Baban Zadeh, P.

Esmaeili, D.

Khaledi, A.

kashan university of medical sciences

  
Iran J Public Health, Vol. 48, No.7, Jul 2019, pp.1390-1391                                          Letter to the Editor 
1390                                                                                                      Available at:    http://ijph.tums.ac.ir 
 
 
Satureja khuzestanica Essential Oil against Quorum Sensing of 
Pseudomonas aeroginosa Using RT-PCR 
 
Parya BABAN ZADEH 1, Azad KHALEDI 2, *Davoud ESMAEILI 3,4 
 
1. Department of Microbiology, Faculty of Pharmaceutical Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran 
2. Department of Microbiology and Immunology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran 
3. Department of Microbiology and Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of 
Medical Sciences, Tehran, Iran 
4. Applied Virology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran        
 
*Corresponding Author: Email: esm114@gmail.com 
 
(Received 09 Aug 2018; accepted 24 Aug 2018) 
 
Dear Editor-in-Chief  
 
Pseudomonas aeruginosa is considered as an im-
portant opportunist nosocomial pathogen, which 
in fact is highly resistant to most common antibi-
otics. For this reason, the treatment of infections 
resulted from this pathogen (P.aeruginosa) creates 
many problems (1,2). Different virulence factors 
(VFs) are produced by this bacterium which most 
of these extracellular VFs are synthesized under 
regulatory systems of Quorum sensing (3). Quor-
um sensing makes the connection between bacte-
ria. This allows intra-isolates as well as inter-
isolates connections among bacteria. There are 
two systems of Quorum sensing, such as rhl and 
las, in P. aeruginosa. These are known systems 
used to control the expression of some virulence 
genes (4). 
Carvacrol is considered as one of the most effec-
tive compounds of Satureja khuzestanica, which 
affects membrane, protein, and genes. This can 
affect the electron transport chain, and even can 
be used as food (5,6). Therefore, this study aimed 
to assess the inhibitory effects of carvacrol on the 
expression of quorum sensing of P. aeruginosa us-
ing RT-PCR.  
The shoot parts of S. khuzestanica were collected 
over the third months of spring (2013) from 
Lorestan Province, Iran and its essence were ex-
tracted and analyzed to evaluate its antimicrobial 
activity by Microdilution method. Minimum In-
hibitory Concentration (MIC) essence was per-
formed in accordance with the Clinical & Labora-
tory Standards Institute (CLSI) 2013 guidelines. 
To analyze the expression of quorum sensing, 
mRNA of the P. aeruginosa isolates (recovered 
from Motahari Hospital, Tehran) was extracted 
and cDNA synthesized, and RT-PCR reaction 
performed using kit (Cinnagen Company, Iran). 
Combination of materials for the reaction was as 
follows; Primers (Forward, Reverse) and DNA 
sample: 1µL; Master mix: 12.5; distilled water 
(DDW): 9.5 µL in final volume: 25 µL. The pro-
gram of PCR reaction was; Hot start 3 min at 95 
°C for 1 cycle, denaturation 30 sec at 95 °C, then, 
35 cycles at 54 °C for 30 sec and at 72 °C for 1 
min; finally, at 72 °C for 10 min.  
Finally, results analyzed using SPSS software (ver. 
22, Chicago, II, USA) and non-parametric statis-
tical test (Kruskal Wallis) and P-value less than 
P<0.05 was considered significant. 
The results of susceptibility testing showed that 
all 5 isolates were resistant against Gentamycin, 
Tobramycin, and Ciprofloxacin and all of those 
were susceptible to Polymyxin B and 50% of iso-
lates were resistant to Amikacin. The essence has 
a favorable anti-bacterial effect.  
The amount of MIC, for all 5 isolates, based on 
Microdilution method and according to CLSI 
was 31% (3.1 mg/mL). Moreover, the expression 
Baban Zadeh et al.: Satureja khuzestanica Essential Oil against Quorum Sensing … 
Available at:    http://ijph.tums.ac.ir                                                                                                                     1391 
of ‘(QS)’ gene was decreased after treatment with 
S.Khuzestanica, whereas, the expression of the 
gyrA gene had remained constant throughout the 
study (Fig. 1). 
 
 
 
Fig. 1: RT-PCR results for expression of ‘(QS)’ and 
gyrA genes after treatment with Satureja Khuzestanica, 
B.T: Before treatment, A.T: After treatment 
 
The bacteria can communicate with each other 
through the phenomenon of Quorum sensing (-
QS) and adapt themselves to genomic expression 
patterns in case of environmental changes. 
Moreover today, with restrictive QS, anti-
bacterial drugs produce (7,8) in the control of 
infections in medical, agricultural and industrial 
applications (9). We believe that some of the an-
timicrobial properties of HSMP may be contrib-
uted by the QS inhibiting phytochemicals present 
in it.  
In this study, the RT-PCR technique was utilized 
to survey the effect of S. khuzestanica essence on 
the expression of Quorum sensing pathogenic 
gene. Herbal essence is one of the potential 
sources of anti-bacterial compounds and useful in 
making antimicrobial compounds. Therefore, the 
present study introduced this compound as a 
medicine and health supplement to inhibit 
P.aeruginosa. S. khuzestanica has an inhibitory effect 
on the expression of quorum sensing of P. aeru-
ginosa.  
The essence of S. khuzestanica reduced the expres-
sion of quorum sensing during 24 h. Therefore, 
this essence is effective against P. aeruginosa due to 
inhibition of gene expression of P. aeruginosa and 
anti-bacterial effect. 
 
Acknowledgements 
 
We would like to thank our colleagues in the 
medical laboratory of Motahari hospital. 
 
Conflict of interest 
 
The authors declare that there is no conflict of 
interest. 
 
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Satureja khuzestanica essential oil against quorum sensing of pseudomonas aeroginosa using RT-PCR

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Satureja khuzestanica essential oil against quorum sensing of pseudomonas aeroginosa using RT-PCR

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