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Introduction: Tribulus was traditionally used as a diuretic, mild laxative, urolithiasis, dysurca for treatment of urinary tract problems including stones, cystitis and infections, particularly Gonohrea. Antimicrobial cffects of methanol extract of Tribulus fruit on few gram positive and negative bacteria, the causative agents of some bacterial infections was evaluated and then compared with some in use antibiotics for these infections.
Materials and Methods: In this research as an experimental study. 40 gr powder of Tribulus fruit was dissolved in 100 ml pure methanol as a solvent with cold maseration method, the suspension was filtered after 5 day. The filtered suspension were concentrated with rotary evaporator apparatus in vaccum and was then dilluted with methanol to yield different concentrations. The antimicrobial activity of the extract and antibiotical were examined with disc diffusion and tube dilution standard methods to measure the diameter of inhibition zones, minimal inhibitory concentration and minimal bacterial concentration.
Results: The results were shown that the antimicrobial effect of the methanol extract of Tribulus fruit on ATCC strains of Streptococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas acroginosa had bactriostatic effect with the concentration of 400, 200, 100, 100 ug/ml in order. The comparison of urinary tract infections, including Oxacilin, Ciprofloxacin, Penicilin G, Gentamycin, Cotrimoxazole, Nalidixic acid and Nitroforantoin were shown that Tribulus fruit extract in concentration used in this research had a similar or even better effect than some antibiotics on some of the bacteria used in this evaluation.
Conclusion: The Tribulus fruit extract has an efficient bactriostatic and bactricidal activity of few gram positive and negative bacteria, the causative agents of some bacterial infections and these cffects are comparable to those antibiotics in usc for treatment of these infections. Tribulus fruit extract could be suggested for treatment of these infections after the pharmacological and clinical complementary studies.

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Introduction: Extracts of leaves from Camellia sinensis L contains polyphenolic components with antimicrobial activity. In this investigation biofilm inhibitory effects of black and green tea extracts were defined for five members of enterobacteriacea family including: Enteropathogenic Escherichia coli, Shigella flexneri, Proteus mirabilis, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium. Because tea is the most widely drunk beverage in Iran, therefore investigation of its effects on enterobacterial biofilm formation and colonization is very important. Materials and Methods: In this experimental study after extraction of samples with Soxhlet extractor in water/ methanol solution, further extraction took place in Ethyl acetate phase. The extracts preserved in 4oC refrigerator after sterilization by 0.44 µ filters. Well diffusion (Kirby Bauer) and broth dilution methods were used for evaluation of minimum inhibitory concentration of biofilm formation in black and green tea extracts treated cultures. Evaluation of biofilm formation was assayed by observation of colony forming unit of cultured bacteria per milliliter by sampling from Erlenmeyer flask wall scratching onto Tripticase soy agar medium and comparing the results with controls. Analysis of data was done using analysis of variance. Results: Biofilm inhibitory effects of black tea were greater than green tea. The concentration of 4.5 mg/ml of black tea and 5mg/ml of green tea had bactericidal effects against examined bacteria. On Mueller Hinton agar, Proteus mirabilis was more sensitive to black tea EPEC was more sensitive to green tea and Klebsiella pneumoniae showed more resistance to both extracts. Conclusion: Due to the fact that gastrointestinal tract is directly affected with consumed beverage, the high concentration of tea entered in lumen can reduce the number of enterobacteriaceae and can reduce their carcinogenic amine products. Thus it plays an important role in inhibition of gastrointestinal lymphoma and colon carcinoma. Also application of tea polyphenols as a food preservative can be useful.

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Background: Microbial infections are important challenges to health, and health care officials have major difficulties dealing with them especially regarding their antibiotic resistance. The main aim of this study was to evaluate drug synergistic and anti-bacterial effects of cuminum cyminum essential oil on some pathogen bacteria. Materials and Methods: Cuminum cyminum essential oil was extracted from its fruit. For evaluation of antibacterial effects of the essential oil, disc diffusion method through the measurement of the inhibitory zone diameter and micro-broth dilution for determining the minimum inhibitory concentration (MIC) on several standard bacteria were used. In evaluation of the synergistic and antagonistic effects, standard bacteria were cultured in the media containing essential oil, and antibiotic discs were, then, placed on it. Results: According to the results of disc diffusion test in Agar, cuminum cyminum essential oil, with a 44 mm inhibition zone, had the greatest antibacterial activity against bacillus cereus. It had the greatest positive co-action with gentamicin (10 µg) on escherichia coli. Conclusion: The results of this study indicate that cuminum cyminum essential oil alone or in combination with antimicrobial agents may be useful in treatment of bacterial infections. Additionally, this component can enhance the effect of some antibiotics this implies its application, especially in drug resistance cases.

