فهرست مطالب sarvenaz falsafi

Pseudomonas aeruginosa is one of the most important causes of infection in medicine, which in recent years is known as an antibiotic resistant bacterium. One of the antibiotic resistance strategies of this bacterium is algD and PpyR genes expression for biofilm formation. In recent years, it has been shown that using microorganisms, such as probiotics, is a method of pathogen bacterium harnessing, hence, in this study, for preventing biofilm formation of P. aeruginosa, E.coli Nissle 1917(EcN) probiotic bacterium is used, as a new treatment choice. Due to direct relationship between antibiotic resistance and biofilm formation, strains with the     highest antibiotic resistance was chosen by antibiogram test. Then, in order to determine the inhibition rate of EcN bacterium in the formation of biofilm caused by P. aeruginosa bacterium, a biofilm formation test was performed. At the end, to evaluate algD and PpyR genes expression, which were key parts of biofilm formation, in the presence of probiotic EcN bacterium, Real- time PCR method was used. Based on the results of the biofilm formation test, EcN bacterium showed a high inhibitory effect on the formation of biofilm caused by P. aeruginosa bacterium. .Also, in assessment of algD and PpyR genes expression in presence of EcN probiotic, a significant reduction in PpyR gene expression has been seen, in comparison with control group. The results of this study showed that EcN probiotic can act as a suitable new treatment option, to reduce P. aeruginosa biofilm formation.

The use of antibiotics is one of the most important ways to deal with bacterial infections. However, the improper of antibiotics and the emergence of drug resistance have compromised the effectiveness of antibiotics. Staphylococcus aureus causes a wide range of clinical diseases, and infections caused by this pathogen are increasing rapidly in the community and hospitals. Today, the treatment of this pathogen has become a challenging issue due to the emergence of multi-drug resistant strains such as MRSA (Methicillin-resistant Staphylococcus aureus). Since the antibiotic resistance of pathogens has become a global public health problem, the introduction of novel drug candidates against pathogens has become a necessity. Recently, there have been more reports on the use of OMVs as active antibacterial agents or carriers of antibiotics, which indicates the potential of OMVs in antibacterial therapy. The study aims to evaluate the effect of outer membrane vesicles of E. coli Nissle 1917 on the growth ability of Staphylococcus aureus strains.

The present study was conducted on 50 samples of Staphylococcus aureus isolated from wounds, urine, and blood. In this study, to emphasize the beneficial effect of OMVs derived from the probiotics (EcN) as a postbiotic agent, the outer membrane vesicles were extracted using the ultracentrifugation method. After confirming the presence of protein content by the SDS-PAGE method, we confirmed the structure and maintained the integrity of the vesicles during the extraction process using a FE-SEM electron microscope. Finally, to evaluate the effect of these structures on the viability of Staphylococcus aureus, we used the MTT method.

In the analysis of the protein pattern by SDS-PAGE, protein bands in the range of 15 to 100 kDa were observed. Also, the structure and integrity of outer membrane vesicles in the range of 40 to 100 nm were confirmed by an electron microscope. Finally, we saw a significant decrease in growth inhibition of all Staphylococcus aureus strains in the presence of outer membrane vesicles caused by EcN.

Considering the non-proliferative nature of OMV structures and their effects similar to probiotics, as well as, results obtained due to the significant reduction of growth inhibition of Staphylococcus aureus strains in the presence of outer membrane vesicles caused by EcN, it seems that these compounds can be a powerful tool for developing therapeutic approaches for human health and a better lifestyle.

Today, the production of green silver nanoparticles by cyanobacteria as antimicrobial agents is widely used in medical and therapeutic industries. In this study, considering that so far no study has been conducted to investigate the potency of cyanobacteria Nostoc sp. as aquatic water belonging to the freshwater of Golestan province, we decided to evaluate the potential of this strain in the biosynthesis of silver nanoparticles by performing different techniques.

