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Diversity of Variable Number Tandem Repeat Loci in Shigella Species Isolated from Pediatric Patients.

Ranjbar R, Memariani M, Memariani H - Int J Mol Cell Med (2015)

Bottom Line: All isolates were identified by routine biochemical and serological tests.Almost all the isolates were classified into five clonal complexes.Furthermore, our MLVA assay could effectively distinguish the four Shigella species.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.

ABSTRACT
Multilocus variable number tandem repeat (VNTR) analysis (MLVA) is a new typing method with several advantages compared to other methods. Dissemination of Shigella is highly significant in developing countries. Whilst Shigella is becoming increasingly important as an etiologic agent of pediatric shigellosis in Iran, little is known about the genetic diversity of the local strains. Therefore, the aim of this study was to describe the genetic diversity of Shigella species isolated from pediatric patients in Tehran, Iran. A total of 53 Shigella isolates were obtained from 1070 patients with diarrhea (less than 12 years of age). All isolates were identified by routine biochemical and serological tests. The confirmed Shigella isolates were further serogrouped (by the slide agglutination) using slide agglutination method. MLVA assay with the seven loci resolved 53 Shigella isolates into 36 different genotypes. Almost all the isolates were classified into five clonal complexes. Furthermore, our MLVA assay could effectively distinguish the four Shigella species. This study has provided valuable insights into the genetic heterogeneity of Shigella species in Tehran, Iran. Our findings can be helpful for further epidemiological surveillance of Shigella species in this country in the future.

No MeSH data available.


Related in: MedlinePlus

UPGMA analysis of Shigella isolates based on VNTR profiles. The highlighted colors represent Shigella species. S. flexneri Sf2457T [serotype 2a] was also used as an outgroup
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Figure 3: UPGMA analysis of Shigella isolates based on VNTR profiles. The highlighted colors represent Shigella species. S. flexneri Sf2457T [serotype 2a] was also used as an outgroup

Mentions: Of the 53 Shigella isolates, S. sonnei (50.9%, n= 27) was the most common, followed by S. flexneri (35.8%, n= 19), S. boydii (9.4%, n= 5), and S. dysenteriae (3.8%, n= 2). The age distribution data revealed that Shigella was isolated from 40 (75.5%) cases in the 2-5 year-old, 11 (20.7%) in the 6-12 year-old and 2 (3.8%) in ≤ one year-old age groups. Furthermore, this difference was statistically significant (P< 0.001), suggesting that the peak age of shigellosis was 2-5 years in children. MLVA based on seven VNTR loci was carried out to characterize the Shigella isolates (Figure 1). Overall, Shigella isolates were discriminated into 36 different MLVA types (genotypes). Almost all of the strains were classified into five clonal complexes (CCs). CCs are defined as a group of allelic profiles in which every profile shares at least 5 loci in common with at least an other member of the group. MST analysis showed that most of the S. sonnei strains fell into one CC (i.e. CC2), whereas most of the S. flexneri strains were categorized into three CCs (i.e. CC1, CC3, and CC5) (Figure 2). The UPGMA dendrogram with detail information including isolate code, species, and allelic profile is shown in Figure 3. All the Shigella isolates were categorized into two main clusters (i.e. cluster A and cluster B). Cluster A consisted of two subclusters, which represented most of our isolates (n=47). Interestingly, subcluster A1 contains only S. sonnei isolates, whereas subcluster A2 is relatively diverse. Cluster B only includes some strains of S. boydii and S. flexneri.


Diversity of Variable Number Tandem Repeat Loci in Shigella Species Isolated from Pediatric Patients.

Ranjbar R, Memariani M, Memariani H - Int J Mol Cell Med (2015)

UPGMA analysis of Shigella isolates based on VNTR profiles. The highlighted colors represent Shigella species. S. flexneri Sf2457T [serotype 2a] was also used as an outgroup
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644529&req=5

Figure 3: UPGMA analysis of Shigella isolates based on VNTR profiles. The highlighted colors represent Shigella species. S. flexneri Sf2457T [serotype 2a] was also used as an outgroup
Mentions: Of the 53 Shigella isolates, S. sonnei (50.9%, n= 27) was the most common, followed by S. flexneri (35.8%, n= 19), S. boydii (9.4%, n= 5), and S. dysenteriae (3.8%, n= 2). The age distribution data revealed that Shigella was isolated from 40 (75.5%) cases in the 2-5 year-old, 11 (20.7%) in the 6-12 year-old and 2 (3.8%) in ≤ one year-old age groups. Furthermore, this difference was statistically significant (P< 0.001), suggesting that the peak age of shigellosis was 2-5 years in children. MLVA based on seven VNTR loci was carried out to characterize the Shigella isolates (Figure 1). Overall, Shigella isolates were discriminated into 36 different MLVA types (genotypes). Almost all of the strains were classified into five clonal complexes (CCs). CCs are defined as a group of allelic profiles in which every profile shares at least 5 loci in common with at least an other member of the group. MST analysis showed that most of the S. sonnei strains fell into one CC (i.e. CC2), whereas most of the S. flexneri strains were categorized into three CCs (i.e. CC1, CC3, and CC5) (Figure 2). The UPGMA dendrogram with detail information including isolate code, species, and allelic profile is shown in Figure 3. All the Shigella isolates were categorized into two main clusters (i.e. cluster A and cluster B). Cluster A consisted of two subclusters, which represented most of our isolates (n=47). Interestingly, subcluster A1 contains only S. sonnei isolates, whereas subcluster A2 is relatively diverse. Cluster B only includes some strains of S. boydii and S. flexneri.

Bottom Line: All isolates were identified by routine biochemical and serological tests.Almost all the isolates were classified into five clonal complexes.Furthermore, our MLVA assay could effectively distinguish the four Shigella species.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.

ABSTRACT
Multilocus variable number tandem repeat (VNTR) analysis (MLVA) is a new typing method with several advantages compared to other methods. Dissemination of Shigella is highly significant in developing countries. Whilst Shigella is becoming increasingly important as an etiologic agent of pediatric shigellosis in Iran, little is known about the genetic diversity of the local strains. Therefore, the aim of this study was to describe the genetic diversity of Shigella species isolated from pediatric patients in Tehran, Iran. A total of 53 Shigella isolates were obtained from 1070 patients with diarrhea (less than 12 years of age). All isolates were identified by routine biochemical and serological tests. The confirmed Shigella isolates were further serogrouped (by the slide agglutination) using slide agglutination method. MLVA assay with the seven loci resolved 53 Shigella isolates into 36 different genotypes. Almost all the isolates were classified into five clonal complexes. Furthermore, our MLVA assay could effectively distinguish the four Shigella species. This study has provided valuable insights into the genetic heterogeneity of Shigella species in Tehran, Iran. Our findings can be helpful for further epidemiological surveillance of Shigella species in this country in the future.

No MeSH data available.


Related in: MedlinePlus