Distribution of sul1 gene to sulfonamide resistance in Escherichia coli isolated from Zarjob River(Iran) in Guilan province

Importance of Zarjob River in Guilan province is because of its large area. On the other hand, the industrial, urban and agriculture wastewater of Rasht caused severe pollution of the river and make it the most polluted river in the province.E.coli is the main indicator of water fecal contamination. So studying Zarjob River and antibiotic resistance of E.coli is important because it could indicate the pollution of the river, threatening the health of people around the river and the pollution of Caspian Sea. During 5 months (September to December), 25 samples from 5 stations in Zarjob river, were collected. At the first, the MPN test was done, then the samples that were positive, were cultured in EMB and incubated for 24 hours..Antibiogram test was done according to disk diffusion method and CLSI (in Muller Hinton Agar).The serotyping, with multi antiserum kit of pathogenic E.coli was done.For extracting DNA, extraction kit, and for displaying sul1 gene in E.coli, PCR test were used. Finally it was found that 20% of samples were resistance to sulfamethoxazole and all of them were belong to Group III (O128, O125, O44) and according to PCR all of them had sul1 gene. Antibiotic resistance has become a global issue. The most polluted river in the province of Giulan is Zarjob, which can cause pollution of various types of waters, aquatic organisms, fish and other marine organisms used by humans