The current study aimed to investigate the prevalence of Escherichia coli (E. coli ) and Salmonellae infections in broiler chickens detecting the genotypic characters of multidrug resistant (MDR) isolates and determining the cinnamon and oreganium oils activities against these isolates. Two hundred samples were collected from 120 diseased broiler chickens of
different ages (1-5weeks) from different farms in Beni-Suef and El-Fayoum Governorates during the period from January 2015 up to September 2015. Bacteriological examination showed that 115 bacterial isolates were recovered with a prevalence rate of 57.5% of which 91 E. coli isolates (45.5%) and 24 Salmonella isolates (12%). Serogrouping of E. coli isolates revealed that serogroup O78 was the most prevalent (27.5%) followed by serogroups O158 (18.7%) and O128 (16.5%). Serotyping of Salmonella isolates showed that S. Kentuky, S. Enteritidis and S. Infantis were identified at rates of 37.5%, 33.3% and 29.2%, respectively. Results of antiprogram showed that 73 E. coli isolates (80.2%) and 18 Salmonella isolates (75%) were MDR. PCR was applied on 8 MDR isolates to determine the 7 genes. BlaTEM gene was the most prevalent found in all E. coli isolates (100%) followed by sul1 (92.9%), iutA (78.6%) and iss (71.4%) while that invA gene was the most prevalent in all Salmonella serovars (100%) followed by sul1 (75%) and tetA (62.5%). The antibacterial activities of
cinnamon and oreganium oils were tested against 50 MDR; 32 E. coli and 18 Salmonella isolates. Oreganium completely inhibited the growth of all the tested bacterial isolates at a concentration of 1% and at 0.5%, concentration inhibited also all E. coli isolates and 83.3% Salmonellae isolates. Cinnamon oil completely inhibited the growth of all the tested bacterial
isolates at a concentration of 3% while at 2% concentration 59.4% of E. coli isolates and 33.3% of Salmonellae isolates were inhibited