Antioxidant Activity and Effectiveness of Fig Extract in Counteracting Carbon Tetrachloride-Induced Oxidative Damage in Rats.

Figs are the edible fruits of the fig tree, Ficus carica L., that have been used for centuries for human consumption and in traditional medicine, to treat skin problems, inflammation, and gastrointestinal disorders. Our previous study investigated the presence of phenolic compounds in aqueous extracts of two Algerian popular fig varieties, azendjar (Az) and taamriouth (Ta), as well as their in vitro antioxidant activity. In this study, we assessed hydroethanolic extracts of these fig varieties. The total phenolic content was measured, along with the phenolic profile. Rutin was determined to be the dominant phenolic compound, followed by vanillic acid, 3,4-dihydroxybenzoic acid, quercetin, 4-hydroxybenzoic acid, rosmarinic acid (in Az only), and cinnamic acid. The antioxidant activity of the extracts was evaluated both in vitro (DPPH and FRAP assays) and in vivo, in rats intoxicated with carbon tetrachloride. In all assays, the fig extract-especially the dark-peeled fig variety azendjar-showed antioxidant potency. The administration of fig extract resulted in a reduction in liver damage, expressed by both different biochemical markers and histopathological study (less degraded liver architecture, reduced fibrosis, and only mild inflammation). A dose-dependent therapeutic effect was observed. The extract from the dark-peeled fig variety, Az, was characterized by a higher phenolic content and a stronger antioxidant activity than the extract from the light-peeled variety-Ta. Our study justifies the use of figs in traditional healing and shows the potential of using fig extracts in natural medicines and functional foods.

A Tiny Flexible Differential Tension Sensor.

Modern applications of Internet of Things (IoT) devices require cheap and effective methods of measurement of physical quantities. Cheap IoT devices with sensor functionalities can detect a lack or excess of substances in everyday life or industry processes. One possible use of tension sensors in IoT applications is the automated replenishment process of fast moving consumer goods (FMCG) on shop shelves or home retail automation that allows for quick ordering of FMCG, where the IoT system is a part of smart packaging. For those reasons, a growing demand for cheap and tiny tension sensors has arisen. In this article, we propose a solution of a small flexible tension sensor fabricated in an amorphous InGaZnO (a-IGZO) thin-film process that can be integrated with other devices, e.g., near-field communications (NFC) or a barcode radio frequency identification (RFID) tag. The sensor was designed to magnify the slight internal changes in material properties caused by mechanical stress. These changes affect the dynamic electrical properties of specially designed inverters for a pair of ring oscillators, in which the frequencies become stress-dependent. In the article, we discuss and explain the approach to the optimum design of a ring oscillator that manifests the highest sensitivity to mechanical stress.

Lavandula × intermedia-A Bastard Lavender or a Plant of Many Values? Part I. Biology and Chemical Composition of Lavandin.

This review article is the first in a series that provides an overview of the biology, chemistry, biological effects, and applications of Lavandula × intermedia (lavandin, LI). Despite its prevalence in cultivation and on the essential oil market, lavandin has received limited attention from the scientific community. Remarkably more attention is paid to Lavandula angustifolia (LA), which is commonly regarded as the superior lavender and has been extensively researched. Our goal is to provide a comprehensive review of LI, as none currently exists, and assess whether its inferior status is merited. In the first part, we outline the biological and chemical characteristics of the plant and compare it to the parent species. The chemical composition of lavandin oil is similar to that of LA but contains more terpenes, giving camphor notes that are less valued in perfumery. Nevertheless, lavandin has some advantages, including a higher essential oil yield, resulting in reduced production cost, and therefore, it is a preferred lavender crop for cultivation.

Lavandula x intermedia-A Bastard Lavender or a Plant of Many Values? Part II. Biological Activities and Applications of Lavandin.