After the growth and molecular identification of cyanobacteria Nostoc sp. in the BG-110 culture medium in the growth chamber, two wet biomass and boiling methods were used to produce silver nanoparticles. Then, by inoculating wet biomass at concentrations of 1, 2, and 3 mM silver nitrate and comparing color change, UV-Vis spectroscopy peaks, and measuring stability at 0, 12, 24, and 48 hours, the most efficient method of silver nanoparticle biosynthesis was selected. In addition, instrumental analysis of Raman and Fourier Transform Infrared (FTIR) spectroscopy, Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and antimicrobial disk antimicrobial properties for the best and most stable nanoparticle production method was done.

Among the two methods used in the production of silver nanoparticles, by examining the dark brown color and the strong 420 nm peak obtained from UV-Vis spectroscopy, the wet biomass method at a concentration of 1 mM at zero time had the highest adsorption compared to the boiling method. The results of FTIR showed successful production of silver nanoparticles using wet biomass of cyanobacterium Nostoc sp. at a concentration of 1 mM silver nitrate at time zero as a safe and biodegradable method, environmentally friendly, low cost, and in accordance with the principles of green chemistry. In addition, the results of FTIR showed that biosynthesized silver nanoparticles had a protein coating that plays a major role in the reduction and stability of silver nanoparticles. The DLS results showed that the nanoparticles produced were between 28 and 50 nanometers in size and the average size of silver nanoparticles was 16.1 nanometers. The results of SEM microscopy showed that the size of the produced nanoparticles was between 28 and 50 nm in terms of spherical morphology. Also, the results of the one-way analysis of variance and Tukey test showed significant inhibitory power of silver nanoparticles against Staphylococcus aureus, E. coli, and Pseudomonas aeruginosa.

Cyanobacteria Nostoc sp. can be used as a potential factor in the production of silver nanoparticles with unique properties and performance for various applications in medicine, industry, etc.

 Cyanobacteria are one of the important candidates in nanoparticle biosynthesis due to their ability to collect heavy metals. Therefore, the aim of this study was to produce and characterization of the specificity of silver nanoparticles by the native cyanobacterial strain of Nostoc spp.

 After culturing and molecular identification of cyanobacteria Nostoc spp., boiling and wet biomass methods were used to produce silver nanoparticles at different concentrations. Characterization of nanoparticle production were performed by optical spectroscopy, Ultraviolet (UV-Vis), Raman and Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM). As well as antimicrobial activity of silver nanoparticles was performed by antibiogram assay.

 The results of UV-Vis showed that the production of silver nanoparticles with the help of wet biomass at a concentration of 1 mM had a higher adsorption rate than the boiling method. The results of FTIR showed the successful production of silver nanoparticles using the wet biomass method at a concentration of 1 mM silver nitrate. In addition, the results of one-way analysis of variance and Tukey's test showed significant inhibitory power of silver nanoparticles against Staphylococcus aureus, E. coli and Pseudomonas aeruginosa.

 Nostoc spp., as a potential strain in the production of silver nanoparticles have unique properties and performance for use in microbial biotechnology.

Background &

Staphylococcus aureus is one of the human pathogens that causes a wide range of diseases such as endocarditis, blood, bone, skin and soft tissue infections (1). One of the resistant strains of this bacterium is methicillin-resistant strains of Staphylococcus aureus (MRSA), which has been reported as a serious risk by the Centers for Disease Control and Prevention. One of the pathogenic mechanisms and antibiotic resistance of this bacterium is the formation of biofilm, which causes this bacterium to bind to different surfaces (2). Biofilm-forming strains have become resistant to many antibiotics, so that biofilm-forming strains form extracellular matrices that are immune to the immune system and antibiotics. Various genes are involved in biofilm production, one of which is the icaB gene, which plays a key role in the production of poly N-acetyl glucose amine and biofilm production. The design of new antimicrobial drugs for the treatment of this bacterium is important, so finding a suitable treatment option for the treatment of infections caused by this bacterium is one of the challenges of researchers (3). Recent advances in nanotechnology have suggested alternative solutions, such as drug delivery systems, that increase drug specificity and efficiency (4). One of these drug delivery systems is nanosystems, which are composed of bilayer nonionic surfactants. Due to the importance of nanosystems, the aim of this study was to synthesize nanoparticles containing naproxen, to investigate their physicochemical properties and their antimicrobial and antifouling effects against Staphylococcus aureus strains.

