# Evaluation of the antibacterial effects of four essential oils on antibiotic-resistant bacteria isolated from ventilator-dependent patients

## TL;DR

This study tests essential oils from four plants against antibiotic-resistant bacteria in ventilator-dependent patients, finding promising antibacterial effects.

## Contribution

This is the first study to report the antibacterial effects of these four essential oils against bacteria from ventilator-dependent patients.

## Key findings

- Trachyspermum ammi produced the largest inhibition zones against all tested bacteria.
- Oliveria decumbens showed stronger antibacterial effects at lower concentrations compared to Trachyspermum ammi.
- Both Trachyspermum ammi and Oliveria decumbens show potential as antibacterial agents against drug-resistant bacteria.

## Abstract

Antibacterial resistance has become a critical global health concern. In recent years, significant efforts have been made to discover and utilize natural plant-based products as alternative antibacterial agents. This study aims to evaluate the antibacterial effects of essential oils from four medicinal plants against drug-resistant bacteria isolated from tracheal cultures of ventilator-dependent patients.

Essential oils were extracted from Oliveria
decumbens, Zataria
multiflora, Cuminum
cyminum, and Trachyspermum
ammi using a Clevenger apparatus. The antibacterial efficacy was tested against drug-resistant bacterial strains, including four strains of Escherichia (E.) coli, five strains of Klebsiella (K.) pneumoniae, and four strains of Pseudomonas (P.) aeruginosa, all isolated from the sputum of ventilator-dependent patients. The disk diffusion method was used to assess antibacterial activity, and the minimum inhibitory concentration (MIC) method was employed to evaluate the antibacterial properties of the two most effective essential oils.

The antibiogram results demonstrated that Trachyspermum ammi produced the largest inhibition zones against all bacteria, followed by Oliveria decumbens. Trachyspermum ammi showed the highest antibacterial activity against E. coli, while Oliveria decumbens was most effective against K. pneumoniae. In MIC testing, Oliveria decumbens exhibited a stronger antibacterial effect at lower concentrations compared to Trachyspermum ammi.

This study is the first to report the antibacterial effects of the essential oils from all four plants, particularly Trachyspermum ammi and Oliveria decumbens, against bacteria isolated from ventilator-dependent patients. Both plants show promising potential as antibacterial agents against these drug-resistant bacteria.