This review article is the second in a series aimed at providing an in-depth overview of Lavandula x intermedia (lavandin). In part I, the biology and chemistry of lavandin were addressed. In part II, the focus is on the functional properties of lavandin and its applications in industry and daily life. While reviewing the biological properties, only original research articles employing lavandin were considered. Lavandin essential oil has been found to have antioxidant and biocidal activity (antimicrobial, nematicidal, antiprotozoal, insecticidal, and allelopathic), as well as other potential therapeutic effects such as anxiolytic, neuroprotective, improving sleep quality, antithrombotic, anti-inflammatory, and analgesic. Other lavandin preparations have been investigated to a much lesser extent. The research is either limited or inconsistent across all studies, and further evidence is needed to support these properties. Unlike its parent species-Lavandula angustifolia (LA)-lavandin essential oil is not officially recognized as a medicinal raw material in European Pharmacopeia. However, whenever compared to LA in shared studies, it has shown similar effects (or even more pronounced in the case of biocidal activities). This suggests that lavandin has similar potential for use in medicine.

Mentha piperita: Essential Oil and Extracts, Their Biological Activities, and Perspectives on the Development of New Medicinal and Cosmetic Products.

This review aims to analyze Mentha piperita L. as a potential raw material for the development of new health-promoting products (nutraceuticals, cosmetics, and pharmaceutical products). A lot of scientific publications were retrieved from the Scopus, PubMed, and Google Scholar databases which enable the study and generalization of the extraction procedures, key biologically active compounds of essential oil and extracts, biological properties, and therapeutic potential of M. piperita, along with perspectives on the development of its dosage forms, including combinations of synthetic active substances and herbal preparations of M. piperita. The results of this review indicate that M. piperita is a source rich in phytoconstituents of different chemical nature and can be regarded as a source of active substances to enhance health and to develop medicinal products for complementary therapy of various conditions, especially those related with oxidant stress, inflammation, and moderate infections. Essential oil has a broad spectrum of activities. Depending on the test and concentration, this essential oil has both anti- and prooxidant properties. Gram-positive bacteria are more sensitive to the essential oil of M. piperita than Gram-negative ones. This review also considered some facets of the standardization of essential oil and extracts of M. piperita. Among the identified phenolics of extracts were caffeic acid, rosmarinic acid, eriocitrin, luteolin derivates (luteolin-7-O-rutinoside, luteolin-7-O-glucoronide), and hesperidin. The concentration of these phenolics depends on the solvent used. This review also considered the relationships between the chemical component and biological activity. The results showed that the essential oil and extracts reduced inflammation in vitro by inhibiting the production of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and in vivo by reducing the paw edema induced using carrageenan injection in rats. Therefore, herbal preparations of M. piperita are promising medicinal and cosmetic preparations for their usage in skincare and oral cavity care products with antimicrobial, anti-inflammatory, and wound-healing properties. This plant can also be regarded as a platform for the development of antibacterial preparations and combined anti-inflammatory and cardioprotective medicinal products (synthetic active substances plus herbal preparations). This review could be considered for the justification of the composition of some medicinal products during their pharmaceutical development for writing a registration dossier in the format of Common Technical Document.

Chemical Variability and Pharmacological Potential of Propolis as a Source for the Development of New Pharmaceutical Products.