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Background: Bacterial vaginosis is one of the most common infections in women at reproductive age. Although metronidazole is recommended as the first-line treatment, it has various side effects which make it difficult for patients to continue the treatment. Thus, the need is felt for finding a medication with fewer side effects. The aim of this study is to compare the effects of micosin vaginal cream (made of garlic) and metronidazole vaginal gel on treatment of patients with bacterial vaginosis. Materials and Methods: This study was a clinical trial which was conducted on 100 married women, aged 18-44, whose infection with bacterial vaginosis was diagnosed through clinical Amsel criteria. The participants were randomly divided into two groups of 50 persons each: Micosin vaginal cream and metronidazole vaginal gel. Patients identified with tricamona or candidiadis infections were excluded from the study. Treatment period in each group lasted for seven days. Clinical Amsel criteria and patient complaints were again checked 2 to 7 days after completion of the treatment period, and the side-effects were registered. Results: Following the treatment with micosin vaginal cream and metronidazole vaginal gel, patient complaints and clinical Amsel criteria showed a significant decrease (p<0.05), in a way that clinical recovery rates in micosin and metronidazole groups were 80% and 70%, respectively. Conclusion: Micosin vaginal cream seems to be an appropriate alternative for metronidazole vaginal gel in treatment of bacterial vaginosis.

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Background: Due to problems caused by traditional dressings, scientists have long been in search for producing alternative cellulose. Unique characteristics of bacterial cellulose synthesized by acetobacter xylinum, due to its nanostructure cellulose, resulted in attempts to devise an ideal dressing with this cellulose. The main aim of this study is to evaluate the effect of impregnated bacterial cellulose on staphylococcus aureus culture. Materials and Methods: In this descriptive-analytical study, cellulose disks synthesized by bacterial cellulose and cellulose blank disks (without antibiotic) were placed in 3.3% ciprofloxacin hydrochloride. These disks were, then, together with ciprofloxacin standard, control cellulose, and cellulose blank disks, placed on the cultured media of staphylococcus aureus. After 24 hours, the results were obtained through the measurement of growth inhibition zone. Determining the amount of antibiotic absorbed into bacterial cellulose can be done through the comparison of the effects of cellulose disks containing different concentrations of ciprofloxacin hydrochloride and ciprofloxacin standard disks. Results: Both cellulose and blank disks created a growth inhibition zone in staphylococcus aureus media, whereas the growth inhibition zone of cellulose and cellulose blank disks (negative control) were insignificant. Conclusion: Noticing the unique characteristics of bacterial cellulose as a dressing and its proven ability in absorption and release of ciprofloxacin hydrochloride, the prospects are seen for production of antibiotics containing dressings of this microbial product in future.

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Background: Bacterial cellulose synthesized by acetobacter xylinum is a harmless microbial product with unique characteristics as an ideal dress that many studies have been done on. The aim of this study was to consider the capability of this product in absorption and release of tetracycline hydrochloride. Indication of this capability can pave the way for supplying a new dressing containing antibiotic from bacterial cellulose. Materials and Methods: In this experimental study, cellulose sheet was initially impregnated on aqueous solution of tetracycline hydrochloride. Then the release process was considered in diluted water and normal saline. Ultra violet spectrophotometry method was applied to the detection of the antibiotic during absorption and release processes. Results: The results of data analysis demonstrated that bacterial cellulose has a great potential in absorption of tetracycline hydrochloride and can release it in a wet environment. Conclusion: Considering the advantages of bacterial cellulose over traditional dressings, the results of this study can provide the ground for further research on supplying an ideal dressing containing antibiotic from this microbial product.

