Antibacterial activity of Thymus vulgaris essential oil alone and in combination with cefotaxime against blaESBL producing multidrug resistant Enterobacteriaceae isolates

Chemical composition of five essential oils and their antioxidant and in vitro and in vivo antifungal activities against Alternaria alternata in tomato crop

This study aimed to determine the chemical composition of essential oils from A. gratíssima, O. basilicum, S. microphylla, T. riparia, and T. vulgaris and their antioxidant and antifungal activities against Alternaria alternata strains. Gas chromatography-mass spectrometry revealed that the major components of the essential oils were terpenes. The essential oils of S. microphylla and T. riparia showed higher antioxidant activities than the others. The essential oils of S. microphylla and T. riparia inhibited the growth of the fungus at 3.10 and 6.05 µL/mL, respectively. The essential oil of T. riparia inhibited 93.9% of the growth of the fungus and showed the highest in vivo efficiency in severity reduction (76.2%). We conclude that the essential oil of T. riparia shows promising antifungal activity and is an environmentally safe alternative for controlling fungal diseases in vegetables.

The Phytochemical Tactics for Battling Antibiotic Resistance in Microbes: Secondary Metabolites and Nano Antibiotics Methods

One of the most serious threats to human health is antibiotic resistance, which has left the world without effective antibiotics. While continuous research and inventions for new antibiotics are going on, especially those with new modes of action, it is unlikely that this alone would be sufficient to win the battle. Furthermore, it is also important to investigate additional approaches. One such strategy for improving the efficacy of existing antibiotics is the discovery of adjuvants. This review has collected data from various studies on the current crisis and approaches for combating multi-drug resistance in microbial pathogens using phytochemicals. In addition, the nano antibiotic approaches, are discussed, highlighting the high potentials of essential oils, alkaloids, phenolic compounds, and nano antibiotics in combating antibiotic resistance.

Antibacterial and Antibiofilm Efficacy of Thyme (Thymus vulgaris L.) Essential Oil against Foodborne Illness Pathogens, Salmonella enterica subsp. enterica Serovar Typhimurium and Bacillus cereus

Nowadays, the wide spread of foodborne illness and the growing concerns about the use of synthetic food additives have shifted the focus of researchers towards essential oils (EOs) as possible antimicrobials and preservatives of natural origin. Thanks to their antimicrobial properties against pathogenic and food spoilage microorganisms, EOs have shown good potential for use as alternative food additives, also to counteract biofilm-forming bacterial strains, the spread of which is considered to be among the main causes of the increase in foodborne illness outbreaks. In this context, the aim of this study has been to define the antibacterial and antibiofilm profile of thyme (Thymus vulgaris L.) essential oil (TEO) against widespread foodborne pathogens, Salmonella enterica subsp. enterica serovar Typhimurium and Bacillus cereus. TEO chemical composition was analyzed through gas chromatography-mass spectrometry (GC-MS). Preliminary in vitro antibacterial tests allowed to qualitatively verify TEO efficacy against the tested foodborne pathogens. The subsequent determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values allowed to quantitatively define the bacteriostatic and bactericidal effects of TEO. To evaluate the ability of essential oils to inhibit biofilm formation, a microplate assay was performed for the bacterial biofilm biomass measurement. Results suggest that TEO, rich in bioactive compounds, is able to inhibit the growth of tested foodborne bacteria. In addition, the highlighted in vitro anti-biofilm properties of TEO suggest the use of this natural agent as a promising food preservative to counteract biofilm-related infections in the food industry.

Herbal Products and Their Active Constituents Used Alone and in Combination with Antibiotics against Multidrug-Resistant Bacteria

The purpose of this review is to summarize the current knowledge acquired on herbal products and their active constituents with antimicrobial activity used alone and in combination with antibiotics against multidrug-resistant bacteria. The most promising herbal products and active constituents used alone against multidrug-resistant bacteria are Piper betle (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, extended-spectrum beta-lactamase, Acinetobacter baumannii, Pseudomonas aeruginosa), Glycyrrhiza glabra (methicillin-resistant S. aureus, vancomycin-resistant Enterococcus, P. aeruginosa), and berberine (methicillin-resistant S. aureus, A. baumannii, P. aeruginosa), respectively. The synergistic effect of the combination of herbal products and their active constituents with antibiotics against multidrug-resistant bacteria are also described. These natural antibacterial agents can be promising sources of inhibitors, which can modulate antibiotic activity against multidrug-resistant bacteria, especially as efflux pump inhibitors. Other possible mechanisms of action of herbal therapy against multidrug-resistant bacteria including modification of the bacterial cell wall and/or membrane, inhibition of the cell division protein filamenting temperature sensitive Z-ring, and inhibition of protein synthesis and gene expression, all of which will also be discussed. Our review suggests that combination herbal therapy and antibiotics can be effectively used to expand the spectrum of their antimicrobial action. Therefore, combination therapy against multidrug-resistant bacteria may enable new choices for the treatment of infectious diseases and represents a potential area for future research.

Marine bioactive compounds as antibiofilm agent: a metabolomic approach

The ocean is a treasure trove of both living and nonliving creatures, harboring incredibly diverse group of organisms. A plethora of marine sourced bioactive compounds are discovered over the past few decades, many of which are found to show antibiofilm activity. These are of immense clinical significance since the formation of microbial biofilm is associated with the development of high antibiotic resistance. Biofilms are also responsible to bring about problems associated with industries. In fact, the toilets and wash-basins also show degradation due to development of biofilm on their surfaces. Antimicrobial resistance exhibited by the biofilm can be a potent threat not only for the health care unit along with industries and daily utilities. Various recent studies have shown that the marine members of various kingdom are capable of producing antibiofilm compounds. Many such compounds are with unique structural features and metabolomics approaches are essential to study such large sets of metabolites. Associating holobiome metabolomics with analysis of their chemical attribute may bring new insights on their antibiofilm effect and their applicability as a substitute for conventional antibiotics. The application of computer-aided drug design/discovery (CADD) techniques including neural network approaches and structured-based virtual screening, ligand-based virtual screening in combination with experimental validation techniques may help in the identification of these molecules and evaluation of their drug like properties.

