Nasopharyngeal carriage rate, antimicrobial resistance and serotype distribution of Streptococcus pneumoniae among children with upper respiratory infection / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate nasopharyngeal carriage rate, antimicrobial resistance and serotype distribution of Streptococcus pneumoniae among children with upper respiratory infection.</p><p><b>METHODS</b>Nasopharygeal swabs were collected from children with upper respiratory infection visiting the outpatient department of Beijing Children′s Hospital between March 2013 and February 2014. The antibiotic susceptibility was tested by Etest method, and the serotype was determined by Quellung reaction.</p><p><b>RESULTS</b>The nasopharyngeal carriage rate for Streptococcus pneumoniae was 23.8% (699/2 941). One hundred isolates were randomly chosen for antimicrobial susceptiblity test and serotyping. Up to 98.0% isolates were susceptible to parenteral penicillin. The susceptible rate against oral penicillin, however, was 33.0%. The non-susceptible rate to erythromycin and azithromycin was 97.0%. The multi-drug resistance rate was up to 86.0%. The common serotypes were 6A(12.0%), 19F(12.0%), 6B(10.0%), 23F(9.0%) and 14(8.0%). The coverage rates of 7-, 10- and 13-valent pneumococcal conjugate vaccine were 41.0%, 42.0% and 59.0% respectively.</p><p><b>CONCLUSIONS</b>About 25% of children with upper respiratory infection are nasopharyngeal colonized by Streptococcus pneumoniae. The isolates show a high antimicrobial resistance. The 13-valent pneumococcal conjugate vaccine covers about 60.0% of the isolates.</p>

Association of NFATc1 gene polymorphism with ventricular septal defect in the Chinese Han population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Congenital heart disease (CHD) is a diverse group of diseases determined by genetic and environmental factors. Considerable research has been done on genes associated with the development of the heart. Recently, focus is on the role of transcription factor NFATc1 in the development of proper valve and septa. As part of a larger study, high density single nucleotide polymorphism (SNP) scanning was used to explore the relationship between NFATc1 gene polymorphism and susceptibility to ventricular septal defect (VSD) in the Chinese Han population.</p><p><b>METHODS</b>One hundred and ninety-two pediatric patients with congenital VSD and 192 matching healthy control subjects were studied. The haplotype reconstructions were calculated by PHASE2.0 software. Haploview software was used to perform linkage disequilibrium assessment and define haplotype blocks. The algorithm used for defining the blocks was the confidence interval method.</p><p><b>RESULTS</b>The NFATc1 gene region can be divided into 11 haplotype blocks. Strong linkage disequilibrium existed within blocks 6, 8, 9, and 11. Three SNPs (rs7240256, rs11665469, and rs754505) within the NFATc1 gene had significant correlation with VSD by single marker association analysis. In addition, two haplotypes correlated with VSD.</p><p><b>CONCLUSIONS</b>NFATc1 is associated with the occurrence of VSD and it may be a predisposing gene to CHD in Han Chinese. This finding has set a direction for further genetic and functional studies.</p>

Genotype and phenotype polymorphisms of NAT2 and CYP2E1 in the Han Chinese pediatric population / 中国当代儿科杂志

<p><b>OBJECTIVE</b>N-acetyltransferase 2 (NAT2) and cytochrome P450 2EI (CYP2E1) play a crucial role in the drug metabolic process. The aim of this study was to understand the genotype and phenotype polymorphisms of NAT2 and CYP2E1 in the Han Chinese pediatric population in order to provide a theoretical basis for individualized drug treatment.</p><p><b>METHODS</b>A total of 341 (211 males and 130 females) randomly sampled Han Chinese children, aged from 2 months to 14 years, were enrolled in this study. Genotyping was carried out by PCR method, and metabolic phenotypes were identified.</p><p><b>RESULTS</b>In this study population, wild genotype was found as a major genotype in seven SNPs of NAT2, rs1801279, rs1041983, rs1801280, rs1799929, rs1799930, rs1208 and rs1799931. The frequency of NAT2 fast metabolism was highest (61.3%), followed by middle to slow metabolism (34.1%). Wild genotype also predominated in the four SNPs of CYP2E1 (rs2031920, rs3813867, rs6413432 and rs72559720) named as CYP2E1*5, *6 and *2, with a frequency of 61.3%, 60.1% and 99.4% respectively. As the relationship between CYP2E1 genotype and phenotype was unknown, phenotyping of CYP2E1 was not done.</p><p><b>CONCLUSIONS</b>The important SNPs of NAT2 and CYP2E1 are predominantly wild genotype in the Han Chinese pediatric population. Fast metabolic phenotype predominates in important SNPs of NAT2.</p>

