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Showing 12 results for Escherichia Coli

Barati L (md), Ghezelsofla F (md), Azarhoush R (phd), Heidari F (bsc), Noora M (bsc),
Volume 13, Issue 3 (9-2011)

Background and Objective: Urinary tract infection is the most common bacterial infection during pregnancy. The pregnant women seems to be at risk for pyelonephritis and untreated infection. Timely recognition and on-time appropriate treatment of urinary tract infection particularly in pregnant women reduce the related complications. This study was done to assesse Sensitivity of isolated E.coli from pregnant women urine to antibiotics. Materials and Methods: In this descriptive study E.coli isolated from 360 urine samples from pregnant women, were examined, using Eosin Methylene Blue, blood sugar method. Antibiogram diffusion disk Kirby-Bauer was performed to assess the antibiotic response. Results: The persent of sensitivity of Escherichia coli to antibiotics were Co-amoxiclav (5.72%), Ampicillin (8.86%), Amoxicillin (11.87%), Cefazolin (32.12), Cephalexin (36.1%), Gentamicin (40.28%), Co-trimoxazole (48.15%), Nalidixic acid (55.3%), Nitrofurantoin (72.48%) and Ceftriaxone (80.78%). Conclusion: This study showed that there is a high level of E.coli antibiotics resistance toward Amoxicillin and Ampicillin high sensevity is related to Ceftriaxone and Nitrofurantoin in this region.
Hafez Ghoran S, Mighani H, Ebrahimi P,
Volume 16, Issue 1 (3-2014)

Background and Objective: The generated genetic diversity in the microbial pathogens and drug resistant led to a growing interest to use herbal medicine. This study was carried out to determine the in vitro anti-bacterial activity of chloroform, ethyl acetate and hydroalcoholic extracts of Scilla persica Hausskn. Methods: In this laboratory study, chloroform, ethyl acetate and hydroalcoholic extracts were obtained from bulb of Scilla persica. The anti-microbial activity, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the extracts were evaluated on Staphylococcus aureus, Bacillus cereus and Escherichia coli using the disk diffusion (growth inhibition zone) and macro-dilution methods. Dimethyl sulfoxide (DMSO) was used as a negative control while nalidixic acid and ampicillin were used as positive control. Results: The maximum inhibition zone for ethyl acetate extract was 26.3±0.1 milimetre, 23.7±0.3 milimetre and 19.5±0.4 milimetre for Staphylococcus, Escherichia coli and Bacillus, respectively. The maximum inhibition zone of chloroform extract was found to be 16.4±0.2 milimetre and 14.9±0.3 milimetre for Staphylococcus and Bacillus, respectively. Conclusion: Antimicrobial activity of the chloroform and ethyl acetate extracts of bulb of Scilla persica on Escherichia coli, Staphylococcus aureus and Bacillus cereus are more effective compared to nalidixic acid and it is similar to ampicillin in in-vitro condition.
Abdi Ha , Rashki A,
Volume 17, Issue 2 (6-2015)

Background and Objective: Uropathogenic strains of Escherichia coli (UPEC) are the most common cause of urinary tract infections. UPEC strains possess an arsenal of virulence factors including fimH, iucD, iroN and hlyA which increase their ability to cause urinary tract infections. This study was done to determine the relationship between phylogenetic group and distribution of virulence genes of Escherichia coli isolated from patients with urinary tract infection. Methods: This descriptive - analytic study was performed on 100 isolates Escherichia coli which collected from patients with UTIs. DNA was extracted from all isolates by the boiling method and subsequently DNA was used to determine the presence of genes encoding virulence factors by Multiplex-PCR. In addition, determination of phylogenetic group, A, B1, B2 and D, was performed by determination of present or absent of of yjaA and chuA genes and DNA fragment TSPE4.C2 using Triple-PCR. Results: The frequency of virulence factors, fimH, iucD, iroN and hlyA were 95%, 69%, 29% and 32%, respectively. In all isolates, the frequency of phylogeny of groups A, B1, B2 and D were 17%, 6%, 55% and 22%, respectively. A significant correlation was found between the presence of virulence encoding genes and the B2 phylogenetic group (P<0.05). Conclusion: Virulence genes were common in phylogenetic group B2 isolates among all phylogenetic groups.
Esfandiari P, Amani J , Imani Fooladi Aa, Forghanifard Mm , Mirhossaini Sa,
Volume 17, Issue 3 (9-2015)

