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Objective:To clarify the M protein ( emm gene) types and drug susceptibility characteristic variations of Group A Streptococcus (GAS) in children in Beijing. Methods:The GAS strains isolated from throat swab samples of children diagnosed with scarlet fever and pharyngeal infection in scarlet fever etiology surveillance sentinel hospitals in 16 districts of Beijing in 2018, 2019 and 2021 were analyzed retrospectively.PCR amplification and sequencing were used for emm genotyping, and the minimum inhibitory concentrations (MIC) of 10 antibiotics were determined by the broth microdilution method.The data were analyzed using χ2 test and Fisher′ s exact method between groups. Results:A total of 557 GAS strains were collected, and 11 emm genotypes ( emm1, emm3, emm4, emm6, emm11, emm12, emm22, emm75, emm89, emm128, and emm212) were detected.Of 557 strains, 238 trains were of emm1 type (42.73%), 271 strains were of emm12 type (48.65%) and 48 strains were of other emm types (8.62%). The detection rates of emm1, emm12 and other emm type genes in 2018, 2019, and 2021 were [37.50% (105/280 strains), 57.14% (160/280 strains), 5.36% (15/280 strains)], [49.05% (129/263 strains), 39.54% (104/263 strains), 11.41% (30/263 strains)], and [28.57% (4/14 strains), 50.00% (7/14 strains), 21.43% (3/14 strains)], respectively.In children infected with emm12 in 2018 and 2019, there were more children under 6 years old than children over 6 years old (62.50% vs.46.88%, 46.36% vs.30.36%) (χ 2=7.182, 6.973; all P<0.05). Drug susceptibility testing results suggested that 225 randomly selected GAS strains were all 100.00% sensitive to 7 antibiotics including Penicillin, Levofloxacin, Meropenem, Linezolid, Cefotaxime, Cefepime and Vancomycin.The rates of resistance to Erythromycin, Tetracycline and Clindamycin were [88.57% (93/105 strains), 87.62% (92/105 strains), 86.67% (91/105 strains)], and [94.34% (100/106 strains), 94.34% (100/106 strains), 87.74% (93/106 strains)] in 2018 and 2019, respectively.The test strains were 100.00% (14/14 strains) resistant to the above 3 antibiotics in 2021.MIC 50 and MIC 90 values of Penicillin in 2018, 2019, and 2021 were (0.03 mg/L, 0.03 mg/L), (0.03 mg/L, 0.06 mg/L), and (0.06 mg/L, 0.06 mg/L), respectively.Among 225 GAS strains, 207 strains had drug resistance and were resistant to more than one drug.Specifically, 94.69% (196/207 strains) were resistant to Erythromycin, Tetracycline and Clindamycin.About 4.35% (9/207 strains) were resistant to both Erythromycin and Clindamycin.A total of 0.97% (2/207 strains) were resistant to Erythromycin and Tetracycline. Conclusions:The emm genotypes of GAS in children in Beijing are diverse in 2018, 2019 and 2021.The dominant genotypes are emm12 and emm1, and emm12 is the main epidemiological type.GAS strains maintain highly resistant to Erythromycin, Clindamycin and Tetracycline, and sensitive to Penicillin and other antibiotics.However, MIC 50 and MIC 90 of Penicillin shows an ascending trend.
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Objective To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS),isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.Methods Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS.Eleven currently known SAg genes including SpeA,speC,speG,speH,speI,speJ,speK,speL,speM,smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR.Results A total of 377 GAS were isolated from 6 801 throat swab specimens,with the positive rate as 5.5％.There were obvious changes noticed among speC,speG,speH and speK in three years.A total of 45 SAg genes profiles were observed,according to the SAgs inclusion.There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emml and emml2 strains (x2=38.196,P＜0.001;x 2=72.310,P＜0.001).There also appeared significant differences in the frequencies of speA,speH,speI and speJ between emm 1 and emm 12 strains (x2 =146.154,P＜ 0.001;x2=52.31,P＜0.001;x2=58.43,P＜0.001;x2=144.70,P＜0.001).Conclusions Obvious changes were noticed among SAg genes including speC,speG,speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.SAg genes including speA,speH,speI and speJ appeared to be associated with the emm 1 and emm 12 strains.More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles,during the epidemic period.
