Complete Sequences and Characterization of Two Novel Plasmids Carrying aac(6')-Ib-cr and qnrS Gene in Shigella flexneri.

The complete sequences of two previously reported plasmids carrying plasmid-mediated quinolone resistance genes from Shigella flexneri in China have not been available. The present study using the p5-C3 assembly method revealed that (1) the plasmid pSF07201 with aac(6')-Ib-cr had 75,335 bp with antibiotic resistance genes CTX-M-3, TEM-1, and FosA3; (2) seven fragments of pSF07201 had more than 99% homology with the seven corresponding plasmids; (3) the other plasmid pSF07202 with qnrS had 47,669 bp with antibiotic resistance gene TEM-1 and 99.95% homology with a segment of pKF362122, which has the qnrS gene from location 162,490 to 163,146.

Epidemiologic characterization of 30 confirmed cases of human infection with avian influenza A(H7N9) virus in Hangzhou, China.

Background: We examined the clinical and epidemiological characteristics of 30 cases of human infection with avian influenza A(H7N9) virus in Hangzhou and investigated their external environments to provide evidence for contact tracing and disease prevention and control.

Methods: The cases confirmed from April 1 through May 1, 2013 were studied. Field epidemiologic surveys were conducted to collect the clinical and epidemiologic data.

Control of RNA stability by NrrF, an iron-regulated small RNA in Neisseria gonorrhoeae.

Regulation of gene expression by small noncoding RNAs (sRNAs) plays a critical role in bacterial response to physiological stresses. NrrF, a trans-acting sRNA in Neisseria meningitidis and Neisseria gonorrhoeae, has been shown in the meningococcus to control indirectly, in response to iron (Fe) availability, the transcription of genes encoding subunits of succinate dehydrogenase, a Fe-requiring enzyme. Given that in other organisms, sRNAs target multiple mRNAs to control gene expression, we used a global approach to examine the role of NrrF in controlling gonococcal transcription.

Spontaneous mutation frequency and molecular mechanisms of Shigella flexneri fluoroquinolone resistance under antibiotic selective stress.

The incidence of fluoroquinolone-resistant Shigella strains has risen rapidly, presumably in response to ciprofloxacin antibiotic stress. Understanding the molecular mechanisms underlying this resistance phenotype is critical to developing novel and effective therapeutic strategies. In this study, the frequency of ciprofloxacin-induced mutation was measured in antibiotic resistance genes (gyrA, gyrB, parC, parE, marOR, and marA) of Shigella flexneri.

Two adenovirus serotype 3 outbreaks associated with febrile respiratory disease and pharyngoconjunctival fever in children under 15 years of age in Hangzhou, China, during 2011.

Adenovirus serotype 3 and 7 outbreaks have occurred periodically in northern, eastern, and southern China since 1955, but there has been no report since the adenovirus serotype 7 outbreak first occurred in Hangzhou, China, in 1991. Here we explored the epidemiology and etiology of two adenovirus serotype 3 outbreaks in Hangzhou in 2011. One acute respiratory outbreak was found in Chun'an County, where a total of 371 cases were confirmed in 5 of 23 towns from 4 to 31 May 2011.

[Molecular characteristics and antibiotic resistances of Vibrio cholerae O1 isolates in Hangzhou in 2009].

Objective: To study the molecular characteristics and antibiotic resistances of Vibrio cholerae (V. cholerae) O1 isolates in Hangzhou in 2009.

Methods: The virulence genes ctxA and tcpA of the thirty V.

Vibrio cholerae O139 multiple-drug resistance mediated by Yersinia pestis pIP1202-like conjugative plasmids.

A conjugative plasmid, pMRV150, which mediated multiple-drug resistance (MDR) to at least six antibiotics, including ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole, was identified in a Vibrio cholerae O139 isolate from Hangzhou, eastern China, in 2004. According to partial pMRV150 DNA sequences covering 15 backbone regions, the plasmid is most similar to pIP1202, an IncA/C plasmid in an MDR Yersinia pestis isolate from a Madagascar bubonic plague patient, at an identity of 99.99% (22,180/22,183 nucleotides).

[Establishing a single-tube fluorescent bidirectional PCR method to detect the 609C/T polymorphism of NQO1 gene].

Objective: To develop a single-tube fluorescent bidirectional PCR method to detect the 609C/T polymorphism of NAD(P)H: quinone oxidoreductase 1 (NQO1) gene.

Methods: Two primers of NQO1 gene C609T locus were designed. Using these primers, a SYBR Green I fluorescent bidirectional PCR, combined with melting curve analysis of the PCR products, were optimized to differentiate the 609C/T polymorphisms in 191 samples of human genomic DNA.

[Preparation of armored RNA containing M gene of influenza H3N2].

Objective: To prepare the armored RNA containing M gene of influenza H3N2.

Methods: The vector pAR-1 was constructed from expression vector pET30b in which the bacteriophage MS2 DNA fragment, containing the genes for maturase and coat protein and the pac site, was inserted. The M gene fragment of influenza A was inserted into the HindIII site downstream of the pac site on the pAR-1, which formed a new recombinant plasmid pAR-2.

Preparation of armored RNA as a control for multiplex real-time reverse transcription-PCR detection of influenza virus and severe acute respiratory syndrome coronavirus.

The common respiratory viruses, including influenza A, influenza B, and newly emerging severe acute respiratory syndrome (SARS) viruses, may cause similar clinical symptoms. Therefore, differential diagnosis of these virus pathogens is frequently required for single clinical samples. In addition, there is an urgent need for noninfectious and stable RNA standards and controls for multivirus detection.

Molecular characteristics of class 1 and class 2 integrons and their relationships to antibiotic resistance in clinical isolates of Shigella sonnei and Shigella flexneri.

Objectives: To analyse the gene cassettes and determine the roles of class 1 and class 2 integrons in antibiotic-resistant strains of Shigella sonnei (n=31) and Shigella flexneri (n=33).

Methods: Various molecular techniques, including PCR and Southern-blotting analysis, were used to analyse various markers of class 1 and class 2 integrons in these 64 S. sonnei and S.

[Characteristics of virulence gene in Vibrio parahaemolyticus strains isolated from clinical patients and environment in Hangzhou, China].

Objectives: To investigate the characteristics of virulence gene in Vibrio parahaemolyticus strains isolated from clinical patients and environment in Hangzhou, China.

Methods: Thermostable direct hemolysin gene (tdh) and thermostable direct hemolysin-related hemolysin gene (trh) were determined in a total of 174 strains of V. parahaemolyticus isolated from patients and environment (seafood) in Hangzhou area by PCR.