Objective:To investigate the pathogenetic characteristics of clinical isolates of Streptococcus suis in Henan Province from 2020 to 2023. Methods:Eight clinical isolates of S. suis in Henan Province from 2020 to 2023 were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and real-time fluorescence polymerase chain reaction (PCR). Serotype and virulence genes were detected by the serum agglutination test and PCR, and antibiotic susceptibility was evaluated using the microbroth dilution method. Multilocus sequence typing (MLST), minimum core genome (MCG), identification of antibiotic resistance genes, and core genome single nucleotide polymorphism (cgSNP) analysis were conducted using whole genome sequencing. Results:The results showed that eight S. suis strains isolated from humans were mainly serotype 2 (75.0%), while the rest were serotype 14 (25.0%). ST353 (62.5%) was the predominant genotype, followed by ST1 (25.0%) and ST7 (12.5%). All isolates belonged to the MCG1 group. The virulence genotypes of these isolates were primarily mrp(NA2)/ sly+/ ef+/ gapdh+(75.0%), while the remaining were mrp(EU)/ sly+/ ef+/ gapdh+(25.0%). These isolates carried tetracycline, macrolide, lincosamide and aminoglycoside resistance genes, and their resistance rates to tetracycline, erythromycin and clindamycin were 100.0%, 87.5% and 87.5%, respectively, and 62.5% strains were intermediate-resistant to penicillin. The cgSNP analysis indicated that these isolates were closer to the isolates from Guangdong, Zhejiang and Guangxi Provinces, with five ST353 strains and one ST7 strain belonging to Clade Ⅰ, and two ST1 strains belonging to Clade Ⅱ. Conclusion:The human isolates of S. suis in Henan Province are mainly ST353, harboring multiple virulence and antibiotic resistance genes.

Objective:To investigate the pathogenetic characteristics of clinical isolates of Streptococcus suis in Henan Province from 2020 to 2023. Methods:Eight clinical isolates of S. suis in Henan Province from 2020 to 2023 were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and real-time fluorescence polymerase chain reaction (PCR). Serotype and virulence genes were detected by the serum agglutination test and PCR, and antibiotic susceptibility was evaluated using the microbroth dilution method. Multilocus sequence typing (MLST), minimum core genome (MCG), identification of antibiotic resistance genes, and core genome single nucleotide polymorphism (cgSNP) analysis were conducted using whole genome sequencing. Results:The results showed that eight S. suis strains isolated from humans were mainly serotype 2 (75.0%), while the rest were serotype 14 (25.0%). ST353 (62.5%) was the predominant genotype, followed by ST1 (25.0%) and ST7 (12.5%). All isolates belonged to the MCG1 group. The virulence genotypes of these isolates were primarily mrp(NA2)/ sly+/ ef+/ gapdh+(75.0%), while the remaining were mrp(EU)/ sly+/ ef+/ gapdh+(25.0%). These isolates carried tetracycline, macrolide, lincosamide and aminoglycoside resistance genes, and their resistance rates to tetracycline, erythromycin and clindamycin were 100.0%, 87.5% and 87.5%, respectively, and 62.5% strains were intermediate-resistant to penicillin. The cgSNP analysis indicated that these isolates were closer to the isolates from Guangdong, Zhejiang and Guangxi Provinces, with five ST353 strains and one ST7 strain belonging to Clade Ⅰ, and two ST1 strains belonging to Clade Ⅱ. Conclusion:The human isolates of S. suis in Henan Province are mainly ST353, harboring multiple virulence and antibiotic resistance genes.

