Xiaoxia Tao

Centers for Disease Control and Prevention, Atlanta, MI, USA

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Publications (11)33.47 Total impact

  • Article: Detection of Mycoplasma pneumoniae by colorimetric loop-mediated isothermal amplification.
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    ABSTRACT: Mycoplasma pneumoniae (M. pneumoniae) is one of the most important pathogens that cause respiratory tract infection in children and adults. In this study, we describe a rapid and sensitive colorimetric loop mediated isothermal amplification (LAMP) method to detect M. pneumoniae. The specificity and sensitivity of this assay were detected with 21 common respiratory pathogens and 39 M. pneumoniae DNA. The sensitivity of LAMP was 100% among 39 M. pneumoniae isolates and the specificity was 100% among 9 members of other Mycoplasma and 12 common respiratory pathogens. The lowest detectable limit (LDL) of this assay was 102 copies, which detected by a series of standard M. pneumoniae DNA. To evaluate the clinical applicability of the LAMP assay, a total of 80 clinical samples were examined by conventional PCR, real-time PCR and the LAMP assays, respectively. The positive rates were 15.0%, 32.5% and 26.3%, respectively. This colorimetric LAMP assay demonstrated a high level of sensitivity comparable with that of conventional PCR for the detection of M. pneumoniae. It is a valuable method for simple, cost-effective and rapid detection of M. pneumoniae in the rural areas and basic clinical of China.
    Acta Microbiologica et Immunologica Hungarica 03/2013; 60(1):1-9. · 0.79 Impact Factor
  • Article: Multiple-Locus Variable-Number Tandem-Repeat Analysis of Acinetobacter baumannii in China: comparison with PFGE typing.
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    ABSTRACT: A panel of seven variable-number tandem repeats (VNTRs) markers was selected for Acinetobacter baumannii typing analysis (MLVA-7). Compared with pulsed-field gel electrophoresis (PFGE), MLVA-7 provided greater discrimination. We modified the criteria for MLVA complexes assignment proposed previously, and a remarkable congruence between MLVA-7 and PFGE-based strain clustering was observed.
    Journal of clinical microbiology 01/2013; · 4.16 Impact Factor
  • Article: Surveillance of Macrolide Resistant Mycoplasma pneumoniae in Beijing, China from 2008 to 2012.
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    ABSTRACT: Macrolide resistance rates of Mycoplasma pneumoniae in Beijing population were as high as 68.9%, 90.0%, 98.4%, 95.4% and 97.0% from 2008 to 2012, respectively. Common macrolide resistant mobile genetic elements were not detected with any isolate. These macrolide resistant isolates came from multiple clones rather than the same clone. No massive aggregation of a particular clone was found in specific period.
    Antimicrobial Agents and Chemotherapy 12/2012; · 4.84 Impact Factor
  • Article: Characterization of Staphylococcus aureus strains associated with food poisoning in Shenzhen, China.
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    ABSTRACT: To characterize isolates of Staphylococcus aureus that were associated with staphylococcal food poisoning between 2006 and 2009 in Shenzhen, Southern China, a total of 52 Staphylococcus aureus isolates from 11 outbreaks were analyzed by using multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE). PCR analysis was used to analyze the staphylococcal enterotoxin (SE) genes sea to sei, and antimicrobial susceptibility testing was also performed. ST6 was the most dominant sequence type (ST), constituting 63.5% (34/52) of all of the isolates in 7 outbreaks. The next most common ST was ST943, which constituted 23.1% (12/52) of the isolates that were collected from 3 outbreaks. t701, t091, and t2360 were the most predominant spa types, constituting 67.3% (35/52) of the isolates that were collected from 11 outbreaks. Three PFGE types, (types A, B, and C) were the most frequently observed types, constituting 84.6% (44/52) of all of the isolates. The enterotoxin gene that we detected most frequently was sea (45/52; 86.5%). Four SE gene profiles were observed, including sea (n = 45), sec-seh (n = 3), seb (n = 2), and seg-sei (n = 2). With respect to antibiotic resistance, penicillin resistance was the most common (96.2%; 50/52), followed by resistance to tetracycline (28.8%; 15/52). Approximately 30.8% (16/52) of the isolates were resistant to at least two antibiotics, and 7.7% (4/52) of the isolates were resistant to three or more drugs. The two predominant S. aureus lineages, (i) PFGE types A and B with ST6 and (ii) PFGE type C with ST943, were identified in the outbreaks.
    Applied and environmental microbiology 07/2012; 78(18):6637-42. · 3.69 Impact Factor
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    Article: Comparative genomics of Helicobacter pylori strains of China associated with different clinical outcome.
