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Updated: Jul 16, 2025
Author Spotlight: Advancements in Understanding and Combatting Shigella Infections
Published on: February 9, 2024
Invasion of HeLa Cells by Shigella Species Clinical Isolates Recovered from Pediatric Diarrhea
Zohreh Ghalavand1, Marzieh Taheri1,2, Gita Eslami1
1Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Insights
Shigella bacteria, a concern for children, invade host cells. This study found Shigella flexneri isolates showed higher invasion than Shigella sonnei, linked to specific virulence genes.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Biology
Background:
- Shigella poses a significant public health threat, particularly to young children in developing nations.
- Shigella pathogenicity involves complex interactions of chromosomal and plasmid-encoded virulence factors.
- Understanding factors influencing Shigella invasion is crucial for managing shigellosis.
Purpose of the Study:
- To investigate how Shigella spp. isolates from pediatric patients in Tehran, Iran, with varying characteristics, affect HeLa cell invasion.
- To correlate serogroups, virulence gene profiles, and antibiotic resistance patterns with the cell invasion capabilities of Shigella isolates.
Main Methods:
- Ten Shigella isolates (Shigella flexneri and Shigella sonnei) from pediatric patients were analyzed.
- Virulence gene profiling (virA, sen, ipgD, ipaD, ipaC, ipaB, ipaH) and antibiotic resistance patterns were determined.
- Cell invasion ability was quantified using a plaque-forming assay in HeLa cell lines.
Main Results:
- All tested Shigella spp. isolates demonstrated the ability to invade HeLa cells.
- Significant variations in plaque number and size were observed among different isolates.
- Shigella flexneri isolates exhibited higher invasion efficiency compared to Shigella sonnei isolates.
Conclusions:
- The invasion capacity of Shigella isolates in HeLa cells is influenced by their characteristics, including serogroup and specific virulence genes.
- While Shigella flexneri's enhanced invasion is linked to certain virulence genes, their precise roles require further investigation.
- These findings contribute to understanding the molecular basis of Shigella pathogenesis and host cell interaction.
Abstract:
Shigella is considered a major public health concern, especially for children younger than 5 years of age in developing countries. The pathogenicity of Shigella is a complex process that involves the interplay of multiple genes located on a large, unstable virulence plasmid as well as chromosomal pathogenicity islands. Since various factors (including virulence and antibiotic resistance genes) are associated with the severity and duration of shigellosis, in this article, we aim to evaluate whether the invasion of HeLa cells is affected by Shigella spp. isolates with different characteristics (including serogroups, virulence gene profiles, and antibiotic resistance patterns) recovered from pediatric patients in Tehran, Iran. Cell invasion ability of 10 Shigella isolates with different serogroups (Shigella flexneri and Shigella sonnei), gene profiling (virA, sen, ipgD, ipaD, ipaC, ipaB, and ipaH), and antibiotic resistance phenotyping (ampicillin, azithromycin, ciprofloxacin, nalidixic acid, trimethoprim-sulfamethoxazole, cefixime, cefotaxime, minocycline, and levofloxacin) were measured by plaque-forming assay in HeLa cell lines. The results show that all the selected Shigella spp. isolates recovered from pediatric patients were able to invade HeLa cells, but the total number and average size of plaques were different between the isolates. The higher invasion ability of S. flexneri isolates in HeLa cells compared to S. sonnei isolates was attributed to the presence of particular virulence genes; however, the role of each of these virulence factors remains to be determined.
