Showing 11 results for Escherichia Coli
Hamid Abtahi, Ghasem Mosayebi, Ali Hatef Soleimanian,
Volume 10, Issue 3 (6-2007)
Abstract
Introduction: Streptolysin O (SLO) is an antigenic protein that is secreted by Streptococcus pyogenes. Streptococcal infections are diagnosed with anti streptolysin O. At present, streptolysin O is produced by vectors that have fusion protein. In this study streptolysin O without fusion protein vectors is produced. Materials and Methods: In this experimental study, Streptolysin O gene was amplified by Polymerase chain reaction (PCR) method and subcloned to prokaryotic expression vector pET28a. Escherichia coli BL21-DE3-plySs were transformed with pET28a-SLO and gene expression was induced by IPTG. Then it was purified by Ni-NTA kit. The concentration of SLO was assayed by Bradford method. To confirm recombinant SLO Western Blot was used. Results: The sequencing result was confirmed by Sanger method and was the same as SLO gene. Escherichia coli BL21 (DE3) pLysS was transformed with pET28a-SLO and gene expression was induced by IPTG. The expressed protein was purified by affinity chromatography with Ni-NTA resin. The concentration of purified protein was 100µg/ml. The integrity of product was confirmed by Western Blot analysis using a mouse anti streptolysin O. Conclusion: Data showed that recombinant SLO protein can be produced by pET28a in Escherichia coli. This protein maintains its antigenic effect very well. Therefore, recombinant SLO has same epitopes with natural form of this antigen.
Majid Eslami, Shahin Najar Peerayeh,
Volume 15, Issue 1 (4-2012)
Abstract
Background: TEM, PER, and VEB are extended-spectrum betalactamase (ESBL) enzymes that are capable of hydrolyzing penicillins, cephalosporins, and aztreonam. The aim of this study was to determine the prevalence of ESBL producing E.coli and molecular evaluation of TEM, PER, and VEB β-lactamases among E.coli strains.
Materials and Methods: A total of 200 clinical strains of E.coli were isolated from clinical specimens and their antibiotic susceptibility was determined by disk diffusion method. ESBL production was determined using the combined disk method with CAZ and CTX with clavulanic acid and alone. Minimum concentration inhibition (MIC) for CAZ and CTX with clavulanic acid and alone was determined by agar dilution method. Finally, PCR with specific primers was used for determining the presence of blaTEM, blaPER, and blaVEB genes.
Results: Combined disk method confirmed 94 strains (47%) to be ESBL producing E.coli. Of the 94 ESBL producing strains, 36 samples had MIC=16, 44 samples had MIC between 32-256, and 10 samples had MIC≥512 for ceftazidime, whereas 8 samples had MIC=16, 68 samples had MIC between 32-256, and 21 samples had MIC≥512 for cefotaxime. The frequency of TEM was 44% however, blaPER and blaVEB genes were not detected by PCR among ESBL producing isolates.
Conclusion:The results indicated that the high percentage of ESBL producing E.coli is 47% and PCR method showed a high frequency of TEM enzyme, but PER and VEB betalactamase were not found among them.
Raziyeh Khalesi, Jafar Salimian, Shahram Nazarian, Zahra Ehsaei , Ali Asghar Rahimi, Nafiseh Amini, Seyed Mohammad Moazzeni,
Volume 15, Issue 1 (4-2012)
Abstract
Background: Enterotoxigenic Escherichia coli bacterium is the most important bacterial agent causing diarrhea. Specific virulence factors, such as enterotoxins and colonization factors, distinguish ETEC from other classes of diarrheagenic E.coli. In this study, heat-labile toxin was purified which could be utilized for anti-toxin assay in GM1 gangelioside receptor-ELISA based method and for identification of ETEC producing toxin.
Materials and Methods: In this experimental study, bacterial strain producing heat-labile toxin was first cultivated for production and purification of toxin. Then supernatant soluble proteins were precipitated with ammonium sulfate and purified using biochemical methods. Finally, purified protein was dialyzed against Tris 0.02 mM pH 8 and analyzed on gel electrophoresis. GM1 gangelioside receptor-ELISA based method was used for detection and assessment of the purified toxin. Through this method, the effect of anti-recombinant heat-labile toxin B subunit neutralization on heat-labile toxin was investigated.
Results: Toxin purification was revealed by the presence of 12 and 28 KD protein bands. This study demonstrated that anti-recombinant heat-labile toxin B subunit antibody can detect the purified toxin and can inhibit its binding to GM1 receptor up to 80%.
Conclusion: Purification of heat-labile toxin and gangelioside receptor-ELISA assay can be used for accurate detection and epidemiological study of clinical isolates.
