Single-Dose Rifapentine in Household Contacts of Patients with Leprosy.

BACKGROUND: Previous studies have suggested that a single dose of rifampin has protective effects against leprosy in close contacts of patients with the disease. Rifapentine was shown to have greater bactericidal activity against Mycobacterium leprae than rifampin in murine models of leprosy, but data regarding its effectiveness in preventing leprosy are lacking. METHODS: We conducted a cluster-randomized, controlled trial to investigate whether single-dose rifapentine is effective in preventing leprosy in household contacts of patients with leprosy. The clusters (counties or districts in Southwest China) were assigned to one of three trial groups: single-dose rifapentine, single-dose rifampin, or control (no intervention). The primary outcome was the 4-year cumulative incidence of leprosy among household contacts. RESULTS: A total of 207 clusters comprising 7450 household contacts underwent randomization; 68 clusters (2331 household contacts) were assigned to the rifapentine group, 71 (2760) to the rifampin group, and 68 (2359) to the control group. A total of 24 new cases of leprosy occurred over the 4-year follow-up, for a cumulative incidence of 0.09% (95% confidence interval [CI], 0.02 to 0.34) with rifapentine (2 cases), 0.33% (95% CI, 0.17 to 0.63) with rifampin (9 cases), and 0.55% (95% CI, 0.32 to 0.95) with no intervention (13 cases). In an intention-to-treat analysis, the cumulative incidence in the rifapentine group was 84% lower than that in the control group (cumulative incidence ratio, 0.16; multiplicity-adjusted 95% CI, 0.03 to 0.87; P = 0.02); the cumulative incidence did not differ significantly between the rifampin group and the control group (cumulative incidence ratio, 0.59; multiplicity-adjusted 95% CI, 0.22 to 1.57; P = 0.23). In a per-protocol analysis, the cumulative incidence was 0.05% with rifapentine, 0.19% with rifampin, and 0.63% with no intervention. No severe adverse events were observed. CONCLUSIONS: The incidence of leprosy among household contacts over 4 years was lower with single-dose rifapentine than with no intervention. (Funded by the Ministry of Health of China and the Chinese Academy of Medical Sciences; Chinese Clinical Trial Registry number, ChiCTR-IPR-15007075.).

Spatiotemporal pattern of leprosy in southwest China from 2010 to 2020: an ecological study.

BACKGROUND: Despite many efforts to control leprosy worldwide, it is still a significant public health problem in low- and middle-income regions. It has been endemic in China for thousands of years, and southwest China has the highest leprosy burden in the country. METHODS: This observational study was conducted with all newly detected leprosy cases in southwest China from 2010 to 2020. Data were extracted from the Leprosy Management Information System (LEPMIS) database in China. The Joinpoint model was used to determine the time trends in the study area. Spatial autocorrelation statistics was performed to understand spatial distribution of leprosy cases. Spatial scan statistics was applied to identify significant clusters with high rate. RESULTS: A total of 4801 newly detected leprosy cases were reported in southwest China over 11 years. The temporal trends declined stably. The new case detection rate (NCDR) dropped from 4.38/1,000,000 population in 2010 to 1.25/1,000,000 population in 2020, with an average decrease of 12.24% (95% CI: -14.0 to - 10.5; P < 0.001). Results of global spatial autocorrelation showed that leprosy cases presented clustering distribution in the study area. Most likely clusters were identified during the study period and were frequently located at Yunnan or the border areas between Yunnan and Guizhou Provinces. Secondary clusters were always located in the western counties, the border areas between Yunnan and Sichuan Provinces. CONCLUSIONS: Geographic regions characterized by clusters with high rates were considered as leprosy high-risk areas. The findings of this study could be used to design leprosy control measures and provide indications to strengthen the surveillance of high-risk areas. These areas should be prioritized in the allocation of resources.

Granulysin-mediated reduction of PDZRN3 induces Cx43 gap junctions activity exacerbating skin damage in trichloroethylene hypersensitivity syndrome.