This review aims to analyze propolis as a potential raw material for the development and manufacture of new health-promoting products. Many scientific publications were retrieved from the Scopus, PubMed, and Google Scholar databases via searching the word "propolis". The different extraction procedures, key biologically active compounds, biological properties, and therapeutic potential of propolis were analyzed. It was concluded that propolis possesses a variety of biological properties because of a very complex chemical composition that mainly depends on the plant species visited by bees and species of bees. Numerous studies found versatile pharmacological activities of propolis: antimicrobial, antifungal, antiviral, antioxidant, anticancer, anti-inflammatory, immunomodulatory, etc. In this review, the composition and biological activities of propolis are presented from a point of view of the origin and standardization of propolis for the purpose of the development of new pharmaceutical products on its base. It was revealed that some types of propolis, especially European propolis, contain flavonoids and phenolic acids, which could be markers for the standardization and quality evaluation of propolis and its preparations. One more focus of this paper was the overview of microorganisms' sensitivity to propolis for further development of antimicrobial and antioxidant products for the treatment of various infectious diseases with an emphasis on the illnesses of the oral cavity. It was established that the antimicrobial activity of different types of propolis is quite significant, especially to Gram-negative bacteria and lipophilic viruses. The present study could be also of interest to the pharmaceutical industry as a review for the appropriate design of standardized propolis preparations such as mouthwashes, toothpastes, oral drops, sprays, creams, ointments, suppositories, tablets, and capsules, etc. Moreover, propolis could be regarded as a source for the isolation of biologically active substances. Furthermore, this review can facilitate partially overcoming the problem of the standardization of propolis preparations, which is a principal obstacle to the broader use of propolis in the pharmaceutical industry. Finally, this study could be of interest in the area of the food industry for the development of nutritionally well-balanced products. The results of this review indicate that propolis deserves to be better studied for its promising therapeutic effects from the point of view of the connection of its chemical composition with the locality of its collection, vegetation, appropriate extraction methods, and standardization.

Comparative Evaluation of the Essential Oil of the New Ukrainian Lavandula angustifolia and Lavandula x intermedia Cultivars Grown on the Same Plots.

New cultivars of lavender adapted to arid steppe conditions were developed by the Institute of Rice of Ukrainian National Academy of Agrarian Sciences (NAAS). This work is a part of the characterization process of the new cultivars. The chemical composition of the essential oil of the seven new Lavandula angustifolia and eight new Lavandula x intermedia cultivars was investigated and compared. In total, 71 different compounds were identified. Linalool and linalool acetate were the main components in both species in ranges of 26.14-57.07% and 9.08-24.45%, respectively. They were followed by terpinen-4-ol (2.16-22.44%), lavandulyl acetate (2.12-10.23%), and lavandulol (1.30-3.14) in the case of L. angustifolia and camphor (10.11-12.55%), borneol (5.49-8.71%), and eucalyptol (0.47-7.41%) in the case of L. x intermedia. The oils had a valuable terpene profile-a high linalool content and the substantial presence of lavandulol and its ester. Nevertheless, they did not comply with the industry standards, mostly due to high levels of terpinene-4-ol. Evidently, a high content of terpinen-4-ol is a characteristic feature of L. angustifolia oils bred in Ukraine. Additionally, the LA3 cultivar yielded an oil with some of the highest linalool contents reported in the literature. Statistical analysis and literature data allowed for the comparative analysis of the gathered data. MANOVA, PCA, and HCA marked caryophyllene oxide as another potential differentiating compound between studied species.

Expression of AraC/XylS stress response regulators in two distinct carbapenem-resistant Enterobacter cloacae ST89 biotypes.

BACKGROUND: The growing incidence of MDR Gram-negative bacteria is a rapidly emerging challenge in modern medicine. OBJECTIVES: We sought to establish the role of intrinsic drug-resistance regulators in combination with specific genetic mutations in 11 Enterobacter cloacae isolates obtained from a single patient within a 7 week period. METHODS: The molecular characterization of eight carbapenem-resistant and three carbapenem-susceptible E. cloacae ST89 isolates included expression-level analysis and WGS. Quantitative PCR included: (i) chromosomal cephalosporinase gene (ampC); (ii) membrane permeability factor genes, e.g. ompF, ompC, acrA, acrB and tolC; and (iii) intrinsic regulatory genes, e.g. ramA, ampR, rob, marA and soxS, which confer reductions in antibiotic susceptibility. RESULTS: In this study we describe the influence of the alterations in membrane permeability (ompF and ompC levels), intrinsic regulatory genes (ramA, marA, soxS) and intrinsic chromosomal cephalosporinase AmpC on reductions in carbapenem susceptibility of E. cloacae clinical isolates. Interestingly, only the first isolate possessed the acquired VIM-4 carbapenemase, which has been lost in subsequent isolates. The remaining XDR E. cloacae ST89 isolates presented complex carbapenem-resistance pathways, which included perturbations in permeability of bacterial membranes mediated by overexpression of ramA, encoding an AraC/XylS global regulator. Moreover, susceptible isolates differed significantly from other isolates in terms of marA down-regulation and soxS up-regulation. CONCLUSIONS: Molecular mechanisms of resistance among carbapenem-resistant E. cloacae included production of acquired VIM-4 carbapenemase, significant alterations in membrane permeability due to increased expression of ramA, encoding an AraC/XylS global regulator, and the overproduction of chromosomal AmpC cephalosporinase.

