Journal of Microbiology Immunology and Infection最新文献

Background/purpose(s): Psoriasis is a skin-specific autoimmune disease that causes scaling, erythema and thickening. The disease involves immune cell infiltration and keratinocyte proliferation in skin lesions. Previous studies have demonstrated that Th17 cells and IL-22 play prominent roles in the pathogenesis of psoriasis via IL-17, IL-22 and IL-23 signaling. However, the role of innate cells in this process remains unclear.

Methods: In this study, using the TLR7/8 agonist imiquimod (IMQ) in a well-established murine model, we demonstrated that natural killer (NK) cells play an important role in the pathogenesis of psoriasis. Non-obese diabetic (NOD) mice are prone to Th1 and Th17 responses, and the lack of NK cell activity and macrophages in these animals contribute to their value as a model for type I diabetes.

Results: The NOD mice treated with IMQ (NOD-IMQ) exhibit markedly attenuated skin lesions compared to BALB/c mice treated with IMQ (BALB/c-IMQ). An analysis of immune cell types revealed that the number of macrophages, plasmacytoid dendritic cells (pDCs), neutrophils and Th1, Th2, Th17, Treg, and NK cells increased in the BALB/c-IMQ mice compared to the NOD-IMQ mice. Testing NK cell activity and macrophage function, NK cell cytotoxicity and macrophage phagocytosis, but not macrophage migration, were decreased in the NOD mice compared with the BALB/c mice. After NK cell depletion, normal BALB/c-IMQ mice exhibited milder skin lesions than the NOD-IMQ mice.

Conclusion: These results suggest that NK cells play a critical role in IMQ-induced skin inflammation. Controlling NK cell activity may be a potential therapeutic approach for psoriasis.

Background: Outsourced hospital services may pose underrecognized risks for healthcare-associated infections, particularly in high-risk areas such as neurosurgery. A cluster of Klebsiella aerogenes infections in a neurosurgical ward prompted an investigation to identify the source and transmission route.

Methods: A retrospective outbreak investigation was conducted in the neurosurgical department of a 2600-bed tertiary care hospital in Taiwan between August 2023 and May 2024. The investigation included an epidemiological review, environmental sampling, and molecular typing using pulsed-field gel electrophoresis (PFGE).

Results: The index case, a 56-year-old woman who underwent craniectomy on August 31, 2023, developed K. aerogenes infection one week postoperatively and died 18 days later. Seventeen additional cases were identified-12 from September 2023 to January 2024, and 5 between April and May 2024. All patients had undergone preoperative hair shaving by an outsourced barber department. PFGE analysis of 10 patient isolates revealed that 8 shared clonal strain A. Environmental samples from two of four shampoo carts used by the outsourced barber service also yielded strain A. Although initial infection control efforts temporarily reduced case numbers, a resurgence in April 2024-with four new cases and repeated recovery of strain A from equipment-confirmed the ongoing transmission source. Staff stool samples were negative, implicating contaminated equipment rather than personnel. After discontinuing the barber service and replacing equipment, no further cases occurred as of November 2024.

Conclusion: This outbreak highlights the importance of incorporating non-clinical outsourced services into infection surveillance and control programs, especially in high-risk clinical settings.

Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) still evolves and spreads worldwide. Mucosal immunity is the first line of defense against SARS-CoV-2 infections. We tested the hypothesis of whether salivary antibodies (sIgA or IgG) induced by common human coronaviruses (HCoVs) have cross-reactivities and neutralizing effects against SARS-CoV-2.

Methods: Paired saliva and serum samples were collected from healthy young adults (n = 98) in 1993 and uninfected healthcare workers during the pandemic (n = 79). sIgA and IgG antibodies against SARS-CoV-2 and HCoV-229E were detected, respectively.

Results: A moderate to strong positive correlation was found between levels of anti-SARS-CoV-2 and anti-HCoV-229E sIgA and IgG in saliva. Specific anti-S of SARS-CoV-2 IgA were found in 14 % of saliva, whereas neither anti-NP nor anti-S IgG were found in serum collected in the pre-pandemic era. Cross-reactivities of these sustained anti-HCoVs sIgA or IgG were enriched and confirmed by immunoblotting and also exhibited neutralizing activities against SARS-CoV-2 and its variants using Luminex-based assay. Furthermore, the incidence rate ratios of subsequent SARS-CoV-2 infection were significantly lower in the healthcare workers group with high salivary anti-HCoV-229E S1 sIgA.

Conclusion: Our findings suggest that salivary anti-HCoV-229E S1 sIgA antibodies with cross-reactivities against SARS-CoV-2 S1 protein may pose protective potential against SARS-CoV-2.

Background: The imbalance of human microbiota has been associated with various inflammatory disease. Compared to intestinal flora, the esophageal microbiome has been understudied,and it remains unclear whether dysbiosis is related to reflux esophagitis (RE) and Barrett's esophagus (BE).This study aimed to synthesize findings on microbial composition changes across different regions of the gastrointestinal tract and their relationship with chronic esophageal reflux diseases.

Methods: We recruited 29 RE patients (10 Grade A; 10 Grade B; 9 Grade C), 9 BE patients, and 10 healthy volunteers to study microbial composition in saliva, gastric juice, and stool using 16S rRNA gene pyrosequencing and analyzed serum inflammatory cytokines using ELISA.

