Current Issue : January-March Volume : 2025 Issue Number : 1 Articles : 5 Articles
Background/Objectives: Oreganum vulgare essential oil (OEO) is safe, effective, multifunctional, and widely used. This study aimed to evaluate OEO’s chemical composition and antimicrobial activity in vitro against S. aureus and E. coli. Methods: The composition of OEO was determined by gas chromatography–mass spectrometry (GC-MS). Results: Compounds included monoterpenes with known antimicrobial activity, such as 2-menthen-1-ol (36.33%), linalyl acetate (9.26%), terpinene- 4-ol (9.01%), 4-thujanol (6.33%), menthen (5.81%), sabinene (5.18%), and carvacrol methyl ether (5.14%). Conclusions: OEO had a strong antimicrobial activity with a minimum inhibitory concentration (MIC) of 1.90 mg/mL for S. aureus and 0.49 mg/mL for E. coli after 18 h incubation. The minimum bactericidal concentration (MBC) was 7.9 mg/mL against S. aureus and 0.99 mg/mL against E. coli. Thus, OEO could be used as a natural antimicrobial against S. aureus and E. coli infections....
The present study tested sildenafil citrate as an example of pharmacological repositioning against the opportunistic pathogen Pseudomonas aeruginosa, known for its potent biofilm formation. We evaluated its antimicrobial, synergistic, and antibiofilm effects using broth microdilution, checkerboard assays, and atomic force microscopy techniques. Sildenafil citrate showed antimicrobial activity, effectively inhibiting bacterial growth at minimum inhibitory concentrations ranging from 3.12 to 6.25 mg/mL and minimum bactericidal concentrations between 3.12 and 25 mg/mL. When combined with reference antimicrobial agents—cefepime, imipenem, cilastatin, and polymyxin—sildenafil citrate had a synergistic effect. It also effectively inhibited and eradicated biofilms, reducing total biomass by 87.1% for inhibition and 83.8% for eradication. Atomic force microscopy confirmed the efficacy of sildenafil citrate in destroying and inhibiting biofilms, decreasing the overall amplitude of the biofilm. Consequently, sildenafil citrate appears to be a promising candidate for combination with commercial antimicrobial drugs to prevent and treat P. aeruginosa infections....
In this study, we aimed to assess the activity of the essential oils from four Bulgarian oil-bearing roses Rosa damascena Mill., R. alba L., R. centifolia L., and R. gallica L., on the reference strain Mycobacterium tuberculosis H37Rv and clinical M. tuberculosis strains of the Beijing and Latin-American Mediterraneum genotypes. The chemical composition of the essential oils was determined by gas chromatography (GC-FID/MS). Minimal inhibitory concentrations (MIC) were determined using the resazurin method. R. alba oil showed the highest inhibitory activity when tested on all strains of different phylogenetic origins with MIC in the range of 0.16–0.31 mg/mL, while R. gallica oil was the least active (MIC 0.62–1.25 mg/mL). The obtained results show heterogeneity of rose oil action on different mycobacterial strains and we hypothesize that the combined level of geraniol and nerol is a key factor that underlies the antimycobacterial action of the rose oils. Strain Beijing 396 was relatively more susceptible to the rose oils probably due to multiple and likely deleterious mutations in its efflux pump genes. Two clinical MDR strains have likely developed during their previous adaptation to anti-TB drugs certain drug tolerance mechanisms that also permitted them to demonstrate intrinsic tolerance to the essential oils. Further research should investigate a possible synergistic action of the new-generation anti-TB drugs and the most promising rose oil extracts on the large panel of different strains....
Background/Objective: Narrow-spectrum beta-lactam antibiotics such as benzylpenicillin and flucloxacillin are increasingly used in outpatient parenteral antimicrobial therapy (OPAT) programs to mitigate the adverse effects associated with broad-spectrum antibiotics. These beta-lactams require continuous administration via portable infusion devices during OPAT. However, the use of benzylpenicillin in OPAT requires special consideration because of its limited stability at elevated temperatures. Methods: We tested the benzylpenicillin stability, pH, and degradation of products in elastomeric pumps at different concentrations in saline and in buffered solution containing sodium citrate during a prolonged storage and at high temperatures (seven days at 2–8 ◦C followed by 24 h at 37 ◦C). Additionally, drug concentrations during intermittent bolus infusion and during OPAT were determined in five patients. The concentrations and degradation products of benzylpenicillin were measured using liquid chromatography mass spectrometry (LC-MS/MS). Results: Unbuffered benzylpenicillin solutions that were already degraded during refrigerator storage and analyte concentration were not measurable after 8 days. The stability of the buffered solutions was acceptable at all three of the tested concentrations (97.6 ± 1.3%, 96.3 ± 0.8%, and 94.9 ± 1.1% for 10 Mio IU, 20 Mio IU, and 40 Mio IU of benzylpenicillin). The stability was influenced by benzylpenicillin concentration, and several breakdown products were identified. Benzylpenicillin concentrations were measured in five patients during OPAT and ranged from 7.2 to 60 mg/L. Conclusions: Benzylpenicillin buffered with sodium citrate is a safe and convenient option for use in continuous infusions during OPAT and should be favored over broad-spectrum antibiotics. Therapeutic drug monitoring data indicate sufficient to high plasma levels when patients received benzylpenicillin as continuous infusions....
Background: The repurposing of approved drugs for new activities is gaining widespread attention, including drugs that have antibacterial properties. Nevertheless, besides the benefits of repurposing drugs, the discovery of new antibiotic activity in commonly used medicines raises concerns about inducing antibiotic tolerance and resistance due to the stress produced by the drugs. We found that nebivolol, which is used to treat hypertension, also has antibacterial activity. Methods: The antibacterial activity of nebivolol was tested by disc diffusion and kinetic O.D. measurements. Antibiofilm activity was determined by crystal violet staining. Results: Nebivolol has antibiotic and antibiofilm activity against several bacteria. However, its effect on Pseudomonas aeruginosa’s growth is limited, and it promotes biofilm formation. In addition, P. aeruginosa exposure to nebivolol induces resistance to ciprofloxacin but increases sensitivity to tobramycin. Conclusions: Nebivolol has antibiotic activity against several bacteria tested but is less effective and possibly detrimental in P. aeruginosa infections. The use of nebivolol, together with other antibiotics, should be further tested and carefully considered....
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