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    ABSTRACT: In this study, a whole-genome CombiMatrix Custom oligonucleotide tiling microarray with 90,000 probes covering six sequenced Helicobacter pylori (H. pylori) genomes was designed. This microarray was used to compare the genomic profiles of eight unsequenced strains isolated from patients with different gastroduodenal diseases in Heilongjiang province of China. Since significant genomic variation was found among these strains, an additional 76 H. pylori strains associated with different clinical outcomes were isolated from various provinces of China. These strains were tested by polymerase chain reaction to demonstrate this distinction. We identified several highly variable regions in strains associated with gastritis, gastric ulceration, and gastric cancer. These regions are associated with genes involved in the bacterial type I, type II, and type III R-M systems. They were also associated with the virB gene, which lies on the well-studied cag pathogenic island. While previous studies have reported on the diverse genetic characterization of this pathogenic island, in this study, we find that it is conserved in all strains tested by microarray. Moreover, a number of genes involved in the type IV secretion system, which is related to horizontal DNA transfer between H. pylori strains, were identified in the comparative analysis of the strain-specific genes. These findings may provide insight into new biomarkers for the prediction of gastric diseases.
    PLoS ONE 01/2012; 7(6):e38528. · 4.09 Impact Factor
  • Article: Antibiotic sensitivity of 40 Mycoplasma pneumoniae isolates and molecular analysis of macrolide-resistant isolates from Beijing, China.
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    ABSTRACT: MICs of eight antibiotics were detected with 40 Chinese Mycoplasma pneumoniae isolates. Thirty-eight isolates (95%) were macrolide resistant. Each macrolide-resistant isolate harbored an A2063G or A2064G point mutation in the 23S rRNA gene. All 40 isolates (100%) were type I strains, but they might have originated from different clones.
    Antimicrobial Agents and Chemotherapy 11/2011; 56(2):1108-9. · 4.84 Impact Factor
  • Article: Sequence analysis of the p1 adhesin gene of Mycoplasma pneumoniae in clinical isolates collected in Beijing in 2008 to 2009.
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    ABSTRACT: The p1 genes of 60 Mycoplasma pneumoniae clinical isolates were sequenced and compared to previously reported p1 gene sequences. An AGT trinucleotide variable-number tandem repeat was identified that ranged in copy number from 5 to 14 among the isolates. In addition, a novel p1 gene variant named 2c was identified in 6 of the isolates.
    Journal of clinical microbiology 06/2011; 49(8):3000-3. · 4.16 Impact Factor
  • Article: Increasing resistance in multiresistant methicillin-resistant Staphylococcus aureus clones isolated from a Chinese hospital over a 5-year period.
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    ABSTRACT: The aim was to study the changes in the antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) clones over a 5-year period (from 2000 to 2005) at a representative hospital in Beijing, China. A total of 100 randomly selected MRSA strains were analyzed using antimicrobial susceptibility testing, pulsed-field gel electrophoresis, spa typing, multilocus sequence typing, SCCmec typing, and PCR for the Panton-Valentine leukocidin virulence factor. Resistance to rifampin greatly increased from 32% (16/50) to 68% (34/50). High-level mupirocin-resistant isolates were found only in 2005, when four were identified. Intermediate susceptibly to quinupristin-dalfopristin increased from 22% (11/50) to 52% (26/50) between 2000 and 2005. The main antimicrobial resistance profiles changed from TC-GM-CI-EM-CM in 2000 to TC-GM-CI-EM-CM-RI in 2005. The main pulsed-field gel electrophoresis type changed from types C, L, and E in 2000 to types J, F, and N, respectively, in 2005. ST239-MRSA-III was the most predominant clone in 2000 and 2005, whereas ST5-MRSA-II was found only in 2005. There were increasing levels of antimicrobial resistance and epidemiological changes in the hospital-associated MRSA strains isolated in this facility between 2000 and 2005.
    Microbial drug resistance (Larchmont, N.Y.) 01/2011; 17(2):235-9. · 1.99 Impact Factor
  • Article: Clinical comparison of branched DNA and reverse transcriptase-PCR and nucleic acid sequence-based amplification assay for the quantitation of circulating recombinant form_BC HIV-1 RNA in plasma.
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    ABSTRACT: To investigate the correlation between three viral load assays for circulating recombinant form (CRF)_BC. Recent studies in HIV-1 molecular epidemiology, reveals that CRF_BC is the dominant subtype of HIV-1 virus in mainland China, representing over 45% of the HIV-1 infected population. The performances of nucleic acid sequence-based amplification (NASBA), branched DNA (bDNA) and reverse transcriptase polymerase chain reaction (RT-PCR) were compared for the HIV-1 viral load detection and quantitation of CRF_BC in China. Sixteen HIV-1 positive and three HIV-1 negative samples were collected. Sequencing of the positive samples in the gp41 region was conducted. The HIV-1 viral load values were determined using bDNA, RT-PCR and NASBA