Identification of species and sources of Cryptosporidium oocysts in storm waters with a small-subunit rRNA-based diagnostic and genotyping tool - PubMed (original) (raw)

Identification of species and sources of Cryptosporidium oocysts in storm waters with a small-subunit rRNA-based diagnostic and genotyping tool

L Xiao et al. Appl Environ Microbiol. 2000 Dec.

Abstract

The identification of Cryptosporidium oocysts in environmental samples is largely made by the use of an immunofluorescent assay. In this study, we have used a small-subunit rRNA-based PCR-restriction fragment length polymorphism technique to identify species and sources of Cryptosporidium oocysts present in 29 storm water samples collected from a stream in New York. A total of 12 genotypes were found in 27 positive samples; for 4 the species and probable origins were identified by sequence analysis, whereas the rest represent new genotypes from wildlife. Thus, this technique provides an alternative method for the detection and differentiation of Cryptosporidium parasites in environmental samples.

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Figures

FIG. 1

FIG. 1

Differentiation of the Cryptosporidium parasites in storm water samples by SSU rRNA-based PCR-RFLP. Lanes 1, 2, 4, 8, 10, and 11, unknown Cryptosporidium spp.; lane 3, Cryptosporidium from snakes; lane 5, C. baileyi; lane 6, Cryptosporidium opossum genotype 2; lanes 7 and 9, C. parvum bovine-like genotype.

FIG. 2

FIG. 2

Nucleotide sequence diversity among Cryptosporidium water genotypes in one of the polymorphic regions of the SSU rRNA gene. Dots denote nucleotides identical to those from the C. parvum bovine (Bov) genotype sequence, and dashes indicate deletions. Hum, C. parvum human genotype.

FIG. 3

FIG. 3

Phylogenetic relationship among various Cryptosporidium water genotypes as inferred by neighbor-joining analysis. Bootstrap values above 50% from 1,000 pseudoreplicates are shown on the branches.

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