<p>Distribution of Genes Encoding Virulence Factors and the Genetic Diversity of Enteroinvasive <em>Escherichia coli</em> (EIEC) Isolates from Patients with Diarrhea in Ahvaz, Iran</p>

Abstract

Background: Entero-invasive E. coli (EIEC) is one of the causes of bacillary dysentery in adults and children. The ability of EIEC to invade and colonize the surface of epithelial cells is influenced by many virulence factors. This study aimed to investigate the distribution of virulence factor genes in EIEC strains isolated from patients with diarrhea in Ahvaz, Iran, as well as the genetic diversity between these isolates by Multilocus variable-number tandem repeat analysis (MLVA). Materials and Methods: A total of 581 diarrheic stool samples were collected from patients with diarrhea attending two hospitals, in Ahvaz, Iran. The E. coli strains were identified by biochemical methods. Subsequently, all E. coli isolates were identified as EIEC by polymerase chain reaction (PCR) for the ipaH gene. The EIEC isolates evaluated by PCR for the presence of 8 virulence genes (ial, sen, virF, invE, sat, sigA, pic, and sepA). All EIEC strains were genotyped by the MLVA typing method. Results: A total of 13 EIEC isolates were identified. The presence of ial, virF, invE, sen, sigA, pic, and sat genes was confirmed among 92.3%, 84.6%, 84.6%, 76.9%, 69.2%, and 15.3% of EIEC isolates, respectively. On the other hand, none of the isolates were positive for the sepA gene. The EIEC isolates were divided into 11 MLVA types. Conclusion: Our results showed a high distribution of virulence genes among EIEC isolates in our region. This study showed that MLVA is a promising typing technique for epidemiological studies. MLVA can supply data in the form of codes that can be saved in the database and easily shared among laboratories, research institutes, and even hospitals.

Distribution of genes encoding virulence factors of Shigella strains isolated from children with diarrhea in southwest Iran

“…The sequences of primers and annealing temperatures of the ipaH gene are shown in Table 1. PCR conditions were examined according to the protocol as described previously [6]. S. exnery ATCC 12122 was used as a positive PCR control for the ipaH gene.…”

“…S. sonnei ATCC25931, S. exneri ATCC29903, S. boydii ATCC8700, and S. dysenteriae ATCC13313 were used as a positive control. Ampli cation of virulence factors genes PCR was performed for all Shigella strains to evaluate the prevalence of the ial, virF, invE, pet, sat, sigA, pic, and sepA [6,9]. The sequences of primers and annealing temperatures are shown in Table 1.…”

“…Class 1 SPATEs members include the plasmid-encoded toxin gene (pet), secreted autotransporter toxin gene (sat), and Shigella IgA-like protease homolog gene (sigA), which are cytotoxic for epithelial cells. The protease involved in colonization of the intestine (pic) and the extracellular protein Shigella A (sepA) are members of class 2, which contribute to intestinal in ammation and colonization [6]. Shigella isolates harboring virulence genes can induce extensive mucosal damages and in ammation in intestinal cells, especially when these strains encode more than one of the virulence factors.…”

Virulence factors of Enteric Pathogenic Escherichia coli: A Review

“…IpaH7.8, IpaB, IpaD and IpaC also have been implicated in phagosome escape [82]. VirG nucleates actin by inducing the acquisition of N-WASP, contributing to ARP2/3 formation and mediated unipolar actin tail formation on the surface of the bacteria [83]. IpaC also activates SRC-family protein kinases to recruit the ARP2/3 complex at the site of the bacterial contact and induces actin polymerization to form a ruffle for bacterial entry.…”

Distribution of Genes Encoding Virulence Factors of Shigella Strains Isolated from Children with Diarrhea in Southwest Iran.

“…S. sonnei ATCC25931, S. exneri ATCC29903, S. boydii ATCC8700, and S. dysenteriae ATCC13313 were used as a positive control. Ampli cation of virulence factors genes PCR was performed for all Shigella strains to evaluate the prevalence of the ial, virF, invE, pet, sat, sigA, pic, and sepA [6,9]. The sequences of primers and annealing temperatures are shown in…”