Antibiotic resistance pattern and frequency of biofilm producing genes in Escherichia coli isolates from nosocomial infections in Tehran in 2023

Biofilm is a community of bacteria surrounded by extracellular polymeric substances, providing protection against harsh environmental conditions and serving as a major cause of various infections. The objective of this study was to evaluate the effects of various antibiotics on Escherichia coli biofilms obtained from nosocomial infections, as well as to explore the correlation between virulence factors and the formation of biofilms.A total of 140 Escherichia coli isolates from nosocomial infections were analyzed for antibiotic susceptibility using the Kirby-Bauer method. Biofilm formation was assessed using the crystal violet microplate technique, with a focus on identifying biofilm-associated genes such as afa, pap, sfa, agg, and fimH. Based on CLSI criteria, Imipenem exhibited the highest sensitivity at 99.28%, whereas Cotrimoxazole showed the highest resistance at 91.43%. Among the isolates, 41.43% did not form biofilms, while 21.43%, 19.29%, and 17.85% formed weak, moderate, and strong biofilms, respectively. A correlation was found between biofilm formation and antibiotic resistance. The frequency of fimH, Pap, Sfa, afa, and agg genes among the isolates was 59.28%, 26.42%, 17.85%, 8.57%, and 0.00%, respectively. The study suggests that high antibiotic resistance may be associated with strong or moderate biofilm production. The ability of E. coli strains to form biofilms may play a crucial role in managing nosocomial infections.

Antibiotic resistance pattern and frequency of biofilm producing genes in Escherichia coli isolates from nosocomial infections in Tehran in 2023 Keywords:

Escherichia coli , biofilm producing genes , Antibiotic resistance