Abstract

Background and Objective: Neonatal sepsis is a remarkable factor in mortality, morbidity, neonatal and perinatal complications. Group B Streptococcus (GBS) is the primary cause of invasive disease in infants and pregnant women. This study aimed to determine the relationship between antimicrobial resistance of the bacteria colonized in the vagina and rectum of pregnant women and early neonatal infection.

Material and Methods: In this prospective study conducted on 282 pregnant women, bacterial sensitivity to ampicillin, cefazolin, erythromycin, vancomycin, gentamicin, amikacin was measured. Furthermore, the relationship between rectal and vaginal colonization of mothers and early neonatal sepsis was evaluated.

Results: Of 98 positive rectal cultures, 49 (50%) were Gram-positive cocci and 49 (50%) E.coli. of 143 positive vaginal cultures, 136 (95.1%) were Gram-positive cocci, 7 (4.9%) were E.coli and two were positive GBS.  We could find definitive neonatal sepsis. Significant correlation was found between a history of urinary tract infection and the mother's positive rectal culture (P =0. 03).

Conclusion: Clinical sepsis in neonates is correlated with positive rectal culture (P =0. 001) and the positive E.coli vaginal cultures is associated with suspected neonatal sepsis (P =0.007). Gram-positive cocci were resistance to ampicillin and gentamicin, and E.coli was resistant to ampicillin, erythromycin and vancomycin. Because of resistance to ampicillin, we recommend cefazolin due to its sensitivity to organisms and safety in pregnancy.

Keywords: Antibacterial Agents, Escherichia Coli, Gram-Positive Cocci, Newborn, Sepsis

Abstract

       Background and Objective: Antibiotics are the chemical compounds, which are produced by microorganisms, belong to a larger group of antimicrobial compounds that are used for treatment of infections caused by microorganisms.

        Material and Methods:  the isolates of four plant species, Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa were obtained using Trypticase Soy Agar. First, the purified isolates were screened from the viewpoint of their ability in producing antimicrobial metabolites against three typical microorganisms Escherichia coli, Candida albicans and Saccharomyces cerevisiae. Then, the microbial products were extracted using organic solvent ethyl acetate and their minimum suppression concentration was determined against three strains Candida albicans ATCC 10231، Staphylococcus aureus ATCC 25923 و Escherichia coli ATCC 25922.

         Results: After 4-7 days of incubation, 104 bacterial samples were isolated from isolates four plants. Out of this number, 26 isolates were antimicrobial producing metabolites by making inhibition zones against three typical microorganisms, after initial screening for production of antimicrobial compounds using agar diffusion method. Minimum inhibitory concentration of ethyl acetate extracts from target microbes were between 125-1000 µg/ml.

        Conclusion: The results showed that the bacterial extracts of phylosphere produce some compounds with antimicrobial properties.

        Keywords: Antibiotic Producing Bacteria, Fabaceae, Asteraceae

Abstract

Background and Objective: The aim of this study was to evaluate chemical composition, antibacterial and antifungal effect and antioxidant property of Salvia officinalis, Mentha piperita and Mentha Longifolia.

Material and Methods: At first, chemical analysis of essential oils was determined using GC/MS. Then the antibacterial and antifungal effect of tested essential oils on L. monocytogenes, S. aureus, S. typhimurium and E. coli and two fungal strains including A. niger and A. flavus were determined using disk diffusion agar and broth microdilution methods.  The antioxidant property of essential oils was evaluated using DPPH assay.

Results: Linalool (14.38%), l. menthone (19.03%) and δ-terpinene (21.78%) were the major components of Salvia officinalis, Mentha piperita and Mentha Longifolia, respectively. all tested essential oils had antibacterial effect on foodborne pathogens, which was comparable with tetracycline’s effect. In addition, all essences had appropriate antioxidant potential compared with BHT.

Conclusion: based on the results, Salvia officinalis, Mentha piperita and Mentha Longifolia can be introduced as appropriate natural preservatives.

