Antibacteria and Antibiofilm Properties of Tetracycline Loaded Niosomes against Klebsiella Pneumoniae Isolates: A Laboratory Study Elham Bazargan[1], Fatemeh Ashrafi[2], Elham Siasi Torbati[3] Received: 05/11/23 Sent for Revision: 13/03/24 Received Revised Manuscript: 22/06/24   Accepted: 24/06/24 Background and Objectives: Biofilm production is one of the reasons for drug resistance in bacteria. The aim of the present study was to synthesize niosomal structures containing tetracycline antibiotic and determine its effect on Klebsiella pneumoniae drug-resistant isolates in an effective treatment system. Materials and Methods: In this laboratory study, nanoniosomes containing tetracycline (Tet-Nio) were synthesized using the thin layer hydration method, and the morphological characteristics of drug release was investigated. MIC (Minimum inhibitory concentration), crystal violet, MBEC (Minimum biofilm eradication concentration) tests were used to investigate the Antibacterial and anti-biofilm effects against Klebsiella pneumoniae strains under study exposed to free tetracycline and Tet-Nio, and the expression of mrkA gene in 10 isolates using was evaluated by real-time PCR test. One-way analysis of variance was used to analyze the data. Results: Formulation No. 2 with the particle size of 169. 45±9. 55 nm, polydispersity index (PDI) equal to 0. 168±0. 010, Zeta-potential equal to-24. 55±1. 63, entrapment efficacy equal to 75. 31%±1. 48%, and tetracycline drug release percentage in 48 hours equal to 45. 34%±1. 15% was chosen as the optimal formulation. The microbial test results showed that the Tet-Nio structure has more Antibacterial effects than the free drug. Also, it was stated that the optimal formulation of Tet-Nio can significantly reduce the formation of biofilm in Klebsiella pneumoniae pathogenic bacteria by reducing the expression of the mrkA gene compared to the drug-treated group (p<0. 001). Conclusion: Niosomes containing tetracycline were able to inhibit biofilm formation in drug-resistant isolates of Klebsiella pneumoniae. Therefore, they can be used in clinical studies to deal with nosocomial infections caused by Klebsiella pneumoniae isolate.

Enoxolone is a major component of a traditional plant called Licorice. This substance has been found to contain some pharmaceutical properties including of both antiviral and antifungal activities. Microbiological studies have identified more than seven periodontopathogens in the periodontal pockets, which less than 4 species were capnophile. The purpose of this study was to investigate the in vitro Antibacterial effects of enoxolone against isolated periodontopathogenic and capnophilic bacteria. Total specimens were collected with sterile paper points from the deepest periodontal pockets of 400 patients, and cultured under capnophilic condition using selective media. The isolates were characterized to species level by conventional biochemical tests. Antibacterial activities of enoxolone against those microorganisms were investigated by determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. In this study, 186 species of Actinobacillus actinomycetemcomitans (46.5%), 120 species of Eikenella corrodens (30%) and 136 Capnocytophaga species (34%) were isolated from specimens of periodontitis patients. The rate of periodontitis specimens associated with monobacteria and polybacteria were 105 (26.3%) and 158 (39.5%), respectively. The MIC of enoxolone was 8, 16 and 8 mg/ml for A. actinomycetemcomitans, E. corrodens and Capnocytophaga species, respectively and the MBC was 16 mg/ml for all species. It is concluded that enoxolone with above mentioned concentration is effective against isolated periodontopathogenic and capnophilic bacteria.

Background and Objectives Actinobacteria efficiently can produce different nanoparticles with various biological properties due to their ability to produce secondary metabolites. The present study aimed to examine the isolation and screening of gold nanoparticles via producing actinobacteria from the soil. We also studied their Antibacterial activities. Methods In this study, after the isolation of actinobacteria, the accumulation of gold nanoparticles was investigated. This aim was achieved by changing the color of the reaction medium and its adsorption by UV-visible spectrophotometry. Then, for conducting confirmatory tests, ultraviolet and visible absorption spectroscopy, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and dynamic light scattering analysis was used. Phenotypic and molecular methods were applied to study the nanoparticle-producing actinobacterium isolate. The Antibacterial activity of synthesized gold was explored on pathogenic bacteria. Results Among the examined 35 Actinobacteria strains, one strain was biosynthesized nanoparticles; it indicated the maximum absorption at 537 nm, i. e., the characteristic of gold nanoparticles. Dynamic light scattering analysis revealed an average size of 44. 4 nm. The minimum inhibitory concentration of gold nanoparticles against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus was 5. 8μ g/mL, 11. 7μ g/mL, and 11. 7μ g/mL, respectively. Molecular analysis data revealed that the Actinobacteria isolate was Amycolatopsis sp. KMN. The isolate Amycolatopsis sp. strain KMN presented 99. 82% homology to Amycolatopsis methanolica239. Conclusion Overall, according to the obtained results, nanoparticles biosynthesized using Actinobacter cell extract suggested different properties, making them a suitable candidate for further research concerning nanomedicines

