida spp. with unprecedented activity in light-triggered combinational photodynamic therapy.

Infections caused by multidrug-resistant fungi pose a devastating threat to human health worldwide, making new antifungal strategies urgently desired. Antimicrobial photodynamic therapy (aPDT) has gained increasing attention due to its potential in fighting against fungal infection. However, the preparation of highly efficient and water-soluble photosensitizers (PSs) for this purpose remains a challenge. Herein, we present a new strategy to prepare powerful PSs for efficient aPDT by introducing a porous cage compound, which could facilitate the transportation of O2 and reactive oxygen species (ROS). Specifically, the natural PS hypocrellin A (HA) was attached to a novel organic cage compound (covalent organic polyhedra 1 tied, COP1T) with polyethylene glycol (PEG) chains to improve its water solubility. It was found that the resulting COP1T-HA exhibited in vitro antifungal efficiency several folds higher compared to the free HA in fighting against four types of multidrug-resistant fungal planktonic cells and biofilms, including the "super fungus" Candida auris. Interestingly, the red-shift of COP1T-HA adsorption led to the realization of phototheranostic aPDT for cage-modified HA or derivatives. Additionally, COP1T-HA exhibited good biocompatibility, excellent disinfection capacity and wound healing efficiency without obvious toxic effects in vivo of rat model. With further development and optimization, COP1T-HA has great potential to become a new class of antifungal agent to fight against drug-resistant pathogens.

A recyclable and light-triggered nanofibrous membrane against the emerging fungal pathogen Candida auris.

The emerging "super fungus" Candida auris has become an important threat to human health due to its pandrug resistance and high lethality. Therefore, the development of novel antimicrobial strategy is essential. Antimicrobial photodynamic therapy (aPDT) has excellent performance in clinical applications. However, the relevant study on antifungal activity and the mechanism involved against C. auris remains scarce. Herein, a recyclable and biodegradable polylactic acid-hypocrellin A (PLA-HA) nanofibrous membrane is newly developed. In vitro PLA-HA-aPDT could significantly reduce the survival rate of C. auris plankton and its biofilms, and the fungicidal effect of the membrane is still significant after four repeated uses. Simultaneously, PLA-HA exhibits good biocompatibility and low hemolysis. In vivo experiments show that PLA-HA-aPDT can promote C. auris-infected wound healing, reduce inflammatory response, and without obvious toxic side-effects. Further results reveal that PLA-HA-aPDT could increase endogenous reactive oxygen species (ROS) levels, leading to mitochondrial dysfunction, release of cytochrome C, activation of metacaspase, and nuclear fragmentation, thereby triggering apoptosis of C. auris. Compared with HA, PLA-HA shows stronger controllability and reusability, which can greatly improve the utilization efficiency of HA alone. Taken together, the efficacy, safety and antifungal activity make PLA-HA-aPDT a highly promising antifungal candidate for skin or mucous membrane C. auris infection.

Skin Microbiota in Non-inflammatory and Inflammatory Lesions of Acne Vulgaris: The Underlying Changes within the Pilosebaceous Unit.

Acne vulgaris is a common chronic inflammatory skin disease of the pilosebaceous unit. Clinical manifestations include seborrhea, non-inflammatory lesions, inflammatory lesions, or scar formation. Fourteen eligible participants of either sex, aged 18-28 years old, with mild to moderate acne lesions, were recruited in this observational study. The contents of 10 pilosebaceous units of non-inflammatory (comedones) and inflammatory lesions (papules and pustules) were collected from each participant's face and examined by amplicon metagenomics sequencing and real-time Polymerase Chain Reaction (PCR). Male participants, participants with a higher body mass index (BMI) than normal, and participants younger than 20 years old, were revealed to have a higher proportion of Malassezia in their non-inflammatory lesions than that in inflammatory lesions. There was an increased abundance of Malassezia restricta (M. restricta) and Cutibacterium acnes (C. acnes) in the non-inflammatory group. Correlation analysis indicated that Staphylococcus epidermidis (S. epidermidis) and M. restricta have similar proliferation trends with C. acnes during the transformation from non-inflammatory to inflammatory lesions. M. restricta probably involve in the microecological balance within the pilosebaceous unit.

Nocardia huaxiensis sp. nov., an actinomycete isolated from human skin.

