Association of perturbation of oral bacterial with incident of Alzheimer's disease: A pilot study.

OBJECTIVE: This case-control study was designed to compare the composition of the predominant oral bacterial microbiome in Alzheimer's disease (AD) and control group. SUBJECT: A total of 30 adult participants (15 AD and 15 healthy individuals) were entered in this study. The composition of oral bacterial microbiome was examined by quantitative real-time polymerase chain reaction (qPCR) using bacterial 16S rDNA gene. The levels of systemic inflammatory cytokines in both groups were assessed using enzyme-linked immunosorbent assays (ELISA). RESULTS: The loads of Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella intermedia were significantly more abundant in the AD compared to the control group (p < 0.05). Although Aggregatibacter actinomycetemcomitans and Streptococcus mutans were relatively frequent in the AD group, no significance difference was observed in their copy number between two groups. Although the concentrations of IL-1, IL-6, and TNF-α were higher in the AD group, there was a significant difference in their levels between the two groups (p < 0.05). Finally, there was a significant relationship between increased number of pathogenic bacteria in oral microbiome and higher concentration of cytokines in patient's blood. CONCLUSION: Our knowledge of oral microbiome and its exact association with AD is rather limited; our study showed a significant association between changes in oral microbiome bacteria, increased inflammatory cytokines, and AD.

Investigation into antibacterial and wound healing properties of platelets lysate against Acinetobacter baumannii and Klebsiella pneumoniae burn wound infections.

BACKGROUND AND AIM: Treatment of burn wound infections has become a global challenge due to the spread of multidrug-resistant bacteria; therefore, the development of new treatment options for the mentioned infections is essential. Platelets have drawn much attention for this purpose because they are a safe and cost-effective source of different antimicrobial peptides and growth factors. The present study evaluated antibacterial effects and wound healing properties of Platelet-derived Biomaterial (PdB) against Acinetobacter baumannii and Klebsiella pneumoniae burn wound infections. METHODS: PdB was prepared through the freezing and thawing process and then, in vitro antibacterial effect was determined by disk diffusion and broth microdilution methods. Afterward, burn wound was inflicted on 56 rats, infected with both bacteria, and topical administration was performed to evaluate antibacterial effects and wound healing properties of PdB. RESULTS: In vitro results showed that PdB inhibited the growth of A. baumannii in the highest dose (0.5), while we did not detect any inhibitory effects against K. pneumoniae. By contrast, PdB significantly inhibited the growth of bacteria in treated animal wounds compared to the control groups (P value < 0.05). Macroscopic assessments pointed to the significant enhancement of wound closure in the treated animals. In addition, histopathological examination demonstrated that treatment of rats with PdB led to a considerable increase in re-epithelialization and attenuated the formation of granulation tissue (P value < 0.05). CONCLUSION: The use of topical PdB is an attractive strategy for treating A. baumannii and K. pneumoniae burn wound infections because it inhibits bacterial growth and promotes wound healing properties.

Solid lipid nanoparticles and their application in the treatment of bacterial infectious diseases.

Nano pharmacology is considered an effective, safe, and applicable approach for drug delivery applications. Solid lipid nanoparticle (SLNs) colloids contain biocompatible lipids which are capable of encapsulating and maintaining hydrophilic or hydrophobic drugs in the solid matrix followed by releasing the drug in a sustained manner in the target site. SLNs have more promising potential than other drug delivery systems for various purposes. Nowadays, the SLNs are used as a carrier for antibiotics, chemotherapeutic drugs, nucleic acids, herbal compounds, etc. The SLNs have been widely applied in biomedicine because of their non-toxicity, biocompatibility, and simple production procedures. In this review, the complications related to the optimization, preparation process, routes of transplantation, uptake and delivery system, and release of the loaded drug along with the advantages of SLNs as therapeutic agents were discussed.

PLGA-Based Nanoplatforms in Drug Delivery for Inhibition and Destruction of Microbial Biofilm.

The biofilm community of microorganisms has been identified as the dominant mode of microbial growth in nature and a common characteristic of different microorganisms such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. The biofilm structure helps in the protection from environmental threats including host immune system and antimicrobial agents. Thus, the biofilm community has led to a higher prevalence of multidrug-resistant (MDR) strains in recent years. In this regard, the use of a new class of antibiotics, natural compounds, and anti-biofilm enzymes has been considered for the destruction of the microbial biofilm. However, different drawbacks such as low penetration, high susceptibility to degradation, instability, and poor solubility in aqueous solutions limit the use of anti-biofilm agents (ABAs) in a clinical setting. As such, recent studies have been using poly lactic-co-glycolic acid (PLGA)-based nanoplatforms (PLGA NPFs) for delivery of ABAs that have reported promising results. These particles, due to proper drug loading and release kinetics, could suppress microbial attachment, colonization, and biofilm formation for a long time. Additionally, PLGA NPFs, because of the high drug-loading efficiencies, hydrophilic surface, negative charge, and electrostatic interaction, lead to effective penetration of antibiotics to the deeper layer of the biofilm, thereby eliminating the microbial biofilm. Thus, PLGA NPFs could be considered as a potential candidate for coating catheters and other medical material surfaces for inhibition and destruction of the microbial biofilm. However, the exact interaction of PLGA NPFs and the microbial biofilm should be evaluated in animal studies. Additionally, a future goal will be to develop PLGA formulations as systems that can be used for the treatment of the MDR microbial biofilm, since the exact interactions of PLGA NPFs and these biofilm structures are not elucidated. In the present review article, we have discussed various aspects of PLGA usage for inhibition and destruction of the microbial biofilm along with different methods and procedures that have been used for improving PLGA NPF efficacy against the microbial biofilm.

