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Cryptosporidium propidium monoazide-PCR, a molecular biology-based technique for genotyping of viable Cryptosporidium oocysts.

Authors :
Brescia CC
Griffin SM
Ware MW
Varughese EA
Egorov AI
Villegas EN
Source :
Applied and environmental microbiology [Appl Environ Microbiol] 2009 Nov; Vol. 75 (21), pp. 6856-63. Date of Electronic Publication: 2009 Sep 11.
Publication Year :
2009

Abstract

Cryptosporidium is an important waterborne protozoan parasite that can cause severe diarrhea and death in the immunocompromised. The current methods used to monitor for Cryptosporidium oocysts in water are the microscopy-based USEPA methods 1622 and 1623. These methods assess total levels of oocysts in source waters, but do not determine oocyst viability or genotype. Recently, propidium monoazide (PMA) has been used in conjunction with molecular diagnostic tools to identify species and assess the viability of bacteria. The goal of this study was the development of a Cryptosporidium PMA-PCR (CryptoPMA-PCR) assay that includes PMA treatment prior to PCR analysis in order to prevent the amplification of DNA from dead oocysts. The results demonstrated that PMA penetrates only dead oocysts and blocks amplification of their DNA. The CryptoPMA-PCR assay can also specifically detect live oocysts within a mixed population of live and dead oocysts. More importantly, live oocysts, not dead oocysts, were detected in raw waste or surface water samples spiked with Cryptosporidium oocysts. This proof-of-concept study is the first to demonstrate the use of PMA for pre-PCR treatment of Cryptosporidium oocysts. The CryptoPMA-PCR assay is an attractive approach to specifically detect and genotype viable Cryptosporidium oocysts in the water, which is critical for human health risk assessment.

Details

Language :
English
ISSN :
1098-5336
Volume :
75
Issue :
21
Database :
MEDLINE
Journal :
Applied and environmental microbiology
Publication Type :
Academic Journal
Accession number :
19749067
Full Text :
https://doi.org/10.1128/AEM.00540-09