Identification of trypsin-degrading commensals in the large intestine.

Increased levels of proteases, such as trypsin, in the distal intestine have been implicated in intestinal pathological conditions1-3. However, the players and mechanisms that underlie protease regulation in the intestinal lumen have remained unclear. Here we show that Paraprevotella strains isolated from the faecal microbiome of healthy human donors are potent trypsin-degrading commensals. Mechanistically, Paraprevotella recruit trypsin to the bacterial surface through type IX secretion system-dependent polysaccharide-anchoring proteins to promote trypsin autolysis. Paraprevotella colonization protects IgA from trypsin degradation and enhances the effectiveness of oral vaccines against Citrobacter rodentium. Moreover, Paraprevotella colonization inhibits lethal infection with murine hepatitis virus-2, a mouse coronavirus that is dependent on trypsin and trypsin-like proteases for entry into host cells4,5. Consistently, carriage of putative genes involved in trypsin degradation in the gut microbiome was associated with reduced severity of diarrhoea in patients with SARS-CoV-2 infection. Thus, trypsin-degrading commensal colonization may contribute to the maintenance of intestinal homeostasis and protection from pathogen infection.

The Status of Pediatric Patients With Hematologic Malignancy During COVID-19 Pandemic in Wuhan City, China.

Data regarding the epidemiologic characteristics and clinical features of pediatric hematologic patients are limited in this corona virus disease 2019 (COVID-19) crisis. We investigated the status of 113 pediatric hematologic patients in Wuhan union hospital during the COVID-19 pandemic from January 23 to March 10, 2020. All the patients had routine blood and biochemical examination, as well as chest computed tomography scans, and the nucleic acid, immunoglobulin G-immunoglobulin M combined antibodies tests for SARS-CoV-2. After admission, all patients were single-room isolated for 5 to 7 days. The results showed that only 1 (0.88%) child with leukemia was confirmed to have SARS-CoV-2 infection and 15 (13.2%) children were considered as suspected cases. Comparing to the nonsuspected patients, the suspected cases had lower white blood cell count, hemoglobin level, neutrophil count, serum calcium ion level and serum albumin concentration, as well as higher levels of C-reactive protein. All the suspected cases were ruled out of SARS-CoV-2 infection by twice negative tests for the virus. Therefore, the incidence of SARS-CoV-2 infection in hematologic malignancy children was low during the COVID-19 pandemic in China. COVID-19 got early detected and the virus spread out in the ward was effectively blocked by increasing test frequency and using single-room isolation for 5 to 7 days after admission.

Clinical Characteristics of Children with Coronavirus Disease 2019 in Hubei, China.

Since December 2019, COVID-19 has occurred unexpectedly and emerged as a health problem worldwide. Despite the rapidly increasing number of cases in subsequent weeks, the clinical characteristics of pediatric cases are rarely described. A cross-sectional multicenter study was carried out in 10 hospitals across Hubei province. A total of 25 confirmed pediatric cases of COVID-19 were collected. The demographic data, epidemiological history, underlying diseases, clinical manifestations, laboratory and radiological data, treatments, and outcomes were analyzed. Of 25 hospitalized patients with COVID-19, the boy to girl ratio was 1.27:1. The median age was 3 years. COVID-19 cases in children aged <3 years, 3.6 years, and ≥6-years patients were 10 (40%), 6 (24%), and 9 (36%), respectively. The most common symptoms at onset of illness were fever (13 [52%]), and dry cough (11 [44%]). Chest CT images showed essential normal in 8 cases (33.3%), unilateral involvement of lungs in 5 cases (20.8%), and bilateral involvement in 11 cases (45.8%). Clinical diagnoses included upper respiratory tract infection (n=8), mild pneumonia (n=15), and critical cases (n=2). Two critical cases (8%) were given invasive mechanical ventilation, corticosteroids, and immunoglobulin. The symptoms in 24 (96%) of 25 patients were alleviated and one patient had been discharged. It was concluded that children were susceptible to COVID-19 like adults, while the clinical presentations and outcomes were more favorable in children. However, children less than 3 years old accounted for majority cases and critical cases lied in this age group, which demanded extra attentions during home caring and hospitalization treatment.