Mohammad Reza Massoudinejad, Ashraf Mazaheri Tehrani, Farshid Ghanbari, Simindokht Mirshafian,
Volume 17, Issue 3 (6-2014)
Abstract
Background: The conventional methods of water disinfection are chemical process, ozonation, UV radiation, membrane processes and etc. In recent years, electrolysis method has been considered that is a green process with high efficiency and not by-products. The aim of study is evaluation of efficiency of the electrolysis process with continuous flow in the disinfection of water contaminated with fecal coliform.
Materials and Methods: This study is a Descriptive - analytical study. The samples are prepared in three groups by adding domestic wastewater, manure and E.Coli colonies to distilled water. The prepared samples were introduced to continuous electrochemical reactor. The removal efficiency of electrolysis process was investigated in different conditions which include electrode material (copper and graphite compressed), reaction time (40, 50, 60 and 70 minutes), voltage 48V, distance of electrode 5 cm and the initial pH 7.
Results: The results indicate that removal efficiency depends on source of pollutant, reaction time, and type of electrode. Also the optimal efficiency for E.Coli colonies achieved in electrolysis instrument was as follows: electrode material = copper electrode, distance of electrode=5cm, applied voltage= 48V and reaction time=70 minute. Under these conditions removal efficiency was obtained 99%. No significant changes in pH, TDS and EC in different times and coliform bacteria were not created by changing the source.
Conclusion: According to the results of this study, using the electrolysis process with continuous flow, as a convenient method with high performance and environmentally, suggest for the disin fecting the water contaminated with fecal Coliform.
Maryam Sadrnia, Mohammad Arjomandzadegan,
Volume 17, Issue 6 (9-2014)
Abstract
Background: Nowadays, with the development of drug resistance, the use of herbs as an alternative to chemical drugs is considered by researchers. In this work, effects of Aloe vera extracts on clinical isolates was studied.
Materials and Methods: Aloe vera plant medicinal plants were obtained from a greenhouse. Three extracts including essential oils, extracts and no essential oils and essential oil extraction method also includes a complete extract of Aloe vera were prepared Percolation total. To investigate Microbiology extracts of two strains of Staphylococcus aureus and Staphylococcus epidermidis clinical strain of Gram-positive and Gram-negative isolates of Klebsiella pneumoniae and Escherichia coli strains Staphylococcus aureus ATCC25923 were used as well. Evaluate the effect of two methods: Kirby-Bauer disk with the minimum inhibitory concentration (MIC) was performed using microplate dilution. Turbidity was determined by an ELISA reader apparatus.
Results: All extracts of aloe vera on Klebsiella with a diameter of 32±2 mm mg/ml 285.7 concentration with microplate dilution method was 2.23 mg/ml. Staphylococcus aureus and MIC zone diameter of 30±2 mm and mg/ml 2.23, Staphylococcus epidermidis and Escherichia coli mg/ml4.46 mm 17.85 mm 30±5 mg/ml 17.85 respectively. Similar concentration of 17.85 mg ml Aloe Vera with a circle formed by the disk mc/ml 10 gentamicin was shown. This effect is similar to other bacteria antibiotics gentamicin, clindamycin, erythromycin, and Cefixime compared with Aloe Vera extract has been proven. Essential oils made from all parts of the same whole extract of aloe vera, but not essential extracts, bacteria studied were ineffective.
Conclusion: In this study the effects of similarity and some excess water Asrsarh Aloe Vera with common antibiotics on bacteria causing the infection was confirmed. Therefore, by production of appropriate pharmaceutical plant drugs with fewer side effects, bacterial infections couled be treated properly.
Hossein Morsali, Golnaz I Asaadi Tehran, Hanieh Asaadi, Sajjad Yazdansetad, Reza Najafpour,
Volume 20, Issue 6 (9-2017)
Abstract
Abstract
Background: Salmonella spp. and Escherichia coli O157:H7 are the most common bacterial foodborne pathogens contaminating food products especially meat. It is essential to detect the pathogens rapidly, specifically, and simultaneously by selection and optimization of suitable reference genes. The present study was conducted to simultaneously detect E. coli O157:H7 and Salmonella spp. in meat products and contamination prevalence assay by using multiplex PCR based on rfbE and invA genes amplification in Zanjan province, northwest of Iran.
Materials and Methods: A total of 74 meat samples were obtained from various regions of Zanjan province, randomly. 25 grams of each meat sample was completely homogenized in 225 ml of Mueller-Hinton broth growth medium and incubated. Bacterial strains were purified and DNA extraction was performed from purified bacterial isolates. Simultaneous amplification of rfbE and invA gene fragments was done with specific primers by optimization of a multiplex PCR. Finally, the sensitivity of the method was evaluated by inoculation of the bacteria to the meat.
