Showing 28 results for Escherichia Coli
H Hoseinzadegan, A Hassani, M Azadpoor, S Soleimannezhad, F Mohamadi,
Volume 1, Issue 2 (10-2007)
Abstract
Abstract
Background and objectives:
(ESBL) strain is one of the emerging health related problems in the world recently.
Some of the species of the gram-negative bacilli including Klebsiella Pneumonia &
Escherichia Coli are well known ESBL producing among bacteria, and they cause
uncontrollable infections. This Cross-sectional study was designed to asses the
ESBL producing gram negative bacilli among inpatients of Shohada-ye- ashayer
hospital (Khorram Abad).
Extended Spectrum Betalactamase producing
Materials and methods:
methods. ESBL producing gram negative bacilli were screened with MacConkey
Agars containing 4 mg/liter Ceftazidime and confirmed with double disk synergy
method as recommended by national standard laboratory institute.
Samples were processed with routine laboratory
Results:
positive for ESBL.The most isolated species of ESBL are 20 Klebsiella
pneumonia(8.88%), 10 Escherchiia coli(4.44%) and 10 pseudomonas
aeruginosa(4.44%). The most ESBL producing gram-negative bacilli were Isolated
from urine samples (21 cases 39.62%).and Ten cases (18.86%) from bronchoscopy
sterile samples.
Fifty- there cases (23.55%) of 225 total isolated gram negative bacilli are
Conclusion:
frequently isolated from Shohada-ye-Ashaier Hospital. Regarding the high
resistance of these strains against many of the antibiotics and even against
Carbapenems, health- care providers need to plan controlling policies for such
strains.
The Results indicate that ESBL producing gram-negative bacilli are
Key words:
Extended Spectrum Betalactamase.
Hospital acquired infection, Escherichia coli, Klebsiella Pneumoniae,
M Pourhossein, I.s Roberts,
Volume 2, Issue 1 (4-2008)
Abstract
Abstract
Background and objectives:
important virulence factor for many invasive bacterial pathogens of humans.
Escherichia coli offer a model system to study the mechanisms by which
capsular polysaccharides are synthesized and exported onto the cell surface of
bacteria. Biosynthesis of the E
consists of the repeat structure -4) GlcA- (1, 4)-GlcNAc- (1-, requires the
KfiA, KfiB, KfiC, and KfiD proteins. Until now , the role of all proteins
except KfiB have been kown.
Capsular polysaccharide expression is an. coli K5 capsular polysaccharide, which
Material and Methods
(pMA1) and several derivatives of KfiB expression construct (pMA2-6) were
made with a 6Xhis-tag at the N-terminus. The presence of the hexa histidin tag
facilitated purification of the KfiB protein using Ni
: To study the role of the KfiB protein, a full-length2+-NTA chromatography.
Results:
pPC6::23 and restore capsule production. Successful complementation by
pMA1, showed that the fused hexa-histidine tag did not interrupt the function
of KfiB and that the full-length KfiB is required for complementation.
All plasmids except pMA1 failed to complement the mutation in
Roberts, I.S.
Conclusion:
cytoplasmic membrane.
