The antibiotic resistance and virulence factors of Escherichia coli of serogroup O1 isolated from Tehran, Iran
Authors: Majid Eslami, Shahin Najar-Peerayeh, Amin Talebi Bezmin Abadi, Bita Bakhshi, Shirin Afhami
Number of views: 50
Objective: To detect several virulence genes among Escherichia coli (E. coli) isolates of
serogroup O1 collected in Tehran, Iran.
Methods: In this study, 100 clinical isolates of E. coli were collected in Tehran, Iran. The
antibiotic susceptibility test was done for 14 antibiotics according to CLSI guidelines.
Phylogenetic grouping was performed by PCR according to the chuA, yjaA and TspE4.C2
genes. Serogroup typing was performed using the 12 O-antigens. The virulence genes were
detected by PCR.
Results: A total of 37 isolates belonged to serogroup O1. All of E. coli isolates were sensitive
to phosphomycin. Phylogroups A (30%), B1 (21%), B2 (39%), and D (10%) were detected.
The prevalence rates of cnf, cdt, iutA, csgA, kpsMII, ibeA, vat, traT, TcpC, sat, hlyA and pic
were 19%, 8%, 78%, 84%, 43%, 8%, 16%, 81%, 0%, 38%, 92% and 8%, respectively. Also,
the vat gene was the most dominant gene in A phylogroup, and the genes of sat and pic were
the most dominant virulence genes in the B2 phylogroup.
Conclusions: The phosphomycin, imipenem, and meropenem were the most effective
antibiotics. Half of the isolates were multidrug resistant. The predominant virulence factors of
E. coli isolates were the genes hlyA, iutA, traT, and csgA. Detection of virulent strains which
exhibit wide antibiotic resistance can help the control programs in order to prevent the spread
of infections. According to the results, the B2 phylogroup was the most common phylogroup
and strains belonging to B1 phylogroup were the most resistant strains in O1 serogroup E. coli