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In this study, the antimicrobial properties of bacterial cell and cell free culture supernatant of Lactobacillus helveticus was investigated both in vitro and in vivo (food). For this purpose, at first, cell free culture supernatant (CFS) was prepared from the mentioned Lactobacillus strain and then divided into three groups (control, treated by heat (100 °C for 15 min) and neutralized by NaOH). Antimicrobial activity of supernatant treated or no treated was investigated utilizing agar well diffusion and Disk diffusion method against two pathogenic bacteria including Salmonella enterica subsp. enterica and Staphylococcus aureus. Moreover, the antimicrobial activity of L. helveticus in cherry juice was evaluated during 24 h of incubation. The results showed that unheated and heated CFS were able to inhibit both pathogenic bacteria, but neutralized CFS had no antimicrobial activity. Inoculation of L. helveticus in cherry juice effectively (P <0.05) prevented the growth of Salmonella and Staphylococcus during the fermentation period. Therefore, based on the results, L. helveticus and its CFS can be used as an alternative to chemical preservative and as a natural antimicrobial source in the food industry. [ABSTRACT FROM AUTHOR]

Characterization of lactic acid bacteria (LAB) isolated from rarely studied fermentation substrates can lead to isolate unique microorganisms. In the present study, predominant LAB was isolated from fermented acorn using repeat of back-slopping process, and then the isolate was identified by PCR. Subsequently, probiotic properties of the isolate (including resistance to acid and bile, antibacterial, auto and co-aggregations, antibiotic susceptibility and blood hemolysis), as well as its antifungal effect were studied. Sequencing results of the PCR products led to the identification of Pediococcus acidilactici as predominant LAB isolate. The survival percentage of the isolate in continuous acid and bile treatment was equal to 72%. The inhibitory effect of the isolate on Bacillus cereus was also significantly (P<0.05) higher than the other foodborne indicator bacteria. Furthermore, crude cell free supernatant (CFS) obtained from LAB culture completely inhibit the growth ofB. cereus; meanwhile, its naturalized CFS had no inhibitory effect on Salmonella enterica. LAB isolate had also proper auto and co-aggregation (with E. coli) potentials and had no hemolytic activity. Antifungal activity of the isolate against Aspergillus niger was also verified. By considering the proper probiotic and antifungal potentials of the P. acidilactici isolated from fermented acorn it is possible to use the isolate as microbial starter, adjunct, probiotic and or protective culture in fermentation industries. [ABSTRACT FROM AUTHOR]

Background and Aim: Bacterial enteritis occurred in neonatal lambs, is an economically important disease that can cause high morbidity and mortality in lambs, therefore, emergency antibacterial treatment is necessary. Malva sylvestris L. plays an important role in traditional remedies for medicinal properties. The present study aimed to evaluate the antibacterial activity of M. sylvestris on bacterial pathogens isolated from the stool of diarrhetic lamb. Materials and Methods: The antibacterial activities of M. sylvestris hydroalcoholic extract (MSHE) were evaluated by agar diffusion and microbroth dilution methods against isolates of Salmonella enterica (n=10), Escherichia coli (n=10) and standard strains S. enterica PTCC 1709-CIP104115, E. coli PTCC1270. Results & Conclusion: The results of plant extract efficiency against clinically isolated reported as Minimum Inhibitory Concentration (MIC) test and Minimum Bactericidal Concentration (MIC) test toward E. coli (MIC: 11.56±0.0 mg×mL-1 and MBC: 21.25±0.0 mg×mL-1) S. enterica (MIC: 42.50±0.0 mg×mL-1 and MBC: 80.00±0.0 mg×mL-1). The conclusions of this study indicated that M. sylvestris revealed antibacterial properties and this plant could be a good candidate for the generation of new wide spectrum antibacterial agents.

