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Comparative Study
. 2013 Jan;79(2):601-9.
doi: 10.1128/AEM.02728-12. Epub 2012 Nov 9.

Comparative analysis of Leptospira strains isolated from environmental soil and water in the Philippines and Japan

Affiliations
Comparative Study

Comparative analysis of Leptospira strains isolated from environmental soil and water in the Philippines and Japan

Mitsumasa Saito et al. Appl Environ Microbiol. 2013 Jan.

Abstract

There have been few reports on the epidemiological analysis of environmental Leptospira isolates. This is probably because the isolation of leptospires from the environment was usually unsuccessful due to the overgrowth of contaminants and the slow growth of Leptospira. In this study, we collected a total of 88 samples of soil and water from three sites: Metro Manila and Nueva Ecija, Philippines (an area where Leptospira is now endemic), and Fukuoka, Japan (an area where Leptospira was once endemic). We succeeded in isolating Leptospira from 37 samples by using the novel combination of five antimicrobial agents reported in 2011. The frequencies of positive isolation of Leptospira in the Philippines and Japan were 40 and 46%, respectively. For Leptospira-positive samples, five colonies from each sample were isolated and analyzed by pulsed-field gel electrophoresis (PFGE). The isolates from each area showed their respective characteristics in phylogenetic trees based on the PFGE patterns. Some isolates were closely related to each other across borders. Based on 16S rRNA gene-based phylogenetic analysis, four isolates in Fukuoka were identified as a pathogenic species, L. alstonii; however, its virulence had been lost. One isolate from Nueva Ecija was identified as the intermediate pathogenic species Leptospira licerasiae. Most of the isolates from the environment belonged to nonpathogenic Leptospira species. We also investigated the strain variation among the isolates in a puddle over 5 months. We demonstrated, using PFGE analysis, that Leptospira survived in the wet soil on dry days and appeared in the surface water on rainy days. These results showed that the soil could be a reservoir of leptospires in the environment.

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Figures

Fig 1
Fig 1
PFGE patterns of Leptospira isolated from three environmental water samples: ES-1 (A), ES-56 (B), and ES-96 (C). Chromosomal DNA of isolates was digested with the NotI restriction endonuclease. Lanes: M, bacteriophage lambda concatemer molecular size marker; 1 to 5, PFGE patterns of five Leptospira strains isolated from each sample.
Fig 2
Fig 2
Phylogenetic tree based on PFGE fingerprint patterns showing the positions of 37 isolates (23 from the Philippines and 14 from Japan) and 19 reference strains. The patterns of isolates from environmental samples were categorized into seven clusters (clusters A to G). Similarity between patterns was calculated by using the Dice index. The data were sorted by the UPGMA method. Band comparison settings of 1.2% optimization and 1% position tolerance were used.
Fig 3
Fig 3
Neighbor-joining phylogenetic tree based on 16S rRNA gene sequence analysis showing the phylogenetic position of the 42 isolates (27 from the Philippines and 15 from Japan). The tree was rooted with 16S rRNA gene of Leptonema illini. GenBank accession numbers are shown in parentheses.
Fig 4
Fig 4
Influence of moisture content and pH of 15 soil samples on Leptospira isolation. The moisture content of 15 soil samples ranged from 3.5 to 42.8. The pH values ranged from 6.2 to 7.2. Six samples were Leptospira positive (●くろまる), whereas nine samples were Leptospira negative (○しろまる).
Fig 5
Fig 5
PFGE patterns of Leptospira strains isolated from a rain puddle on 30 June 2011 (A), 16 July 2011 (B), and 14 December 2011 (C). Chromosomal DNA from isolates was digested with NotI restriction endonuclease. Lanes 1 to 5, PFGE patterns of five isolates from each sample. The three PFGE patterns were named I, II, and III and are indicated below each fingerprint. MC, moisture content.

References

    1. Smith DJ, Self HR. 1955. Observations on the survival of Leptospira australis A in soil and water. J. Hyg. (Lond.) 53:436–444 - PMC - PubMed
    1. Trueba G, Zapata S, Madrid K, Cullen P, Haake D. 2004. Cell aggregation: a mechanism of pathogenic Leptospira to survive in fresh water. Int. Microbiol. 7:35–40 - PubMed
    1. Adler B, de la Peña Moctezuma A. 2010. Leptospira and leptospirosis. Vet. Microbiol. 140:287–296 - PubMed
    1. Chakraborty A, Miyahara S, Villanueva SY, Saito M, Gloriani NG, Yoshida S. 2011. A novel combination of selective agents for isolation of Leptospira species. Microbiol. Immunol. 55:494–501 - PubMed
    1. Inada R, Ido Y, Hoki R, Kaneko R, Ito H. 1916. The etiology, mode of infection, and specific therapy of Weil's disease (spirochaetosis icterohaemorrhagica). J. Exp. Med. 23:377–402 - PMC - PubMed

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