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Objective To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS),isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.Methods Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS.Eleven currently known SAg genes including SpeA,speC,speG,speH,speI,speJ,speK,speL,speM,smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR.Results A total of 377 GAS were isolated from 6 801 throat swab specimens,with the positive rate as 5.5％.There were obvious changes noticed among speC,speG,speH and speK in three years.A total of 45 SAg genes profiles were observed,according to the SAgs inclusion.There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emml and emml2 strains (x2=38.196,P＜0.001;x 2=72.310,P＜0.001).There also appeared significant differences in the frequencies of speA,speH,speI and speJ between emm 1 and emm 12 strains (x2 =146.154,P＜ 0.001;x2=52.31,P＜0.001;x2=58.43,P＜0.001;x2=144.70,P＜0.001).Conclusions Obvious changes were noticed among SAg genes including speC,speG,speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017.SAg genes including speA,speH,speI and speJ appeared to be associated with the emm 1 and emm 12 strains.More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles,during the epidemic period.
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Objective This study aimed to explore the incidence trends and onset features of scarlet fever during the years of epidemic,from 2006 to 2015,in Beijing.Methods Spatial,temporal and population distributions,prognosis of the reported cases and surveillance data on scarlet fever and other streptococcal infections (including the patients of streptococcal infection,tonsillitis and isthmitis) were analyzed by the descriptive epidemiological methods.Results A total of 27 987 scarlet fever cases were reported from 2006 to 2015,with the incidence rates as 7.04 to 18.53 per 100 000 persons during these years,except for 2011.A total of 6 152 cases were reported in 2011,with the incidence of 31.37 per 100 000 persons,significantly higher than the average levels of the other years.There were more cases reported in rural-urban continuum,in summer and winter,with most of the cases were children in primary schools and infant-institutes.From May to December in 2011,4 332 cases were interviewed three weeks after the disease onset,and their conditions improved or recovered,with no death or complication appeared at the follow-up period.There were 2 725 cases of scarlet fever and 104 013 clinical cases of streptococcal infections reported in 36 surveillance hospitals during the same period.The ratio between numbers of scarlet fever cases and streptococcal infection was 1 ∶ 38.17.The weekly numbers of scarlet fever were remarkably correlated to the streptococcal infections,with a Pearson's correlation coefficient as 0.729 (P＜0.001).Accordingly,we estimated that about 21.4 thousand clinical cases of streptococcal infections that were caused by Group A streptococcus in 2011,in Beijing.Conclusions Incidence of scarlet fever in 2011 was significantly higher than the average levels of other years in Beijing,but characteristics on spatial,temporal and population distributions of scarlet fever remained the same,with good prognosis of the reported cases.A large number of culture-positive Group A streptococcus infections among all the clinical cases of streptococcal infection might have been served as important source on septic infection,of scarlet fever.
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Objective This study aimed to explore the incidence trends and onset features of scarlet fever during the years of epidemic,from 2006 to 2015,in Beijing.Methods Spatial,temporal and population distributions,prognosis of the reported cases and surveillance data on scarlet fever and other streptococcal infections (including the patients of streptococcal infection,tonsillitis and isthmitis) were analyzed by the descriptive epidemiological methods.Results A total of 27 987 scarlet fever cases were reported from 2006 to 2015,with the incidence rates as 7.04 to 18.53 per 100 000 persons during these years,except for 2011.A total of 6 152 cases were reported in 2011,with the incidence of 31.37 per 100 000 persons,significantly higher than the average levels of the other years.There were more cases reported in rural-urban continuum,in summer and winter,with most of the cases were children in primary schools and infant-institutes.From May to December in 2011,4 332 cases were interviewed three weeks after the disease onset,and their conditions improved or recovered,with no death or complication appeared at the follow-up period.There were 2 725 cases of scarlet fever and 104 013 clinical cases of streptococcal infections reported in 36 surveillance hospitals during the same period.The ratio between numbers of scarlet fever cases and streptococcal infection was 1 ∶ 38.17.The weekly numbers of scarlet fever were remarkably correlated to the streptococcal infections,with a Pearson's correlation coefficient as 0.729 (P＜0.001).Accordingly,we estimated that about 21.4 thousand clinical cases of streptococcal infections that were caused by Group A streptococcus in 2011,in Beijing.Conclusions Incidence of scarlet fever in 2011 was significantly higher than the average levels of other years in Beijing,but characteristics on spatial,temporal and population distributions of scarlet fever remained the same,with good prognosis of the reported cases.A large number of culture-positive Group A streptococcus infections among all the clinical cases of streptococcal infection might have been served as important source on septic infection,of scarlet fever.