Objective:To analyze the specific immunoglobulin G (IgG) antibodies level in the population after the coronavirus disease 2019 (COVID-19) pandemic in Henan Province.Methods:A total of 5 178 peripheral venous blood samples were collected from 10 districts (counties) in Henan Province according to the national seroepidemiological survey program for COVID-19, and the method of cluster random sampling was adopted from March 6 to 15, 2023. Descriptive analysis was used for the basic data, history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, SARS-CoV-2 infection of the respondents. The specific IgG antibody of SARS-CoV-2 was detected using chemiluminescence method. Statistical analysis was performed by using rank sum test, Kruskal Wallis test, and Dunn′s test.Results:The overall positive rate of SARS-CoV-2-specific IgG antibody was 83.35%(4 316/5 178). There were statistically significant differences in the specific IgG antibodies against SARS-CoV-2 produced by people of different sexes, different ages, infected or not, vaccinated or not, and vaccinated with different doses of SARS-CoV-2 vaccine ( Z=3.60, H=195.32, Z=6.10, 18.08, H=382.70, respectively, all P<0.001). The specific IgG antibodies produced by unvaccinated+ uninfected group, unvaccinated+ infected group, vaccinated+ uninfected group, and vaccinated+ infected group were 3.54(0.98, 11.00), 60.65(2.33, 84.80), 133.00(59.80, 173.00), and 142.00(98.30, 176.00), respectively. And the difference was statistically significant( H=354.62, P<0.001). The specific IgG antibodies of uninfected people increased with the increase of inoculum times( H=287.00 and 98.48, both P<0.001). The specific IgG antibodies of people who were not infected with SARS-CoV-2 in the groups of whose interval from the last inoculation of SARS-CoV-2 vaccine to blood collection was less than three months, three to six months and more than six months were 171.86(156.04, 196.57), 71.71(17.08, 110.38) and 132.14(57.59, 172.25), respectively, and the difference was statistically significant ( H=19.93, P<0.001). Among them, the absolute difference between the less than three months group and the three to six months group was statistically significant ( Z=3.67, P<0.001), and the absolute difference between the less than three months group and the more than six months group was statistically significant ( Z=3.47, P<0.001). The specific IgG antibodies level in the less than three months group was the highest. Conclusions:There is a certain correlation between the number of SARS-CoV-2 vaccine doses and the specific IgG antibodies level in uninfected people. The specific IgG antibodies could maintain a high level for three months after immunization.

Objective:To monitor the changes in specific IgM and IgG antibodies in patients diagnosed with COVID-19 after SARS-CoV-2 infection, and analyze their clinical significance.Methods:A total of 168 serum samples were collected from 56 COVID-19 patients with different disease courses who were positive for nucleic acid test at Henan Center for Disease Control and Prevention on January 8, 2020 and February 21, 2020. Serum samples from 25 healthy people excluded from COVID-19 were used as control group. IgM and IgG antibodies against SARS-CoV-2 were detected by chemiluminescence method.Results:IgM antibody increased sharply in 1-3 weeks after onset, and reached the peak value (21.78 AU/ml) in the 3rd week after onset. IgG antibody increased the most in 3-6 weeks after onset, and reached the peak value (81.58 AU/ml) in the 9th week after onset. The levels of IgM and IgG antibodies were closely correlated with age and disease course ( P<0.05). The antibody level of 30-60 years old group was the highest, the IgM antibody positive rate and antibody level of acute stage and previous infection were lower than that of recovery stage, and the IgG antibody positive rate and antibody level of acute stage were lower than that of recovery stage and previous infection. During the whole course of the disease, the levels of IgM and IgG antibodies increased gradually in the acute stage, reached the peak in the recovery stage, and decreased and maintained at a certain level in the past infection. Conclusions:Serum SARS-CoV-2 IgM and IgG antibody detection can be used as auxiliary diagnostic indicators for COVID-19, and its continuous observation is helpful for epidemiological investigation, serological diagnosis and disease course monitoring.

Objective:To investigate the etiological characteristics and drug resistance of non-typhoid Salmonella isolated from stool samples of children under 5 years old with diarrhea in Henan Province. Methods:Intestinal bacteria were isolated from fecal samples of 4 250 diarrhea children under five years old in five monitoring sites in Henan Province from 2015 to 2018. Serotypes and drug sensitivity of Salmonella strains were analyzed. The annual change in drug resistance was analyzed by Chi-square test and all data were analyzed retrospectively. Results:The detection rate of non-typhoid Salmonella in fecal samples was 8.73% (371/4 250). The highest detection rate was in the 0-1 age group (51.75%) and the peak season for Salmonella infection was from May to October. The most common serotype was Salmonella enteritidis (36.93%), followed by 4, 5, 12: i: - Salmonella (14.82%) and Salmonella typhimurium (14.02%). The non-typhoid Salmonella isolates were resistant to ampicillin and sulfamethoxazole with drug resistance rates of more than 80%, but more sensitive to ceftazidime, cefepime and cefoxitin. There were significant differences in drug resistance to cefepime, levofloxacin, ciprofloxacin, amikacin, doxycycline, chloramphenicol and compound neoforman among the strains isolated in different years ( P<0.05). Multidrug-resistant strains accounted for 86.52%. Conclusions:There was diversity in the serotypes of non-typhoid Salmonella in diarrheal children under five years old in Henan Province. The predominant serotype was Salmonella enteritidis. Drug resistance to common antibiotics was detected in the isolates, and most of them were multidrug-resistant.