assays. Deming regression analysis with SPSS 12.0 (SPS Inc., Chicago, Illinois, USA) was performed for data analysis. Sequencing and phylogenetic analysis of env gene (gp41) region of the 16 HIV-1 positive clinical specimens from Guizhou Province in southwest China revealed the dominance of the subtype CRF_BC in that region. A good correlation of their viral load values was observed among three assays. Pearson's correlation between RT-PCR and bDNA is 0.969, Lg(VL)RT-PCR = 0.969 * Lg(VL)bDNA + 0.55; Pearson's correlation between RT-PCR and NASBA is 0.968, Lg(VL)RT-PCR = 0.968 * Lg(VL)NASBA + 0.937; Pearson's correlation between NASBA and bDNA is 0.980, Lg(VL)NASBA = 0.980 * Lg(VL)bDNA - 0.318. When testing with 3 different assays, RT-PCR, bDNA and NASBA, the group of 16 HIV-1 positive samples showed the viral load value was highest for RT-PCR, followed by bDNA then NASBA, which is consistent with the former results in subtype B. The three viral load assays are highly correlative for CRF_BC in China.
    AIDS (London, England) 01/2008; 21 Suppl 8:S27-32. · 4.91 Impact Factor
  • Article: [Serologic studies of Xinjiang hemorrhagic fever in Bachu county, 2001].
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    ABSTRACT: To investigate the situation of Xinjiang hemorrhagic fever (XHF) in patients who have been diagnosed as XHF by clinical methods and to predict the condition in people who were liable to infection and in the host-animals. Sera collected from XHF patients and some peasants under the risk of contracting the disease, followed by checking the specific antibody against XHF with IgG-ELISA and IgM capture ELISA, and XHF viral antigen with antigen capture ELISA. In addition, 80 sheep/goats serums were collected from two places where there were more XHF cases and specific IgG antibody against XHF checked by ELISA method. Positive rate of IgG and IgM antibodies were 39.62% (21/53) and 20.75% (11/53) respectively in the serums of patients; one patient's serum showed XHFV antigen positive by antigen capture ELISA. IgG antibody positive rate for peasants' sera was 21.05% (4/19), but IgM antibody detection showed negative for all sera. In sera from 80 sheep and goats, 70% (56/80) showed IgG positive. Results showed that XHF broke out in Bachu county from April to June 2001 while recessive infection of the disease remained serious.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 07/2002; 23(3):179-81.
  • Article: [Cultivation and serial propagation of a new rotavirus causing adult diarrhea in primary human embryo kidney cells].
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    ABSTRACT: To investigate the methodology of cultivation of the new rotavirus that causes adult diarrhea. 10% suspension of new rotavirus positive stool specimens in DMEM with 100 microgram/ml trypsin was made and centrifuged at the speed of 3 000 rpm for 10 minutes. The supernatant was filtered with 0.45 micrometer-pore-sized membrane filter, and the filtrate was incubated at 37 degrees C for 60 minutes. Primary human embryo kidney (PHEK) cells were prepared and seeded into roller tubes at the concentration of 1 ml odf cell suspension per tube. At 1 hour prior to inoculation, the PHEK cells were rinsed and refed with serum-free DMEM. Immediately before inoculation, the DMEM was decanted, and 200 microliter of prepared filtrate was inoculated into each tube. The tubes were incubated at 37 degrees C for 1 hour. At the end of 1 hour 800 microliter of DMEM containing trypsin (100 microgram per ml) were added to each tube. The tubes were placed in a roller tube apparatus at 37 degrees C for 3 days, removed and frozen-thawed once. 200 microliter of the cell culture fluids (CCF) were used for inoculation of each tube for next virus passage. Detection of new rotavirus from CCF was carried out by PAGE, IF, EM and IEM. New rotavirus was successfully isolated in cultured cells from 1 of 10 specimens. The isolated virus, designated J19, was propagated in PHEK cells for 28 passages. RNA patterns of J19 strain were identical to that of original new rotavirus inoculum and different from that of group A, B, C rotavirus. PHEK cells infected with the J19 strain were detected by IF. Infected cells reacted with convalescent antisera to the new rotavirus, but did not react with convalescent antisera to ADRV and hyperimmune antisera against group A, B rotavirus. Rotavirus particles were detected by EM, IEM in infected CCF of J19 strain. Other viral particles were not observed. The particles were aggregated with convalescent antisera to new rotavirus. We were successful in adapting a new rotavirus to serial propagation in PHEK cells. The J19 strain is a kind of new rotavirus different from group A, B, C rotavirus. This is the first report on the cultivation and propagation of the new rotavirus in cultured cells.
    Zhonghua yi xue za zhi 02/2002; 82(1):14-8.

Institutions

  • 2013
    • Centers for Disease Control and Prevention
      Atlanta, MI, USA
  • 2011–2012
    • Beijing Centers for Disease Control and Prevention
      Beijing, Beijing Shi, China
  • 2002
    • Chinese Center For Disease Control And Prevention
      Beijing, Beijing Shi, China