Genetic characterization of Cryptosporidium strains from 218 patients with diarrhea diagnosed as having sporadic cryptosporidiosis - PubMed (original) (raw)

Genetic characterization of Cryptosporidium strains from 218 patients with diarrhea diagnosed as having sporadic cryptosporidiosis

J McLauchlin et al. J Clin Microbiol. 1999 Oct.

Abstract

Samples of whole feces in which Cryptosporidium oocysts were recognized by hospital laboratories were collected from 218 patients with diarrhea. All samples were reexamined by light microscopy, and oocysts were detected in 211 samples. A simple and rapid procedure for the extraction of DNA from whole feces was developed, and this was used to amplify fragments of the Cryptosporidium outer wall protein (COWP), the thrombospondin-related adhesive protein C1 (TRAP-C1), and the 18S rRNA genes by PCR. For seven samples oocysts were not detected by microscopy and DNA failed to be amplified by the three PCR procedures. Among the 211 samples "positive" by microscopy, the sensitivities of PCRs for the 18S rRNA, COWP, and TRAP-C1 gene fragments were 97, 91, and 66%, respectively. The sensitivities of all three PCR procedures increased with increasing numbers of oocysts as observed by microscopy. Two genotypes of the COWP and TRAP-C1 genes can be detected by PCR-restriction fragment length polymorphism analysis. With this series of samples, the same genotypes of the COWP and TRAP-C1 genes always segregated together. A combined genotyping data set was produced for isolates from 194 samples: 74 (38%) were genotype 1 and 120 (62%) were genotype 2. Genotype 2 was detected in a significantly greater proportion of the samples with small numbers of oocysts, and genotype 1 was detected in a significantly greater proportion of the samples with larger numbers of oocysts. There were no significant differences in the distribution of the genotypes by patient sex and age. The distribution of the genotypes was significantly different both in patients with a history of foreign travel and in those from different regions in England.

PubMed Disclaimer

Figures

FIG. 1

FIG. 1

Distribution of both C. parvum genotypes from 159 patients with cryptosporidiosis during the second half of 1998 by regional health authorities in England. Patients with a recent history of foreign travel have been excluded. For each region, the name of the regional health authority is given above the number of patients infected with genotype 1: number of patients infected with genotype 2.

References

    1. Arrowood M J. Diagnosis. In: Fayer R, editor. Cryptosporidium and cryptosporidiosis. Boca Raton, Fla: CRC Press, Inc.; 1997. pp. 43–64.
    1. Awad-El-Kariem F M, Robinson H A, Dyson D A, Evans D, Wright S, Fox M T, McDonald V. Differentiation between human and animal strains of Cryptosporidium parvum using isoenzyme typing. Parasitology. 1995;110:129–132. - PubMed
    1. Awad-El-Kariem F M, Robinson H A, Petry F, McDonald V, Evans D, Casemore D. Differentiation between human and animal isolates of Cryptosporidium parvum using molecular and biological markers. Parasitol Res. 1998;84:297–301. - PubMed
    1. Bonnin A, Fourmaux M N, Dubremetz J F, et al. Genotyping human and bovine isolates of Cryptosporidium parvum by polymerase chain reaction-restriction fragment length polymorphism analysis of a repetitive DNA sequence. FEMS Microbiol Lett. 1996;137:207–211. - PubMed
    1. Boom R, Sol C J A, Salimans M M M, Jansen C L, Wertheim van Dillen P M E, van der Noordaa J. Rapid and simple method for purification of nucleic acids. J Clin Microbiol. 1990;28:495–503. - PMC - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources