Current Issue : April-June Volume : 2025 Issue Number : 2 Articles : 5 Articles
Background: Essential oils exhibit several biological activities such as antimicrobial, antioxidant, proliferative, and anti-inflammatory. This study was aimed at investigating the antimicrobial effects and cytotoxic activities of niaouli, palmarosa, and clove essential oils. Methods: Content analyses of these essential oils were carried out by gas chromatography–mass spectrometry. The antibacterial activity was screened against methicillin-resistant S. aureus ATCC 43300, P. aeruginosa ATCC 27853, P. aeruginosa PAO1, S. aureus ATCC 25923, and 44 isolates (22 P. aeruginosa isolates, 4 S. aureus isolates, and 18 Staphylococcus spp. isolates) obtained from dogs with previous wound infections who were included in the current study. The antimicrobial effects of essential oils were investigated using disk diffusion and minimum inhibition/bactericidal concentration methods. Additionally, the antibiofilm, protease, elastase, and gelatinase activities of the essential oils were evaluated. Different concentrations of each essential oil ranging from 10 to 1000 μg/mL were also analyzed in terms of cell viability by WST-8 assay in primary canine fibroblast cells. Results: The fibroblast cell viabilities of palmarosa, niaouli, and clove oils at a 1000 μg/mL concentration were 75.4%, 96.39%, and 75.34%, respectively. All the EOs were found to have bactericidal effects with MBCs/MICs of 0.015 to 0.5 μL/mL against P. aeruginosa, Staphylococcus isolates (p < 0.001). Palmarosa was found to have the largest inhibition zone diameter (20.5 ± 6.6, 16.4 ± 2.3) compared to other essential oils in the disk diffusion test against Staphylococcus spp. and P. aeruginosa (p < 0.001). But none of the EOs reduced protease, elastase, and gelatinase activities, which are some of the virulence properties of the tested bacteria. Conclusions: These results showed that palmarosa, niaouli, and clove essential oils act as potential antibacterial agents for dogs against P. aeruginosa, methicillin-resistant S. aureus, and Staphylococcus spp., without damaging the skin....
Acinetobacter species are major pathogens responsible for hospital-acquired infections. This study aimed to compare the clinical characteristics, outcomes, and antimicrobial resistance between Acinetobacter baumannii (AB) and non-baumannii Acinetobacter (NBA) species. In this retrospective cohort study, we analyzed data from adult patients (aged 18 or older) with Acinetobacter bacteremia treated at two tertiary hospitals from July 2020 to November 2023. Among 260 cases of Acinetobacter bacteremia, 42 (16.2%) involved NBA species. The AB group exhibited higher antimicrobial resistance rates across all tested agents, except for minocycline. Female patients, younger patients, and those with catheter-related infections were more commonly observed in the NBA group than in the AB group, while pneumonia and septic shock were more prevalent in the AB group. In a multivariable analysis of 30-day mortality, factors associated with higher mortality included moderate to severe liver disease, chronic kidney disease, carbapenem resistance, septic shock, and higher Pitt Bacteremia Scores. When stratified by carbapenem resistance (CR) status, only CR-AB exhibited significantly lower 30-day survival rate (33.4%) compared to that of the other groups (non-CR-NBA, 77.3%; CR-NBA, 77.8%; non-CR-AB, 90.1%; p < 0.001). Our findings highlight distinct clinical differences between AB and NBA bacteremia cases; however, the mortality rate for non-CR-AB was comparable to that observed in NBA bacteremia....
