Sequence-subtype association of multi-drug-resistant diarrheagenic Escherichia coli

Nastaran Farzi; Zahra Pourramezan; Fatemeh  Akhavan Attar; Saeid Mostaan; Mana Oloomi

doi:10.18502/ijm.v16i2.15350

Nastaran Farzi Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
Zahra Pourramezan Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
Fatemeh Akhavan Attar Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
Saeid Mostaan Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
Mana Oloomi Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran

DOI: https://doi.org/10.18502/ijm.v16i2.15350

Keywords: Escherichia coli; Multilocus sequence typing; Multidrug resistant; β-lactams; Virulence factors

Abstract

Background and Objectives: Multi-drug-resistant pathogens pose a significant threat as they can rapidly spread, leading to severe healthcare-associated invasive infections. In developing countries, diarrheagenic Escherichia coli (DEC) is a major bacterial pathogen responsible for causing diarrhea. However, the outbreak of resistant strains has made the treatment of DEC infections much more challenging. This study aimed to investigate the relationship between antibiotic resistance genes and other virulence categories in E. coli strains that cause diarrhea, particularly DEC.

Materials and Methods: The phylogenetic grouping was defined using PCR and multi-locus sequence type (MLST) meth- ods.

Results: Among the isolates analyzed, 14 were identified as resistant and were classified into eight distinct sequence types: ST3, ST53, ST77, ST483, ST512, ST636, ST833, and ST774, indicating genetic diversity among the resistant strains. Certain sequence types, notably ST512 and ST636, were found to be associated with multiple antibiotic resistance in DEC. Regard- ing antibiotic susceptibility, strains showed the highest resistance to amoxicillin, suggesting that this antibiotic may not be effective in treating DEC infections. On the other hand, the isolates demonstrated susceptibility to amikacin and chloram- phenicol, implying that these antibiotics could be more suitable treatment options for DEC infections.

Conclusion: The findings underscore the importance of promptly identifying antibiotic resistance patterns and their correla- tion with specific pathogenic virulence categories, as this knowledge can aid in selecting the most appropriate antibiotics for treating DEC infections. Considering the antibiotic resistance profiles and associated resistance genes is crucial in managing and containing diarrheal outbreaks and in selecting effective antibiotic therapies for DEC infections.