Keywords: Salvia officinalis; Mentha piperita; Mentha Longifolia, Antibacterial Agents.

Abstract

      Background and Objectives: Antibiotic resistance in bacteria has actuated researchers toward evaluating many new antibacterial compounds of which are the thiazoles. In this research the inhibitory effects of novel thiazole derivatives were unraveled on Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa and Klebsiella pneumoniae and oxothiazole liver toxicity effects were assessed on mice.

       Methods: The antibacterial effect of thiazole derivatives was evaluated by measuring the halo zone with disk diffusion method and dilution procedure in microplate in order to discriminate the minimum inhibitory concentration (MIC) and the liver toxicity of oxothiazole, also, was discerned by injecting 160 mg/kg, 265 mg/ kg and 350 mg/kg doses to mice as well as scrutinizing the liver histopathology.

      Results: Derivatives utilized in experiment had no inhibitory effect on Pseudomonas aeruginosa and Klebsiella pneumoniae, though their inhibitory effect was observed on Staphylococcus aureus and Streptococcus agalactiae. For Staphylococcus aureus and Streptococcus agalactiae the diameters of growth inhibition zone were 8.9-22.3 mm and 16.1-25.6 mm, respectively and MIC of 50-200 and 25-100 µg/ml by order. Additionally, by increasing the injection dose of oxothiazole with 160 mg/ml, 265 mg/ml and 350 mg/ml doses, the hepatitis lesions and liver necrosis were observed in experimental mice.

       Discussion: The thiazole derivatives possessed more inhibitory trace on gram positive bacteria than gram negative ones. Furthermore, the likely presence of oxygen link to thiazole ring in tested compounds results in the enhancement of inhibitory potency of these substances. Besides, our results suggest that high doses of oxothiazole cause severe liver damage and rapid death less than 24 hours.

       Keywords: Thiazole derivatives, Antibacterial effects, Oxothiazole, Liver toxicity.

Abstract

      Background and Objective: Probiotics are living microorganisms that have beneficial effects on the health of digestive system. The aim of this study was to evaluate the antimicrobial ability of acidic and neutral supernatants (culture supernatant) of lactic acid bacteria against common bacterial pathogens.

       Methods: Four species of lactic acid bacteria (Lactobacillus plantarum PTCC1745, Lactobacillus PTCC1608, Lactobacillus Saki PTCC1712 and Lactobacillus Lactis PTCC1336) were obtained from the microbial collection of Iranian Research Organization for Science and Technology in Lyophilized form. The antimicrobial activity of neutral and acidic supernatants against bacterial pathogens was investigated using the Disk and Well Diffusion Agar methods.

      Results: Lactic acid bacteria showed good antimicrobial ability against six pathogenic bacteria with the highest inhibitory effect observed in Lactococcus lactis against E. coli PTCC1399 through well method with an average diameter of 14 mm inhibition zone. In this study, the well diffusion method was far more sensitive compared to the disk method and acidic supernatants showed higher antimicrobial efficiency compared to neutral types.

      Conclusion:  the Metabolites produced by lactic acid bacteria are able to inhibit the growth of pathogenic bacteria that can be an important and practical solution for the prevention and treatment of infections and ultimately improve human health.

Abstract

      Background and Objective: The spread of drug resistance in bacteria have prompted researchers to seek suitable alternative for antimicrobial drugs among various medicinal plants and nanoparticles. The aim of this study was to evaluate the effect of silver nanoparticles alone and in combination with methanol extract of Zataria multiflora on five Gram-positive and Gram-negative bacteria.

     Methods: Different concentrations of the nanoparticles and extract alone or in combination with each other were tested against the bacteria, using well diffusion method. Three concentration levels (lowest, average and highest) were prepared form the nanoparticles and the extract for the combination, and finally nine different combinations were prepared.

