Persistence Infection of TGEV Promotes Enterococcus faecalis Infection on IPEC-J2 Cells.

Transmissible gastroenteritis virus (TGEV) is a coronavirus causing diarrhea with high incidence in swine herds. Its persistent infection might lead to epithelial-mesenchymal transition (EMT) of swine intestinal epithelial cells, followed by subsequent infections of other pathogens. Enterococcus faecalis (E. faecalis) is a member of the enteric microorganisms and an opportunistic pathogen. There is no report of secondary E. faecalis infection to TGEV, even though they both target to the intestinal tracts. To investigate the interactions between TGEV and E. faecalis, we set up an in vitro infection model by the swine IPEC-J2 cells. Dynamic changes of cell traits, including EMT and cell motility, were evaluated through qPCR, Western blot, electronic microscopy, scratch test, Transwell migration test and invasion test, respectively. The adhesion and invasion tests of E. faecalis were taken to verify the impact of the preceding TGEV infection. The cell morphology and molecular marker evaluation results showed that the TGEV persistent infection induced EMT on IPEC-J2 cells; increased cellular motility and invasion potential were also observed. Spontaneously, the expression levels of fibronectin (FN) and the membrane protein integrin-α5, which are dominant bacterial receptors on IPEC-J2 cells, were upgraded. It indicated that the bacteria E. faecalis adhered to IPEC-J2 cells through the FN receptor, and then invaded the cells by binding with the integrin-α5, suggesting that both molecules were critical for the adhesion and invasion of E. faecalis to IPEC-J2 cells. Additionally, it appeared that E. faecalis alone might trigger certain EMT phenomena, implying a vicious circle might occur. Generally, bacterial and viral co-infections are frustrating yet common in both human and veterinary medicines, and our observations on enteric TGEV and E. faecalis interactions, especially the diversity of bacterial invasion strategies, might provide new insights into the mechanisms of E. faecalis pathogenicity.

Association between early treatment with Qingfei Paidu decoction and favorable clinical outcomes in patients with COVID-19: A retrospective multicenter cohort study.

The coronavirus disease 2019 (COVID-19) epidemic has been almost controlled in China under a series of policies, including "early diagnosis and early treatment". This study aimed to explore the association between early treatment with Qingfei Paidu decoction (QFPDD) and favorable clinical outcomes. In this retrospective multicenter study, we included 782 patients (males, 56 %; median age 46) with confirmed COVID-19 from 54 hospitals in nine provinces of China, who were divided into four groups according to the treatment initiation time from the first date of onset of symptoms to the date of starting treatment with QFPDD. The primary outcome was time to recovery; days of viral shedding, duration of hospital stay, and course of the disease were also analyzed. Compared with treatment initiated after 3 weeks, early treatment with QFPDD after less than 1 week, 1-2 weeks, or 2-3 weeks had a higher likelihood of recovery, with adjusted hazard ratio (HR) (95 % confidence interval [CI]) of 3.81 (2.65-5.48), 2.63 (1.86-3.73), and 1.92 (1.34-2.75), respectively. The median course of the disease decreased from 34 days to 24 days, 21 days, and 18 days when treatment was administered early by a week (P < 0.0001). Treatment within a week was related to a decrease by 1-4 days in the median duration of hospital stay compared with late treatment (P<0.0001). In conclusion, early treatment with QFPDD may serve as an effective strategy in controlling the epidemic, as early treatment with QFPDD was associated with favorable outcomes, including faster recovery, shorter time to viral shedding, and a shorter duration of hospital stay. However, further multicenter, prospective studies with a larger sample size should be conducted to confirm the benefits of early treatment with QFPDD.