Identification of Variable-Number Tandem-Repeat (VNTR) Sequences in Acinetobacter pittii and Development of an Optimized Multiple-Locus VNTR Analysis Typing Scheme / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To develop a multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) assay for Acinetobacter pittii typing.</p><p><b>METHODS</b>Polymorphic VNTRs were searched by Tandem Repeats Finder. The distribution and polymorphism of each VNTR locus were analyzed in all the A. pittii genomes deposited in the NCBI genome database by BLAST and were evaluated with a collection of 20 well-characterized clinical A. pittii strains and one reference strain. The MLVA assay was compared with pulsed-field gel electrophoresis (PFGE) for discriminating A. pittii isolates.</p><p><b>RESULTS</b>Ten VNTR loci were identified upon bioinformatic screening of A. pittii genomes, but only five of them showed full amplifiability and good polymorphism. Therefore, an MLVA assay composed of five VNTR loci was developed. The typeability, reproducibility, stability, discriminatory power, and epidemiological concordance were excellent. Compared with PFGE, the new optimized MLVA typing scheme provided the same and even greater discrimination.</p><p><b>CONCLUSION</b>Compared with PFGE, MLVA typing is a faster and more standardized alternative for studying the genetic relatedness of A. pittii isolates in disease surveillance and outbreak investigation.</p>

Antimicrobial susceptibility of Streptococcus sp. to quinupristin-dalfopristin in China / 生物医学与环境科学（英文）

This study aimed to determine the in vitro activity of quinupristin-alfopristin against Streptococcus sp. isolated in China. This agent is not yet available for clinical use, but it has been tested against a high proportion of resistant Staphylococcus aureus strains. A total of 156 streptococcal isolates, which were recovered from various geographic areas and diseases, were tested using the Etest (AB Biodisk, Solna, Sweden). Quinupristin-alfopristin showed excellent activity against all of the tested streptococci isolates. These results provide useful data for the clinical use of quinupristin-alfopristin in China.

Rapid and high-throughput identification of recombinant bacteria with mass spectrometry assay / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To construct a rapid and high-throughput assay for identifying recombinant bacteria based on mass spectrometry.</p><p><b>METHODS</b>Matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) techniques were used to identify 12 recombinant proteins (10 of Yersinia pestis, 1 of Campylobacter jejuni and 1 of Helicobacter pylori). A classification model for the various phase of recombinant bacteria was established, optimized and validated, using MALDI-TOF MS-ClinProTools system. The differences in the peptide mass spectra were analyzed by using Biotyper and FlexAnalysis softwares.</p><p><b>RESULTS</b>Models of GA, SNN, and QC were established. After optimizing the parameters, the GA recognition model showed good classification capabilities: RC=100%, mean CVA=98.7% (the CVA was 96.4% in phase 1, 100% in phase 2, 98.4% in phase 3, and 100% in phase 4, respectively) and PPV=95%. This model can be used to classify the bacteria and their recombinant, which only requires 3.7×103 cells for analysis. The total time needed is only 10 min from protein extraction to reporting the result for one sample. Furthermore, this assay can automatically detect and test 96 samples concurrently. A total of 48 specific peaks (9, 16, 9, and 14 for the four stages, respectively) was found in the various phase of recombinant bacteria.</p><p><b>CONCLUSION</b>MALDI-TOF MS can be used as a fast, accurate, and high-throughput method to identify recombinant bacteria, which provide a new ideas not only for recombinant bacteria but also for the identification of mutant strains and bioterrorism pathogens.</p>

