Publications by authors named "Masoumeh Douraghi"

55 Publications

In silico analysis of STX2a-PE15-P4A8 chimeric protein as a novel immunotoxin for cancer therapy.

In Silico Pharmacol 2021 10;9(1):19. Epub 2021 Feb 10.

Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Science, Tehran, Iran.

Today, the targeted therapies like the use of immunotoxins are increased which targeted specific antigens or receptors on the surface of tumor cells. Fibroblast growth factor-inducible 14 (Fn14) is a cytokine receptor which involves several intercellular signaling pathways and can be highly expressed in the surface of cancer cells. Since the cleavage of enzymatic domain of (PE) occurs in one step by furin protease, we fused enzymatic subunit of Shiga-like toxin type 2a (Stx2a) with domain II and a portion of Ib of PE to increase the toxicity of Stx. Then, we genetically fused the Fv fragment of an anti-Fn14 monoclonal antibody (P4A8) to STX2a-PE15 and evaluated the STX2a-PE15-P4A8 chimeric protein as a new immunotoxin candidate. In silico analysis showed that the STX2a-PE15-P4A8 is a stable chimeric protein with high affinity to the Fn14 receptor. Despite, the STX2a-PE15-P4A8 can be bind to the B cell receptor, but it has been weakly presented by major histocompatibility complex molecules II (MHC-II). So, it may have a little immunogenicity. On the basis of our in-silico studies we predict that STX2a-PE15-P4A8 can be a good candidate for cancer immunotherapy.

Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-021-00079-w.
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http://dx.doi.org/10.1007/s40203-021-00079-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7876190PMC
February 2021

Isolation and characterization of a multidrug-resistant toxinotype V from municipal wastewater treatment plant.

J Environ Health Sci Eng 2020 Dec 26;18(2):1281-1288. Epub 2020 Sep 26.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, PO Box: 14155-6446, Tehran, Iran.

Purpose: Wastewater treatment plant (WWTP) is regarded as a potential source for transmission of from urban areas into the surface water, through feces of human and animals. The aim of this study was to screen and characterize the bacteria in inlet and outlet wastewater of different WWTPs in Tehran, Iran.

Methods: Totally, 72 samples were collected from three different WWTPs (inlet site and outlet sites) during a year. was isolated and characterized in terms of toxins, toxinotype, resistance profile and genes, and colonization factors using PCR.

Results: One toxinotype V was isolated from the outlet samples. The isolate was susceptible to vancomycin but resistant to metronidazole, tetracycline, ciprofloxacin, and moxifloxacin using MIC Test Strips. The isolated was toxigenic (, , , positive and CPE positive) and had genotype. No mutations were found in and . The sequence type was 078 - 01. The was positive for , , but negative for , , and genes. Mutations were not observed in and genes.

Conclusions: This study provided evidence of presence of a multidrug-resistant toxinotype V in one of the municipal WWTP. The transmission of such isolate to the environment and reuse of treated wastewater by human pose a threat to human health and dissemination of antibiotic resistant bacteria which are untreatable.
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http://dx.doi.org/10.1007/s40201-020-00546-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721768PMC
December 2020

Distribution of smf-1, rmlA, spgM and rpfF genes among Stenotrophomonas maltophilia isolates in relation to biofilm-forming capacity.

J Glob Antimicrob Resist 2020 12 31;23:321-326. Epub 2020 Oct 31.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

Objectives: The molecular mechanisms involved in biofilm formation inStenotrophomonas maltophilia are poorly understood. Here, we examined whether the presence of smf-1, rmlA, spgM and rpfF genes is associated with biofilm formation and antibiotic resistance in S. maltophilia.

Methods: A total of 150 S. maltophilia isolates were collected from three tertiary-care hospitals in Iran and were identified through PCR amplification of the 23S rRNA gene. Biofilm formation was determined by microtitre plate assay. Presence of smf-1, rmlA, spgM and rpfF genes was examined by PCR.

Results: Among the isolates examined, 148 (98.7%) were able to produce biofilm, of which 69 (46.0%) were strong biofilm-producers, whereas 32 (21.3%) and 47 (31.3%) were moderate and weak biofilm-producers, respectively. The frequency ofsmf-1, rmlA, spgM and rpfF was 99.3%, 98.0%, 97.3% and 70.0%, respectively. Statistical analysis indicated a direct correlation between presence of the rpfF gene and biofilm formation (P < 0.001). The high prevalence of smf-1 (99.3%) among the isolates is noted and there was a significant association between smf-1 and biofilm-forming ability (P < 0.01), but lower than rpfF. Additionally, a direct association was found between resistance to ticarcillin/clavulanate, ceftazidime, ciprofloxacin and doxycycline and strong biofilm formation in the S. maltophilia isolates (P < 0.01).

Conclusion: This study demonstrated thatS. maltophilia clinical isolates significantly differ in biofilm-forming ability. Moreover, presence of rpfF and smf-1, but not spgM, could be associated with biofilm formation. This study highlights the importance of rpfF in formation of biofilm compared with the other genes involved.
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http://dx.doi.org/10.1016/j.jgar.2020.10.011DOI Listing
December 2020

Polymorphisms in the genes encoding surface associated proteins of Clostridioides difficile isolates.

Infect Genet Evol 2020 12 17;86:104598. Epub 2020 Oct 17.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

Background: Although the diversity of Clostridioides difficile toxins have been extensively studied, little is known about the variation in the surface associated proteins (SAPs) which are important in early steps of bacterial colonization and infection. Here, we examined 65C. difficile isolates to identify polymorphisms in the genes encoding SAPs.

Methods: PCR was used to amplify slpA, fliC, fliD, cwp66 and cwp84 genes, followed by sequencing. In addition, the antigenicity and immunogenicity properties of different types of SlpA, FliC, FliD, Cwp66 and Cwp84 proteins were predicted in-silico by VaxiJen and BcePred online servers.

Results: The predominant slpA sequence type was gr-01 (42.37%), followed by hr-01 (11.86%) and 078-01 (10.16%). In addition, two new slpA subtypes of smz (smz-09-Ir and smz-010-Ir) and a new slpA sequence type (Ir-01) were identified among the isolates examined. Analysis of the nucleotide sequences of fliC, fliD, cwp66 and cwp84 genes revealed 7, 5,5,3 different sequence types, respectively. Insilico analysis of antigenicity of SAPs showed that FliC had the highest level of antigenicity whereas SlpA and Cwp66 proteins had the highest level of immunogenicity.

Conclusions: This study pointed to the nucleotide polymorphism in SAPs of C. difficile isolates and demonstrated noticeable diversity in antigenicity and immunogenicity of these proteins which need to be taken into consideration as promising therapeutic or vaccine targets.
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http://dx.doi.org/10.1016/j.meegid.2020.104598DOI Listing
December 2020

Spoligotype and Drug Susceptibility Profiles of Complex Isolates in Golestan Province, North Iran.