Localization studies revealed that KfiB is associated with the
Key words:
Escherichia coli, Capsular polysaccharide, KfiB, K5
Mm Soltan Dallal, M Hosseini, Tp Abedi Mohtaseb, A Tabatabaei Bafroei,
Volume 3, Issue 2 (10-2009)
Abstract
Abstract Background and objectives: Water-born diseases are typically caused by pathogens transmitted by orofecal way. Because it is no practical and no economical and also it is time-consuming to find water-born pathogens in water reservoirs, the laboratory studies are performed on the basis of indicator microorganism. Escherichia coli is considered as the most important indicator bacterium for water monitoring. The aim of this study was to evaluate the three methods of Pour Plate (PP), Most Probable Number (MPN) and Membrane Filter (MF) in isolation of Escherichia coli in well water of Parks. Material and Methods: One hundred and sixty five samples of well water, from five geographical zones of north, south, east, west and center of Tehran, were taken in a sterile condition and sent to microbiology department of health faculty to assess with three methods of PP, MPN and MF. The results were analyzed by chi-square. Results: The results indicate that 90 water samples (54.5%) aren’t health. The samples taken from south of Tehran are most contaminant than other zones. The highest contaminated Samples (54.5%) are related to membrane filtration method in comparison with MPN (34.5%) and PP (27.3%). Conclusion: Since the MF method can recognize the contaminants quickly and effectively, we recommend it more. Based on these results, it is essential to educate children not to drink well water in parks. Keywords: well water contamination, Escherichia coli, Tehran's parks
Mahsa Yazdi, Ali Nazemi, Mir Saed Mir Nargasi, Mr Khataminejad, Sh Sharifi, M Babai Kochkaksaraei,
Volume 4, Issue 1 (4-2010)
Abstract
Abstract Background and objectives: Beta-lactamase enzymes are the most causes of resistance to antibiotics among gram-negative bacteria. Nowadays, Infections due to ESBLs are being increased throughout the world and is considered as a new burden to the health systems. This study aimed at determining the sensitivity pattern of E.coli isolates to beta-lactam antibiotics, and investigating the presence of blaCTX-M, blaTEM, and blaSHV genes in the urine samples. . Material and Methods: In this study, 244 E.coli isolates were screened in 2009-2010. The antibiotic susceptibility of E. coli isolates were determined by disc-diffusion method. Antimicrobial agents tested were cefoxatime, ceftazidime, imipenem, nalidixic acid, and ciprofloxacin. The combined disc test was used to confirm the results. The results were compared to the Clinical and Laboratory Standards Institute (CLSI) and ESBL positive isolates were further investigated for the presence of blaCTX-M, blaTEM, and blaSHV genes by PCR. Results: Of 244 E. coli isolates, 116 (47.1%) are resistant to Ceftazidime, and 96 (39.2%) to cefoxatime. Also, 109 (44.3%) isolates are ESBL positive. blaCTX-M, blaTEM, and blaSHV genes are found among 95 (87.1%), 75 (68.8%), and 77 (70.6%) ESBL positive isolates, respectively. Forty (36.6%) isolates have all three genes, while 68 (62.3%) include blaTEM and blaSHV genes. Moreover, 61 (55.9%) isolates carry blaCTX-M and blaTEM genes, and 54(49.5%) have blactx-M and blashv. Conclusion: Regarding the high frequency of resistance to the third generation cephalosporin antibiotics, precise antibiogram testing is highly recommended before any antibiotic prescription in cases of infections with ESBL producing microorganisms. Key words: ESBL Escherichia coli blaCTX-M blaTEM blaSHV.
R Esmaeili, Ma Amir-Zargar, M Nazari, M Alikhan,
Volume 7, Issue 5 (2-2014)
Abstract
Abstract
Background and Objective: Urinary tract infections and bacteremia are the major problems in renal transplant patients, which are mostly due to immunesuppressive regimens, surgery, and exposure to the germs in hospital. The aim of this study was to determine the prevalence of bacterial agents in the blood and urine samples of kidney transplant candidates.
Material and Methods: In this one-year-long study, thirty-three renal transplant candidates were assessed for urine and blood cultures. One urine and blood samples from each patient before transplantation and three samples after transplantation were collected. The Samples, using standard microbiological methods, were investigated and infectious organisms identified.
Results: In 133 urine samples, Escherichia coli (20.5%), Enterobacter spp. (5.3%), Klebsiella spp. (3 %) and Staphylococcus epidermidis (1.5%) were isolated. In the blood samples, Enterobacter spp. (9.1%), Escherichia coli (6.8%), Staphylococcus epidermidis (3.8%) and Klebsiella spp. (0.8%) were isolated.
Conclusion: The results indicate that urinary tract infection was high in patients with transplanted kidney, and E. coli is the most common cause of this infection.