What is the form of muscimol from fly agaric mushroom (Amanita muscaria) in water? An insight from NMR experiment supported by molecular modeling.

The biologically active alkaloid muscimol is present in fly agaric mushroom (Amanita muscaria), and its structure and action is related to human neurotransmitter γ -aminobutyric acid (GABA). The current study reports on determination of muscimol form present in water solution using multinuclear 1 H and 13 C nuclear magnetic resonance (NMR) experiments supported by density functional theory molecular modeling. The structures of three forms of free muscimol molecule both in the gas phase and in the presence of water solvent, modeled by polarized continuous model, and nuclear magnetic isotropic shieldings, the corresponding chemical shifts, and indirect spin-spin coupling constants were calculated. Several J-couplings observed in proton and carbon NMR spectra, not available before, are reported. The obtained experimental spectra, supported by theoretical calculations, favor the zwitterion form of muscimol in water. This structure differs from NH isomer, previously determined in dimethyl sulfoxide (DMSO) solution. In addition, positions of signals C3 and C5 are reversed in both solvents.

Direct Analysis of Psilocin and Muscimol in Urine Samples Using Single Drop Microextraction Technique In-Line with Capillary Electrophoresis.

The fully automated system of single drop microextraction coupled with capillary electrophoresis (SDME-CE) was developed for in-line preconcentration and determination of muscimol (MUS) and psilocin (PSC) from urine samples. Those two analytes are characteristic active metabolites of Amanita and Psilocybe mushrooms, evoking visual and auditory hallucinations. Study analytes were selectively extracted from the donor phase (urine samples, pH 4) into the organic phase (a drop of octanol layer), and re-extracted to the acidic acceptor (background electrolyte, BGE), consisting of 25 mM phosphate buffer (pH 3). The optimized conditions for the extraction procedure of a 200 µL urine sample allowed us to obtain more than a 170-fold enrichment effect. The calibration curves were linear in the range of 0.05-50 mg L-1, with the correlation coefficients from 0.9911 to 0.9992. The limit of detections was determined by spiking blank urine samples with appropriate standards, i.e., 0.004 mg L-1 for PSC and 0.016 mg L-1 for MUS, respectively. The limits of quantification varied from 0.014 mg L-1 for PSC and 0.045 mg L-1 for MUS. The developed method practically eliminated the sample clean-up step, which was limited only to simple dilution (1:1, v/v) and pH adjustment.

Phytochemical Evaluation of Tinctures and Essential Oil Obtained from Satureja montana Herb.

Winter Savory (Satureja montana L.) has been used in traditional medicine and as a spice or natural food preservative in the Mediterranean region for centuries. In this paper, some technological and analytical aspects of the S. montana tinctures development and an evaluation of the essential oil composition are provided. The total phenolic and flavonoid contents and phenolic compounds profile analyzed spectrophotometrically and by high-performance thin-layer chromatography (HPTLC), respectively, were evaluated in the developed tinctures. The results showed that the tinctures prepared from the S. montana herb by maceration or remaceration are rich in polyphenols, and there is an influence of the technological factors (particle size and extraction mode) on the total phenolic and flavonoid contents. Caffeic, rosmarinic, and chlorogenic acids, (-)-catechin and rutin were identified in the tinctures using the HPTLC method. p-Thymol (81.79%) revealed by gas chromatography-mass spectrometry (GC-MS) was the predominant compound of the essential oil of this plant. Thus, the high contents of polyphenols and flavonoids in the developed tinctures and p-thymol among the volatile components of the S. montana essential oil could indicate the promising antioxidant and antimicrobial properties of these herbal preparations. The obtained results are a ground for the organization of the manufacture of the S. montana tincture and essential oil with the purpose of performing preclinical studies.

