Effect of rifaximin on gut-lung axis in mice infected with influenza A virus.

Gut-lung axis injury is a common finding in patients with respiratory diseases as well as in animal model of influenza virus infection. Influenza virus damages the intestinal microecology while affecting the lungs. Rifaximin, a non-absorbable derivative of rifamycin, is an effective antibiotic that acts by inhibiting bacterial RNA synthesis. This study aimed to determine whether rifaximin-perturbation of the intestinal microbiome leads to protective effects against influenza infection, via the gut-lung axis. Our results showed that influenza virus infection caused inflammation of and damage to the lungs. The expression of tight junction proteins in the lung and colon of H1N1 infected mice decreased significantly, attesting that the barrier structure of the lung and colon was damaged. Due to this perturbation in the gut-lung axis, the intestinal microbiota became imbalanced as Escherichia coli bacteria replicated opportunistically, causing intestinal injury. When influenza infection was treated with rifamixin, qPCR results from the gut showed significant increases in Lactobacillus and Bifidobacterium populations, while Escherichia coli populations markedly decreased. Furthermore, pathology sections and western blotting results illustrated that rifaximin treatment strengthened the physical barriers of the lung-gut axis through increased expression of tight junction protein in the colon and lungs. These results indicated that rifaximin ameliorated lung and intestine injury induced by influenza virus infection. The mechanisms identified were the regulation of gut flora balance and intestinal and lung permeability, which might be related to the regulation of the gut-lung axis. Rifaximin might be useful as a co-treatment drug for the prevention of influenza virus infection.

Epidemiological characteristics of COVID-19 clusters in Nanning / 预防医学

Objective@#To learn the epidemiological characteristics of coronavirus disease 2019(COVID-19)clusters in Nanning,Guangxi Province,so as to provide reference for the prevention and control of COVID-19. @*Methods@#The data of COVID-19 clusters from January to February,2020 in Nanning were collected through the Public Emergency Response System of National CDC. Descriptive epidemiological analysis were conducted to analyze the time,space and population distribution, source of infection,transmission chain, ways of detection and the scale of clusters. @*Results@#Eleven clusters were reported,with 36 confirmed cases and 293 exposed persons. The average attack rate was 12.29%. There were ten family clusters. The epidemic scale was small,with an average of 3.27 cases. The onset of cases peaked on January 23,while the reporting time was mainly from February 10 to February 18. The cases were distributed in two cities and one county. The attack rate of Qingxiu District and Xixiangtang District was 16.95%,which was higher than 5.17% of Mashan County(p<0.05). The recurrence rate of family contacts was 25.42%,which was higher than that of other ways of contacts(p<0.05). Of eleven clusters,nine were caused by imported cases or related cases;five developed secondary cases or above,and the median interval between the first and secondary cases was three days.@*Conclusions@#The COVID-19 clusters in Nanning occurred mainly in families with small scales and most were caused by imported cases. The majority of the cases were reported during mid February. The attack rate in urban areas was higher than that in rural areas.