This study was carried out on five poultry farms at Ismailia Governorate suffering from respiratory symptoms accompanied with gastroenteric findings. Post mortem findings revealed septicemia. Bacteriological examination revealed the isolation of E. coli (60 %& 40%) while ORT was (26.6% & 20%) and E. coli concomitant with ORT were (18.6% & 12%) in broilers and layer respectively. The eighty-five E. coli isolates were as follow: seventy were identified to six different serotypes, O78, O26, O1, O2, O157 and O111, with different frequencies and fifteen untypable. All E. coli isolates tested for evaluation of it's virulence by Congo red binding assay, Hemolytic activity, Invasiveness assay and Enterotoxins assays. The in vitro Antimicrobial resistance patterns of the isolates were reported. Experimental infections of O. rhinotracheale  were examined and scored weekly. Recovery from respiratory disease was overall most successful after Enrofloxacin treatment. It could be concluded that air sacculitis is prevalent among broiler and layers chickens at Ismailia province. E. coli is the most commonly incriminated agent and Ornithobacterium rhinotracheale stands as the second most important pathogen. Therefore, management and sanitation practices designed to reduce the number of these types of organisms in the birds' environment are necessary.