scholarly journals Molecular typing of Shigella sonnei isolates circulating in Nanjing, China, 2007–2011

2014 ◽  
Vol 8 (12) ◽  
pp. 1525-1532 ◽  
Author(s):  
Tingting Cheng ◽  
Xiaochao Shi ◽  
Wei Yong ◽  
Jianping Wang ◽  
Guoxiang Xie ◽  
...  
Keyword(s):  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Pfge Pattern ◽  
Pulsed Field Gel Electrophoresis ◽  
Shigella Sonnei ◽  
Single Locus ◽  
Health Concern ◽  
Public Health Concern ◽  
Sequence Types ◽  
Vntr Analysis

Introduction: Shigellosis is a major public health concern worldwide. This study intended to assess the baseline genotyping data among local Shigella sonnei strains spanning over five years. Methodology: Fifty non-repeat clinical strains of S. sonnei isolated from stools of patients in different hospitals in Nanjing, China, were studied. Three subtyping tools, pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and multi-locus variable-number tandem-repeat (VNTR) analysis (MLVA), were used for routinely subtyping local S. sonnei. Results: DNA sequencing only identified two sequence types (STs) among the 50 isolates in the MLST profiles, whereas PFGE and MLVA both showed suitable discriminatory power and yielded 19 and 30 different patterns, respectively. The major PFGE pattern comprised 21 strains isolated from different years. A total of four complexes were identified by MLVA, with the isolates differing by a single locus (single-locus variants). Conclusions: The S. sonnei strains circulating in Nanjing, China, in 2007–2011 originated from different clones with a degree of diversity. Most of the clones were closely related to each other. Overall, the strains were distinguishable by PFGE and MLVA. MLVA based on eight selected VNTR loci represented a more favorable degree of discrimination than did PFGE and may be a reliable complement for PFGE for routine subtyping of S. sonnei. The problems of MLST in subtyping regarding S. sonnei were also demonstrated.

scholarly journals Comparison of Multilocus Variable-Number Tandem-Repeat Analysis with Multilocus Sequence Typing and Pulsed-Field Gel Electrophoresis for Enterococcus faecalis

2011 ◽  
Vol 60 (4) ◽  
pp. 335-339 ◽  
Author(s):  
EWA SADOWY ◽  
ALEKSANDRA SIEŃKO ◽  
WALERIA HRYNIEWICZ
Keyword(s):  
Enterococcus Faecalis ◽  
Gel Electrophoresis ◽  
Tandem Repeats ◽  
Diversity Index ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Pulsed Field Gel Electrophoresis ◽  
Discriminatory Power ◽  
Pulsed Field ◽  
High Discriminatory Power

Enterococcus faecalis represents recently an important etiological agent of health care-associated infections (HAIs) and there is a need for evaluation and comparison of typing methods available for this microorganism. We tested multilocus VNTR (variable-number tandem repeats) analysis (MLVA) on a well-characterized collection of 153 clinical isolates of E. faecalis, corresponding to 52 multilocus sequence types and 67 pulsed-field gel electrophoresis (PFGE) profiles. MLVA showed high discriminatory power, discerning 111 different types (diversity index equal 98.9%). The concordance MLVA/MLST and MLVA/PFGE was 0.95 and 0.74, respectively. High discriminatory power of MLVA indicates its utility for local epidemiology such as outbreak investigation, and for differentiation of clones defined by other methods.

An Outbreak of Salmonella enterica Serotype Litchfield Infection in Australia Linked to Consumption of Contaminated Papaya

2009 ◽  
Vol 72 (5) ◽  
pp. 1094-1098 ◽  
Author(s):  
ROBYN GIBBS ◽  
NEVADA PINGAULT ◽  
TERRY MAZZUCCHELLI ◽  
LYN O'REILLY ◽  
BRIAN MacKENZIE ◽  
...  
Keyword(s):  
Western Australia ◽  
Potable Water ◽  
Case Control Study ◽  
Variable Number Tandem Repeat ◽  
Case Control ◽  
Variable Number ◽  
Pulsed Field Gel Electrophoresis ◽  
Outbreak Strain ◽  
Repeat Analysis ◽  
Control Study

An outbreak of 26 cases of Salmonella Litchfield infection occurred in the states of Western Australia and Queensland between October 2006 and January 2007. A case-control study was conducted with 12 cases and 24 controls, and a significant association was found between illness and consumption of papaya (odds ratio, 32.8; 95% confidence interval, 2.71 to 883.5). Papaya samples were collected from 26 stores in Western Australia, and 9 of 38 samples were contaminated with Salmonella Litchfield. These samples had pulsed-field gel electrophoresis patterns and multilocus variable-number tandem-repeat analysis profiles indistinguishable from the outbreak strain. Three farms in Western Australia supplied the contaminated papaya, and two of these farms were inspected. Salmonella Litchfield was not detected in papaya samples, fungal sprays, or water samples from the farms; however, at one farm other serotypes of Salmonella were detected in untreated river water that was used for washing papaya. Only treated potable water should be used for washing fresh produce that is to be eaten raw.

scholarly journals Drug-resistant Mycobacterium tuberculosis and its genotypes isolated from an outbreak in western Thailand

2020 ◽  
Author(s):  
Janisara Rudeeaneksin ◽  
Benjawan Phetsuksiri ◽  
Chie Nakajima ◽  
Supranee Bunchoo ◽  
Krairerk Suthum ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Variable Number Tandem Repeat ◽  
Multidrug Resistant ◽  
Variable Number ◽  
Drug Resistant ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Extensively Drug Resistant ◽  
Mdr Tb ◽  
Vntr Analysis

Abstract Background Multidrug-resistant TB (MDR-TB) outbreaks have occurred in the Thamaka district, Kanchanaburi province in Thailand. Methods Seventy-two isolates, which included 7% mono-, 30.6% MDR and extensively drug-resistant TB (XDR-TB), were genotyped by spoligotyping, mycobacterial interspersed repetitive unit-variable-number tandem repeat (MIRU-VNTR) and single nucleotide polymorphism genotyping, and their drug resistance was analysed. Results The spoligotyping results showed that Beijing spoligo-international type (SIT)1 was predominant (n=38; 52.8%) while the remaining were non-Beijing sublineages (n=34). The MIRU-VNTR analysis showed that Beijing isolates, most of which belonged to the modern type (n=37), formed 5 clusters and 13 individual patterns. In katG, only mutation Ser315Thr was identified. In rpoB, Ser531Leu was predominant, except for His526Arg and Leu533Pro, which were found in two isolates. A cluster of 14 Beijing strains contained these common mutations and shared the MIRU-VNTR genotype with isolates in the Thamaka district that had spread previously. Two U SIT523 isolates contained the mutations A1400G in rrs and Asp94Gly in gyrA genes, indicating a spread of XDR-TB. Conclusions Most mutations were associated with drug resistance and the specific MDR Beijing and XDR-TB in U SIT523 isolates remain. This genotyping is a key tool for tracking TB transmission in the Thamaka district of Thailand.

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