Microbiology and Immunology最新文献

This study assessed the role of high mobility group box 1 (HMGB1) in pneumococcal pneumonia. Intratracheal challenge of mice with Streptococcus pneumoniae significantly increased HMGB1 levels in bronchoalveolar lavage fluid. Immunostaining of lung sections revealed HMGB1 localization in both alveolar epithelial and infiltrating polymorphonuclear cells in S. pneumoniae-infected mice. In vitro, pneumolysin, a pore-forming pneumococcal toxin, causes HMGB1 release from neutrophils. Additionally, recombinant HMGB1 enhanced TNF-α production in RAW264.7 macrophages, human neutrophils, and THP-1 cells. These findings indicate that neutrophil-derived HMGB1 serves as a pro-inflammatory mediator and exacerbates of lung inflammation during pneumococcal infection.

To accelerate the development of antiviral drugs, we generated human iPS cell-derived myeloid cell lines, which were susceptible to SARS-CoV-2 infection. Viral isolation using clinical specimens showed that some novel cell lines performed better than VeroE6/TMPRSS2. In addition, viral genome mutations that occurred during viral passaging did not happen in VeroE6/TMPRSS2 but accumulated in these cell lines, and those mutations were reported in clinical specimens. Furthermore, the antiviral efficacy of remdesivir differed among the cell types. These findings suggest that the novel myeloid cell lines may serve as a useful platform for virus isolation and the evaluation of antiviral responses.

This study compared bacterial counts and composition in plastic-bottled green tea beverages immediately after direct drinking and after storage at 37°C for 1 day. Immediately after drinking, (1.9 ± 1.6) × 10³ and (4.5 ± 3.9) × 10³ colony forming units (CFU)/mL were recovered from standard green tea and strong green tea, respectively. After 1 day of storage, (1.3 ± 1.5) × 10⁴ and (1.6 ± 3.1) × 10³ CFU/mL were recovered from standard green tea and strong green tea, respectively. Following storage, Lacticaseibacillus spp., Streptococcus, and Veillonella were isolated from both beverages.

Influenza pneumonia is characterized by excessive inflammatory responses that contribute to severe lung injury and mortality. Supersulfides, endogenously produced cysteine-derived persulfides and polysulfides, exert potent antioxidant, anti-ferroptotic, and anti-inflammatory activities; however, their therapeutic potential after disease onset remains unclear. Here, we investigated the efficacy of N-acetylcysteine tetrasulfide (NAC-S2), a highly water-soluble and cell-permeable supersulfide donor, in a mouse model of influenza A virus (IAV)-induced pneumonia. Subcutaneous administration of NAC-S2 rapidly elevated systemic levels of cysteine- and glutathione-derived supersulfides. In therapeutic treatment starting 2 days post-infection, when body weight loss and clinical signs had already developed, NAC-S2 significantly improved survival and mitigated body weight loss compared with vehicle and oxidized NAC controls. Metabolomic analysis revealed that influenza virus infection depleted lung glutathione persulfide (GSSH), while NAC-S2 effectively restored tissue GSSH levels. NAC-S2 treatment markedly reduced pulmonary interleukin (IL)-1β and IL-6 production without affecting viral load or Type-I interferon responses. Furthermore, NAC-S2 suppressed NLRP3 inflammasome activation and gasdermin D expression, leading to decreased infiltration of CD3⁺ T cells and myeloperoxidase-positive neutrophils. Histopathological analyses confirmed that NAC-S2 ameliorated epithelial injury, interstitial edema, and hemorrhage in infected lungs. Collectively, our findings demonstrate that NAC-S2 exerts therapeutic benefit even after the onset of severe influenza pneumonia, primarily by replenishing supersulfides and alleviating excessive inflammatory responses. Supersulfide donors represent a promising class of adjunctive therapeutics for severe viral pneumonia.

Among the three prion strains of bovine spongiform encephalopathy (BSE), classical BSE (C-BSE) prions are known causative agents of variant Creutzfeldt-Jakob disease. By contrast, human infections with L-type (L-) or H-type (H-) BSE prions have not been reported. Nonetheless, the zoonotic potential of L-BSE prions is supported by their successful primary transmission from cattle to cynomolgus macaque (Macaca fascicularis) monkeys via intracranial challenge. To assess whether the defining strain traits of L-BSE prions remain stable following secondary intraspecies transmission, we prepared brain homogenates from a diseased macaque that had previously undergone primary transmission of L-BSE prions, and intracranially administered them into two naïve macaques. Both animals succumbed to the disease within humane endpoints comparable to those observed in the primary transmission. Histopathological and immunohistochemical analyses of brain tissues showed no significant changes relative to primary transmission, including severe vacuolation and fine synaptic distribution of disease-associated forms of prion protein (PrP^Sc) in the cerebrum, and sparse PrP^Sc plaques in the cerebellum. In bioassays using C57BL/6 J mice, cattle-derived L-BSE prions and those passaged once or twice in macaques failed to transmit to mice, whereas cattle-derived C-BSE prions and their macaque-passaged counterparts were transmissible. These findings refine our understanding of L-BSE pathogenesis and confirm the stability of L-BSE prions following intracranial transmission in a nonhuman primate model.