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Background: Brucellosis is caused by brucella which is a facultative intracellular pathogen invading both professional and nonprofessional phagosytic cells. Eucalyptus globulus is one of the most widely used medicinal plants in folk medicine throughout the world. The aim of this study was to evaluate the antibacterial effects of Eucalyptus globulus extracts on intramacrophage Brucella melitensis 16M. Materials and Methods: In this experimental study, after preparing aquatic, ethanolic, and acetonic extracts of Eucalyptus globules, the effect of the extracts on intramacrophge survival of B. melitensis 16M obtained from cell culture of Balb/c mice peritoneal macrophages was studied. In order to do this, after lysis of macrophages, through preparation of serial dilutions and culture on Mueller Hinton agar medium, the number of colonies grown was counted. Results: The maximum antimicrobial activity of Eucalyptus globulus extracts on intramacrophage B. melitensis 16 M were in 1:40 dilution (21.62 mg/ml) of the aquatic extract, 1: 640 dilution (1.26 mg/ml) of the ethanolic extract, and 1:320 dilution (2.59 mg/ml) of the acetonic extract after 24h. Conclusion: Aquatic, acetonic, and ethanolic extracts of Eucalyptus globulus possess antimicrobial properties against intramacrophage B. melitensis 16M and ethanolic extract has the most effective antimicrobial activity on intramacrophage Brucella melitensis therefore, these extracts can be useful in treatment of brucellosis.

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Background: Differentiation of M. tuberculosis complex organisms were assigned to one of three genotypic groups based on the combinations of polymorphisms at katG codon 463 and gyrA codon 95. Early identification of strains belonging to any particular group is very important. This study was planned to identify major genetic groups of clinically isolated Mycobacterium tuberculosis. Materials and Methods: In this cross sectional study 33 sputum samples were collected from tuberculosis patients of the Markazi province. DNA purification from isolated samples was performed by Chelex 100. Identification of isolates was confirmed by detection of katG gene and the mutation in KatG463 by using PCR method and RFLP respectively. Finally 620-bp of katG gene and 194-bp of gyrA gene purified from PCR product were sequenced. Results: Amplification of 620-bp fragment of katG gene was a good way to confirm the detection of bacteria as a molecular approach. Results of sequencing codon GyrA95 in combination by results of PCR-RFLP determined type of the major genetic group (MGG). Therefore it showed that among the 33 Mycobacterium tuberculosis isolates 12 samples were MGG 1, 15 Samples were MGG2 and 6 samples were MGG 3. Results revealed that MGG 2 was dominant form of M. tuberculosis strains of Markazi province by frequency of 45.5%. Conclusion: Based on the results of this study MGG2 occurrence was more frequent among clinical strains in Markazi province that its accordance with susceptibility of these strains to conventional antibiotics is notable. In this study, three applicable benefits from the test as: MGG typing, molecular detection of M. tuberculosis and bacterial resistance to Isoniazid were proven.

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Background: The most important pathogen in nosocomial infections are microorganisms in the patient's body. 90 percent of nosocomial infections caused by bacteria. Medlar is an medicinal plant that its therapeutic effects has historically been emphasized. The aim of this study was to evaluate the antibacterial effect of methanolic and ethanolic leaf extract of medlar against bacteria isolated from hospital environment.

Materials and Methods: In this experimental study, the Nosocomial bacteria were obtained from Shahid Mostafa Khomeini hospital, Ilam, Iran. Soxhlet extraction method was used for medlar leaf extract. Disk diffusion method was used to study the effect of antimicrobial and broth microdilution method were used to determine the minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC).

Results: Two strains of Pseudomonas aeruginosa, three strain of Staphylococcus aureus and five strains of Escherichia coli were isolated from hospital. The results showed that the methanolic extract of Medlar leaf inhibited the growth of all strains of pseudomonas aeruginosa and four strain of Staphylococcus aureus and also inhibits the growth of all strains of Escherichia coli strains except E4 strain. The maximum antimicrobial activity was against E2 strain that zone diameter around it was 19/67 Millimeters. Quantities of minimum inhibitory concentration for all three strains P1, P2 and P3 and E2, E3, E5, S1, S2 and S3 strains was equals with 125 mg/ml.

Conclusion: Medlar leaf methanolic extract possesses significant antibacterial activity against bacteria causing nosocomial infections and so this extract can be considered in the control of infectious diseases.

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Background: According to the studies, Iran’s per capita antibiotic consumption is remarkable. Since the emergence of Antibiotic Resistant Organisms (AROs) is considered a global problem in the community and hospitals, this study aimed to investigate the pattern of antibiotic resistance in Gram-negative bacteria isolated from patients in an academic and a non-academic hospital in Arak, Iran.