Background and Objective: Enterotoxigenic Escherichia coli (ETEC) are the most common agent which causes diarrhea, worldwide. ETEC is colonized along the cells and then producing heat-labile (LT) and heat-stable enterotoxigenic which enter into intestinal epithelial cells and causes water and electrolyte loss from intestinal epithelial cells and eventually cause diarrhea.This study was done to detect the heat-labile toxin in Enterotoxigenic Escherichia coli using PCR-ELISA technique. Methods: In this descriptive study, DIG-labeled PCR products were bounded to streptoavidin-coated wells of a microtiter plate and detected by anti-DIG–peroxidase conjugate. The biotin-labeled internal probe was used for verification of PCR products. Results: Heat-labile toxin was detected by PCR-ELISA method. The sensitivity of heat-labile toxin was 1.9 ng. This method did not cross-react with bacteria from this variety. Conclusion: PCR-ELISA method is 100 times more sensitive than conventional PCR method and due to lack of agarose gel and electrophoresis device it can be a good alternative to traditional method.
M Razmjoo , P Khaki , V Fadaee Noughani ,
Volume 18, Issue 3 (9-2016)

Background and Objective: The adoption of methods for increasing the shelf life of dairy products by using natural preservatives is necessary. This study was done to determine the antimicrobial activity of aqueous extract of orange peel and its effect on the shelf life of flavored milks.

Methods: In this descriptive –analytical studty the antimicrobial activity of aqueous extract of orange peel was investigated by using disk diffusion method and minimum inhibitory concentration (MIC) by successive dilution of culture broth and then its impact on the shelf life of milk.

Results: In disk diffusion method and MIC the antimicrobial effect of aqueous extract of orange peel was more effective against Staphylococcus aureus and Candida albicans and less effective on Escherichia coli. The growth diameter of disk diffusion method in aqueous extract of orange peel was 7.11, 29.06 and 50 mm for Staphylococcus aureus, Escherichia coli and Candida albicans, respectively. The inhibitory concentration in the aqueous extract of orange peel was 15, 2 and 2 mg/ml, respectively. Also 0.17 g/ml of aqueous extract of orange peel in milk reduced the growth of microorganisms at the time of 6, 12, 24, 48 and 72 hours. Temperature affected the growth of Candida albicans in the milk, so that the growth of microorganisms reduced with decreasing temperature (P<0.05). The growth inhibitory activity of the aqueous extract of orange peel on Staphylococcus aureus was significantly more than on Escherichia coli (P<0.05).

Conclusion: This study showed that the antimicrobial activity of aqueous extract of orange peel on Staphylococcus aureus, Escherichia coli and Candida albicans in vitro and in the milk.

C Halakoo , J Nowroozi , P Pakzad , H Koohsari , M Seyyed ,
Volume 18, Issue 4 (1-2017)

Background and Objective: Water resident bacteria are potentially important reservoir of antibiotic resistance genes. This study was performed to evaluate the antibiotic resistance in Escherichia coli strains isolated from raw waters of Golestan province, northern Iran.