Trichloroethylene (TCE)-induced hypersensitivity syndrome (THS) has been a concern for many researchers in the field of environmental and occupational health. Currently, there is no specific treatment for THS, leaving patients to contend with severe infections arising from extensive skin lesions, consequently leading to serious adverse effects. However, the pathogenesis of severe skin damage in THS remains unclear. This study aims to investigate the specific danger signals and mechanisms underlying skin damage in THS through in vivo and in vitro experiments. We identified that cell supernatant containing 15 kDa granulysin (GNLY), released from activated CD3-CD56+NK cells or CD3+CD56+NKT cells in PBMC induced by TCE or its metabolite, promoted apoptosis in HaCaT cells. The apoptosis level decreased upon neutralization of GNLY in the supernatant by a GNLY-neutralizing antibody in HaCaT cells. Subcutaneous injection of recombinant 15 kDa GNLY exacerbated skin damage in the THS mouse model and better mimicked patients' disease states. Recombinant 15 kDa GNLY could directly induce cellular communication disorders, inflammation, and apoptosis in HaCaT cells. In addition to its cytotoxic effects, GNLY released from TCE-activated NK cells and NKT cells or synthesized GNLY alone could induce aberrant expression of the E3 ubiquitin ligase PDZRN3, causing dysregulation of the ubiquitination of the cell itself. Consequently, this resulted in the persistent opening of gap junctions composed of connexin43, thereby intensifying cellular inflammation and apoptosis through the "bystander effect". This study provides experimental evidence elucidating the mechanisms of THS skin damage and offers a novel theoretical foundation for the development of effective therapies targeting severe dermatitis induced by chemicals or drugs.

Overview and Current Advances in Dapsone Hypersensitivity Syndrome.

PURPOSE OF REVIEW: As a sulfone antibacterial agent, dapsone has been widely used to treat leprosy. Moreover, dapsone is also used in many immune diseases such as herpetic dermatitis because of its anti-inflammatory and immunomodulatory effects. However, dapsone can cause several adverse effects, the most serious being dapsone hypersensitivity syndrome. Dapsone hypersensitivity syndrome is characterized by a triad of eruptions, fever, and organ involvement, which limits the application of dapsone to some extent. RECENT FINDINGS: In this article, we review current research about the interaction model between HLA-B*13:01, dapsone, and specific TCR in dapsone-induced drug hypersensitivity. In addition to the proposed mechanisms, we also discussed clinical features, treatment progress, prevalence, and prevention of dapsone hypersensitivity syndrome. These studies reveal the pathogenesis, clinical features, and prevalence from the perspectives of genetic susceptibility and innate and adaptive immunity in dapsone hypersensitivity syndrome, thereby guiding clinicians on how to diagnose, prevent, and treat dapsone hypersensitivity syndrome.

Research on the descaling characteristics of a new electrochemical water treatment device.

In recent years, chemical water treatment equipment has gained significant attention due to its environmental-friendly features, multifunctionality, and broad applicability. Recognizing the limitations of existing chemical treatment equipment, such as challenges in scale removal and the high water content in scale deposits, we propose a novel drum design for both anode and cathode, enabling simultaneous scale suction and dehydration. We constructed a small experimental platform to validate the equipment's performance based on our model. Notably, under the optimal operating parameters, the hardness removal rate for circulating water falls within the range of 19.6-24.46%. Moreover, the scale accumulation rate per unit area and unit time reaches 13.7 g h-1 m-2. Additionally, the energy consumption per unit weight of the scale remains impressively low at 0.16 kWh g-1. Furthermore, the chemical oxygen demand (COD) concentration decreased from an initial 106.0 mg L-1 to a mere 18.8 mg L-1, resulting in a remarkable total removal rate of 82.26%. In conclusion, our innovative electrochemical water treatment equipment demonstrates exceptional performance in scale removal, organic matter degradation, and water resource conservation, offering valuable insights for future research and development in chemical treatment equipment and electrochemical theory.

Functional and structural characteristics of HLA-B*13:01-mediated specific T cells reaction in dapsone-induced drug hypersensitivity.