Materials and Methods: This descriptive cross-sectional study included all specimens referred to the microbiology laboratory at Amir Al-Momenin Hospital (academic hospital) and Imam Khomeini Hospital (non-academic hospital) in a one-year period from June 2012 to June 2013. The susceptibility of the isolated Gram-negative bacteria against the important antibiotics used in clinical practice was determined using the disk diffusion method.

Results: A total of 846 specimens were collected from patients in the two hospitals where 520 (61.5%) were Gram-negative bacteria, of which 63.3% were E. coli. The prevalence of Gram-negative organisms in the academic and the non-academic hospital was measured 79.8% and 20.2%, respectively (p=0.097). It was also determined that there is a significant difference between the two hospitals in the prevalence of ESBL (Extended-Spectrum Beta-Lactamase) Gram-negative bacteria (p=0.003).

Conclusion: There was a significant difference between the two hospitals in the prevalence of ESBL Gram-negative bacteria. Therefore, conducting regional surveillance programs to examine the patterns of antibiotic resistance is recommended.

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Background: Biosurfactants are amphiphilic biological compounds produced extracellularly by a variety of microorganisms. Because their use in various industries are of a particular importance. The aim of this study was to identify a strain of bacteria of the genus Bacillus Cereus biosurfactant producers and investigate the antibacterial effects of biosurfactant produced.

Materials and Methods: In this study, different samples of oil, water and soil contaminated with oil were prepared. Hemolytic activities, emulsification and measurement of surface tension were used and selected strains were identified by biochemical tests. The nature and effect of antibacterial biosurfactant were evaluated for strain selection.

Results: In this study, eighty eight bacterial strains were isolated. Among them, 24 strains were hemolytic activity. Among them, 14 strains have emulsification activity more than 70% and finally from among them four strains were able to convey to the surface tension of less than 40 mN/m. On the basis of biochemical tests, a strain selective in this study as B. cereus 43 strain, were identification and selection. The results of investigating the nature biosurfactant determined that the type of lipopeptide. Also, the produced biosurfactant has antibacterial activity against six bacterial infectious. The most sensitive and the most resistant bacteria than the impact of biosurfactant extract, of S. aureus PTCC1112 and of the Proteus mirabilis ATCC 2601 respectively. Also, the results of MIC, MBC showed that MIC extract were effective in a dilution of 63 mg/ml on S. aureus PTCC1112 and S.epidermidis ATCC 2405 and the MBC extract had the greatest effect in a dilution of 125mg/ml on Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa PTCC 1074 respectively.

Conclusion: Bacillus Cereus 43 had high potential in reducing the surface tension and biosurfactant extracted had high antibacterial effects. Therefore, Frequency of potential has for applications of biotechnology and the environment.

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Nontuberculous mycobacteria (NTM), also known as atypical mycobacteria or mycobacteria other than tuberculosis are environmental organisms that are normally found in soil and water. Many of the mycobacterial species that have been described in the past decade are involved in human diseases, especially in patients with AIDS and immunocompromised HIV-negative patients. In this study, pathogenicity and clinical significance of new species of mycobacteria were evaluated. A total of 63 new species of non-tuberculosis mycobacteria, recognized in the past ten years (2003-2013), were classified in different Runyon groups. Approximately, 40 isolates were reported to infect human. Of these, 27 (67.5%) were non-chromogenic and 13 (32.5%) were scotochromogenic. The majority of the 40 isolates belong to the slow grower group. Photochromogenic species were not pathogenic to human. The most frequent infections included respiratory infections in elderly people and cervical lymphadenitis in children caused by Mycobacterium kyorinense and Mycobacterium mantenii, respectively. NTM also causes disseminated infections, the most frequent agents of which are M. boenickei, M. houstonense, M. neworleansense, and M. brisbanense in immunocompromised HIV-negative persons. Some of the NTMs, such as Mycobacterium riyadhense, are considered the primary pathogens for human. Considering the progressive spread of HIV co-infected mycobacteria in recent years, accurate identification of these agents’ pathogenicity, drug resistance, and appropriate treatment in epidemic regions, such as Iran, is essential.

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Background: This study aimed to examine the antibacterial effect of Polyamidoamine-G4 dendrimer on Escherichia coli, Enterobacter cloacae, Bacillus subtilis and Staphylococcus aureus.

