Infectious microbes & diseases最新文献

A recent outbreak of coronavirus disease 2019 (COVID-19) caused by the single-stranded enveloped RNA virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has developed into a global pandemic, after it was first reported in Wuhan in December 2019. SARS-CoV-2 is an emerging virus, and little is known about the basic characteristics of this pathogen, the underlying mechanism of infection, and the potential treatments. The immune system has been known to be actively involved in viral infections. To facilitate the development of COVID-19 treatments, the understanding of immune regulation by this viral infection is urgently needed. This review describes the mechanisms of immune system involvement in viral infections and provides an overview of the dysregulation of immune responses in COVID-19 patients in recent studies. Furthermore, we emphasize the role of gut microbiota in regulating immunity and summarized the impact of SARS-CoV-2 infection on the composition of the microbiome. Overall, this review provides insights for understanding and developing preventive and therapeutic strategies by regulating the immune system and microbiota.

Heart failure (HF) is a global public health problem, with morbidity and mortality increasing year by year. The gut microbiome actively affects the physiological and pathological activities of the human body in a variety of ways. More and more studies have suggested a strong correlation between HF and gut microbiome metabolites. Our review summarizes the specific alteration of these metabolites and their connection to the progression of HF, aiming at considering new approaches toward regulating the gut microbiome and using its metabolic pathways to treat HF, potentially decreasing the morbidity and mortality of HF as well as improving prognosis.

Invasive infection caused by Streptococcus pyogenes emm89 strains has been increasing in several countries linked to a recently emergent clade of emm89 strains, designated clade 3. In Japan, the features of emm89 S. pyogenes strains, such as clade classification, remains unknown. In this study, we collected emm89 strains isolated from both streptococcal toxic shock syndrome (STSS) (89 STSS isolates) and noninvasive infections (72 non-STSS isolates) in Japan from 2011 to 2019, and conducted whole-genome sequencing and comparative analysis, which resulted in classification of a large majority into clade 3 regardless of disease severity. In addition, invasive disease-associated factors were found among emm89 strains, including mutations of control of virulence sensor, and absence of the hylP1 gene encoding hyaluronidase. These findings provide new insights into genetic features of emm89 strains.

A number of studies have suggested that coronavirus disease 2019 (COVID-19) can cause liver damage. However, clinical features and outcome of COVID-19 in patients with liver injury remain to be further investigated. In this study, the clinical data of 265 COVID-19 patients admitted to seven tertiary hospitals were collected. Based on a threshold for transaminase or total bilirubin levels at two times the normal upper limit, patients were divided into mild or moderate/severe liver injury groups. Among the 265 patients, 183 patients showed liver injury within 48 hours of admission. Aspartate aminotransferase levels were predominantly elevated in the liver injury group, but albumin levels were reduced. Moreover, fibrinogen and D-dimer were significantly increased. Furthermore, 68% of the patients with moderate/severe liver injury had one or more underlying diseases. Almost half of these patients developed acute respiratory distress syndrome (44%) and secondary infections (46%). These patients showed increased interleukin-6 and interleukin-10 levels and a decrease in PaO₂ and the oxygenation index. In addition, levels of alanine aminotransferase, aspartate aminotransferase, and albumin were correlated with the oxygenation index, D-dimer and lymphocyte counts. Furthermore, a novel prognostic assessment model based on liver function was established, which accuracy reached 88% and was able to accurately assess the prognosis of COVID-19 patients.

Following the discovery of the Bacillus Calmette-Guerin (BCG) vaccine, its efficacy against Mycobacterium tuberculosis was soon established, with several countries adopting universal BCG vaccination schemes for their populations. Soon, however, studies aimed to further establish the efficacy of the vaccine in different populations discovered that the vaccine has a larger effect in reducing mortality rate than could be explained by its effect on tuberculosis alone, which sparked suggestions that the BCG vaccine could have effects on other unrelated or non-mycobacterial pathogens causing diseases in humans. These effects were termed heterologous, non-specific or off-target effects and have been shown to be due to both innate and adaptive immune system responses. Experiments carried out in a bid to further understand these effects led to many more discoveries about the applicability of the BCG vaccine for the prevention, diagnosis, and treatment of certain disease conditions. As we approach the second century since the discovery of the vaccine, we believe it is timely to review these interesting applications of the BCG vaccine, such as in the prevention of diabetes, atherosclerosis, and leukemia; the diagnosis of Kawasaki disease; and the treatment of multiple sclerosis, non-muscle invading bladder cancer, and stage III melanoma. Furthermore, complications associated with the administration of the BCG vaccine to certain groups of patients, including those with severe combined immunodeficiency and HIV, have been well described in literature, and we conclude by describing the mechanisms behind these complications and discuss their implications on vaccination strategies, especially in low-resource settings.

Vibrio cholerae, the causative agent of the infectious disease, cholera, is commonly found in brackish waters and infects human hosts via the fecal-oral route. V. cholerae is a master of stress resistance as V. cholerae's dynamic lifestyle across different physical environments constantly exposes it to diverse stressful circumstances. Specifically, V. cholerae has dedicated genetic regulatory networks to sense different environmental cues and respond to these signals. With frequent outbreaks costing a tremendous amount of lives and increased global water temperatures providing more suitable aquatic habitats for V. cholerae, cholera pandemics remain a probable catastrophic threat to humanity. Understanding how V. cholerae copes with different environmental stresses broadens our repertoire of measures against infectious diseases and expands our general knowledge of prokaryotic stress responses. In this review, we summarize the regulatory mechanisms of how V. cholerae fights against stresses in vivo and in vitro.