Background: The burden of prosthetic joint infection in combination with antibiotic- resistant bacterial strains is a rising dilemma for patients experiencing total joint replacements. Around 0.8%2% of patients experience prosthetic joint infections, while up to 21% of patients are considered fatal cases after 5 years. Staphylococcus aureus is one of the main reasons for prosthetic joint infections. Its capability of forming biofilms and developing mechanisms against antibiotics is one of the most dangerous clinical topics being currently discussed. Previous studies have shown the promising results of omega- 3 fay acids as an antimicrobial agent against Staphylococcus aureus. Though an antimicrobial effect has been examined, the influence of polyunsaturated fay acids on Staphylococcus aureus in the presence of human osteoblasts has not been reported yet. In this study, we aimed to investigate the influence of omega-3 fay acids on the biofilm formation of Staphylococcus aureus ATCC 29213 in the presence of hFOB 1.19 cells. The co-culture setup helped to examine the influence of omega-3 fay acids on the race for surface to simulate prosthetic joint infections. Methods: In this study, we tested Staphylococcus aureus ATCC 29213 co-cultured with human fetal osteoblasts hFOB 1.19 in the presence of sub-MIC and MIC concentrations of docosahexaenoic acid (1.25 mg/L, 2.5 mg/L) and eicosapentaenoic acid (0.15 mg/L, 0.3 mg/L) after 1, 6 and 24 hours of incubation. After establishing the coculture, cell culture and biofilm, we performed colony-forming unit counting and cell counting to examine cell survivability. In addition, we carried out scanning electron microscopy to study the race for surface behaviour of the cells. Results: We found a protective influence of omega-3 fay acids on osteoblasts when present in co-culture with Staphylococcus aureus after 6 hours of incubation. Omega-3 fay acids increase the cell survival of osteoblasts after 6 hours in a co-culture with bacteria and are able to influence the race for surface. In this study, the strain of Staphylcoccus aureus ATCC 29213 showed signs of growth inhibition within the first 6 hours. Conclusion: Omega-3 fay acids can be a valuable antimicrobial agent in terms of decreasing the risk of on-site infection during surgery. Omega-3 fay acids were shown to decrease the bacterial load within the first 6 hours of incubation and increase the survivability of osteoblasts....
Currently, a global health crisis is being caused by microbial resistance, in which Acinetobacter baumannii plays a crucial role, being considered the highest-priority microorganism by the World Health Organization (WHO) for discovering new antibiotics. As a result, phytochemicals have emerged as a potential alternative to combat resistant strains, since they can exert antimicrobial activity through various mechanisms and, at the same time, represent a more natural and safe option. This study analyzes the antimicrobial effects of guava leaf extract in ten clinical isolates of extensively drug-resistant (XDR) A. baumannii, using the agar diffusion technique and the microdilution method to determine the minimum inhibitory concentrations (MICs). Additionally, possible improvements in antimicrobial activity after the purification of polyphenolic compounds and potential synergy with the antibiotic gentamicin are examined in this research. Moreover, the effect of the plant extract in cell line A549 derived from lung tissue was also evaluated. The extract exhibited antimicrobial activity against all the strains studied, and the purification of polyphenols along with the combination with gentamicin improved the extract activity. The presence of the plant extract induced morphological changes in the lung cells after 24 h of exposure. Therefore, Psidium guajava L. leaf extract is a potential antimicrobial agent....
Background: Antimicrobial peptides are generally considered promising drug candidates for combating resistant bacterial infections. However, the selectivity of their action may vary significantly. Natural gomesin, isolated from haemocytes of the tarantula Acanthoscurria gomesiana, demonstrates a broad spectrum of antimicrobial activities, being the most effective against pathogenic fungi. Methods: Here, we searched for variants of natural gomesin-like peptides and produced their recombinant analogs in the bacterial expression system. The antimicrobial activities of the obtained peptides were tested against a panel of bacterial and yeast strains, and their toxicity towards human cells was examined. Results: Most of the new analogs of gomesin have primary structures homologous to that of the natural gomesin; however, they have fewer amino acid residues and post-translational modifications. One of the discovered analogs, the His-rich shorter peptide from the spider Dysdera sylvatica, designated as DsGom, displays antifungal activity comparable with that of natural gomesin. In the process of the structural–functional study of DsGom, it was shown that this analog retains a basic mechanism of action similar to that of natural gomesin. The DsGom analog has a significantly better toxicity profile as compared to gomesin. At the same time, the loss of the first Arg residue reduces, but does not annul, the antifungal activity of DsGom. Moreover, the acidification of the growth medium reduces the loss of the antifungal activity of this analog. Conclusions: The discovered natural gomesin-like peptides display more selective antifungal activities as compared to gomesin. The low cytotoxicity of DsGom, combined with its high antifungal activity and stability, allows us to consider it a promising drug candidate for the treatment of fungal infections, especially those caused by fungi of the Candida genus....
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