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Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

Naganandhini S, Kennedy ZJ, Uyttendaele M, Balachandar D - PLoS ONE (2015)

Bottom Line: The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days) than those compared (60 days).In cocopeat, O157 recorded significantly longer survival than other two strains.The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA).

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641003, India.

ABSTRACT
The persistence of Shiga-like toxin producing E. coli (STEC) strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU) was compared with non-pathogenic (MTCC433) and genetically modified (DH5α) strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days) than those compared (60 days). Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA). The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

No MeSH data available.


Related in: MedlinePlus

Wild (A) and EGFP tagged (B) E. coli strains used in the present study.The pGreenTIR conferring ampicillin resistance and enhanced green fluorescence under UV was transformed to all the three strains, viz., DH5α, MTCC433 and O157-TNAU.
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pone.0130038.g001: Wild (A) and EGFP tagged (B) E. coli strains used in the present study.The pGreenTIR conferring ampicillin resistance and enhanced green fluorescence under UV was transformed to all the three strains, viz., DH5α, MTCC433 and O157-TNAU.

Mentions: For easy detection in soil under controlled condition, all the three strains were introduced with plasmid pGreenTIR [35], a derivate of pUC18 in which mutated gfp gene (containing a double F65L S65T amino acid change that increases green fluorescent protein (GFP) stability and fluorescence) and ampicillin resistance gene are expressed. This plasmid also contains an improved translation initiation region for prokaryotes, including the translational enhancer and the Shine–Dalgarno regions of phage T7 gene 10, so that synthesis of GFP is enhanced. All the three E. coli strains grown in Luria Birtani (LB) medium (HiMedia, India) were transformed with pGreenTIR plasmid by following standard CaCl2-method with selection for ampicillin resistance (100 μg/ml) and GFP production under UV light (Fig 1). Virulence profiles (stx1 and stx2 genes) of the three strains with and without pGreenTIR were characterized by PCR as primers and conditions described by Cebula et al. [36]. Additionally, the uidA gene, responsible for β glucuronidase activity specific to E. coli was also confirmed by PCR [36]. Further, genome fingerprints of each strain with and without plasmid were characterized by BOX-A1R-based repetitive extragenic palindromic-PCR (BOX-PCR) using BOX-A1R primer [37] as previously reported by Urzì et al. [38].


Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

Naganandhini S, Kennedy ZJ, Uyttendaele M, Balachandar D - PLoS ONE (2015)

Wild (A) and EGFP tagged (B) E. coli strains used in the present study.The pGreenTIR conferring ampicillin resistance and enhanced green fluorescence under UV was transformed to all the three strains, viz., DH5α, MTCC433 and O157-TNAU.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477969&req=5

pone.0130038.g001: Wild (A) and EGFP tagged (B) E. coli strains used in the present study.The pGreenTIR conferring ampicillin resistance and enhanced green fluorescence under UV was transformed to all the three strains, viz., DH5α, MTCC433 and O157-TNAU.
Mentions: For easy detection in soil under controlled condition, all the three strains were introduced with plasmid pGreenTIR [35], a derivate of pUC18 in which mutated gfp gene (containing a double F65L S65T amino acid change that increases green fluorescent protein (GFP) stability and fluorescence) and ampicillin resistance gene are expressed. This plasmid also contains an improved translation initiation region for prokaryotes, including the translational enhancer and the Shine–Dalgarno regions of phage T7 gene 10, so that synthesis of GFP is enhanced. All the three E. coli strains grown in Luria Birtani (LB) medium (HiMedia, India) were transformed with pGreenTIR plasmid by following standard CaCl2-method with selection for ampicillin resistance (100 μg/ml) and GFP production under UV light (Fig 1). Virulence profiles (stx1 and stx2 genes) of the three strains with and without pGreenTIR were characterized by PCR as primers and conditions described by Cebula et al. [36]. Additionally, the uidA gene, responsible for β glucuronidase activity specific to E. coli was also confirmed by PCR [36]. Further, genome fingerprints of each strain with and without plasmid were characterized by BOX-A1R-based repetitive extragenic palindromic-PCR (BOX-PCR) using BOX-A1R primer [37] as previously reported by Urzì et al. [38].

Bottom Line: The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days) than those compared (60 days).In cocopeat, O157 recorded significantly longer survival than other two strains.The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA).

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641003, India.

ABSTRACT
The persistence of Shiga-like toxin producing E. coli (STEC) strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU) was compared with non-pathogenic (MTCC433) and genetically modified (DH5α) strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days) than those compared (60 days). Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA). The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

No MeSH data available.


Related in: MedlinePlus