BACKGROUND: Severe cutaneous adverse drug reactions (SCARs) are a group of serious clinical conditions caused by immune reaction to certain drugs. The allelic variance of human leukocyte antigens of HLA-B*13:01 has been strongly associated with hypersensitivities induced by dapsone (DDS). T-cell receptor mediated activation of cytotoxic T lymphocytes (CTLs) has also been suggested to play an essential role in pathogenesis of SCARs. However, HLA-B*13:01-DDS-TCR immune synapse that plays role in drug-induced hypersensitivity syndrome (DIHS) associated T cells activation remains uncharacterized. METHODS: To investigate the molecular mechanisms for HLA-B*13:01 in the pathogenesis of Dapsone-induced drug hypersensitivity (DDS-DIHS), we performed crystallization and expanded drug-specific CTLs to analyze the pathological role of DDS-DIHS. RESULTS: Results showed the crystal structure of HLA-B*13:01-beta-2-microglobulin (ß2M) complex at 1.5 Å resolution and performed mutation assays demonstrating that I118 or I119, and R121 of HLA-B*13:01 were the key residues that mediate the binding of DDS. Subsequent single-cell TCR and RNA sequencing indicated that TCRs composed of paired TRAV12-3/TRBV28 clonotype with shared CDR3 region specifically recognize HLA-B*13:01-DDS complex to trigger inflammatory cytokines associated with DDS-DIHS. CONCLUSION: Our study identified the novel p-i-HLA/TCR as the model of interaction between HLA-B*13:01, DDS and the clonotype-specific TCR in DDS-DIHS.

Isolation of Novel Mycobacterium Species from Skin Infection in an Immunocompromised Person.

We investigated a case of cutaneous infection in an immunocompromised patient in China that was caused by a novel species within the Mycobacterium gordonae complex. Results of whole-genome sequencing indicated that some strains considered to be M. gordonae complex are actually polyphyletic and should be designated as closely related species.

Intact Mycobacterium leprae Isolated from Placenta of a Pregnant Woman, China.

Whether Mycobacterium leprae transmits from placenta to fetus remains unknown. We describe the case of a pregnant woman with untreated histoid leproma. Although her newborn was healthy, laboratory examination revealed intact M. leprae present in the placenta, suggesting that the placental barrier might prevent vertical dissemination of M. leprae.

Cutaneous Tuberculosis and Nontuberculous Mycobacterial Infections at a National Specialized Hospital in China.

To identify the microorganism distribution clinical characteristics and management of cutaneous Mycobacterium tuberculosis and nontuberculous mycobacterial infectious diseases in the past 10 years we collected and analyzed the patient records of all cutaneous M. tuberculosis and nontuberculous mycobacterial infection cases diagnosed by culture and/or PCR from 2008 to 2017 in the Hospital of Dermatology Chinese Academy of Medical Sciences. Among 203 cases including 89 M. tuberculosis infections and 114 nontuberculous mycobacterial infections M. tuberculosis was the most common species in all patients and M. marinum predominated among the nontuberculous mycobacterial followed by M. abscessus. Cases of cutaneous mycobacterial infection especially nontuberculous mycobacterial infection increased in the past 10 years and infection with rapidly growing mycobacteria significantly increased in the last 5 years in this national hospital in Southeast China. Injuries were common causative factors. Approximately 91.3% of patients responded well to longstanding antibiotic therapy.

Mycobacterium gordonae in Patient with Facial Ulcers, Nosebleeds, and Positive T-SPOT.TB Test, China.

Mycobacterium gordonae is often regarded as a weak pathogen that only occasionally causes overt disease. We report a case of M. gordonae infection in the facial skin, nasal mucosa, and paranasal sinus in an immunocompetent patient and review previous cases. The T-SPOT.TB test might be useful in diagnosing such cases.

Molecular Characteristics of Mycobacterium tuberculosis Strains Isolated from Cutaneous Tuberculosis Patients in China.

Cutaneous tuberculosis (CTB) is probably underreported due to difficulties in detection and diagnosis. To address this issue, genotypes of Mycobacterium tuberculosis strains isolated from 30 patients with CTB were mapped at multiple loci, namely, RD105 deletions, spacer oligonucleotides, and Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats (MIRU-VNTRs). Fifty-eight strains of pulmonary tuberculosis (PTB) were mapped as experimental controls. Drug resistance-associated gene mutations were determined by amplicon sequencing of target regions within 7 genes. Beijing family isolates were the most prevalent strains in CTB and PTB. MIRU-VNTR typing separated the Beijing strains from the non-Beijing strains, and the majority of CTB could be separated from PTB counterparts. Drug resistance determining regions showed only one CTB strain expressing isomazid resistance. Thus, while the CTB strains belonged to the same phylogenetic lineages and sub-lineages as the PTB strains, they differed at the level of several MIRU-VNTRs and in the proportion of drug resistance.

