scholarly journals Determination of investigation of the link between human and animal Brucella isolates in Iran using multiple-locus variable number tandem repeat method comprising 16 loci (MLVA-16)

2021 ◽  
Author(s):  
Shiva Mirkalantari ◽  
Faramarz Masjedi ◽  
Amraee Negar
Keyword(s):  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Multiple Locus

Determination of Sources of Escherichia coli on Beef by Multiple-Locus Variable-Number Tandem Repeat Analysis

2015 ◽  
Vol 78 (7) ◽  
pp. 1296-1302 ◽  
Author(s):  
XIANQIN YANG ◽  
FRANCES TRAN ◽  
MOHAMED K. YOUSSEF ◽  
COLIN O. GILL
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Conveyor Belt ◽  
Variable Number ◽  
Surface Type ◽  
Multiple Locus ◽  
E Coli ◽  
Repeat Analysis

The possible origin of Escherichia coli found on cuts and trimmings in the breaking facility of a beef packing plant was examined using multiple-locus variable-number tandem repeat analysis. Coliforms and E. coli were enumerated in samples obtained from 160 carcasses that would enter the breaking facility when work commenced and after each of the three production breaks throughout the day, from the conveyor belt before work and after each break, and from cuts and trimmings when work commenced and after each break. Most samples yielded no E. coli, irrespective of the surface types. E. coli was recovered from 7 (<5%) carcasses, at numbers mostly ≤1.0 log CFU/160,000 cm2. The log total numbers of E. coli recovered from the conveyor belt, cuts, and trimmings were mostly between 1 and 2 log CFU/80,000 cm2. A total of 554 E. coli isolates were recovered. Multiple-locus variable-number tandem repeat analysis of 327 selected isolates identified 80 distinct genotypes, with 37 (46%) each containing one isolate. However, 28% of the isolates were of genotypes that were recovered from more than one sampling day. Of the 80 genotypes, 65 and 2% were found in one or all four sampling periods throughout the day. However, they represented 23 and 14% of the isolates, respectively. Of the genotypes identified for each surface type, at least one contained ≥9 isolates. No unique genotypes were associated with carcasses, but 10, 17, and 19 were uniquely associated with cuts, trimmings, and the belt, respectively. Of the isolates recovered from cuts, 49, 3, and 19% were of genotypes that were found among isolates recovered from the belt, carcasses, or both the belt and carcasses, respectively. A similar composition was found for isolates recovered from trimmings. These findings show that the E. coli found on cuts and trimmings at this beef packing plant mainly originated from the conveyor belt and that small number of E. coli strains survived the daily cleaning and sanitation process, thus persisting in the plant.

scholarly journals Multiple-Locus Variable-Number Tandem Repeat Analysis of Dutch Bordetella pertussis Strains Reveals Rapid Genetic Changes with Clonal Expansion during the Late 1990s

2004 ◽  
Vol 186 (16) ◽  
pp. 5496-5505 ◽  
Author(s):  
Leo M. Schouls ◽  
Han G. J. van der Heide ◽  
Luc Vauterin ◽  
Paul Vauterin ◽  
Frits R. Mooi
Keyword(s):  
The Netherlands ◽  
Tandem Repeat ◽  
Bordetella Pertussis ◽  
Minimum Spanning Tree ◽  
Whooping Cough ◽  
Variable Number Tandem Repeat ◽  
Clonal Expansion ◽  
Variable Number ◽  
Multiple Locus ◽  
Repeat Analysis

ABSTRACT Bordetella pertussis, the causative agent of whooping cough, has remained endemic in The Netherlands despite extensive nationwide vaccination since 1953. In the 1990s, several epidemic periods have resulted in many cases of pertussis. We have proposed that strain variation has played a major role in the upsurges of this disease in The Netherlands. Therefore, molecular characterization of strains is important in identifying the causes of pertussis epidemiology. For this reason, we have developed a multiple-locus variable-number tandem repeat analysis (MLVA) typing system for B. pertussis. By combining the MLVA profile with the allelic profile based on multiple-antigen sequence typing, we were able to further differentiate strains. The relationships between the various genotypes were visualized by constructing a minimum spanning tree. MLVA of Dutch strains of B. pertussis revealed that the genotypes of the strains isolated in the prevaccination period were diverse and clearly distinct from the strains isolated in the 1990s. Furthermore, there was a decrease in diversity in the strains from the late 1990s, with a remarkable clonal expansion that coincided with the epidemic periods. Using this genotyping, we have been able to show that B. pertussis is much more dynamic than expected.