Background: Marine life has long been used for their bioactive compounds. Several amazing compounds with different biological activities have so far been identified in tunicates. The aim of the current study was to evaluate the antimicrobial activity of tunichrome released from phallusia nigra marine tunicates collected from Bushehr province coasts, against four strains of Staphylococcus aureus, Bacillus cereus, Salmonella enterica, and Escherichia coli. Materials and Methods: Thirty samples of phallusia nigra marine tunicates were randomly collected from Nayband Bay in Bushehr province, and then their tunichrome was extracted and lyophilized. The antimicrobial activity (MIC and MBC) of the tunichrome extract was evaluated by agar well diffusion and broth macrodilution methods against four strains of foodborne pathogens. Chemical composition of methanol: chloroform:n-hexane extract of the tunichrome was detected by Gas Chromatography-Mass Spectrometry (GC-MS). Results: According to the results, the tunichrome extract showed significant inhibitory and lethal activities against all four studied bacterial strains. However, its antimicrobial activity was higher against Bacillus cereus and Salmonella enterica. The presence of antimicrobial compounds detected by GC-MS confirmed the results of the antibacterial activity of the tunichrome. Conclusion: According to the results, the tunichrome released from phallusia nigra marine tunicate can be an appropriate marine source of antimicrobial compounds with significant performance against foodborne pathogens. According to the literature, the secondary metabolites in the tunichrome have potential biological and neutraceutical effects which require more laboratory studies. [ABSTRACT FROM AUTHOR]

Background and Aim: At the present time one of the strategies in vaccine design is generation of fusion proteins containing (including) immunogen of infectious agents and adjuvants. In this study design and construction of E2-fliC fragment as a vaccine candid was conducted by using fliC gene from Salmonella enterica and E2 gene from hepatitis C virus. Materials and Methods: To prepare the E2-fliC construct, E2 and fliC fragments were first amplified from pBluscript-E2 and pBluscript-fliC, respectively by PCR method. To generate pcDNA-E2-fliC plasmid, E2 was subcloned into plasmid pcDNA3.1 (+) which was extracted from DH5α cells. The fliC sequence was then cloned into the pcDNA3.1-E2. To evaluate the expression of E2-fliC construct, it was inserted into the pEGFP-N3 expression vector. Then COS-7 cells were transfected with pEGFPN3- E2-fliC to evaluate the expression of the fusion protein by observation of the EGFP signal under the fluorescence microscope. Results: By development of GFP fluorescent using fluorescence microscopy the most expression of E2-fliC construct was observed at 24h after transfection. The accuracy of the recombinant plasmid pcDNA-E2-fliC was confirmed by PCR, restriction enzymes and DNA sequencing. Conclusion: Our findings suggest that E2-FliC fusion protein has expressed efficiently and most likely similar to HCV E2 protein induces immune system of mice after their immunization with pcDNA-E2-fliC.

Background and Objective: Salmonella is one of the most important zoonotic pathogens responsible for food-borne infections all over the world. Poultry products are widely acknowledged to be a significant reservoir for Salmonella. This study was done to evaluate the antibiotic resistant of Salmonella enterica producer of beta lactamase spectrum in poultry. Methods: In this descriptive – laboratort study 70 Salmonella enterica serotypes were collected from poultry. All Salmonella isolates were tested to antimicrobial susceptibility testing by the Kirby-Bauer disk diffusion according to Clinical Laboratory Standards Institute (CLSI). Twenty-nine antibiotics were used in this study. Klebsiella pneumoniae; ATCC 700603 was used as quality control strains. The isolates were determined to be ESBL-producing Salmonella by the conventional double-disk synergy and genotypic method. Results: Among 70 salmonella isolates, the most prevalent serotypes were S.typhimurium and S.enteritidis. All serotypes were susceptible to gentamicin, ciprofloxacin, oflaxacin, imipenem, enrofloxacin. The common resistance was observed to cephalexin (96%), cefazolin (96%) and cephalotin (65%). Among the 70 Salmonella isolates studied, multi-drug resistance was observed in 59 (84%) isolates. Forty-seven (67%) isolates were found to be ESBL-producing isolates. PCR assay of all isolates showed that 17 isolates (33.3%) carried bala CMY2 gene. Conclusion: This study showed that antibiotic resistance to Salmonella enterica serotypes is due to beta lactamase enzyme in this strain is considerably increased in poultry.

