Introduction: Some pathogenic strains of Escherichia coli can cause intestinal and external intestinal diseases. Enteropathogenic Escherichia coli is one of the most important factors of children diarrhea in developing countries. The aim of this study was to determine the prevalence of antibiotic resistance and the prevalence of  tetracycline resistance genes in Escherichia coli causing diarrhea.

Materials & methods: A total of 150 stool samples of diarrheal children under 5 years from treatment centers in Tehran hospital were selected randomly, collected and finally 55 cases were confirmed as Escherichia coli with different biological and biochemical tests. Antibiogram testing was performed by disk diffusion method according to CLSI guidelines with various antibiotics. Multiplex PCR test was used for identifying the tetracycline resistance genes.

Findings: The results showed that  the most resistance to antibiotics were amoxicillin and tetracycline 36.3% and 27.5%, respectively, and were reported the minimum inhibitory concentration (MIC) of the strains resistant to tetracycline, 66.6% of the strains 128 μg/ ml and 33.3 % of the strains 256 μg/ ml. The most prevalence were identified of tetracycline resistant genes, genes tetBand tetA in 6 samples (20%). TetC gene identified in 2 isolated and tetD gene in 1 isolation.

Discussion & Conclusions: Antibiotic-resistant Escherichia coli in children with diarrhea can indicate excessive use of antibiotics, the spread of antibiotic resistance gene cassettes and genetic transmission among the population. Treatment and absence of resistance gene in pathogenic strains, is necessary determine the resistance pattern and the MIC to follow up the process of resistance.