Seyedehmahsa Mirmostafa, Azam Haddadi, Noor Amir Mozaffari Sabet3,
Volume 3, Issue 12 (1-2014)
Abstract
Aim and back ground: In recent years the threat of acquisition of antibiotics resistance caused by over use of antibiotics is growing. The purpose of this study was to survey the pattern of antibiotic resistance and evaluate of Multi-drug resistance Escherichia coli and analyze the plasmid profile of these clinical strains.
Materials and Methods: This study was performed on 83 clinical Escherichia coli, obtained from four hospital (imam Khomeini, Alborz, Kasra, qaem) and two private laboratories (Razi and Kavosh), of Karaj city. Isolates were identified as Escherichia coli based on standard biochemical tests. The isolates were screened for Antimicrobial susceptibility test by 20 antibiotics using Kirby-Bauer disk diffusion method. Plasmid profiles of these isolates have been analyzed by alkaline lysis method.
Result: Antibiotic resistance pattern were observed as follows: Nitrofurantoin 8.4%, Tetracycline 63.8%, Amoxicillin 83%, Ofloxacin 30%, Levofloxacin 30%, Co-trimoxazole 59%, Amikacin 18%, Imipenem 25.3%, Choloramphenicol 16.9%, Cephalexin 61.4%, Gentamycin 28.2%, Norfloxacin 33.7%, Nalidixic acid 56.6%, Cephalothin 48.2%, Ciprofloxacin 32.5%, Ceftazidime 27.7%, Ceftriaxone 37.3%, Ceftizoxime 16.9%, Cefotaxime 38.5%, Amoxycillin/Clavulanic acid 68.7%. Of 83 isolates 92.77% (77) isolates were resistance to more than two unrelated drugs. Of 83 isolates, 65 isolates, (78.3%) showed the presence of plasmid.
Conclusion: The results of this study indicate a growing resistance pattern to the first line antibiotics, prescribed for urinary tract infection. High presence of plasmids in these strains, play an important role in multidrug resistance in these bacteria.
M.j. Mostafapour, Salman Ahmady- Abchin, Moein Saffari,
Volume 4, Issue 14 (4-2014)
Abstract
Background and purpose: Biosurfactants are amphiphilic biological compounds produced extracellularly or as part of the cell membranes by a variety of microorganisms. The aim of this study was to identify a strain of bacteria of the genus Acinetobacter.spp biosurfactant producers.
Materials and Methods: In this study, different samples of oil, water and soil contaminated with oil were prepared. Hemolytic activity, emulsification activity and measurement of surface tension were used and selected strains were identified by biochemical tests. The nature and effect of bacterial biosurfactant was evaluated for strain selection.
Results: In this study, eighty eight bacterial strains were isolated. Twenty four strains have been isolated from the isolated strains with hemolytic activity, among which 12 strains with high emulsification activity of 70% were separated. Finally, 4 strains were able to reach the surface tension to less than 40mN/m. On the basis of biochemical tests, a strain selected for this study were identified as Acinetobacter ssp The nature of the biosurfactants were determined by TLC, kind of the glycolipid. Furthermore, the produced biosurfactant of the selected strain had antibacterial activity against six infectious bacteria. The most sensitive ones to the effects of bacterial biosurfactant extract of Acinetobacter ssp, were Staphylococcus aureus and the most resistant bacteria to extract were Proteus mirabilis, the results of MIC, MBC showed that Extract dilution MIC at 63 and MBC Extract in concentration of 125 mg/ ml on Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa were the most effective. The findings indicated that the bacterial strains with over 70% of emulsification and the surface tension below 40 mN/m, are able to produce biosurfactant and oil degradation having stronger antibacterial effects.
Conclusions: According to these results it can be said that this bacterium has a great potential for applications in biotechnology and environmental requirements.
Samaneh Golayj, Ali Nazemi, Mostafa Jafarpour,
Volume 4, Issue 15 (9-2014)
Abstract
Aim and Background: Thermostable DNA polymerase enzyme has been taken much into consideration due to its application in PCR and molecular biology researches and it has doubled the importance of the study on the various thermostable DNA polymerase. The purpose of this study was to assay the function and efficient production of the cold sensitive thermostable DNA polymerase and its quick and cheap purification.