Molecular epidemiological characteristics of Streptococcus pyogenes strains involved in an outbreak of scarlet fever in China, 2011 / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate molecular characterization of streptococcus pyogenes isolates involved in an outbreak of scarlet fever in China in 2011.</p><p><b>METHODS</b>Seventy-four Streptococcal pyogenes involved in an outbreak of scarlet fever were isolated from pediatric patients in the areas with high incidence in China from May to August of 2011. Emm genotyping, pulsed-field gel electrophoresis (PFGE), superantigen (SAg) genes and antimicrobial susceptibility profiling were analyzed for these isolates.</p><p><b>RESULTS</b>A total of 4 different emm types were identified. Emm12 was the most prevalent type which contained four predominating PFGE patterns corresponding to four different virulence and superantigen profiles. Emm12 (79.7%) and emm1 (14.9%) accounted for approximately 94% of all the isolates. The speA gene was all negative in emm12 isolates and positive in emm1 isolates. All strains were resistant to erythromycin, and 89.4% of them were resistant to erythromycin, tracycline, and clindamycin simultaneously.</p><p><b>CONCLUSION</b>Several highly diversified clones with a high macrolide resistance rate comprise a predominant proportion of circulating strains, though no new emm type was found in this outbreak. The data provide a baseline for further surveillance of scarlet fever, which may contribute to the explanation of the outbreak and development of a GAS vaccine in China.</p>

Evaluation of a new real-time PCR assay for detection of Mycoplasma pneumoniae in clinical specimens / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To establish and evaluate a real-time PCR assay to detect Mycoplasma pneumoniae (M.pneumoniae) in clinical specimens.</p><p><b>METHODS</b>By analysing the whole p1 gene sequence of 60 M.pneumoniae clinical isolates in Beijing of China, an optimized real-time PCR assay (MpP1) using p1 gene conserved region was designed. The specificity and sensitivity of this assay were evaluated and compared with other two reported assays (RepMp1 and Mp181) using 40 positive and 100 negative clinical specimens.</p><p><b>RESULTS</b>The detection limit of the new assay was 8.1 fg (about 1∼3CFU) M.pneumoniae DNA. The sensitivity of MpP1, RepMp1, and Mp181 assays appeared to be 100%, 100%, and 85%, respectively.</p><p><b>CONCLUSION</b>MpP1 assay is suitable for the detection of M.pneumoniae in Chinese clinical specimens.</p>

Comparison of NucliSens HIV-1 QT and Amplicor HIV-1 monitor 1.5 in detecting HIV-1 viral load / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To compare the results of detecting HIV-1 load by using NucliSens HIV-1 QT and Amplicor HIV-1 monitor 1.5 assays.</p><p><b>METHODS</b>Eighty-two clinical samples were collected and HIV viral load was determined with the above-mentioned two methods.</p><p><b>RESULTS</b>The number of samples in which values obtained by NucliSens HIV-1 QT and Amplicor HIV-1 monitor 1.5 differed by <0.5 log10 RNA copies/ml and in which the viral load was undetectable accounted for 88.9 percent of the measures. The correlation coefficient between the two methods was 0.956 in 56 samples of Deltalog10 VL<0.5.</p><p><b>CONCLUSION</b>The results of HIV-1 viral load determination with the two methods are highly comparable.</p>

The epidemic characteristics and preventive measures of hemorrhagic fever with syndromes in China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To summarize and analyze the epidemic situation of hantaviruses including geographic distribution, types and prevalent intensity of epidemic areas of hantavirus for the last 30 years in China, and to discuss relative preventive measures.</p><p><b>METHODS</b>Collecting and analyzing the data of hantaviruses epidemics in China.</p><p><b>RESULTS</b>The annual number of cases of hantavirus disease rapidly increased from 3295 in 1970 to 115,804 in 1986 then sustained between 40,000 and 60,000 cases annually in the 1990's, and then decreased thereafter. The epidemic areas existed in all provinces except Qinhai and Xinjiang and there were the hospitalized cases of hantavirus disease reported in other provinces. In recent years, the prevalence of hantavirus infection had increased in some cities, and the seasonal distribution of the cases changed as well.</p><p><b>CONCLUSION</b>Data suggested that the new epidemic characteristics of hantaviruses had emerged in China suggesting that it was necessary to strengthen surveillance programs and to take comprehensive preventive measures for the control and prevention of hantaviruses in China.</p>