Immune Defences: A View from the Side of the Essential Oils

The use of essential oils is increasingly being investigated among new therapeutic approaches based on medicinal plants and their extracts. With the wide use of synthetic and semi-synthetic antimicrobial drugs, the spread of drug-resistant clinical isolates has increased, and research is directed towards natural products, such as essential oils, as useful antimicrobial resources. In the context of a prospective infection, we compared the impact of essential oils and common antimicrobial agents on the microbicidal activity of human phagocytes. Here, we present the results of our decades-long investigation into the effectiveness of thyme red oil (26.52% thymol chemotype), tea tree oil (TTO), and Mentha of Pancalieri [(Mentha x piperita (Huds) var. officinalis (Sole), form rubescens (Camus) (Lamiaceae)] essential oils on human polymorphonuclear leukocytes (PMNs) capacity to kill clinical strains of Candida albicans and C. krusei when compared to three antifungal drugs used to treat candidiasis (fluconazole, anidulafungin, and caspofungin) These essential oils demonstrate antifungal drug-like and/or superior efficacy in enhancing intracellular killing by PMNs, even at subinhibitory concentrations. Our results are compared with data in the literature on essential oils and immune system interactions. This comparison would aid in identifying therapeutic solutions to the increasingly prevalent antibiotic resistance as well as filling in any remaining knowledge gaps on the bioactivity of essential oils.

Comparative Evaluation of a Commercial Herbal Extract and 0.2% Chlorhexidine Mouthwash on Three Periodontal Facultative Anaerobes: An In Vitro Study

Background

The application of herbal and/or chemical antimicrobial mouthwashes in addition to the mechanical methods of bacteria removal helps reduce the periopathogens and thus increase the periodontal tissues' health. The present study aimed to evaluate the antibacterial effect of Thymex (TMX) syrup on three periodontal facultative anaerobes in vitro and compare it with 0.2% chlorhexidine (CHX) mouthwash.

Methods

In this in vitro experiment, the disc diffusion method was used to measure the inhibitory halo diameter (IhD) of Enterobacter cloacae, Actinomyces viscosus, and Eikenella corrodens. The paper discs containing TMX and CHX were placed on Mueller-Hinton agar media and cultured with the mentioned bacteria. Moreover, a blank disc containing distilled water was used as a control. From each of the three bacterial species, five samples were taken, and after 18 hours of storage in the incubator, the IhDs were measured in millimeters. A one-way ANOVA test and an independent sample t-test were used to compare the mean differences of IhDs between groups. The significance level was considered to be 0.05.

Results

The IhDs ranged between 6.2-8.8 mm and 12.3-34 mm for TMX and CHX, respectively. CHX showed a more inhibitory effect on all three species of bacteria compared to TMX mouthwash (P < 0.001).

Conclusions

Despite the inhibitory effect of TMX on bacterial growth, CHX showed significantly more antibacterial activity than TMX against three studied bacterial species.

Towards Green Strategies of Food Security: Antibacterial Synergy of Essential Oils from Thymus vulgaris and Syzygium aromaticum to Inhibit Escherichia coli and Staphylococcus aureus Pathogenic Food Isolates

Foodborne diseases continue to represent an important public health issue. The control of food spoilage and pathogenic microorganisms is achieved mainly by synthetic chemicals, unfortunately associated to several undesirable aspects. The growing requirement for new and safe alternative strategies has resulted in the research of agents from natural sources with antimicrobial properties, such as essential oils (EOs). This study's purpose was to define the antibacterial profile of thyme (Thymus vulgaris) and cloves (Syzygium aromaticum) essential oils against both Gram-positive and Gram-negative important foodborne pathogenic bacteria. Gas chromatography mass spectrometry analysis was performed for EOs' chemical composition. Qualitative in vitro antimicrobial assays (i.e., agar well diffusion method and disk-volatilization method) allowed for verification of the efficacy of EOs, used individually and in binary combination and both in liquid and vapor phase, against Staphylococcus aureus and Escherichia coli food isolates. Minimal inhibitory concentrations and minimal bactericidal concentration values have been used to quantitatively measure the antibacterial activity of EOs, while the fractional inhibitory concentration index has been considered as a predictor of in vitro antibacterial synergistic effects. The microbiological tests suggest that thyme and cloves EOs, rich in bioactive compounds, are able to inhibit the growth of tested foodborne bacteria, especially in vapor phase, also with synergistic effects. Results provide evidence to consider the tested essential oils as promising sources for development of new, broad-spectrum, green food preservatives.

Effects of Alcohol Consumption on Oxidative Stress in a Sample of Patients Recruited in a Dietary Center in a Southern University Hospital: A Retrospective Study

Background and objectives: The aim of this retrospective study was to evaluate the effects of alcohol consumption on oxidative stress. Materials and Methods: The study was conducted by analyzing the increase in lipid peroxidation, the reduction of antioxidant defenses and the alteration of the oxidation/antioxidant balance after the administration of ethanol in 25% aqueous solution (v/v) at a concentration of 0.76 g/kg of body weight daily in two doses for 3 days. The changes in oxidative stress indices were investigated by standard methods previously described. Results: Ethanol administration has determined a significant increase in plasma levels of lipid hydroperoxide (LOOH), malonilaldehyde (MDA) and oxidized glutathione (GSSH), and a decrease in total antioxidant capacity (TAC), reduced glutathione (GSH) and GSH/GSSH ratio. Conclusions: In the proposed experimental condition, the excessive and repeated consumption of ethanol causes oxidative damage, as shown by the increase in lipid peroxidation, the reduction of antioxidant defenses and the alteration of the oxidation/antioxidant balance, which, at least in part, are responsible for the harmful effects of excess ethanol.

Effect of Thymus vulgaris L. essential oil and thymol on the microbiological properties of meat and meat products: A review

Since foodborne diseases are often considered as one of the biggest public health threats worldwide, effective preservation strategies are needed to inhibit the growth of undesirable microorganisms in food commodities. Up to now, several techniques have been adopted for the production of safe and high-quality products. Although the traditional methods can improve the reliability, safety, and shelf-life of food, some of them cannot be applied without rising health concerns. Thereby, the addition of various phytochemicals has gained much attention during the last decades, especially for meat products that may be contaminated with pathogenic and spoilage organisms.

Thyme (Thymus vulgaris L.), as an important medicinal and culinary herb, is a promising source of bioactive compounds that have a great impact on the microbiological stability of meat by suppressing the undesirable microflora. However, the use of these antimicrobials is still facing difficulties due to their aromatic properties and variable efficacy against targeted species.

In this paper, we provide an overview on the potential effects of thyme essential oil (EO) and thymol as bio-preservative agents in meat products. Furthermore, this paper provides insights into the limitations and current challenges of the addition of EOs and their constituents to meat commodities and suggests viable solutions that can improve the applicability of these phytochemicals.

