Antibiotic resistance and biofilm formation in children with Enteropathogenic Escherichia coli (EPEC) in Brazilian Amazon.

Introduction: Enteropathogenic Escherichia coli is an important causative agent of diarrhea in both developed and developing countries.

Methodology: We assessed the antibiotic resistance profile and the ability of 71 Enteropathogenic Escherichia coli (EPEC) isolates from children in the age group 6 years, or younger, to form biofilm. These children were hospitalized in Cosme and Damião Children Hospital in Porto Velho, Western Brazilian Amazon, between 2010 and 2012, with clinical symptoms of acute gastroenteritis.

Results: The highest frequency of atypical EPEC (aEPEC) isolates reached 83.1% (59/71). Most EPEC isolates presented Localized Adherence Like (LAL) pattern in HEp-2 cells (57.7% - 41/71). Biofilm production was observed in 33.8% (24/71) of EPEC isolates, and it means statistically significant association with shf gene (p = 0.0254). The highest antimicrobial resistance rates and a large number of multiresistant isolates 67.6% (48/71), regarded cefuroxime (CXM), ampicillin (AMP), trimethoprim-sulfamethoxazole (SXT) and tetracycline (TET), respectively, mainly in typical EPEC (tEPEC). Furthermore, 96% (68/71) of EPEC isolates in the present study were resistant to at least one antibiotic, whereas only 3 isolates were sensitive to all the tested drugs.

Conclusion: Based on our findings, there was increased aEPEC identification. EPEC isolates showed high resistance rate; most strains showed multiresistance; thus, they work as warning about the continuous need of surveillance towards antimicrobial use. Besides, the ability of forming biofilm was evidenced by the EPEC isolates. This outcome is worrisome, since it is a natural resistance mechanism of bacteria.