Objective To explore the diagnostic value of capsule endoscopy and small bowel CT virtual endoscopy( CTVE) in identifying of small intestinal diseases. Methods Fifty?five cases patients of suspected small intestinal diseases who were treated by Capsule endoscopy and small bowel CTVE examination in the Affili?ated Hospital of North China University of Science&Technology and Kailuan Majiagou Mine Hospital from Janu?ary 2009 to December 2015 were chosen. The detection rate and diagnostic accuracy of small bowel disease were compared between the two methods. Results There was no significant difference in the detection rate of CTVE and capsule endoscopy( 80. 7% vs. 89. 5%,P=0. 719) . There was significant difference in the accuracy of CTVE and capsule endoscopy in the diagnosis of small intestinal non space occupying lesions ( 60. 7% vs. 89. 3%, P=0. 040) . The correct rate of diagnosis of small bowel lesions was 93. 1% in CTVE,and 51. 7% in capsule en?doscopy,there was statistically significant difference between the two ways( P=0. 032) . Conclusion Capsule endoscopy and CTVE are both non invasive tests,the operation is simple,safe,and the patients are easy to ac?cept,and they are both helpful in the diagnosis of small bowel diseases. Capsule endoscopy has an advantage in the diagnosis of small bowel lesions,while CTVE is superior to capsule endoscopy in terms of small bowel occup?ying lesions. Combined use of the two ways can improve the diagnostic rate of small bowel disease.

Objective:To understand the molecular characteristics of the mutant strain of polymerase basic protein 2 (PB2) gene of influenza A (H1N1pdm) in Guangdong province, and to explore its specific molecular sites, so as to provide scientific basis for the prevention and control of influenza virus.Methods:Throat swab samples were collected from 2 cases infected with PB2 gene variant strains for virus isolation, and 23 influenza virus strains were selected from Guangdong province for sequencing analysis. The reference sequences and vaccine strain sequences provided by GISAID were used to perform evolutionary analysis on hemagglutinin (HA) and PB2 genes. Virus strain antigen analysis and neuraminidase (NA) inhibition test were carried out. PB2 protein model was constructed and polymerase activity was analyzed.Results:H399N amino acid mutation occurred in the HA gene of PB2-D701N and PB2-A271S variant strains, both of which belonged to the branch of 6B.1A.5a.2a. They belonged to the same big branch and different small branches as the vaccine strain A/Victoria/4897/2022, and they are all vaccine-like strains. In the three-dimensional structure, the mutations of PB2-D701N and PB2-A271S change charge and hydrophobicity.Conclusions:PB2-D701 and A271 were highly conserved, and PB2 mutant strains were not the dominant strains. The PB2 mutant had high antigenicity with the vaccine. The PB2 mutant strain is sensitive to NA inhibitors. The three-dimensional model predicted that PB2-D701N mutation could enhance virulence and affect transmissibility of influenza virus, while PB2-A271S mutation could affect polymerase activity and polymerase complex synthesis of influenza virus.

Objective:To detect the pathogen and clinically diagnose for a suspected case of Neisseria meningitidis with positive blood culture result, and assess the risk of disease transmission among the community. Methods:Blood sample was collected for Neisseria meningitidis isolation and culture. Pathogen identification and serogroup typing were conducted by colony morphology, Gram staining, biochemical tests, latex agglutination test, slide agglutination test, and nucleic acid testing. The susceptibility to 12 antibiotics was also tested. Epidemiological investigation was conducted on the case, and epidemic control measures were also implemented. Results:Through various detection, the suspected case was diagnosed as Neisseria meningitidis invasive infection. The isolated strain belonged to group Y serotype, type 767 (multilocus sequence typing), and the ST167 clonal complex. The strain was sensitive to nine antibiotics, including penicillin, ampicillin, and meropenem. It exhibited intermediate sensitivity to ciprofloxacin and levofloxacin, and resistance to methicillin/sulfamethoxazole. Close contacts of the case and environmental testing results were negative. Conclusions:The case is confirmed to be an invasive infection caused by group Y Neisseria meningitidis, the ST167 clonal complex. Epidemiological investigation shows a relatively low risk of epidemic transmission. Continuous monitoring and surveillance are necessary for further assessment.

