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Papers by niloufar rashidi

Journal of Medical Sciences, 2008

Avicenna Journal of Clinical Microbiology and Infection

Background: Helicobacter pylori (H. pylori) is identified as the most frequent agent of bacterial... more Background: Helicobacter pylori (H. pylori) is identified as the most frequent agent of bacterial infections in humans which can cause various gastrointestinal diseases. This pathogen has infected approximately half of the world’s population, and its outbreak has varied across different regions. The purpose of this study was to estimate the H. pylori infection prevalence amongst patients in Fardis county, Alborz province, Iran, using noninvasive methods. Methods: A total of 5677 patients were analyzed from September 2020 to October 2021 to detect H. pylori by the use of enzyme-linked immunosorbent assay (ELISA) IgG, IgA, and IgM tests, stool antigen test (SAT), and urea breath test (UBT). Results: Of 5677 patients, 3486 (61.4%) were female and 2191 (38.6%) were male with the mean age of 38.82 ± 18.289 years old. The overall rate of H. pylori infection positive was 31.46%, and the serological tests were the most prescribed types of tests. The IgG test and then SAT detected the most p...

Background: This study was conducted to compare the efficacy of enzyme-linked immunosorbent assay... more Background: This study was conducted to compare the efficacy of enzyme-linked immunosorbent assay (ELISA) for detecting anti-Helicobacter pylori (H. pylori) specific IgG antibodies in specimens of oral fluid and serum with bacteriological tests. Methods: Antral biopsy specimens, as well as serum and oral fluid samples were collected from 97 patients who underwent upper gastrointestinal endoscopy. The presence or absence of current H. pylori infection was determined by culture, histology and urease detection. Anti-H. pylori specific IgG was detected in serum and oral fluid, using an established lab-made, and a commercial ELISA kit. The obtained data were compared with results of bacteriological tests. Results: In all, 62 (64%) of 97 patients were positive for H. pylori by one or more of the gold standard tests (culture, histology and urease detection). Lab-made enzyme-linked immunoassay of oral fluid had a sensitivity and specificity of 92% and 83% respectively. A sensitivity and specificity of 87% and 83%, respectively, was obtained with the commercial kit. Lab-made enzyme-linked immunoassay of serum samples had a sensitivity and specificity of 90% and 88%, respectively. A sensitivity of 86% and specificity of 86% was obtained with the commercial kit. Conclusion: Detection of anti-H. pylori specific IgG in oral fluid by ELISA is comparable in sensitivity and specificity with serum based methods. Oral fluid based ELISA could provide a reliable, non-invasive method for the diagnosis of H. pylori infection. Saliva testing may have a role in epidemiological studies.

International Work-Conference on Bioinformatics and Biomedical Engineering, 2013

Journal of Fasa University of Medical Sciences, 2019

Background & Objective: Pseudomonas aeruginosa is known as a major cause of hospital-acquired inf... more Background & Objective: Pseudomonas aeruginosa is known as a major cause of hospital-acquired infections due to its high antibiotic resistance. Biofilm formation is an important virulence factor in P. aeruginosa infections. This pathogen produces extracellular hydrolases such as esterase estA during biofilm formation which can influence the formation and construction of biofilm. The purpose of this study was to detect the antibiotic resistance and distribution of estA gene among biofilm-producing P. aeruginosa strains isolated from burn patients. Materials & Methods: A total of 37 strains of P. aeruginosa were isolated from burn patients in Taleghani hospital in Ahvaz and identified using standard bacteriological procedures. Antibiotic susceptibility test was performed by disk diffusion method according to the CLSI 2015. Biofilm formation was measured by micro titer plate. Existence of estA gene was detected by PCR. Results: The estA gene existed in 97.3% of isolates and 78.3% of P....

Scientific Reports

Nowadays, increasing extended-spectrum β-lactamase (ESBL)-producing bacteria have become a global... more Nowadays, increasing extended-spectrum β-lactamase (ESBL)-producing bacteria have become a global concern because of inducing resistance toward most of the antimicrobial classes and making the treatment difficult. In order to achieve an appropriate treatment option, identification of the prevalent species which generate ESBL as well as their antibiotic susceptibility pattern is essential worldwide. Hence, this study aimed to investigate the prevalence of ESBL-producing bacteria and assess their drug susceptibility in Fardis Town, Iran. A total of 21,604 urine samples collected from patients suspected to have urinary tract infection (UTI) were processed in the current study. The antimicrobial susceptibility of the isolates was tested by the disk diffusion method. The ESBL producing bacteria were determined by Double Disc Synergy Test (DDST) procedure. Bacterial growth was detected in 1408 (6.52%) cases. The most common bacterial strains causing UTI were found E. coli (72.16%), follow...

