Description
This powerpoint presentation begins by providing a brief overview of nematodes and protection mechanisms of microorganisms in ultraviolet (UV) disinfection. Research objectives included the following: assess the significance of nematodes interms of protecting waterbornepathogens against UV disinfection usingE. coli OP50 – GFP as a surrogate forenteropathogenic bacteria, and B. subtilis spores as a possible surrogatefor Cryptosporidium. Study designincluded the following: synchronized nematodes (adults); bacterial strains ofE. coli OP50 – GFP andB. subtilis spores ATCC 6633;Chlorination – 10 ppm * 5 min for E. coli, and15 ppm * 20 min for B. subtilis spores; Sonication: 15 W * 60 sec in 5 ml;UV exposure – collimated beam apparatus, LP, 254 nm, 2 UV fluences: 5 – 40 mJ/cm<sup>2</sup>;culture medium for bacterial counts – m-Endo for E. coli, andTSB for B. subtilis spores. Presentation conclusions indicate the following:internalization by nematode C. elegans offers significantprotection to bacteria (E. coli, B. subtilis spores) against UVdisinfection at typical fluence applied in WTP (40 mJ/cm<sup>2</sup>); thus, the authors suppose that pathogenic microorganisms indrinking water could survive UV disinfection treatment whenprotected inside nematodes;this should be taken into account when assessing themicrobial risk associated to drinking water; however, the low concentration of pathogenicmicroorganisms in most drinking water sources suggeststhat pathogen ingestion by higher organisms in naturalconditions remains a low probability event; and,while higher organisms are known to be ubiquitous indrinking water systems, studies are lacking in terms ofquantification of internalized pathogen occurrence in fieldconditions. Includes 2 references, table, figures.
Product Details
- Edition:
- Vol. – No.
- Published:
- 11/01/2008
- Number of Pages:
- 26
- File Size:
- 1 file , 1.5 MB
- Note:
- This product is unavailable in Ukraine, Russia, Belarus
