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A Case Of Vero Cytotoxinproducing Escherichia Coli (VTEC)
Published in Meera Chand, John Holton, Case Studies in Infection Control, 2018
The culture isolated at GBRU from Case A and the cultures from Cases B and C submitted to GBRU from the local hospital laboratory were confirmed as Vero cytotoxin-producing E. coli (VTEC) O157 (also known as Shiga toxin-producing E. coli or STEC) and typed using phage typing (PT) and multilocus variable number tandem repeat (VNTR) analysis (MLVA). All three strains of phage typed as PT21/28. The MLVA profiles of each strain are shown in Table 24.1.
The Use of Subtyping
Published in Johan Giesecke, Modern Infectious Disease Epidemiology, 2017
The present leap are the different methods for ‘genetic fingerprinting’ which allow us to identify individual strains of bacteria or viruses by looking at specific sequences in their genomes – or at the entire genome. With techniques such as restriction-fragment length polymorphism (RFLP), pulse-field gel electrophoresis (PFGE) or multilocus variable-number tandem repeat analysis (MLVA), it is often possible to chart the separate clones of microbes within a population where several sources of the same pathogen are operating simultaneously. These techniques are rapidly becoming obsolete and being replaced by direct sequencing of the entire genome of the pathogen. The speed at which such whole genome sequencing (WGS) has been developed and made quicker, cheaper and more accessible in the last decade is amazing.
Salmonella
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
MLVA assesses the variability (in terms of nucleotide sequence and unit size) of the genetic entity called variable number tandem repeat (VNTR), which is present at multiple loci in the Salmonella genome. MLVA subtyping of Salmonella strains demonstrates serovar specificity, in comparison with PFGE, which is applicable to all serotypes.
Genotyping and molecular characterization of clinical Acinetobacter baumannii isolates from a single hospital in Southwestern Iran
Published in Pathogens and Global Health, 2020
Ahmad Farajzadeh Sheikh, Mohammad Savari, Effat Abbasi Montazeri, Saeed Khoshnood
For molecular typing, two multiplex PCRs were performed to selectively amplify the alleles of chaperone-subunit usher E (csuE), the outer membrane protein A (ompA), and the intrinsic carbapenemase (blaOXA-51-like) gene, and to determine the sequence groups and the corresponding major international clones (ICs) I–III according to Turton et al. [27]. The amplification reaction was carried out by using a thermal cycler (Mastercycler Eppendorf, Germany) with an initial denaturation at 94 °C for 3 min, followed by 30 cycles of 94 °C for 45 s, 57 °C for 45 s, and 72 °C for 1 min, and a final extension step was conducted at 72 °C for 5 min. The MLVA typing of A. baumannii isolates was carried out using the MLVA-8 scheme method designed by Pourcel et al. [13]. The MLVA-8 scheme profiles in each isolate were identified by the number of repeats estimated at each VNTR locus.
Bioburden and transmission of pathogenic bacteria through elevator channel during endoscopic retrograde cholangiopancreatography: application of multiple-locus variable-number tandem-repeat analysis for characterization of clonal strains
Published in Expert Review of Medical Devices, 2019
Masoumeh Azimirad, Masoud Alebouyeh, Amir Sadeghi, Elham Khodamoradi, Hamid Asadzadeh Aghdaei, Amir Houshang Mohammad Alizadeh, Mohammad Reza Zali
To compare genetic relatedness of P. aeruginosa strains, their MLVA profiles were determined. Accordingly, a panel containing 15 VNTR loci (in order of ms77, ms127, ms142, ms172, ms211, ms212, ms213, ms214, ms215, ms216, ms217, ms222, ms223, ms207, and ms209) was selected and allelic profiles corresponding to the number of repeats at each VNTR was measured based on the method described by Vu Thien et al. [21,22]. P. aeruginosa strain PAO1 was used as control for all the experiments. The conversion of PCR product sizes into repeat copy number was done based on MLVA alleles assignment table provided by Christine Pourcel (MLVAnet support site). A phylogenetic dendrogram was drawn based on the obtained MLVA profiles using Ward method (WEBPAGE).