Molecular Genetics, Microbiology and Virology

Clinical Laboratory

Background: Pseudomonas aeruginosa is a major cause of hospital-acquired infection due to its hig... more Background: Pseudomonas aeruginosa is a major cause of hospital-acquired infection due to its high antibiotic resistance and biofilm formation ability. P. aeruginosa produces elastase lasB during biofilm formation, which can influence properties of biofilm. This study was carried out to evaluate the antibiotic resistance and distribution of the lasB gene among biofilm-producing P. aeruginosa strains isolated from burn patients. Methods: A total of 128 clinical samples were collected from burn patients. The P. aeruginosa isolates were identified using standard bacteriological procedures. Antibiotic susceptibility test was performed by the disk diffusion method. Biofilm formation was measured by microtiter plate assay. The presence of lasB gene was detected by PCR. Results: A total of 75 samples were positive for P. aeruginosa. A high rate of resistance was seen against ceftriaxone, cefotaxime, and piperacillin/tazobactam. Biofilm formation was seen in 57.3% of the isolates and the prevalence of the lasB gene was 85.3%. Biofilm formation in isolates without lasB was lower and these isolates were more sensitive to imipenem and piperacillin/tazobactam. Conclusions: In the present study, we did not find a statistically significant relationship among elastase gene (lasB) presence, antibiotic resistance, and biofilm formation in P. aeruginosa strains isolated from burn patients.

Critical Reviews in Microbiology

Helicobacter pylori has grown to colonize inside the stomach of nearly half of the world'... more Helicobacter pylori has grown to colonize inside the stomach of nearly half of the world's population, turning into the most prevalent infections in the universe. Medical care failures noticeably confirm the need for a vaccine to hinder or deal with H. pylori. This review is planned to discuss the most known factors as a vaccine candidate, including single (AhpC, BG, CagA, KatA, Fla, Hsp, HWC, Lpp, LPS, NAP, OMP, OMV, SOD, Tpx, Urease, VacA) and multi-component vaccines. Many promising results in the field of single and multivalent vaccine can be seen, but there is no satisfactory outcome and neither a prophylactic nor a therapeutic vaccine to treat or eradicate the infection in human has been acquired. Hence, selecting suitable antigen is an important factor as an appropriate adjuvant. Taken all together, the development of efficient anti-H. pylori vaccines relies on the fully understanding of the interactions between H. pylori and its host immune system. Therefore, more work should be done on epitope mapping, analysis of molecular structure, and determination of the antigen determinant region as well due to design a vaccine, preferably a multi-component vaccine to elicit specific CD4 T-cell responses that are required for H. pylori vaccine efficacy.

African Journal of Biotechnology, 2011

Jundishapur Journal of Microbiology, 2015

Background: Helicobacter pylori infection is highly prevalent in the developing countries. It cau... more Background: Helicobacter pylori infection is highly prevalent in the developing countries. It causes gastritis, peptic ulcer disease, and gastrocarcinoma. Treatment with drugs and antibiotics is problematic due to the following reasons: cost, resistance to antibiotics, prolonged treatment and using multiple drugs. Catalase is highly conserved among the Helicobacter species and is important to the survival of the organism. It is expressed in high amounts and is exposed to the surface of this bacterium; therefore it represents a suitable candidate vaccine antigen. Objectives: A suitable approach in H. pylori vaccinology is the administration of epitope based vaccines. Therefore the responses of T-cells (IFN-γ and IL-4 production) against the catalase of H. pylori were determined. Then the quality of the immune responses against intact catalase and three epitopes of catalase were compared. Materials and Methods: In this study, a composition of three epitopes of the H. pylori catalase was selected based on Propred software. The effect of catalase epitopes on T-cells were assayed and immune responses identified. Results: The results of IFN-γ, IL-4 production against antigens, epitopes, and recombinant catalase by T-cells were compared for better understanding of epitope efficiency. Conclusions: The current research demonstrated that epitope sequence stimulates cellular immune responses effectively. In addition, increased safety and potency as well as a reduction in time and cost were advantages of this method. Authors are going to use this sequence as a suitable vaccine candidate for further research on animal models and humans in future.

African Journal of …, 2011

Bioinformatics tools are helpful for epitopes prediction directly from the genomes of pathogens i... more Bioinformatics tools are helpful for epitopes prediction directly from the genomes of pathogens in order to design a vaccine. Epitopes are sub-sequences of proteins (8 to 10 mer peptides) which bind to MHC to interact with the T cell receptors and stimulate immune responses. Finding a suitable vaccine against Helicobacter pylori is necessary, because of high prevalence of the infection (25 to 90%). Moreover, this bacteria has been classified as a grade I carcinogen by WHO since 1994. Catalase, an important enzyme in the virulence of H. pylori, could be a suitable candidate for vaccine design because it is highly conserved, which is important for the survival of H. pylori; it is expressed in high level and it is exposed on the surface of the bacteria. In this study, we designed epitope-based vaccine for catalase specific regions of H. pylori by means of immunobioinformatic tools. H. pylori (26695) catalase has been compared with human catalase in order to select specific regions. Afterwards, epitopes of catalase were determined by propred software. Among predicted epitopes, three epitopes were selected including, MVNKDVKQTT, VLLQSTWFL and FHPFDVTKI. Three candidates out of 51catalase antigen epitopes had the highest score for reactivating with MHC II MHC in propred software. The candidate epitopes for vaccine design should be rather a composition of considering epitopes: MVNKDVKQTTKKVLLQSTWFLKKFHPFDVTKI. In this manner, 39 of 51 alleles of MHC class ІІ were involved and stimulated T-cell responses. We believe prediction of catalase epitopes by the immunoinformatics tools would be valuable for developing new immuoprophylatic strategy against H. pylori infection.