Results: Out of 74 meat samples, 6(8%), 4(5.4%), and 2(2.7%) samples were positive for E. coli O157:H7, Salmonella, and both E. coli O157:H7-Salmonella, respectively. Multiplex PCR indicated high sensitivity for simultaneous detection of the pathogens in lowest dilution of the bacteria that had been inoculated to the meat.
Conclusion: In this study, a multiplex PCR was optimized based on Salmonella spp. and E. coli O157:H7 virulence genes for rapid and simultaneous detection of the pathogens with high sensitivity and specificity. Multiplex PCR as a reliable tool for rapid and simultaneous detection of foodborne pathogens to prevent contamination of food products.
Maryam Doosti Mohajer, Hamid Pajavand, Ramin Abiri, Amirhooshang Alvandi,
Volume 20, Issue 9 (12-2017)
Abstract
Abstract
Background: Antibiotic resistance rates in E. coli are rapidly rising, especially with regard to fluoroquinolones. One of the mechanisms that lead to antibiotic resistance is efflux pumps. The aim of this study was phonotypic and genotypic analysis of efflux pump role in fluoroquinolones resistance of E. coli strains isolated from hospitalized patients in Kermanshah 2013.
Materials and Methods: In this cross-sectional study, 100 isolates of E. coli were collected from hospitalized patients from Kermanshah. All isolates were identified by standard biochemical tests. The antimicrobial susceptibility patterns were determined by disk diffusion method according to CLSI guidelines. The presence of Efflux pump genes was determined by a PCR method.
Results: The rates of resistance to Ceftazidime, Nalidixic Acid, Ciprofloxacin, Norfloxacin, Ofloxacin, Gentamicin, and Tetracycline were 73%, 67%, 55%, 54%, 45%, 38%, and 24%, respectively. According to the results of PCR test, of 100 E. coli isolates, 99% of isolates were positive for acrA, 98% for acrB, 95% for acrE, 98% for acrF, 94% for mdfA, 96% for norE, and 96% for tolC.
Conclusion: In Strains with positive gene acrA, acrB, acrA, acrB, tolC, mdfA, norE, the presence of efflux pump inhibitor reduced the amount of resistance to antibiotics. So, efflux pumps are important in antibiotic resistance.
Pooneh Roghanian, Jafar Amani, Shoreh Zare, Zahra Nour Mohammadi,
Volume 22, Issue 1 (4-2019)
Abstract
Background and Aim: Enterotoxigenic Escherichia coli (ETEC) is one of the most common bacterial causes of diarrhea deaths among children and travelers in developing countries. The ETEC colonization factors, such as CFA/I and CS2 play an important role in the development of the disease. In this study, to produce the CFaE fusion recombinant protein, the tip subunits CFA/I(CfaE) and sub structural unit of CS2 (CotD) from ETEC, were used. Since mucosal immune responses to CFs can prevent disease, the aim of this study was to develop a chimeric antigen for developing the effective vaccine.
Materials and Methods: In order to amplify the cfae-cotd gene, a dual gene construct consisting of cfae and cotd, the PCR reaction was performed by designed primers. The propagated gene was cloned in the expression vector pET28a. Following the induction of a recombinant gene construct with IPTG, the recombinant protein was expressed and purified by Ni-NTA chromatography column and confirmed by western blotting by Anti-Histag.
Ethical Considerations: This study with research ethics code IR.IAU.SRB.REC.1397.066 has been approved by research ethics committee at Islamic Azad University, Science and Research Branch of Tehran, Iran.
Findings: Cloning accuracy was confirmed by PCR and enzyme digestion reaction. The presence of the band in the SDS-PAGE 10% gel in the 68 kDa region, the expression of the recombinant protein, and the presence of the band on the nitrocellulose paper in the Western blotting test confirmed the production of recombinant protein.
Conclusion: Optimization of codon and expression in heterologous hosts is a useful method for the production of recombinant proteins. The production of ETEC antigens as a candidate for vaccination against this bacterium is also prominent.
Maryam Ghane, Fariba Adham,
Volume 22, Issue 6 (1-2020)
Abstract
Background and Aim: recent years, increase in extended-spectrum β-lactamases (ESBLs) producing Escherichia coli has led to limitations of treatment options. This study aimed to find the frequency of blaTEM and blaPER genes among ESBL producing urinary isolates of E. coli and detect their resistance pattern.
