Clonal dynamics ofEscherichia coli in its natural habitat

Ts, Whittam

doi:10.1007/bf02309616

Cited by 80 publications

(78 citation statements)

References 32 publications

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“…Further, the clones isolated from the environment were genetically distinct from those isolated from the host population. These studies suggest that the clonal composition of E. coli communities changes substantially during the transition from the host to the external environment (Whittam, 1989).…”

Section: Figmentioning

confidence: 92%

“…Although the authors observed linkage disequilibrium for some pairwise locus comparisons, a multi-locus analysis of their data failed to reveal linkage disequilibrium among the 159 haplotypes (Gordon 1997). Whittam (1989) studied E. coli isolated from domestic birds and the litter on which the birds were raised. Only 10 % of the 113 distinct clones isolated were recovered from both habitats.…”

Section: Figmentioning

confidence: 99%

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Geographical structure and host specificity in bacteria and the implications for tracing the source of coliform contamination

2001

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OverviewThis mini-review presents the results of recent studies examining the extent to which among-population variation accounts for the genetic diversity of Escherichia coli and other members of the Enterobacteriaceae. The available population genetic data for E. coli are discussed in relation to an issue perceived to be of public health importance -the coliform contamination of water and efforts to trace the source of such contamination. For E. coli, the data suggest that geographical structure or host specificity accounts for little of the observed genetic diversity. Furthermore, the evidence indicates that there is little temporal stability in the clonal composition of E. coli populations. Consequently, most of the assumptions implicit in any programme attempting to identify the source of coliform contamination that focuses on commensal isolates of E. coli appear to be invalid. Other species of enteric bacteria appear to exhibit greater host specificity and geographical structure. The results of recent studies concerning the distribution of virulence factors among the clonal lineages of E. coli are highlighted and discussed in regard to alternative strategies for tracing the source of coliform contamination.

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Section: Figmentioning

confidence: 92%

Section: Figmentioning

confidence: 99%

Geographical structure and host specificity in bacteria and the implications for tracing the source of coliform contamination

2001

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“…of studied loci. The clonal diversity was measured by Whittam´s (Whittam 1989) index which is equal to: d = n ( 1-Σ Xi 2 )/( n-1), where Xi = frequency of each zymodeme and n = no. of stocks.…”

Section: Methodsmentioning

confidence: 99%

Isoenzyme profiles of Trypanosoma cruzi stocks from different areas of Paraguay

Acosta¹,

Samudio²,

López³

et al. 2001

Mem. Inst. Oswaldo Cruz

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“…Notable exceptions to the observed bias towards human isolates do exist but they are few in number (Routman et af., 1985;Whittam, 1989). An additional major bias present in many previous studies has been their basis on Abbreviations: ETs, electrophoretic types; MLEE, multi-locus enzyme electrophoresis; RAPD, randomly amplified polymorphic DNA.…”

Section: Introductionmentioning

confidence: 99%

The genetic structure of Escherichia coli populations in feral house mice

Gordon

1997

Microbiology

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Escherichia coli was isolated from feral house mice (Mus domesticus) during the course of a mouse plague in the state of Victoria, Australia. Two farms were sampled over a period of 7 months and a total of 447 isolates were collected. The isolates were characterized using the techniques of randomly amplified polymorphic DNA and multi-locus enzyme electrophoresis. The mean genetic diversity of this E. coli population (H = 024) was found to be substantially lower than the diversity of an E. coli population reported elsewhere for a single human host. Analysis of the allozyme data revealed that there were significant differences in the relative abundance of genotypes between the two localities sampled and among sample dates. Overall, however, spatial and temporal effects accounted for less than 5% of the genotypic diversity. Allele frequencies and the relative abundance of the more common genotypes did not differ between male and female hosts. The number of genotypes and genotype diversity increased as the age of the host increased, suggesting that the mice are continuing to acquire new E. coli clones throughout their life. The frequency of some alleles changed with respect to host age, which indicates that clone acquisition may not be a random process. It is argued that the low level of genetic diversity observed in this population of E. coli reflects the boom and bust nature of mouse population density in this region of Australia.

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Clonal dynamics ofEscherichia coli in its natural habitat

Cited by 80 publications

References 32 publications

Geographical structure and host specificity in bacteria and the implications for tracing the source of coliform contamination

Geographical structure and host specificity in bacteria and the implications for tracing the source of coliform contamination

Isoenzyme profiles of Trypanosoma cruzi stocks from different areas of Paraguay

The genetic structure of Escherichia coli populations in feral house mice

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