Chemical Composition of Two Different Lavender Essential Oils and Their Effect on Facial Skin Microbiota.

Lavender oil is one of the most valuable aromatherapy oils, its anti-bacterial and anti-fungal activities can be explained by main components such as linalool, linalyl acetate, lavandulol, geraniol, or eucalyptol. The aim of the study was to assess the anti-microbial effects of two different lavender oils on a mixed microbiota from facial skin. The commercial lavender oil and essential lavender oil from the Crimean Peninsula, whose chemical composition and activity are yet to be published, were used. Both oils were analysed by gas chromatography coupled to mass spectrometry. The composition and properties of studied oils were significantly different. The commercial ETJA lavender oil contained 10% more linalool and linalyl acetate than the Crimean lavender oil. Both oils also had different effects on the mixed facial skin microbiota. The Gram-positive bacilli were more sensitive to ETJA lavender oil, and Gram-negative bacilli were more sensitive to Crimean lavender oil. However, neither of the tested oils inhibited the growth of Gram-positive cocci. The tested lavender oils decreased the cell number of the mixed microbiota from facial skin, but ETJA oil showed higher efficiency, probably because it contains higher concentrations of monoterpenoids and monoterpenes than Crimean lavender oil does.

Study of biocompatibility of peritoneal dialysis solutions measured as in vitro cells viability.

This paper presents the comparable viability study results of the HepG2 and Vero cells in the presence of traditional peritoneal dialysis (PD) solutions determined by three methods (3-[4,5-dimethylthiazol]-2-yl-2,5-diphenyl tetrazolium bromide (MTT), neutral red (NR) and sulforhodamine B assays) with establishing different correlations between viability and quality indexes of the tested PD solutions. The obtained results confirmed cytotoxicity of the PD solutions even compared with an isotonic solution of sodium chloride. PD solutions action resulted in a similar reduction in the HepG2 and Vero cells. Moreover, this research found that metabolic cellular activity is more vulnerable to the action of PD solutions measured in the MTT-test. One more point is that cytotoxicity is related to pH of a solution and other unknown mechanisms, while glucose degradation products, glucose or lactate did not exert an exceptional negative action on PD solutions cytotoxicity. It is concluded that MTT-test is the best suitable for comparative studies of PD solutions which differ in pH values.

Novel Gel Formulations as Topical Carriers for the Essential Oil of Bidens tripartita for the Treatment of Candidiasis.

The genus Bidens L. (Asteraceae) refers to several species of plants used in traditional phytotherapeutic preparations. B. tripartita, also known as bur marigold, is the most familiar plant and has been known as a remedy for chronic dysentery. The hydrodistilled essential oil of the aerial parts of the Polish B. tripartita was analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques. To exclude any potential toxic effects of the oil on human dermal fibroblasts, the MTT test (methyl thiazolyl tetrazolium) and COMET assay (single-cell gel electrophoresis) were performed. Novel gel formulations as topical carriers for essential oil obtained from B. tripartita were developed and characterized. The bioadhesive properties of the designed preparations in the ex vivo model using the skin of hairless mice were also evaluated. The therapeutic efficacy of the topical formulations is influenced by active phytoconstituents and vehicle characteristics. The antifungal properties of the essential oil of B. tripartita were also tested against Candida species, and this oil appears to be a promising topical anticandidal agent.