      Results: The extract and nanoparticles showed inhibitory effects against all the tested bacteria. The maximum diameter of growth inhibition zone in the presence of the extract and nanoparticles were observed in Streptococcus pyogenes (35.6mm) and methicillin-resistant Staphylococcus aureus (20.6mm), respectively. The maximum diameter of growth inhibition zone for the combination was measured in S. pyogenes (31mm).

      Conclusion: The combination of low concentrations of the plant extract and nanoparticles are more effective against bacteria, but the combination of their high concentrations reduce the antibacterial effects in some cases.

     

Abstract

      Background and Objective: The aim of this study was to determine the chemical composition, antibacterial and antifungal effects of Thymus vulgaris and Cuminum Cyminum essential oils against foodborne pathogens and Candida species in vitro.

      Methods: The essential oils were extracted from the aerial parts of Thymus vulgaris and dried Cuminum Cyminum seeds using a Clevenger apparatus for 3 hours. Analysis of the essential oils’ constituents was performed using gas chromatography-mass spectrophotometry. The antibacterial activity of Cuminum Cyminum essential oil and essential oil of Thymus vulgaris against Bacillus cereus, Listeria monocytogenes, Escherichia coli and Salmonella typhimurium were evaluated in agar culture medium. The minimum inhibitory concentration (MIC) of these essential oils against fungal strains of Candida albicans, C. tropicalis, C. parapsilosis and C. dubliniensis was measured.

      Results: Thymol (64.45%) and cuminaldehyde (29.02%) were the main components of the essential oil of Thymus vulgaris and Cuminum Cyminum, respectively. The largest inhibition zone diameter in the essential oils of Thymus vulgaris and Cuminum Cyminum in the agar disk diffusion method was related to B. cereus with 30 and 21 mm diameter, respectively. The largest growth inhibition zone diameter by the essential oil of Thymus vulgaris in the well diffusion method was 21 mm and against B. cereus. The MIC of essential oil of Thymus vulgaris in the microdilution method was 0.09% against all the four Candida strains. The MIC of Cuminum Cyminum essential oil against strains of C. albicans and C. tropicalis was 0.39%, while it was found as 0.19% against C. parapsilosis and C. dubliniensis.

      Conclusion: In this study, Cuminum Cyminum essential oil and essential oil of Thymus vulgaris show suitable inhibitory effects against the growth of bacteria using well and disk diffusion methods. Regarding the antifungal effects, the MIC of essential oil of Thymus vulgaris is lower than the Cuminum Cyminum essential oil, which indicates the higher antifungal activity of the essential oil of Thymus vulgaris. This study has raised the possibility of using these essential oils as suitable antimicrobial compounds and alternatives for chemical preservatives in the food industry.

Background and Objective: Considering the increasing tendency of public towards green consumption and the dangers of artificial additives, this study aimed to assess antibacterial activity of essential oils of Cinnamomum zeylanicum, Mentha piperita L., Zataria multiflora Boiss and Thymus vulgaris against three important pathogenic and spoilage bacteria (Pseudomonas fluorescens, Erwinia carotovora and Escherichia coli).

• After obtaining the essential oils from Magnolia Co., their antimicrobial activity was assessed using broth microdilution method by determining the minimum inhibitory concentration (MIC50, MIC90) and minimum bactericidal concentration (MBC). All experiments were performed in triplicate and the data were analyzed using the GraphPad software and Duncan's new multiple range test.
• All essential oils showed antimicrobial activity in a concentration-dependent manner. Increasing the concentration of essential oils from 0.01% to 4% (v/v) significantly enhancing the antibacterial activity. The statistical calculations and comparison of data showed that the essential oils of C. zeylanicum and Z. multiflora performed better compared to  the other two essential oils, due to having lower values of MIC50 (≤0.1%), MIC90 (≤0.4%) and MBC (≤1%) (P <0.05).
• Considering the high antimicrobial activity of essential oils of C. zeylanicum and Z. multiflora, they can be used as effective food additives with fewer side effects. However, further studies are being conducted on the effectiveness of essential oils on the growth of other microorganisms and their results will be published soon.
• Essential Oils, Antimicrobial, Pathogenic Bacteria, Cinnamomum Zeylanicum, Zataria Multiflora Boiss.

