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Background and Aim: EHEC has been known as one of the most dangerous pathogenic agents, with a high rate of mortality and morbidity at the time of epidemic food poisoning. It produces cytotoxins named shiga toxins which cause human and animal diseases. Determination of the genetic origin of shiga toxin is important for controlling its dissemination among different species of E.coli. To produce large amounts of this toxin for medical purposes, it is important to determine its genetic origin to evaluate its expression level.

Materials and Methods: 400 samples of fecal material of cows and calves from three farms in Tehran were collected in sterile tubes. Total DNA extracted from each isolate was prepared for PCR. Phage induction method using ciprofloxacin was done to extract lysogenic phages from isolates. Then the phages were purified through enzymatic hydrolysis and filtration. PCR was done again to demonstrate the existence of shiga toxin gene on the phage genome.

Results: From 34 shiga toxin producing isolates, 24 isolates (70.5%) produced shiga toxin 1, 8 isolates (23.5%) produced shiga toxin 2 and 2 isolates (6%) produced both toxins. Also the frequency of shiga toxin encoding gene on phage genum was determined. 26 isolates (76.5%) out of 34 shiga toxin producing isolates had lysogenic phages.

Conclusion: It is demonstrated that shiga toxin can be encoded through chromosome, plasmid or phage. If there is a receptor for the phage on the bacterial surface, it can enter into the bacteria. Shiga toxin encoding gene can spread among different strains of a bacterium or different bacteria if it is carried on phage genome. In order to control toxin production among different species of E.coli, determination of shiga toxin gene origin is necessary. On the other hand, shiga toxin has anti cancer effects and if shiga toxin is to be used as an anti cancer drug, it is desirable to produce large amounts of this toxin. Therefore its genetic origin should be determined.

 

Conflict of Interest: Nill

Received: July 2, 2008      Accepted: August 4, 2008

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Background and aim: Due to some drawbacks associated with gene delivery vehicles including viral and non-viral vectors, scientists have continued their efforts to find an ideal gene delivery vehicle. Bacteriophages have been proposed as an attractive alternative gene delivery vehicle in view of their advantages such as protection of transgene, lack of immunogenicity and stability in different conditions. This study has been conducted with the aim of obtaining a construct based on M13 phage and evaluating its capability for delivering transgene to eukaryotic cells. Material and Method: pCMV-Script EX phagemid was constructed by intracellular excision of Lambda Zap CMV XR vector bearing GFP gene. Packaging of the construct using helper phage resulted in M13-GFP phage particles which used for transfection of human AGS cell line. Finally internalization of the phage particles into the AGS cell line was evaluated by PCR and florescence microscopy. Results: Examination of the treated cells with florescence microscopy indicated that M13-GFP phage particles were able to internalize and express the transgene in eukaryotic cells, but the efficiency of this trasfer was very low. PCR analysis showed that internalization of the M13 GFP gene vehicle to eukaryotic cells was dose dependent. Conclusion: The results indicated that M13 phage could be an appropriate gene delivery vehicle, because it had trivial tropism for eukaryotic cells. This means that after displaying or coupling of appropriate targeting molecules on the surface of phage particles, transgene can effectively be delivered to the target cells. Key words: Gene therapy, Gene delivery, M13 phage. Received: Sep 29, 2013 Accepted: Jan 20, 2014

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Background and Aim: Gastroesophageal Reflux (GER) is defined as the return of gastric contents into the esophagus or oropharynx without effort which is a common problem in the children. Ultrasound is a sensitive and accurate method for evaluation of reflux. The aim of this study was to compare the abdominal esophagus length between the children below 2 years of age with gastroesophageal reflux and children of the same age without gastroesophageal reflux. Material and Method: This was a case-control study and included 100 children less than 2 years of age. The children were allocated to two groups, 50 children without GER and sonographic evidence as control group and 50 with GER confirmed by sonographic or barium swallow under fluoroscopy as our case group. The length of the abdominal esophagus was measured according to the protocol. Using SPSS 21 software, data were analyzed by statistical tests. Result: The average length of the abdominal esophagus in the patients with GER and those without GER were 19.46±4.54 and 26.23±5.01 respectively. There was a significant difference between the two groups in regard to the length of abdominal esophagus. Conclusion: According to the results of this study, it seems that the length of the abdominal esophagus is shorter in the children under 2 years of age with gastroesophageal reflux compared to those without gastroesophageal reflux. Therefore, measurement of abdominal esophagus length by ultrasound can be a useful parameter in children with gastroesophageal reflux. Keywords: Gastroesophageal reflux, Abdominal esophagus length, Children below 2 years old, Ultrasound. Received: Jan 7, 2014 Accepted: Jun 10, 2014

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Background and Aim: Salmonella spp. is important in medicine. Most related infections are self-limited. Antibiotics are used for high risk patients such as children, old individuals and immune-compromised patients. Overuse of antibiotics has led to increased emergence of multi-drug resistant bacteria which are life-threatening. Phage therapy is an alternative method to reduce antibiotic use.