Keywords: Kidney Transplantation Bacterial infections Urinary Tract and Blood Infections Escherichia Coli
T Ghelich, M Hashemi Karouei, I Gholampor Azizi,
Volume 8, Issue 2 (7-2014)
Abstract
Abstract Background and Objective: Because of increased resistance to antibiotics, side effects of chemical drugs and importance of medicinal plants, we aimed to assess the antibacterial effects of methanolic extract of the Polygonumbistorta plant on the E. coli (ATCC 15224), Ps. aeruginosa (ATCC 25619), B. subtilis (ATCC 6633) and Stap. Aureus (ATCC 25923). Material and Methods: After preparing the extract, its antibacterial effect was assessed via gel diffusion method, using disk / well diffusion methods to determine MIC and MBC Results: MIC of methanolic extract was 78 µg/ml for E. coli, 63×103 µg/ml for Pseudomonas aeruginosa, 39 µg/ml for Bacillus subtilis and 31×102 µg/ml for Staphylococcus aureus Conclusion: In spite of resistance of gram-negative bacteria to chemical agents, polygonum bistorta methanolic extract could inhibit the growth of E.coli and P. aeruginosa. Key words: Antibacterial, Bistorta, Escherichia Coli, Pseudomonas Aeruginosa
Gh Goudarzi, P Msc of Microbiology, Department of Microbiology, School of Medicine, Lorestan University of Medical, M Lashkarara,
Volume 8, Issue 3 (8-2014)
Abstract
Abstract Background and Objective: Escherichia coli, one of the most common causative agents of urinary tract infections (UTIs) acquired from community and hospital, has developed multiple resistances to various antibiotics such as aminoglycosides. The main resistance mechanism to aminoglycosides is inactivation of these drugs by a variety of acetyltransferase, nucleotidyltransferase, and phosphotransferase enzymes. this study aimed to assess the prevalence of resistance to some important aminoglycosides as well as the distribution of aph(3)-Ia, aac(3)-IIa and ant(2)-Ia genes among uropathogenic Escherichia coli isolates obtained from patients suffering UTIs. Material and Methods: Using the disk diffusion method, the antimicrobial susceptibility of 200 uropathogenic E. coli isolates collected from outpatients and inpatients was investigated to nine antibiotics. Then, the distribution of aac (3)-IIa, aph (3)-IA and ant (2)-IA genes was determined by PCR method. Results: Thirty-nine percent of E.coli isolates obtained from inpatients (n=100) and 19% of those from outpatient (n=100) demonstrated resistance to at least one of the tested aminoglycosides (i.e. 58 isolates). Among the isolates examined (n=200), 19.5%, 13%, 7.5% and 4.5% were resistant to gentamicin, kanamycin, neomycin and amikacin, respectively. The most prevalent gene among the strains resistance to at least one of the aminoglycosides (n=58) was aac (3)-IIa (65.5%), followed by aph (3)-IA (25.8%). Also, the ant (2)-IA gene was not seen in any isolates. Conclusion: The presence of aac (3)-IIa gene is significantly associated with gentamicin resistance (100%, p<0.05). Because of relatively high distribution of the aac (3)-IIa gene among uropathogenic E.coli, the use of aminoglycosides such as amikacin to treat UTI in clinical setting is recommended. Keywords: Escherichia Coli, Urinary Tract Infections, Aminoglycoside-Modifying Enzymes (AMEs)
Sedighi, I, Alikhani, My, Nakhaee, S, Karami, P,
Volume 8, Issue 4 (1-2015)
Abstract
Abstract Background and Objective: Escherichia coli is the most common cause of urinary tract infections in children and the leading cause of intra-abdominal infections (peritonitis and abscess) followed intestinal injuries. Urinary tract infection, including cystitis and pyelonephritis, is a common childhood infection. E. coli causes more than 90 percent of the community acquired and 50% of hospital acquired urinary tract infections therefore, the determination of E. coli antibiotic susceptibility is a paramount importance to clinical and epidemiological purposes. Material and Methods: In this cross-sectional study, 50 E. coli strains isolated from urine samples of children less than 7 years of age with urinary tract infections. They