5076
Yasmin Yousif Mohamed
Importance of Lisfurta monocytogenes as Food-borne Infection Transmissible to Man Through Food
L. monocytogenes' meat' milk' culture' PCR' phylo genetic analYsis
Listeria monocytogenes is considered one of the most important food-borne pathogens that is transmitted to human mainly via contaminatedfood. In an attempt to throw more light on zoonotic importance of L. monocytogenes as food-bome pathogen' a total of 340sampleswereusedforthisstudy;thesesamplesincluded250 food samples (50 beef burger, 50 sausages' 25 Luncheon' 25 minced meat,50rawmilkand50karieshcheese)wererandomlycollected from retail markets, groceries and restaurants in different localities in El Giza Governorate. In addition swabs were taken from 40 food refrigerators and stool samples from 50 diarrheic children' All samples were cultured for the isolation of I. monocytogeres using the conventional Intmatioilt Organization for standardization (ISO,11290-1)method.Theisolatesweretestedbiochemicallyusing Listeria Microbact lZL andconfirmed by PCR' The results revealed that the isolation rates of L' monocytogenes were 8 oh' 4o/o' 4o/o for beef burger, minced meat and Luncheon respectively' while sausage samples were totally negative' I' ivanovii and L' seeligeri were recoveredinapercentageof2o/oforeachinbothsausageandbeef burger samples. Moreover, 8% of raw milk samples were positive for L. monocytogenes,whereas kariesh cheese samples and refrigerator swabs were negative' Moreovet Listeria grayi was isolated from human stool (2.5%) rising the question about the opportunistic nature of such nonpathogenic bacteria' DNA sequencing of hlyA gene for PCRproductsoftheobtainedmeatproductsisolatesandthededucedphllogenetic analysis revealed that the isolates were L' monocytogenes w\thhomology results (gS-gg%)' The next generation sequencing helpful in rapid acquisition of sequence data to facilitate detection and characterization of pathogenic strains of L' monocytogenes. Ln conclusion' the high isolation rates of I' monocytogenesafio\gtheexaminedfoodstuffshighlightedthe crucialroleoffoodtobeanimportantvehicleforsuchpathogen'
2015
M.Sc
Cairo
Veterinary Medicine