Isolation and characterization of a non-specific endoglucanase from a metagenomic library of goat rumen.

A cellulase gene (cel28a) was isolated from a rumen microbial metagenome library of goat rumen microorganisms, cloned into E. coli, and expressed in active form. The gene has a length of 1596 bp obtained using a genome walking Kit and encodes a protein of 509 amino acids with a calculated MW of 55 kDa. The deduced amino acid sequence was homologous with cellulases belonging to the glycosyl hydrolase family 5 (GH5). The expressed protein showed activity toward carboxymethylcellulose (CMC) and xylan, suggesting non-specific endoglucanase activity. The optimal conditions for endoglucanase and xylanase activities were 50 °C and pH 5.0. The metal ions (Ca(2+), Fe(2+), Mn(2+) and Co(2+)) stimulated the cellulase activity of cel28a, while the other metal ions and chemicals (Ni(2+), Mg(2+), Zn(2+), Cu(2+), SDS and EDTA) inhibited the cellulase activity. Further examination of substrate preference showed a higher activity with CMC, oat spelt xylan and birchwood xylan than with filter paper and microcrystalline cellulose, again suggesting that the protein was an endoglucanase with xylanase activity.

Cutaneous infections caused by rapidly growing mycobacteria: case reports and review of clinical and laboratory aspects.

Skin and soft tissue infections caused by rapidly growing non-tuberculous mycobacteria (RG-NTM) have become a growing clinical concern over the past decades. These RG-NTM are ubiquitous environmental organisms and most are resistant to traditional antituberculous agents. In this report, we describe 3 cutaneous infections caused by RG-NTM, namely, Mycobacterium abscessus, M. chelonae, and M. conceptionense, and present the clinical and laboratory characteristics of these infections.

Human Adipose-Derived Mesenchymal Stem Cells Colonize and Promote Healing of Leprosy Ulcer by Inducing Neuro-Vascularization.

Leprosy ulcer is a chronic and recurrent disease resulting from nerve injury. While existing treatments partially facilitate ulcer healing, they exhibit limited ability to address localized nerve repair, leading to a risk of recurrence. Moreover, there is a dearth of animal models to evaluate the preclinical efficacy and safety of novel therapeutic approaches. Over the years, adipose-derived mesenchymal stem cells have been extensively employed in regenerative medicine as an optimal cell therapy source for fostering skin ulcer healing. They have also demonstrated the capacity to enhance nerve regeneration in in vitro experiments and clinical trials. In this study, we established a NU/NU mouse foot pad leprosy ulcer model, transplanted human adipose-derived stem cells (hADSCs) into leprosy ulcers via local injection, and conducted subsequent follow-up. Our findings revealed that hADSCs persisted in the leprosy ulcer and facilitated the healing process. In this respect, gross observation and histological analysis revealed increased granular formation, collagen synthesis, and re-epithelialization in the local ulcer area. RNA-Seq data revealed that the upregulated differential genes resulting from the transplantation intervention were not only enriched in pathways related to re-epithelialization and collagen synthesis but also contributed to local nerve regeneration. Furthermore, immunofluorescence assays revealed the increased expression of angiogenesis markers-CD31 and VEGFa, cell proliferation markers-Ki67 and TGF-ß, and nerve regeneration markers-ß3-tubulin, SOX10, NGF, and NT-3. These results underscore the potential of hADSCs in promoting the healing of leprosy ulcers and offer valuable preclinical data for their prospective clinical application.

Unveiling the mechanisms of trichloroethylene hypersensitivity syndrome: Exploring the role of connexin 43 gap junctions in severe skin damage.