Infect Drug Resist 2020 1;13:2073-2081. Epub 2020 Jul 1.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Introduction: Despite the moderate incidence of tuberculosis (TB) in many parts of Iran, Golestan province had a permanently higher TB incidence rate than the national average. Moreover, Golestan province receives immigrants, mainly from TB-endemic areas of Iran and neighbor countries. Here, we aimed to characterize the circulating complex (MTBC) isolates in terms of the spoligotype and drug resistance patterns, across Golestan province.

Materials And Methods: A set of 166 MTBC isolates was collected during July 2014 to July 2015 and subjected to drug susceptibility testing for first- and second-line anti-TB drugs and spoligotyping.

Results: Of 166 MTBC isolates, 139 (83.7%) isolates were assigned to 28 spoligotype international types (SITs). The most frequent SITs were SIT127/Ural-2 (n=25, 15.1%), followed by SIT1/Beijing (n=21, 12.7%) and SIT3427/Ural-2 (n=18, 10.8%). The set of 18 isolates (10.8%) showed resistance to at least one drug, which mainly belonged to SIT1/Beijing (n=7, 38.9%), orphan patterns (n=4, 22.2%) and SIT357/CAS1-Delhi (n=3, 16.7%). In addition, four isolates (2.4%) were resistant to pyrazinamide. The analysis of mutation corresponded to resistance to rifampin and isoniazid showed that two isolates had Ser531Leu substitution in B, four isolates had Ser315Thr substitution in G and one isolate had [C(-15)T] in A locus.

Conclusion: High diversity in spoligotypes of the MTBC isolates and lack of dominant genotype might be due to residence of immigrants in this region and consequent reactivation of latent infection. In addition, due to the presence of extensively drug-resistant (XDR) isolates in Golestan province, it is important to conduct future studies to determine transmission pattern of drug-resistant isolates in this region.
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http://dx.doi.org/10.2147/IDR.S255889DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7335844PMC
July 2020

Accumulation of Antibiotic Resistance Genes in Carbapenem-Resistant Isolates Belonging to Lineage 2, Global Clone 1, from Outbreaks in 2012-2013 at a Tehran Burns Hospital.

mSphere 2020 04 8;5(2). Epub 2020 Apr 8.

The ithree institute, University of Technology Sydney, Ultimo, New South Wales, Australia

The worldwide distribution of carbapenem-resistant (CRAB) has become a global concern, particularly in countries where antibiotic prescription is not tightly regulated. However, knowledge of the genomic aspects of CRAB from many parts of the world is still limited. Here, 50 carbapenem-resistant isolates recovered at a single hospital in Tehran, Iran, during several outbreaks in 2012 and 2013 were found to be resistant to multiple antibiotics. They were examined using PCR mapping and multilocus sequence typing (MLST). All Iranian strains belonged to sequence type 328 in the Institut Pasteur MLST scheme (ST328), a single-locus variant of ST81 and all Iranian strains contained two carbapenem resistance genes, and The gene is in the transposon Tn in AbaR4, which interrupts the chromosomal gene. Phylogenetic analysis using whole-genome sequence (WGS) data for 9 isolates showed that they belonged to the same clade, designated the ST81/ST328 clade, within lineage 2 of global clone 1 (GC1). However, there were two groups that included either KL13 or KL18 at the K locus (KL) for capsular polysaccharide synthesis and either a or an resistance gene, respectively. The genetic context of the resistance genes was determined, and the (OXA-72 variant) and (tetracycline resistance) genes were each in a p module in different plasmids. The gene cassette (which encodes gentamicin, kanamycin, and tobramycin resistance) was harbored by pRAY*, and the gene (which encodes amikacin resistance) and gene (which encodes sulfamethoxazole resistance) were each harbored by a different plasmid. The sequences obtained here will underpin future studies of GC1 CRAB strains from the Middle East region. Carbapenem-resistant strains are among the most critical antibiotic-resistant bacteria causing hospital-acquired infections and treatment failures. The global spread of two clones has been responsible for the bulk of the resistance, in particular, carbapenem resistance. However, there is a substantial gap in our knowledge of which clones and which specific lineages within each clone are circulating in many parts of the world, including Africa and the Middle East region. This is the first genomic analysis of carbapenem-resistant strains from Iran. All the isolates, from a single hospital, belonged to lineage 2 of global clone 1 (GC1) but fell into two groups distinguished by genes in the locus for capsule biosynthesis. The analysis suggests a potential origin of multiply antibiotic-resistant lineage 2 in the Middle East region and highlights the ongoing evolution of carbapenem-resistant GC1 strains. It will enhance future studies on the local and global GC1 population structure.
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http://dx.doi.org/10.1128/mSphere.00164-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142300PMC
April 2020

High prevalence of Clostridiodes diffiicle PCR ribotypes 001 and 126 in Iran.

Sci Rep 2020 03 13;10(1):4658. Epub 2020 Mar 13.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Clostridium difficile is a leading causative agent of hospital-acquired and community-acquired diarrhea in human. This study aims to characterize the predominant C. difficile strains, RT001 and 126, circulating in Iranian hospitals in relation to resistant phenotypes, the antibiotic resistance genes, and their genetic relatedness. A total number of 735 faecal specimens were collected from patients suspected of CDI in Tehran hospitals. Typing and subtyping of the strains were performed using CE-PCR ribotyping and MLVA, respectively, followed by PCR assays for ARGs and indicators of Tns. Minimum inhibitory concentrations (MICs) of five antibiotics were determined by MIC Test Strips. Among 65 strains recovered from CDI patients, RT001 (32.3%) and RT126 (9.2%) were found as the most frequent ribotypes, and 64 MLVA types were identified. Using MLVA, RT001 and RT126 were subtyped into 6 and 4 groups, respectively. The vanA, nim, tetM, gyrA, gyrB genes were detected in 24.6%, 0%, 89.2%, 95.3%, and 92.3% of the strains, respectively. The indicators of Tns including vanHAX, tndX, and int were found in 0%, 3% and 29.2% of the strains, respectively. The most common amino acid (AA) alterations of GyrA and GyrB were related to substitutions of Thr82 → Val and Ser366 → Val, respectively. Resistance rate to metronidazole, vancomycin, tetracycline, ciprofloxacin, and moxifloxacin was 81.5%, 30.7%, 85%, 79%, and 74%, respectively. This study, for the first time revealed the subtypes of circulating RT001 and RT126 in Iran. It is of importance that the majority of the strains belonging to RT001 were multidrug resistant (MDR). This study also pointed to the intra-hospital dissemination of the strains belonging to RT001 and RT126 for short and long periods, respectively, using MLVA. The most important resistance phenotypes observed in this study was vancomycin-resistant phenotypes. Resistance to metronidazole was also high and highlights the need to determine its resistance mechanisms in the future studies.
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http://dx.doi.org/10.1038/s41598-020-61604-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070088PMC
March 2020

Phage Therapy as an Approach to Control Salmonella enterica serotype Enteritidis Infection in Mice.