Nanosomes containing naproxen were synthesized by thin layer hydration method. The confinement efficiency is indicative of the drug encapsulated in the nanosystem structure relative to the drug used. For this purpose, the nanonosomal formulation was first centrifuged at 4 ° C at 14000 g for 45 minutes. The nanosystem containing the drug precipitates and the free drug remains in the supernatant. The absorbance of the supernatant sample at 270 nm was read by a spectrophotometer and the amount of free drug was calculated from the initial value.
The Physico-chemical characteristics of prepared nanoniosome encapsulated naproxen was determined using scanning electron microscopy (SEM), Dynamic light scattering (DLS). The in vitro drug release study was done using dialysis bag (6). The Staphylococcus aureus strains were recovered from 100 clinical samples and their antibiotic resistance patterns were studied using disk diffusion method. The antibacterial activity of nanoniosome loaded naproxen and free naproxen were investigated using well diffusion and micro-dilution methods (7). The icaB biofilm gene expression analysis in S. aureus isolates which are treated with nanoniosome loaded naproxen and free naproxen were examined using Real Time PCR methods (8).
Draw diagrams and Statistical analysis was performed by GraphPad Prism software version 7 and SPSS version 23, and one-way analysis of variance was used for statistical analysis and p <0.05 was considered significant.

In this study, using different molar ratios of surfactant, cholesterol and drug, different formulations of nanosystems containing naproxen were synthesized. The optimal niosome size synthesis was measured by DLS method. The results of electron microscopy (SEM) show that the synthesized nanonosomes have a spherical structure. In this study, the dialysis bag method was used to evaluate the drug release pattern. Figure 2 shows the pattern of naproxen release from nanosystems and free naproxen over 72 hours.
Out of 100 clinical specimens, 15 specimens of Staphylococcus aureus were isolated and identified using microbiological methods. The results of antibiotic resistance profile test showed that out of 15 strains, 10 strains were methicillin resistant (MRSA).
The antibacterial activity of nanoniosome encapsulated naproxen and free naproxen showed that the MIC was reduced by 2 to 4 times. The results of the well diffusion method showed that nanoniosomes containing naproxen had more significant antimicrobial power than free naproxen, so that the diameter of the growth inhibition zone increased with increasing nanosystem concentration. Real-Time PCR was used to evaluate the effect of nanoniosoms containing naproxen and free naproxen on icaB biofilm gene expression in Staphylococcus aureus strains. Also, after treating Staphylococcus aureus strains with naproxen-containing nanosystem sub-inhibitory concentration, it was shown that the expression of icaB gene was significantly reduced compared to the 16S rRNA reference gene (p <0.05).

In this study, naproxen was encapsulated as a drug compound in the nanoniosome structure and its physical and chemical properties including size, morphology, drug enclosure percentage and drug release were studied. The results of this study showed that the synthesized nanoniosome in the optimal formulation had a spherical shape, the average size was 125.3 nm with a confinement percentage of 66.84%. Drug release results also showed that naproxen in the formulated form in nanonosomes has a much slower release pattern than free naproxen, which is a suitable feature of a drug delivery system. The results of the antimicrobial test showed that naproxen-containing nanoniosome had more significant antimicrobial effects than free naproxen compared to free naproxen, reducing the MIC by 2 to 4 times. One of the antimicrobial mechanisms of nanoniosome containing naproxen is the fusion of nanoniosome with bacterial cell membranes, which can deliberately release the drug into the cytoplasm of the cell and cause bacterial cell death (10). The results of this study showed that nanoparticles containing naproxen have more significant anti-biofilm effects than free naproxen compared to free naproxen and can significantly reduce the expression of biofilm gene (11). One of the reasons for the anti-biofilm effects of naproxen-containing nanosystems is the greater penetration of naproxen-containing nanosystems into the biofilm structure, which can cause the death of bacteria, a decrease in the number of bacteria, and the conversion of biofilms into planktonic cells (12).

