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Group A Streptococcus (GAS) is a beta-hemolytic Streptococcus, which is often referred to as Streptococcus pyogenes in traditional clinical practice.It is the most important pathogenic bacterium in the Streptococcus genus.GAS infection and its sequelae have a huge impact on the health of children and the youth.Therefore, it has always been a serious problem that adversely affects public health and the national economy.The purpose of this article is to advocate early, rapid, and accurate diagnosis of GAS infection in order to reduce the severity of the disease, guide the rational use of antibiotics, and achieve the best cost-effectiveness effect.
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Group A Streptococcus (GAS) is a very important pathogen, especially for children.On a global scale, GAS is an important cause of morbidity and mortality.But the burden of disease caused by GAS is still unknown in China and also has not obtained enough attention.For this purpose, the expert consensus is comprehensively described in diagnosis, treatment and prevention of GAS diseases in children, covering related aspects of pneumology, infectiology, immunology, microbiology, cardiology, nephrology, critical care medicine and preventive medicine.Accordingly, the consensus document was intended to improve management strategies of GAS disease in Chinese children.
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Pneumonia is a common disease and a leading cause of death in children.Bacterial meningitis is a severe infectious disease in children, featured by high morbidity, high mortality, and high incidence of sequelae. Streptococcus pneumoniae (SP)is the main pathogenic bacteria causing community-acquired pneumonia, otitis media, sepsis, bacterial meningitis and other bacterial infectious diseases in children.The pathogen of SP should be identified before the rational use of antibiotics in clinical practice.Bacterial culture method is still the " gold standard" for the identification of SP infection pathogen, but it is not applicable to the rapid detection of SP due to the shortcomings of a low positive rate and being time consuming.Immunochromatographic tests, enzyme-linked immunosorbent tests, latex particle agglutination tests and other immunological methods have the advantages of fast detection, strong specificity, high sensitivity, and easy operation, and they are free from the influence of antibacterial agents, so they are supplement to the bacterial culture method for detection of SP infection.
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Objective To evaluate the application of partial cpsA-cpsB serotype prediction system as a serotyping method for streptococcus pneumonia.Methods Ninety-four isolates in this study were provided by Microorganism Research Room of Beijing Pediatric Research Institution,Beijing Children's Hospital Affiliated to Capital Medical University.The quelling test was applied to determine gold standard of serotypes of isolates.Polymerase chain reaction (PCR),sequencing,sequence data management and alignment were implemented previously.Results Eighty-three out of all 94 isolates were serotyped by quelling reaction,and 11 isolates were non-serotype isolates.Among the 83 isolates,67 (80.72％) isolates got positive PCR results and 60 (89.55％)isolates got results consistent with gold standard or containing gold standard.Among 12 isolates belonging to 19F,10 isolates were correctly predicted,and 2 isolates were predicted to be 6A,23F/10A.Among 19 isolates belonging to serotype 19A,1 isolate was predicted to be 35 F/47F,and the other 18 isolates were correctly predicted.Among 10 isolates belonging to serotype 14,9 isolates got results consistent with gold standard,and 1 isolate was predicted to be 19A.All 7 isolates belonging to serotype 6B were predicted to be 6A/6B and 4 isolates belonging to 23F were predicted to be 23F/10A.3 of 11 (27.27％) non-serotype isolates got positive PCR results and were predicted to be 6A/6C,6A/6B,19A.Conclusions Partial cpsA-cpsB sequencing system is a useful method for detecting streptococcus pneumoniae serotypes.
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Objective To analyze the molecular biological characteristics of Streptococcus pyogenes (GAS) causing children tonsillitis in Yangfangdian community Haidian district,Beijing between 2011 and 2013.Methods From Apr.2011 to Apr.2013,there were 94 children with tonsillitis treated in outpatient of Beijing Shijitan Hospital Affiliated to Capital Medical University,and 17 strains GAS were isolated from these pediatrician outpatients.Their encoding mature M protein gene (emm gene),7 pairs of alleles housekeeping gene (gki,gtr,murI,mutS,recP,xpt and yqiL),superantigen speA and speC genes,macrolide-resistance genes ermB,mefA and ermRT were amplified by polymerase chain reaction (PCR).The PCR amplified products of emm gene and 7 pairs of alleles housekeeping gene were sequenced.The emm gene sequences were stored in the Centers for Disease Control and Prevention database.The emm types of GAS were identified.The 7 pairs of alleles housekeeping gene sequences of GAS were sent to the multilocus sequence typing (MLST) website for their iso-allelic sequences to identify their sequence types (ST).The PCR amplified products of superantigen gene speA and speC,macrolide-resistance genes ermB,mefA and ermRT were performed with agar gel electrophoresis.The corresponding qualitative results were obtained.Results Five emm-types were discovered:emm12.0 (76.4％),emm1.0 (5.9％),emm89.0 (5.9％),emm75.0 (5.9％) and emm22.0 (5.9％) ;emm12.0 and its subtype strains had the same allelic profiles which belonged to ST36 type; emm1.0 strain belonged to ST28 ; emm89.0 strain belonged to ST101 ; emm75.0 strain belonged to ST49 ; emm22.0 strain belonged to ST46 ; 94.1％ (16/17) strains carried macrolide-resistance gene ermB.None carried macrolide-resistance genes mefA and ermRT.None carried superantigen speA gene.100.0％ (17/17 cases) carried superantigen speC gene.Conclusions emm12.0 (ST36) strain was the most common type of GAS causing the children tonsillitis in Yangfangdian community Haidian District,Beijing between 2011 and 2013.These strains mainly carry macrolide-resistance ermB and superantigen speC gene.
