الفهرس 
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Abstract
This study determined the prevalence of C.botulinumand C.perfringens in consumable fish. A total number of 200 random fish samples (100 salted sardine, 25 faseikh, 25 smoked fish, 20 canned tuna , 20 canned salmon and 10 canned mackerel) were collected from different localities and from different hygienic levels at Dakahlia Governorate markets, Egypt. Samples were examined bacteriologically for C. botulinumand C. perfringens. Mouse bioassay method was done for detection of C. botulinumtoxins. PCR was done for detection of C. perfringens alpha toxin gene. Two C.botulinumisolates were recovered from 100 examined salted sardine samples with a percentage of 2%. NoC. botulinum isolates were recovered from examined faseikh,smoked fish,canned tuna, canned salmon and canned mackerel samples. The total number of positive samples forC. perfringens was 85 (42.5%) including 63(63%) from saltedsardine, 12(48%) from faseikhand 10 (40%) from smoked fish. No C. perfringensisolates were recovered from examined canned tuna,canned salmon and canned mackerel samples. Nagler’stestwas applied on the recovered C.perfringens isolates. Typing ofC.perfringens isolates revealed that the incidence of toxigenic and non-toxigenic isolates were 76.5% and 23.5% respectively. Typing of toxigenic strains of C. perfringensrevealed that C. perfringens type A was the most predominant one comparing with type D with a percentage of 64.7%and11.8%respectively.C.perfringensisolates were examined for their susceptibility to antimicrobial agents. Results showed that the most effective drugs were Penicillin G, Tetracycline, Chloramphenicol and Ciprofloxacin, while the less effective ones were Gentamicin followed by Erythromycin.
PCR was successful in the detection of C. perfringens alpha toxin gene in randomly examined five C.perfringens isolates at 402 bpamplicon.