were compared for drug susceptibility testing by disc diffusion method with 50 strains of Escherichia coli isolated from stool samples of healthy children with the same age and sex pattern. Results: The actual amount of drug sensitivity of uropathogenic and intestinal Escherichia coli strains to amikacin was 94 and 100%, nitrofurantoin 90 and 88%, gentamicin 66 and 94%, cefixime 56 and 60%, nalidixic acid 38 and 44% and to cotrimoxazole 28 and 32%, respectively. Conclusion: the rate of resistance to gentamicin, Cefixime and nalidixic acid in urinary tract infection isolates were more than intestinal strains. The highest rate of drug resistance in urinary Escherichia coli isolates was associated with cotrimoxazole and the lowest one with amikacin. Keywords: Escherichia Coli, Intra-Abdominal Infection, Drug Resistance, Urinary Tract Infection, Children
Gharahjeh, S, Nowzari, A, Azarhoush, R, Fuladi Nejad, M, Nematollahi, N, Aryaei, M, Mohammadi, R,
Volume 9, Issue 2 (7-2015)
Abstract
Background and Objective: Neonatal sepsis is a remarkable factor in mortality, morbidity, neonatal and perinatal complications. Group B Streptococcus (GBS) is the primary cause of invasive disease in infants and pregnant women. This study aimed to determine the relationship between antimicrobial resistance of the bacteria colonized in the vagina and rectum of pregnant women and early neonatal infection.
Material and Methods: In this prospective study conducted on 282 pregnant women, bacterial sensitivity to ampicillin, cefazolin, erythromycin, vancomycin, gentamicin, amikacin was measured. Furthermore, the relationship between rectal and vaginal colonization of mothers and early neonatal sepsis was evaluated.
Results: Of 98 positive rectal cultures, 49 (50%) were Gram-positive cocci and 49 (50%) E.coli. of 143 positive vaginal cultures, 136 (95.1%) were Gram-positive cocci, 7 (4.9%) were E.coli and two were positive GBS. We could find definitive neonatal sepsis. Significant correlation was found between a history of urinary tract infection and the mother's positive rectal culture (P =0. 03).
Conclusion: Clinical sepsis in neonates is correlated with positive rectal culture (P =0. 001) and the positive E.coli vaginal cultures is associated with suspected neonatal sepsis (P =0.007). Gram-positive cocci were resistance to ampicillin and gentamicin, and E.coli was resistant to ampicillin, erythromycin and vancomycin. Because of resistance to ampicillin, we recommend cefazolin due to its sensitivity to organisms and safety in pregnancy.
Kargar, M, Kargar, M, Zareian Jahromi, M,
Volume 9, Issue 3 (9-2015)
Abstract
Abstract
Background and Objective: Escherichia coli O157:H7 is one of the most well-known pathogenic bacteria worldwide that can develop severe diseases such as hemolytic uremic syndrome (HUS). This study aimed to assess the prevalence of virulence genes of E. coli O157:H7 in patients with suspected urinary tract infections (UTIs).
Material and Methods: This cross-sectional study was conducted on 10,372 urine samples collected from patients with suspected UTI from six hospitals and clinical laboratories in Shiraz city. CT-SMAC medium, b-glucosidase activity test (MUG), specific antiserum, and the presence of O157 and H7 genes by PCR were used to confirm E. coli O157:H7 isolates. Then, stx1, stx2, eaeA, and hlyA genes were evaluated using multiplex PCR.
Results: In this study, 16 (7.8%) and 13 (6.3%) bacteria had O157 and H7 genes, respectively. Evaluation of virulence genes showed that genes eaeA (15.4%), stx1 and eaeA (15.4%), stx2 (7.7%), and stx2 and eaeA (7.7%) had the highest frequency in E. coli O157:H7.
Conclusion: Due to the severity of pathogenicity, low infectious dose of E. coli O157: H7, and its pathogenic genes, more extensive studies and genotyping of E. coli O157: H7 are required to be conducted in other areas of Iran in order to measure the frequency in UTIs and control the infections caused by E. coli O157: H7.
Keywords: Escherichia coli O157:H7; Urinary Tract Infections; Shiga Toxin 1; Shiga Toxin 2.