Materials and Methods: In this experimental study, the antibacterial effects of Polyamidoamine-G4 dendrimer were studied by disc diffusion and micro-dilution method. Different concentrations of Polyamidoamine-G4 inoculated onto blank disks and were placed in Mueller-Hinton agar media. Zone of inhibition was investigated by bacterial inoculation according to the McFarland standard 0.5. Minimum inhibitory concentration and minimum bactericidal concentration of Polyamidoamine-G4 dendrimer were determined by micro-dilution method in nutrient broth culture.

Results: Zone of inhibition in concentration 500 &mug/ml of Polyamidoamine-G4 dendrimers for Escherichia coli, Enterobacter cloacae, Bacillus subtilis and Staphylococcus aureus were 14, 0, 35 and 29mm, respectively. Concerning the Zone of inhibition in gram negative bacteria with gram positive ones was p<0.05 and had significant difference. The minimum inhibitory concentration of Polyamidoamine-G4 dendrimer for Escherichia coli, Bacillus subtilis and Staphylococcus aureus were 1250, 2.5, and 1 &mug/ml, respectively. The minimum bactericidal concentration of Polyamidoamine-G4 dendrimer belonged to Escherichia coli, Bacillus subtilis and Staphylococcus aureus were 2500, 5 and 5 &mug/ml, respectively. Polyamidoamine-G4 dendrimer had not bacteriostatic and bactericidal effects on Enterobacter cloacae.

Conclusion: According to the results, Polyamidoamine-G4 dendrimer can eliminate Escherichia coli, Staphylococcus aureus and Bacillus subtilis effectively. It is suggested in the rest of this study that the probable toxicity of nanostructured compounds examined in drinking water and, economic studies is done for synthesis and their applications in case of prevention of using.

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Background:  Ferula assa-foetida is one of the common medicines that was used as antiseptic with a view to traditional uses, it can be used as a safe and effective drug to treat diseases particularly resistant bacterial infections. This study aims to product gelatin nano- capsules containing Ferula assa-foetida essential oil and investigate their antioxidant and antibacterial activities.

Materials and Methods: This experimental study was performed on gelatin nano-capsules containing Ferula assa-foetida essential oil (FAO) (2, 4, 6 and 8% w/w), glycerol (25% w/w) as plasticizer and glutaraldehyde as cross-linker. The morphology, antioxidant and antibacterial activities and operation of the nano-capsules were assessed according to American Standards by Scanning Electron Microscopy, ABTS, and microbiological tests.

Results: Gelatin nano-capsules exhibited low antioxidant and antibacterial activities while gelatin nano-capsules incorporated with FAO exhibited excellent antioxidant and antibacterial. The highest rates of these effects were seen merged with 8% of FAO.

Conclusion: Gelatin nano-capsules merged with FAO have excellent physical form, as well as they are an appropriate antioxidant and antibacterial that have been considered to produce antoxidant and antibacterial drugs.

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        Background: Dendrimers are a subset of branched structures that have certain structural order. The aim of this study was to investigate the performance of Polypropylenimine-G2 (PPI-G2) dendrimers in removal of Escherichia coli, Proteus mirabilis, Bacillus subtilis and Staphylococcus aureus from aqueous solution .

        Materials and Methods: In this experimental study , initially dilution of 10³ CFU/ml was prepared from each strain of bacteria . Then , different concentrations of dendrimers (0.5, 5, 50 and 500 µg/ml) was added to water . In order to determine the efficiency of dendrimers in removal of bacteria, samples were taken at different times (0, 10, 20, 30, 40, 50 and 60 min) and were cultured on nutrient agar medium . Samples were incubated for 24 hours at 37 ° C and then the number of colonies was counted .

       Results: By the increasment of dendrimer concentration and contact time , the number of bacteria in aqueous solution decreased. In times of 40 , 50 and 60 minutes, and the concentrations of 50 and 500 µg/ml, all kinds of bacteria in aqueous solution were removed . 0.5 µg/ml of dendrimer concentration had not effect in reducing the number of Escherichia coli and Proteus mirabilis . The effect of dendrimer on gram-negative bacteria was weaker than gram-positive bacteria.

       Conclusion: Results of this study indicated that PP I -G2 dendrimer is able to remove Escherichia coli , Proteus mirabilis , Staphylococcus aureus and Bacillus subtilis in aqueous solution. However, using dendrimers can be considered as a new approach for drinking water disinfection but it requires further wide range studies.

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Background: Lamiaceae family has about 200 genuses and 4000 species. The majority of species of the family have essence that was used for nutritional, cosmetic and pharmaceutical industry. The aim of this study was to investigate the chemical composition of essential oil from aerial parts of Bollota platyloma  and antibacterial activity of it.