Methods: In this descriptive study, 26 samples from Ziarat river water (13 samples pre & 13 samples post treatment) and 36 samples from Azadshahr area springs water (18 samples pre & 18 samples post treatment) were collected. 75 numbers of Escherichia coli bacterium samples (50 isolated from river and 25 isolated from springs) identified and isolated from raw waters of Golestan province, northern Iran by MPN method via differential tests. Susceptibility of Escherichia coli strains to 11 antibiotics (Amoxicillin / Clavulanic acid, Ampicillin, Imipenem, Cefalotin, Cefotaxime, Gentamicin, Amikacin, Tetracycline, Nalidixic acid, Ciprofloxacin and Trimethoprim / Sulfamethoxazole) was assayed by disk diffusion Kirby & Bauer’s method.

Results: 14 spring's raw water samples and 12 river raw water samples contained Escherichia coli. All of the river and springs samples assayed free from Escherichia coli post treatment. All of the Escherichia coli strains isolated from samples showed the similar phenotypical resistance against to surveyed 11 antibiotics. The most significance resistance to Ampicillin (river 94% & springs 88%), Amoxicillin / Clavulanic acid (river 76% & springs 80%), Tetracycline (river 14% & springs 16%) and Cefalotin (river 8% & springs 16%) viewed. Resistance to Trimethoprim / Sulfamethoxazole (8%), Nalidixic acid (2%) and Ciprofloxacin (2%) just viewed in river samples. All of the river and spring isolates were sensitive to Imipenem, Cefotaxime, Gentamicin and Amikacin and demonstrated intermediate resistance to others antibiotics.

Conclusion: Treatment of raw water from springs and rivers caused the eradication of Escherichia coli. As regard to observed phenotypical resistance in springs’ raw waters, presumably with lack of treatment springs’ raw water can be caused the transmission of antibiotic resistance to human body.

Sm Moosavian , A Rezvanirad ,
Volume 18, Issue 4 (1-2017)

Background and Objective: Extended-Spectrum Beta Lactamase enzymes (ESBLs) are the most important factor for antimicrobial resistance in Enterobacteriaceae The resistance to beta-lactam antibiotics is the main problem in the bacterial infections therapy. This study was done to determine the prevalence of Extended-Spectrum Beta Lactamase enzymes in clinical isolates of Enterobacteriaceae family.

Methods: In this descriptive study, 240 isolates of Enterobacteriaceae family were collected from clinical specimens obtained in Shohada, Rahimi and Madani hospitals in Khorramabad city, Iran. Antibiotic susceptibility of isolates was performed by disk diffusion method. ESBLs production in all isolates was determined using the combination disk method.

Results: Bacteria strains isolated in this study were Escherichia coli (76%), Klebsiella pneumonia (16.2%), Citrobacter (5.4%), Enterobacter spp. (0.83%) and Proteus (1.6%). The results of antimicrobial susceptibility of isolates showed that the highest rate of antibiotic resistance was toward Ampicillin (88%) and Cefotaxime (43%) and the lowest rate was observed to Amikacin (2.5%). According to the results of the phenotypic tests, 141(59%) isolates out of 240 Enterobacteriaceae were beta-lactamase producers.

Conclusion: ESBL producer isolates and antibiotic resistant due to of Enterobacteriaceae isolated from clinical samples from hospitals are high prevalence in Khorramabad city, Iran.

M Ahanjan , Z Morsal-Jahan , B Hashemi , E Nazar , S Ghorbani ,
Volume 18, Issue 4 (1-2017)

Background and Objective: Beta-lactamase enzymes are the most important resistance factors among Gram-negative bacteria to the beta-lactam group of antibiotics. This study was conducted to determine the prevalence of extended-spectrum beta-lactamases (ESBL) in Escherichia coli isolates using PCR method.

Methods: This descriptive – analytic study was conducted on 120 Escherichia coli samples isolated in hospitals in Sari in northern Iran during 2013. Antibiogram was conducted using combined disk method to determine the sample resistance. The presence of β- lactamase gene of CTX-M-15 in ESBL was assessed using PCR method.