Material and Methods: After synthesis of the designed gene artificially, it was cloned into the pET28 vector and then was transferred into E.coli. IPTG was used as an inducer in the study of gene expression. Initial purification of the enzyme was performed by heat treatment at 72 °C and precipitation of other insoluble proteins by centrifuge. The DNA synthesis activity of crude extract was compared with commercial enzyme.
Result: Recombinant cold sensitive and thermostable Taq DNA polymerase expressed in E.coli showed a significant advantage and more desirable functionality such as activity and thermostable compared to commercial enzyme.
Conclusion: With regard to importance and application level of thermostable DNA polymerase in molecular biology, the production method used in this study is practical and cost effective. Additionally, the simplicity of producing method of this enzyme and its accuracy is a good reason for artificial and local production of highly pure cold sensitive Taq DNA polymerase.
Hamid Hoseinian, Behnaz Barzaminy,
Volume 4, Issue 16 (12-2014)
Abstract
Aim and Background: L-asparaginaseΙΙ (E.C. 3.5.1.1) has effective usage for treatment of acute lymphoblastic leukemia. This enzyme is isolated from bacterial sources and it is commercially available as an anti-cancer drug. This enzyme catalyzes the hydrolysis of L-asparagine to ammonium and aspartate. Unlike Normal cells, the cancer cells strongly require L-Asparagine leading to destruction of these cells. The propose of this project is cloning of L-asparaginaseΙΙ gene from E. coli in B. subtilis to produce the mass of this enzyme.
Materials and methods: L-asparaginaseΙΙ gene is isolated from E. coli by PCR approach. The amplified fragment and expression shuttle vector pMR12 are digested by HindΙΙΙ and BamHΙ enzymes. The ligation between DNA fragment and the cloning shuttle vector is done by standard method. In the next step recombinant vector is transferred to E. coli JM101 by cold calcium chloride treatment and finally introduced into B. subtilis by a chemical method.
Results: in this experiment, ansB gene is isolated from E. coli by PCR and cloned into the expression shuttle vector pMR12. Existence of gene with 1047 bp lenght is confirmed by enzymatic analysis and PCR reaction. Then recombinant vector cloned in E. coli at first and then in B. subtilis. Finally the plasmid extracted and compared with the band of expersion shuttle vector containing ansB gene to confirm.
Conclusions: In this study, we tried to clone the ansB gene in B. subtilis using expression shuttle vector pMR12. This is the first report of ansB gene cloning in B. subtilis.
Hamid Tebyanian, Behjat Yousefi Sabete Mozhdeheh,
Volume 5, Issue 18 (4-2015)
Abstract
Aims and Background: E.coli O157:H7 is a bacterium from the family Enterobacteriaceae which are Gram negative cocobacilli, causing gastrointestinal diseases such as Diarrhea, Hemorrhagic colitis and hemolytic uremia. The aim of this study was to examine E.coli O157:H7 in plankton and biofilm status under stressed conditions of pH and ORS powder at 37 0C and then comparing their shape both in microscopic (bacterial shape) and macroscopic levels (bacterial colonies).
Materials and Methods: Bacterial strains of E.coli O157:H7 were purchased from Razi Vaccine and Serum Manufacturing Co. with No. (RITCC) 2323. The bacteria were placed in liquid Nutrient Broth culture media and then transferred to Nutrient Agar culture media into plates to examine colonial shape. Next, colonial and bacterial shapes were examined by gram dying. Counting the number of live bacteria under stressed conditions was done by poor plate method and diluting preparation. In order to determine the power of biofilm formation under stressed, microtitration plate was used and read by Elisa Reader.
Results: Bacterial shape is affected by stressed conditions. Under stressed conditions, colonial morphology and bacterial shape significantly change and the shape tends to transform to Cocci and bacilli in order to survive longer. Survival of bacteria under stressed conditions is more in biofilm state than Plankton.