The application of selenium nanoparticles for enhancing the efficacy of photodynamic inactivation of planktonic communities and the biofilm of Streptococcus mutans.

OBJECTIVE: Streptococcus mutans is one of the principal causative agents of dental caries (tooth decay) found in the oral cavity. Therefore, this study investigates whether selenium nanoparticles (SeNPs) enhance the efficacy of photodynamic therapy (PDT) against both planktonic communities and the one-day-old biofilm of S. mutans. In this study, the planktonic and 24-h biofilm of S. mutans have been prepared in 96-cell microplates. These forms were treated by methylene blue (MB) and SeNPs and then were exposed to light-emitting diode (LED) lighting. Finally, the results have been reported as CFU/ml. RESULTS: The outcomes demonstrated that MB-induced PDT and SeNPs significantly reduced the number of planktonic bacteria (P-value < 0.001). The comparison between the treated and untreated groups showed that combining therapy with SeNPs and PDT remarkably decreased colony-forming units of one-day-old S. mutans biofilm (P-value < 0.05). The findings revealed that PDT modified by SeNPs had a high potential to destroy S. mutans biofilm. This combination therapy showed promising results to overcome oral infection in dental science.

Antimicrobial effects of selenium nanoparticles in combination with photodynamic therapy against Enterococcus faecalis biofilm.

BACKGROUND: Selenium Nanoparticles (SeNPs) were reported as an agent that may enhance the effectiveness of Photodynamic Antimicrobial Chemotherapy (PACT). This in vitro study evaluates the effect of SeNPs on the efficacy of Methylene Blue (MB)-induced PACT against the biofilm formated in 96-well plates and the dentine tubule biofilm of Enterococcus faecalis. METHODS: Chitosan coated SeNPs were synthesized using chemical reduction method and were characterized by Transmission Electron Microscope (TEM) and Dynamic Light Scattering (DLS). Twenty-four-hour biofilms of E. faecalis were developed on 96-well plates and treated with SeNPs, MB, and Light-Emitting Diode (LED). Also, three-week biofilms of E. faecalis were formed on 67 specimens of dentinal tubules, and the antibacterial effects of MB+SeNPs on these biofilms were studied. RESULTS: The average hydrodynamic diameter of SeNPs was 80/3 nm according to DLS measurement. The combined use of MB and SeNPs significantly reduced Colony-Forming Units (CFUs) of one-day-old E. faecalis biofilms in comparison with the control group (P value < 0.05). Besides, combination therapy had the most antibacterial effect on root canal E. faecalis biofilms at both 200 and 400 µm depths of dentine tubules (P value < 0.001). Of note, about 50% of human fibroblast cells survived at a concentration of 128 µg/ml of SeNPs, compared to the control group. CONCLUSION: The results demonstrated that the photodynamic therapy modified by SeNPs could be an effective disinfection alternative to the destruction of E. faecalis biofilms and root canal treatment.

Wound healing properties and antimicrobial activity of platelet-derived biomaterials.

We analyzed the potential antibacterial effects of two different PdB against methicillin-resistant S. aureus and P. aeruginosa. The third-degree burn wound healing effects of PdB was also studied. Blood samples were obtained from 10 healthy volunteers and biological assays of the PdB were performed and the antimicrobial activity against MRSA and P. aeruginosa was determined using disk diffusion (DD), broth microdilution (BMD), and time-kill assay methods. 48 Wistar albino rats were burned and infected with MRSA. Two groups were injected PdB, the control groups were treated with plasma and received no treatment respectively. In the next step, the rats were euthanized and skin biopsies were collected and histopathologic changes were examined. The results of DD and BMD showed that both PdB performed very well on MRSA, whereas P. aeruginosa was only inhibited by F-PdB and was less susceptible than MRSA to PdBs. The time-kill assay also showed that F-PdB has an antibacterial effect at 4 hours for two strains. Histopathological studies showed that the treated groups had less inflammatory cells and necrotic tissues. Our data suggest that PdB may possess a clinical utility as a novel topical antimicrobial and wound healing agent for infected burn wounds.