ABSTRACT

      Background and Objective: Glycyrrhizaglabra L. is one of the most widely used medicinal herbs in Golestan province that is known for its anti-inflammatory, carminative, antiviral, anti-infection and anti-ulcer properties in Iranian traditional medicine. This study aimed to assess the anti-bacterial and anti-oxidative activity of G. glabrafrom the Golestan province.

        Methods:  The rip root of the plant was collected in autumn 2013. The ethanolic extract of the plant was prepared by maceration method. The anti-oxidative property of the plant was assessed by total antioxidant capacity (TAC), reducing power (RP) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity assays. The anti-bacterial activity was assessed using agar-well diffusion method and the minimum inhibitory concentration (MIC) assay.

        Results: The ethanolic extract of G. glabrahad relatively high anti-oxidative activity with IC50 value of 130 µg/ml, especially in the DPPH method. The extract also exhibited high anti-bacterial activity against the following Gram-positive bacteria: Staphylococcus aureus (21.1±0.7 mm), Staphylococcus epidermidis (19.6±0.2 mm), Bacillus subtilus (19.3±0.6 mm), followed by Escherichia coli (12.1±0.8 mm), Enterococcus faecalis (13.2±0.1 mm) and Kelebsiellapneumoniae (11.5±0.4 mm) with MIC values in the range of 31 - 132 mg. mL^-1.

         Conclusion: According to results, the root extract of G.glabrais a good source of antioxidant compounds with suitable anti-bacterial activity, which can be used as natural anti-infection and anti-inflammatory agent for treatment of many diseases.

      

ABSTRACT

         Background and Objective: Hospital clothing and textiles have a great role in providing medical services to patients. Hospital services would not be possible without using these textiles. The aim of this study was to prepare non-woven polyester for use in medical textiles.

         Methods: In this study, most important expected properties of hospital clothing were created on polyester fabrics via various stages of finishing using chemicals such as calcium chloride, sodium alginate, chitosan and nanoparticles of silver nitrate and aluminum oxide. Antibacterial (activity against Staphylococcus aureus), deodorizing and wicking properties of samples were evaluated using nano-biomaterials via standard tests.

          Results: The water absorption rate of nonwoven samples that were finished with chitosan significantly improved. The results also showed favorable level of antimicrobial activity caused by silver nitrate and chitosan. In addition, deodorizing activity was observed in all samples. However, silver nitrate-finished samples had higher deodorizing activity. The capillary action of all samples reduced after completion of all finishing procedures.

          Conclusion: The results show that the use of chitosan and alginate along with nanoparticles of silver nitrate and aluminum oxide can be effective in achieving the desired properties of medical textiles.

        Keywords: Medical textiles, antibacterial substances, chitosan, silver nitrate.

Background and Objective: Nowadays, incidence of antibiotic-resistance among pathogenic bacteria has increased due to indiscriminate use of antimicrobial drugs for treatment of diseases, especially urinary tract infections. Medicinal plants are also of great importance as antibacterial agents. Therefore, the aim of this study was to determine the antibacterial effect of ethanolic extract of nettle (Urtica dioica L.) leaves using two methods of disk diffusion and well diffusion.

         Methods: Ethanolic extract of nettle leaves was prepared by the percolation method. Effect of different concentrations of the extract on Escherichia coli (PTCC1399), Staphylococcus aureus (PTCC 1431), Staphylococcus epidermidis (PTCC 1435) and Staphylococcus saprophyticus (PTCC1440) was evaluated using the disk diffusion and well diffusion methods by measuring diameter of growth inhibition zone. Gentamicin and propylene glycol were used as positive and negative control, respectively.

