Comparison of multilocus variable-number tandem repeat analysis and pulsed-field gel electrophoresis in molecular subtyping of Salmonella enterica serovars Paratyphi A.

Salmonella enterica serotype Paratyphi A is a highly clonal organism; pulsed-field gel electrophoresis (PFGE) is insufficient in discriminating isolates. A multilocus variable-number tandem repeat analysis (MLVA) was developed, and its usefulness in discriminating isolates was compared. PFGE analysis with XbaI and BlnI discriminated 55 isolates into 14 types, with a discriminatory index (DI) of 0.

Development and evaluation of multilocus variable number tandem repeat analysis for fine typing and phylogenetic analysis of Salmonella enterica serovar Typhimurium.

We identified 16 variable number tandem repeat (VNTR) loci for Salmonella enterica serovar Typhimurium. These VNTRs were evaluated with panels of 183 diverse isolates, 203 closely related isolates and 54 isolates from seven outbreaks. The evaluations revealed that five of the 16 VNTRs had diversity values greater than 0.

Multilocus variable-number tandem repeat analysis for molecular typing and phylogenetic analysis of Shigella flexneri.

Background: Shigella flexneri is one of the causative agents of shigellosis, a major cause of childhood mortality in developing countries. Multilocus variable-number tandem repeat (VNTR) analysis (MLVA) is a prominent subtyping method to resolve closely related bacterial isolates for investigation of disease outbreaks and provide information for establishing phylogenetic patterns among isolates. The present study aimed to develop an MLVA method for S.

Identification of prophage gene z2389 in Escherichia coli EDL933 encoding a DNA cytosine methyltransferase for full protection of NotI sites.

Pulsed-field gel electrophoresis (PFGE) analysis revealed that the genomes of some pathogenic Escherichia coli O157:H7 strains, including EDL933, were resistant to NotI digestion. An amino acid sequence comparison suggested that the z2389 gene carried on prophage CP-933R in strain EDL933 is likely to encode a C(5)-cytosine methyltransferase. The z2389-equivalent gene was found in the NotI-resistant strains tested, but it was not detected in the NotI-susceptible strains.

Utility of multilocus variable-number tandem-repeat analysis as a molecular tool for phylogenetic analysis of Shigella sonnei.

A panel of 916 isolates, including 703 closely related IST1 isolates, were characterized by inter-IS1 spacer typing (IST), pulsed-field gel electrophoresis (PFGE), and multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) to evaluate the utility of MLVA as a molecular tool for the phylogenetic analysis of Shigella sonnei. The global phylogenetic patterns determined by IST, PFGE, and MLVA were concordant. MLVA was carried out using 26 VNTR loci with a range of degrees of variability.

Multilocus variable-number tandem-repeat analysis for molecular typing of Shigella sonnei.

A multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) method was developed and evaluated for the subtyping of Shigella sonnei isolates. A total of 26 VNTR loci were identified by exploring the repeat sequence loci in the genomic sequences of S. sonnei strains Ss046 and 53G and by testing 536 isolates that had previously been characterized by pulsed-field gel electrophoresis (PFGE).

Epidemiology and evolution of genotype and antimicrobial resistance of an imported Shigella sonnei clone circulating in central Taiwan.

Shigella sonnei replaced Shigella flexneri to become the predominant species for shigellosis in 2001 to 2003 in central Taiwan. A total of 425 S. sonnei isolates collected from 1996 to 2004 were available for characterization by pulsed-field gel electrophoresis (PFGE), inter-IS1 spacer typing (IST), and antimicrobial susceptibility testing.

Identification of species of Abiotrophia, Enterococcus, Granulicatella and Streptococcus by sequence analysis of the ribosomal 16S-23S intergenic spacer region.

The feasibility of sequence analysis of the ribosomal 16S-23S intergenic spacer region (ITS) was evaluated for identification of 24 species of Streptococcus, one species of Abiotrophia, 18 species of Enterococcus and three species of Granulicatella. As GenBank currently lacks ITS sequence entries for many species of these four genera, the ITS sequences of 38 type strains were first sequenced and submitted to GenBank to facilitate species identification of these genera. Subsequently, the ITS sequences of 217 strains (84 reference strains and 133 clinical isolates) were determined and species identification was made by blast search for homologous sequences in public databases.

Array-based identification of species of the genera Abiotrophia, Enterococcus, Granulicatella, and Streptococcus.

Some species of enterococci and streptococci are difficult to differentiate by phenotypic traits. The feasibility of using an oligonucleotide array for identification of 11 viridans group streptococci was previously established. The aim of this study was to expand the array to identify species of Abiotrophia (1 species), Enterococcus (18 species), Granulicatella (3 species), and Streptococcus (31 species and 6 subspecies).