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Ma X.,National Key Discipline of Pediatrics Capital Medical University | Yao K.-H.,National Key Discipline of Pediatrics Capital Medical University | Xie G.-L.,Lanzhou Institute of Biological Products | Zheng Y.-J.,Shenzhen Childrens Hospital | And 12 more authors.
Chinese Medical Journal | Year: 2013

Background Erythromycin-resistant Streptococcus pneumoniae isolates that causing invasive pneumococcal diseases (IPD) in Chinese children remain uncharacterized. This study aims to identify the resistance genes associated with erythromycin resistance and to determine the genetic relationships of IPD isolates in Chinese children. Methods A total of 171 S. pneumoniae strains were isolated from 11 medical centers in China from 2006 to 2008. All the isolates were characterized via serotyping and antibiotic susceptibility determination. The erythromycin-resistant isolates were further characterized via ermB and mefA gene detection, multi-locus sequence typing analysis, and pulsed-field gel electrophoresis. Results A total of 164 (95.9%) isolates showed resistance to erythromycin, of which 162 strains with high high-level resistance (MIC ≥ 256 μg/ml). A total of 104 (63.4%) isolates carry the ermB gene alone, whereas 59 (36.0%) harbor both ermB and mefA genes. Of the 59 strains, 54 were of serotypes 19A and 19F and were identified as highly clonal and related to the Taiwan19F-14 clone. Conclusions The erythromycin resistance rate in IPD isolates is significantly high and is predominantly mediated by the ermB gene. Isolates that carry both ermB and mefA genes are predominantly of serotypes 19A and 19F. Source


Wang P.,National Key Discipline of Pediatrics Capital Medical University | Wang P.,Capital Medical University | Tong J.,National Key Discipline of Pediatrics Capital Medical University | Shi W.,National Key Discipline of Pediatrics Capital Medical University | And 3 more authors.
International Journal of Infectious Diseases | Year: 2015

Background: Group B Streptococcus (GBS) is an important neonatal pathogen associated with high morbidity and mortality in developed countries. However, data describing neonatal GBS disease in developing countries, particularly in Asia, are largely incomplete. The aim of this study was to determine the serotype distribution, antimicrobial resistance, and molecular characteristics of invasive GBS isolates recovered from Chinese neonates. Methods: From 2008 to 2013, 40 GBS isolates were recovered from infected neonates less than 3 months of age. All isolates were identified with the CAMP test and commercially available techniques. Serotyping was performed by latex agglutination. Antibiotic susceptibility was tested with Etest strips and the disk diffusion method. Multilocus sequence typing and erythromycin resistance gene detection (ermB and mefA) were performed by PCR. Results: Four serotypes were identified. Serotype III (85%) was the most prevalent, followed by Ia (7.5%), Ib (5%), and V (2.5%). All isolates were sensitive to penicillin, ceftriaxone, and levofloxacin. However, resistance to erythromycin (92.5%), clindamycin (87.5%), and tetracycline (100%) was observed. Among erythromycin-resistant isolates, 73.0% carried the ermB gene alone, 5.4% carried the mefA gene alone, and 21.6% expressed both ermB and mefA genes. A total of seven sequence types (STs) were identified; the most prevalent was ST17, accounting for 80% of all isolates. Further, serotype III isolates contained ST17 (94.2%), ST19 (2.9%), and ST650 (2.9%). Conclusion: Serotype distribution, antimicrobial susceptibility, and sequence type characterization in Asia and in other global regions may contribute to improve the prevention and treatment of neonatal GBS infections. © 2015 The Authors. Source


Sun L.,National Key Discipline of Pediatrics Capital Medical University | Tian J.-L.,National Key Discipline of Pediatrics Capital Medical University | Yin Q.-Q.,National Key Discipline of Pediatrics Capital Medical University | Xiao J.,National Key Discipline of Pediatrics Capital Medical University | And 9 more authors.
PLoS ONE | Year: 2015