Association of immunophenotypic characterization of peripheral lymphocytes with different clinical phenotypes of tuberculosis in Chinese Han children / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Very few researchers have studied the changes in peripheral lymphocyte patterns in adult tuberculosis (TB) and even less researches have been conducted in pediatric TB. In this study, we obtained blood samples from 114 Chinese pediatric TB patients and 116 matched controls to study the association of phenotypic subsets of peripheral lymphocytes with different clinical phenotypes of TB.</p><p><b>METHODS</b>The subjects were classified as the control group and the TB patients group which were further divided into a pulmonary TB group and an extra-pulmonary TB group (more serious than the former). The distribution of lymphocyte subpopulations, including T lymphocytes, CD4(+) T lymphocytes, CD8(+) T lymphocytes, B lymphocytes, and natural killer (NK) cells, were quantitatively analyzed by flow cytometry.</p><p><b>RESULTS</b>Compared to the healthy controls, TB infection was associated with significantly higher B cell (P < 0.0001), and lower T cell (P = 0.029) and NK cell (P < 0.0001) percentages. Compared to pulmonary TB patients, extra-pulmonary TB was associated with relatively higher B cell (P = 0.073), and lower T cell percentages (P = 0.021), higher purified protein derivative (PPD) negative rate (P = 0.061), and poorer PPD response (P = 0.010). Most pulmonary TB cases were primary pulmonary TB (89.1%), and most extra-pulmonary TB cases had TB meningitis (72.1%).</p><p><b>CONCLUSIONS</b>This study demonstrates changes in the lymhocyte distribution in children suffering from different clinical phenotypes of TB; such as primary pulmonary TB, and TB meningitis. These patterns may have significance in understanding the pathogenesis and prognostic markers of the disease, and for developing immunomodulatory modalities of therapy.</p>

Transcription factor HAND2 mutations in sporadic Chinese patients with congenital heart disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The basic helix-loop-helix transcription factor HAND2 plays an essential role in cardiac morphogenesis. However, the prevalence of HAND2 mutations in congenial heart disease (CHD) and the correlation between the HAND2 genotype and CHD phenotype have not been studied extensively.</p><p><b>METHODS</b>We amplified the exons and the flanking intron sequences of the HAND2 gene in 131 patients diagnosed with congenital defects of the right ventricle, outflow tract, aortic artery or cardiac cushion and confirmed the mutations by sequencing.</p><p><b>RESULTS</b>Seven mutations including three missense mutations (P11R, S36N and V83L), one isonymous mutation (H14H) and three mutations in untranslated region (241A > G, 604C > T and 3237T > A) were identified in 12 out of the 131 patients. Both nonisonymous mutations are located in the transcriptional activation domain on the N-terminus. Only one mutation (S36N) was identified in 250 normal healthy controls. The distribution of 3637T > A is the unique one which was different between the 2 groups.</p><p><b>CONCLUSIONS</b>HAND2 may be a potential candidate gene of stenosis of the right ventricle, outflow tract. Further study of those with a family history of HAND2 mutations will help convincingly relate their genotype to the pathogenesis of CHD.</p>

