Recent studies have shown that Cryptosporidium can be found in finished reclaimed
water at levels higher than previously reported, which was prior to implementation of a revised
method for detecting the pathogens. In addition, recent work shows that infectious
Cryptosporidium was detected in finished reclaimed water using a tissue culture assay to assess
potential human infectivity (Quintero-Betancourt, et al., 2003).
The current detection method (USEPA Method 1623) allows for the direct enumeration
of Cryptosporidium; however, it cannot assess the potential viability or ability of these organisms
to infect humans. The polymerase chain reaction (PCR) is a novel method suggested for
identifying Cryptosporidium in water samples processed by Method 1623 (Xiao, et al., 2000).
PCR detects the DNA of the pathogen and can be species and genotype specific. Thus, the
purpose of this study was to: evaluate and compare the use of Method 1623 alone or combined
with PCR for detecting Cryptosporidium in reclaimed water; determine the levels of
Cryptosporidium in finished water in reclaimed water in central Florida; and, ascertain whether
the organisms detected were viable and potentially infectious to humans.
USEPA Method 1623 was performed by concentrating 20 to 50 L of water onto an
Envirochek HV filter (Pall Gelman, Ann Arbor, MI). Target organisms were eluted off the filter,
concentrated by centrifugation, and isolated using immunomagnetic separation (IMS) followed
by an immunofluorescence staining procedure (IFA) for identification (USEPA Method 1623,
2001). Isolation and preparation of Cryptosporidium DNA for PCR was performed using
DNazol Reagent (Invitrogen, Carlsbad, CA). Primers specific for a small subunit rRNA fragment
common to all Cryptosporidium species (Xiao, et al., 2000) were used to amplify the DNA. Includes 4 references, tables.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 250 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 4 |
| Published : | 06/17/2004 |
