The microbial community in oral cavity associated with oral infection and disease, variety of microbes have been recorded in oral cavity with different genetic properties, the present study aims to study some oral cavity isolates using classical methods and PCR for molecular detection O-antigen genes, results show that there were four isolates, three were G- E. coli ; Klebsilla pneumonia and Cardiobacterium hominis while the fourth species was Staphylococcus aureaus , it had different response to antibiotics E. coli and Klebsilla pneumonia were more resistance. The plasmid profile didn’t show any plasmids as well as O- antigen genes it was negative for all isolates. The present study concluded that oral cavity have variety species with different genomic properties , it need more investigation about other genes and bioactivity.