Background: Besides the viral infections, bacterial infections can cause serious and lifethreatening complications and drug resistance is an important problem to fight bacterial infections. Therefore, it is important to discover novel antimicrobial agents to fight such infections. Objective: Several indole containing antimicrobial drug development studies have been reported in literature that provided strong evidence for good antimicrobial activities against a variety of microorganisms. Taken into consideration from these findings, antimicrobial properties of previously synthesized 16 indole amide derivatives were evaluated by in vitro tests against 14 different microorganisms, and also molecular docking and in silico prediction studies were used to identify structure-activity relationship of compounds. Methods: Antimicrobial activity of compounds was determined by disc diffusion and tube dilution methods. Molecular docking of compounds was studied to determine the relationship between the structure of compounds with DNA gyrase interactions of microorganisms by using the version of Autodock vina 4.2.6. Mol inspiration and Swiss ADME prediction online software programs were also used to identify drug-like properties of compounds. Results: The results showed that some compounds exhibited quite pronounced antibacterial and antifungal activities compared to reference drugs. These results were also supported by molecular docking studies and in silico ADME calculations presented that all tested compounds obey Lipinski’s Rule of Five and are metabolized by CYP450 enzymes. Conclusion: It can be concluded that these results can be taken as a reference in the development of new indole-based antimicrobial agents.

Background: The escalation of multidrug-resistant (MDR) Klebsiella pneumoniae infections poses a severe global health threat, necessitating the exploration of alternative therapeutic strategies such as drug repurposing. This study aims to investigate the intrinsic antibacterial activity of the antidiabetic drug metformin and its adjuvant potential when combined with conventional antibiotics against K. pneumoniae. Materials and Methods: The antimicrobial effects of metformin were evaluated against the reference strain K. pneumoniae ATCC 700603 and an MDR clinical isolate obtained from an intensive care unit. Minimum Inhibitory Concentration (MIC) values were determined using the microdilution method. Interaction studies between metformin and three antibiotics (Levofloxacin, Amikacin, and Ceftazidime) were conducted using the checkerboard assay. The results were interpreted based on the Fractional Inhibitory Concentration Index (FICI). Results: Metformin monotherapy exhibited weak intrinsic antibacterial activity (MIC ≥ 500 µg/mL) against both the reference strain and the clinical isolate. In combination assays, metformin demonstrated an antagonistic effect with Levofloxacin, while its interactions with Amikacin and Ceftazidime were classified as indifferent. The observed antagonism with Levofloxacin is attributed to metformin’s antioxidant properties, which likely mitigate the oxidative stress required for the bactericidal action of fluoroquinolones. Furthermore, the lack of synergy with Amikacin suggests that metformin-induced disruption of the Proton Motive Force (PMF) may hinder the intracellular uptake of aminoglycosides. Conclusion: The findings indicate that metformin is ineffective as a standalone antibacterial agent against K. pneumoniae. Moreover, its adjuvant potential is highly dependent on the antibiotic class and strain-specific resistance mechanisms. Contrary to some reports of synergy, this study highlights the risk of antagonism, particularly with fluoroquinolones. Further standardized mechanistic studies are required to define the specific therapeutic windows for metformin as an antimicrobial adjuvant.

Ultra işlenmiş besinler biyoaktif bileşikler, mikro besin ögeleri ve lifler açısından fakir; şeker, yağ ve sodyum açısından zengin besinlerdir. Ultra işlenmiş besinleri oluşturan bileşenlerin çoğu koruyucular, emülgatörler, çözücüler, stabilizatörler, tatlandırıcılar, duyusal özellik arttırıcılar ve renklendiriciler gibi gıda katkı maddeleridir. Son yıllarda bu besinlerin tüketiminde artış görüldüğü bilinmektedir. Basit şeker ve yağ tüketimindeki artış; lif tüketimindeki azalma bağırsak mikrobiyotasının kompozisyon ve fonksiyonlarındaki değişikliklerle doğrudan ilişkilidir. Bu durum bağırsak geçirgenliğini arttırabilir. Ultra işlenmiş besin tüketimi ile obezite, yüksek tansiyon ve kanser gibi bulaşıcı olmayan kronik hastalıkların görülme sıklığı arasında da bir ilişki olduğu ifade edilebilir. Gıda katkı maddelerinin deney hayvanlarında bağırsak mikrobiyotası çeşitliliğini azalttığına dair çalışmalar bulunmaktadır fakat insanlarda ultra işlenmiş besinlerin ve gıda katkı maddelerinin mikrobiyotaya direkt etkisi üzerine yeteri kadar çalışma bulunmamaktadır. Bu derlemenin amacı ultra işlenmiş besin tüketiminin ve özellikle gıda katkı maddelerinin mikrobiyota üzerindeki etkilerini literatür eşliğinde incelemektir.

Background/aim: This study evaluates the challenges associated with overcoming antimicrobial resistance and innovative approaches to combat multidrug-resistant (MDR) bacterial infections. Materials and methods: Novel codoped carbon quantum dots (CCQDs) were synthesized using citric acid as the carbon source and L-cysteine as the nitrogen codoping atom. The formulation in which citric acid was retained was designated as CCQDs-1, whereas the purified version, from which citric acid was removed, was termed CCQDs-2. The antibacterial properties of CCQDs-1 and CCQDs-2 were compared using the agar well diffusion method. This study comprehensively characterizes these nanomaterials and evaluates their antibacterial potential, both alone and in combination with antibiotics, against a spectrum of gram-positive (G+) and gram-negative (G‒) bacterial strains. Results: The study demonstrates the significant antibacterial efficacy of CCQDs, with notable variations observed between citric acid-containing and citric acid-neutralized formulations. The QDs exhibited remarkable characteristics, including a quantum yield of 90.3%–90.6%, intense fluorescence, and distinctive interactions with various antibiotics. In addition to their intrinsic antibacterial activity, the QDs also exhibited synergistic effects when combined with certain antibiotics. A synergistic effect was particularly observed when CCQDs-2 were combined with antibiotics such as gentamicin, levofloxacin, and clindamycin, suggesting potential mechanisms such as membrane permeability disruption and efflux pump saturation. Conclusion: These findings underscore the promising potential of carbon-based QDs as innovative, biocompatible solutions to address the critical global challenge of antimicrobial resistance.