Results: Out of 120 Escherichia coli, 98 (81.6%), 15 (12.5%) and 7 (5.8%) bacteria isolated from urinary tract, blood and wound, respectively. Multiple drug resistance were seen in 98% of urine samples, 12.7% of blood samples and 3.6% of wound samples (P<0.05). 18.3% of multiple drug resistance samples were positive for CTX-M-15 β -lactamases resistance gene. The probable presence of CTX-M-15 were detected in blood sample (20%), urine sample and wounds (14.3%) (P<0.05).

Conclusion: Beta-lactamase enzymes were detected in high percent of Escherichia coli isolated from urine samples.

Alisha Akya , Azam Elahi , Roya Chegene Lorestani , Yazdan Hamzavi ,
Volume 20, Issue 4 (1-2019)

Background and Objective: Production of beta-lactamase enzymes is the most common mechanism of bacterial resistance against beta-lactam antibiotics. The aim of this study was to determine the antibiotic resistance pattern and the frequency of AmpC genes in Escherichia coli (E.coli) isolated in outpatients.
Methods: In this descriptive-analytical study, 67 isolates of E.coli were investigated from urinary tract infection of outpatients of the largest medical center in Kermanshah, west of Iran. Their susceptibility to ceftriaxone, cefotaxime, ceftazidime, cefoxitin and imipenem antibiotics was determined using disk diffusion. AmpC phenotypic screening was performed using combination disk method (cefoxitin with and without boronic acid). After extraction the bacterial genome, the presence of MOX, CIT, DHA, ACC, EBC and FOX genes were tested by multiplex PCR.
Results: The resistance of 67 E.coli isolated to ceftriaxone, cefotaxime, ceftazidime and cefoxitin was 49.2%, 49.2%, 37.3% and 25.3%, respectively. The 100% of the isolates were sensitive to imipenem. Seventeen (25.3%) and 9 isolates (13.4%) were phenotypically and genotypically positive for AmpC, respectively. The prevalence of CIT, MOX, FOX, DHA and EBC genes was 7.4%, 5.9%, 4.4%, 4.4% and 2.9%, respectively. However, the ACC gene was not found in isolates. Except for significant correlation between AmpC phenotype and MOX gene (P<0.05), no significant statistical relationship was found between phenotype and AmpC genotype. There was a significant correlation between AmpC phenotype and ceftazidime antibiotic (P<0.05). There was a significant correlation between CIT gene and EBC and FOX (P<0.05).
Conclusion: AmpC-producing E.coli isolates cause significant resistance to cephalosporins. One of the current therapeutic options is using of carbapenems. However, the relatively high prevalence and synergistic genes of AmpC in outpatients are a big concern and unfortunately it reflects the fact that these isolates are prevalent in the society.
Sakineh Yousofvand , Razieh Pourahmad , Saadollah Houshmand ,
Volume 21, Issue 1 (3-2019)

Background and Objective: Ciprofloxacin is effective against a wide range of bacteria, particularly Enterobacteriaceae. However, studies have shown that the resistance of Escherichia coli to ciprofloxacin is enhanced. Thyme is one of the medicinal plants whose essential oil has anti-microbial effects. This study was aimed to investigate the antimicrobial properties of local Thyme essential oil alone and in combination with ciprofloxacin on Escherichia coli mutant strain with intermediate resistance.
Methods: In this descriptive laboratory study, Thyme plants (10 samples) were collected from Lorestan Province, west of Iran during 2016. Theses samples belonged to T. eriocali species. Plant essential oil was extracted by distillation method with Clevenger equipment. The antimicrobial properties of local thyme were determined by measuring minimum inhibitory concentration (MIC) of it alone and in combination with ciprofloxacin using sequential dilution method (macrodilution and microdilution methods) in Escherichia coli strains. Minimum bactericidal concentration (MBC) was measured by cultivation method. The interaction between essential oil and ciprofloxacin was determined by calculation of fractional inhibitory concentration index (FICI).
Results: MIC of essential oil for wild type strain MG1655 and mutant strain RE6 was 8 and 10 µl/ml, respectively. MBC was equal to MIC. 0.4 µl/ml of essential oil decreased 45 fold the MIC of ciprofloxacin in mutant strain and produced synergistic interaction (FICI=0.06).
Conclusion: Thyme essential oil in concentration less than its MIC in combination with ciprofloxacin via synergistic interaction reduces antibiotic MIC and antibiotic resistance.
Mohammad Mehdi Soltan Dallal , Omolbanin Biglari, Zahra Rajabi, Mohammad Kazem Sharifi Yazdi , Abbas Rahimi Foroushani , Shabnam Haghighat Khajavi ,
Volume 23, Issue 1 (4-2021)

