Differential immune responses to Segniliparus rotundus and Segniliparus rugosus infection and analysis of their comparative virulence profiles

Comparison of Macrophage Immune Responses and Metabolic Reprogramming in Smooth and Rough Variant Infections of Mycobacterium mucogenicum

Mycobacterium mucogenicum (Mmuc), a rapidly growing nontuberculous mycobacterium (NTM), can infect humans (posttraumatic wound infections and catheter-related sepsis). Similar to other NTM species, Mmuc exhibits colony morphologies of rough (Mmuc-R) and smooth (Mmuc-S) types. Although there are several case reports on Mmuc infection, no experimental evidence supports that the R-type is more virulent. In addition, the immune response and metabolic reprogramming of Mmuc have not been studied on the basis of morphological characteristics. Thus, a standard ATCC Mmuc strain and two clinical strains were analyzed, and macrophages were generated from mouse bone marrow. Cytokines and cell death were measured by ELISA and FACS, respectively. Mitochondrial respiration and glycolytic changes were measured by XF seahorse. Higher numbers of intracellular bacteria were found in Mmuc-R-infected macrophages than in Mmuc-S-infected macrophages. Additionally, Mmuc-R induced higher levels of the cytokines TNF-α, IL-6, IL-12p40, and IL-10 and induced more BMDM necrotic death. Furthermore, our metabolic data showed marked glycolytic and respiratory differences between the control and each type of Mmuc infection, and changes in these parameters significantly promoted glucose metabolism, extracellular acidification, and oxygen consumption in BMDMs. In conclusion, at least in the strains we tested, Mmuc-R is more virulent, induces a stronger immune response, and shifts bioenergetic metabolism more extensively than the S-type. This study is the first to report differential immune responses and metabolic reprogramming after Mmuc infection and might provide a fundamental basis for additional studies on Mmuc pathogenesis.

The Associations Between Sociodemographic Characteristics and Trust in Physician With Immunization Service Use in U.S. Chinese Older Adults

This study investigated sociodemographic factors for immunization care use and the relationship between trust in physician (TIP) and immunization service use in older Chinese Americans. Data were collected through the Population Study of Chinese Elderly, including survey information of 3,157 older adults in the Greater Chicago area. Regression results showed that the odds of getting vaccinated were higher for those who were older, female, and had higher education and income. After adjusting for the covariates, higher TIP was associated with greater immunization service use. The highest tertile of TIP was associated with higher odds of using immunization service (OR 2.19, 95% CI [1.76, 2.72]), especially for flu and pneumonia vaccines. Findings suggests that immunization service use may be increased by improving TIP and promoting targeted health care management plans for racial/ethnic minorities, which is highly relevant to increase the vaccination rate and contain the pandemic as the COVID-19 vaccine is available.

Aerobic Actinomycetes of Clinical Significance

The group of Gram-positive bacillary organisms broadly known as "aerobic actinomycetes" consists of heterogeneous and taxonomically divergent genera. They are found in a wide variety of natural and man-made environments but are rarely considered a part of the normal human flora, with infections normally originating from exogenous sources. An extensive number of genera have been described, but only a minority of these has been associated with human or veterinary health. The association with human disease is usually of an opportunistic nature, either through accidental means of inoculation or through involvement with immunocompromising conditions in the host. They cause a wide spectrum of diseases in humans, which may differ greatly between the genera and even between species, but which also may have a great amount of overlap. The occurrence of such infections is probably greater than appreciated, since many may go unrecognized. Etiologic prevalence of specific genera and species varies geographically within the United States and worldwide. Traditional phenotypic identification methods for separation of the many genera and species of aerobic actinomycetes have found great difficulties. Recent use of chemotaxonomic analyses and emerging technologies such as molecular analysis of nucleic acids, and more recently proteomics for identification to the genus/species level, has provided a far more robust technique to understand the organisms' relatedness, distribution, epidemiology, and pathogenicity in humans.

A Novel Therapeutic Approach Using Mesenchymal Stem Cells to Protect Against Mycobacterium abscessus

Recent studies have demonstrated the therapeutic potential of mesenchymal stem cells (MSCs) for the treatment of acute inflammatory injury and bacterial pneumonia, but their therapeutic applications in mycobacterial infections have not been investigated. In this study, we demonstrated the use of MSCs as a novel therapeutic strategy against Mycobacterium abscessus (M. abscessus), which is the most drug-resistant and difficult-to-treat mycobacterial pathogen. The systemic intravenous injection of MSCs not only improved mouse survival but also enhanced bacterial clearance in the lungs and spleen. Additionally, MSCs enhanced IFN-γ, TNF-α, IL-6, MCP-1, nitric oxide (NO) and PGE2 production and facilitated CD4(+) /CD8(+) T cell, CD11b(high) macrophage, and monocyte recruitment in the lungs of M. abscessus-infected mice. To precisely elucidate the functions of MSCs in M. abscessus infection, an in vitro macrophage infection system was used. MSCs caused markedly increased NO production via NF-κB activation in M. abscessus-infected macrophages cultured in the presence of IFN-γ. Inhibiting NO or NF-κB signaling using specific inhibitors reduced the antimycobacterial activity of MSCs. Furthermore, the cellular crosstalk between TNF-α released from IFN-γ-stimulated M. abscessus-infected macrophages and PGE2 produced by MSCs was necessary for the mycobacterial-killing activity of the macrophages. Finally, the importance of increased NO production in response to MSC administration was confirmed in the mouse M. abscessus infection model. Our results suggest that MSCs may offer a novel therapeutic strategy for treating this drug-resistant mycobacterial infection by enhancing the bacterial-killing power of macrophages. Stem Cells 2016;34:1957-1970.

Linking operation parameters and environmental variables to population dynamics of Mycolata in a membrane bioreactor

The community structure and population dynamics of Mycolata were monitored in a full-scale membrane bioreactor during four experimental phases under changing operating and environmental conditions, by means of temperature-gradient gel electrophoresis of partial 16S-rRNA genes amplified from community DNA and RNA templates (total and active populations). Non-metric multidimensional scaling and BIO-ENV analyses demonstrated that population dynamics were mostly explained (30-32%) by changes in the input of nutrients in the influent water and the accumulation of biomass in the bioreactors, while the influence of hydraulic and solid retention times, temperature and F/M ratio was minor. Significant correlations were observed between particular Mycolata phylotypes and one or more variables, contributing information for the prediction of their abundance and activity under changing conditions. Fingerprinting and multivariate analyses demonstrated that two foaming episodes, recorded at temperatures <20°C, were connected to the increase of the relative abundance of Mycolata unrelated to Gordonia amarae.

Genomic and proteomic features of mycobacteriophage SWU1 isolated from China soil

Mycobacteriophage SWU1 is a newly isolated phage from soil sample collected in Sichuan province, China using Mycobacterium smegmatis mc(2)155 as host. Plaque, phage morphology and one-step growth curve were characterized. The complete genomic sequence of phage SWU1 was determined by shotgun sequencing. The ends of SWU1 were determined. Structural proteins of SWU1 were analyzed by NanoLC-ESI-MS/MS. Seven ORFs were identified as structural protein encoded by SWU1 genome. The genetic basis underlying the SWU1 plaque was explored using comparative genomics. Prophages homologous to SWU1 were identified in two pathogens, Segniliparus rugosus ATCC BAA-974 and Mycobacterium rhodesiae JS60. Genus Segniliparus is a member of the order Corynebacteriales. To our knowledge, this is the first report of Mycobacterium prophages in different genera.