IFN-γ release assay: a diagnostic assistance tool of tuberculin skin test in pediatric tuberculosis in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Prompt diagnosis of Mycobacterium tuberculosis (MTB) infection is an essential step in tuberculosis control and elimination. However, it is often difficult to accurately diagnose pediatric tuberculosis (TB). The tuberculin test (TST) may have a low specificity because of cross-reactivity with antigens present in Mycobacterium bovis bacillus Calmette-Guerin (BCG) and other mycobacteria, especially in China with a predominantly BCG-vaccinated population. Early-secreted antigenic target 6-kDa protein (ESAT-6) and culture filtrate protein 10 (CFP-10), stand out as suitable antigens that induce an interferon-gamma (IFN-γ) secreting, T-cell-mediated immune response to infection. While, considered the higher costs and complexity of the IFN-γ release assay (TSPOT), we aimed to evaluate the TSPOT and TST test in the clinical diagnosis of pediatric tuberculosis and to establish a diagnostic process suitable for China.</p><p><b>METHODS</b>The sensitivity and specificity of the assay were evaluated in total seventy four children with active tuberculosis and fifty one nontuberculous children with other disease, and then the results were compared with TST. Logistic regression models were used to identify variables that were associated with positive results for each assay. The independent variables included sex, age, birth place, vaccination history, close contract with an active TB patient.</p><p><b>RESULTS</b>The sensitivity of TSPOT was higher than TST in active TB children with or without BCG vaccination, as well as in children with culture-confirmed TB. But the difference was not significant statistically. Combining results of the TSPOT and TST improved the sensitivity to 94.6%. Agreement of the TST and TSPOT was low (77.0%, κ = 0.203) in active TB patients. The difference in specificity between TSPOT and TST test was statistically significant (94.1% vs. 70.6%, P = 0.006). Specificity of the two tests in patients without prior BCG vaccination history was similar (80.0% vs. 60.0%). The concordance between the two tests results in BCG vaccinated subjects was low (71.7%, κ = 0.063). For TSPOT, none of the included risk factors was significantly associated with positive results. For TST, BCG vaccination (OR: 1.78; 95%CI: 1.30 - 2.00) was significantly associated with positive results.</p><p><b>CONCLUSIONS</b>Although IFN-γ release assay had relatively high sensitivity and specificity, we also should consider the higher costs and complexity of this test. Therefore, TSPOT could be used as the complementary tool of TST in circumstances when a suspected patient with negative TST results, or to exclude a positive TST result caused by BCG vaccination.</p>

Comparison on discriminatory power of different variable number tandem repeats locus-set on genotyping of mycobacterium tuberculosis isolated in China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To evaluate the application of different variable number tandem repeats (VNTR) locus in genotyping of Mycobacterium tuberculosis (M.tuberculosis) strains isolated from eight provinces in China, and to find the suitable locus-set of VNTR for epidemical strains in China.</p><p><b>METHODS</b>All 140 M.tuberculosis strains were randomly selected from 2800 M.tuberculosis strains isolated from eight provinces in China, 27 VNTR loci were used for typing all isolates. Discriminatory power (Hunter-Gaston Index, HGI) of every locus and different locus-set were analyzed by BioNumerics software. Meanwhile, Spoligotyping was used to identify Beijing family and non-Beijing family. Then the HGI of different locus-sets in two families was also evaluated.</p><p><b>RESULTS</b>All 140 isolates were clustered into Beijing kindred (112 strains, 80%) and non-Beijing kindred (28 strains, 20%) by Spoligotyping. The discriminatory power of Spoligotyping in 140 isolates was 0.4589. Every locus showed different polymorphism and HGI were from 0 to 0.809. The number of VNTR loci with HGI higher than 0.5 in all strains, Beijing family and non-Beijing family was 8, 7 and 14 respectively. 27 loci were combined into four groups which included 8, 12, 15 and 24 VNTR loci respectively. Four locus-sets showed different polymorphism, HGI of eight-locus, 12-locus, 15-locus, and 24-locus set in 140 strains was 0.9991, 0.9882, 0.9980 and 0.9986, and their discriminatory power were calculated in Beijing kindred (HGI: 0.9987, 0.9318, 0.9969 and 0.9975) and non-Beijing kindred (HGI: 1, 0.9894, 1 and 1).</p><p><b>CONCLUSION</b>Different VNTR locus and locus-set showed different discriminatory power in the selected M.tuberculosis strains isolated from China. Eight-locus set can be used in molecular epidemiological study of M.tuberculosis in China after standardization.</p>