Zahra Khozein , Ayatollah Nasrolahi Omran , Aylar Jamali ,
Volume 9, Issue 5 (11-2015)
Abstract
Abstract
Background and Objective: the Formation of urinary infection by uropathogenic E.coli needs numerous virulence factors and biofilm formation is among these factors. Bacteria that form biofilms express phenotype traits that appear according to the bacteria type. Cellulose is an important compound on the outside of E.coli causing bacterial cell-cell reactions and connection to nonliving surfaces. Curli pili cause the reaction between cell-cell and surface-cell in biofilms and lead to bacteria aggregation. Microorganisms’ ability to form biofilm on a surface depends on the surface nature and its conditions. This study aimed at determining the production ability of cellulose polysaccharide and curli pili in UPEC strains, and its correlation with formation and intensity of biofilm.
Methods: In this study carried out to compare the ability of cellulose and pili curli production ability in 40 uropathogenic E.coli isolates ,by morphotype method in Congo Red medium (CR), each isolate was incubated at 37 oC, for 24 hours. After 24 hours, all colonies’ morphology characteristics were studied
Results: It was shown that 67.5% of strains produced cellulose and 72.5% produced curli pili. In addition, 92.6% and 89% of isolates that produce cellulose and curli, respectively, had a moderate to strong biofilm. Moreover, it was shown that there is a significant correlation between cellulose and / or curli pili production with biofilm intensity.
Conclusion: About 70% of E.coli isolates from patients' urine are able to produce cellulose or curli pili; therefore, it can be concluded that the production of these two combinations is effective in amount and intensity of biofilm formation.
Keywords: Escherichia coli; Cellulose Polysaccharide; Curli Pili; Biofilm.
Hesam Alizade , Fatemeh Fallah , Reza Ghanbarpour , Hosein Goudarzi , Hamid Sharifi , Mohammad Reza Aflatoonian ,
Volume 10, Issue 2 (3-2016)
Abstract
ABSTRACT
Background and Objective: One of the main tasks of clinical microbiology laboratories is to determine antibiotic resistance profiles in common pathogens and ensure the selection of effective antibiotics for certain infections. The aim of this study was to compare the methods of disk diffusion, broth microdilution and modified Hodge test in Escherichia coli isolates from urinary tract infection and diarrhea for susceptibility testing against beta-lactam antibiotics in Kerman, Iran.
Methods: In this study, 432 E. coli isolates were collected from diarrhea (216 isolates) and urinary tract infection samples (216 isolates). The antibiotic susceptibility testing methods of disk diffusion, broth microdilution and modified Hodge test were performed according to the Clinical and Laboratory Standards Institute guidelines.
Results: The findings of disk diffusion method showed that resistance to cefotaxime, ceftazidime, aztreonam, cefepime and imipenem was 51.15%, 30.55%, 24.30%, 15.27% and 1.85%, respectively. In the disk diffusion test, 51.15% of the isolates were resistant to at least one antibiotic, all of which were later evaluated by the broth microdilution method. Moreover, 52.94%, 17.19%, 13.12% and 0.90% of the isolates were resistant to cefotaxime, ceftazidime, cefepime and imipenem, respectively. All of the isolates were evaluated for the production of carbapenemase enzyme by the modified Hodge test and none of the isolates were found as positive.
Conclusion: This study shows that performing carbapenem tests is very challenging, and laboratories are recommended to use secondary and independent antibiotic susceptibility tests such as modified Hodge test to confirm the carbapenem-resistant results.
Mohammad Faezi Ghasemi , Seyede Negin Dibadji,
Volume 10, Issue 5 (9-2016)
Abstract
ABSTRACT
Background and Objective: Extended-spectrum beta-lactamases (ESBL) are widely produced by Escherichia coli strains. The aim of this study was to determine frequency of blaOXA-1 and blaSHV genes in E.coli strains isolated from patients hospitalized in city of Rasht, Iran.
Methods: In this cross-sectional study, 200 samples were collected from patients. The E. coli strains were identified using morphological characteristics and biochemical tests. Antimicrobial susceptibility testing was performed. The prevalence of the blaOXA-1 and blaSHV genes in the E. coli isolated was assessed by PCR method.
