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Mohammad Mehdi Soltan Dallal 2 Articles
Profiling of Virulence-associated Factors in Shigella Species Isolated from Acute Pediatric Diarrheal Samples in Tehran, Iran
Sajad Yaghoubi, Reza Ranjbar, Mohammad Mehdi Soltan Dallal, Somayeh Yasliani Fard, Mohammad Hasan Shirazi, Mahmood Mahmoudi
Osong Public Health Res Perspect. 2017;8(3):220-226.   Published online June 30, 2017
DOI: https://doi.org/10.24171/j.phrp.2017.8.3.09
  • 2,369 View
  • 31 Download
  • 14 Citations
AbstractAbstract PDF
Objectives

The genus Shigella comprises the most infectious and diarrheagenic bacteria causing severe diseases, mostly in children under five years of age. This study aimed to detect nine virulence genes (ipaBCD, VirA, sen, set1A, set1B, ial, ipaH, stx, and sat) in Shigella species (spp.) using multiplex polymerase chain reaction (MPCR) and to determine the relation of Shigella spp. from pediatric diarrheal samples with hospitalization and bloody diarrhea in Tehran, Iran.

Methods

Shigella spp. were isolated and identified using standard microbiological and serological methods. The virulence genes were detected using MPCR.

Results

Seventy-five Shigella spp. (40 S. sonnei, 33 S. flexneri, 1 S. dysenteriae, and 1 S. boydii) were isolated in this study. The prevalence of ial, sen, sat, set1A, and set1B was 74.7%, 45.4%, 28%, 24%, and 24%, respectively. All S. flexneri isolates, while no S. sonnei, S. dysenteriae, or S. boydii isolates, contained sat, set1A, and set1B. All isolates were positive for ipaH, ipaBCD, and virA, while one (1.4%) of the isolates contained stx. The highest prevalence of virulence determinants was found in S. flexneri serotype IIa. Nineteen (57.6%) of 33 S. flexneri isolates were positive for ipaBCD, ipaH, virA, ial, and sat. The sen determinants were found to be statistically significantly associated with hospitalization and bloody diarrhea (p = 0.001).

Conclusion

This study revealed a high prevalence of enterotoxin genes in S. flexneri, especially in serotype 2a, and has presented relations between a few clinical features of shigellosis and numerous virulence determinants of clinical isolates of Shigella spp.

The Effect of Lactobacillus acidophilus PTCC 1643 on Cultured Intestinal Epithelial Cells Infected with Salmonella enterica serovar Enteritidis
Mona Moshiri, Mohammad Mehdi Soltan Dallal, Farhad Rezaei, Masoumeh Douraghi, Laleh Sharifi, Zahra Noroozbabaei, Mehrdad Gholami, Abbas Mirshafiey
Osong Public Health Res Perspect. 2017;8(1):54-60.   Published online February 28, 2017
DOI: https://doi.org/10.24171/j.phrp.2017.8.1.07
  • 2,110 View
  • 19 Download
  • 7 Citations
AbstractAbstract PDF
Objectives

Gastrointestinal disorders caused by Salmonella enterica serovar Enteritidis (SesE) are a significant health problem around the globe. Probiotic bacteria have been shown to have positive effects on the immune responses. Lactobacillus acidophilus was examined for its capability to influence the innate immune response of HT29 intestinal epithelial cells towards SesE. The purpose of this work was to assess the effect of L. acidophilus PTCC 1643 on cultured intestinal epithelial cells infected with SesE.

Methods

HT29 cells were cultured in Roswell Park Memorial Institute medium supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. The cells were treated with L. acidophilus PTCC 1643 after or before challenge with SesE. At 2 and 4 hours post-infection, we measured changes in the expression levels of TLR2 and TLR4 via real-time polymerase chain reaction.

Results

Treatment with L. acidophilus inhibited SesE-induced increases in TLR2 and TLR4 expression in the infected HT29 cells. Moreover, the expression of TLR2 and TLR4 in cells that were pretreated with L. acidophilus and then infected with SesE was significantly higher than that in cells infected with SesE without pretreatment. Taken together, the results indicated that L. acidophilus had an anti-inflammatory effect and modulated the innate immune response to SesE by influencing TLR2 and TLR4 expression.

Conclusion

Our findings suggested that L. acidophilus PTCC 1643 was able to suppress inflammation caused by SesE infection in HT29 cells and reduce TLR2 and TLR4 expression. Additional in vivo and in vitro studies are required to further elucidate the mechanisms underlying this anti-inflammatory effect.

Mohammad Mehdi Soltan Dallal 1 Article
Identification of Klebsiella pneumoniae Carbapenemase-producing Klebsiella oxytoca in Clinical Isolates in Tehran Hospitals, Iran by Chromogenic Medium and Molecular Methods
Majid Validi, Mohammad Mehdi Soltan Dallal, Masoumeh Douraghi, Jalil Fallah Mehrabadi, Abbas Rahimi Foroushani
Osong Public Health Res Perspect. 2016;7(5):301-306.   Published online October 31, 2016
DOI: https://doi.org/10.1016/j.phrp.2016.08.006
  • 1,309 View
  • 25 Download
  • 8 Citations
AbstractAbstract PDF
Objectives
Production of carbapenemase, especially Klebsiella pneumoniae carbapenemases (KPC), is one of the antibiotic resistance mechanisms of Enterobacteriaceae such as Klebsiella oxytoca. This study aimed to investigate and identify KPC-producing K. oxytoca isolates using molecular and phenotypic methods.
Methods
A total of 75 isolates of K. oxytoca were isolated from various clinical samples, and were verified as K. oxytoca after performing standard microbiological tests and using a polymerase chain reaction (PCR) method. An antibiotic susceptibility test was performed using a disc diffusion method according to the Clinical and Laboratory Standards Institute guidelines. CHROMagar KPC chromogenic culture media was used to examine and confirm the production of the carbapenemase enzyme in K. oxytoca isolates; in addition, PCR was used to evaluate the presence of blaKPC gene in K. oxytoca strains.
Results
Of a total of 75 K. oxytoca isolates, one multidrug resistant strain was isolated from the urine of a hospitalized woman. This strain was examined to assess its ability to produce carbapenemase enzyme; it produced a colony with a blue metallic color on the CHROMagar KPC chromogenic culture media. In addition, the blaKPC gene was confirmed by PCR. After sequencing, it was confirmed and deposited in GenBank.
Conclusion
To date, many cases of KPC-producing Enterobacteriaceae, in particular K. pneumoniae, have been reported in different countries; there are also some reports on the identification of KPC-producing K. oxytoca. Therefore, to prevent the outbreak of nosocomial infections, the early detection, control, and prevention of the spread of these strains are of great importance.

PHRP : Osong Public Health and Research Perspectives