Introduction: Arctium lappa (Great burduck) and Artemesia absinthium are medicinal plants that some of their Antibacterial and antivirus properties have been suggested in nutritional industries. The objective of this research was to study the effects of A. lappa and A. absinthium on some microorganisms including Pseudomonads aeraginosa, Haemophilus influenza, Bacillus subtilis, Bacillus cereus, Klebsiella pneumonia and Staphylococcus aureus.Methods: Extracts were prepared by maceration method and tested on Mueller Hinton agar medium based on disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by micro-dilution method. Antibiotic disks used for controlling and standardizing the examination.Results: The extracts of A. lappa and A. absinthium had significant effect on S. aureus. The MIC and MBC concentrations of the extract of A. lappa on B. subtilis were respectively 600 and 750 mg/ml. Also, these values were 230 and 540 mg/ml for H. influenza. Extract of A. absinthium showed more inhibitory effect on B. subtilis. All extracts showed inhibitory effect on B. cereus. The extracts of A. lappa and A. absinthium had inhibitory effects on H. influenza and P. aeraginosa. Among antibiotics, only Ofloxacin and Ciprofloxacin had effects on H. influenza. Extract of A. lappa showed flimsy effect on K. pneumonia, while extract of A. absinthium had no effect on this bacterium.Conclusion: Due to the effects of A. lappa and A. absinthium on some bacteria, they might be good substitutes for synthetic substances.

Introduction: Today, the biosynthesis of nanoparticles (NPs) assisted by microorganisms (particularly bacteria) received increasing attention. In this study, Bacillus subtilis strain SFTS, a bismuth-reducing bacterium, was isolated from the soil of a copper mine in the South of Iran and used for biosynthesis of bismuth NPs (Bi NPs). Materials and methods: Bacillus subtilis strain SFTS was identified by conventional identification tests and the 16S rDNA fragment amplification method. Characterizations of the bio-fabricated Bi NPs were examined using FTIR, EDS, XRD, TEM, and SEM analysis after purification of Bi NPs. In addition, the synergistic effect of biogenic Bi NPs in combination with different antibiotics was also investigated. Results: The attained results revealed that the biosynthesized Bi NPs average size was 22. 36 nm and spherical in shape. The XRD pattern showed that the biosynthesized nanoparticles consisted only of Bi4 and monoclinic crystals. Furthermore, the results of Antibacterial effect of Bi NPs in combination with various antibiotics showed that the nanoparticles represented the highest synergistic effect together with imipenem and the lowest effect in combination with tetracycline against clinical strains of E. coli and K. pneumoniae. Significant difference between synergistic effect of Bi NPs with antibiotics compared to antibiotics disc alone against E. coli and K. pneumoniae strains was observed (P<0. 001). Conclusion: This study showed that Bi NPs biologically synthesized by Bacillus subtilis strain SFTS had a small size and different structure. However, finding about their Antibacterial effect and related mechanism merit further investigations.

The aim of this study was to evaluate the Antibacterial activity of the water extracts of three species of Salvia (S. perspolitana, S. palaestina, S. bracteata) on Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa. The Antibacterial activity of water extracts of the studied species on the bacterial strains was examined using well diffusion method and minimum inhibitory concentration (MIC). Results showed that only S. bracteata formed growth inhibitory zone (9 mm) on Staphylococcus aureus. The extracts of all three plants formed growth inhibitory zone on E. coli and P. aeroginosa. The extract of S. bracteata was more effective than that of the other species. Results for MIC also showed that the extracts of S. perspolitana had the lowest effect on St. aureus and its MIC was observed in a concentration of 1024 μ g/ml. The extracts of this species had the inhibitory effect in a concentration of 256 μ g/ml. The uppermost inhibitory effect was provided by the extract of S. bracteata, since the minimum inhibitory concentration of this species for S. aureus was equal to 64 μ g/ml; and for the other two bacteria, it was equal to 128 μ g/ml. The extracts of S. palaestina had the lowest effect on S. aureus and its MIC was observed in a concentration of 1024 μ g/ml. The extracts of this species had an MIC equal to 512 μ g/ml for the other two bacteria. It was concluded that S. bracreata could be considered a suitable species with anti-bacterial activities in future researches.

Objective(s): In Indonesia, the incidence of bone injuries as a result of traffic accidents is quite high. This necessitates the use of bone implants, which are frequently made of Stainless Steel 316L ( SS316L). The probability of contracting an infection when implanting an SS316L implant has been increasing. Infection due to implant placement is called osteomyelitis which is bone inflammation caused by biofilms formed by pyogenic bacteria. Biofilms can be prevented by giving Antibacterial agents. This research aims to explore silver nanoparticles (AgNPs) as an Antibacterial agent in SS316L implants. Methods: AgNPs are synthesised using the Gallic acid reduction technique. AgNPs solution added with gelatin was misted on SS316L with five different precursor concentrations (0. 1, 1, 10, and 100 mM) using the airbrush spray coating approach with a distance of 20 cm between the nozzle and the substrate and a pressure of 40 psi. Results: AgNPs solutions produced from various concentrations of AgNO3 precursors have a broad spectrum of excitation maximums (λ max = 401. 5 nm-424. 5 nm) and crystallite size in the range of 0. 97-4. 88 nm. The AgNPs layer on SS316L was characterized for their crystalline phase, crystal size, and Antibacterial activity. It has a cubic structure with a phase fraction of 6. 5-19%. The inhibition zone radius for AgNPs coated samples is in the range of 12-16 mm. The combination coating of AgNPs (10 mM) and gelatin layer seemed to have the best Antibacterial ability, with an inhibition zone diameter of 16. 63 mm. Conclusions: It is imperative to generate concentration variation of the 10 mM AgNPs precursor-Gelatin to be used to as coating layer on the SS316L restorative surface.