Results: Overall, 160 E. coli strains were isolated. Of these, 83 (51.9%) showed ESBL activity while 71 (48.1%) did not. All positive strains were resistant to cephalothin. Moreover, 98.8% of ESBL-producing strains were resistance to amoxicillin, cefotaxime and ceftriaxone. The prevalence of the blaOXA-1 and blaSHV genes in ESBL-producing strains were 45% and 17%, respectively. In addition, 28.9% of the strains had both genes while the genes were absent in 9.6% of the strains.
Conclusion: Prevalence of the blaOXA-1gene is higher than that of the blaSHV gene. The absence of both genes in some isolates indicates the possible role of other genes in the ESBL activity.
Keywords: Prevalence, ESBLs, Escherichia coli, blaOXA-1gene, blaSHV gene.
Mohammad Arjmand , Ezatallah Ghaemi , Ailar Jamalli ,
Volume 11, Issue 1 (1-2017)
Abstract
ABSTRACT
Background and Objectives: Biofilm is a population of bacteria growing on a surface and enclosed in an exopolysaccharides matrix, which increases resistance to antimicrobial agents and immune response. Uropathogenic Escherichia coli (UPEC) are biofilm-forming bacteria and the most common cause of urinary tract infections (UTIs). This study evaluated the effect of different concentrations of glucose, NaCl, blood, serum and urine on biofilm formation and antigen 43 (Ag43) gene expression, as a main gene involved in biofilm formation.
Methods: Among E. coli isolates from patients with UTI, four extended-spectrum beta-lactamase (ESBL) and non-ESBL strains, and a standard UPEC strain were selected. Biofilm formation of the strains in brain heart infusion (BHI) broth with different concentrations of glucose, NaCl, sheep blood, serum and human urine was evaluated using microplate method and crystal violet staining. Ag43 gene expression was investigated using Real-Time polymerase chain reaction, SYBR Green dye, and specific primers.
Results: Presence of glucose at all concentrations reduced biofilm formation. Presence of 1% NaCl, 1% sheep blood, 10% bovine serum, and 5% urine significantly increased biofilm formation. Expression of Ag43 by the strains grown under 1% glucose, 1% NaCl, 1% sheep blood, 10% bovine serum and 5% urine decreased.
Conclusion: All environmental factors other than glucose may increase biofilm formation of E. coli at different concentrations. This is not affected by factors such as isolation from inpatient or outpatients and type of strains (ESBL or non-ESBL). Contrary to our expectations, Ag43 expression is independent of environmental factors and decreases even under the most suitable concentrations.
Keywords: Biofilms, Uropathogenic Escherichia coli, UTI, Antigen 43, Real-Time PCR.
Majid Komijani , Majid Bouzari , Fateh Rahimi ,
Volume 11, Issue 2 (3-2017)
Abstract
ABSTRACT
Background and Objective: Escherichia coli is one of the most common causes of hospital-acquired infections. Extended-spectrum β-lactamase (ESBL)-producing E. coli strains are resistant to third-generation cephalosporins. The three main genes involved in ESBL production are TEM, SHV and CTX-M. Detection of ESBL-producing E. coli is of importance for infection control, reduction of excessive antibiotic use and epidemiological surveillance. This study aimed to detect ESBL-producing E. coli strains isolated from wound infections using phenotypic and molecular methods.
Methods: During 2013- early 2015, 86 strains were collected from three hospitals in Isfahan, Iran. Antibiotic susceptibility testing was done using ceftazidime and ceftazidime + clavulanic acid discs. Polymerase chain reaction was used for the detection of the three resistance genes.
Results: The resistance genes SHV, CTX-M and TEM were detected in 49 isolates (56.9%). In addition, 39 isolates (45%) were ESBL-producing strains. According to the results, 5 (5.8%), 14 (16.2%), 19 (22%) and 11 (12.7%) isolates contained the SHV, CTX-M, TEM and CTX-M + TEM genes, respectively. The frequency of CTX and TEM were significantly higher than that of SHV gene (P <0.05). Most of the isolated bacteria were resistant to cefazolin and sensitive to nitrofurantoin.
