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.

Objective To obtain better insights into transmission dynamics of macrolide resistance genes between human and animal Enterococcus strains.Methods The antimicrobial susceptibility to 8 anti-bioties of 52 Enterococci isolated from animal and 55 Enterococci isolated from human was determined.PCR was used to detect the macrolide resistance genes ermB and mefA,tetracycline resistance genes tetM,and the integrase gene int of Tnl545 of the total 107 strains.Forty-nine ermB positive strains were chosen to be se-quenced.Filter mating experiments were taken.Results The resistance rate to erythromycin were 89.09% and 80.77%for isolates from human and animal:and resistance rate to tetracycline were 80.00%and 67.3l%for isolates from human and animal.respectively.All isolated Enterococci strains were found sensi-tive to vancomycin ermB was detected in 61.82% human Enterococci and 53.85% porcine ones.Identical er-mB gene sequences were found in animal and human Enterococci.Transfer of the ermB gene from porcine E.faecalis to human E.feacalis was successful.and the transfer frequency is 1.2×10-5.Conclusion En-terococci have a high resistance rate to erythromycin and some other antibio tics,especially in pediatric iso-lates:but still very sensitive to glycopeptide.ermB was the predominant genes for macrolide and tetracy-cline.Identical ermB gene sequences were present in animal and human Enterococci and that transfer of the ermB gene from porcine E.faecalis to human E.faecalis and vice versa is possible.but probably occurs at a low frequency.

Objective To determine the drug-resistance rate of Enterococci isolated from patients of 5 padiatric hospitals located at different areas in China,and to investigate the distribution of resistance genes ermB,mefA,tetM and the integrase gene intTn of Tn1545 in Enterococci.Methods The antimicrobial susceptibility to 8 antibiotics of 2 216 Enteroeocei isolates was determined.PCR was used to detect the macrolide resistance genes ermB and mefA,tetracycline resistance genes tetM,and the integrase gene int-Tn of Tn1545.Results The resistance rates to erythromycin,ampicillin,gentamicin and teicoplanin were 86.5%,48.0%,60.5% and 0.7%,respectively.All isolated Enterococci straim were found sensitive to vancomycin.Of the detected 225 strains,70.7% of the 225 detected strains carried ermB gene while 75.1% of them carried tetracycline resistance gene tetM:only one strain had mefA.The presence of ermB gene in erythromycin MIC＞256 mg/L straim group(95.7%)strains was higher than those in erythromycin MIC＜256 mg/L group(2.5%).The int-Tn gene was detected in 40.9%(92/225)of the 225 test strains.The presence of ermB gene in int-Tn positive group strains was higher(84.8%)than those in int-Tn negative strains group(60.9%).So did the tetM in int-Tn positive group(83.7%)compared with those in int-Tn negative group(70.0%).Conclusions Enterococci sbowed a high resistance rate to the antibiotics we monitored,especially to erythromycin;but still very senstive to glycopeptide antibiotics. Resistance to macrolide in Enterococci collected from clinical in five Children's Hospital was generally mediated by methylation of 23S rRNA via ermB methylase. Enterococci resistance to tetracycline was predominantly due to ribosomal protection encoded by tetM. There was a strong relationship of the ermB and tetM genes with Tn1545-related elements.

Streptococcal toxic shock syndrome (STSS) is a Group A Streptococcus (GAS) induced invasive infectious disease, which is characterized by abrupt onset and rapid progression with a high mortality rate.With the wide application of antimicrobial agents, the incidence of GAS infections has been substantially reduced.Nevertheless, STSS usually causes shock and multiple organ failure at the early stage of its clinical process, and the clinical symptoms are non-specific.Therefore, early identification, timely anti-infection and symptomatic treatment are particularly critical.Clinicians should pay high attention to the disease.

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.

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has spread around the world. However, approaches to distinguish COVID-19 from pneumonia caused by other pathogens have not yet been reported. We retrospectively analyzed the clinical data of 97 children with probable COVID-19. A total of 13 (13.4%) patients were confirmed positive for SARS-CoV-2 infection by nucleic acid RT-PCR testing, and 41 (42.3%) patients were found to be infected with other pathogens. Notably, no pathogen was detected in 43 (44.3%) patients. Among all patients, 25 (25.8%) had familial cluster exposure history, and 52 (53.6%) had one or more coexisting conditions. Fifteen (15.5%) patients were admitted or transferred to the PICU. In the 11 confirmed COVID-19 cases, 5 (45.5%) and 7 (63.6%) were positive for IgM and IgG against SARS-CoV-2, respectively. In 22 patients with suspected COVID-19, 1 (4.5%) was positive for IgG but negative for IgM. The most frequently detected pathogen was Mycoplasma pneumonia (29, 29.9%). One patient with confirmed COVID-19 died. Our results strongly indicated that the detection of asymptomatic COVID-19 or coexisting conditions must be strengthened in pediatric patients. These cases may be difficult to diagnose as COVID-19 unless etiologic analysis is conducted. A serologic test can be a useful adjunctive diagnostic tool in cases where SARS-CoV-2 infection is highly suspected but the nucleic acid test is negative.
Age Factors ; COVID-19/diagnosis* ; COVID-19 Testing ; Child ; Child, Preschool ; China ; Female ; Hospitalization ; Humans ; Infant ; Male ; Retrospective Studies ; SARS-CoV-2/isolation & purification* ; Symptom Assessment