Trichloroethylene (TCE), extensively used as an organic solvent in various industrial applications, has been identified as a causative factor in inducing hypersensitivity syndrome (THS). Currently, there is no specific treatment for THS, and most patients experience serious adverse outcomes due to extensive skin damage leading to severe infection. However, the pathogenesis of THS-associated skin damage remains unclear. This study aims to elucidate the mechanism underlying skin damage from the perspective of intercellular communication and gap junctions in THS. Our results verified that hyperactivation of connexin43 gap junctions, caused by the aberrantly elevated expression of connexin43, triggers a bystander effect that promotes apoptosis and inflammation in THS via the TNF-TNFRSF1B and mitochondria-associated pathways. Additionally, we identified the gap junction inhibitor Carbenoxolone disodium (CBX) as a promising agent for the treatment of skin damage in THS. CBX protects against inflammatory cell infiltration in the skin and decreases immune cell imbalance in the peripheral blood of THS mice. Furthermore, CBX reduces connexin43 expression, apoptosis and inflammation in THS mice. The study reveals new insights into the mechanisms underlying TCE-induced skin damage, offering a potential treatment strategy for the development of effective therapies targeting severe dermatitis induced by chemical exposure.

Molecular epidemiological characteristics of Mycobacterium leprae in highly endemic areas of China during the COVID-19 epidemic.

Objectives: The present study analyzed the impact of the COVID-19 pandemic on the prevalence and incidence of new leprosy cases, as well as the diversity, distribution, and temporal transmission of Mycobacterium leprae strains at the county level in leprae-endemic provinces in Southwest China. Methods: A total of 219 new leprosy cases during two periods, 2018-2019 and 2020-2021, were compared. We genetically characterized 83 clinical isolates of M. leprae in Guizhou using variable number tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). The obtained genetic profiles and cluster consequences of M. leprae were compared between the two periods. Results: There was an 18.97% decrease in the number of counties and districts reporting cases. Considering the initial months (January-March) of virus emergence, the number of new cases in 2021 increased by 167% compared to 2020. The number of patients with a delay of >12 months before COVID-19 (63.56%) was significantly higher than that during COVID-19 (48.51%). Eighty-one clinical isolates (97.60%) were positive for all 17 VNTR types, whereas two (2.40%) clinical isolates were positive for 16 VNTR types. The (GTA)9, (TA)18, (TTC)21 and (TA)10 loci showed higher polymorphism than the other loci. The VNTR profile of these clinical isolates generated five clusters, among which the counties where the patients were located were adjacent or relatively close to each other. SNP typing revealed that all clinical isolates possessed the single SNP3K. Conclusion: COVID-19 may have a negative/imbalanced impact on the prevention and control measures of leprosy, which could be a considerable fact for official health departments. Isolates formed clusters among counties in Guizhou, indicating that the transmission chain remained during the epidemic and was less influenced by COVID-19 preventative policies.

Comparative Evaluation of LAMP and Nested PCR for the Rapid Diagnosis of Mycobacterium marinum Infection.

Purpose: Culture of Mycobacterium marinum is very time-consuming, taking several weeks to produce positive results. Seeking rapid and sensitive diagnostic methods for diagnosis can greatly improve patient treatment. Our study aimed to compare the rapid diagnostic abilities of polymerase chain reaction (PCR), nested PCR and loop mediated isothermal amplification (LAMP) of detecting M. marinum in skin samples from patients with M. marinum infection. Methods: A total of 6 M. marinum strains and 6 skin samples with definite diagnosis of M. marinum infection were included in the study. We optimized LAMP performance for detection of M. marinum genomic DNA and confirmed the specificity of the primers. Then, the sensitivity of the LAMP and nested PCR assays were assessed by M. marinum strains and clinical samples. Results: Nested PCR was 10-fold more sensitive than the LAMP assay by serial dilution of M. marinum DNA. PCR positive samples were all positive by LAMP detection of 6 clinical M. marinum strains. Out of 6 clinical skin specimens confirmed as M. marinum infection, 0 (0%), 3 (50%), 3 (50%), and 4 (66.6%) were positive by PCR, nested PCR, LAMP and culture. The LAMP shared the same sensitivity than nested PCR in M. marinum strains and clinical samples, but it was easy to perform and faster than nested PCR assay. Conclusion: Compared with conventional PCR, LAMP and nested PCR are more sensitive and have a higher detection rate of M. marinum in clinical skin specimens. The LAMP assay proved to be more suitable for rapid diagnosis of M. marinum infection in a shorter time, especially in resource-limited settings.