Background and Objective: The most common enterohemorrhagic Escherichia coli strain is the O157: H7 serotype, which is one of the most important intestinal pathogens and can cause complications such as hemorrhagic colitis, hemolytic uremic syndrome and acute renal failure. The aim of this study was to evaluate the enterohemorrhagic Escherichia coli causing molecular outbreaks of foodborne illness in Iran.
Methods: In this descriptive cross-sectional study, 189 fecal swab specimens were examined during April to September 2018. All suspected isolates were tested for biochemical tests. The isolates were confirmed by molecular PCR and evaluated by antimicrobial susceptibility tests.
Results: From 189 stool swab samples studied, 98 Escherichia coli isolates were detected based on phenotypic tests. Most of the outbreaks occurred in summer and the prevalence of enterohemorrhagic Escherichia coli was 24.5%, which 4% of them were non-O157H7. Most patients were between 1 and 12 years of age and the highest antibiotic resistance to cotrimoxazole and chloramphenicol was observed at 80% and 79%, respectively.
Conclusion: This study showed an increase in enterohemorrhagic Escherichia coli with 24.5% and an increase in antibiotic resistance to the antibiotics of chloramphenicol, cotrimoxazole and carbapenems. Increased resistance to imipenem and meropenem antibiotics makes it difficult to treat beta-lactamase-resistant strains.

Minoo Akbari , Ali Hossein Rezayan , Hossein Rastegar, Mahmoud Alebouyeh ,
Volume 23, Issue 4 (1-2022)

Background and Objective: Binding of antibiotics to nanoparticles increases the antibacterial potential of nanoparticles and antibiotics. This study was performed to determine the antibacterial and hemolytic effect of zinc / ferrite / cellulose nanocomposite (ZnFe2O4 @ Cell) (single nanoparticle), zinc / ferrite / cellulose nanocomposite was aminated with 3-aminopropyltriethoxysilane (APTES) with the name of ZnFe2O4@Cell@APTES (Coated nanocomposite) and ZnFe2O4@Cell@APTES@Van nanocomposite (coated nanocomposite bound to vancomycin) against gram-negative bacteria Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and gram-positive bacterium Staphylococcus aureus (S. aureus).
Methods: In this descriptive study, antibacterial-activity was evaluated by broth macro dilution method. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MBC) were determined for E. coli, S. aurous and P. aeruginosa. The hemolytic activity of nanoparticles was investigated by colorimetric method.
Results: Nanoparticles did not have hemolytic activity. ZnFe2O4@Cell and ZnFe2O4@Cell@APTES@Van did not have a significant antibacterial effect against gram-positive and gram-negative bacteria, and vancomycin binding resulted in antibacterial-activity. ZnFe2O4@Cell@APTES@Van inhibited the growth of Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. The growth of E. coli was reduced to 85% at a concentration of 0.4 mg/ml and a concentration of 0.1 mg nanoparticles completely prevented the growth of P. aeruginosa. The growth of gram-positive S. aureus bacteria at a concentration of 0.3 mg/ml nanoparticles was completely stopped.
Conclusion: Vancomycin-modified nanocomposite has antibacterial-activity against both gram-positive and gram-negative bacteria and has the potential to overcome the antibiotic resistance of bacteria.

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مجله علمی دانشگاه علوم پزشکی گرگان Journal of Gorgan University of Medical Sciences
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