In-Depth Study of Thymus vulgaris Essential Oil: Towards Understanding the Antibacterial Target Mechanism and Toxicological and Pharmacological Aspects

Questions have been raised apropos the emerging problem of microbial resistance, which may pose a great hazard to the human health. Among biosafe compounds are essential oils which captured consumer draw due to their multifunctional properties compared to chemical medication drugs. Here, we examined the chemical profile and the mechanism(s) of action of the Thymus vulgaris essential oil (TVEO) against a Gram-negative bacterium Salmonella enterica Typhimurium ATTCC 10028 (S. enterica Typhimurium ATTCC 10028) and two Gram-positive bacteria Staphyloccocus aureus ATCC 6538 (S. aureus ATCC 6538) and Listeria monocytogenes ATCC 19117 (L. monocytogenes ATCC 19117). Findings showed that TVEO was principally composed of thymol, o-cymene, and γ-terpinene with 47.44, 16.55, and 7.80%, respectively. Molecular docking simulations stipulated that thymol and β-sesquiphellandrene (a minor compound at 1.37%) could target multiple bacterial pathways including topoisomerase II and DNA and RNA polymerases of the three tested bacteria. This result pointed plausible impairments of the pathogenic bacteria cell replication and transcription processes. Through computational approach, the VEGA quantitative structure–activity relationship (QSAR) model, we revealed that among twenty-six TVEO compounds, sixteen had no toxic effects and could be safe for human consumption as compared to the Food and Drug Administration (FDA) approved drugs (ciprofloxacin and rifamycin SV). Assessed by the SwissADME server, the pharmacokinetic profile of all identified TVEO compounds define their absorption, distribution, metabolism, and excretion (ADME) properties and were assessed. In order to predict their biological activity spectrum based on their chemical structure, all TVEO compounds were subjected to PASS (Prediction of Activity Spectra for Substances) online tool. Results indicated that the tested compounds could have multiple biological activities and various enzymatic targets. Findings of our study support that identified compounds of TVEO can be a safe and effective alternative to synthetic drugs and can easily combats hazardous multidrug-resistant bacteria.

Current State of Knowledge Regarding WHO Critical Priority Pathogens: Mechanisms of Resistance and Proposed Solutions through Candidates Such as Essential Oils

The rise of multidrug-resistant (MDR) pathogens has become a global health threat and an economic burden in providing adequate and effective treatment for many infections. This large-scale concern has emerged mainly due to mishandling of antibiotics (ABs) and has resulted in the rapid expansion of antimicrobial resistance (AMR). Nowadays, there is an urgent need for more potent, non-toxic and effective antimicrobial agents against MDR strains. In this regard, clinicians, pharmacists, microbiologists and the entire scientific community are encouraged to find alternative solutions in treating infectious diseases cause by these strains. In its "10 global issues to track in 2021", the World Health Organization (WHO) has made fighting drug resistance a priority. It has also issued a list of bacteria that are in urgent need for new ABs. Despite all available resources, researchers are unable to keep the pace of finding novel ABs in the face of emerging MDR strains. Traditional methods are increasingly becoming ineffective, so new approaches need to be considered. In this regard, the general tendency of turning towards natural alternatives has reinforced the interest in essential oils (EOs) as potent antimicrobial agents. Our present article aims to first review the main pathogens classified by WHO as critical in terms of current AMR. The next objective is to summarize the most important and up-to-date aspects of resistance mechanisms to classical antibiotic therapy and to compare them with the latest findings regarding the efficacy of alternative essential oil therapy.

Effect of Essential Oils Supplemented with Caprylic Acid and Sodium Chloride against Faecal ESBL-Producing Escherichia coli Isolated from Pigs

The purpose of the present investigation was to compare the antibacterial activity of six commercial and lab-scale extracted essential oils (EOs) alone or in combination with caprylic acid (CA) and sodium chloride (NaCl) against faecal Escherichia coli with and without extended-spectrum beta-lactamase (ESBL) encoding genes, and of isolates classified as multidrug-resistant (MDR). Gas chromatography−mass spectrometry (GC−MS) was used for the analysis of chemical composition of EOs, while the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were carried out to elucidate the antibacterial activity of non-supplemented and supplemented EOs against different resistance levels of E. coli strains. The main compounds in commercial EOs were aromatic monoterpenoids (30−56%) and p-cymene (8−35%), while the main compounds in the lab-scale EOs were aromatic monoterpenoids (12−37%) and γ-terpinene (18−22%). Commercial EOs exhibited superior inhibitory activity of E. coli in comparison to lab-scale produced EOs. Antibacterial activity of EOs was significantly enhanced by enrichment of the EOs with NaCl (p < 0.001) or CA (p = 0.012). Most of the non-supplemented EOs exhibited lower activity against MDR and ESBL producing E. coli. In contrast, EOs supplemented with CA and especially NaCl was equally effective against ESBL and non-ESBL as well as MDR and non-MDR E. coli. It was found that supplementation of EOs with NaCl could enhance the antibacterial activity towards ESBL and MDR E. coli isolates. However, additional studies are needed to clarify the potential risks of developing resistance.

Exploring Phytochemicals for Combating Antibiotic Resistance in Microbial Pathogens

Antibiotic resistance or microbial drug resistance is emerging as a serious threat to human healthcare globally, and the multidrug-resistant (MDR) strains are imposing major hurdles to the progression of drug discovery programs. Newer antibiotic-resistance mechanisms in microbes contribute to the inefficacy of the existing drugs along with the prolonged illness and escalating expenditures. The injudicious usage of the conventional and commonly available antibiotics in human health, hygiene, veterinary and agricultural practices is proving to be a major driver for evolution, persistence and spread of antibiotic-resistance at a frightening rate. The drying pipeline of new and potent antibiotics is adding to the severity. Therefore, novel and effective new drugs and innovative therapies to treat MDR infections are urgently needed. Apart from the different natural and synthetic drugs being tested, plant secondary metabolites or phytochemicals are proving efficient in combating the drug-resistant strains. Various phytochemicals from classes including alkaloids, phenols, coumarins, terpenes have been successfully demonstrated their inhibitory potential against the drug-resistant pathogens. Several phytochemicals have proved effective against the molecular determinants responsible for attaining the drug resistance in pathogens like membrane proteins, biofilms, efflux pumps and bacterial cell communications. However, translational success rate needs to be improved, but the trends are encouraging. This review highlights current knowledge and developments associated challenges and future prospects for the successful application of phytochemicals in combating antibiotic resistance and the resistant microbial pathogens.

