Genetic diversity and population structure of Aeromonas hydrophila, Aer. bestiarum, Aer. salmonicida and Aer. popoffii by multilocus enzyme electrophoresis (MLEE)

2004 ◽  
Vol 6 (3) ◽  
pp. 198-208 ◽  
Author(s):  
David Minana-Galbis ◽  
Maribel Farfan ◽  
M. Carme Fuste ◽  
J. Gaspar Loren
2001 ◽  
Vol 183 (2) ◽  
pp. 736-744 ◽  
Author(s):  
Núria Rius ◽  
M. Carme Fusté ◽  
Caterina Guasp ◽  
Jorge Lalucat ◽  
José G. Lorén

ABSTRACT Genetic diversity and genetic relationships among 42Pseudomonas stutzeri strains belonging to several genomovars and isolated from different sources were investigated in an examination of 20 metabolic enzymes by multilocus enzyme electrophoresis analysis. Forty-two distinct allele profiles were identified, indicating that all multilocus genotypes were represented by a single strain. All 20 loci were exceptionally polymorphic, with an average of 15.9 alleles per locus. To the best of our knowledge, thisP. stutzeri sample exhibited the highest mean genetic diversity (H = 0.876) found to date in all bacterial species studied by multilocus enzyme electrophoresis. A high frequency of occurrence of null alleles was identified. The index of association (IA ) for the P. stutzeri strains analyzed was 1.10. The IA values were always significantly different from zero for all subgroups studied, including clinical and environmental isolates and strains classified as genomovar 1. These results suggest that the population structure of P. stutzeri is strongly clonal, indicating that there is no significant level of assortative recombination that might destroy linkage disequilibrium.


Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2891-2900 ◽  
Author(s):  
Marco Scortichini ◽  
Emanuela Natalini ◽  
Luca Angelucci

To assess the genetic diversity and genetic relationships of Pseudomonas avellanae, the causative agent of hazelnut decline, a total of 102 strains, obtained from central Italy (provinces of Viterbo and Rome) and northern Greece, were studied using multilocus enzyme electrophoresis (MLEE). Their allelic variation in 10 loci was determined. All loci were polymorphic and 53 electrophoretic types (ETs) were identified from the total sample. The mean genetic diversity (H) was 0·65 and this value ranged from 0·37 for the least polymorphic to 0·82 for the most polymorphic locus. The dendrogram originated from MLEE data indicated two main groups of ETs, A and B. The groups do not appear to be correlated to the geographic origin of the strains, although all the ETs from northern Greece clustered into subgroup B1. Pseudomonas syringae pv. actinidiae and P. syringae pv. theae, included in the analysis as outgroups, clustered apart. The index of association (I A) for P. avellanae was 0·90. The I A values were always significantly different from zero for the population subsets studied and no epidemic structure was found. These results would indicate that the population structure of P. avellanae is clonal either in northern Greece or in central Italy. The recent outbreaks of the bacterium in new areas of hazelnut cultivation would explain the current clonal structure that is persisting over decades.


1996 ◽  
Vol 116 (1) ◽  
pp. 41-49 ◽  
Author(s):  
M. M. Feizabadi ◽  
I. D. Robertson ◽  
D. V. Cousins ◽  
D. Dawson ◽  
W. Chew ◽  
...  

SummaryGenetic relationships amongst 115 mainly Australian isolates ofMycobacterium aviumwere assessed using multilocus enzyme electrophoresis (MEE). The isolates were divided into 58 electrophoretic types (ETs), with a mean genetic diversity of 0·29. Isolates from humans were closely related to but distinct from those cultured from birds, whilst some porcine isolates belonged to the same ETs as certain human isolates. Pulsed field gel electrophoresis (PFGE) was used to differentiate related isolates, and those from birds and some from other animals, including pigs, were distinguished from the human isolates. The results of MEE and PFGE suggested that certain strains ofM. aviummay be transmitted between birds and pigs, but there was no clear evidence of transmission to humans. The serovar of theM. aviumisolates was not obviously related to their ET assignment or their PFGE type.


1992 ◽  
Vol 108 (1) ◽  
pp. 31-38 ◽  
Author(s):  
C. L. Poh ◽  
J. C. Ocampo ◽  
G. K. Loh

Multilocus enzyme electrophoretic analysis was employed to assess the genetic relatedness ofNeisseria gonorrhoeae. Based on the diversity of electromorphs at 9 enzyme loci, 16 electrophoretic types (ETs) were estabilished amongst the 65 isolates. The average number of alleles per enzyme locus was 1·7 and the mean genetic diversity per locus was 0·212. The majority of isolates belonged to either ET1 (32·3%) or ET2 (16·9%). No specific correlation of ETs was seen with serovars as the major types, ETs 1 and 2, were found distributed amongst the various serovars. Major serovars such as Bacjk (IB-1/2) and Bajk (IB-3/6) were each represented by 6 or 8 ETs respectively. Analysis of the genetic relationships of ETs to each other showed some clustering of subgroups that were more closely related than others.


2002 ◽  
Vol 184 (5) ◽  
pp. 1304-1313 ◽  
Author(s):  
M. Farfán ◽  
D. Miñana-Galbis ◽  
M. C. Fusté ◽  
J. G. Lorén

ABSTRACT Comparative analysis of gene fragments of six housekeeping loci, distributed around the two chromosomes of Vibrio cholerae, has been carried out for a collection of 29 V. cholerae O139 Bengal strains isolated from India during the first epidemic period (1992 to 1993). A toxigenic O1 ElTor strain from the seventh pandemic and an environmental non-O1/non-O139 strain were also included in this study. All loci studied were polymorphic, with a small number of polymorphic sites in the sequenced fragments. The genetic diversity determined for our O139 population is concordant with a previous multilocus enzyme electrophoresis study in which we analyzed the same V. cholerae O139 strains. In both studies we have found a higher genetic diversity than reported previously in other molecular studies. The results of the present work showed that O139 strains clustered in several lineages of the dendrogram generated from the matrix of allelic mismatches between the different genotypes, a finding which does not support the hypothesis previously reported that the O139 serogroup is a unique clone. The statistical analysis performed in the V. cholerae O139 isolates suggested a clonal population structure. Moreover, the application of the Sawyer's test and split decomposition to detect intragenic recombination in the sequenced gene fragments did not indicate the existence of recombination in our O139 population.


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