5087
Mohamed Ali Ibrahim Osman
Biodiversity and surveillance of free-living amoebae in drinking water distribution systems
free-living amoebae, Biofilm , pipe lines
Examination of 144 tap water samples collected from different drinking water pipe lines revealed the presence of free-living amoebae (FLAs) in 42.4% of them. The highest occurrence (52.8%) of free living amoebae was recorded in summer season. The rate of detection of free-living amoebae decreased gradually to be 47.2, 41.7 and lastly 27.8% in autumn, spring and winter, respectively. The highest percentage of FLAs were recorded in summer in both cast iron and stainless steel pipes (75 and 58.3%, respectively). The occurrence of FLAs in water samples passing through PVC pipes was the same in spring, summer and autumn (represented by 25.0% for each), while it reached the lowest occurrence (16.7%) in winter. Free-living amoebae were detected in biofilm obtained from cast iron and stainless steel pipe lines, but not from PVC pipes. The presence of FLAs in tap water appeared to be conventionally related to turbidity obtained from biofilm inside different examined pipe material. Four genera of FLAs (Acanthamoeba, Naegleria, Vannella and Hartmannella) were isolated from tap water samples. Eight different species of Acanthamoeba were isolated from tap water and morphologically identified as A. triangularis, A. echinulata, A. astronyxis, A. comandoni, A. griffini, A. culbertsoni, A. quina and A. lenticulata. Members of genera Acanthamoeba and Vannella were also isolated from biofilm encountered inside cast iron pipes. The morphologically identified FLAs were subjected to molecular confirmation by simple PCR techniques using genus specific primers for Acanthamoeba, Naegleria, Hartmannella and Vannella. All the morphologically identified Acanthamoeba species (that were similar to and suspected to be Balamuthia) gave negative results when tested with PCR using species specific primers for Balamuthia mandrillaris.
2016
M.Sc
Benha
Science