scholarly journals Use of Pulsed-Field Gel Electrophoresis for Molecular Epidemiologic and Population Genetic Studies ofMycobacterium tuberculosis †

1999 ◽  
Vol 37 (6) ◽  
pp. 1927-1931 ◽  
Author(s):  
Samir P. Singh ◽  
Hugh Salamon ◽  
Carol J. Lahti ◽  
Mehran Farid-Moyer ◽  
Peter M. Small
Keyword(s):  
Genetic Diversity ◽  
Molecular Epidemiology ◽  
Gel Electrophoresis ◽  
Population Biology ◽  
Rflp Analysis ◽  
Analytical Techniques ◽  
Restriction Enzymes ◽  
Pulsed Field Gel Electrophoresis ◽  
Molecular Biology Technique ◽  
Pulsed Field

Pulsed-field gel electrophoresis (PFGE) is a powerful molecular biology technique which has provided important insights into the epidemiology and population biology of many pathogens. However, few studies have used PFGE for the molecular epidemiology ofMycobacterium tuberculosis. A laboratory protocol was developed to determine the typeability, stability, and reproducibility of PFGE typing of M. tuberculosis. Formal data-analytical techniques were used to assess the genetic diversity elucidated by PFGE analyses using four separate restriction enzymes and by IS6110 RFLP analyses, as well as to assess the concordance among these typing methods. One hundred epidemiologically characterized clinical isolates of M. tuberculosis were genotyped with four different PFGE enzymes (AseI, DraI,SpeI, and XbaI), as well as by RFLP analysis with IS6110. Identical patterns were found among 34 isolates known to be genetically related, suggesting that the PFGE protocol is robust and reproducible. Among 66 isolates representing population-sampled cases, heterozygosity and information content dependency estimates indicate that all five genotyping systems capture quantitatively similar levels of genetic diversity. Nevertheless, comparisons between PFGE analyses and IS6110 typing reveals that PFGE provided more discrimination among isolates with fewer than five copies of IS6110 and less clustering in isolates with five or more copies. The comparisons confirm the hypothesis that the resolution of IS6110 RFLP genotyping is dependent upon the number of IS6110 elements in the genome of isolates. The general concordance among the results obtained with four independent enzymes suggests that M. tuberculosis is a clonal organism. The availability of a robust genotyping technique largely independent of repetitive elements has implications for the molecular epidemiology of M. tuberculosis.

Construction of a genomic map ofMoraxella (Branhamella) catarrhalisATCC 25238 and physical mapping of virulence-associated genes

1999 ◽  
Vol 45 (4) ◽  
pp. 299-303 ◽  
Author(s):  
K T Nguyen ◽  
E J Hansen ◽  
M A Farinha
Keyword(s):  
Gel Electrophoresis ◽  
Moraxella Catarrhalis ◽  
Southern Hybridization ◽  
Physical Map ◽  
Outer Membrane Proteins ◽  
Restriction Enzymes ◽  
Pulsed Field Gel Electrophoresis ◽  
Respiratory Pathogens ◽  
Circular Chromosome ◽  
Pulsed Field

A physical genome map of the Moraxella catarrhalis type strain (ATCC 25238) has been constructed using pulsed field gel electrophoresis. Macrorestriction analyses of the genome of M. catarrhalis were performed by digestion with the restriction enzymes SmaI, NotI, and RsrII, which cleave the single circular chromosome into 9, 10, and 6 fragments, respectively. The chromosomal fragments generated by pulsed field gel electrophoresis were converted to a linkage map utilizing a combination of partial digestions, and cross-hybridizations. Moraxella catarrhalis, like a number of other respiratory pathogens, has a relatively small genome estimated at 1750 kilobase pairs or about 40% of the size of the Escherichia coli genome. The locations of the four ribosomal RNA operons (rrnLS) were determined by Southern hybridization and by digestion with I-CeuI endonuclease. A number of genes involved in virulence have been placed onto the physical map by Southern hybridization including those encoding the predominant outer-membrane proteins and the chromosomal gene encoding beta-lactamase.Key words: Moraxella catarrhalis, physical map, genome analysis, pulsed-field gel electrophoresis, virulence.

scholarly journals Investigation of genetic diversity of Salmonella enterica strains isolated from patients by Pulsed Field Gel Electrophoresis