A High Sensitivity Preamplifier for Quartz Tuning Forks in QEPAS (Quartz Enhanced PhotoAcoustic Spectroscopy) Applications.

All the preamplifiers dedicated for Quartz Enhanced PhotoAcoustic Spectroscopy (QEPAS) applications that have so far been reported in the literature have been based on operational amplifiers working in transimpedance configurations. Taking into consideration that QEPAS sensors are based on quartz tuning forks, and that quartz has a relatively high voltage constant and relatively low charge constant, it seems that a transimpedance amplifier is not an optimal solution. This paper describes the design of a quartz QEPAS sensor preamplifier, implemented with voltage amplifier configuration. Discussion of an electrical model of the circuit and preliminary measurements are presented. Both theoretical analysis and experiments show that use of the voltage configuration allows for a substantial increase of the output signal in comparison to the transimpedance circuit with the same tuning fork working in identical conditions. Assuming that the sensitivity of the QEPAS technique depends directly on the properties of the preamplifier, use of the voltage amplifier configuration should result in an increase of QEPAS sensitivity by one to two orders of magnitude.

Chemical Composition of Herbal Macerates and Corresponding Commercial Essential Oils and Their Effect on Bacteria Escherichia coli.

This study addresses the chemical composition of some commercial essential oils (clove, juniper, oregano, and marjoram oils), as well as appropriate herbal extracts obtained in the process of cold maceration and their biological activity against selected Escherichia coli strains: E. coli ATTC 25922, E. coli ATTC 10536, and E. coli 127 isolated from poultry waste. On the basis of the gas chromatography-mass spectrometry (GCMS) analysis, it was found that the commercial essential oils revealed considerable differences in terms of the composition and diversity of terpenes, terpenoids and sesquiterpenes as compared with the extracts obtained from plant material. The commercial clove, oregano, and marjoram oils showed antibacterial properties against all the tested strains of E. coli. However, these strains were not sensitive to essential oils obtained from the plant material in the process of maceration. The tested strains of E. coli show a high sensitivity, mainly against monoterpenes (α-pinene, ß-pinene, α,ß,γ-terpinene, limonene) and some terpenoids (thymol, carvacrol). The commercial juniper oil contained mainly monoterpenes and monoterpenoids, while the extracts contained lower amounts of monoterpenes and high amounts of sesquiterpenes-the anti-microbiotic properties of the juniper herbal extract seem to be caused by the synergistic activity of mono- and sesquiterpenes.

Emergence of Pseudomonas aeruginosa with class 1 integron carrying blaVIM-2 and blaVIM-4 in the University Clinical Hospital of Bialystok (northeastern Poland).

The effectiveness of carbapenems, considered as last-resort antimicrobials in severe infections, becomes compromised by bacterial resistance. The production of metallo-ß-lactamases (MBLs) is the most significant threat to carbapenems activity among Pseudomonas aeruginosa. The aim of this study was to assess the presence and type of MBLs genes in carbapenem-resistant P. aeruginosa clinical strains, to identify the location of MBLs genes and to determine genetic relatedness between MBL-producers using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The first identified MBL-positive (with blaVIM genes) P. aeruginosa strains were isolated from patients hospitalized in the University Clinical Hospital of Bialystok in the period from September 2012 to December 2013. Variants of MBLs genes and variable integron regions were characterized by PCR and sequencing. PFGE was performed after digesting of bacterial genomes by XbaI enzyme. By MLST seven housekeeping genes were analyzed for the determination of sequence type (ST). Three strains carried the blaVIM-2 gene and one harbored the blaVIM-4 gene. The blaVIM genes resided within class 1 integrons. PCR mapping of integrons revealed the presence of four different cassette arrays. Genetic relatedness analysis by PFGE classified VIM-positive strains into four unrelated pulsotypes (A-D). MLST demonstrated the presence of four (ST 111, ST27, and ST17) different sequence type including one previously undescribed new type of ST 2342. Antimicrobial susceptibility testing showed that VIM-positive strains were resistant to carbapenems, cephalosporins, aminoglycosides, and quinolones, intermediate to aztreonam, and susceptible only to colistin. Integrons mapping, PFGE, and MLST results may point to different origin of these strains and independent introduction into hospitalized patients.

