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Background: Shigella species are among the common causes of bacterial diarrhoeal diseases. Traditional detection methods are time-consuming resulting in delay in treatment and control of Shigella infections thus there is a need to develop molecular methods for rapid and simultaneous detection of Shigella spp. In this study a rapid multiplex PCR were developed for simultaneous detection of three pathogenic Shigella species., Methods: For detection of Shigella spp., a pair of primers was used to replicate a chromosomal sequence. Three other sets of primers were also designed to amplify the target genes of three most common species of Shigella in Iran including S. sonnei, S. flexneri and S. boydii. The multiplex PCR assay was optimized for simultaneous detection and differentiation of three pathogenic Shigella species. The assay specificity was investigated by testing different strains of Shigella and other additional strains belonging to non Shigella species, but responsible for foodborne diseases., Results: The Shigella genus specific PCR yielded the expected DNA band of 159 bp in all tested strains belonging to four Shigella species. The standard and multiplex PCR assays also produced the expected fragments of 248 bp, 503 bp, and 314 bp, for S. boydii, S. sonnei and S. flexneri, respectively. Each species-specific primer pair did not show any cross-reactivity., Conclusion: Both standard and multiplex PCR protocols had a good specificity. They can provide a valuable tool for the rapid and simultaneous detection and differentiation of three most prevalent Shigella species in Iran.

Introduction: Several factors have been suggested to account for differences in the virulence of Helicobacter pylori infections in various populations. Evidence suggests the existence of different strains of H. pylori with different degrees of virulence. The present study aimed to investigate the gastric histopathology in Iranian patients infected with H. pylori and to investigate the relationship between the severity of gastritis and four different bacterial virulence-associated genotypes., Methods and Materials: All of the patients with positive results from a pathological examination, a rapid urease test, and PCR analysis for H. pylori infection were consecutively included into the study. The classification and grading of gastritis were performed according to the Sydney System. Esophagitis was classified endoscopically according to the Savary-Miller grading system. The primers used in this study targeted 16S rRNa (521 bp), Urease A (411 bp), Cag A (400 bp), and 26 kDa (303 bp)., Results: Twenty-eight patients were included in the study. The presence of Cag A showed a significant relationship with higher gastritis grades (3.0±0.7 vs. 2.3±0.9, p=0.024) and higher scores for H. pylori infection (3.0±0.7 vs. 2.3±0.7, p=0.027). The patients infected with 26 kDa-positive H. pylori had significantly higher infection scores (3.5±0.6 vs. 2.5±0.6, p=0.020)., Conclusion: This study showed that CagA-positive H. pylori infection is associated with more severe gastritis and with increased bacterial density and inflammation in the biopsy specimens. The 303-bp positive genotype was also significantly associated with higher grades of esophagitis. Additional in-depth trials will be helpful in extending our findings., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

Salmonella enterica has become progressively resistant to antimicrobial agents worldwide as a result of genes carried on different classes of integrons. The aim of the current study was to investigate the molecular diversity of these integrons and their association with antimicrobial resistance in clinical S. enterica isolates from Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Integrons were detected in 65 (47.1%) strains, with classes 1 and 2 being observed in 54 (39%) and 11 (8%) strains, respectively. Integron-positive isolates belonged to seven different S. enterica serovars, and all showed a multidrug-resistant (MDR) phenotype. Our findings show that integrons are widely disseminated among S. enterica strains from Tehran. Furthermore, the results that class 1 integrons were more prevalent than class 2 in Salmonella isolates, and that a statistical association with MDR patterns was observed, suggest that they are more likely to be important in conferring a resistant phenotype to Salmonella strains.