An overview of research of essential oils by self-organizing maps: A novel approach for meta-analysis study

Essential oils (EOs) are commercially important products, sources of compounds with antioxidant and antimicrobial activities considered indispensable for several fields, such as the food industry, cosmetics, perfumes, pharmaceuticals, sanitary and agricultural industries. In this context, this systematic review and meta-analysis, a novel approach will be presented using chemometric tools to verify and recognize patterns of antioxidant, antibacterial, and antifungal activities of EOs according to their geographic, botanical, chemical, and microbiological distribution. Scientific papers were selected following the Preferred Reporting Items for Systematic Review and Meta-Analyses statement flow diagram, and the data were evaluated by the self-organizing map and hierarchical cluster analysis. Overall, this novel approach allowed us to draw an overview of antioxidants and antimicrobials activities of EOs reported in 2019, through 585 articles evaluated, obtaining a dataset with more than 10,000 data, distributed in more than 80 countries, 290 plant genera, 150 chemical compounds, 30 genera of bacteria, and 10 genera of fungi. The networks for geographic, botanical, chemical, and microbiological distribution indicated that Brazil, Asia, the botanical genus Thymus, species Thymus vulgaris L. "thyme," the Lamiaceae family, limonene, and the oxygenated monoterpene class were the most representative in the dataset, while the species Escherichia coli and Candida albicans were the most used to assess the antimicrobial activity of EOs. This work can be seen as a guide for the processing of metadata using a novel approach with non-conventional statistical methods. However, this preliminary approach with EOs can be extended to other sources or areas of food science.

Comparison of sensitivity to a commercial Origanum vulgare essential oil between extended-spectrum β-lactamases (ESBL-) and non-ESBL-producing Enterobacteriaceae isolates

This study aimed to evaluate the antibacterial effect of Origanum vulgare essential oil (OVEO) against ESBL- and non-ESBL-producing multidrug-resistant (MDR) Enterobacteriaceae isolates. OVEO composition was determined using Gas chromatograph-mass spectrometer (GC/MS). In the current study, the effect of OVEO was studied on seven MDR Enterobacteriaceae isolates. Antibacterial activity of OVEO was investigated by the disc diffusion assay and twofold serial dilution method. GC/MS analysis identified thymol (78.21%) as the single major component present in the OVEO. This EO showed an unexpectedly high antibacterial activity against all the studied MDR Enterobacteriaceae isolates, with inhibition zone diameters and minimum inhibitory concentration (MIC) values ranging from 28 ± 0.6 to 35 ± 0.6 mm and 0.31 ± 0.0 to 5 ± 0.0 μL/mL, respectively. However, ESBL-producing isolates were more susceptible to OVEO than non-ESBL producing isolates. This study compared, for the first time, the sensitivity to OVEO between ESBL and non-ESBL-producing Enterobacteriaceae isolates.

Molecular Characterization of KPC-2-Producing Enterobacter cloacae Complex Isolates from Cali, Colombia

The Enterobacter cloacae complex is an emerging opportunistic pathogen whose increased resistance to carbapenems is considered a public health problem. This is due to the loss of efficacy of beta-lactam antibiotics, which are used as the first treatment option in the management of infections caused by Gram-negative bacteria. The objective of this study was to perform the molecular characterization of 28 isolates of the E. cloacae complex resistant to cephalosporins and carbapenems isolated between 2011 and 2018 from five hospitals located in the municipality of Santiago de Cali, Colombia. Molecular detection of bla_KPC, bla_VIM, bla_NDM and bla_OXA-48-like genes was performed on these isolates and the genetic relationship between the isolates was assessed using multilocus sequence typing (MLST). Forty-three percent of the isolates carried the bla_KPC-2 gene variant. MLST showed high genetic diversity among isolates, the most frequent being the sequence type ST510 with a frequency of 50%. The identification of the genes involved in carbapenem resistance and dispersing genotypes is an important step toward the development of effective prevention and epidemiological surveillance strategies in Colombian hospitals.

A systematic review on ethnopharmacology, phytochemistry and pharmacological aspects of Thymus vulgaris Linn

Thymus vulgaris Linn. is a medicinal and culinary herb from the Southern European region known for its anti-infective, cardioprotective, gastroprotective, anti-inflammatory, and immunomodulatory activities since the Egyptian era. The reported pharmacological activities of T. vulgaris L. include antibacterial, antioxidant, anti-inflammatory, antiviral, and anti-cancerous activities. In this review, a comprehensive approach is put forth to scrutinize and report the available data on phytochemistry, ethnopharmacology, pharmacology, and toxicology of the plant. The different extracts and essential oil obtained from the plant have been assessed and reported to treat ailments like microbial infections, inflammation, non-communicable diseases like cancer, and sexually transmitted diseases like HIV-1 and Herpes. The literature review has also indicated the use of volatile oils, phenolic acids, terpenoids, flavonoids, saponins, steroids, tannins, alkaloids, and polysaccharides in pharmacotherapy. Applications of these compounds including antidiabetic, anti-Alzheimer's, cardio, neuro and hepatoprotective, anti-osteoporosis, sedative, immunomodulatory, antioxidant, anti-tyrosinase, antispasmodic, antinociceptive, gastroprotective, anticonvulsant, antihypertensive, antidepressant, anti-amnesia, and anti-helminthic activities have been mentioned. Further, based on research gaps, recommendations have been provided to evaluate T. vulgaris L. systematically to develop plant-based drugs, nutraceuticals, and to evaluate their clinical efficiency and safety.

Rapid Screening of Essential Oils as Substances Which Enhance Antibiotic Activity Using a Modified Well Diffusion Method

Antimicrobial resistance is recognized as one of the major global health challenges of the 21st century. Synergistic combinations for antimicrobial therapies can be a good strategy for the treatment of multidrug resistant infections. We examined the ability of a group of 29 plant essential oils as substances which enhance the antibiotic activity. We used a modified well diffusion method to establish a high-throughput screening method for easy and rapid identification of high-level enhancement combinations against bacteria. We found that 25 essential oils possessed antibacterial activity against Escherichia Coli ATCC 25922 and methicillin-resistant Staphylococcus aureus (MRSA) 43300 with MICs that ranged from 0.01% to 2.5% v/v. We examined 319 (11 × 29) combinations in a checkerboard assay with E. Coli ATCC 25922 and MRSA 43300, and the result showed that high-level enhancement combinations were 48 and 44, low-level enhancement combinations were 214 and 211, and no effects combinations were 57 and 64, respectively. For further verification we randomly chose six combinations that included orange and Petitgrain essential oils in a standard time-killing assay. The results are in great agreement with those of the well diffusion assays. Therefore, the modified diffusion method was a rapid and effective method to screen high-level enhancement combinations of antibiotics and essential oils.

