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Papers by maryam mirshekar

Archives of Microbiology, Jul 4, 2022

The expression of type II TA system genes following exposure to the subinhibitory concentration o... more The expression of type II TA system genes following exposure to the subinhibitory concentration of gentamicin and acid stress in Brucella spp. Fatemeh amraei a,b , Negar narimisa a,b , Behrooz sadeghi kalani c,d , Rokhsareh mohammadzadeh a,b , Vahid lohrasbi a,b , Faramarz masjedian jazi a,b, *

PubMed, 2020

Background: Nosocomial infection caused by Acinetobacter baumannii has emerged as a world-wide se... more Background: Nosocomial infection caused by Acinetobacter baumannii has emerged as a world-wide serious problem in the emergence of multidrug-resistant (MDR). Infections caused by antibiotic-resistant strains of A. baumannii cannot be completely eliminated among the infected patients. This study aimed to monitor antibiotic resistance among A. baumannii strains isolated from burnt children. Methods: After performing biochemical identification tests on 115 isolates, 62 were detected as A. baumannii . Minimum inhibitory concentration (MIC) was used to test susceptibility to colistin, and disk agar diffusion was used for the susceptibility of the isolates to the antibiotics Ciprofloxacin, Amikacin, Gentamicin, Cefepime, Meropenem, Imipenem, Ceftazidime, Levofloxacin and Piperacillin/Tazobactam. Bacterial species were isolated and identified as multidrug-resistant (MDR), extensively drug-resistant (XDR) and pan drug-resistant (PDR), based on the susceptibility patterns to elected antibiotics, deputing different classes of antimicrobial. Results: The antibiotic susceptibility pattern out of a total of 62 bacterial strains used in this study. Thirty-six (58%) strains were categorized as MDR, 17 (27.5%) as XDR, and nine (14.5%) as PDR. Conclusion: To reduce the threat of antimicrobial resistance, MDR, XDR and PDR A. baumannii strains must be evaluated by all clinical microbiology laboratories.

Journal of Basic Microbiology, Sep 9, 2022

Aims: Urinary tract infection (UTI) is one of the most common infections worldwide. The aim of th... more Aims: Urinary tract infection (UTI) is one of the most common infections worldwide. The aim of this study was to investigate the association between the ESBLs genes and quinolone resistance in uropathogenic Escherichia coli strains isolated from patients with urinary tract infection. Materials & Methods: A total of 150 E. coli isolates were collected from patients with urinary tract infection, referring to Firouzgar hospital in Tehran, Iran. Antimicrobial susceptibility of isolates was determined by disk diffusion method. Double-disk diffusion test was performed for phenotypic identification of extended-spectrum β-lactamase (ESBL)-producing isolates. PCR was used for the detection of ESBL-encoding and quinolone (qnr) resistance genes. Findings: There was a high resistance rate to most of the studied antimicrobial agents. Phenotypically, 75% of the isolates produced an ESBL enzyme and were resistant to different antimicrobial classes. Overall, 83% of the isolates carried ESBL genes, especially bla TEM and bla CTX-M. Also, 75% of the isolates were positive for the presence of quinolone resistance genes, including qnrA, qnrB, qnrS, and qepA. The present study results indicated the association between the presence of various ESBLs genes and quinolone resistance in uropathogenic E. coli strains. Conclusion: Resistance patterns showed an increase in the incidence of antibacterial resistance in E. coli strains. The current study results indicated the high prevalence rate of ESBL-producing isolates and quinolone resistance genes. Simultaneous presence of genes responsible for antibacterial resistance has made the treatment of UTI more challenging than before.

