The antimicrobial activity of Lavandula angustifolia Mill. essential oil against Staphylococcus species in a hospital environment

Staphylococcus haemolyticus: An updated review on nosocomial infections, antimicrobial resistance, virulence, genetic traits, and strategies for combating this emerging opportunistic pathogen

Staphylococcus haemolyticus, a key species of the Staphylococcus genus, holds significant importance in healthcare-associated infections, due to its notable resistance to antimicrobials, like methicillin, and proficient biofilms-forming capabilities. This coagulase-negative bacterium poses a substantial challenge in the battle against nosocomial infections. Recent research has shed light on Staph. haemolyticus genomic plasticity, unveiling genetic elements responsible for antibiotic resistance and their widespread dissemination within the genus. This review presents an updated and comprehensive overview of the clinical significance and prevalence of Staph. haemolyticus, underscores its zoonotic potential and relevance in the one health framework, explores crucial virulence factors, and examines genetics features contributing to its success in causing emergent and challenging infections. Additionally, we scrutinize ongoing studies aimed at controlling spread and alternative approaches for combating it.

Antibacterial Activity Assessment of Chitosan/Alginate Lavender Essential Oil Membranes for Biomedical Applications

The demand for natural products in the treatment of dermatological pathologies has boosted the use of bioactive substances such as lavender essential oil (LEO), which stands out for its anti-inflammatory and antioxidant properties and its antimicrobial potential. Biopolymers such as chitosan (CHT) and alginate (ALG) are biodegradable and biocompatible and have proven their viability in biomedical applications such as skin regeneration. The inhibitory effect of LEO on the growth of skin-related bacterial species Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and the fungus Candida albicans was studied by incorporating 1% v/v LEO encapsulated in CHT, ALG, and CHT/ALG membranes. Despite the verification of the antimicrobial effect of all type of membranes, no synergistic effect was observed following the addition of LEO. S. aureus and P. aeruginosa showed the most growth on the different substrates and C. albicans demonstrated the highest inhibition. This is a first approach using microorganisms isolated from clinical samples or skin microbiota. Further investigation would be advisable using more clinical strains for each microorganism to validate their biomedical applicability.

Chemical Composition and Biological Properties of New Romanian Lavandula Species

The aims of the present study were to evaluate for the first time the chemical composition and antioxidant, antibacterial, antifungal and antiproliferative potentials of the Romanian George 90 lavender species, as well as parental species, L. angustifolia and L. latifolia. The L. angustifolia, L. latifolia and George 90 essential oils were analyzed by GC-MS/MS and the L. angustifolia, L. latifolia and George 90 hydroalcoholic extracts were analyzed by HPLC-DAD. The antioxidant, antibacterial, antifungal and antiproliferative assays revealed that all the investigated species showed significant activities. The results highlighted the chemical composition and the promising biological potentials of the L. angustifolia, L. latifolia and George 90 lavender species, validating their ethnomedicinal value, which offers potential applications as natural drugs.

Lavandula Species, Their Bioactive Phytochemicals, and Their Biosynthetic Regulation

Lavandula species are one of the most useful aromatic and medicinal plants and have great economic potential. The phytopharmaceutical contribution of the secondary metabolites of the species is unquestionable. Most recent studies have been focusing on the elucidation of the genetic background of secondary metabolite production in lavender species. Therefore, knowledge of not only genetic but especially epigenetic mechanisms for the regulation of secondary metabolites is necessary for the modification of those biosynthesis processes and the understanding of genotypic differences in the content and compositional variability of these products. The review discusses the genetic diversity of Lavandula species in relation to the geographic area, occurrence, and morphogenetic factors. The role of microRNAs in secondary-metabolites biosynthesis is described.

Natural Compounds with Antimicrobial Properties in Cosmetics

Currently, the cosmetic industry is a very intensively growing part of the economy. Consumer demands are adapted to the current lifestyle, which is based on technological innovations and awareness of the impact of various factors on human health and fitness. There is growing interest in cosmetics based on environmentally friendly natural compounds exerting health-promoting effects. Chemicals with antimicrobial properties used as ingredients in cosmetics ensure their durability and safety. Polyphenolic compounds, peptides, essential oils, and plant extracts characterized by these properties are natural ingredients that can replace synthetic components of cosmetics. The advantage of these compounds is that they exhibit antioxidant, anti-inflammatory, and soothing properties, enhancing the product value in addition to their antimicrobial properties. This review article describes the antimicrobial properties of natural compounds that can protect cosmetics and can replace previously used preservative agents. Various studies indicate that the use of these compounds increases consumer interest in these products and has a positive impact on the environment.

Citrus sinensis Essential Oils an Innovative Antioxidant and Antipathogenic Dual Strategy in Food Preservation against Spoliage Bacteria

The present study evaluates the chemical compositions and antioxidant and antipathogenic properties of commercial orange (Citrus sinensis (L.) Osbeck) essential oils obtained using the cold-press method (EOP) and the cold-press method followed by steam distillation (EOPD). The chemical compositions of the volatilizable fractions, determined by gas chromatography-mass spectrometry, were similar in both samples. A relatively large amount of γ-terpinene was found in the EOPD (1.75%) as compared to the EOP (0.84%). Monoterpene hydrocarbons with limonene (90.4-89.8%) followed by myrcene (3.2-3.1%) as the main compounds comprised the principal phytochemical group. The non-volatile phenolics were eight times higher in the EOP than in the EOPD. Several assays with different specificity levels were used to study the antioxidant activity. Although both essential oils presented similar reducing capacities, the radical elimination ability was higher for the EOP. Regarding the antipathogenic properties, the EOs inhibited the biomass and cell viability of Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Furthermore, both EOs similarly attenuated the production of elastase, pyocyanin, and quorum-sensing autoinducers as assessed using Gram-negative bacteria. The EOP and EOPD showed important antioxidant and antipathogenic properties, so they could represent natural alternatives to extend the shelf life of food products by preventing oxidation and contamination caused by microbial spoilage.