Essential Oils: A Natural Weapon against Antibiotic-Resistant Bacteria Responsible for Nosocomial Infections

The emergence of antibiotic-resistant bacteria has become a major concern worldwide. This trend indicates the need for alternative agents to antibiotics, such as natural compounds of plant origin. Using agar disc diffusion and minimum inhibitory concentration (MIC) assays, we investigated the antimicrobial activity of Citrus aurantium (AEO), Citrus x limon (LEO), Eucalyptus globulus (EEO), Melaleuca alternifolia (TTO), and Cupressus sempervirens (CEO) essential oils (EOs) against three representatives of antibiotic-resistant pathogens and respective biofilms: vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Using the checkerboard method, the efficacy of the EOs alone, in an association with each other, or in combination with the reference antibiotics was quantified by calculating fractional inhibitory concentrations (FICs). All the EOs displayed antibacterial activity against all strains to different extents, and TTO was the most effective. The results of the EO–EO associations and EO–antibiotic combinations clearly showed a synergistic outcome in most tests. Lastly, the effectiveness of EOs both alone and in association or combination against biofilm formed by the antibiotic-resistant strains was comparable to, and sometimes better than, that of the reference antibiotics. In conclusion, the combination of EOs and antibiotics represents a promising therapeutic strategy against antibiotic-resistant bacteria, even protected inside biofilms, which can allow decreasing the concentrations of antibiotics used.

Thymol nanoemulsion promoted broiler chicken's growth, gastrointestinal barrier and bacterial community and conferred protection against Salmonella Typhimurium

The present study involved in vivo evaluation of the growth promoting effects of thymol and thymol nanoemulsion and their protection against Salmonella Typhimurium infection in broilers. One-day old 2400 chicks were randomly divided into eight groups; negative and positive control groups fed basal diet without additives and thymol and thymol nanoemulsion groups (0.25, 0.5 and 1% each). At d 23, all chicks except negative control were challenged with S. Typhimurium. Over the total growing period, birds fed 1% thymol nanoemulsion showed better growth performance even after S. Typhimurium challenge, which came parallel with upregulation of digestive enzyme genes (AMY2A, PNLIP and CCK). Additionally, higher levels of thymol nanoemulsion upregulated the expression of MUC-2, FABP2, IL-10, IgA and tight junction proteins genes and downregulated IL-2 and IL-6 genes expression. Moreover, 1% thymol nanoemulsion, and to lesser extent 0.5% thymol nanoemulsion and 1% thymol, corrected the histological alterations of cecum and liver postinfection. Finally, supplementation of 1% thymol, 0.5 and 1% thymol nanoemulsion led to increased Lactobacilli counts and decreased S. Typhimurium populations and downregulated invA gene expression postinfection. This first report of supplying thymol nanoemulsion in broiler diets proved that 1% nano-thymol is a potential growth promoting and antibacterial agent.

Evaluation of Antibacterial Activity of Essential Oils and Their Combination against Multidrug-Resistant Bacteria Isolated from Skin Ulcer

Background

Emerging of multidrug-resistant bacteria can compromise the effectiveness of antibiotics used to treat skin infections. Those bacteria imposed public health problems and questioning medical care in the 21^st century. In this circumstance, essential oils of medicinal plants origin are supreme sources of structural and functionally divergent compounds, which inhibited the growth of common wound colonizing MRSA and ESBL producing P. aeruginosa. The aim of this study was to evaluate the combined antibacterial activity of essential oils extracted from Rumex abyssinicus, Cucumis pustulatus, and Discopodium penninervium against multidrug-resistant (MDR) isolates of skin ulcers.

Methods

Essential oils (EOs) were extracted from aerial parts of R. abyssinicus, C. pustulatus, and D. penninervium with steam distillation. A mixture of each oil (1 : 1) was adsorbed to a disc and placed on Mueller Hinton Agar. Then, minimum zone of inhibition and bactericidal concentration of EOs was measured after incubeted for 18–24 hours at 37 °C. Their combined antibacterial effect was determined by the fractional inhibitory concentration index.

Results

The antibacterial activity of mixed oil varied in their doses and bacteria species, of which a mixture of essential oil of R. abyssinicus and D. penninervium had inhibition zone (32 mm); its MIC and MBC values range from 1-2 μl/ml against MRSA. It had an inhibition zone (36 mm), MIC value 4 μl/ml, and MBC (8 μl/ml) against ESBL producing P. aeruginosa, whereas combined effects of R. abyssinicus and C. pustulatus had MIC values ranging from 2–8 μl/ml for E. coli and K. pneumoniae and 2 μl/ml for MRSA. There was a strong synergistic effect between R. abyssinicus and D. penninervium and promising antibacterial effect more specifically on MRSA and P. aeruginosa. Conclusion. This in vitro study of the combined effect of EOs has significant antibacterial activity on wound colonizing bacteria and reduces delaying wound healing as that of modern drugs tested in parallel. Hence, further structural elucidation of active compounds helps us to properly design or synthesis of topical antibiotics for wound care.

Antioxidant, Antimicrobial and Antiviral Properties of Herbal Materials

Recently, increasing public concern about hygiene has been driving many studies to investigate antimicrobial and antiviral agents. However, the use of any antimicrobial agents must be limited due to their possible toxic or harmful effects. In recent years, due to previous antibiotics' lesser side effects, the use of herbal materials instead of synthetic or chemical drugs is increasing. Herbal materials are found in medicines. Herbs can be used in the form of plant extracts or as their active components. Furthermore, most of the world's populations used herbal materials due to their strong antimicrobial properties and primary healthcare benefits. For example, herbs are an excellent material to replace nanosilver as an antibiotic and antiviral agent. The use of nanosilver involves an ROS-mediated mechanism that might lead to oxidative stress-related cancer, cytotoxicity, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound healing. Therefore, existing antibiotic drugs can be replaced with biomaterials such as herbal medicine with high antimicrobial, antiviral, and antioxidant activity. This review paper highlights the antibacterial, antiviral, and radical scavenger (antioxidant) properties of herbal materials. Antimicrobial activity, radical scavenger ability, the potential for antimicrobial, antiviral, and anticancer agents, and efficacy in eliminating bacteria and viruses and scavenging free radicals in herbal materials are discussed in this review. The presented herbal antimicrobial agents in this review include clove, portulaca, tribulus, eryngium, cinnamon, turmeric, ginger, thyme, pennyroyal, mint, fennel, chamomile, burdock, eucalyptus, primrose, lemon balm, mallow, and garlic, which are all summarized.

