International Travel Medicine Center of Iran International Journal of Travel Medicine and Global Health 2322-1100 13 3 2025 09 01 Detection of aggR and agg4A Genes and Antibiotic Resistance Profiles in Biofilm-Forming Escherichia coli Clinical Isolates from Miandoab Hospitals 135 141 220895 10.30491/ijtmgh.2025.519504.1474 EN Marjan Bagheri Department of Microbiology, Bon.C., Islamic Azad University, Bonab, Iran. Zahra Hojjati Bonab Department of Microbiology, Bonab Branch, Islamic Azad University, Bonab, Iran. Hossein Soltanzadeh Islamic Azad University, Bonab, East azarbayjan, Iran Journal Article 2025 04 26 Background: Escherichia coli (E.coli)is a non-pathogenic facultative bacterium that is the predominant pathogen in the human intestine, however, some of its strains are known to be the cause of many human infections. The major adhesins of enteroaggregative strains has aggR gene encodes AAF-I. This strain has too agg4A encodes AAF-IV, each of which has a specific role. Various factors, such as the high volume of antibiotic use, poor hygiene conditions contribute to the development and spread of antibiotic resistance.<br />Material and Methods:Urine samples were taken from 100 patients referred to Miandoab Hospital in Iran and cultured in Eosin methylene blue(EMB) selective culture medium. E. coli differential test was performed for positive samples. Antibiogram test was used to investigate antibiotic resistance. PCR was performed for investigation the presence of aggR and agg4A genes<br />Results: In this study, 80% of the samples were resistant to the antibiotic ampicillin and 20% were sensitive to the antibiotic ampicillin. In this study, 20% of the samples formed weak biofilm, 20% of the samples formed medium biofilm, 50% of the samples formed strong biofilm, and 10% of the samples formed very strong biofilm. One sample (5%) had the aggR gene and six samples (30%) had the agg4A gene.<br />Conclusion: According to the results of this study, aggR and agg4A, as genes effective in biofilm biosynthesis, have different effects on biofilm formation of clinical isolates of E.coli by PCR method, and these effects are exerted through the influence on the expression of genes involved in biofilm formation. https://www.ijtmgh.com/article_220895_6fa95572642b30061d766428a6cf581e.pdf