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Showing 2 results for Zahraei Salehi
In vitro Susceptibility Study of Salmonella typhimurium Mutant to Stress Factors
Ania Ahani Azari , Taghi Zahraei Salehi , Bahar Nayeri Fasaei ,
Volume 10, Issue 6 (Nov-Dec-2016 2016)
Abstract

ABSTRACT

        Background and Objective: In this study, we compared the susceptibility of Salmonella typhimurium phoP mutant and its parent to stress conditions that the pathogen may encounter in a host.

        Methods: For this purpose, we used the phoP deletion mutant constructed in our previous study. In order to test the in vitro susceptibility of the mutant to stress factors, the effect of acidic pH, heat, bile salts and polymyxin on growth of the mutant was examined. Then, minimum inhibitory concentration and minimum bactericidal concentration of bile salts and polymyxin were determined. Salmonella typhimurium 14028 was used as the parent strain.

         Results: The mutant was highly susceptible to bile salts and polymyxin in comparison with the parent strain, but no difference was observed in their susceptibility to acid and heat.

          Conclusion: This study confirms the role of the phoP in resistance of Salmonella to polymyxin and bile salts. Mutation in the phoP leads to susceptibility of the mutant to bile and cationic antimicrobial peptides.

         Keywords: In vitro, Mutant, Salmonella typhimurium, Disease Susceptibility.


Optimum cultural conditions to achieve the best biofilm formation and high level icaA transcription by Staphylococcus aureus
Dr Aram Sharifi, Dr Abdolmajid Mohammadzadeh, Dr Pezhman Mahmoodi, Prof Taghi Zahraei Salehi,
Volume 20, Issue 2 (6-2026)
Abstract
Abstract
Background: Biofilm formation in Staphylococcus aureus (S. aureus), mediated by the ica operon, is a key virulence factor. This study examined how different glucose-supplemented broth culture media influence biofilm production and ica gene expression in S. aureus.
Methods: The phenotypic ability to adhere to a polystyrene surface and to produce slime layer were evaluated using microtiter plate test (MtP) and Congo red tube test, respectively. Using PCR, the presence of intercellular adhesion (ica) locus in S. aureus strains was confirmed and subsequently, quantitative real-time RT-PCR was performed to investigate transcription of icaA in various media including Tryptic soy broth (TSB), Brain-heart infusion broth (BHIB), (Nutrient broth) NB and (Muller-Hinton broth) MHB contained 0, 0.25, 0.5, 1 and 2% glucose.
Results: Our results showed that although all of the studied strains adhered to the wells of polystyrene microtiter plates, the optimum rate of biofilm formation was observed for TSB medium contained 1% glucose, but biofilm formation was not significantly different in NB, MHB and BHIB media. Supplementation of all media with 1% glucose led to the highest production of biofilm formation and in all media transcription of icaA was increased with glucose addition to one present.
Conclusions: The results of the present study indicated that TSB medium supplemented with 1% glucose was the most appropriate medium for evaluation of biofilm formation by S. aureus isolates.
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