Amir Cheraghi - Islamic Azad University, Farahan Branch, Farahan, Iran.
Shahla Mohammad Ganji - National Institute Genetic Engineering and Biotechnology, Tehran, Iran.
Bita Najmi - Islamic Azad University, Qom Branch, Qom, Iran.

Background and Aims: Recently it has been proved that some of Enterobacteriacea like Klebsiella pneumoniae, which carry PKS islands, damage dsDNA by encoding Colibactin genotoxin; and finally they induce some apoptosis in damaged mucosal cells. This study aimed to isolating the clbN and clbB genes, which are the markers of the PKS genomic island, from PKS cluster in these bacteria Materials and Methods: In this study, ۱۱۰ biopsies were obtained from colorectal cancer patients referred to the clinic of Imam Khomeini Hospital. Then, all samples were cultured in LB medium for bacterial isolation. In the next step, Klebsiella peunomoniae was detected by biochemical and microbiological tests. Finally, the genomes were extracted by boiling method and then were amplified by PCR with specific clbN and clbB gene primers. Results: Our findings have showed ۳۰ Klebsiella pneumonia isolated out of ۱۱۰ biopsies (۲۷.۳%) from patients with colorectal cancer; in which all of biochemical and microbial experiments including Gram-negative staining confirmed this bacteria. Also, ۲۳.۲۳% frequency of clbN were positive, ۲۰% frequency of clbB were positive genes in the isolated Klebsiella pneumonia, and ۱۳.۳۳% frequency were positive for both clbB and clbN genes as simultaneous. Conclusions: It is expected to find a significant correlation between Klebsiella bacteria which carries PKS genes and colorectal cancer by increased number of samples. The lower frequencies for Klebsiella with clbB and clbN positive strain in patients with colorectal cancer were shown in European countries based on the results of this study rather than the similar studies.

clbB, clbN, Colorectal cancer, Klebsiella pneumoniae, PCR