Methods & Materials: From January 2016 to February 2017, 972 urine samples from patients suspected of having urinary tract infections in three main hospitals and laboratories in Karaj were collected. Bacterial identification, antimicrobial susceptibility and ESBL production were performed according to the standard guidelines. Polymerase chain reaction was used for the detection of TEM and PER -lactamases.
Ethical Considerations: This study was approved by the Research Ethics Committee of Islamic Azad University of Tehran Medical Branch (Code: IR.IAU.TMU.REC.1396.274).
Results: Out of 972 samples, 500 cases were culture-positive for E. coli. Thirty-six percent (n =180) of the isolates were determined as ESBL-producer. Among ESBL positive isolates, the most susceptibility was observed in amikacin and imipenem (80 and 60% respectively). Resistance to trimethoprim/sulfamethoxazole,ciprofloxacin, tetracycline and gentamicin was 92.7%, 78.9%, 66.1% and 57.8%, respectively. All ESBL producers exhibited multidrug resistance. Among the ESBL-positive isolates, blaTEM gene was detected in 44.72% (n=85) of the isolates, but the blaPER gene was not found in any of the isolates.
Conclusion: The prevalence of multidrug resistant ESBLs producing uropatogenic E. coli is high. Continues monitoring of ESBL producers and their resistance patterns can help to reduce the spread of such resistant strains in the community.
Ali Moradpoor Shamami, Dr Masumeh Anvari, Seyedeh Tooba Shafighi, Hadi Sedigh Ebrahim-Saraie,
Volume 25, Issue 5 (12-2022)
Abstract
Introduction: Considering the importance of urinary tract infections caused by uropathogenic Escherichia coli (UPEC) in the medical field, this study aimed to investigate serogroups O25 and O16 and the pattern of antibiotic resistance among UPEC isolates obtained from hospitalized patients with urinary tract infections (UTIs) in Rasht hospitals.
Methods: A total of 110 urine samples were collected from patients with UTIs referred to selected hospitals in Rasht. The disk diffusion method, as recommended by the CLSI, was used to determine the pattern of antibiotic susceptibility. Serogroups O25 and O16 were detected using specific primers.
Results: Among the studied samples, 36.4% (40/110) were men and 63.6% (70/110) were women. Based on the antibiotic susceptibility pattern, a high level of antibiotic resistance was observed against nalidixic acid (81.8%) and co-trimoxazole (78.2%), while the most effective antibiotics were amikacin (85.5%) and nitrofurantoin (83.6%). In addition, multi-drug resistant phenotype was found in 72.7% (110/80) of UPEC isolates. According to PCR results, the frequency of serogroups O25 and O16 was 36.4% and 17.3%, respectively. Both serogroups had the highest resistance to nalidixic acid and co-trimoxazole, while the lowest resistance in serogroup O25 to nitrofurantoin (20%) and amikacin (14.3%) and in serogroup O16 to imipenem (5.3%) and nitrofurantoin (10.5%).
Conclusions: This study showed that the high prevalence of MDR strains among UPEC strains is very worrying and professionals should be very careful in prescribing antibiotics for patients. Like most studies, the frequency of serogroup O25 was high, and probably, this serogroup can play a role in causing urinary tract infections and antibiotic resistance of UPEC strains.
Ensiyeh Abbaspour Naderi, Mohammad Ali Bepouei, Mahzad Diar, Matin Mohamadi, Mohammad Hedayati, Mahdi Shahriarinour,
Volume 26, Issue 4 (11-2023)
Abstract
Introduction: Urinary tract infection (UTI) is one of the most important and common infections in children. The aim of this study was to investigate the frequency of qnrB and qnrS genes in Escherichia coli and Klebsiella pneumoniae isolated from urinary tract infections of children in 17 Shahrivar Hospital in Rasht.
Materials and methods: In this descriptive cross-sectional study, 49 strains of Escherichia coli and Klebsiella pneumoniae were isolated from 17 Shahrivar Hospital in Rasht and identified using biochemical methods. Sensitivity and resistance of strains to antibiotics were determined by Kirby Bohr and dilution broth methods. PCR method was used to evaluate the frequency of qnrS and qnrB genes in isolates.
Results: In this study, the highest resistance was observed in piperacillin (81.5%) and cefazolin (88.9%) isolates from Escherichia coli and in Klebsiella pneumoniae (cefazolin (90.9%) and amoxicillin (95.5%) isolates from 49 Isolated, 73.4% had qnrB gene and 97.9% had qnrS gene.
Conclusion: It seems that one of the reasons for increasing multidrug resistance in hospital isolates of urinary tract infection (UTI) in Rasht is the increased transfer of plasmid genes between these isolates.