Rev Soc Bras Med Trop 2019 14;52:e20190290. Epub 2019 Nov 14.

Division of Medical Bacteriology, Department of Pathobiology, School of Public Health (TUMS), Tehran, Iran.

Introduction: Salmonella enterica serotype Enteritidis (S. Enteritidis) is a cause of food-borne human illness. Given the prevalence of antibiotic resistance of Salmonella Enteritidis and the lack of antibiotic efficacy in future years, its replacement with other agents is necessary. One of the most useful agents is bacteriophages.

Methods: S. Enteritidis was identified using a multiplex polymerase chain reaction assay. The effective bacteriophages were isolated from hospital wastewater samples. The effects of the bacteriophages were evaluated both in vitro and in vivo.

Results: The phage SE20 belonged to the Podoviridae family, and the genome size was 40 kb. The evaluation of phage SE20 at variable pH ranges showed its susceptibility to pH < 3 and pH > 12. The animal model showed that mice infected with S. Enteritidis developed hepatomegaly and splenomegaly, but did not experience gastrointestinal complications after receiving the bacteriophages.

Conclusions: The results of this study suggest that phage SE20 is a promising candidate for controlling salmonellosis caused by Salmonella Enteritidis.
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http://dx.doi.org/10.1590/0037-8682-0290-2019DOI Listing
January 2020

Amikacin resistance due to the aphA6 gene in multi-antibiotic resistant Acinetobacter baumannii isolates belonging to global clone 1 from Iran.

BMC Microbiol 2019 09 18;19(1):221. Epub 2019 Sep 18.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, PO Box: 14155-6446, Tehran, Iran.

Background: TnaphA6-carrying repAci6 plasmids have been detected in Acinetobacter baumannii isolates belonging to global clones, GC1 and GC2, worldwide. Here, we examined whether RepAci6 plasmids family play a role in the dissemination of the aphA6 in GC1 A. baumannii isolates from Iran.

Results: We found that 22 isolates carried the repAci6 gene, suggesting that they contain a RepAci6 plasmid family. Using the primers linking the aphA6 gene to the backbone of repAci6 plasmid, it was revealed that 16 isolates from different hospitals harbored TnaphA6 on a repAci6 plasmid.

Conclusions: This study provides evidence for the dissemination of TnaphA6 on the plasmids encoding RepAci6 in Iranian A. baumannii isolates. Furthermore, it seems that TnaphA6 might be acquired by distinct plasmids separately as it was found to be located on the variants of repAci6 plasmids.
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http://dx.doi.org/10.1186/s12866-019-1592-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751817PMC
September 2019

Propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assay for rapid detection of viable and viable but non-culturable (VBNC) in swimming pools.

J Environ Health Sci Eng 2019 Jun 7;17(1):407-416. Epub 2019 Mar 7.

1Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Lack of culturability in the viable but non-culturable (VBNC) bacteria and the ability to regain infectivity in favourable conditions is one of the new challenges of public health providers for monitoring in environmental samples. Propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) is one of the promising methods for timely detection of VBNC pathogens in environmental samples. We developed and used a method for the first time to detection of VBNC in swimming pool water samples using a membrane filter (MF). Moreover, the dominant model of the distribution of colonies on the MF and the effect of the culture medium and MF type on colony recovery by MF were evaluated. Swimming pool samples were subjected to conventional culture-based, qPCR and PMA-qPCR methods and the results were compared for the presence of VBNC in the samples. The positivity rate was 21% and 75% for in water samples as confirmed by standard culture-based and qPCR methods, respectively. Furthermore, of 24 samples, 9 (37.5%) were positive for VBNC . The developed qPCR/PMA-qPCR assay can detect the VBNC bacteria directly from aquatic samples and may result in better monitoring of recreational waters.
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http://dx.doi.org/10.1007/s40201-019-00359-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6582174PMC
June 2019

Characterization of Clostridioides difficile isolates recovered from hospitalized patients and the hospitals environment and air: A multicenter study.

Anaerobe 2019 Oct 25;59:154-158. Epub 2019 Jun 25.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

In healthcare settings, contamination of environment with toxigenic and hypervirulent Clostridioides difficile strains is a serious concern. Here, we assessed whether patients with C. difficile have a role to play in the dissemination of C. difficile in our settings or other sources are implicated in its circulation. A total of 700 fecal specimens and 1435 environmental samples from surfaces, equipment and air of rooms occupied by patients suspected of C. difficile infection were taken from 4 tertiary hospitals in Tehran, Iran between April 2016 and August 2017. Antibiotic susceptibility testing and detection of resistance genes were performed for the environmental isolates. The clinical and environmental isolates of C. difficile were subjected to Pulsed Field Gel Electrophoresis (PFGE) analysis. Forty three (6.14%) and 2 (0.13%) isolates of C. difficile were recovered from the clinical and environmental samples, respectively. In the clinical settings, 2 patients were suspected of recurrent C. difficile infection. Thirty distinct pulsotypes were found among the C. difficile isolates including 28 singletons and 2 common types. One of the two environmental isolates was isolated from floor in the Medical ward, of pulsotype/ribotype/toxinotype PT10/New ribotype/toxinotype V, harbored cdtA/B and tcdC-A, and resistant to ciprofloxacin. The other one was isolated from air of a room in ICU, assigned to PT11/RT001/toxinotype 0, belonged to tcdC-sc3 genotypes and resistant to metronidazole. The environmental isolates did not generate amplicons in PCR assays targeting vanA and nim genes. This study provided evidence for dissemination of genetically diverse strains of C. difficile in hospitalized patients, presence of C. difficile in hospital air, existence of binary toxin positive/antibiotic-resistant isolate on the floor and intra-hospital dissemination of this pathogen.
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http://dx.doi.org/10.1016/j.anaerobe.2019.06.012DOI Listing
October 2019

Real-time polymerase chain reaction assays for rapid detection and virulence evaluation of the environmental Pseudomonas aeruginosa isolates.

Mol Biol Rep 2019 Aug 15;46(4):4049-4061. Epub 2019 May 15.

Center for Water Quality Research (CWQR), Institute for Environmental Research (IER), Tehran University of Medical Sciences, Tehran, Iran.