Medical journal of the Islamic Republic of Iran, Oct 30, 2020

Background: Nosocomial infection caused by Acinetobacter baumannii has emerged as a worldwide ser... more Background: Nosocomial infection caused by Acinetobacter baumannii has emerged as a worldwide serious problem in the emergence of multidrug-resistant (MDR). Infections caused by antibiotic-resistant strains of A. baumannii cannot be completely eliminated among the infected patients. This study aimed to monitor antibiotic resistance among A. baumannii strains isolated from burnt children. Methods: After performing biochemical identification tests on 115 isolates, 62 were detected as A. baumannii. Minimum inhibitory concentration (MIC) was used to test susceptibility to colistin, and disk agar diffusion was used for the susceptibility of the isolates to the antibiotics Ciprofloxacin, Amikacin, Gentamicin, Cefepime, Meropenem, Imipenem, Ceftazidime, Levofloxacin and Piperacillin/Tazobactam. Bacterial species were isolated and identified as multidrug-resistant (MDR), extensively drug-resistant (XDR) and pan drug-resistant (PDR), based on the susceptibility patterns to elected antibiotics, deputing different classes of antimicrobial. Results: The antibiotic susceptibility pattern out of a total of 62 bacterial strains used in this study. Thirty-six (58%) strains were categorized as MDR, 17 (27.5%) as XDR, and nine (14.5%) as PDR. Conclusion: To reduce the threat of antimicrobial resistance, MDR, XDR and PDR A. baumannii strains must be evaluated by all clinical microbiology laboratories.

Research Square (Research Square), Jan 7, 2021

Objectives: Failure of infection therapy in the presence of antibiotics has become a major proble... more Objectives: Failure of infection therapy in the presence of antibiotics has become a major problem which has been mostly attributed to the ability of bacterial persister cell formation. Bacteria use various mechanisms to form persister cells in different phases, among which is the toxin-antitoxin (TA) systems. This study aimed at investigating the expression of type II TA system genes under the stress of ciprofloxacin and colistin antibiotics in the exponential and stationary phases. Methods: To determine the effects of ciprofloxacin and colistin on persister cell formation in the exponential and stationary phases of Pseudomonas aeruginosa strains, colony counting was performed at different time intervals in the presence of 5-fold MIC of ciprofloxacin and colistin. In addition, the expression of relBE, Xre-COG5654, vapBC, and Xre-GNAT genes in P. aeruginosa isolates was assessed 3.5 h after antibiotic treatment in the exponential and stationary phases using qRT-PCR. Results: Our results indicated the presence of persister phenotype of P. aeruginosa strains in the presence of 5-fold MIC of ciprofloxacin and colistin compared to the control after 3.5 h of incubation in the exponential and stationary phases. Also, the number of persister cells in the stationary phase was higher than that of the exponential phase. According to the results of qRT-PCR, ciprofloxacin and colistin may induce persister cells by increasing the expression of type II TA systems in stationary and exponential phases. Conclusion: Ciprofloxacin and colistin may increase the formation of persister cells by affecting the expression of type II TA systems.

Journal of Basic Microbiology, Jan 19, 2023

The emergence of multidrug‐resistant (MDR) strains of Klebsiella pneumoniae is associated with hi... more The emergence of multidrug‐resistant (MDR) strains of Klebsiella pneumoniae is associated with high morbidity and mortality due to limited treatment options. This study attempts to biologically synthesize silver nanoparticles (AgNPs) and investigate their effect on expression levels of virulence and biofilm‐related genes in clinically isolated K. pneumoniae. In this study, biofilm formation ability, antibiotic resistance pattern, extended‐spectrum β‐lactamases (ESBLs), and carbapenemases production were investigated for 200 clinical isolates of K. pneumoniae using phenotypic methods. Polymerase chain reaction (PCR) was used to detect virulence and biofilm‐related genes, ESBL‐encoding genes, and carbapenem resistance genes. AgNPs were synthesized using the bio‐reduction method. The antibacterial effects of AgNPs were investigated by microdilution broth. In addition, the cytotoxic effect of AgNPs on L929 fibroblast cell lines was determined. The effects of AgNPs on K. pneumoniae virulence and biofilm‐related genes (fimH, rmpA, and mrkA) were determined using quantitative real‐time PCR. Thirty percent of the isolates produced a strong biofilm. The highest and lowest levels of resistance were observed against amoxicillin/clavulanic acid (95.4%) and tigecycline (96%), respectively. About 31% of isolates were considered positive for carbapenemases, and 75% of the isolates produced an ESBLs enzyme. Different frequencies of mentioned genes were observed. The synthesized AgNPs had a spherical morphology and varied in size. AgNPs inhibited the growth of MDR K. pneumoniae at 128 µg/ml. In addition, AgNPs downregulated the expression of fimH, rmpA, and mrkA genes by 10, 7, and 14‐fold, respectively (p < 0.05), also exerted no cytotoxic effect on L929 fibroblast cell lines. It was revealed that AgNPs lead to a decrease in expression levels of virulence and biofilm‐related genes; therefore, it was concluded that AgNPs had an excellent antibacterial effect on MDR K. pneumoniae.