Today, the widespread use of petroleum products has led to environmental pollution and has created serious problems for the health of the environment. Streptomyces make up 50% of the total population of soil actinomycetes are filamentous, gram-positive, and essentially aerobic. These bacteria are abundant in natural aquatic and terrestrial environments, are not nutritionally hardy, require only a source of carbon and nitrogen along with mineral salts, and they are able to remain in the soil as spores for a long time. The aim of the study was to clone the Streptomyces  catechol 2, 3-dioxygenase gene (C2,3) gene present in the soil in Escherichia coli bacteria in order to remove oil pollutants.

In this study, 58 samples were collected from a depth of 5 to 10 cm in different areas of the suburb of Tehran and oil contaminated areas such as the oil depot and its surroundings. After culturing, diluting and selecting suspicious Streptomyces colonies for identification, after confirmation of Streptomyces bacteria based on colony appearance, microscopic characteristics, and biochemical tests for final confirmation of molecular identification, their 16srRNA sequence was amplified and replicated, was examined. In the next step, after DNA extraction of the samples, PCR was used to amplify the C2,3 gene. The C2,3 gene was then cloned into Escherichia coli Origami by PTG19-T vector. Finally, the amount of gene expression was determined by Real Time PCR and after sequencing the phylogenetic tree was drawn.

The enzyme catechol 2, 3-dioxygenase can be extracted from limited sources such as Streptomyces, so the need for gene amplification of this enzyme is important from the bacterial sources that produce it. Therefore, in this study, this enzyme was isolated from Streptomyces. As a result of this study, we were able to find native Streptomyces that produce the enzyme catechol 2, 3-dioxygenase, and finally, the gene of this enzyme was successfully introduced into Escherichia coli Origami.

In this study, in order to create of a recombinant host with high expression capacity, it can be considered a big step towards increasing the production of this enzyme in the industry. Further investigation to find new strains producing catechol 2, 3-dioxygenase can lead to a new method of removing oil contaminants.

Hospital infections and their antibiotic resistance have become a global concern recently. One of the most prominent factors in hospital infections is Pseudomonas aeruginosa (P. aeruginosa), which can become resistant to many antibiotics due to its ability to form biofilms. Recently, scientists have tried to replace antibiotic therapy with alternative therapies such as probiotics which can reduce or eliminate the pathogenic bacteria's ability to form biofilms. Therefore, the present study revealed that some genes, such as algD
and PpyR, were involved in biofilm formation in P. aeruginosa. Furthermore, the inhibitory effect of the supernatant of lactobacillus agilis on the biofilm formation of P. aeruginosa was evaluated in the current study.

In this study, the effect of the supernatant of probiotic Lactobacillus agilis on the biofilm formation of P. aeruginosa and also the expression of two genes effective in biofilm formation (algD and PpyR) were investigated. Antibiograms were performed to detect the most resistant bacteria since there is a link between biofilm formation and antibiotic resistance. Further, the effects of probiotics on the expression of PpyR and algD genes were discussed.

Results showed that the biofilm formation of P. aeruginosa was significantly reduced in the presence of lactobacillus agilis.

According to the current study, it could be concluded that because of antibiotics resistance and their associated mechanisms, probiotics could be used as a replacement for antibiotics in many treatments.