Conclusions: There is a difference between the frequency of ESBL-positive isolates reported in the phenotypic and genotypic methods, which could be due to the lower sensitivity of the phenotypic method and impact of environmental factors on the emergence of antibiotic resistance.
Keywords: Antibiotic resistance genes, ESBL, TEM, SHV, CTX-M, Escherichia coli.
Shahram Shahraki Zahedani , Nasrin Sayadzai,
Volume 12, Issue 2 (3-2018)
Abstract
ABSTRACT
Background and Objectives: Diarrheagenic Escherichia coli (DEC) pathotypes are important causes of diarrhea among children in developing countries. The objective of this study was to determine the frequency and antibiotic resistance pattern of DEC pathotypes in children aged less than 10 years.
Methods: This cross-sectional study was done on 300 E. coli strains isolated from diarrheic stool samples of children aged less than 10 years who were admitted to hospitals and central laboratory in Zahedan, between July and October 2016. DEC pathotypes were identified by standard biochemical testing and phenotypic testing using polyvalent antiserums. Antibiotic resistant pattern of these strains was evaluated against 11 different antibiotics by the agar disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines.
Results: Of the 300 E. coli isolates, 89 (29.6%) were found positive for DEC using polyvalent antiserums. In this study, 35 cases (39.3%) reacted with antiserum 1, 21 cases (25.8%) reacted with the antiserum 2, and 31 cases (34.8%) reacted with antiserum 3. The highest rate of resistance was observed against ampicillin (94.8%), tetracycline (87.2%), and co-trimoxazole (70.5%). In addition, the lowest rate of resistance was related to imipenem (1%) and ciprofloxacin (8.9%).
Conclusion: DEC pathotypes are the important causes of diarrhea among children admitted to hospitals of Zahedan. Considering the high rate of antibiotic resistance among these pathotypes in this region, prescription of antibiotics should be based on accurate detection of these strains.
Keywords: Escherichia coli, Child, Antibiotic Resistance.
Mahsa Yazdi, Majid Bouzari, Ezzat Allah Ghaemi,
Volume 12, Issue 5 (9-2018)
Abstract
ABSTRACT
Background and objectives: Urinary tract infections (UTIs) are one of the most common infectious diseases caused by bacteria. The primary etiologic agent of UTIs is Escherichia coli. Uropathogenic E.coli (UPEC) strains have a number of specific virulence factors, which can worsen UTIs. This study was performed to detect fim, pap, sfa and afa genes among E.coli strains isolated from UTIs.
Methods: A total of 100 E. coli isolates from patients with UTI was collected between June and December 2015 from Mosavi and Sayyad Shirazi hospitals in Gorgan, Iran. All bacterial isolates were identified via standard biochemical testing and Gram straining. Presence of the genes was assessed by polymerase chain reaction.
Results: The frequency of the fim, pap, sfa and afa genes was 100%, 79%, 69% and 8%, respectively. All isolates contained at least one virulence gene. Prevalence of multiple adhesion genes was 6% for all genes and 65% for three genes (fim, pap and sfa) together. In addition, the frequency of the fim gene was significantly higher than that of the other genes (P<0.0001).
Conclusion: The results of this study indicate the high prevalence of virulence factors that can enhance pathogenicity of E. coli. Therefore, these factors could be used as diagnostic markers or vaccine targets.
Keywords: Virulence factors, Urinary tract infection, Uropathogenic Escherichia coli.
Mohammad Habibi Juybari , Hamidreza Pordeli , Saeid Mikaeili ,
Volume 13, Issue 3 (5-2019)
Abstract
ABSTRACT
Background and Objectives: Schiff base ligands are prepared via the condensation reaction of 1, 10- dimethyl–phenantroline aldehyde derivative with some nitrogen donor ligands, such as benzene ring that have different functional groups (-OH, -SH, -OCH3,-CH2OH, -Br) in acetonitrile. Recent studies suggest that Schiff bases might have antibacterial activity. Therefore, we aimed to synthesize new Schiff base complexes and evaluate their antibacterial activity against a number of Gram-positive and Gram-negative bacteria.