Objective:To explore the serotype distribution and drug resistance of Shigella in stool samples of children under five years old with diarrhea from 2008 to 2017 in Sui County, Henan Province. Methods:A total of 4 721 stool samples of children under five years old with diarrhea were collected from Doufuyuan Clinic of Sui County during 2008 to 2017, and Shigella strains were isolated through bacterial culture. The slide agglutination test was used for serotyping of Shigella strains. Two hundred of seventy-one Shigella strains were selected in proportion, and multiple gradient polymerase chain reaction was used to detect virulence genes and Kirby-Bauer agar method was used for drug sensitivity. Trend chi square test was used to analyze the annual trend of drug resistance. Results:The detection rate of Shigella strains in 4 721 fecal samples was 20.69% (977/4 721). A total of 977 Shigella strains were divided into 13 serotypes in two groups, including 77.79%(760/977) Shigella flexneri strains and 22.21%(217/977) Shigella sonnei strains.The top three serotypes detected alternately every year.The dominant gene pattern of Shigella flexneri was Shigella enterotoxin ( shET)-1+ , shET-2+ , invasion plasmid antigen H ( ipaH)+ , invasion-associated locus ( ial)+ , accounted for 84.04%(179/213) and that of Shigella sonnei was shET-1-, shET-2+ , ipaH+ , ial+ , accounted for 46.55%(27/58). The drug resistance rates of 271 Shigella strains to ampicillin, nalidixic acid and tetracycline were more than 90% and the strains were more sensitive to cefepime and ceftazidime.The drug resistance rates to cefotaxime, cefepime, ciprofloxacin, chloramphenicol and sulfamethoxazole/trimethoprim increased year by year, and all had statistically significant differences ( χ2=24.027, 7.232, 6.039, 4.764 and 6.809, respectively, all P< 0.05). There were 98.52%(267/271) strains resistant to more than three kinds of drugs. The resistance rates of Shigella flexneri to ciprofloxacin, norfloxacin, and chloramphenicol were higher than those of Shigella sonnei, and the resistance rates to gentamicin and sulfamethoxazole/trimethoprim were lower than those of Shigella sonnei. The differences were statistically significant ( χ2=31.866, 14.868, 83.036, 68.534 and 14.738, respectively, all P<0.01). Conclusions:The major serotypes of Shigella in children under five years old in Sui County are constantly changing from 2008 to 2017. The dominant gene patterns of different serotypes are different. Most isolated strains have multiple drug resistances, and different serotypes have different resistance profiles.

Objective To investigate the distribution and etiological characteristics of Yersinia en-terocolitica in Henan province between 2011 and 2017 and to analyze the homology among pathogenic strains. Methods A total of 12728 samples, including stool specimens from patients with diarrhea and domestic animals, flies, and smear specimens from raw and cooked meat products, were collected. Cold enrichment method was used to isolate Yersinia enterocolitica. The isolated strains were analyzed by biochemical identifi-cation, biotyping, serotyping and virulence gene detection with PCR. Pulsed-field gel electrophoresis ( PFGE) was performed for molecular typing of pathogenic strains. Results There were 390 strains of Yersinia enterocolitica isolated from the 12728 specimens with a detection rate of 3. 06％, including 13 hu-man strains and 377 animal strains. Most of the strains were isolated from pig and chicken feces and both ac-counted for 25. 13％ (98/390). The predominant biotype was 1A and the serotypes of the strains were main-ly O : 5 and O : 8. Results of the virulence gene analysis showed that 21 strains of O : 3 serotype were path-ogenic, including one human strain and 20 pig strains. After NotⅠdigestion, these pathogenic strains were divided into three band types with a band similarity of 94％-100％. Conclusions Yersinia enterocolitica ex-isted in both human population and many kinds of animals in Henan province. Pig was the main host of path-ogenic strains and there was a high homology among these strains.