The continuing emergence or re-emergence of vector-borne zoonotic Q fever (caused by Coxiella burnetii) and Crimean Congo hemorrhagic fever (CCHF, caused by Orthonairovirus) include indispensable extraordinary threat around the world. Low infectious dose and long-term environmental residence are major risks. Wildlife and domestic livestock act as hosts or reservoirs of the CCHF virus and ticks are carriers. The disease also poses a threat to public health services owing to its epidemic potential, high case fatality ratio (up to 40%) as well as difficulties in treatment, prevention, and control. Q fever is another zoonotic febrile disease mainly affecting workers involved in farming livestock. The causative agent of Q fever causes abortion in livestock. The pathogen is shed in large numbers in the waste of infected animals (amniotic fluids and placenta during parturition) and is transmitted by inhalation of contaminated aerosols. Vaccination is the most effective way of protecting against Q fever. The main way to prevent Q fever is to avoid contact with animals, especially while animals are giving birth, or consumption of unpasteurized milk and contaminated dairy products. Due to the increasing importation of livestock to meet the growing demand for dairy and meat products, new diseases are likely to be introduced. In our growing globalized world, where trade between countries increases, it is necessary to conduct more research on zoonotic diseases and to monitor any possible disease introduction to new areas. A continuing surveillance program and pathogen testing are important in tracking the emergence of new pathogens.

Streptomyces is an aerobic filamentous Gram-positive bacterium frequently found in various environments worldwide. Cellulases are a group of glycosyl hydrolase enzymes that are frequently produced by bacteria. Thus, the aim of this study was to detect cellulase-encoding gene (celA) in soil-living Streptomyces strains and evaluate its cloning in Escherichia coli Origami strain.

Soil samples were collected from a depth of 5-10 cm in Tehran, Iran. After identification of Streptomyces isolates by morphological and biochemical tests, genomic DNA was extracted. Polymerase chain reaction (PCR) test was employed to identify Streptomyces strains harboring the cellulase gene. The celA gene was positively transmitted to the host bacterium E. coli via a vector and cloned through the TA technique. Real-time PCR was used to measure the overexpression of this gene. ClustalX and Mega5 software were used to draw the phylogenetic tree.

Out of 12 Streptomyces isolates, 25% were found to carry the celA gene. After cloning the celA gene, the cloned strains were chosen by colony selection (blue/white). The real-time PCR test showed the expression of the celA gene in the transformed strains. Phylogenetic analysis results using the neighbor-joining assay showed that Streptomyces spp. with 81% bootstrap were located in the same clade, indicating their close relatedness.

Soil is one of the high-potential sources of the production of secondary metabolites, which could be used as a valuable source of various biological products such as cellulase.

Making cheese is simply a process of turning a liquid (milk) in-to a solid. Rennet has an important role in this process which is a complex set of enzymes where chymosin is the key component. The aim of this study was identifying the Bacillus genus with the ability of producing the enzyme. 50/75 isolates from soil of Gandom Beryan area of Kerman, Iran, determined as bacillus spp via classical and PCR methods. The presence and over production of the cltA gene (encoding chymosin) were investigated by performing cloning in Escherichia coli (E. coli) origami and functional cloning confirmed by using real-time reverse transcription –polymerase reaction (Real- time PCR) and clonal selection. The results showed functional cloning of the gene in Escherichia coli origami. Among 50 isolates of Bacillus spp, 4 isolates (8%) showed the capacity to produce the gene. Phylogenetic characterization analysis of 16S rRNA gene of the Bacillus spp determined the strains as Bacillus cereus. According to the results of this study, expression of the gene via Real-time PCR showed their ability to produce clt A gene and rennet. Although to further confirmation, a larger samples needs to be performed and additional tests are required. Due to animal rennet deficiency, determining such accessible and cheaper sources in producing rennet is important.

Pseudomonas aeruginosa is an indispensable pathogenic agent that can lead to serious infections. Antibiotic resistance is really common among bacteria, so, new therapeutic agents could be of great help in overcoming this problem. Based on previous studies, probiotic strains have a protective effect against pathogenic or Image result for opportunist bacteria opportunistic bacteria thorough various mechanisms. The main purpose of the present study was to evaluate the influence of E. coli Nissle 1917 as a probiotic strain on Pseudomonas aeruginosa strains.