scholarly journals Genotyping Mycoplasma hyorhinis by multi-locus sequence typing and multiple-locus variable-number tandem-repeat analysis

2020 ◽  
Vol 249 ◽  
pp. 108836
Author(s):  
Dorottya Földi ◽  
Katinka Bekő ◽  
Orsolya Felde ◽  
Zsuzsa Kreizinger ◽  
Áron B. Kovács ◽  
...  
Keyword(s):  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Multi Locus Sequence Typing ◽  
Mycoplasma Hyorhinis ◽  
Multiple Locus ◽  
Repeat Analysis

scholarly journals Multiple-locus variable-number tandem repeat analysis for strain discrimination of non-O157 Shiga toxin-producing Escherichia coli

2016 ◽  
Vol 125 ◽  
pp. 70-80 ◽  
Author(s):  
Chris Timmons ◽  
Eija Trees ◽  
Efrain M. Ribot ◽  
Peter Gerner-Smidt ◽  
Patti LaFon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Shiga Toxin ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Multiple Locus ◽  
Repeat Analysis

Molecular typing of Francisella tularensis using multiple-locus variable-number tandem-repeat analysis

2014 ◽  
Vol 29 (1) ◽  
pp. 8-15 ◽  
Author(s):  
V. S. Timofeev ◽  
T. Yu. Kudryavtseva ◽  
A. N. Mokrievich ◽  
V. M. Pavlov ◽  
I. A. Dyatlov
Keyword(s):  
Francisella Tularensis ◽  
Tandem Repeat ◽  
Molecular Typing ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Multiple Locus ◽  
Repeat Analysis

Microbiological Effects of a Routine Treatment for Decontaminating Hide-On Carcasses at a Large Beef Packing Plant

2015 ◽  
Vol 78 (2) ◽  
pp. 256-263 ◽  
Author(s):  
XIANQIN YANG ◽  
MADHU BADONI ◽  
FRANCES TRAN ◽  
COLIN O. GILL
Keyword(s):  
Escherichia Coli ◽  
Tandem Repeat ◽  
Variable Number Tandem Repeat ◽  
Variable Number ◽  
Routine Treatment ◽  
Multiple Locus ◽  
E Coli ◽  
Repeat Analysis ◽  
Before And After

To investigate the microbiological effects of a hide-on carcass decontaminating treatment recently implemented at a beef packing plant, carcasses undergoing routine processing at the plant were sampled during successive periods in January/February, April/May, and September/October. During each period, samples were collected from carcasses before and after the decontamination of hide-on carcasses, after skinning, before decontamination of the skinned carcasses, and at the end of the carcass dressing process. At each stage of processing during each period, samples were obtained by swabbing an area of 1,000 cm2 on each of 25 carcasses. Aerobes, coliforms, and Escherichia coli were enumerated. In most samples, coliforms were predominantly E. coli. In all three periods, the log mean numbers of aerobes and E. coli recovered from hides before decontamination were between 6.6 and 6.8 and between 5.3 and 5.9 log CFU/1,000 cm2, respectively. The log mean numbers of aerobes recovered from decontaminated hides were 6.6 log CFU/1,000 cm2 in January/February and April/May but 5.4 log CFU/1,000 cm2 in September/October. The log total numbers of E. coli recovered from decontaminated hides in January/February and April/May were 2.4 and 3.8 log CFU/25,000 cm2, respectively, but no E. coli was recovered from such carcasses in September/October. Log total numbers of aerobes and E. coli recovered from skinned or dressed carcasses were mostly >4 and between 1 and 2 log CFU/25,000 cm2, respectively. Typing of 480 E. coli isolates by multiple-locus variable-number tandem repeat analysis (MLVA) identified 218 MLVA types. Most isolates recovered from carcasses in different periods or at different stages of processing were of different MLVA types. However, small numbers of MLVA types were recovered in more than one period or from both hides before and after decontamination and skinned or dressed carcasses. The findings show that the hide-decontaminating treatment disrupted the usual transfer of E. coli from hides to meat surfaces during carcass skinning.

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