Objective To investigate the etiological,antimicrobial resistance status and pulsed field gel electrophoresis (PFGE) patterns of S.enteritidis strains in Henan Province.Methods Totally 82 strains of S.enteritidis strains were isolated from seven sentiel hospitals which were able to detect multiple pathogens from April,2013 to December,2015.According to Salmonella K-B drug susceptibility testing and molecular typing method published by the USA clinical and Laboratory Standards Institute (2015),the drug sensitivity to 7 kinds of antimicrobial agents and PFGE molecule characteristics of 82 S.enteritidis strains were tested.The PFGE patterns were analyzed by BioNumerics 6.0 software based on international PulseNet bacterial infectious disease monitoring network.Results Forty-seven strains of S.enteritidis were isolated from male patients,35 strains isolated from female patients.A total of 56 S.enteritidis strains were isolated from young children aged from 0 to 5 years old,including 29 strains isolated from 6 months to 2 years old.The strains were mainly isolated between May and November of the year,and 15 (18.3％) strains were isolated between March and April,27(32.9％) strains between May and July,34 (41.5％) strains between August and October,6 (7.3％) strains were isolated in the rest time of the year,with a typical seasonal characteristics of summer and autumn.Sxity-four (78.0％)strains of S.enteritidis were resistant to ampicillin;23 (28.0％) strains were resistant to ceftazidime;39 (47.6％) strains were resistant to cefotaxime:13 (15.9％) strains were resistant to cefepime;55 (67.1％) strains were resistant to nalidixic acid;24 (29.3％) strains were resistant to ciprofloxacin;32 (39.0 ％) strains were resistant to gentamicin;14 (17.1 ％) strains were resistant to chloramphenicol;47 (57.3％) strains were resistant to methicillin benzyl ammonium;13 (15.9％) strains were resistant to sulfamethoxazole and trimethoprim;21 (25.6 ％) strains were resistant to tetracycline.All strains weremuhi-drug resistant,and 21 (25.6％) isolates were resistant to 3-4 kinds of antibiotics,32 (39.0％)isolates were resistant to 5-6 kinds of antibiotics, 29 (35.4 ％) isolates were resistant to 7-8 kinds ofantibiotics.These 82 strains of S.enteritidis were divided into 25 molecular patterns by digestion withXba Ⅰ enzyme.Each pattern contained 1 to 26 strains with similarity ranged from 59.33％-100.00％.EN1 and EN2 were the main PFGE belt types and included 26 and 16 strains,respectively.Conclusions The drug resistance of clinical isolates of S.enteritidis in Henan province is serious.PFGE patterns show polymorphism and the dominant patterns,part of which are associated with drug-resistance spectrum and show aggregation.