In this experimental study, MIC and Disk Diffusion techniques were used to investigate the effect of E. coli Nissle 1917 on Pseudomonas aeruginosa strains. Effect of antibacterial activity of the probiotic strain was evaluated after 24h at 37°C.

The highest concentration of E. coli Nissle 1917 showed the most effective antibacterial activity against clinical and standard Pseudomonas aeruginosa strains after 24h.

Probiotic bacteria can have a positive effect on medical aspects, especially because of having access to numerous antibiotic resistance pathways. Therefore, due to lack of suitable antibiotics for several infections, probiotics could be highly helpful. Various concentrations of probiotic bacteria can also inhibit the pathogenic strain.

Women infected with human papillomavirus, especially types 16 and 18, are at risk of cervical cancer. The purpose of this study was to determine the frequency of papillomavirus-16 and -18 in women with cervical cancer using multiplex-PCR. In this experimental study, after collecting blood samples, viral DNA was extracted using a Cinaclone kit, and PCR, with specific primers, was performed to detect HPV-16 and HPV-18. PCR products were analyzed by 1% agarose gel electrophoresis. Of 60 samples, 19 were infected with HPV. The results showed that the frequency of genotype HPV-16 and HPV-18 was 8 (42.1%) and 11 (57.9%), respectively. The study showed that using PCR with specific primers for the detection of HPV-16 and HPV-18 is a convenient and accurate method. The results of this study indicate the relationship between HPV and cervical cancer.

Aim and Urinary tract infections (UTIs) are widespread health concerns which differ according to geography and regions. Bacterial Urinary tract infections associated with an enlarged antimicrobial resistant species are found in all age groups.The aim of this study was to ascertain the antimicrobial resistance pattern of strains isolated from patients with Urinary Tract Infection (UTI) and the emergence of multidrug resistant bacterial strains. Midstream urine samples were collected from 2235 patients and analyzed for isolation and identification of Multidrug Resistant (MDR) strains. The MDR strains were recognized by the Kirby Bauer method according to National Committee of Clinical Laboratory Standards. Female patients constituted 308 (62%) in the study. This result indicates that E.coli is the predominant pathogen causing UTI, followed by Klebsiella, Streptococcus viridans, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Proteus and Pseudomonas. Bacterial isolates from patients with UTI showed high levels of single and multiple antimicrobial resistances against commonly prescribed drugs. The present study confirms that bacterial resistance would be a serious problem in the country. Therefore, antimicrobial surveillance and in vitro susceptibility testing with strict adherence to antibiotic policy may facilitate to control the spreading of drug resistant microbes.

Aim and Environment is the likely source of most Non-Tuberculous mycobacteria (NTM) involved in human infections, especially pulmonary, skin, and soft tissue infections. In order to measure the prevalence of NTM in different aquatic ecosystems, we tried to standardize the isolation methods used for surface water testing since many procedures have been described previously. Cultivation of mycobacteria requires long-term incubation in rich media and inactivation of rapidly growing microorganisms whose growth impedes observation of mycobacterial colonies. 38 samples were collected from surface waters in Tehran. Water sampling was carried out in a volume of 200-100 ml. water sample was transferred immediately to the laboratory and examined. Three methods (Cetylpyridinium chlori, Petroff, Tacquet-Tison) for the isolation of mycobacteria were compared by applying them in parallel to 38 samples of surface water. Each method was defined by a particular combination of decontamination method. The efficacy of each method was determined by calculating the positivity, negativity, and contamination rates, the mean numbers of mycobacterial colonies grown and number of different mycobacterial strains isolated. The last value was determined by subjecting the isolates to PCR. Decontamination with CPC appeared to be the best decontamination method, on the one hand, it significantly decreased the level of non-target microorganisms and, on the other hand, it was significantly less lethal for the NTM strains studied. Our goal was to measure the effects of various methods known to inhibit the growth of non-target microorganisms, while we also took into consideration the inhibitory effects of these methods on the growth of NTM. We propose that CPC procedure could be used for detection of NTM in aquatic samples.