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Objective To explore the relationship between superantigen and M protein gene (emm)-types genes of Group A Streptococcus pyogenes (GAS) isolated from patients with scarlet fever in Beijing from May 2012 to July 2013 .Methods GAS was isolated from specimens of patients with scarlet fever . Superantigen genes (speA ,speB ,speC ,speF ,speG ,speH ,speI ,speJ ,speL ,speK ,speM ,ssa ,and smeZ) ,and emm gene were amplified by polymerase chain reaction .Rate and proportion were compared by chi-square test .Results Of the 423 GAS strains isolated from patients with scarlet fever from 2012 to 2013 ,most of the isolates possessed speB (97 .6% ) ,speC (99 .8% ) ,speF (98 .3% ) ,speG (99 .8% ) , smeZ (94 .1% ) and ssa (88 .4% ) ,and some of them possessed speH (54 .6% ) ,speI (53 .4% ) ,speA (45 .2% ) and speJ (43 .5% ) ,but very few isolates possessed speK (2 .4% ) ,speL (1 .4% ) and speM (1 .7% ) .Type emm12 (59 .5% ) and type emm1 (37 .4% ) were the main types of GAS .Most of the emm12-type isolates possessed speH (84 .8% ) and speI (84 .0% ) compared with only 4 .0% of speH and 3 .4% of speI in type emm1 .Most of type emm1 possessed speA (95 .3% ) and speJ gene (94 .6% ) compared with only 17 .3% of speA and 14 .8% of speJ in type emm12 .The superantigen genes profiles were significant different between emm 1-type and emm 12-type isolates (P< 0 .05) .Conclusion Type emm1 and type emm12 are epidemic strains in patients with scarlet fever from 2012 to 2013 in Beijing ,and emm gene-types are associated with superantigen genes profiles .
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A multi-stage stratified sampling method and a self-designed questionnaire were used to evaluate the prevalence of conjunctivitis symptoms and associated factors among the Beijing residents.In total,12 890 residents aged over 18 years were recruited from 6 districts.The reported prevalence of conjunctivitis symptom at the last years was 1.60％.Self-reported health condition and personal health behaviors were risk factors associated with conjunctivitis among adult Beijing residents.No significant difference existed between different districts,age groups,educational levels,gender and races.Conjunctivitis symptom among Beijing residents was related with health condition and health behaviors.More measures should be taken to cultivate the health model of behaviors.
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To assess the level of health skills relating to infectious diseases among residents in Beijing and develop more effective strategies for controlling infectious diseases.We conducted a multistage sampling,retrospective cross-sectional survey of residents aged 18 and above from 6 districts by selfadministered and anonymous questionnaires in January 2011.The questionnaires consisted of health skills relating to infectious diseases.A total of 13 042 respondents completed the survey.The proportions of people with the skills for acquiring knowledge about infectious diseases,being able to read medicinal package insert,being able to read brochures with regard to basic knowledge about infectious diseases, being able to read laboratory test report andproper use of thermometer were 57.7％,71.0％,70.2％,47.9％ and 76.8％ respectively.The levels of health skills were different among different populations (P ＜0.01).A low level of health skills was observed among the poorly-educated people and elders.Therefore measures such as health education and skills training about infectious diseases should be taken to improve the health skills.