Antibacterial activity and mechanism of three isomeric terpineols of Cinnamomum longepaniculatum leaf oil

α-Terpineol, terpinen-4-ol, and δ-terpineol, isomers of terpineol, are among the compounds that give Cinnamomum longepaniculatum leaf oil its distinguished pleasant smell. The objective of this study was to evaluate the antimicrobial activity of these three isomeric terpineols. The determination of antibacterial activity was based on the minimum inhibition concentration (MIC) and minimum bactericide concentration (MBC). Changes in time-kill curve, alkaline phosphatase (AKP), UV-absorbing material, membrane potential, and scanning electron microscopy (SEM) were measured to elucidate the possible antimicrobial mechanism. α-Terpineol, terpinen-4-ol, and δ-terpineol demonstrated good inhibitory effects against several gram-negative bacteria, particularly Shigella flexneri. MIC and MBC of α-terpineol and terpinen-4-ol were similar (0.766 mg/mL and 1.531 mg/mL, respectively) for S. flexneri, while the MIC and MBC values of δ-terpineol were 0.780 mg/mL and 3.125 mg/mL, respectively. Time-kill curves showed that the antibacterial activities of the tested compounds were in a concentration-dependent manner. Release of nucleic acids and proteins along with a decrease in membrane potential proved that α-terpineol, terpinen-4-ol, and δ-terpineol could increase the membrane permeability of Shigella flexneri. Additionally, the release of AKP suggested that the cell wall was destroyed. SEM analysis further confirmed that S. flexneri cell membranes were damaged by α-terpineol, terpinen-4-ol, and δ-terpineol. Our research suggests that these three isomeric terpineols have the potential of being used as natural antibacterial agents by destroying the cell membrane and wall, resulting in cell death. However, the specific antibacterial activity differences need further investigation.

Restoration of the Antibiotic Susceptibility of Methicillin-Resistant Staphylococcus aureus and Extended-Spectrum β-Lactamases Escherichia coli Through Combination with Chelerythrine

Multidrug resistance poses a severe threat to public health and urgently requires new solutions. The natural product chelerythrine (CHE) is a benzophenanthridine alkaloid with antimicrobial potential. In this study, CHE was effective against seven gram-positive bacterial strains, and the minimum inhibitory concentrations (MICs) ranged from 2 to 4 μg/mL. By contrast, CHE showed inferior antibacterial activities against 11 gram-negative strains, and the MICs varied from 16 to 256 μg/mL. We also determined the synergistic/additive effects of combining CHE with nine currently used antibiotics. CHE restored the antibacterial efficacy of the antibiotics against methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamases producing Escherichia coli. This study suggests that the combination of CHE with conventional antibiotics may be a promising strategy to combat infections caused by multidrug-resistant organisms.

The Variability of Thymol and Carvacrol Contents Reveals the Level of Antibacterial Activity of the Essential Oils from Different Accessions of Oliveria decumbens

Oliveria decumbens (Apiaceae) is an aromatic herb traditionally employed in the Persian medicine for the treatment of infectious and gastrointestinal disorders. In the present study, we analyzed the chemical composition of essential oils obtained from different Iranian populations and evaluated their efficacy on a panel of human pathogens (Staphylococcus aureus and Escherichia coli), probiotic (Bacillus subtilis), and phytopathogens (Clavibacter michiganensis, Curtobacterium flaccumfaciens, Xanthomonas citri, and Agrobacterium tumefaciens). The gas chromatographic-mass spectrometry analysis put in evidence four main volatile constituents such as thymol (20.3–36.4%), carvacrol (18.8–33.1%), γ-terpinene (10.6–25.9%), and p-cymene (9.5–17.3%), though with significant variability from an essential oil to another. Notably, the oils from the populations sited in Nourabad Mamasani and Dehdasht showed the highest amount of the phenolic monoterpenes thymol (36.4 and 35.2%, respectively) and carvacrol (33.1 and 30.6%, respectively). The antibacterial activity of O. decumbens essential oils was assessed by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods, showing high activity for the samples from Nourabad Mamasani and Dehdasht populations exhibiting high level of the above phenolics. The obtained MIC and MBC values (mg/ml) were in the ranges 0.0625–2 mg/ml and 1–16 mg/ml, respectively. Noteworthy, in some cases, the antibacterial activity of O. decumbens essential oils was higher than that of chloramphenicol used as positive control. The average MBCs displayed by the O. decumbens samples showed that C. flaccumfaciens had the highest sensitivity to the essential oils. Based on these results, our work shed light on selected O. decumbens populations deserving proper breeding and cultivation strategies in order to warrantee production of bioactive essential oils to be used at pharmaceutical and agricultural level to combat several pathogens.

Bioactive Natural Compounds and Antioxidant Activity of Essential Oils from Spice Plants: New Findings and Potential Applications

Spice plants have a great influence on world history. For centuries, different civilizations have used them to condiment the foods of kings and nobles and applied them as embalming preservatives, perfumes, cosmetics, and medicines in different regions of the world. In general, these plants have formed the basis of traditional medicine and some of their derived substances have been utilized to treat different human diseases. Essential oils (EOs) obtained from these plants have been also used as therapeutic agents and have shown supportive uses in remedial practices. The discovery and development of bioactive compounds from these natural products, based on their traditional uses, play an important role in developing the scientific evidence of their potential pharmaceutical, cosmetic, and food applications. In the present review, using recent studies, we exhibit a general overview of the main aspects related to the importance of spice plants widely used in traditional medicine: Cinnamomum zeylanicum (true cinnamon), Mentha piperita (peppermint), Ocimum basilicum (basil), Origanum vulgare (oregano), Piper nigrum (black pepper), Rosmarinus officinalis (rosemary), and Thymus vulgaris (thyme); and we discuss new findings of the bioactive compounds obtained from their EOs, their potential applications, as well as their molecular mechanisms of action, focusing on their antioxidant activity. We also exhibit the main in vitro methods applied to determine the antioxidant activities of these natural products.