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Objective To investigate the distribution of the emm types and superantigens of group A streptococcal ( GAS) isolated from Chinese children. Methods Totally 222 GAS isolates collected from five Children's Hospitals of China during 2005～2006 were studied, emm types were performed by PCR and sequencing. The eight superan-tigen (SAg) genes (speA, speC, speH, speI, speG, speJ, ssa and SMEZ) were checked by PCR. Results Nine emm types were identified, of which emml2 (55. 86% ) and emml (39. 64% ) were the most prevalent types. The GAS isolates carried six or more SAg genes take 78. 39% of all the isolates in this study. The SAg gene profiles were closely associated with the emm type. Conclusion The emm type of S. pyogenes isolated from Chinese chil-dren was quite wide-spreading and SAg genes appeared to be associated with the emm type so its expression is po-tential in vaccine development.
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<p><b>OBJECTIVE</b>To investigate the nasal carriage of antibiotic-resistant pneumococci in children of < 5 years old in the following four cities, Beijing, Shanghai, Guangzhou and Xi'an.</p><p><b>METHODS</b>A total of 647 pneumococci strains were isolated and detected. Minimal inhibition concentrations (MICs) of antibiotics were determined by E-test. Disk diffusion test was used for the measurement of antimicrobial susceptibility.</p><p><b>RESULTS</b>Prevalence of penicillin non-susceptible Streptococcus pneumoniae in the four cities was 41%, with Guangzhou (60.8%) ranking first, followed by Xi'an (45%), Shanghai (37%) and Beijing (25.9%). The majority of penicillin non-susceptibility isolates (23.9% - 53.8%) had a low level of resistance (MIC 0.64 - 1.5 microg/ml). The most sensitive antimicrobials in terms of percentage of susceptible organisms were amoxicillin-clavulanic acid (99.4%), followed by ceftriaxone (92.1%); cefurxime and cefaclor were slightly more sensitive than penicillin with susceptibility of 74.8% and 77.9%. Erythromycin, tetracycline and TMP-SMZ were highly resistant (83.6%, 82.1% and 76.2% respectively). Among erythromycin resistant isolates, 100% were resistant to azithromycin, 98.6% to clarithromycin, 97.2% to roxithromycin and spiramycin, and 96.6% to clindamycin. 97.2% (141/145) were typical of the macrolides-lincosamides-streptogramons B (MLSB) resistance phenotype, and 2.8% (4/145) were M phenotype. The group of PRSP was with significantly higher rates of non-susceptibility for ceftriaxone (18.4%), cefurxime (58.6%), cefaclor (53.4%), compared with the group of PEN-S (0.5%, 1.8% and 0.2%, respectively) and the rate of multi-drug resistance in the isolates of PRSP group (92.9%) was significantly higher than that of PEN-S group (59.2%).</p><p><b>CONCLUSION</b>The rates of penicillin and multi-drug resistance among isolates of pneumococci carried nasally in are high children and the high prevalence of multi-drug resistance in the Chinese population may be becoming one of the most serious problems in this century.</p>
Subject(s)
Child, Preschool , Humans , Infant , Infant, Newborn , Anti-Bacterial Agents , Pharmacology , China , Epidemiology , Drug Resistance, Bacterial , Drug Resistance, Multiple , Prevalence , Respiratory Tract Infections , Microbiology , Streptococcus pneumoniaeABSTRACT
Objective To indicate the restriction profiles of pbps in Streptococcus pneumoniae(S.pneumoniae), and relationship between pbps profiles and the penicillin MIC.Methods The E-test MIC method was used to determinate penicillin susceptibility of 132 S.pneumoniae strains consisting of 69 penicillin susceptible S.pneumoniae (PSSP) strains and 63 nonsusceptible S.pneumoniae (PNSP) strains. Furthermore, we compared these strains by detecting restriction fragment length polymorphism (RFLP) of the PBPs genes pbp1a, pbp2b and pbp2x.Results The RFLP results showed that 9 genotypes were founded for pbp1a, in which 2 were detected from PSSP and some PNSP strains. The other 7 ones were founded mainly in the PNSP with penicillin MIC≥0.25 ?g/ml. Ten genotypes were founded for pbp2b, in which 3 were detected from PSSP and some PNSP strains. The other 7 ones, similar with pbp1a, were founded mainly in the PNSP with penicillin MIC≥0.25 ?g/ml. Thirty-one restrictive patterns were founded for pbp2x. Seventeen patternss from them were detected in PSSP, and 13 ones were founded only in PSSP. The other 14 patterns all were covered PNSP strains. A total of 47 patterns were found according to the three pbps types. Twenty-three patterns from them were detected in PSSP, and 17 ones were founded only in PSSP. The other 24 patterns all were detected in PNSP.Conclusions Results of the study are consistent with the concept that mutations in PBP1a, PBP2b and PBP2x play an important role in the development of resistance to ?-lactam antibiotics by S.pneumoniae. In the meantime, the profiles of pbps can predict penicillin susceptibility.