Multilocus genetics to reconstruct aeromonad evolution
<p>Abstract</p> <p>Background</p> <p><it>Aeromonas</it> spp. are versatile bacteria that exhibit a wide variety of lifestyles. In an attempt to improve the understanding of human aeromonosis, we investigated whether clinical isolates displayed specific chara...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2012-04-01
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| Series: | BMC Microbiology |
| Online Access: | http://www.biomedcentral.com/1471-2180/12/62 |
| _version_ | 1818001365050327040 |
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| author | Roger Frédéric Marchandin Hélène Jumas-Bilak Estelle Kodjo Angeli Lamy Brigitte |
| author_facet | Roger Frédéric Marchandin Hélène Jumas-Bilak Estelle Kodjo Angeli Lamy Brigitte |
| author_sort | Roger Frédéric |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p><it>Aeromonas</it> spp. are versatile bacteria that exhibit a wide variety of lifestyles. In an attempt to improve the understanding of human aeromonosis, we investigated whether clinical isolates displayed specific characteristics in terms of genetic diversity, population structure and mode of evolution among <it>Aeromonas</it> spp. A collection of 195 <it>Aeromonas</it> isolates from human, animal and environmental sources was therefore genotyped using multilocus sequence analysis (MLSA) based on the <it>dnaK</it>, <it>gltA</it>, <it>gyrB</it>, <it>radA</it>, <it>rpoB</it>, <it>tsf</it> and <it>zipA</it> genes.</p> <p>Results</p> <p>The MLSA showed a high level of genetic diversity among the population, and multilocus-based phylogenetic analysis (MLPA) revealed 3 major clades: the <it>A. veronii</it>, <it>A. hydrophila</it> and <it>A. caviae</it> clades<it>,</it> among the eleven clades detected. Lower genetic diversity was observed within the <it>A. caviae</it> clade as well as among clinical isolates compared to environmental isolates. Clonal complexes, each of which included a limited number of strains, mainly corresponded to host-associated subsclusters of strains, i.e., a fish-associated subset within <it>A. salmonicida</it> and 11 human-associated subsets, 9 of which included only disease-associated strains. The population structure was shown to be clonal, with modes of evolution that involved mutations in general and recombination events locally. Recombination was detected in 5 genes in the MLSA scheme and concerned approximately 50% of the STs. Therefore, these recombination events could explain the observed phylogenetic incongruities and low robustness. However, the MLPA globally confirmed the current systematics of the genus <it>Aeromonas.</it></p> <p>Conclusions</p> <p>Evolution in the genus <it>Aeromonas</it> has resulted in exceptionally high genetic diversity. Emerging from this diversity, subsets of strains appeared to be host adapted and/or “disease specialized” while the <it>A. caviae</it> clade displayed an atypical tempo of evolution among aeromonads. Considering that <it>A. salmonicida</it> has been described as a genetically uniform pathogen that has adapted to fish through evolution from a variable ancestral population, we hypothesize that the population structure of aeromonads described herein suggested an ongoing process of adaptation to specialized niches associated with different degrees of advancement according to clades and clusters.</p> |
| first_indexed | 2024-04-14T03:33:27Z |
| format | Article |
| id | doaj.art-08b93079648b454392f9a474018001f0 |
| institution | Directory Open Access Journal |
| issn | 1471-2180 |
| language | English |
| last_indexed | 2024-04-14T03:33:27Z |
| publishDate | 2012-04-01 |
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| series | BMC Microbiology |
| spelling | doaj.art-08b93079648b454392f9a474018001f02022-12-22T02:14:52ZengBMCBMC Microbiology1471-21802012-04-011216210.1186/1471-2180-12-62Multilocus genetics to reconstruct aeromonad evolutionRoger FrédéricMarchandin HélèneJumas-Bilak EstelleKodjo AngeliLamy Brigitte<p>Abstract</p> <p>Background</p> <p><it>Aeromonas</it> spp. are versatile bacteria that exhibit a wide variety of lifestyles. In an attempt to improve the understanding of human aeromonosis, we investigated whether clinical isolates displayed specific characteristics in terms of genetic diversity, population structure and mode of evolution among <it>Aeromonas</it> spp. A collection of 195 <it>Aeromonas</it> isolates from human, animal and environmental sources was therefore genotyped using multilocus sequence analysis (MLSA) based on the <it>dnaK</it>, <it>gltA</it>, <it>gyrB</it>, <it>radA</it>, <it>rpoB</it>, <it>tsf</it> and <it>zipA</it> genes.</p> <p>Results</p> <p>The MLSA showed a high level of genetic diversity among the population, and multilocus-based phylogenetic analysis (MLPA) revealed 3 major clades: the <it>A. veronii</it>, <it>A. hydrophila</it> and <it>A. caviae</it> clades<it>,</it> among the eleven clades detected. Lower genetic diversity was observed within the <it>A. caviae</it> clade as well as among clinical isolates compared to environmental isolates. Clonal complexes, each of which included a limited number of strains, mainly corresponded to host-associated subsclusters of strains, i.e., a fish-associated subset within <it>A. salmonicida</it> and 11 human-associated subsets, 9 of which included only disease-associated strains. The population structure was shown to be clonal, with modes of evolution that involved mutations in general and recombination events locally. Recombination was detected in 5 genes in the MLSA scheme and concerned approximately 50% of the STs. Therefore, these recombination events could explain the observed phylogenetic incongruities and low robustness. However, the MLPA globally confirmed the current systematics of the genus <it>Aeromonas.</it></p> <p>Conclusions</p> <p>Evolution in the genus <it>Aeromonas</it> has resulted in exceptionally high genetic diversity. Emerging from this diversity, subsets of strains appeared to be host adapted and/or “disease specialized” while the <it>A. caviae</it> clade displayed an atypical tempo of evolution among aeromonads. Considering that <it>A. salmonicida</it> has been described as a genetically uniform pathogen that has adapted to fish through evolution from a variable ancestral population, we hypothesize that the population structure of aeromonads described herein suggested an ongoing process of adaptation to specialized niches associated with different degrees of advancement according to clades and clusters.</p>http://www.biomedcentral.com/1471-2180/12/62 |
| spellingShingle | Roger Frédéric Marchandin Hélène Jumas-Bilak Estelle Kodjo Angeli Lamy Brigitte Multilocus genetics to reconstruct aeromonad evolution BMC Microbiology |
| title | Multilocus genetics to reconstruct aeromonad evolution |
| title_full | Multilocus genetics to reconstruct aeromonad evolution |
| title_fullStr | Multilocus genetics to reconstruct aeromonad evolution |
| title_full_unstemmed | Multilocus genetics to reconstruct aeromonad evolution |
| title_short | Multilocus genetics to reconstruct aeromonad evolution |
| title_sort | multilocus genetics to reconstruct aeromonad evolution |
| url | http://www.biomedcentral.com/1471-2180/12/62 |
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