Objective:To investigate the molecular epidemiological characteristics of norovirus (NoV) in hospitalized children with sporadic acute gastroenteritis in Tianjin in 2019.Methods:Fecal specimens and clinical data were collected from 3 116 hospitalized children with sporadic acute gastroenteritis possibly caused by viral infection in Tianjin Children′ Hospital between January and December, 2019. Real-time quantitative PCR was used to detect NoV. Partial sequences of RNA-dependent RNA polymerase (RdRp) and capsid genes of NoV were amplified by RT-PCR. Sequence alignment and phylogenetic analysis were performed for further analysis.Results:Among the 3 116 specimens, 809 (26.0%) were positive for NoV. There were significant differences in NoV detection rate between different age groups ( P=0.000), and the highest NoV detection rate (31.6%) was observed in the age group of 7-12 months. Moreover, the detection rate of NoV varied with seasons ( P=0.000), and the NoV detection rate was highest in winter (39.0%). Based on the sequence analysis of RdRp and capsid genes, 286 identified NoV strains belonged to six genotypes, which were GⅡ.P12-GⅡ.3, GⅡ.P16-GⅡ.2, GⅡ.P17-GⅡ.17, GⅡ.Pe-GⅡ.2, GⅡ.Pe-GⅡ.3 and GⅡ.Pe-GⅡ.4. The predominant genotype was GⅡ.Pe-GⅡ.4 Sydney 2012 (61.2%), followed by GⅡ.P12-GⅡ.3 (33.6%, 96/286), GⅡ.Pe-GⅡ.3 (2.4%, 7/286), GⅡ.P16-GⅡ.2 (2.1%, 6/286), GⅡ.Pe-GⅡ.2 (0.3%, 1/286) and GⅡ.P17-GⅡ.17 (0.3%, 1/286). Patients carrying the NoV of GⅡ.Pe-GⅡ.4 Sydney 2012 genotype were likely to suffer from vomiting than those positive for NoV of GⅡ.P12-GⅡ.3 genotype. Conclusions:NoV was an important pathogen causing acute gastroenteritis in children. GⅡ.Pe-GⅡ.4 Sydney 2012 and GⅡ.P12-GⅡ.3 were the major genotypes of NoV in hospitalized children with sporadic acute gastroenteritis in Tianjin in 2019.

Objective:To evaluate the prevalence of human rhinovirus (HRV) infection in hospitalized children in Tianjin and investigate the clinical impact of HRV infections.Methods:From July 2017 to December 2019, 2 945 nasopharyngeal secretion specimens were screened for HRV using polymerase chain reaction (PCR). VP4/VP2 sequences of HRV were further characterized. The clinical characteristics of the HRV infection were analyzed. The detection results of HRV for different groups and different months were compared using SPSS 19.0.Results:HRV-positive specimens accounted for 8.15% (240/2 945), of which 74.78% (86/115) were diagnosed with pneumonia, 40.83%(98/240) had co-infections with other common pathogens. HRV infections could be detected throughout the year with peaks in spring (11.00%, 66/660) and autumn (9.29%, 81/872). The positive rate of HRV was 4.14%(29/700) in winter. By VP4/VP2 sequence analysis, HRV-A was the most frequently detected strain(50.00%, 78/156), followed by HRV-C (41.67%, 65/156).46.15% (30/65) of HRV-C infections occurred in October and November. There were several different HRV-A types and HRV-C types. The most commonly detected HRV-A types were A12(11.54%, 9/78), A49(6.41%, 5/78), A22, A101, and A66(5.13%, 4/78), etc. The most common HRV-C types were C2(20.00%, 13/65), C22(9.23%, 6/65), C26, C43, C54 and C53(4.62%,3/65). Patients with HRV-A infections are more likely to show fever symptoms than HRV-C (χ2=5.411, P<0.05). No significant difference in other symptoms were found between the two types. Conclusions:HRV was a commonly detected virus among infants and had a clear seasonal distribution. It′s also possible for the HRV patients to have co-infections with other pathogens.HRV showed high genetic diversity.

Objective:To investigate the prevalence and clinical characteristics of Mycoplasma pneumoniae( Mp) genotypes and subtypes in children in Tianjin. Methods:Children with pneumonia admitted to Tianjin Children′s Hospital from December 2017 to December 2019 were selected as the research objects. Bronchoalveolar lavage fluid was collected by fiberoptic bronchoscopy. The positive samples were detected by real-time fluorescent quantitative PCR and Mp culture. PCR-restriction fragment length polymorphism(RFLP) and multiple variable number tandem repeats were used for genotyping. Detailed clinical and laboratory data were collected for all cases. Results:The results of RFLP showed that there were 138 cases (78.9%) of typeⅠand 37 cases (21.1%) of type Ⅱ; 37 cases of type M3-5-6-2, including six subtypes B, G, M, S, V and Y; 138 cases of M4-5-7-2 were detected, including seven subtypes of E, J, P, U, X, Z and a. In M3-5-6-2 type, there were 1 case of P1-Ⅰtype (2.7%), 36 cases of P1-Ⅱtype (97.3%), 137 cases of P1-Ⅰ type (99.2%) and 1 case of P1-Ⅱ type (0.7%) in M4-5-7-2 type. There was no significant difference in genotype distribution among different age groups. There were statistical differences in the distribution of four seasons among the 13 genotypes of B, G, M, S, V, Y and E, J, P, U, X, Z, a. All Mp infected children had symptoms of fever and cough. The hospitalization time, fever duration, high fever (>39℃), cough duration, skin changes, digestive system symptoms and liver function injury rate of P1-Ⅰ/M4-5-7-2 pneumonia children were higher than those of P1-Ⅱ/M3-5-6-2 pneumonia children, but the difference was not statistically significant. The WBC count of P1-Ⅱ/M3-5-6-2 types was higher than that of typeⅠand M4-5-7-2; the LDH of P1-Ⅰ/M4-5-7-2 was higher than that of Ⅱ and M3-5-6-2, with statistical difference. There was no significant difference in the incidence of inflammatory consolidation, atelectasis, pleural thickening and pleural effusion among different genotypes. Conclusions:Mp infection in children with pneumonia in Tianjin is mainly P1-Ⅰ/ M4-5-7-2, and P1-Ⅱ is on the rise. P1-Ⅰ and M4-5-7-2 were associated with fever and severe symptoms.