Objective:To understand the genetic variation and epidemiological characteristics of human respiratory syncytial virus (HRSV) in Guangzhou.Methods:Nasopharyngeal swabs specimens were collected from 0-6 year old children hospitalized with acute respiratory infection, then HRSV was tested and genotyped by RT-PCR. Phylogenetic tree was bulit using MEGA 6.0 software. NetNGlyc 1.0 server was used to predict the potential N-linked glycosylation sites.Results:A total of 1 225 nasopharyngeal specimens were collected, including 783 males and 442 females. The median ( P25, P75) age was 8 (3, 24) months. Among the 209 HRSV-positive cases (17.06%), 117 cases (55.98%) were HRSV-A and 92 cases (44.02%) were HRSV-B. The two distinct subgroups (HRSV-A and HRSV-B) alternately played dominant role to cause HRSV infection and exchange almost once every two years. The HRSV prevalence rate decreased with age. The HRSV-positive rate among children under 2 years old was 18.83% (196 cases), accounting for 93.78% of the total positive cases. There were 32 HRSV positive cases co-infected with at least one respiratory virus, with the co-infection rate of 15.31%. Phylogenetic tree analysis of the second hypervariable region (HVR2) of the G protein classified the HRSV-A specimens into ON1 ( n=62) and NA1 ( n=2) genotypes while all HRSV-B specimens belonged to BA genotype ( n=53). The HVR2 of the G protein varied in using stop condon, amino acid substitutions, glycosylation sites. Conclusion:Children under 2 years old were the high risk population of HRSV infection in Guangzhou. ON1 genotype turned into a primary genetype of the HRSV-A subgroup while BA genotype dominated the HRSV-B subgroup. A greater diversification of amino acid substitutions, and some deletion and insertion of glycosylation sites embodied the polymorphism of G protein as main protective antigen.

Objective:To understand the genetic variation and epidemiological characteristics of human respiratory syncytial virus (HRSV) in Guangzhou.Methods:Nasopharyngeal swabs specimens were collected from 0-6 year old children hospitalized with acute respiratory infection, then HRSV was tested and genotyped by RT-PCR. Phylogenetic tree was bulit using MEGA 6.0 software. NetNGlyc 1.0 server was used to predict the potential N-linked glycosylation sites.Results:A total of 1 225 nasopharyngeal specimens were collected, including 783 males and 442 females. The median ( P25, P75) age was 8 (3, 24) months. Among the 209 HRSV-positive cases (17.06%), 117 cases (55.98%) were HRSV-A and 92 cases (44.02%) were HRSV-B. The two distinct subgroups (HRSV-A and HRSV-B) alternately played dominant role to cause HRSV infection and exchange almost once every two years. The HRSV prevalence rate decreased with age. The HRSV-positive rate among children under 2 years old was 18.83% (196 cases), accounting for 93.78% of the total positive cases. There were 32 HRSV positive cases co-infected with at least one respiratory virus, with the co-infection rate of 15.31%. Phylogenetic tree analysis of the second hypervariable region (HVR2) of the G protein classified the HRSV-A specimens into ON1 ( n=62) and NA1 ( n=2) genotypes while all HRSV-B specimens belonged to BA genotype ( n=53). The HVR2 of the G protein varied in using stop condon, amino acid substitutions, glycosylation sites. Conclusion:Children under 2 years old were the high risk population of HRSV infection in Guangzhou. ON1 genotype turned into a primary genetype of the HRSV-A subgroup while BA genotype dominated the HRSV-B subgroup. A greater diversification of amino acid substitutions, and some deletion and insertion of glycosylation sites embodied the polymorphism of G protein as main protective antigen.

Objective:To analyze and reveal the genetic evolution and variation of influenza viruses in cases of co-infection in Guangdong Province.Methods:Throat swab samples were collected from four cases of H1N1pdm and H3N2 co-infection for viral isolation. The isolated strains were subjected to antigen analysis and neuraminidase inhibitor susceptibility test. High-throughput sequencing was used to detect the sequences of strains in three throat swab samples and one virus strain, and then genetic variations were analyzed.Results:Four influenza viruses were isolated with one strain of H1N1pdm and three of H3N2 subtype, and all of them were genetically similar to the vaccine strain in 2022-2023. The HA genes of H1N1pdm and H3N2 strains belonged to clade 6B.1A.5a.2a and 2a.3a.1, respectively. The isolated strains belonged to the same clade as the strains prevalent in Guangdong during the same period. No drug-resistant variations were detected in N1 or N2 gene, and the isolated strains were sensitive to oseltamivir and zanamivir.Conclusions:H1pdm subtype had stronger replication ability than H3 subtype in the influenza viruses isolated from co-infected cases. H1N1pdm and H3N2 subtype influenza viruses were genetically similar to the strains circulating in Guangdong at the same time. The isolated H1N1pdm and H3N2 strains were sensitive to both oseltamivir and zanamivir, indicating that they could continue to be used in the treatment of influenza virus infections caused by one or two genotypes.

Objective:To obtain the genome sequences of SARS-CoV-2 in respiratory specimens in Guangdong Province with next-generation sequencing (NGS) and analyze the factors influencing sequencing.Methods:Eight upper and lower respiratory tract specimens were collected from patients with SARS-CoV-2 infection in Guangdong Province in January 2020. RNA library construction was used to obtain the genome sequences of SARS-CoV-2. A bio-informatics software package (CLC Genomics Workbench 12.0) was used to analyze and compare the genomic sequences.Results:Five SARS-CoV-2 genome sequences were obtained from the eight specimens and two were obtained from lower respiratory tract specimens. The nucleotide homology to SARS-CoV-2 was 97.74%-99.90%. The Ct values were lower, while the sequencing depth, coverage, relative abundance and genome integrity were higher in sequencing the SARS-CoV-2 in lower respiratory tract specimens.Conclusions:The low Ct value of SARS-CoV-2 in the samples was good for sequencing.