The Effect of Molecular Template Nanopolymer-zinc oxide (Zn) Nanoparticles Impregnated with Khuzestani Essential Oil on lasR Gene Expression in Clinical Isolates of Pseudomonas aeruginosa: a laboratory study

In the present study, as a research background, the application of nanoparticles and herbal medicines in the treatment of diseases caused by Pseudomonas aeruginosa was investigated. The aim of this study was to determine the effect of zinc nanoparticles (Zn) impregnated with Khuzestan savory (Satureja khuzestanica) essential oil on the expression of lasR gene in clinical isolates of Pseudomonas aeruginosa, which are biofilm-forming bacteria, under extracellular conditions.

The present experimental study was conducted in 2019 on 150 non-repetitive and intermittent clinical samples suspected of Pseudomonas aeruginosa, which were collected from skin, blood, and urine samples of hospitalized patients in various wards of Imam Sajjad (AS) Hospital in Yasuj city. After the entry of 4 clinical strains along with a standard strain of Pseudomonas aeruginosa (ATCC 25922) as a sample, Khuzestan savory essential oil was prepared from Barij Essence Pharmaceutical Company (Kashan, Iran). Then, after identifying the Pseudomonas aeruginosa sample separated from the patients, PCR was performed to confirm the presence of lasR and DNA gyrase A genes, determine the antibiotic sensitivity pattern, broth microdilution test, checkerboard dilution, and agar test to determine the minimum inhibitory concentration, and real-time PCR to investigate the expression of lasR gene under laboratory conditions. The collected data were analyzed using Mann-Whitney U, T-Test, and Paired T-Test statistical tests.

According to the results of the antibiotic sensitivity pattern, the highest resistance was related to amikacin (30 μg), colistin (10 μg), and ciprofloxacin (5 μg), and the lowest resistance was related to ceftazidime (30 μg) and imipenem (10 μg). Also, Khuzestan savory essential oil and zinc oxide nanoparticles had a minimum inhibitory concentration of 256-512 μg/mL against standard strains and clinical isolates. The relative minimum inhibitory concentration index (FIC) was equal to 1, which represents an increase in effect. Also, the minimum bactericidal concentration (MBC) was four times the minimum inhibitory concentration (MIC). The highest MIC was related to zinc oxide nanoparticles and the lowest was related to the simultaneous use of essential oil and nanoparticles. In the combined mode of treatments, half the MIC of separate treatments was required. Also, with the reduction of the effect m.

The results indicated that clinical strains were highly resistant to some antibiotics but sensitive to others. Also, Khuzestan savory essential oil and zinc oxide nanoparticles were effective against standard strains and clinical isolates. The main component of this essential oil was carvacrol, which has antimicrobial properties. The results showed that the combination of essential oil and nanoparticles led to a stronger and more effective reduction in lasR gene expression. The study concluded that the combination of Khuzestan savory essential oil and zinc oxide nanoparticles is a promising complementary and alternative therapeutic approach for the treatment of chronic Pseudomonas aeruginosa infections.