Conclusion: these changes have a direct relationship with the survival of most bacteria in the digestive tract preventing the natural effect of gut antibacterial compounds on bacteria and the resistance of bacteria in biofilm is more than plankton.
Hamid Reza Khatami, Ramin Fallah Zadeh, Jalil Fallah Mehrabadi, Mohammad D Ghafari,
Volume 5, Issue 19 (7-2015)
Abstract
Aims and Background: Human granulocyte colony stimulating factor (hG-CSF) is a hematopoietic cytokine that stimulates activation of mature blood cells. Nowadays, recombinant hG-CSF is successfully used for the treatment of neutropenia in patients suffering from cancer of myeloid suppressor, bone marrow transplant, acute myeloid leukemia and acute/severe neutropenia. The aim of this study was the increased expression of hG-CSF and production of the soluble protein with disulfide bonds by E.coli strains (Origami and BL21).
Materials and Methods: The synthesized hG-CSF gene (in pGEM vector) was subcloned into pET23a expression vector and then the recombinant plasmid was transformed into Origami and BL21 hosts. Afterwards, expression levels were compared in two hosts.
Results: Enzymatic digestion results showed the accuracy of the cloning procedures in vector pET23a. Also under the same conditions and after induction of different hosts with IPTG, best hG-CSF protein expression was observed in strain Origami E.coli.
Conclusion: The results showed that E.coli (Origami) is appropriate strain for the expression of human G-CSF and this strain can be used as suitable host for the expression of this protein in higher scale.
Sara Bagheri, Pooneh Rahimi, Rouhallah Vahabpour, Seyed Mehdi Sadat, Mohammad Reza Aghasadeghi, Fatemeh Motevalli,
Volume 6, Issue 22 (4-2016)
Abstract
Aim and Background: The envelope glycoprotein E2 in Hepatitis C virus is required for host-cell entry. The nucleotide sequence diversity in carboxyl-terminus (C-terminal) of this gene results in induction of neutralizing antibody that makes this gene an important target for vaccine development studies. In this study we tried to make a recombinant pET28a (+) containing full length of the E2 gene from genotype 2a (JFH1) followed by being transformed into the E-coli (DH5a).
Material and Methods: Full-length of HCV E2 region from genotype 2a (JFH1) was amplified by PCR reaction using the specific primers including the restriction sites for EcoR1 and Nde1. The confirmed PCR product was cloned into the pET28a (+) vector and transformed into the E-coli (DH5a) using the heat shock method.
Results: The HCV E2 gene was successfully cloned into the pET28a (+) vector in full length size. Transformation of the E-coli strain DH5a by this recombinant vector was confirmed.
Conclusion: Transformation of the E-coli (DH5a) using the recombinant vector pET28a- HCV 2a (JFH1) E2 gene provides useful tools for further expression of this gene in full length size in different expression system.
Reza Yari, Afshin Choobrizian, Kyumars Safinejad,
Volume 6, Issue 24 (10-2016)
Abstract
Aim and Background: One of the most genes in exacerbation UTI is iroN gene. The purpose was determination of iroN gene prevalence in E. coli strains. To accomplish this goal can a reasonable mechanism to manage the inhibition of bacteria carrying the gene and preparation of vaccine offered.
Materials & Methods: A total of 80 samples from patients with UTI symptoms collected and Fifty E. coli isolates, identified. E. coli presence has been confirmed by biochemical and microbial tests. PCR was done by specific primers. The apmplicon size was 668 bp.
Results: Among the 50 isolated bacteria from UTIs, 9 isolates carried out iroN gene. This was equivalent 18% of total isolates. Gene prevalence in women was twice the prevalence in men. One and two urban areas had the highest prevalence of the gene.
Conclusions: The prevalence of iroN gene was relatively high. There are numerous reports of the presence of antibodies aginst iroN protein in patient's serum which is emphasis on the presence of antigenic determinant. It can be used in the preparation of a vaccine against UTI bacterial infections Produced by E. coli. Our results can also be used by epidemiologists and health care providers.