In Vitro Activity of Essential Oils Against Planktonic and Biofilm Cells of Extended-Spectrum β-Lactamase (ESBL)/Carbapenamase-Producing Gram-Negative Bacteria Involved in Human Nosocomial Infections

The aim of this study was to analyze the antibacterial activity of four essential oils (EOs), Melaleuca alternifolia, Eucalyptus globulus, Mentha piperita, and Thymus vulgaris, in preventing the development and spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa and carbapenemase (KPC)-producing Klebsiella pneumoniae. A total of 60 strains were obtained from the stock collection from the Microbiology Laboratory of Hesperia Hospital, Modena, Italy. Twenty ESBL-producing E. coli, 5 K. pneumoniae, 13 KPC-producing K. pneumoniae, and 20 MBL-producing P. aeruginosa were cultured and reconfirmed as ESBL and carbapenamase producers. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (ESBL and KPC/MBL). Antibacterial activity of the EOs was determined using the agar disk diffusion assay, and minimal inhibitory concentrations (MICs) were also evaluated. Lastly, adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 24 randomly selected strains. M. alternifolia and T. vulgaris EOs showed the best antibacterial activity against all tested strains and, as revealed by agar disk diffusion assay, M. alternifolia was the most effective, even at low concentrations. This effect was also confirmed by MICs, with values ranging from 0.5 to 16 µg/mL and from 1 to 16 µg/mL, for M. alternifolia and T. vulgaris EOs, respectively. The EOs' antibacterial activity compared to antibiotics confirmed M. alternifolia EO as the best antibacterial agent. T. vulgaris EO also showed a good antibacterial activity with MICs lower than both reference antibiotics. Lastly, a significant anti-biofilm activity was observed for the two EOs (*P < 0.05 and **P < 0.01 for M. alternifolia and T. vulgaris EOs, respectively). A good antibacterial and anti-biofilm activity of M. alternifolia and T. vulgaris EOs against all selected strains was observed, thus demonstrating a future possible use of these EOs to treat infections caused by ESBL/carbapenemase-producing strains, even in association with antibiotics.

Sucupira Oil-Loaded Nanostructured Lipid Carriers (NLC): Lipid Screening, Factorial Design, Release Profile, and Cytotoxicity

Essential oils are odorant liquid oily products consisting of a complex mixture of volatile compounds obtained from a plant raw material. They have been increasingly proven to act as potential natural agents in the treatment of several human conditions, including diabetes mellitus (DM). DM is a metabolic disorder characterized by chronic hyperglycemia closely related to carbohydrate, protein and fat metabolism disturbances. In order to explore novel approaches for the management of DM our group proposes the encapsulation of sucupira essential oil, obtained from the fruits of the Brazilian plants of the genus Pterodon, in nanostructured lipid carriers (NLCs), a second generation of lipid nanoparticles which act as new controlled drug delivery system (DDS). Encapsulation was performed by hot high-pressure homogenization (HPH) technique and the samples were then analyzed by dynamic light scattering (DLS) for mean average size and polydispersity index (PI) and by electrophoretic light scattering (ELS) for zeta potential (ZP), immediately after production and after 24 h of storage at 4 °C. An optimal sucupira-loaded NLC was found to consist of 0.5% (m/V) sucupira oil, 4.5% (m/V) of Kollivax^® GMS II and 1.425% (m/V) of TPGS (formulation no. 6) characterized by a mean particle size ranging from 148.1 ± 0.9815 nm (0 h) to 159.3 ± 9.539 nm (at 24 h), a PI from 0.274 ± 0.029 (0 h) to 0.305 ± 0.028 (24 h) and a ZP from −0.00236 ± 0.147 mV (at 0 h) to 0.125 ± 0.162 (at 24 h). The encapsulation efficiency and loading capacity were 99.98% and 9.6%, respectively. The optimized formulation followed a modified release profile fitting the first order kinetics, over a period of 8 h. In vitro cytotoxicity studies were performed against Caco-2 cell lines, for which the cell viability above 90% confirmed the non-cytotoxic profile of both blank and sucupira oil-loaded NLC.

Resistance to multiple first-line antibiotics among Escherichia coli from poultry in Western Algeria

BACKGROUND AND AIM

Escherichia coli can cause a number of serious infections both in human and veterinary medicine. Their management is increasingly complicated by the emergence and dissemination of multiresistance to various first-line antimicrobial agents. This study aimed to evaluate the resistance level to the commonly used antibiotics, with a focus on the first-line antimicrobial agents, in E. coli strains isolated from poultry in Western Algeria.

MATERIALS AND METHODS

E. coli culture was done on MacConkey agar and their identification was determined by AP20E system. For susceptibility testing, disk diffusion method to 14 antimicrobials, including first-line antibiotics, was used according to Kirby-Bauer disk diffusion method in Mueller-Hinton agar and the results were interpreted according to the Clinical and Laboratory Standards Institute guidelines. E. coli isolates were considered as multidrug resistance (MDR) when found resistant to at least one antimicrobial agent of three different families of antibiotics. Double-disk synergy and combination disk tests were used for initial screening and confirmation for extended-spectrum β-lactamases (ESBLs) production, respectively.

RESULTS

A total of 145 E. coli strains were isolated in this study. High resistance levels to various antibiotics, including commonly used first-line antimicrobial agents, were recorded in this study. The highest resistance level was observed against nalidixic acid (90.34%, n=131), followed by tetracycline (86.89%, n=126), ampicillin (82.75%, n=120), enrofloxacin (80.68%, n=117) and neomycin (80.68%, n=117), trimethoprim/sulfamethoxazole (73.79%, n=107), norfloxacin (72.41%, n=105) and cephalothin (72.41%, n=105), amoxicillin/clavulanic acid (51.72%, n=75), chloramphenicol (22.75%, n=33), nitrofurantoin (17.24%, n=25), gentamicin (13.10%, n=19), and ceftiofur (3.44%, n=5). Moreover, resistance to multiple first-line antibiotics was also demonstrated in the present study. Overall, 139 out of 145 isolates (95.86%) demonstrated MDR (resistant to at least three antibiotics). In addition, five E. coli isolates (3.44%) were confirmed to be ESBL producers.

CONCLUSION

The alarming rate of E. coli resistant to multiple first-line antibiotics in poultry demands intensified surveillance. These results call for taking drastic measures to preserve antibiotic effectiveness and reduce the emergence risks of extensively drug-resistant and pandrug-resistant E. coli isolates.