Association of NRAMP1 gene polymorphisms with the susceptibility to tuberculosis in ethnic Han Chinese children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Tuberculosis is still a public health problem. Host genetic factors, such as polymorphisms in NRAMP1 gene, may play a role in the development of tuberculosis. To clarify the effect of NRAMP1 gene polymorphisms on the development of childhood tuberculosis, the association of NRAMP1 gene polymorphisms with susceptibility to tuberculosis in the ethnic Han Chinese children was investigated.</p><p><b>METHODS</b>From January 2005 to March 2008, 130 ethnic Han children with tuberculosis (TB group) were enrolled. Three hundred and ninety hospitalized ethnic Han children for physical examination in the surgery department were used as the control group. The controls were matched with tuberculosis children by age, sex and area. PCR-RFLP analysis was performed on DNA samples to identify allele genotypes of INT4 and D543N in NRAMP1 gene. Genotype frequency differences between tuberculosis patients and controls were analyzed using x2 test.</p><p><b>RESULTS</b>No statistical difference was found in the genotype frequency of variants G/C and C/C at the INT4 locus between the TB and the control groups. At the D543N locus, the frequency of genotype variants (G/A and A/A) was significantly higher in the TB group (34/130) than that in the control group (66/390) (x2=5.349, P<0.05; OR=1.74, 95%CI=1.08-2.79). When stratified by sex, differences in the genotype distribution were observed only in females at the D543N locus, which the variant genotypes were higher in the TB group (16/52) than in the control group (21/155) (x2=7.866, P<0.05; OR=2.84, 95%CI=1.34-5.99). For males, there was no difference between the TB and the control groups. At the INT4 locus, no difference was observed between the two groups in boys and girls.</p><p><b>CONCLUSIONS</b>Genotypic variation at the D543N locus in NRAMP1 gene may be associated with susceptibility to tuberculosis in ethnic Han Chinese children. Variant genotypes in NRAMP1 gene (G/A and A/A) may be susceptible genotypes to tuberculosis in ethnic Han Chinese children. Girls with variant genotypes were more susceptible to tuberculosis.</p>

Association of TBX5 gene polymorphism with ventricular septal defect in the Chinese Han population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Congenital heart disease is a diverse group of diseases determined by genetic and environmental factors. Considerable research has been done on genes associated with development of the heart. A recent focus is the role of transcription factor TBX5 in the development of atria, left ventricle and conduction system. As part of a larger study, high density, single nucleotide polymorphism (SNP) scanning was used to explore the relationship between TBX5 gene polymorphism and susceptibility to ventricular septal defect not associated with forelimb malformation in the Chinese Han population.</p><p><b>METHODS</b>One hundred and ninety two paediatric patients with congenital ventricular septal defect and 192 matched healthy control subjects were studied. The haplotype reconstructions were calculated by PHASE2.0 software. Haploview software was used to perform linkage disequilibrium assessment and defining of haplotype blocks. The algorithm used for defining of blocks was the confidence interval method.</p><p><b>RESULTS</b>The TBX5 gene region can be divided into 3 haplotype blocks of 27, 15 and 2 SNPs. Strong linkage disequilibrium exists within each block. SNP rs11067075 within the TBX5 gene had significant correlation with ventricular septal defect (P = 0.0037) by single marker association analysis. In addition, a 20 kb haplotype composed of 27 SNPs correlated with ventricular septal defect (P = 0.05, multiple loci regression analyses based on reconstructed haplotype blocks).</p><p><b>CONCLUSIONS</b>TBX5 is associated with the occurrence of ventricular septal defect and may be a predisposing gene to congenital heart disease in Han Chinese. This finding has set a direction for further genetic and functional studies.</p>

Molecular characteristics of rifampin and isoniazid resistant Mycobacterium tuberculosis strains from Beijing, China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>China is one of the high burden countries of Mycobacterium tuberculosis (TB) infection globally, with high incidence and mortality. We studied the molecular characteristics of rifampin (RIF) and isoniazid (INH) resistant Mycobacterium tuberculosis strains from Beijing, China, in order to find out the genetic marker for rapid detection of specific drug resistance.</p><p><b>METHODS</b>Forty pansusceptible and 81 resistant strains of Mycobacterium tuberculosis isolated from Beijing, China during 2002-2005 were analyzed. The modified rifampin oligonucleotide (RIFO) assay based on reverse line blot hybridization was used to detect mutations in the 81 bp hot-spot region of rpoB gene, which is associated with RIF resistance. The INH resistance associated genes, regulatory region mab-inhA (-15C/T) and structural gene katG S315T were detected by reverse line blot hybridization and PCR-restriction fragment length polymorphism (RFLP) method respectively. All the strains were typed by spoligotying and the Beijing genotype was further subdivided by NTF locus analysis. The distribution of drug resistance associated mutations in the above genes was compared in these groups.</p><p><b>RESULTS</b>Sixty-five (91.5%) of 71 RIF resistant and 52 (92.9%) of 56 multidrug-resistant (MDR, i.e. resistant to at least RIF and INH) strains were found to harbor mutations in the rpoB hot-spot region. No mutation was detected in RIF sensitive strains. The specificity and sensitivity of the modified RIFO assay were 100% and 91.5%, respectively. katG315 AGC>ACC and inhA-15C>T mutations were found in 40 (60.6%) and 10 (15.2%) of 66 INH resistant strains, respectively; 7.6% of INH-resistant strains had mutations in both of these genes. Therefore, a combined use of both katG315 and inhA-15 identified 68.2% of INH-resistant strains. The Beijing genotype accounted for 91.7% of total strains and was further subdivided into "modern" (76.6%) and "ancestral" (23.4%) group. There is no significant difference between "ancestral" and "modern" group in prevalance of drug resistance-associated gene mutations.</p><p><b>CONCLUSIONS</b>The hot-spot region of rpoB gene can be used as genetic marker for detection of RIF resistant strains; a combined use of both katG315 and inhA-15 can improve the detection rate of INH resistant strains; the Beijing genotype is prevalent in Beijing, China; the modified RIFO assay can be a practical tool for rapid detection of RIF resistant and MDR isolates in the routine diagnostic work.</p>