Chicken meat is one of the most popular and perishable foods. One of the effective ways to increase the retention time of fresh chicken meat is the use of appropriate packaging coatings containing natural antimicrobial compounds. The aim of this study was to investigate the antimicrobial effect of soy protein coating containing tarragon essential oil on chicken meat stored in a refrigerator.Tarragon essential oil was extracted by water distillation method and its antimicrobial properties were tested on Staphylococcus aureus PTCC 1113, Salmonella enterica PTCC 1709, Escherichia coli PTCC 1399, and then the effect of concentration 0, 2 and 3% (vol / vol) soluble essential oil in soybean protein coating on these bacteria were studied. Finally, the antimicrobial effect of soy protein content containing tarragon essential oil on chicken fillets kept in the refrigerator was investigated and characteristics of the changes in its chemical and organoleptic properties were evaluated.The highest inhibitory concentration of essential oil was from Staphylococcus aureus, and the lowest was E.coli and Salmonella enterica. The total microbial count for the sample treated with 3% essential oil during the 12 days storage in the refrigerator was significantly lower than the control sample (P <0.05). The greatest effect of antimicrobial films after 12 days of storage in the refrigerator was on inoculated samples of Staphylococcus aureus. Protein film of 3% essential oil prevented the increase of pH and peroxide value during the storage period in the refrigerator. According to the sensory evaluation results, the film containing 2% essential oil obtained the highest overall acceptance rating. Although this property is reduced by the mixing of essential oil with film coating. The essential oil coating also has positive effects on the chemical and organoleptic properties of chicken fillet. [ABSTRACT FROM AUTHOR]

Extracts, herbal essential oil and natural ingredients have known antibacterial properties and can be used as food preservatives. Quinoa seed is a rich source of protein with strong antioxidant and antibacterial properties than other cereals.The aim of this study was to investigate the antimicrobial activity of peptide extracted from quinoa on Staphylococcus aureus and Salmonella enterica bacteria.To determine the optimal condition of the peptide hydrolysis with the best antimicrobial property was used pepsin and alcalase enzyme at different temperatures and times.Antibacterial effects of hydrolyzed peptide from quinoa proteins on two types of gram positive and negative bacteria (Staphylococcus aureus and Samunellaantrica) were compared with the gentamicin antibiotic by Agar well diffusion method.The highest growth inhibition zone in Staphylococcus aureus and Salmonella enterica were seen at enzyme activity 60 (Anson per kg protein), Temperature of 50, 150 minutes and 800 μg / ml concentration(13.13 ± 1.00 for Staphylococcus aureus and 11.00 ± 1.1 for Salmonella enterica).According to the findings, the peptide derived from protein quinoa has a good inhibitory effect on Staphylococcus aureus and Salmonella enterica bacteria. It is recommended that further research is done on the quinoa seed and its peptides be used as a natural preservative in foods. [ABSTRACT FROM AUTHOR]

Background and Aim: At the present time one of the strategies in vaccine design is generation of fusion proteins containing (including) immunogen of infectious agents and adjuvants. In this study design and construction of E2-fliC fragment as a vaccine candid was conducted by using fliC gene from Salmonella enterica and E2 gene from hepatitis C virus. Materials and Methods: To prepare the E2-fliC construct, E2 and fliC fragments were first amplified from pBluscript-E2 and pBluscript-fliC, respectively by PCR method. To generate pcDNA-E2-fliC plasmid, E2 was subcloned into plasmid pcDNA3.1 (+) which was extracted from DH5α cells. The fliC sequence was then cloned into the pcDNA3.1-E2. To evaluate the expression of E2-fliC construct, it was inserted into the pEGFP-N3 expression vector. Then COS-7 cells were transfected with pEGFPN3- E2-fliC to evaluate the expression of the fusion protein by observation of the EGFP signal under the fluorescence microscope. Results: By development of GFP fluorescent using fluorescence microscopy the most expression of E2-fliC construct was observed at 24h after transfection. The accuracy of the recombinant plasmid pcDNA-E2-fliC was confirmed by PCR, restriction enzymes and DNA sequencing. Conclusion: Our findings suggest that E2-FliC fusion protein has expressed efficiently and most likely similar to HCV E2 protein induces immune system of mice after their immunization with pcDNA-E2-fliC. [ABSTRACT FROM AUTHOR]

Background and purpose: Intestinal bacterial infections are treated with antibiotics; but there are some reports on the effects of medicinal plants in digestive disorders. Today, medicinal herbs are more suggested due to increasing resistance of bacteria to antibiotics, people are more relying on the medicinal herbs. This study aimed to evaluate the antibacterial effect of orange peel extract. Materials and methods: After collecting orange peel samples, the methanol extract was provided using maceration method and the effect of this extract against the standard strains of bacteria (Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enterica) was assessed using microdilution (well plates) in brain-heart infusion medium. Results: In this study, all the standard strains of bacteria in wells were sensitive to the extract. Meanwhile, different minimum inhibitory concentrations (MIC) were observed in various genera. The first group (Bacillus cereus) was the most sensitive due to receiving MIC=3.12 μl/ml of the extract. In the second group, Staphylococcus and Salmonella were expressed as they were administered administered MIC 6.25 μl/ml of the extract. The third group (Klebsiella and Pseudomonas) was listed as the most resistant group, which received MIC=12.5 μl/ml of the extract. Conclusion: Research on the use of natural products, which are used in traditional medicine for gastrointestinal disorders, can be valuable in terms of antibacterial activity and adjustment of microbial flora. In this study, it was demonstrated that orange peel can inhibit the growth of many bacteria in-vitro. [ABSTRACT FROM AUTHOR]