Methods: Schiff base ligands and their complexes were characterized by mass spectrometry, infrared spectroscopy and nuclear magnetic resonance spectroscopy. The in vitro antibacterial activity of the Schiff base ligands and metal ions against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was evaluated by determining minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the broth dilution method.
Results: All synthesized Schiff bases exhibited favorable antibacterial activity against the tested microorganism, but the antibacterial effect of compounds 3OH and 3SH was more significant than that of other compounds.
Conclusion: Compound 3EOH has favorable antibacterial activity against the tested bacteria.
Keywords: Schiff bases, antibacterial effect, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa.
Hamidreza Ebrahimnezhad, Leila Barzegar, Davoud Esmaeili,
Volume 14, Issue 1 (1-2020)
Abstract
ABSTRACT
Background and Objectives: Probiotics are live microorganisms that function through various mechanisms and affect the alteration of the commensal microbiota against pathogens. Nowadays, given the problems associated with antibiotics use, probiotic strains offer a novel and appropriate alternative for the treatment of diseases such as diarrhea. The aim of this study was to investigate the antibacterial synergism of Lactobacillus spp., Bifidobacterium spp. and Escherichia coli strain Nissle 1917 (ECN) on the clinical sample of diarrheagenic E.coli and Campylobacter jejuni.
Methods: A paper disk-diffusion technique was used to evaluate the antibacterial activity. Sterile 6 mm paper disks were saturated with probiotic suspensions made by settling probiotic medications into distilled water. Three kinds of disk were prepared. One disk was prepared for Lactobacillus spp. and Bifidobacterium spp., another for ECN, and the third was made by combined probiotics. Clinical samples of diarrheagenic E.coli and Campylobacter jejuni were cultivated on Muller Hinton agars, and disks were placed on the inoculated Muller Hinton agars. All plates were incubated under microaerophilic and appropriate conditions.
Results: The zone of inhibition (ZOI) of the bacterial growth was measured. All pathogenic microorganisms showed sensitivity to the probiotic disks. The combined disks had better effects against pathogens compared with single disks.
Conclusion: A considerable synergistic effect was observed in the results of combined probiotics; therefore, combined strains can be more efficient against intestinal pathogens in comparison with single probiotics.
Keywords: Probiotic, Lactobacillus, Bifidobacterium, Escherichia coli Nissle, Diarrhea, Campylobacter jejun.i.
Ezzat Allah Ghaemi, Fahimeh Azadi, Naeme Javid, Hanieh Bagheri,
Volume 14, Issue 4 (7-2020)
Abstract
Background and objectives: Drug resistance in Staphylococcus aureus and Escherichia coli, as severe pathogenic bacteria, has become a health challenge. However, nanoparticles have been introduced as effective candidates for their eradication. In this study, we investigated presence of genes involved in conferring resistance to silver nanoparticles in S. aureus and E. coli isolates and evaluated its association with minimal inhibitory concentration (MIC) of the nanoparticles against these isolates.
Methods: The MIC of silver nanoparticles against 121 clinical isolates of E. coli and 183 S. aureus isolates was assessed by broth microdilution assay. Presence and expression of the silver resistance genes (silE, silR/S) in the isolates were investigated by PCR and real-time PCR, respectively.
Results: The silE gene was found in three (1.6%) S. aureus and four (3%) E. coli isolates. MIC of silver nanoparticles against S. aureus isolates with the silE gene was 1, 2 and 8 µg/ml. Moreover, the MIC of the nanoparticles against silE-positive E. coli isolates was 16 μg/ml in three cases and 8 μg/ml in one case. None of the S. aureus isolates contained the silR/S gene, but presence of both silE and silR/S was confirmed in two E. coli isolates. Real-time PCR showed no sil expression in the isolates containing the resistance genes.
Conclusion: The frequency of the silver resistance genes among S. aureus and E. coli isolates is very low. There is no relationship between presence of the resistance genes and the MIC value of silver nanoparticles.