DNA extraction leads to bias in bacterial quantification by qPCR

Quantitative PCR (qPCR) has become a widely used technique for bacterial quantification. The affordability, ease of experimental design, reproducibility, and robustness of qPCR experiments contribute to its success. The establishment of guidelines for minimum information for publication of qPCR experiments, now more than 10 years ago, aimed to mitigate the publication of contradictory data. Unfortunately, there are still a significant number of recent research articles that do not consider the main pitfalls of qPCR for quantification of biological samples, which undoubtedly leads to biased experimental conclusions. qPCR experiments have two main issues that need to be properly tackled: those related to the extraction and purification of genomic DNA and those related to the thermal amplification process. This mini-review provides an updated literature survey that critically analyzes the following key aspects of bacterial quantification by qPCR: (i) the normalization of qPCR results by using exogenous controls, (ii) the construction of adequate calibration curves, and (iii) the determination of qPCR reaction efficiency. It is primarily focused on original papers published last year, where qPCR was applied to quantify bacterial species in different types of biological samples, including multi-species biofilms, human fluids, and water and soil samples. KEY POINTS: • qPCR is a widely used technique used for absolute bacterial quantification. • Recently published papers lack proper qPCR methodologies. • Not including proper qPCR controls significantly affect experimental conclusions.

Beyond the Bark: An Overview of the Chemistry and Biological Activities of Selected Bark Essential Oils

Essential oils have been used by indigenous peoples for medicinal purposes since ancient times. Their easy availability played an important role. Even today, essential oils are used in various fields—be it as aromatic substances in the food industry, as an aid in antibiotic therapy, in aromatherapy, in various household products or in cosmetics. The benefits they bring to the body and health are proven by many sources. Due to their complex composition, they offer properties that will be used more and more in the future. Synergistic effects of various components in an essential oil are also part of the reason for their effectiveness. Infectious diseases will always recur, so it is important to find active ingredients for different therapies or new research approaches. Essential oils extracted from the bark of trees have not been researched as extensively as from other plant components. Therefore, this review will focus on bringing together previous research on selected bark oils to provide an overview of barks that are economically, medicinally, and ethnopharmaceutically relevant. The bark oils described are Cinnamomum verum, Cedrelopsis grevei, Drypetes gossweileri, Cryptocarya massoy, Vanillosmopsis arborea and Cedrus deodara. Literature from various databases, such as Scifinder, Scopus, Google Scholar, and PubMed, among others, were used.

Synergy based extracts of medicinal plants: Future antimicrobials to combat multidrug resistance

The use of herbal medicines and supplements in the last thirty years has increased enormously. Herbal medication has demonstrated promising and effective potential against various diseases. Herbal and phytoconstituent medications are gaining popularity globally and many people are adopting herbal remedies to deal with different health issues. The indiscriminate use of antibiotics, due to the development of antimicrobial resistance, poses an unprecedented problem for human civilization. Bacterial infections are difficult to cure because of the propensity of microbes to acquire resistance to a wide range of antimicrobial drugs. New compounds are being explored and quantified for possible antibacterial activity with little or no side effects. Researchers are investigating the range of therapeutic plants mentioned in Unani, Ayurveda, and Siddha around the globe. Known and commonly acclaimed global databases such as PubMed, Research Gate, Science Direct, Google Scholar, were searched using different search strings such as Indian medicinal plants, multidrug resistance (MDR), thin layer chromatography (TLC), antimicrobials, and Synergism were used in diverse combinations to reclaim numerous citations associated with this area. Thus, the current review aims to shed a light on the information of medicinal plants as a potential foundation of herbal drugs and elucidate how synergism and TLC bioautography plays a crucial role in finding antimicrobial compounds.

Control of Airborne Microorganisms by Essential Oils Released by VaxiPod

Currently, due to the global pandemic caused by severe acute respiratory syndrome coronavirus SARS-CoV-2, new procedures and devices for effective disinfection of indoor air are of obvious interest. Various studies demonstrated quite broad ranges of the efficiency of essential oils in the control of biological aerosols. This project reports the results of investigation of the antimicrobial activity of essential oils natural for Australia (tea tree oil, eucalyptus oil and lemon myrtle) distributed by newly developed VaxiPod device for various scenarios, including bacterial, viral and fungal inactivation on various surfaces and in aerosol form. It was found that the device was capable of operating continuously over 24-h periods, providing sufficient aerosol concentration to efficiently inactivate microorganisms both on the surface and in airborne form. Twenty-four to forty-eight hours were required to achieve inactivation above 90% of most of the tested microbes on solid surfaces (stainless steel discs and agar plates), whilst similar efficiency of inactivation on fibrous filter surface as well as in aerosol form was achieved over 30–60 min of the process run. The results look very promising for further development of bioaerosol inactivating procedures and technologies for air quality control applications.