American Journal of Reproductive Immunology, May 2, 2022

Gene Reports, Dec 1, 2020

Abstract Background The emergence of multiple drug resistance (MDR) Klebsiella pneumoniae (KP) is... more Abstract Background The emergence of multiple drug resistance (MDR) Klebsiella pneumoniae (KP) is a public health concern. Colistin is used as a last-resort treatment option for MDR-KP. The emergence of colistin-resistant isolates is a major public health challenge. The aim of this study was to explore genes and the responsible mechanisms of colistin resistance in MDR-KP isolates in Tehran, Iran. Methods 94 KP isolates suspected to be colistin-resistant (by disc diffusion) from urine, sputum, blood collected between 2018 and 2019 were studied. Isolates were tested for antibiotic resistance determinants and their colistin minimum inhibitory concentration (MIC). The presence of β-lactamase and quinolone genes, plasmid-encoded resistance genes, mcr-1 and mcr-2 genes, and nucleotide sequences of mgrB were determined by polymerase chain reaction (PCR). Results 20 of 94 isolates were colistin resistance KP (Col-R KP) (21%) with MIC ranged from 4 to 128 μg/ml. Coproduction of β-lactamases, and quinolones was in 18 (90%) Col R KP isolates. Four (20%) isolates had mutations in mgrB. mgrB was inactivated by nonsense mutations at codons 21 and insertion of IS 903B elements (IS5); and elongation of mgrB. 16 (80%) ColR KP isolates harbored wild type of mgrB. There is not any mcr-1, mcr-2 encoding genes on plasmids among all the isolates. Conclusion We detected a high frequency of both qnr and ESBL resistance genes among colistin-resistant K. pneumoniae. Also, colistin resistance mainly occur with lipopolysaccharide (LPS) modification by different mechanisms. Spread of resistance against colistin resulting in treatment failure the colistin-included therapy regimen which is used as a last line of defense against infection due to MDR Gram-negative pathogens. The control of usage of colistin in hospital is necessary to prevent the spread of resistance among isolates.

Journal of Applied Sciences and Nanotechnology, 2021

In this study 50 isolates were obtained from the Baghdad teaching city medicine laboratories, fro... more In this study 50 isolates were obtained from the Baghdad teaching city medicine laboratories, from wounds and burns. Isolates were identified exercise VITEK 2 system (Biomerieux). Streptococcus pyogenes isolate was used to create the biosynthesize of silver nanoparticles'' against some pathogenic microbes such as Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans. Evaluation of the effect of the created biosynthesis silver nanoparticles'' (AgNPs) by Streptococcus pyogenes on the biofilm formation by various human pathogenic bacteria. Biosynthesis of AgNPs was characterized by ultraviolet-visible absorption spectroscopy, the observation of color change of the experimental samples in the presence of 1 mM AgNO3 at 410 nm. A color change from pale yellow to slightly brown occurred for bacterial supernatant within 24 hours of incubation in the presence of light Scanning electron microscope (SEM), the biosynthesis silver nanoparticles'' are predominately circular fit as a fiddle having a smooth surface and very much scattered with close minimal game plan, X-ray diffraction (XRD). The. The normal molecule size was determined by Debye-Scherer equation and its evaluation was roughly 6.43nm. The normal molecule size was determined by Debye-Scherer equation and its evaluation was roughly 6.43nm. The importance of this work lies in the possibility of synthesizing the silver nanoparticles'' using these bacteria, which are considered as types of fastidious bacteria. As far as the researcher's knowledge is concerned, this is study is the first of its kind in Iraq.