Atieh Salighe, Mohsen Zargar, Shahla Mohammad Ganji,
Volume 6, Issue 24 (10-2016)
Abstract
Aim and Background: Colorectal cancer is the third most common cancer after lung cancer, stomach and liver cancer in the world. Studies have shown that patients with inflammatory disease of the large intestine are at high risk of developing colorectal cancer are located. Several factors make inflammatory bowel disease and colorectal cancer is one of the factors involved, bacteria and toxins derived from them. Research shows that some strains of E. coli can be induced to increase the mutation rate that was established in 2010 by Cuvas-Romas and colleagues. fimC and vat1 Virulence genes in these organisms play an important role in bacteria pathogenicity. This study is to compare the virulence genes in E .coli strains isolated from samples biopsy patients' inflammatory bowel disease and colorectal cancer, intestinal tissue was performed.
Materials and Methods: 38 biopsies were obtained from intestinal tissue and E.coli bacteria in microbial and biochemical method was identified and isolated. After DNA extraction, strains for virulence genes vat1, fimC using polymerase chain reaction (PCR), were evaluated.
Results: Molecular analysis showed a significant difference between the groups studied the gene vat1 (p = 0.0245) and 42.8% of positive samples were for this gene in normal groups, 87.5% with inflammatory bowel disease87.5 % of patients with colorectal cancer were reported. But there is no significant difference between the groups in terms of fimC gene (P = 0.201). And 71.4% of positive samples for this gene in normal groups' and 93.7% in patients with inflammatory bowel disease73.3 % of patients with colorectal cancer were reported.
Conclusion: The results, to confirm the good relationship between virulence genes studied induced inflammation and proliferation by inducing mutation rate.
Noushin Kamrani Hemat, Mohsen Mirzaee, Shahin Najar-Peerayeh,
Volume 7, Issue 25 (1-2017)
Abstract
Aim and Background:Urinary tract infection is one of the most prevalent diseases in human. Unfortunately, the indiscriminate use of antibiotics leads to resistance in bacteria gradually. The aims of this study were to determine the prevalence and distribution of antibiotic resistance to tetracycline resistance genes in uropathogenic Escherichia coli isolated.
Material and Methods: In this study, 210 urine samples were collected during four months. Antibiotic susceptibility testing was performed as recommended by the Clinical Laboratory Standards Institute (CLSI) using disk diffusion method. All isolates were then examined for presence of the tetA and tetB genes.
Results: Of the 210 urine samples with UTI collected from hospitals, the 150 isolates of E. coli were isolated. Most of antibiotic resistance was related to tetracycline (68%) and least of antibiotic resistance was related to chloramphenicol (8.66%). Among isolates (86.27%), were tetA gene and in 83 isolates (81.37%) tetB gene was detected. 74 (72.45%) isolates were positive for both genes, and 5 (4.90%) isolates were negative for them.
Conclusion: Resistance to tetracycline and other antibiotics, and the presence of tetA and tetB genes in UPEC strains are alarming signs in our area. The current study strongly recommends restricted the consumption of antibiotics including tetracycline. Further studies should be conducted in order to find out the extent of the problem in other areas.
Marzie Dokht Shams Talab, Mohamad Reza Mehrabi, Mohsen Mirzaee,
Volume 7, Issue 25 (1-2017)
Abstract
Aims and Background: AmpC β-lactamases hydrolyze penicillins, cephalosporins and cephamycins and resist inhibition by clavulanate, sulbactam and tazobactam. In this study, has been paid to prevalence of AmpC beta-lactamase enzymes produced by Escherichia coli isolates from various hospitals of Kermanshah city.
Material and Methods: A total of 100 clinical isolates of Escherichia coli were collected from the city of Kermanshah and after identification screened by Disk diffusion agar method and combined disk for production AmpC beta-lactamase. The isolates that were phenotypic have features these enzymes tested by Multiplex PCR. Also resistance of ESBLs producing isolates to ciprofloxacin, amikacin, meropenem and azteronam was measured by Microdilution broth for determination MIC (Minimal inhibitor concentration).
Results: In this study, 43% of clinical isolates were Ampc beta-lactamase producers, based on phenotypic. After most review by Multiplex PCR showed 44.1% of them has Ampc beta-lactamase gene.