Considerations and Caveats in Combating ESKAPE Pathogens against Nosocomial Infections

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are among the most common opportunistic pathogens in nosocomial infections. ESKAPE pathogens distinguish themselves from normal ones by developing a high level of antibiotic resistance that involves multiple mechanisms. Contemporary therapeutic strategies which are potential options in combating ESKAPE bacteria need further investigation. Herein, a broad overview of the antimicrobial research on ESKAPE pathogens over the past five years is provided with prospective clinical applications.

Synergistic Combinations of Antibiotics with Cumin, Oregano and Rosewood Oils as a Strategy to Preserve the Antibiotic Repertoire

Background:

Formulations employing synergistic combinations of antibiotics with Essential Oils (EOs) could help preserve the antibiotic repertoire by improving their activity against resistant bacteria.

Objective:

Antimicrobial interactions between double and triple combinations of EOs, EO components and antibiotics were determined using the checkerboard method. The most active triple combinations were then assessed by a time-kill assay.

Methods:

Two synergistic EO-antibiotic combinations and eight additive EO-antibiotic combinations reduced the antibiotic minimum inhibitory concentration below clinical sensitivity breakpoints according to the checkerboard method. However, all the tested combinations were additive according to the time-kill assay; while the combinations completely killed S. aureus, E. coli and P. aeruginosa cells in 2 h. At least one EO compound from the combination alone completely killed the cells of test species.

Results:

Two synergistic EO-antibiotic combinations and eight additive EO-antibiotic combinations reduced the antibiotic minimum inhibitory concentration below clinical sensitivity breakpoints according to the checkerboard method. However, all the tested combinations were additive according to the time-kill assay; while the combinations completely killed S. aureus, E. coli and P. aeruginosa cells in 2 h. At least one EO compound from the combination alone completely killed the cells of test species.

Conclusion:

Positive interactions support the use of EOs or EO components to enhance antibiotic efficacy against antibiotic resistant bacteria. The EO-antibiotic combinations tested by the time kill assay were indifferent; therefore, the observed antimicrobial activity did not arise from synergistic mechanisms as indicated by the checkerboard method. Investigation of other synergistic combinations identified by the checkerboard method could reveal more promising candidates.

Phytochemical study, an evaluation of the antioxidant potential and the antimicrobial activity of Inga semialata (Vell.) C. Mart. hydroalcohol extract

Inga semialata (Vell.) C. Mart. belongs to the family Fabaceae. It is known for its therapeutic properties, highlighting its antimicrobial and antioxidant potential. The objective of the present work was to obtain crude extract leaves of Inga semialata, to identify and quantify active compounds, to evaluate the antioxidant potential of the crude extract in vitro, as well as to determine its antimicrobial activity. The crude extract was obtained by the maceration process. The identified and quantified of compounds present in the crude extract of Inga semialata was performed by high performance liquid chromatography. The evaluation of the antioxidant potential of the extract was realized by in vitro tests (DPPH, diacetate dichlorofluorescein test and nitric oxide test) and the evaluation of the antimicrobial activity was carried out using the minimum inhibitory concentration methodology.

Inula viscosa (L.) Aiton leaves and flower buds: Effect of extraction solvent/technique on their antioxidant ability, antimicrobial properties and phenolic profile

This study was designed to establish the most effective solvent/technique for extracting antioxidant phytoconstituents from leaves and flower buds of Inula viscosa (L.) Aiton (Asteraceae) grown wild in Morocco. Maceration and hot extraction with methanol or water and Soxhlet ethanol extraction were utilized. The antioxidant potential was evaluated in vitro by DPPH, reducing power, and ferrous ions chelating activity assays. I. viscosa leaf and flower bud extracts displayed the strongest effect in the DPPH test, being the Soxhlet ethanol the most active ones (IC₅₀ = 54.24 ± 0.21 μg/mL and 39.77 ± 0.23 μg/mL); thus, they were selected for further investigations. The antimicrobial efficacy of the Soxhlet ethanol extracts against ATCC and food isolates strains was assayed; the leaf extract showed the best activity, and Candida albicans was the most sensitive strain (MIC = 125 µg/mL). The extracts resulted non-toxic against Artemia salina. Among the phenolics characterised by HPLC-PDA-ESI-MS, hispidulin hexoside, patuletin and spinacetin were identified for the first time.

Chemical Composition and Antibacterial Activity of Essential Oils from Ferula L. Species against Methicillin-Resistant Staphylococcus aureus

Essential oils (EOs) were obtained by hydrodistillation of various parts of Ferula ovina (Boiss.) Boiss., Ferula iliensis Krasn. ex. Korovin, and Ferula akitschkensis B. Fedtsch. ex Koso-Pol., collected in the flowering/budding and fruiting stages. Eight samples of EOs isolated from F. ovina and four samples from F. akitsckensis were analyzed by gas chromatography⁻mass spectrometry (GC-MS). The major constituents of F. ovina EOs were α-pinene (6.9⁻47.8%), β-pinene (1.5⁻7.1%), sabinene (0.1⁻20.5%), β-phellandrene (0⁻6.5%), trans-verbenol (0.9⁻7.4%), eremophilene (3.1⁻12%), and 6Z-2,5,5,10-tetramethyl-undeca-2,6,9-trien-8-one (0⁻13.7%). The major constituents of F. akitsckensis EOs were α-pinene (0⁻46.2%), β-pinene (0⁻47.9%), sabinene (0⁻28.3%), eremophilene (0⁻10.6), β-caryophyllene (0⁻7.5%), himachalen-7-ol (0⁻28.2%), and an himachalol derivative (0⁻8.3%). Samples of EOs from F. ovina, F. iliensis, and F. akitsckensis were evaluated for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) pulse-field gel electrophoresis type USA300 (LAC). EOs from F. ovina exhibited the highest antibacterial activity compared to samples from other Ferula spp., with the most potent EOs being isolated from roots at the flowering and fruiting stages and stems at the fruiting stage (IC₅₀ values of 19.1, 20.9, and 22.9 µg/mL, respectively). Although EOs demonstrated concentration-dependent inhibition of MRSA growth, analysis of the major constituents (α-pinene, β-pinene, and sabinene) showed that they had low activity, suggesting that other components were likely responsible for the observed bioactivity of the unfractionated EOs. Indeed, correlation of the GC-MS data with antibacterial activity suggested that the putative components responsible for antibacterial activity were, either individually or in combination, eremophilene and trans-verbenol. Overall, these results suggest that the EOs from F. ovina could have potential for use as alternative remedies for the treatment of infectious diseases caused by MRSA.