Rapid and species-specific detection, and virulence evaluation of opportunistic pathogens such as Pseudomonas aeruginosa, are issues that increasingly has attracted the attention of public health authorities. A set of primers and hydrolysis probe was designed based on one of the P. aeruginosa housekeeping genes, gyrB, and its specificity and sensitivity was evaluated by TaqMan qPCR methods. The end point PCR and SYBR Green qPCR were used as control methods. Furthermore, multiplex RT-qPCRs were developed for gyrB as reference and four virulence genes, including lasB, lasR, rhlR and toxA. Totally, 40 environmental samples, two clinical isolates from CF patients, two standard strains of P. aeruginosa, and 15 non-target reference strains were used to test the sensitivity and specificity of qPCR assays. In silico and in vitro cross-species testing confirmed the high specificity and low cross-species amplification of the designed gyrB418F/gyrB490R/gyrB444P. The sensitivity of both TaqMan and SYBR Green qPCRs was 100% for all target P. aeruginosa, and the detected count of bacteria was below ten genomic equivalents. The lowest M value obtained from gene-stability measurement was 0.19 that confirmed the suitability of gyrB as the reference gene for RT-qPCR. The developed qPCRs have enough detection power for identification of P. aeruginosa in environmental samples including clean and recreational water, treated and untreated sewage and soil. The short amplicon length of our designed primers and probes, alongside with a low M value, make it as a proper methodology for RT-qPCR in virulence genes expression assessment.
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http://dx.doi.org/10.1007/s11033-019-04855-yDOI Listing
August 2019

Rapid Simultaneous Molecular Stool-Based Detection of Toxigenic Clostridioides difficile by Quantitative TaqMan Real-Time PCR Assay.

Clin Lab 2019 Apr;65(4)

Background: Clostridioides difficile is a major cause of nosocomial infectious diarrhea in hospitalized patients throughout the world.

Methods: A multiplex real-time PCR assay was developed and evaluated in comparison with toxigenic culture (TC) (as gold standard method) for direct detection of toxigenic C. difficile in fecal specimens. The multiplex real-time PCR assay simultaneously detected glutamate dehydrogenase (gluD), toxin A (tcdA), toxin B (tcdB), and binary toxin (cdtB) genes in stool samples.

Results: The results of multiplex real-time PCR were compared to those of the TC method in 250 patients suspected of C. difficile infection. The prevalence of positive TC was 13.6%. Forty-two stool samples (16.8%) were determined to be gluD+ using multiplex real-time PCR. These included 35 (83.3%) toxigenic (32 tcdA+, tcdB+ and three tcdB+) and 7 (20.0%) were cdtB+. The multiplex real-time PCR assay had a sensitivity of 91.45%, specificity of 99.54%, and positive and negative predictive values of 97% and 98.6%, respectively, compared to the TC method for diagnosis of C. difficile. The analytical sensitivity of the multiplex real-time PCR assay was estimated to be 102 CFU/g of stools and 0.0200 pg of genomic DNA from culture. The analytical specificity was determined to be 100% by using enteric and non-C. difficile standard bacterial strains.

Conclusions: The molecular method developed in the study was rapid, sensitive, and specific for detection of toxigenic C. difficile. It is applicable to be performed in clinical laboratories and correlated well with the results obtained by TC.
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http://dx.doi.org/10.7754/Clin.Lab.2018.180735DOI Listing
April 2019

Tetracycline and ciprofloxacin multiresidues in beef and chicken meat samples using indirect competitive ELISA.

J Immunoassay Immunochem 2019 4;40(3):328-342. Epub 2019 Apr 4.

a Division of Microbiology, Department of Pathobiology, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran.

In livestock and poultry, broad-spectrum antibiotics such as tetracyclines and fluoroquinolones are widely used; thus, controlling food productions made from these animals is a necessary task. Meat may contain residues of antibiotics, even in low concentrations, which can cause a selection pressure for antibiotic resistance. Therefore, measurement of amounts of antibiotics in meat is of major importance. A total of 41 beef and 41 chicken meat samples were collected for 1 year. Tetracycline and ciprofloxacin were extracted from samples and tested by an indirect competitive enzyme-linked immunosorbent assay. Overall, 100% of the beef and more than 95% of the chicken meat samples were positive for ciprofloxacin. Only one of the chicken meat samples had concentrations of ciprofloxacin higher than maximum residue limit (MRL). For ciprofloxacin, none of the beef meat samples exceeded the MRL. For tetracycline, 75% of the beef and 58% of the chicken meat samples were positive. All of the samples had concentrations of tetracycline lower than MRL. It was revealed that the chicken meat samples had higher levels of both antibiotics than those of beef samples. The amounts of tested antibiotics were not high in the meat samples, consequently using of beef and chicken meat by consumers in Iran is not resulted in entrance of high amounts of the antibiotics into human body.
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http://dx.doi.org/10.1080/15321819.2019.1597735DOI Listing
June 2019

Epidemiological linkage of vancomycin-resistant Enterococcus faecium from different sources in Ahwaz, Iran.

FEMS Microbiol Lett 2019 03;366(6)

Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran 1417653761, Iran.

This study was set to determine the genetic linkage and the clonal relationship between vancomycin-resistant Enterococcusfaecium (VREfm) isolates in three hospitals of Ahwaz city. In this study, 1050 samples were collected from various rectal swabs, hands of health care workers, environmental surfaces, medical equipment and 146 enterococci isolates from clinical sources of three hospitals from March to September 2015. Antimicrobial resistance patterns in VREfm were detected by disk diffusion method. Genetic linkages of VREfm strains were investigated by pulse field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) methods. Out of 366 enterococcal isolates, 163 Enterococcus faecium isolates were found to be resistant to vancomycin. PFGE and MLST analysis showed the presence of 79 pulsotypes and 11 sequence types (ST), respectively. In total, 90% of the isolates belonged to clonal complex 17 (CC17). Three new STs were reported for the first time in this study and ST80 was the predominant ST. We found a high prevalence of diverse VREfm with threatening antibiotic resistance patterns in all the studied sources with the dominance of CC17 VREfm strains in Ahwaz hospitals. Also, the results of typing method showed inter- and intra-hospital circulation of VREfm and similar pulsotypes and STs among different sources.
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http://dx.doi.org/10.1093/femsle/fnz062DOI Listing
March 2019

Molecular typing of Clostridioides difficile isolates from clinical and non-clinical samples in Iran.

APMIS 2019 Apr;127(4):222-227

Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.