Conclusion: Prevalence of AmpC beta-lactamase due to ineffective prescription of the third of generation cephalosporins has become a major challenge for the treatment of disease. Phenotypic tests and Molecular methods such as PCR the detection of beta-lactamases enzymes can be very useful. Although this study has shown a high prevalence of AmpC beta-lactamase the city of Kermanshah, which is major cause of the self use of antibiotics or lack of antibiogram before beginning treatment. Lack of knowledge about phenotypic and molecular methods can provoke the development of resistance of AmpC beta-lactamase.
Elham Siasi , Farzaneh Hossieni , Pooyeh Rahiminia,
Volume 7, Issue 25 (1-2017)
Abstract
Aim and Background : Uncomplicated urinary tract infections (UTIs) are among the most common infectious diseases in human. Escherichia coli is the causal pathogen in UTIs. For treatment of UTIs, fluoroquinolones are used. fluoroqinolones-resistant E. coli was showed by alterations in the genes that encode for the quinolone target subunits.
Materials and Methods: one hundred isolates of the urinary samples were collected. E. coli isolates were identified by biochemical tests. The minimal inhibitory concentration (MIC) of fluoroquinolones were determined for isolates. DNA was extracted and PCR amplification was carried out for the specific regions of gyrA and parC genes. Then amplified regions were sequenced.
Results:rom 100 samples, 70 samples were E. coli, 30 samples were Kellebsiella. Evaluating MICs for 70 E. coli isolates to fluoroquinolones, it was found that 45 (64.28%) were resistant to quinolones. Sequencing of gyrA and parC specific subunits has revealed five single mutations in the gyrA gene and two single mutations in parC gene.
Cunclusion: Fluroquinolones are potent antibacterial agents for treatment of UTIs. Mutations of DNA gyrase and topoisomerase IV associate with the fluoroquinolones resistance in E. coli. Results have indicated a relationship between MICs of the quinolones for E. coli isolates with mutations in gyrA and parC genes. This study also signifies an association between mutations in gyrA and parC genes in E. coli isolates with fluoroquinolone resistance.
Abolfazl Jafari Sales, Haedeh Mobaiyen,
Volume 7, Issue 26 (4-2017)
Abstract
Aim and Background: The production of Extended Spectrum Beta Lactamases (ESBLs) by Escherichia coli is the main cause of resistance to Cephalosporins , Worldwide has tremendously increased. The aim of this study was to determine the prevalence of ESBL-producing E. coli and antibiotic resistance patterns of those.
Materials and Methods: In this study, 196 cases of E. coli within 6 months from patients referring to the public and private treatment centers Marand city were collected and identified by biochemical tests. ESBL screening and confirmation along with antimicrobial susceptibility test was done according to the Clinical Laboratory Standards Institute (CLSI) guidelines.
Results: Of 196 isolates, 100 isolates (51.02%) were produced ESBL. 82% of the isolates were resistant to Ampicillin and 76% of the isolates were Sensitive to Imipenem.
Conclusions: Organisms expressing ESBLs in this study were widely distributed, often possessing the multidrug resistance phenotype. Limiting the use of broad-spectrum Cephalosporins is recommended to control this high rate of ESBL expression.
Mitra Salehi , Mahsa Akhtari , Abbas Akhavan Sepahi ,
Volume 7, Issue 27 (9-2017)
Abstract
Aim and Background: Heavy metals are such as pollutant nature, under functions such as mining and industrial waste to entering the environment. Heavy metals including mercury, cadmium, nickel, arsenic, copper, lead, cobalt, silver and chrome. Some heavy metals are needed for cell growth in small amounts and it is toxic in high concentrations. High concentrations of heavy metals are created serious problems for the life of plants, animals, fishes and finally to humans who are the main consumers of these food sources. Identifying bacteria resistant to heavy metals plays an important role in relation to environmental pollution and eventually its cleanup. Therefore, in this study, the molecular heavy metal resistance in Escherichia coli strains isolated from surface water has been studied.