        Results: In both methods, especially in the well diffusion, the ethanolic extract of nettle leaves had favorable inhibitory effect on the growth of S. aureus, S. epidermidis and S. saprophyticus. In the well diffusion method, the highest rate of susceptibility to the extract (89%) was related to S. saprophyticus and S. epidermidis.

         Conclusion: The ethanolic extract of nettle leaf has good inhibitory effect on the growth of S. aureus (especially in the well diffusion method), which confirms the traditional use of this plant for the treatment of urinary tract infections.

          Keywords: Antibacterial Effect, Staphylococcus, E. Coli, Ethanolic Extract, Nettle (Urtica dioica L.).

ABSTRACT

          Background and Objective: Several studies have

shown the antimicrobial activity of lactobacilli against Salmonella enterica (serotype typhimurium). The aim of this study was to evaluate the inhibitory potential of metabolites produced by probiotic culture of Lactobacillus casei against S. typhimurium and its impact on S. typhimurium motility and biofilm formation.

         Methods: In order to evaluate the impact of the metabolites, L. casei cell-free culture supernatant (CFCS) was collected by centrifugation of L. casei secondary cultures. Effectiveness of the CFCS against Salmonella was evaluated by the well-diffusion method. In addition, in vitro effect of this treatment on motility in Swarm agar and biofilm formation by the bacteria was investigated.

         Results: Inhibition zone diameters of S. typhimurium were 0.83 and 12.1 mm at concentrations of 50 and 100 μl of Lactobacillus CFCS against the log4 of S. typhimurium, respectively. Moreover, CFCS treatment inhibited the motility and biofilm formation by Salmonella. Concentrations of 5% and 10% were determined as the minimum inhibitory concentrations for motility and biofilm formation by S. typhimurium. Furthermore, effectiveness of the CFCS against Salmonella was dose-dependent (P<0.05).

         Conclusion: L. casei CFCS is able to inhibit the growth, motility and biofilm formation in S. typhimurium.

         Keywords: Anti-Bacterial, Lactobacillus Casei Metabolites, Phenotypic Characteristics of S. typhimurium

ABSTRACT

         Background and Objective: Although antibiotics are commonly used for treatment of infectious diseases, these treatments are often associated with several problems such as unwanted side effects and resistance to antibiotics. The aim of this study was to evaluate the antibacterial effect of aqueous and alcoholic extracts of Nasturtium officinale on Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Listeria monocytogenes.

          Methods: All experiments were performed using the well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the aqueous and alcoholic extracts of N. officinale against the pathogenic bacteria studied were determined by microdilution method.

         Results: In the well diffusion method, S. aureus and L. monocytogenes were the most sensitive bacteria with MIC of 8 μg/ml, while E. coli and S. typhimurium were the most resistant bacteria to the aqueous and alcoholic extracts. In addition, the inhibitory activity of the alcoholic and aqueous extracts of N. officinale was higher against gram-positive bacteria compared to gram-negatives. The lowest MIC (6.25 μg/ml) and MBC (12.5 μg/ml) of the plant extract were against S. aureus.

          Conclusion: The aqueous and alcoholic extracts of N. officinale affect the growth of gram-positive bacteria (S. aureus and L. monocytogenes) but not the gram-negatives (S. typhimurium and E. coli). These extract could be used for treatment of infections.

        Keywords: Nasturtium Officinale, Aqueous Extract, Alcoholic Extract, Antibacterial Effect.

ABSTRACT

         Background and Objectives:  Many species of  Ziziphora have been used in traditional medicine in the Azarbaijan region, northwest of Iran. This study aimed to determine antibacterial activity of essential oil and methanol extract of Ziziphora tenuior on some pathogenic bacteria isolated from urogenital tract infections.