With genechip technique to investigate HLA-DQB1 gene polymorphisms in south and north regions of China / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To research and compare HLA-DQB1 gene frequency(GF) and polymorphism distribution between south and north population of Chinese in China.</p><p><b>METHODS</b>Combining PCR-sequence specific primers(SSP) and sequence specific oligonucleotide probe(SSOP) techniques and DNA Microarray Kit for HLA-DQB1 Low Res Genotyping from Shenzhen Yi-Shengtang Biological LTD. Co. was used to type HLA-DQB1 gene polymorphisms of 700 individuals living in south China and 320 individuals in north China.</p><p><b>RESULTS</b>We inspected 10 alleles of HLA-DQB1 and got a series of comprehensive and accurate statistic data.</p><p><b>CONCLUSION</b>It is tested that HLA-DQB1*02, 05, 0601, 0602, 0603 gene frequencies are different obviously(P<0.05) between south and north Chinese. And those data will be useful to kinds of research associated with disease relevant and anthropology research.</p>

Susceptibility patterns and mechanisms of macrolide resistance in group B streptococcus isolates / 中华儿科杂志

<p><b>OBJECTIVE</b>To test the antibiotic susceptibility and study mechanisms of macrolide resistance in group B streptococcus isolates (GBS).</p><p><b>METHODS</b>The GBS investigated in this study included 140 and 47 colonizing strains isolated from vaginal or cervical swabs from pregnant women in Beijing (from 1994 to 1999) and Guangzhou obstetrics and gynecology hospitals (from 1999) and 6 invasive strains isolated from infants in Beijing Children's Hospital. Susceptibility to ampicillin, penicillin G, erythromycin, lincomycin, cephazolin, cefuroxime, cefoperazone was assessed by K-B disc diffusion. The mechanisms, methylation or efflux, of macrolide resistant GBS isolates, were analyzed by PCR for ermB and mefA genes.</p><p><b>RESULTS</b>Susceptibility testing revealed that none of the GBS isolates were resistant to beta-lactam drugs, but 17% isolates showed intermediate susceptibility to penicillin G and ampicillin. The rate of erythromycin resistance increased from 8% in 1998 to 16% in 1999 in Beijing, while the rate of lincomycin resistance increased from 20% to 28% in that period. However, 21 (45%) and 12 (26%) isolates were resistant to erythromycin and lincomycin, respectively in Guangzhou city where erythromycin resistance rate was higher than that in Beijing. Of 45 erythromycin resistant isolates, 20 (20/45, 44%) possessed the ermB gene and 13 (13/45, 29%) harbored the mefA gene; 6 isolates harbored both genes, 6 isolates had possessed neither ermB gene nor mefA gene.</p><p><b>CONCLUSION</b>The susceptibility of GBS isolates to penicillin G and ampicillin suggests use of penicillin G or ampicillin as a first-line drug in prophylactic treatment regimes against early-onset neonatal GBS disease. Erythromycin and lincomycin should not be recommended as the second-line antimicrobial in Beijing and Guangzhou city. The clinical relevance of macrolide resistant GBS in women treated with macrolides for intrapartum prophylaxis needs to be assessed. Ribosomal modification by a methylase encoded by erm gene may play a major role in the mechanisms of macrolide resistance of GBS isolates in China.</p>