Materials and Methods: In this study, 120 samples of surface water in Tehran in the spring and summer of streams, rivers and sewage were collected and using capped sterile Falcon transported to the laboratory immediately. The first samples were enriched in the BHI broth culture. Then to see colonies of microorganisms, were cultured on BHI agar linear and were incubated at 37 ° C for 24 hours. To isolate strains from other bacteria grown in culture medium, used Eosin methylene blue (EMB) specific medium. Using the disk plate and serial dilution in the tube method, the resistance of bacteria to different concentrations of salt heavy metals zinc and cadmium sulfate was studied.
Results: Only 40 (33/33%) E. coli strains was isolated.The minimum inhibitory concentration (MIC) was reported for zinc sulfate salt was 12/5 mM and for cadmium sulfate salt was 10 mM.
Conclusion: By comparing heavy metal zinc and cadmium resistant in E. coli strains was found that the amount of zinc in surface water study is more than cadmium. So the zinc resistant in Escherichia coli strains is more. Generally increase in heavy metals in surface water results in increased resistance of Escherichia coli strains to heavy metals.
Cobra Moradian , Mohammad Reza Fazeli, Dariush Abedi ,
Volume 7, Issue 27 (9-2017)
Abstract
Aim and Background: Lac promoter, a regulatory gene in Escherichia coli, is a prokaryotic expression system for recombinant Interferon production. This promoter is induced by lactose or IPTG, its chemical analog. In this study, the effect of lactose and IPTG on the expression of gene was compared.
Materials and Methods: Escherichia coli BL21 (DE3) harboring Interferon β-1b gene were cultured and induced by the addition of IPTG and / or lactose. The yield of produced Interferon protein was measured.
Results: The yield of Interferon β-1b protein increased by using 0.2% lactose and 0.5 mM IPTG simultaneously as inducers in comparison with each inducer alone and it was equal to 34% of the total cell proteins.
Conclusion: In this research, with simultaneous presence of Lactose and IPTG, in comparison with each one of this inducers alon, a higher yield of the interferon beta 1b protein at a lower cost was produced.
Somayyeh Shabanpishe, Abasali Rezaeian,
Volume 8, Issue 30 (4-2018)
Abstract
Aim and Background:Today, the presence of broad-spectrum beta-lactamases in bacteria isolated from patients who express multiple drug resistance is a major health problem in most countries.
Materials and Methods:A total of 346 samples of different clinical strains of enterobacteriaceae were isolated from Kahooresten. To determine the resistance of the samples, an antibiotic test was performed. Finally, ESBL isolates were tested by PCR for TEM, CTX-M, and SHV genes.
Results:Of the 346 isolates studied, 162 isolates of Klebsiella and 132 isolates of Escherichia coli were resistant to ceftazidime antibotic or cefotaxime, or both. Also, 82 (42.26%) were isolates producing ESBL.
Conclusions:Due to the high percentage of resistance to third-generation cephalosporins, accurate antibiotic testing before antibiotics is required in infections caused by ESBL-producing organisms.
Parvin Mousavi, Saeed Zaker Bostan Abad, Reza Mirnejad,
Volume 8, Issue 30 (4-2018)
Abstract
Aim and Background: Urinary tract infections is one of the most common infectious diseases whichmany factors are involved, but bacteria such as E.coli is the most important agent of urinary tract infections. Antibiotic resistance as a major problem in the treatment and control of these infections is considered. The aim of this study was to determine the genes that cause resistance to betalactam family of antibiotics on E.coli isolated from urinary tract infections in Robat karim city.
Material & Methods: In the present Cross-sectional study which was conducted over a period of
6 months, 123 samples of E.coli were collected from Robat karim hospitals for molecular
analysis of TEM genes, causing antibiotic resistance by (PCR) method.Data were
analyzed using SPSS statistical test.
Results: PCR showed that the gene frequency of TEM (80%) and the highest and lowest prevalent of genes were related toTEM in E.coli isolated from urinary tract infections respectively.
Conclusion: According to the high prevalence of resistance to beta-lactam antibiotics, the current study showed that the noted geneTEM play an important role in facilitating the spread of antimicrobial resistance in this region