Objective:To understand the pathogen infection and epidemiological characteristics of children with diarrhea in Tianjin.Methods:Stool samples from 1 466 children with diarrhea in Tianjin Children's Hospital from August 2017 to July 2018 were collected, and all samples were tested for five intestinal-related pathogens (norovirus, rotavirus, Clostridium difficile toxin, adenovirus, and astrovirus). Results:Among the 1 466 samples, 627 samples were positive for nucleic acid detection of intestinal pathogens, with a positive rate of 42.8%. The detection rate of norovirus was the highest (26.3%), followed by rotavirus (15.3%), Clostridium difficile toxin (4.6%), adenovirus (4.1%), and astrovirus (1.84%). The infection has obvious seasonality. The positive detection rates of the five pathogens were similar among children of different sexes, and only the positive detection rates of norovirus and rotavirus were statistically significant among different ages ( P<0.05). There were 110 cases of mixed infection, and the mixed infection of norovirus and rotavirus was the most common, with a total of 37 cases. Conclusions:The pathogen spectrum of infant infectious diarrhea in Tianjin is complex and diverse, and the main pathogens are norovirus and rotavirus.

Objective:To analyze the molecular epidemiological characteristics of GⅡNorovirus (NoV) infection in children in Tianjin Children′s Hospital in 2018.Methods:Single center study. From January to December 2018, a total of 2 185 stool specimens were collected from the children with acute gastroenteritis suspected caused by virus infection in Tianjin Children′s Hospital. Norovirus was detected by real-time fluorescence reverse transcription polymerase chain reaction (RT-PCR).The capsid protein VP1(VP1) region of positive samples was amplified and sequenced. The phylogenetic tree was constructed by MEGA5.05 for analyzing the results. The detection of NoV in different age groups and different months were compared by SPSS 20.0.Results:Among the 2 185 stool specimens,610 were NoV positive, the positive rate was 27.9% (610/2 185).All of the positive samples were GⅡgenogroup. Seven genotypes were found, with GⅡ.3 subtype accounting for 46.2%(151/327),GⅡ.4 subtype accounting for 40.1%(131/327),GⅡ.2 subtype accounting for 4.6%(15/327), other subtypes accounting for 9.1%(30/327).There was a significant difference in NoV detection rate among different age groups (χ 2=17.050, P=0.002). Among the positive specimens, the detection rate of less than or equal to 3 years old was the highest which is accounting for 89.2%.Also there was a significant difference in NoV detection rate among different months(χ 2=225.153, P<0.001).November and December are the most frequent months. There was significant difference between GⅡ.3 and GⅡ.4 NoV infection in children with granulocytopenia (χ 2=11.270, P=0.001) , and also in children with respiratory symptoms (χ 2=7.257, P=0.007) . Conclusions:GⅡ.3 and GⅡ.4 were the main genotypes of NoV infection in children in Tianjin in 2018. The Multiple genotypes suggests that the monitoring and prevention of NoV infection in children should continue to be strengthened in the future.

Objective:To describe a series of systemic sclerosis (SSc) patients with the combination of scleroderma renal crisis (SRC) and pulmonary arterial hypertension (PAH).Methods:The medical records of 472 SSc patients in Peking Union Medical College Hospital between January 2012 and October 2020 were reviewed and a retrospective analysis of the characteristics of patients with SRC and PAH among SSc patients was conducted.Results:Thirteen patients suffered from SRC and PAH in the SSc patients, 1 case was limited cutaneous SSc, and 12 cases were diffuse cutaneous SSc. Five patients had renal crisis before pulmonary arterial hypertension, 4 patients had pulmonary arterial hypertension before the occurrence of renal crisis, and the remaining 4 patients were found at the same time. Among them, 11 patients had Raynaud's phenomenon, 7 had gastrointestinal bleeding, 6 had pulmonary edema and 3 had telangiectasias. Twelve cases were positive for anti-nuclear antibodies and 4 cases were positive for anti-Scl-70 antibodies. N-terminal pro-brain natriuretic peptide (NT-proBNP)>1 400 ng/L in 11 patients. Two patients had thrombotic microangiopathy (TMA). Among the 13 patients, 3 patients died during hospitalization, 2 patients were lost to follow-up, and 2 patients died within 5 years of follow-up. Six patients survived, and 1 of the 4 patients with regular dialysis were discharged from dialysis.Conclusion:In patients with scleroderma, SRC can occur earlier, later than, or at the same time with SSc-PAH. Patients may have a higher incidence of gastrointestinal bleeding and higher level of NT-proBNP. PDE5i or ERAs may be beneficial.