Background: The infections caused by Salmonella enterica serovar enteritidis (Salmonella enteritidis) have been increasing in developed and developing countries. The aim of this study was to investigate the genetic relationship between the strains of Salmonella enteritidis. Methods: In a descriptive study from 2008 to 2010, clinical Salmonella enteritidis strains were collected from the patients referred to different hospitals in Tehran. The strains identified by biochemical and serological methods. Genetic relationships between the isolates were investigated using pulsed field gel electrophoresis (PFGE) method. Findings: Of 40 Salmonella enteritidis isolated strains, two PFGE profiles were obtained which among them, 32 (80%) and 8 (20%) of isolates belonged to cluster A and cluster B, respectively. Based on PFGE patterns, 28 (70%) strains exhibited nine bands and were belonged to cluster A. Conclusion: The result of this study indicated that isolated Salmonella enteritidis strains belonged to the closed clones. [ABSTRACT FROM AUTHOR]

Background: Ribosomal DNA (rDNA) genes contain signature structures which are unique for groups of organisms. Considering their great number in cells and their protected areas, they render ideal targets for specific nucleic acid probes. The present study aimed to investigate the capability of some specific regions of 23S rDNA gene as a DNA target for differentiation and screening of Escherichia coli, Salmonella enterica, and Shigella dysenteriae. Methods: Bacterial reference strains used in this study were E. coli, S. enterica and Sh. dysenteriae that were provided by the centers for microbial culture collection (CMCC) at Pasture Institute of Iran. DNA extraction was performed by boiling method. Alignment of the 23S rDNA sequences of bacterial species was performed by using AlignX (a component of Vector NTI Advance 11.0) and areas displaying sequence divergence among species were used for designing universal primers and individual bacteria specific probe. Findings: The universal polymerase chain reaction (PCR) products of each bacterial species showed bands of approximately 880 bp to be being equivalent to the fragment size of 23S rDNA gene. Different size bands of 23S rDNA probes were produced and included 228 bp for E. coli, 444 bp for S. enterica, and 776 bp for Sh. dysenteriae. Conclusion: Comparative sequence analysis of variable and specific regions of 23S rDNA genes among the studied bacterial species showed that we were able to amplify specific target among universal region for the detection of many enteric pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Background: Salmonellosis is one of the most important prevalent bacterial infections, after a decade of its recognition. Antibiotic therapy in salmonellosis is restricted to typhoid fever and acute infections. After the first reporting of resistance in S. Typhimurium DT 104, nowadays, developing resistance in Salmonella, specially, ESBL (such as CTX-M) species is an important issue in salmonellosis. In this study, we evaluated bla-ctx-m-type gene in clinical isolates of Salmonella enterica. Methods: In this cross-sectional study, we collected clinical isolates of patients in 18 months. Initially, we surveyed drug sensitivity with disk diffusion method, and then determined MIC of resistant isolates with E-test stripes. The existence of ESBL (extended spectrum beta-lactamase) enzymes was examined by ESBL disks in Double Disk method, and these resistances was evaluated with PCR by using a pair of universal primers. Finding: 36 isolates were sensitive to all of antibiotics, but, in 60 isolates there was at least one resistance. In 45 isolates, there were multi drug resistance (MDR) phenotypes. Resistance to ampicilin was the highest percent, whereas, there was not any resistance to imipenem and ciprofloxacin, which were improved with E-test strips. ESBL evaluation, showed producing cefotaxime ESBL in 5 isolates and ceftazidim ESBL in 4 isolates; 2 isolates of these had bla-ctx-m-type gene in plasmid. Conclusion: Detection of MDR trait, especially extended spectrum beta-lactamases in resistant clinical Salmonella isolates, point to the attention in usage of extended spectrum cephalosporins and detection of resistance rate in a nation level. [ABSTRACT FROM AUTHOR]