Materials and Methods: In this experimental study, study Ballota platyloma, belonging to lamiaceae family and entomic of iran, was collected from Versk region in Mazandaran provinc. Essential oil from aerial parts was obtained by hydro distillation method by using Clevenger apparatus. GC/MS analysis of essential oil was carried out to identify major volatile constituents. Extraction was prepared by maceration method. Antibacterial activity of methanolic extracts against Pseudomonas aeruginosa, Bacillus subtilis, Stapylococcus aureus, Escherichia coli was investigated by disc diffusion method and minimal inhibitory concentration(MIC) method.

Results: Results showed that GC/MS analysis of the essential oil confirms the presence of 24 constituents in Ballota platyloma. The main constituents were Hexadecanoic Acid (40.03%), Germacrene D (26.6%) and Beta Caryophylene (4.76%). The results indicated that methanolic extract of Ballota platyloma possessed antibacterial activity. Among the aforementioned bacteria, the highest antibacterial activity was seen against S. aureus and the lowest activity against P. aeruginosa.

Conclusion: The findings of the present study showed that the major component of oil essential was germacrene-D and methanolic extract from the aerial parts of Ballota platyloma Rech. f. possess anti-bacterial effects. Thus, in order to find the underlying mechanism of this activity, further research should be carried out.

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Background: Dendrimers are macromolecules with regular three-dimensional structure that have many branches. The aim of this study was to investigate the fficiency of Nano Polyamidoamine–G5 (NPAMAM-G5) dendrimers in removal of Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa, Proteus mirabilis and Staphylococcus aureus from aqueous solution.

Materials and Methods: In this experimental study, initially, dilution of 10³ CFU/ml was prepared from each strain of bacteria. Then, different concentrations of dendrimers (0.025, 0.25, 2.5 and 25 µg/ml) in the ambient temperature (23-25°C) was added to water. In order to determine the efficiency of dendrimers in removal of bacteria, samples were taken at different times (0, 10, 20, 30, 50 and 60 min) and were cultured on nutrient agar medium. Samples were incubated for 24 hours at 37 ° C and then the number of colonies was counted.

Results: There is a direct relation between antibacterial properties of dendrimers in aqueous solution and increasing the dendrimer concentration and contact time. At a concentration of 25 μg/ml and 60 minutes, all kinds of bacteria except Staphylococcus aureus, and at 30 minutes, E. coli and Klebsiella bacteria, were removed by 100% The concentration of 2.5 μg/ml at 60 minutes of  bacteria, Escherichia coli, Klebsiella and Proteus mirabilis, 100% Were removed. All concentrations of dendrimer at different times were reduced bacteria.

Conclusion: Results of this study indicated that NPAMAM–G5 dendrimer is able to remove Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa, Proteus mirabilis and Staphylococcus aureus from aqueous solution.

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Background and Aim: The widespread use of antibiotics has been led to increased emergence of antibiotic resistant bacteria and high mortality and morbidity rates due to infectious diseases. Pseudomonas aeruginosa is one of the most important causes of nosocomial infections, which shows high resistance to a wide range of antibiotics. So, finding new and effective antimicrobial compounds in order to overcome antibiotic resistant infectious diseases is so critical. Screening of native actinobacteria can be an effective strategy to find novel antimicrobial compounds. The aim of current study was isolation, screening and identification of rare actinobacteria to find the strains which produce antimicrobial compounds against P. aeruginosa. Material and Methods: Thirty samples of water and sediments were collected from Persian Gulf and Oman Sea and used for isolation of actinobacterial strains. After isolation of actinobacteria, their metabolites were extracted and their anti-P. aeruginosa activities were investigated. Minimum inhibitory concentration (MIC) of the most efficient extract was determined using broth microdilution method. Finally, the most efficient strain was identified. Ethical Considerations: In this study, all principles of biosafety and bioethics have been considered. Findngs: Fifty actinobacteria were isolated from water and sediments. Five isolates had considerable antimicrobial activity. MIC value of the most efficient extract against P. aeruginosa was 100 µg/ml. Molecular analysis of 16SrRNA showed that the most effective fermentation broth extract belongs to Micromonospora and has 99.8% similarity to M. chalcea. Conclusion: The current study revealed that the water of southern Iran and their sediments are promising sources of potent rare Actinobacteria in the production of antimicrobial compounds against P. aeruginosa.