Clostridioides difficile is a major cause of nosocomial infectious diarrhea in hospitalized patients throughout the world. We aimed to characterize C. difficile isolates among hospitalized patients, hospital staffs, and hospital environment samples obtained in three tertiary care hospitals of Iran with regard to their molecular types between June 2016 and November 2017. The toxigenicity of C. difficile isolates was determined by toxigenic culture and multiplex-PCR. Toxigenic C. difficile isolates collected were ribotyped using capillary gel electrophoresis-based PCR and the database of WEBRIBO (http://webribo.ages.at). Of 500 clinical and non-clinical samples, toxigenic C. difficile were identified in 35 of 250 stool samples (14%) and in 3 of 250 swabs (1.2%). The most frequently found ribotypes (RTs) were 039, AI-12, and AI-21 (15.8, 10.52, and 10.52% of all isolates, respectively). Further RTs were: 017, 001, AI-3, AI-15, AI-18, AI-10, AI-4, and PR21195 (as new ribotype). The epidemic RTs (027 and 078) seen in the Europe, North America, and Asia were completely absent in this study.
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http://dx.doi.org/10.1111/apm.12937DOI Listing
April 2019

The emergence of metronidazole and vancomycin reduced susceptibility in Clostridium difficile isolates in Iran.

J Glob Antimicrob Resist 2019 09 28;18:28-33. Epub 2019 Jan 28.

Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Electronic address:

Objectives: Clostridium difficile (C. difficile) is the main causative agent of antibiotic-associated diarrhoea (AAD) and pseudomembranous colitis. The accumulation of antimicrobial resistance in C. difficile strains can drive C. difficile infection (CDI) epidemiology. This study was undertaken to evaluate the antimicrobial resistance patterns of toxigenic C. difficile isolates cultured from diarrhoeal stool samples of hospitalised patients with suspected CDI in three tertiary care hospitals in Tehran, Iran.

Methods: Two hundred and fifty diarrhoeal stool samples were investigated by toxigenic culture using cycloserine-cefoxitin-fructose agar and the VERO cell line. Antimicrobial susceptibility to metronidazole, vancomycin, clindamycin, tetracycline, and moxifloxacin was performed by disk diffusion and Etest methods on Brucella Blood Agar supplemented with hemin and vitamin K.

Results: Thirty-five stool samples (14.0%) proved positive using C. difficile toxigenic culture. According to Clinical and Laboratory Standards Institute breakpoints, the following resistance was identified in C. difficile isolates: metronidazole (2 of 35); moxifloxacin (7 of 35); clindamycin (18 of 35); and tetracycline (5 of 35). Using European Committee on Antimicrobial Susceptibility Testing breakpoints, three of 35 isolates showed reduced-susceptibility for vancomycin and 14 of 35 for metronidazole. In addition, the results showed a good correlation between the inhibition zone diameter (disk diffusion) and MIC values (Etest); Pearson correlation coefficient 0.7400.95 (P< 0.001).

Conclusions: Multidrug resistance was observed in Iranian clinical toxigenic C. difficile isolates, including reduced susceptibility to first-line CDI treatment drugs. In addition, disk diffusion can be used as a cost-effective option for the antimicrobial susceptibility testing of C. difficile isolates.
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http://dx.doi.org/10.1016/j.jgar.2019.01.027DOI Listing
September 2019

Genetic diversity of Mycobacterium tuberculosis complex isolates circulating in an area with high tuberculosis incidence: Using 24-locus MIRU-VNTR method.

Tuberculosis (Edinb) 2018 09 4;112:89-97. Epub 2018 Aug 4.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

We aimed to determine the genetic diversity, phylogenetic relationship and transmission dynamics of Mycobacterium tuberculosis complex (MTBC) genotypes in an area with high tuberculosis (TB) incidence. A set of 164 MTBC isolates from new TB patients of Golestan province, Iran, were subjected to genotyping using the standard 24-locus MIRU-VNTR method. Recent TB transmission was evaluated and phylogenetic relationships were analysed by minimum spanning tree and cluster-graph methods. Among the 164 isolates, 132 distinct patterns were detected. The 48 clustered isolates (29.3%) were distributed into 16 clusters ranging in size from 2 to 12 isolates. The most frequent genotype was Central Asian Strain/Delhi (CAS/Delhi) (n = 67, 40.8%), followed by NEW-1 (n = 53, 32.3%) and Beijing (n = 19, 11.6%) genotypes. Thirty five (72.9%) of NEW-1 isolates were recovered from immigrant patients and 84.2% (n = 16) of Beijing genotypes recovered from native cases. Statistically significant association was found between clustering and smoking (p = 0.047), drug addiction (p = 0.01) and prison history (p = 0.003). The estimated proportion of recent transmission was 19.5%. Presence of highly diverse MTBC isolates circulating in this province without a dominant genotype might be a consequence of importation of various genotypes in this area.
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http://dx.doi.org/10.1016/j.tube.2018.08.003DOI Listing
September 2018

Isolation and identification of specific bacteriophage against enteropathogenic Escherichia coli (EPEC) and in vitro and in vivo characterization of bacteriophage.

FEMS Microbiol Lett 2018 08;365(16)

Department of Biostatistics, Faculty of medical sciences, Tarbiat Modares University, Tehran 3551713146, Iran.

In recent years, the increasing resistance of enteropathogenic Escherichia coli (EPEC) to commonly used antibiotics has made it difficult to choose the best treatment option. Bacteriophage therapy could be a potent alternative to antibiotic therapy for antibiotic-resistant bacteria. The aim of the present study was to isolate and identify a specific bacteriophage against EPEC and characterize bacteriophage in vitro and in vivo. The specific bacteriophage was isolated, and the effect of phage therapy on 48 mice (Balb/c) was investigated. Animals were divided into six groups, including A: PBS (negative control); B: bacteria (positive control); C: bacteria + ciprofloxacin (after 24 h); D: bacteria + bacteriophage (after 24 h); E: bacteria + ciprofloxacin + bacteriophage (after 24 h) and F: bacteriophage + bacteria (after 24 h). Specific bacteriophage against EPEC was isolated from hospital sewage. The bacteriophage had an icosahedral head (120 nm) and a tail (138 nm). The single dose of the bacteriophage (2 × 109 pfu ml-1) was able to control the infection. Unfortunately, because of the misuse of antibiotics by EPEC infected patients, the antibiotic resistant bacteria will become prevalent in the future and the treatment of EPEC infection is going to become more difficult than ever.
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http://dx.doi.org/10.1093/femsle/fny136DOI Listing
August 2018

Investigation of the Cellular Immune Response to Recombinant Fragments of Filamentous Hemagglutinin and Pertactin of Bordetella pertussis in BALB/c Mice.