Objective: To investigate the infectious status, gene type transition and epidemiological features of rotavirus A isolated from infants and children (<59 months-of-age) in sentinel hospitals from 2008 to 2015 in Henan province, China. Methods: In total, 2 541 stool samples (each 3- 5 ml) were collected from infants and children aged less than five years in two sentinel hospitals and group A rotavirus was detected by a double antibody sandwich ELISA. Viral RNA was extracted from positive samples and G/P gene typing was performed using a two-step nested multiplex RT-PCR. Epidemiological information (including demographic information such as age, sex and clinical symptoms) was also collected from the patients and analyzed. Results: Group A rotavirus was detected in 30.9% (785/2 541) of diarrhea samples from children. The detection rate was higher in October (54.8%, 345/629) and lower in July (5%, 5/101) each year from 2008 to 2015. The group A rotavirus infection rate was higher in boys (30.6%, 451/1 476) than in girls (31.4%, 334/1 065) (χ²=0.18, P=0.664). Infection mainly occurred in 4-12 months old patients (61.3%, 481/785) (χ²=196.69, P<0.001), and the infection rate was lower in cities (26%, 258/992) compared with rural areas (34.0%, 527/1 549) (χ²=18.19, P<0.001). G typing of 785 strains of group A rotavirus revealed the following types: G1 (13.5%, 106 strains), G2 (11.1%, 87 strains), G3 (29.7%, 233 strains), and G9 (57.5%, 451 strains); P typing revealed the predominance of P[4] (11.3%, 89 strains) and P[8] (84.7%, 665 strains); gene type combinations comprised mainly G9P[8], G2P[4], G3P[8], G1P[8], respectively accounted for 52.9% (415), 9.7% (76), 17.3% (136), 11.3% (89). Gene type combinations G1 [8] and G3P[8] have been decreasing in prevalence since 2008 and G9P[8] has become the dominant gene type of group A rotavirus in Henan province. Among the group A rotavirus infection samples, the male:female infection ratio was 1.4∶1 (451/334), with no significant difference in the infection rate (χ²=0.18, P=0.664); the infection rate was higher in 4- 12 months old patients (61.3%, 481/785), with a significant difference detected between age groups (χ²=196.69, P<0.001). The rate of detection was lower in cities (26.0%, 258/992) than in rural areas (34.0%, 527/1 549) (χ²=18.19, P<0.001). Clinical analysis revealed a body temperature of below 37 degrees in 75.7% of positive cases (594 patients), 37.0- 37.5 degrees in 17.2% of cases (135 patients), 37.6-38.0 degrees in 2.0% of cases (16 patients), and above 38 degrees in 5.1% of cases (40 patients), with most cases showing no fever or a mild fever. The frequency of episodes of diarrhea among the patients was 0- 3 times (21.1%, 166 cases), 4- 6 times (65.6%, 515 cases), 7- 9 times (8.0%, 63 cases), or 10- 15 times (5.2%, 41 cases), mainly showing mild and moderate diarrhea. Vomiting also varied in frequency among the patients from no vomiting (86.9%, 682 cases), 1-2 times (11.8%, 92 cases), 3 times (6.0%, 47 cases), and more than 3 times (0.4%, 3 cases). The occurrence of dehydration varied from no dehydration (86.9%, 682 cases), mild dehydration of 1%- 5% (12.1%, 95 cases), to severe dehydration of ≥5% (1.0%, 8 cases). Conclusion A higher infection rate of group A rotavirus was detected in children younger than five years of age with acute diarrhea in sentinel hospitals in Henan province, including part-mixed infection cases. A predominance of cases was detected in the autumn, and secondly the spring of each year. Gene type G9P[8] was most frequently isolated. The majority of patients displayed no fever, vomiting or dehydration. The cases with clinical symptoms of fever, diarrhea, vomiting and dehydration often showed mild disease.

Objective: To investigate the antimicrobial resistance and pulsed field gel electrophoresis (PFGE) patterns of S.paratyphi A strains in Zhengzhou city isolated from sentinel hospitals in 2013-2015. Methods: According to Salmonella molecular typing and K-B drug susceptibility testing method published by international PulseNet bacterial infectious disease monitoring network and USA Clinical and Laboratory Standards Institute (CLSI2015), we analyzed drug sensitivity and PFGE molecular characteristics of 67 S.paratyphi A strains(11 strains in 2013, 7 strains in 2014, 49 strains in 2015) isolated from blood and stool samples in two sentinel hospitals of fever with rash syndrome surveillance system established in Zhengzhou city in 2013-2015. Results: The results showed 67 strains of S.paratyphi A had different levels of resistance to 13 kinds of antibiotics, 65 strains were multi-drug resistant strains (97.0%), 5 isolates were resistant to 2-3 kinds of antibiotics (7.5%), 41 isolates were resistant to 5-8 kinds of antibiotics (61.2%),11 isolates were resistant to 9-10 kinds of antibiotics(16.4%),8 isolates were resistant to 11-12 kinds of antibiotics(11.9%). 67 strains of S.paratyphi A were divided into 10 molecular patterns(PTYA1-PTYA10) by digestion with XbaⅠ restriction endonuclease and pulsed field gel electrophoresis, each pattern contains 1-48 strains with similarity ranged from 94.31%-100%. PTYA3 contained 48 strains, which was predominant band type; PTYA1, 9 contained 6 strains; PTYA 2, 4, 5, 6, 7, 8, 10 contained 1 strains among them. Conclusion The status of drug resistance of clinical isolates of S.paratyphi A in Zhengzhou city was rather serious, PFGE patterns showed diversity and dominant characteristics. The PFGE patterns of partial strains and its corresponding anti-drug spectrum have certain relevance and cluster relationship.