Infectious microbes & diseases最新文献

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.

Escherichia coli is a prevalent causative pathogen of spontaneous bacterial peritonitis (SBP). In this retrospective study, we investigated the microbiological characteristics and antibiotic susceptibility of E. coli clinical isolates obtained from liver cirrhosis patients suffering from nosocomial SBP. Our results showed that extended-spectrum β-lactamase (ESBL)-producing E. coli accounted for 47% of the cases, while 62% of the isolates were multi-drug resistant (MDR) pathogens. ESBL-producing and MDR isolates showed high incidences of resistance to third-generation cephalosporins, but they displayed susceptibility to carbapenems, β-lactamase inhibitors, and aminoglycosides. Importantly, liver cirrhosis patients with MDR E. coli SBP showed a significantly higher death rate than patients with non-MDR infections (P = 0.021). The 30-day mortality of nosocomial SBP was independently correlated with female gender [odds ratio (OR) = 5.200, 95% confidence interval (CI) = 1.194-22.642], liver failure (OR = 9.609, 95% CI = 1.914-48.225), hepatocellular carcinoma (OR = 8.176, 95% CI = 2.065-32.364), hepatic encephalopathy (OR = 8.176, 95% CI = 2.065-32.364), model of end-stage liver disease score (OR = 1.191, 95% CI = 1.053-1.346), white blood cell count (OR = 0.847, 95% CI = 0.737-0.973), and ascites polymorphonuclear (OR = 95.903, 95% CI = 3.410-2697.356). In conclusion, third-generation cephalosporins may be inappropriate for empiric treatment of nosocomial SBP caused by E. coli, due to the widespread presence of ESBLs and high incidence of MDR pathogens.

The recently emerged coronavirus disease 2019 (COVID-19) has rapidly evolved into a pandemic with over 10 million infections and over 500 thousand deaths. There are currently no effective therapies or vaccines available to protect against this coronavirus infection. In this review, we discuss potential therapeutic options for COVID-19 based on the available information from previous research on severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Substantial efforts are underway to discover new therapeutic agents for COVID-19, including the repurposing of existing agents and the development of novel agents that specifically target SARS-coronavirus 2 (SARS-CoV-2) or host factors. Through the screening of compound libraries, various classes of drugs, such as ribavirin, remdesivir, lopinavir/ritonavir, and hydroxychloroquine have been identified as potential therapeutic candidates against COVID-19. Novel antiviral drugs for SARS-coronavirus 2 are being developed to target viral enzymes or functional proteins, as well as host factors or cell signaling pathways.

The pandemic of coronavirus disease 2019 (COVID-19), a respiratory disease caused by a novel severe acute respiratory syndrome coronavirus-2, is causing substantial morbidity and mortality. Along with the respiratory symptoms, underlying diseases in senior patients, such as diabetes, hypertension, and coronary heart disease, are the most common comorbidities, which cause more severe outcomes and even death. During cellular attachment and entry of severe acute respiratory syndrome coronavirus-2, the key protein involved is the angiotensin I converting enzyme 2 (ACE2), which is located on the membrane of host cells. Here, we aim to curate an expression profile of Ace2 and other COVID-19 related genes across the available diabetes murine strains. Based on strictly manual curation and bioinformatics analysis of the publicly deposited expression datasets, Ace2 and other potentially involved genes such as Furin, Tmprss2, Ang, and Ang2 were examined. We found that Ace2 expression is rather ubiquitous in three selected diabetes prone strains (db/db, ob/ob and diet-induced obese). With the most abundant datasets present, the liver shows a medium Ace2 expression level compared with the lungs, pancreatic islets, brain and even T cells. Age is a more critical factor for Ace2 expression in db/db compared with the other two strains. Besides Ace2, the other four host genes showed varied levels of correlation to each other. To accelerate research on the interaction between COVID-19 and underlying diseases, the Murine4Covid transcriptomics database (www.geneureka.org/Murine4Covid) will facilitate the design of research on COVID-19 and comorbidities.

Background: Regarding to the actual situation of the new coronavirus disease 2019 epidemic, social factors should be taken into account and the increasing growth trend of confirmed populations needs to be explained. A proper model needs to be established, not only to simulate the epidemic, but also to evaluate the future epidemic situation and find a pilot indicator for the outbreak.

Methods: The original susceptible-infectious-recover model is modified into the susceptible-infectious-quarantine-confirm-recover combined with social factors (SIDCRL) model, which combines the natural transmission with social factors such as external interventions and isolation. The numerical simulation method is used to imitate the change curve of the cumulative number of the confirmed cases and the number of cured patients. Furthermore, we investigate the relationship between the suspected close contacts (SCC) and the final outcome of the growth trend of confirmed cases with a simulation approach.

Results: This article selects four representative countries, that is, China, South Korea, Italy, and the United States, and gives separate numerical simulations. The simulation results of the model fit the actual situation of the epidemic development and reasonable predictions are made. In addition, it is analyzed that the increasing number of SCC contributes to the epidemic outbreak and the prediction of the United States based on the population of the SCC highlights the importance of external intervention and active prevention measures.

Conclusions: The simulation of the model verifies its reliability and stresses that observable variable SCC can be taken as a pilot indicator of the coronavirus disease 2019 pandemic.