Materials and Methods: Waste water samples were collected from sewage system of Rasht City twice a month. Prepared suspensions of Salmonella reference collection A (SARA) number 1, 6 (S. typhimurium) and 46, 48, 51 (S. paratyphi B) and double LB broth were mixed with filtrated waste water. After centrifugation and filtration, serial dilutions were prepared and phages were isolated. Morphologic characteristics were determined using TEM (Transmission electron microscopy). Finally, to assess the spectrum effect of the bacteriophages, we determined host range against 19 SARA strains.

Results: Clear plaque formation on double layer LB agar indicated lysis of the test strains by isolated phages.  The results of host range showed that some of the phages were able to lyse a number of other bacteria of SARA collection. Imaging with TEM indicated that the isolated phages against SARA collection belonged to Siphoviridae and Podoviridae families.

Conclusion: This is the first report of phage isolation against Salmonella reference collection in Iran. SARA no. 51 (S. paratyphi B) was lysed by S. typhimurium phage. It means that the isolated phage may lyse S. typhi, which is an important human pathogen.

Keywords: Salmonella reference collection, Bacteriophage, TEM, Morphology.

Received: Oct 31, 2016      Accepted: Jan 10, 2017

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Background and Aim: Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal diseases and its prevalence rate in various countries, including Iran has been on the rise. The aim of this study was to investigate the risk factors and prevalence rate of this disease in Sanandaj.
Materials and Methods: In this descriptive, analytical study, 430 people were selected via random cluster sampling. Data were collected by carrying out interviews with the participants from May 2014 to June 2015. Using a questionnaire, we recorded data  about the demographic characteristics, symptoms of gastroesophageal reflux disease and risk factors for the disease. Then, we measured and recorded the participants’ blood pressure, height, weight, and BMI. People who had experienced episodes of mild symptoms of heartburn for two days or more in a week or experienced moderate to severe symptoms for more than once in a week were regarded as cases of reflux. Data analysis was performed by using STATA-11 software.
Results: From 410 patients, 41% were male and 59% (241 persons) were female with the mean age of 37.75 years. The prevalence rate of gastroesophageal reflux in the study population was 30%. We found no statistically significant difference between the patients and healthy individuals in relation to the risk factors for gastroesophageal reflux.
Conclusion: Considering the high prevalence of GERD in Sanandaj, it is of great importance to provide necessary training about the risk factors, prevention, and appropriate treatment of the disease for the public.
Keywords: Gastroesophageal reflux, Prevalence, Sanandaj
Received: Feb 22, 2017       Accepted: Jun 17, 2017

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Background and Aim: Atherosclerosis is known as a multifactorial inflammatory disease. Trimethylamine N-oxide (TMAO) as a risk factor, has a potential to trigger or enhance the immune inflammatory reactions in atherosclerosis. Yet, The exact mechanism by which TMAO induces inflammation during atherosclerosis is not well understood. The present study was designed to evaluate the expression of IL-1β, IL-6, and TNF-α mRNA in response to treatment of macrophages with different concentrations of TMAO.

Material and Methods: In this experimental in-vitro study, U937-derived macrophages were treated with different concentrations of TMAO (37.5, 75,150 and 300 µM) for 24 h. A group of cells were also treated with tunicamycin as positive control for stress. RT-qPCR was used to evaluate the expression of IL-1β, IL-6, and TNF-α mRNA levels. One-Way ANOVA and Post-hoc Dunnett test were used to compare the mean value of every group with that of control group.

Results: Although TMAO increased expression of IL-1β, IL-6, and TNF-α mRNA, only 300 µM of TMAO significantly increased expression of IL-1β mRNA compared to the control cells (P<0.001). Tunicamycin increased expression of IL-6 significantly.

Conclusion: The results of this study showed that among the above mentioned cytokines, IL-1β as a proinflammatory cytokine had a greater role in inflammatory reactions, induced by TMAO as a risk factor for atherosclerosis.

Keywords: Cytokine, Atherosclerosis, Trimethylamine-N-Oxide, Tunicamycin, Macrophage.

 

Received: Nov 21, 2017     Accepted: May 15, 2018

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Background and Aim: Infections of antibiotic-resistant bacteria make their treatment difficult and sometimes impossible. So, scientists are looking for new solutions to fight these bacteria. Phage therapy can replace antibiotic therapy, especially in multidrug-resistant bacteria. Therefore, we aimed to isolate bacteriophage that is effective against common gram-negative bacteria.
Materials and Methods: In this experimental study, 250 ml of hospital and municipal wastewater samples were gathered. The samples were centrifuged at 4000 rpm for 10 minutes, the supernatants were filtered through a 0.22 μm filter. To phage enrichment, 50 ml of filtered water twice the volume of nutrient broth and host bacteria were incubated at 37 C for 24 hours in a shaker incubator. The double-layer agar method was used to see bacteriophage plaque. Transmission electron microscopy was used to investigate the characteristics of the isolated bacteriophage.
Results: Lytic bacteriophage effective to Shigella sonei was found by testing on municipal wastewater. Electron microscopy showed that the bacteriophage belonged to the family Microviridae. However, bacteriophage against other Gram-negative bacteria was not found in the test on hospital wastewater samples.
Conclusion: The found bacteriophage had a specific lytic effect against Shigella sonei, this bacteriophage could be used for the study of phage therapy for Shigella infection with antibiotic resistance.