J Interferon Cytokine Res 2018 04;38(4):161-170

1 Department of Immunology, Tehran University of Medical Sciences , Tehran, Iran .

Vaccination with whole-cell or acellular (Ac) vaccines has been very effective for the control of pertussis. The immune response to Ac vaccines has been generally associated with a shift toward the Th2 profile. In the present study, overlapping recombinant fragments of filamentous hemagglutinin (FHA) and pertactin (PRN) were produced in Escherichia coli. BALB/c mice were immunized with recombinant FHA and PRN together with the native pertussis toxin and alum or CpG as adjuvant. Immunized mice were subsequently aerosol challenged with Bordetella pertussis. Bacterial growth was assessed in bronchoalveolar lavage samples and the levels of cytokines were quantitated in supernatants of stimulated splenocytes by enzyme-linked immunosorbent assay. Our results demonstrated that both PRN and FHA antigens were able to induce IFN-γ, IL-4, and to some extent IL-17 cytokines in challenged mice. The level of IFN-γ was higher in response to CpG formulated antigens. These findings indicate immunoprotective efficacy of our recombinant FHA and PRN antigens in mice.
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http://dx.doi.org/10.1089/jir.2017.0060DOI Listing
April 2018

Molecular analysis of integrons and antimicrobial resistance profile in Shigella spp. isolated from acute pediatric diarrhea patients.

GMS Hyg Infect Control 2018 31;13:Doc02. Epub 2018 Jan 31.

Forensic Medicine, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.

spp. is a growing global health concern due to increasing multiple drug resistance, commonly resulting in therapeutic failure. Integrons are gene expression systems run by integrase genes. The aims of this study were detection of class I, II and III integrons and assessment of antimicrobial resistance in spp. isolated from acute pediatric diarrhea patients. From January to December 2015, 16 spp. were isolated from 310 non-duplicative diarrheal stool samples in Children's Medical Center, Tehran, Iran. The isolates were analyzed for their antibiotic susceptibility using CLSI guidelines M100-S14. Multiplex PCR was used for amplification of I, II and III integron-associated integrase () genes. Of 310 stool samples, 16 (5.2%) were positive for spp., in 7 of them and in 9 of them were identified. Results of the antimicrobial susceptibility test showed that 6.2%, 50%, 31.2%, 6.2%, 81.2%, 56.2% and 31.2% of the isolates were resistant to gentamicin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, ampicillin and trimethoprim-sulfamethoxazole, respectively. Multiplex PCR results revealed that 6.2% (1/16), 31.2% (5/16), 50% (8/16) of isolates carried I, iII and both I/lI genes. No class 3 integrons were detected. In this study, multidrug resistance was seen in isolates similar to that in isolates from other geographical areas. This is possible due to inappropriate use of antimicrobials. Furthermore, prevalence of multidrug resistance was significantly linked to the presence of integrin genes. A class 2 integron plays a role in presence of multidrug resistance in spp. It is vital to prevent the spread of antibiotic resistance through continuous monitoring.
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http://dx.doi.org/10.3205/dgkh000308DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5804674PMC
January 2018

Mycobacterium tuberculosis Complex Drug Resistance in a High Tuberculosis Incidence Area from the WHO Eastern Mediterranean Region.

J Pharm Pharm Sci 2017 ;20(1):428-434

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Purpose: The incidence of tuberculosis (TB) in Golestan province of Iran has been ranked 10th among countries of World Health Organization (WHO) Eastern Mediterranean Region. The province is residence of ethnically heterogeneous groups. However, there are limited data on Mycobacterium tuberculosis drug resistance in this province. The main aim of this study was to determine the resistance profile of M. tuberculosis complex (MTBC) isolates to first-line anti-TB drugs.

Methods: The clinical specimens were collected from 11807 cases diagnosed during this study. MTBC isolates were tested for susceptibility to first-line anti-TB drugs.

Results: A total of 176 new cases were diagnosed as culture positive for MTBC. There was one case that had multidrug-resistant (MDR) isolate and 18 (10.2%) had isolates that were resistant to at least one drug (any drug resistant). Resistance to streptomycin and isoniazid was noted in 15 (8.5%) and 5 isolates (2.8%), respectively. Also, a statistically significant association was observed between age groups and any drug resistance pattern (p = 0.022): 1-24 years vs. 25-45 years (p = 0.033), 25-45 years vs. >65 years (p = 0.010), 46-65 years vs. >65 years (p = 0.050). One third of any drug resistant isolates were obtained from TB patients of Persian ethnic group.

Conclusion: Despite the high incidence of TB, the rate of MDR-TB in Golestan province was similar to those reported by WHO for Iranian new cases from other regions. One-tenth of the studied isolates showed any drug resistance pattern. This rate of any drug resistance implies the possibility of initial resistance of MTBC isolates circulating in this region.
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http://dx.doi.org/10.18433/J3J64HDOI Listing
July 2018

Evaluation the cytotoxic effect of cytotoxin-producing Klebsiella oxytoca isolates on the HEp-2 cell line by MTT assay.

Microb Pathog 2017 Dec 14;113:416-420. Epub 2017 Nov 14.

Department of Microbiology, Qazvin University of Medical Sciences, Qazvin, Iran.

Background: The cytotoxic effects on epithelial cells of the human are not observed in other strains of Klebsiella spp and are only observed in K. oxytoca strains. MTT assay was used to evaluate cytotoxic activity. In this study, colorimetric method was used to evaluate the cytotoxic effect of cytotoxin-producing isolates on Hep-2 cell line and determines the percentage of surviving cells.

Materials And Methods: In this study, we collected a total of 75 K. oxytoca strains isolate and we detected the production of toxins and their cytotoxic effects on HEp-2 cells. Colorimetric method such as MTT assay was used to evaluate the cytotoxic effect of cytotoxin-producing isolates on Hep-2 cell line and determines the percentage of surviving cells.

Results: Nine isolates had cytotoxic effects on HEp-2 cells. The results of MTT assay showed that the isolated strains were different from the control stain in terms of toxinogenicity and cytotoxic effects on HEp-2 cells at the studied dilutions (1:3, 1:6, 1:12, 1:24, 1:48, and 1:96).

Conclusions: In the current study, Percentage of Hep-2 surviving cells exposed to 1:3, 1:6, 1:12, 1:24, 1:48, and 1:96 supernatant dilutions of cytotoxin-producing Klebsiella oxytoca isolates was different.
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http://dx.doi.org/10.1016/j.micpath.2017.11.003DOI Listing
December 2017

The Activity of Fosfomycin Against Extended-Spectrum Beta-Lactamase-Producing Isolates of Enterobacteriaceae Recovered from Urinary Tract Infections: A Single-Center Study Over a Period of 12 Years.

Microb Drug Resist 2018 Jun 24;24(5):607-612. Epub 2017 Oct 24.

1 Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences , Tehran, Iran .