2011 ◽  
Vol 5 (S1) ◽  
Author(s):  
Mohsen Ghafari ◽  
Bita Bakhshi ◽  
Mohamad Reza Pour Shafi ◽  
Nour Amir Mozafari ◽  
Mona Salimi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Pulsed Field Gel Electrophoresis ◽  
Pulsed Field

scholarly journals Association of IS1016 with the hia Adhesin Gene and Biotypes V and I in Invasive Nontypeable Haemophilus influenzae

2008 ◽  
Vol 76 (11) ◽  
pp. 5221-5227 ◽  
Author(s):  
Sarah W. Satola ◽  
Brooke Napier ◽  
Monica M. Farley
Keyword(s):  
Genetic Diversity ◽  
Haemophilus Influenzae ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Division I ◽  
Emerging Infections ◽  
Nontypeable Haemophilus Influenzae ◽  
Insertion Element ◽  
Pulsed Field ◽  
Slide Agglutination

ABSTRACT A subset of invasive nontypeable Haemophilus influenzae (NTHI) strains has evidence of IS1016, an insertion element associated with division I H. influenzae capsule serotypes. We examined IS1016-positive invasive NTHI isolates collected as part of Active Bacterial Core Surveillance within the Georgia Emerging Infections Program for the presence or absence of hmw1 and hmw2 (two related adhesin genes that are common in NTHI but absent in encapsulated H. influenzae) and hia (homologue of hsf, an encapsulated H. influenzae adhesin gene). Isolates were serotyped using slide agglutination, confirmed as NTHI strains using PCR capsule typing, and biotyped. Two hundred twenty-nine invasive NTHI isolates collected between August 1998 and December 2006 were screened for IS1016; 22/229 (9.6%) were positive. Nineteen of 201 previously identified IS1016-positive invasive NTHI isolates collected between January 1989 and July 1998 were also examined. Forty-one IS1016-positive and 56 randomly selected IS1016-negative invasive NTHI strains were examined. The hia adhesin was present in 39 of 41 (95%) IS1016-positive NTHI strains and 1 of 56 (1.8%) IS1016-negative NTHI strains tested; hmw (hmw1, hmw2, or both) was present in 50 of 56 (89%) IS1016-negative NTHI isolates but in only 5 of 41 (12%; all hmw2) IS1016-positive NTHI isolates. IS1016-positive NTHI strains were more often biotype V (P < 0.001) or biotype I (P = 0.04) than IS1016-negative NTHI strains, which were most often biotype II. Pulsed-field gel electrophoresis revealed the expected genetic diversity of NTHI with some clustering based on IS1016, hmw or hia, and biotypes. A significant association of IS1016 with biotypes V and I and the presence of hia adhesins was found among invasive NTHI. IS1016-positive NTHI strains may represent a unique subset of NTHI strains, with characteristics more closely resembling those of encapsulated H. influenzae.

scholarly journals Molecular epidemiology of Salmonella enteritidis phage type 1b and 6a isolates in Portugal

2003 ◽  
Vol 131 (1) ◽  
pp. 607-612 ◽  
Author(s):  
A. R. SOARES ◽  
J. MACHADO
Keyword(s):  
Molecular Epidemiology ◽  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Genomic Dna ◽  
Salmonella Enteritidis ◽  
Phage Type ◽  
Pulsed Field Gel Electrophoresis ◽  
Pulsed Field ◽  
Main Pattern

Salmonella enterica serotype Enteritidis is an important serovar comprising 76% of salmonella isolates in Portugal in 2001.For better understand the epidemiology of salmonellosis, a total of 47 isolates of S. Enteritidis phage type (PT) 1b and 6a were analysed by pulsed-field gel electrophoresis (PFGE) and genomic DNA was subjected to macro restriction with XbaI. For PT1b isolates, only three different patterns were observed, and PT6a showed a total of 10 digestion patterns. Curiously, the main pattern among PT1b isolates seams quite similar to main pattern of PT6a isolates, but when the two patterns were analysed with Bionumerics, we observed that they exhibited some differences. It was concluded that, in 2001, there was one predominant pattern for PT1b and PT6a and, possibly, we were in presence of clonal strains that exists all over the country.

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