Journal of Basic Microbiology

Copyright© 2018, TMU Press. This open-access article is published under the terms of the Creative... more Copyright© 2018, TMU Press. This open-access article is published under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License which permits Share (copy and redistribute the material in any medium or format) and Adapt (remix, transform, and build upon the material) under the Attribution-NonCommercial terms. Evaluation of the Effects of Curcumin Nanoparticles on the Expression of Genes Involved in Biofilm Formation in UPEC

American Journal of Reproductive Immunology

Iranian Journal of Medical Microbiology

Background and Aim: The healthy people's fecal flora in the community represents a large potentia... more Background and Aim: The healthy people's fecal flora in the community represents a large potential reservoir. Therefore, the current study aimed to detect antibiotic resistance patterns and virulence factors in Klebsiella pneumoniae isolated from healthy volunteers' feces. Materials and Methods: Three hundred and fifty stool specimens were collected from sales rep healthy individuals referring to the Northwest Tehran Health Centers to get a health card. Bacterial isolation, identification, and antimicrobial susceptibility testing were conducted according to the routine instructions. In addition, polymerase chain reaction (PCR) was used to detect the genetic factors responsible for producing extended-spectrum β-lactamases (ESBLs: SHV, TEM, and CTX-M) blaKPC and other virulence genes. Results: Among fecal samples analyzed, 60 (17.1%) K. pneumoniae were isolated. The results demonstrated that the highest resistance rate was related to piperacillin-tazobactam (n=25, 41.6%), followed by and meropenem (n=17, 28.8%) and cotrimoxazole (n=11, 18.3%), respectively. Also, all strains were susceptible to amikacin, gentamicin, and imipenem. The PCR results of the virulence gene showed that 95% (n=57) of isolates were positive for fimH gene, 93.33% (n=56) for BssS gene, 27 (45%) for rmpA gene. The PCR results for antibiotic resistance genes showed that 41.66% (n=25) had blaTEM gene, 38.33% (n=23) blaCTX-M gene, 35% (n=21) blaSHV gene and 3.33% (n=2) isolates had blaKPC gene, and none of these isolates carried magA gene. Conclusion: Antibiotic resistance was common among K. pneumoniae isolated from healthy volunteers' feces who participated in this study. Transmission of resistant bacteria and plasmids through oral-fecal sources threats to the public, which could complicate treatment options for community-acquired infections caused by K. pneumoniae.

C I T A T I O N L I N K S A R T I C L E I N F O Article Type Original Research Authors Shivaee A.... more C I T A T I O N L I N K S A R T I C L E I N F O Article Type Original Research Authors Shivaee A.1MSc, Mirshekar M.1PhD, Mohammadzadeh R. 1MSc, Shahbazi Sh. 2* PhD How to cite this article Shivaee A, Mirshekari M, Mohammadzadeh R, Shahbazi Sh. Association between ESBLs Genes and quinolone Resistance in Uropathogenic Escherichia coli Isolated from Patients with Urinary Tract Infection. Infection Epidemiology and Microbiology. 2019;5(1):15-23 1Department of Microbiology, Faculty of Medicine, Iran university of Medical Science, Tehran, Iran 2Department of Molecular Biology, Pasteur Institute of Iran, Pasteur Ave., Tehran 13164, Iran * Correspondence Address: Pasteur Institute of Iran, Pasteur Square, Tehran, Iran. Postal Code: 1316943551 Phone: Shahbazi.shahla@yahoo.com Article History Received: February 2019 ,20 Accepted: March 2019 ,14 ePublished: May 2019 ,30 [1] Acinetobacter baumannii: Evolution of a global pathogen... [2] Dunitz M. Urinary Tract Infection in the Female... [3] Mar...

Medical Journal of the Islamic Republic of Iran, 2020