اسم المؤلف:
مصطفى عدنان عیدان
اسم المشرف:
قيثار رشيد مجيد | صباح مالك حبيب الشطي
المستخلص:
It was obtained 55 local isolates of Clostridium perfringens out of153 samples taken from different food sources included (meat , chicken ,fish and shrimp and miscellaneous foods).All of the samples were taken from six locally markets in Basrahcity included (Old Basrah , Al - Ashaar market , Al - Assmai market ,Fivemiles market ,Karmat Ali market and Al - Hartha market). Isolation , identification and the studying characteristics tested were carried out after on growing on TSC Agar . All isolates were selected and subjected for studying cultural and morphological in addition to biochemical test were done . All isolates were gave black colonies on the TSC Agar , from all these tests , its indicate that the isolate were belong to Clostridium perfringens. Microscopic examination showed that bacteria were bacilli shape , Gram positive , obligately anaerobic , capsule forming , spores forming , moreover the shapes of spores was oval (subterminal ) internal spores and non - motile .Bacteria were grown on Blood agar medium (5% Sheep blood) , Egg yolk medium , Crossley milk medium , and Reinforced clostridial broth , the results appeared double zone of haemolysis , produced Lecithinase enzyme with clear zone hydrolysis , Clear stormyfermentation , produce hydrogen sulphite (H2S) with black colour for Blood agar , Egg yolk agar , Crossley milk medium and Reinforced clostridial broth , respectively . The isolates bacteria had the ability to reduce nitrate to nitrite , in addition to gelatin liquefaction (liquefaction gelatin after 48 hours) . The isolates bacteria were negative for catalase , oxidase , starch hydrolysis , lipolytic , negative for indole , positive for methyl red , ferment glucose , sucrose , lactose , maltose , galactose and trehalose , however it was non ferment xylose , melibiose , arabinose , salicin, mannitol, and raffinose . Tolerance tests were applied to study the some environmental conditions such as pH (3 - 10) , temperature (8 - 55) C° and NaCl % (0 - 10). Results showed that optimum conditions were (6 - 7) , (37 - 40)C° and (0 - 1) for pH , temperature and NaCl , respectively . The frequently prevalence of these were 48 , 46 , 24 , 23 and 10% for chicken meat , red meat , fish and shrimp , dairy products and miscellaneous foods , respectively . While to the local markets the frequently prevalence were 46 , 44 , 37 , 30 , 32 , 24 % for Karmat Ali , Old Basrah , Hartha , , Five miles ,AL - Ashaar and Al - Assmai , respectively .On the other hand , in this study and the first time new selective medium prepared instead of TSC Agar which used Neomycin antibiotic instead of Cycloserine . The new medium showed good results compared with TSC Agar because it was cheap , efficient , precise in isolation and identification tests and shortly of the isolation time .Susceptibility antibiotics tests toward 30 antibiotics was assayed.The isolates of Closridium perfringens were resistance (100%) for 3 antibiotics Neomycin , Gentamycin , Streptomycin and susceptibility (100%) for 7 antibiotics Cloxacillin , Chloramphenicol , Amoxicillin , Nitrofurontion , Nalidxic acid , Cefotaxime and Vancomycin .The PCR Technique was used to detect the toxins genes that are responsible for food poisoning . The DNA was isolated and identified by using 16S rDNA and cpα toxins .The results showed that the selected isolated contained α toxin thus confirmed this bacteria Clostridium perfringens certainly . The PCR results showed that there were three types in tested isolates . Type A (71.43%) which contain α toxin ,this was responsible of food poisoning . Type B (7.14%) which contain α , β and ε toxins . Type C (21.43%) which contain α and β toxins , however the results of PCR did not show any type for both D (which contain α , ε toxins ) and E (which contain α , i toxins) .