A novel actinomycete, designated as strain WCH-YHL-001T, was isolated from skin biopsy specimens of a patient at West China Hospital, Chengdu, Sichuan Province, PR China. The cells were Gram-positive, aerobic, heterotrophic and non-motile. They formed an extensive substrate with short aerial mycelia, whose branches fragmented into rod-shaped elements. Growth occurred at 10-40 °C, pH 5.0-12.0 and with NaCl concentrations of 0-4.0 % (w/v). The major cellular fatty acids of strain WCH-YHL-001T were C16 : 0, C18 : 1 ω9c, C18 : 0 10-methyl and summed feature 3. The predominant respiratory quinone was MK-8 (H4ω-cycl). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannoside, unknown phospholipids and unidentified glycolipids. The diagnostic diamino acid of peptidoglycan was meso-diaminopimelic acid. The whole-cell sugar pattern consisted of arabinose and glucose. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain WCH-YHL-001T belonged to the genus Nocardia. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between strain WCH-YHL-001T and type strains of Nocardia species were lower than the cut-offs (≥95-96 % for ANI and ≥70 % for isDDH) required to define a bacterial species. The genomic DNA G+C content was 67.8 mol%. Phylogenetic, physiological and chemotaxonomic data suggested that strain WCH-YHL-001T represented a novel species of the genus Nocardia, for which the name Nocardia huaxiensis sp. nov. is proposed, with the type strain WCH-YHL-001T (=GDMCC 4.181T=JCM 34475 T=NBRC 114973T).

Itraconazole Induces Regression of Infantile Hemangioma via Downregulation of the Platelet-Derived Growth Factor-D/PI3K/Akt/mTOR Pathway.

Infantile hemangioma is the most common benign vascular tumor of infancy. We have previously reported that itraconazole, a common antifungal agent, can clinically improve or cure infantile hemangioma; however, the underlying molecular mechanisms are still unclear. Here, we show that itraconazole treatment significantly inhibits proliferation and promotes apoptosis of the endothelial cells of mouse hemangioma cell line and infantile primary hemangioma endothelial cell. Itraconazole also remarkably reduced angiogenesis of hemangioma endothelial cell in vitro. We further performed transcriptome profiling via mRNA microarrays in hemangioma endothelial cell upon itraconazole treatment, and identified cytokine-cytokine receptor interaction as the top significantly enriched pathway. Importantly, itraconazole significantly reduced platelet-derived growth factor-D level, resulting in suppression of platelet-derived growth factor-ß activation and inhibition of its downstream effectors, such as PI3K, Akt, 4E-BP1, and p70S6K, which are important for cellular growth and survival of infantile hemangioma. In conclusion, our results suggest that platelet-derived growth factor-D is a target of itraconazole in infantile hemangioma.

An Unusual Case of White Piedra Due to Trichosporon inkin Mimicking Trichobacteriosis.

White piedra is a superficial mycosis characterized by soft, white-to-tan, irregular nodules attached to the hair shafts. A 36-year-old man presented with small lumps in his pubic hair, without any other symptoms. The clinical features were suggestive of trichobacteriosis. Pathology analysis of the infected hair revealed that the concretions surrounding the hair shaft were full of fungal elements, parts of which had invaded into the cuticle. Culture on Sabouraud dextrose agar grew creamy, yellow-white colonies identified as Trichosporon inkin by the sequence of the nuclear ribosomal intergenic spacer region. The condition was treated by shaving the pubic hair and administering antifungal therapy (oral itraconazole and topical ketoconazole).

Oral treatment with valacyclovir for HSV-2-associated eczema herpeticum in a 9-month-old infant: A case report.

BACKGROUND: Eczema herpeticum is a rare, severe, and disseminated infection of herpes simplex virus in the setting of eczematous skin diseases. METHODS: We experienced a case of this disease in a 9-month-old infant characterized by a sudden onset of monomorphic vesicles on the head, right lower leg, and two hands. The infant has a 7-month history of atopic dermatitis and his condition was initially regarded as a complication of atopic dermatitis and bacterial infection. After treatment of cefoperazone and dexamethasone, the eruptions got worse. The diagnosis of eczema herpeticum was made according to the clinical features and further confirmed by the findings of herpes simplex virus type 2. RESULTS: The infant was cured by oral treatment with valacyclovir. CONCLUSION: The case highlights that the awareness for the sign of eczema herpeticum when diagnosing children with a sudden onset of disseminated vesicles in the setting of chronic skin disease should be increased. Oral valacyclovir may be an effective and convenient treatment option for pediatric outpatients with eczema herpeticum.

An ultrastructural study on corkscrew hairs and cigarette-ash-shaped hairs observed by dermoscopy of tinea capitis.

This study was aimed to explain the formation mechanisms of corkscrew hairs and cigarette-ash-shaped hairs observed by dermoscopy of tinea capitis. In the present work, the ultrastructure of the involved hairs collected from a girl with tinea capitis caused by Trichophyton violaceum was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). SEM observation of the corkscrew hair revealed bent hair shaft and asymmetrically disrupted cuticle layer. TEM findings demonstrated the hair shaft became weak. The corkscrew hairs closely covered by scales on the scalp were observed under dermoscopy. We speculate that the formation of corkscrew hairs is a result of a combination of internal damage due to hair degradation by T. violaceum and external resistance due to scales covering the hair. SEM observation of the cigarette-ash-shaped hair revealed irregularly disrupted and incompact end, which might represent the stump of the broken corkscrew hair after treatment.