Interferon Gamma Release Assays (IGRAs) were developed for the indirect or immunologic diagnosis of tuberculosis infection; however, they have also been used to assist in difficult to diagnose cases of tuberculosis disease in adults, and to a lesser extent, in children, especially in those under 5 years old. We evaluated the utility of using an IGRA in pediatric tuberculosis in younger children in a hospital setting. The diagnostic accuracy of T-SPOT.TB and TST was assessed in 117 children with active tuberculosis and 413 children with respiratory tract infection. Sensitivity and specificity were calculated for the tests used individually and together. Concordance was also calculated. Sensitivity of T-SPOT.TB (82.9%) was higher than TST (78.6% using a 5mm cut-off), especially in children confirmed to have TB. TSPOT. TB was more specific than TST using a 5mm cut-off (96.1% vs. 70.9%). Combining T-SPOT.TB and TST results improved the sensitivity to 96.6%. In conclusion, the results of the current study indicate that T-SPOT.TB has good sensitivity and specificity, supporting its use among patients of this age. A combination of IGRA and TST would be useful additions to assist in the diagnosis of childhood TB. © 2015 Sun et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in anymedium, provided the original author and source are credited. Source


Shi W.,National Key Discipline of Pediatrics Capital Medical University | Yao K.,National Key Discipline of Pediatrics Capital Medical University | He M.,National Key Discipline of Pediatrics Capital Medical University | Yu S.,National Key Discipline of Pediatrics Capital Medical University | Yang Y.,National Key Discipline of Pediatrics Capital Medical University
BMC Infectious Diseases | Year: 2014

Background: In this study, we defined the population biology of serogroup 6 Streptococcus pneumoniae collected in China and their antibiotic resistance profiles. Methods: The serotypes of 225 S. pneumoniae strains isolated between 1997 and 2011 were identified with the Quellung reaction and serotype-specific PCR. All isolated pneumococci were tested for their sensitivity to 11 kinds of antibiotics with the E-test method or disc diffusion. The sequence types (STs) were analyzed with multilocus sequence typing (MLST). Results: The frequencies of serotypes and subtypes 6A, 6B-I, 6B-II, 6C, and 6D among the 225 isolates were 46.7% (105/225), 19.6% (44/225), 25.8% (58/225), 6.2% (14/225), and 1.8% (4/225), respectively. Serotype 6E was not found in the serotype 6A isolates, and neither serotype 6F nor 6G was identified in any isolate. MLST analysis revealed 58 STs. The most common STs were ST982 (23.1%), ST90 (14.7%), ST4542 (7.6%), and ST2912 (4.9%). The rates of clonal complex 90 (CC90) and CC386 among the oral-penicillin-nonsusceptible isolates decreased over the years, whereas the rates of CC855 and CC3173 increased. The four CCs had similar penicillin MIC distributions, with a maximum MIC of 2 μg/ml. Conclusions: This study identified the serotypes/subtypes and CCs/STs of group 6 S. pneumoniae present in China. No salient antibiotic-resistant clones were isolated among the serogroup 6 S. pneumoniae. © 2014 Shi et al.; licensee BioMed Central Ltd. Source


Yin J.,National Key Discipline of Pediatrics Capital Medical University | Yu S.,National Key Discipline of Pediatrics Capital Medical University | Liu X.,National Key Discipline of Pediatrics Capital Medical University | Li Y.,National Key Discipline of Pediatrics Capital Medical University | And 5 more authors.
Diagnostic Microbiology and Infectious Disease | Year: 2012

Beta-Hemolytic group G streptococci cause a considerable invasive disease burden and sometimes disease outbreaks. Little is known about the critical epidemiologic parameter of genetic relatedness between isolates. We determined the emm types of 65 Streptococcus dysgalactiae subsp. equisimilis isolates. We formulated multilocus sequence typing (MLST) primers with 6 of the 7 loci corresponding to the Streptococcus pyogenes MLST scheme. We performed MLST with 69 S. dysgalactiae subsp. equisimilis isolates to represent each emm type identified. These strains were further analyzed by pulsed-field gel electrophoresis (PFGE) typing. Sixteen emm types were observed. Eighteen unique combinations of allelic profiles (sequence types [STs]) were obtained with 12 profiles each accounting for multiple isolates. Forty-one MLST STs were observed. Analysis of the PFGE patterns generated revealed 10 clones. Over 80% of the isolates were distributed in 3 large clones. Isolates within 16 redundantly represented S. dysgalactiae subsp. equisimilis emm types shared identical or nearly identical STs and subtypes of PFGE, demonstrating concordance between the emm type and genetic relatedness. It is conceivable that some particular characteristics in the genomes of these strains are responsible for their predominance in different regions. © 2012 Elsevier Inc. Source

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