Results: Microbiota alpha diversity exhibited no significant changes between groups. In terms of taxonomy, RE and BE patients had more gram-negative anaerobic bacteria in salivary microbiota. Notably, increased Tannerellaceae abundance correlated with elevated serum IL-6 levels, which have been linked to chronic inflammation. Helicobacter was more abundant in gastric fluid of controls. Stool analysis revealed BE patients had higher abundance of phylum Bacteroidetes, and the genus Prevotella, while Fusobacterium was more prevalent in controls.

Conclusions: The increased abundance of Tannerellaceae in saliva was correlated with elevated serum IL-6 levels and may be a contributing factor in chronic esophageal reflux disease. BE patients had a higher abundance of Prevotella, a gram-negative bacterium, which may be linked to early stage esophageal inflammation in chronic reflux disease. Conversely, the increased abundance of Helicobacter in gastric juice may serve as a protective factor.

Objective: The global rise of carbapenem-resistant Klebsiella pneumoniae bloodstream infection (CRKP-BSI) is alarming due to its link to increased morbidity and mortality from limited treatment options. This study evaluated the impact of virulence plasmid carriage on CRKP-BSI mortality.

Methods: A matched case-control study was conducted among 93 CRKP patients, 23 of whom tested positive for virulence plasmids. The clinical and bacterial characteristics of CRKP-induced BSIs with and without virulence plasmids were analyzed.

Results: Virulence plasmids were present in 24.7 % of CRKP strains, with a 61.1 % mortality rate among patients with virulence plasmid-positive CRKP (pV-CRKP) infections. The ST11-KL64 subtype was predominant in Jiangxi Province. Molecular typing revealed pV-CRKP strains primarily had two identical genotypes, yet virulence plasmids were present across various PFGE genotypes, indicating polymorphic distribution. Logistic regression identified community-acquired infection, neurology department admission, and stroke as independent risk factors. G. mellonella and biofilm assays showed most CRKP strains with virulence plasmids exhibited increased virulence, though some strains did not.

Conclusion: Virulence plasmids generally heighten CRKP strain virulence and directly affect the 7-day survival rate. Certain strains carry virulence plasmids without increased virulence. Community-acquired infection, neurology department admission, and stroke are independent risk factors for pV-CRKP strains. The presence of IncFrepB among pV-CRKP may promote the spread of virulence genes in ST11-type CRKP.

Background: Rhodococcus equi is a facultative intracellular pathogen that causes severe infections in foals and immunocompromised individuals. Its ability to survive within macrophages renders conventional antibiotics ineffective and promotes multidrug resistance. Novel therapeutic strategies are needed.

Methods: We screened a library of 3251 natural compounds to identify antibacterial candidates targeting R. equi. Strains included wild-type 103S⁺, an mrx-deficient triple mutant, and a biosensor-expressing strain carrying the Mrx1-roGFP2 probe. Minimal inhibitory concentrations, checkerboard synergy assays, and time-kill kinetics were performed. Intracellular efficacy was assessed in infected J774.A1 murine macrophages. Redox stress induction was quantified using confocal microscopy.

Results: Thirty-eight compounds selectively inhibited the mrx-deficient mutant, suggesting redox-mediated mechanisms. While most natural compound combinations showed limited intracellular activity, the pairing of erythromycin (ERY) and cinchonidine (CIN) exhibited synergy, significantly reducing intracellular bacterial load. Time-kill assays revealed bactericidal activity at 8 × MIC. Biosensor analysis confirmed that ERY-CIN synergy correlated with elevated oxidative stress, supporting a redox-based mechanism.

Conclusions: Our findings highlight CIN as a redox-active adjuvant that potentiates erythromycin's intracellular efficacy against R. equi. This combinatorial approach targets redox homeostasis and enhances bacterial clearance, providing a promising strategy against multidrug-resistant intracellular pathogens.

Background: Toxocara sp. is the most common nematode in zoonotic helminth diseases worldwide. However, data on this issue remain limited in Vietnam, particularly regarding Toxocara seroprevalence in various geographical regions.

Methods: A retrospective study was conducted on 46,284 venous blood samples from suspected toxocariasis patients across various geographical regions, which were tested at the laboratories of the Medlatec Healthcare System in Vietnam in 2023. The presence of total IgE levels and Toxocara IgG antibodies was determined using ELISA kits. Risk factors such as age, gender, geographical region, high IgE concentration (>130 IU/mL), and eosinophilia (>500 cells/μl) were evaluated.

Results: Toxocara IgG antibodies were found in 47.63 % of patients (95 % CI: 47.18-48.09). The seroprevalence of human toxocariasis was significantly different between individuals over 60 years of age and those under 60 years. The rates of IgG antibodies against Toxocara also varied significantly between different geographical regions. Accordingly, the highest seroprevalence was observed in the North Central region (59.79 %), followed by the Northern Mountainous region (51.34 %), Red River Delta (42.79 %), South West (39.91 %), South Central (36.97 %), Central Highlands (35.78 %), and South East (33.10 %), respectively. A significant association was found between eosinophilia, high IgE concentrations, and Toxocara seropositivity (p < 0.001).

Conclusion: The seropositivity rate to Toxocara spp. in different geographical regions in Vietnam in the year 2023 was relatively high. Further studies are needed to better understand the clinical relevance of these findings and to evaluate the feasibility and cost-effectiveness of targeted screening and control strategies.