Despite global efforts to tackle resistance in extended-spectrum beta-lactamase (ESBL)-producing isolates via old antibiotics, there are limited data on the efficacy of fosfomycin-an old oral antibiotic-against Enterobacteriaceae in the Middle East. The purpose of this study was to evaluate the in vitro activity of fosfomycin against urinary ESBL-producing isolates of Enterobacteriaceae. Between 2004 and 2015, 363 isolates of ESBL-producing Enterobacteriaceae were recovered from high-risk patients suffering from cardiac disorders and were subjected to polymerase chain reaction using specific primers for the bla, bla, and bla genes. Antibiotic susceptibility testing was performed for fosfomycin and other antibiotic comparators. For the isolates considered nonsusceptible to fosfomycin by disk diffusion, the minimum inhibitory concentration (MIC) was determined. The susceptibility rate to fosfomycin remained almost steady (90-100%) over a 12-year period, although it fluctuated vis-à-vis ciprofloxacin (0-54%), trimethoprim/sulfamethoxazole (9.1-31.7%), and nitrofurantoin (41.7-100%). Of all the antibiotics tested, fosfomycin was the most active antimicrobial agent (97%) against the ESBL-positive isolates. Fosfomycin maintained higher activity against ESBL-Escherichia coli than against ESBL-Klebsiella pneumoniae. Only 11 (3%) isolates were not susceptible to fosfomycin according to disk diffusion and they had MICs greater than 1,024 mg/ml. All of the fosfomycin-nonsusceptible isolates were positive for the bla gene (100%), while 5 (45.4%) and 3 (27.3%) of the isolates harbored the bla and bla genes, respectively. We showed that fosfomycin had a numerically higher susceptibility rate than the other antibiotics against the ESBL-producing isolates of the most common Enterobacteriaceae. Given its low resistance rate and oral administration, fosfomycin may be deemed a promising antibiotic for the treatment of urinary tract infections caused by ESBL-producing Enterobacteriaceae.
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http://dx.doi.org/10.1089/mdr.2017.0097DOI Listing
June 2018

Antimicrobial resistance, virulence genes and genetic relatedness of Salmonella enterica serotype Enteritidis isolates recovered from human gastroenteritis in Tehran, Iran.

J Glob Antimicrob Resist 2018 03 16;12:220-226. Epub 2017 Oct 16.

Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.

Objectives: Salmonella enterica serotype Enteritidis is a major serotype associated with human salmonellosis. The main objective of this study was to determine the antibiotic susceptibility patterns and the presence of virulence-associated genes among S. Enteritidis strains isolated from patients with gastroenteritis in Tehran, Iran.

Methods: Over a period of 14 months (May 2015 to July 2016), 44 S. Enteritidis isolates recovered from clinical sources were characterised for antimicrobial susceptibility and virulence genes. Possible genetic relatedness among the strains was also assessed using pulsed-field gel electrophoresis (PFGE).

Results: Salmonella Enteritidis isolates showed high rates of resistance to ciprofloxacin (90.9%) and nalidixic acid (77.3%). Of the 44 S. Enteritidis isolates, 30 (68.2%) were resistant to three or more antibiotics. Twenty-two different antimicrobial resistance patterns were detected among the isolates. The most frequent resistance type was antibiotype 14 (resistance to ciprofloxacin, cefuroxime and nalidixic acid), occurring in 8 (18.2%) of the isolates. Notably, all of the isolates carried invA, sefA, sipA and sopE2 virulence genes. Furthermore, 17 virulence profiles were observed among the strains. The most common virulence profile was VP1 (n=17; 38.6%), harbouring all of the virulence genes. Two distinct PFGE patterns were observed among 44S. Enteritidis isolates. There was no association between virulence profiles or antibiotypes and PFGE clusters.

Conclusions: Overall, this study provides valuable information on the virulence gene content, antibiotic resistance and genetic diversity of S. Enteritidis isolated from human sources in Iran.
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http://dx.doi.org/10.1016/j.jgar.2017.10.005DOI Listing
March 2018

Characterization of the DNA mismatch repair proteins MutS and MutL in a hypermutator Acinetobacter baumannii.

Microb Pathog 2017 Dec 5;113:74-84. Epub 2017 Oct 5.

Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

Mutations of mutS and mutL genes have been linked with the emergence of hypermutator (HPM) phenotype in several bacteria. Nevertheless, there is scarce evidence that these mutations occurred in HPM Acinetobacter baumannii, therefore, it remains unknown whether the mutations located in domains mediating the functions of MutS and MutL. To address this information gap, the nucleotide sequences of mutS and mutL were characterized and their mutations were identified. Additionally, we proposed in silico models of mutated proteins and analyzed the secondary and tertiary structures, and the interaction interfaces of MutL and MutS. The HPM A. baumannii and a wild-type strain were subjected to PCR amplification of full length mutS and mutL, cloning, and sequencing. Following several reads of both strands of each gene and sequence assembly, the mutations were identified. Thereafter, the three-dimensional (3-D) structure of A. baumannii ATCC 19606 was developed and utilized as a template for homology modeling of the mutated amino acid sequences using the Phyre and I-TASSER, VMD 1.9.3, LigPlus v.1.4.5, PyMOL v.0.99 software. Regardless of silent mutations (n = 43), 11 missense mutations were identified in the MutS domains of HPM strain such as A4T, T272S, D278N in N-terminus, connector, and core domains, respectively. Three mutations -I357T, A408S, N447S- and 16 silent mutations were observed in MutL. Secondary structure prediction of MutS revealed that the amount of alpha helices, beta sheets, and coils in HPM were 35, 29, and 63, respectively, while these values were 36, 28, and 63 for A. baumannii ATCC 19606 as non mutator. In the case of MutL, for both HPM and non-mutator, 20, 21, and 39 of complete protein were alpha helices, beta sheets, and coils, respectively. Superimposition of structures of MutS of HPM on non-mutator revealed that T272, D278, G457, S528, A533, Y715, and E747 are closely matched with S272, D278, A457, P528, V533, C715, and K747, respectively in non-mutator strain. When the structure of MutL model in HPM was superimposed on its counterpart in non-mutator, all but residues S447, S408, and T357 were identical. Many mutations along the mutS and mutL were noted, but most of the mutations were observed in the interaction interfaces of MutS and MutL. Other substitutions were predominantly detected in C-terminus of MutS that may lead to reduced ATP binding and hydrolysis. Three substitution mutations were adjacent to C-terminus of MutL and are raising the suggestion of reduction in MutL dimerization. It seems that a combination of these mutations is implicated in increased mutation frequency and accordingly emergence of HPM strain.
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http://dx.doi.org/10.1016/j.micpath.2017.10.001DOI Listing
December 2017

Identification of cytotoxin-producing Klebsiella oxytoca strains isolated from clinical samples with cell culture assays.

