Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Microbiology

This study was carried out on 250 chickens head were collected from broilers farms in Egypt, the samples were examined on different microbiological media in which, the result revealed that the major pathogens associated with swollen head syndrome in broilers wereE.coli , K. pneumoniae , P. aeruginosa, S.aureus, S.xylous, S.intermedius, E.faecalis ,S.epidermidius, and E.faeciumin percentage of 28% (70\250), 2.8% (7\250), 2.4% (6\250), 1.6% (4\250), 1.2% (3\250), 1.2% (3\250), 0.8% (2\250), 0.8% (2\250) respectively. Serotyping of recovered E.coli revealed that the main serotypes recovered from swollen head syndrome wereO78:K80 followed by O8: K60 in percentage 20% (14\70) and 17.2%. (12\70) respectively . Antibiogram for the recovered pathogens showed that low incidence of antibiotic resistance among recovered Staphylococcus and Streptococcus spp. while E.coli isolates showed 43%(30\70) and 29%(20\70) resistance to Colistin and Erythromycin respectively ,in another hand K.pneumoniae isolates were resistant to tetracycline and Ciprofloxacin, Cefotaxime ,Neomycin, Erythromycin ,Sulfa-trimethoprime in percentage of 57% (4\7) and 43 (3\7)% respectively and also P. aeruginosa were 80%(4\6) and 60 (3\6)% resist to Cefotaxime and Colistin, Tertacycline respectively. Randam 3 P.aeruoginosa isolates were found to be positive for phzM gene at bp 875

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