Identification of plasmid OXA and other ß-lactamase genes among carbapenem-resistant isolates of Pseudomonas aeruginosa from the Clinical University Hospital in northeastern Poland.

The aim of the study was to evaluate the prevalence of OXA and other ß-lactamase genes, antibiotic susceptibility, and the genetic relatedness among clinical isolates of P. aeruginosa resistant to carbapenems. The presence of bla- OXA genes was demonstrated in 48% of isolates belonging to four PFGE profiles. Most of them contained the blaOXA-2 gene (88.3%). Other blaOXA genes (Ps1310 with blaOXA-30 and Ps1309 with blaOXA-10) were found in only two isolates. The tested isolates also contained other ß-lactamase genes such as blaVIM-2, blaVIM-4, blaSHV-5, and blaTEM-1. All isolates were susceptible only to colistin (100%).

Determination of muscimol and ibotenic acid in mushrooms of Amanitaceae by capillary electrophoresis.

In this study, the CZE method for rapid quantitative and qualitative determination of ibotenic acid and muscimol in Amanita mushrooms naturally grown in Poland was developed. The investigations included the species of A. muscaria, A. pantherina, and A. citrina, collected in southern region of Poland. The studied hallucinogenic compounds were effectively extracted with a mixture of methanol and 1 mM sodium phosphate buffer at pH 3 (1:1 v/v) using ultrasound-assisted procedure. The obtained extracts were separated and determined by CZE utilizing a 25 mM sodium phosphate running buffer adjusted to pH 3 with 5% content of acetonitrile v/v. The calibration curves for both analytes were linear in the range of 2.5-7000 µg/mL. The intraday and interday variations of quantitative data were 1.0 and 2.5% RSD, respectively. The recovery values of analyzed compounds were over 87%. The identities of ibotenic acid and muscimol were confirmed by UV spectra, migration time, and measurements after addition of external standard.

In vitro activity of rifampicin alone and in combination with imipenem against multidrug-resistant Acinetobacter baumannii harboring the blaOXA-72 resistance gene.

BACKGROUND: The growing incidence of multidrug resistance (MDR) in bacteria is an emerging challenge in the treatment of infections. Acinetobacter baumannii is an opportunistic pathogen prone to exhibit MDR that contributes significantly to nosocomial infections, particularly in severely ill patients. Thus, we performed research on rifampicin activity against selected MDR OXA-72 carbapenemase-producing A. baumannii strains. Since it is widely accepted that rifampicin should not be used as monotherapy in order to avoid the rapid development of rifampicin resistance, we evaluated the efficacy of combination therapy with imipenem. METHODS: Minimal inhibitory concentrations (MICs) of both rifampicin and imipenem were determined by use of the broth microdilution method. Evaluations of the interactions between rifampicin and imipenem were performed by analysis of the fractional inhibitory concentration index (∑FIC), determined using the checkerboard titration method. RESULTS: All tested isolates showed full susceptibility to rifampicin. The checkerboard method revealed synergism in 5 isolates (29%) and an additive effect in another 5 isolates (29%); no difference was reported in the remaining 7 isolates (41%). Strains moderately resistant to imipenem (MIC ≤ 64 mg/l) tended to show synergy or additive interaction. CONCLUSIONS: We conclude that in vitro synergism or an additive interaction between rifampicin and imipenem most likely occurs in A. baumannii strains showing moderate resistance to imipenem (MIC ≤ 64 mg/l). Moreover, utilizing this combination in the therapy of infections caused by strains exhibiting higher levels of resistance (MIC > 64 mg/l) is not recommended since in this setting imipenem could not prevent the development of rifampicin resistance.