Microb Pathog 2017 Dec 29;113:1-4. Epub 2017 Sep 29.

Noor Pathobiology Laboratory, Tehran, Iran.

Background: Klebsiella oxytoca is an opportunistic pathogen which damages intestinal epithelium through producing cytotoxin tilivalline. This toxin plays a role in the pathogenesis of bacteria and is the main virulence factor which leads to antibiotic-associated hemorrhagic colitis progress.

Materials And Methods: In this study, we collected a total of 75 K. oxytoca strains isolated from the stool, urine, blood, wounds, and sputum and evaluated them in terms of the production of toxins; we detected their cytotoxic effects on HEp-2 cells.

Results: Of all the isolates, five K. oxytoca strains isolated from the stool cultures, two strains isolated from the blood cultures, one strains isolated from the wound cultures, and one strains isolated from the urine cultures had cytotoxic effects on HEp-2 cells. The strains isolated from sputum cultures had no cytotoxic effects on HEp-2 cells.

Conclusions: In the current study, the majority of strains isolated from the stool of the patients included cytopathic effects on HEp-2 cells.
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http://dx.doi.org/10.1016/j.micpath.2017.09.063DOI Listing
December 2017

High prevalence of diverse vancomycin resistance Enterococcus faecium isolates in clinical and environmental sources in ICU wards in southwest of Iran.

Microb Pathog 2017 Oct 4;111:212-217. Epub 2017 Sep 4.

Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Electronic address:

This study aimed at determining the prevalence, antibiotic resistance patterns, and genetic linkage of Vancomycin Resistant Enterococcus faecium (VREfm) from different sources in the southwest of Iran. A total of 51 VREfm isolates were obtained and subjected to antibiotic susceptibility testing, carriage of virulence genes, and pulsed-field gel electrophoresis (PFGE) method. All the VRE isolates exhibited a high level of resistance to teicoplanin, ampicillin, erythromycin, ciprofloxacin, and gentamicin, also carried the vanA gene. A total of 59% and 34% of the VREfm strains harbored esp and hyl genes, respectively. The results from PFGE showed 31 PFGE patterns including 10 common types (CT) and 21 single types (ST) among the VRE isolates. Furthermore, isolates from different sources in each common type revealed cross transmission between clinical and environmental sources. Overall, the study showed a high prevalence of diverse VRE faecium strains with threatening resistance phenotypes in the environment and clinical sections among different ICU wards of Ahvaz hospitals.
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http://dx.doi.org/10.1016/j.micpath.2017.08.045DOI Listing
October 2017

Bifidobacterium obtained from mother's milk and their infant stool; A comparative genotyping and antibacterial analysis.

Microb Pathog 2017 Oct 18;111:94-98. Epub 2017 Aug 18.

Department of Microbiology, Pasteur Institute of Iran, Tehran, Iran. Electronic address:

Antibacterial activity of Bifidobacterium species has been considered as an important probiotic property for development of human gut immunity. This study was conducted to assess the genotypes and antibacterial activities of the native Bifidobacterium isolates obtained from the human's breast milk and the feces of their paired infants. Fifty-six samples from twenty-eight mothers' milk and paired infants feces were collected and cultured. Suspicious colonies were picked up and confirmed by phenotypic and molecular identifications. Randomly amplified polymorphic DNA (RAPD-PCR) and antibacterial activity were carried out. Amongst 56 samples, 41 different Bifidobacterium species including 12 B. breve, 14 B. longum, and 15 B. bifidum were isolated. Out of which, 12 isolates including B. longum (6), B. breve (4) and B. bifidum (2) were shared between six mother-infant pairs. Only three strains of B. longum showed 100% similarity in their RAPD-PCR. No significant difference was observed in the antibacterial activity of the Bifidobacterium isolates, with the same or different RAPD-PCR profile, against the enteric bacteria. Overall, 29% of the Bifidobacteria species isolated from the mothers milk and their paired infants feces were shared. All species of Bifidobacteria showed the universal role of antipathogens activities irrespective of the host and the isolation site.
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http://dx.doi.org/10.1016/j.micpath.2017.08.014DOI Listing
October 2017

Variable spontaneous mutation rate in clinical strains of multidrug-resistant Acinetobacter baumannii and differentially expressed proteins in a hypermutator strain.

Mutat Res 2017 08 8;800-802:37-45. Epub 2017 Jun 8.

Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Background: The emergence of multidrug resistant Acinetobacter baumannii within hospitals poses a significant threat to patients. The inherent rate of mutation of these strains has not been described nor has the mechanism by which drug resistance arises.

Methods: Here, we determined the spontaneous mutation rates in 93 clinical strains of A. baumannii using fluctuation analysis. To rule out the clonal relatedness of hypermutator strains, pulsed-field gel electrophoresis (PFGE) was conducted. Using a combination of two-dimensional gel electrophoresis (2-DE) and MALDI-TOF mass spectrometry, the differentially expressed proteins of a hypermutator and a reference strain were identified.

Results: The spontaneous mutation rate of multi-drug resistant A. baumannii strains varied broadly from 0 to 2.1×10 mutation per cell division. The mutation rate in three multidrug resistant A. baumannii (MDR-AB) strains was found to be 1.63×10 (95% confidence interval (CI): 1×10-2×10), 2.1×10 (95% CI: 2×10 - 3×10), and 1.78×10 (95% CI: 9.29×10 2.95×10), consistent with a hypermutator phenotype. This rate is approximately 1000-fold higher than the average mutation rate in other MDR-ABs. PFGE of the three hypermutator strains indicate that they belong to distinct clones. Proteomic analysis of one hypermutator strain revealed 31 differentially expressed proteins including three with sizes of 51.2, 20.9, and 11.9kDa, which corresponded to a serine protease, a polyisoprenoid-binding protein, and the peptidoglycan binding protein, LysM. The serine protease was expressed only in the hypermutator strain, whereas the polyisoprenoid-binding protein and the peptidoglycan binding protein LysM were down-regulated 1.6 and 3-fold, respectively, in the hypermutators strain.

Conclusion: Hypermutator A. baumannii strains occur with a low, but appreciable frequency among clinical multi-drug resistant isolates. The presence of hypermutator clinical isolates raises concerns that they may contribute to the failure of antibiotic treatment in infected patients and confound the interpretation of in vitro antibiotic susceptibility testing. The differentially expressed proteins involved in biofilm suppression and oxidative stress response, may represent adaptations derived from the hypermutator phenotype, a hypothesis that needs further testing.
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http://dx.doi.org/10.1016/j.mrfmmm.2017.06.002DOI Listing
August 2017