Orthohantaviruses are a genus of zoonotic viruses from the family Hantaviridae, which is primarily known for their ability to cause severe human diseases. The virus is primarily known for causing two major human diseases, hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome. However, the frequency of this infection remains largely unknown. Hence, the aim of this study was to diagnose patients infected with Orthohantavirus in India. We tested serum samples from 216 febrile patients, presented at Lisie Hospital, Kochi, for positive anti-orthohantavirus IgM and IgG antibodies. All the participating patients were negative for dengue and scrub typhus IgM antibodies. In total, 16.20% (n = 35) of the febrile patients were positive for anti-orthohantavirus IgM and 11.57% (n = 25) for anti-orthohantavirus IgG antibodies. Anti-orthohantavirus IgM and IgG both were detected in 4.63% (n = 10) of the enrolled subjects. In total, 51.43% of the IgM-positive patients had a final diagnosis of either viral fever or acute febrile disease, with only two patients reported to have contact with rodents, and none of these patients had traveled outside of their place of residence. Orthohantavirus infections may be endemic in India, as their hosts are omnipresent. However, the lack of proper diagnostic tools and limited awareness of these emerging infections amongst doctors in India reduces the diagnosis of the disease. Therefore, there is a pressing need for educating healthcare providers about the circulation of orthohantaviruses in India. There is an urgent need for the development of serotype-specific, affordable, and accurate diagnostic tools for early diagnosis of orthohantavirus infections.

Chromoblastomycosis (CBM) is a chronic skin and subcutaneous infection mainly caused by Fonsecaea pedrosoi, a dematiaceous fungus with various morphotypes. Characteristic sclerotic cells-globe-shaped, multiseptated and pigmented-are found in lesions of infected individuals, though their differentiation in the host remains poorly understood. To evaluate in vitro activity of five antifungal drugs-itraconazole (ITZ), posaconazole (PCZ), voriconazole (VCZ), fluconazole (FCZ), and caspofungin (CAS)-against Fonsecaea spp. conidia or sclerotic cells, assessing their minimum inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) and correlated the ITZ MIC with patients' clinical evolution. Forty-three clinical isolates of Fonsecaea spp. and the F. pedrosoi strain ATCC 46428 were assessed for susceptibility to ITZ, PCZ, VCZ, FCZ, and CAS following Clinical Laboratory Standard Institute guidelines (CLSI) (document M38-A2). MIC values were determined after 5 days of incubation at 30°C, followed by MFC determination, with geometric mean MIC (GMMIC) and MFC (GMMFC) used for comparison. PCZ was the most effective antifungal drug, with geometric mean MICs of 0.3 µg/mL (conidia) and 1 µg/mL (sclerotic), and MFCs of 2.98 and 6.72 µg/mL, respectively. Clinical follow-up revealed that higher ITZ MIC values (0.9 µg/mL) correlated with poor patient outcomes compared to lower values in improved or cured patients. These findings highlight PCZ and VCZ as promising options for CBM treatment, especially for patients not responding to ITZ.

Enterococci are commensal bacteria in humans that are found in the intestine, pharynx and oral cavity and sometimes cause opportunistic infections such as intra-abdominal infections and bacteraemia. Several enterococcal species, especially E. faecium and E. faecalis, have become clinical problems as drug-resistant bacteria, including vancomycin-resistant Enterococci (VRE). Therefore, new antibacterial agents against enterococcal infections are needed. Because several fatty acids (FAs) have been reported to possess antibacterial activity, in this study, the effects of 3 unsaturated fatty acids on enterococci were evaluated using clinically isolated strains. Among the 3 fatty acids we tested, linoleic acid (LA) and palmitoleic acid (POA) exhibited antibacterial activity against E. faecalis and E. faecium. Next, we evaluated the antibacterial activities of the two FAs against 126 enterococcal clinical strains, including five different species. The minimum inhibitory concentration (MIC) of LA varied among bacterial species and strains (ranging from 37.5 to 1200 μM), while the MIC of POA was similar (ranging from 37.5 to 150 μM). Among species, E. faecium strains presented higher MICs than E. faecalis, E. avium and E. casseliflavus strains. In 6 VRE strains, the MICs of LA showed variable (150-1200 μM), whereas MICs of POA were constant at 75 μM. We subsequently investigated the combined effects of LA and POA with several antibiotics and found that LA had synergistic effects with β-lactam, gentamicin, ciprofloxacin and vancomycin against E. faecalis and E. faecium strains, including VRE, whereas POA did not have a significant effect. Our results indicate the potential application of FAs for enterococcal infection.

Bovine leukemia virus (BLV) is widespread globally and causes economic losses in the cattle industry. Shandong Province plays a significant role in China's livestock industry, with an increasing importance in food of Holstein and Angus cattle. However, BLV prevalence in Holstein and Angus breeds in Shandong Province remains unclear. In particular, there are no reports of BLV prevalence of Angus cattle in field surveys worldwide. In this study, 613 samples from six large-scale farms (> 1000 heads per farm) in Binzhou and Weifang cities were screened for BLV antibodies (gp51) using an enzyme-linked immunosorbent assay. The samples included 303 Angus (beef) and 310 Holstein (dairy) cattle. All Angus breeding samples from the three farms were BLV-negative at both the animal- and herd-level prevalences. In contrast, 62 of 310 Holstein cattle (20.0%) from three dairy farms were positive for BLV antibodies. For example, 35/110 (31.8%), 19/100 (19.0%), and 8/100 (8.0%) samples from the D, E, and F farms, respectively, were BLV-positive. Notably, the animal- and herd-level prevalences for Holstein cattle exhibited 20% and 100% positivity, respectively. These findings offer significant insights into the BLV status of Holstein and Angus cattle in Shandong Province, China.