         Methods: The essential oil and methanol extract of Z. tenuior were obtained by Clevenger and maceration methods. Under sterile conditions, the required amount of urine was taken from patients referred to a number of clinics in Tabriz during 2014. After identification of the isolates using standard microbiological methods, antimicrobial effects of the essential oil and methanol extract of the plant on the isolates were evaluated by determining minimum inhibitory concentration (MIC), minimum bactericidal concentration, and antibiogram test.

          Results: The MIC for essential oil of Z. tenuior was 250µg/mL for most Gram-negative bacteria except Pseudomonas aeruginosa. Moreover, the MIC for Staphylococcus aureus was 250µg/mL and 500µg/mL for other strains of Staphylococcus.

           Conclusion: Comparison of the inhibitory and bactericidal effects of the essential oil and methanol extract of Z. tenuior showed that the essential oil is able to inhibit growth of the bacteria tested even in low concentrations. Further studies are required in this regard using animal models.

         Keywords: Antibacterial Agents, Ziziphora tenuior, Plant Extracts, Urinary Tract Infection. 

ABSTRACT
        Background and objectives: Synthesis and characterization of several metal complexes (metal ions: Co2+, Ti4+ and Ce3+) of macroacyclic Schiff base ligand have been reported. The Schiff base ligand is prepared from the condensation reaction of 1, 4-di-(4-fluoro-2-aminophenoxy) butane with salicylaldehyde in ethanol. In addition, antibacterial activity of metal ions, Schiff base ligand and their complexes have been investigated. Recent studies show that many Schiff base complexes have antibacterial activity against Gram-positive and Gram-negative bacteria. Therefore, we aimed to synthesize new Schiff base complexes and evaluate their antibacterial activity against a number of Gram-positive and Gram-negative bacteria.
         Methods: Schiff base ligand and their complexes were characterized by mass spectrometry and IR, H-NMR and C-NMR spectroscopy. The in vitro antibacterial activity of the Schiff base ligand, metal ions and their complexes were evaluated against some Gram-positive and Gram-negative bacteria by disk diffusion method and determining minimum inhibitory concentration.
          Results: In this study, the Schiff base complexes had good antibacterial activity, but the Schiff base ligand and metal ions did not show any antibacterial effect. In some cases, the antibacterial effect of the complexes was higher than that of the standard antibiotics tetracycline and gentamycin. The titanium complex showed the highest antibacterial activity in both methods. This complex created the largest growth inhibition zone (diameter: 100mm) against Staphylococcus aureus, and had the lowest minimum inhibitory concentration against Bacillus subtilis (6.75 mg/ml).
          Conclusion: The compounds synthesized in our study have strong antibacterial activity.
          Keywords: Schiff base complex, Schiff base ligand, antibacterial activity, Staphylococcus aureus, Bacillus subtilis.

ABSTRACT
       Background and Objective: Nanobacteria are nanometer-scale particles with different shapes, which have been a subject of debate in modern microbiology. They belong to a proposed class of living organisms, specifically cell-walled microorganisms with a size much smaller than the generally accepted lower limit for life. Since some microorganisms are able to continue growth at high temperatures, we aimed to isolate thermophilic bacteria from Gheinarcheh hot spring in Ardabil (Iran) and identify the characteristics of these microorganisms.
       Methods: Microbial mats were found in cultures from Gheinarcheh hot spring in North West of Iran. Synthetic media were prepared and used for isolation of protease-producing thermophilic bacteria, and identification of the features of microbial mats. Cultures were incubated at temperature range of 60-120 oC. Scanning electron microscopy, DNA extraction and polymerase chain reaction were used to further identify characteristics of the microbial biofilms.
        Results: Microbial biofilms of nanoparticles were detected in our samples. Growth of the bacteria increased at all temperatures tested. Results of scanning electron microscopy showed nano-sized particles in the scale of 60 nm. No band was visible in gel electrophoresis of polymerase chain reaction products.
Conclusion: This study is the first to report the presence of hyperthermophilic nanobacteria in Iran.
      Keywords: Nanobacteria, Hyperthermophile, Microbial Mat.