Flow Cytometry and Liquid Broth Microdilution Assay Evaluation of the Synergistic Activity of Eugenol with Current Antibiotics Against Eskape Clinical Strains

*Haifaa Najee
Department Of Biology, AL- Muthanna University, College Of Science, Al-Muthanna University, Iraq, Iraq

*Corresponding Author:
Haifaa Najee
Department Of Biology, AL- Muthanna University, College Of Science, Al-Muthanna University, Iraq, Iraq

Published on: 2020-03-30


Considering the increase in antibiotic-resistant (AR) bacterial strains and the lack of new antibiotics, alternative/complementary strategies need to be founded to solve the infections due to AR pathogens. A possible solution may be to combine existing antibiotics with phytochemicals to enhance their efficacy. The purpose of this study was to assess the synergy between eugenol and a set of antibiotics currently used for the treatment of infections produced by Gram positive and Gram negative strains.


Antibiotic-resistant bacterial strains, Antibiotics, Gram-negative bacteria, Gram-positive bacteria


The antibiotics resistance problem in microbial strains is presumed as a method for continuity [1,2]. lately, the rapid growth of resistant strains is occurring worldwide, endangering the potency of antibiotics, which have transformed medicine and saved millions of lives [1]. P. aeruginosa is one of the most common bacteria isolated from chronic wounds is an opportunistic pathogen with innate resistance to several classes of antibiotics because of the low permeability of its outer membrane, the essential expression of various efflux pumps, and the production of antibiotic-inactivating enzymes (e.g., cephalosporinases) [3]. Methicillin-resistant S. aureus (MRSA) is a common problem in hospital settings and in the community. The most common cause of hospital-acquired infections is represented by hospital-acquired MRSA (HA-MRSA), and CA-MRSA (MRSA acquired in the community) [4,5].

There is a continuous and urgent need to discover new antimicrobial compounds with diverse chemical structures and novel mechanisms of action because there has been a threatening increase in the incidence of new and re-emerging infectious diseases. Another big problem is the development of antibiotics resistance in current clinical use. Higher plants produce hundreds to thousands of diverse chemical compounds with different biological activities. The antimicrobial compounds produced by plants are active against pathogenic microorganisms. It is expected that plant extracts showing target sites other than those used by antibiotics will be active against drug-resistant microbial pathogens [6].

Thus, herbal treatment would promise a greater viable solution for the effective treatment of diseases caused by bacteria [7,8]. In vitro and in vivo studies have revealed that essential oils mixtures, oleoresin, flavonoids, alkaloids, phenol, and phenolic compounds, tannin, xanthone and xanthone derivatives, diterpene acid, phenylpropanoid glycosides, acteoside, and the bisnaphthquione derivatives have antimicrobial and anti-inflammatory activities [9]. The World Health Organization (WHO) estimates that 80 % of the world’s population presently uses herbal medicine for some aspect of primary health care. Our aims for this study are: To assess the anti-pathogenic activity of the extracts from commercial oils and to search and propose a mechanism of action for the tested extracts.

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