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Abstract Background The highly expressed surface antigen 1 (SAG1)-related sequence (SRS) proteins of T. gondii tachyzoites, as a widespread zoonotic parasite, are critical for host cell invasion and represent promising vaccine targets. In this study, we employed a computer-aided multi-method approach for in silico design and evaluation of TgVax452, an epitope-based candidate vaccine against T. gondii tachyzoite-specific SRS proteins. Methods Using immunoinformatics web-based tools, structural modeling, and static/dynamic molecular simulations, we identified and screened B- and T-cell immunodominant epitopes and predicted TgVax452’s antigenicity, stability, safety, adjuvanticity, and physico-chemical properties. Results The designed protein possessed 452 residues, a MW of 44.07 kDa, an alkaline pI (6.7), good stability (33.20), solubility (0.498), and antigenicity (0.9639) with no allergenicity. Comprehensive molecular dynamic (MD) simulation analyses confirmed the stable interaction (average potential energy: 3.3799 × 106 KJ/mol) between the TLR4 agonist residues (RS09 peptide) of the TgVax452 in interaction with human TLR4, potentially activating innate immune responses. Also, a dramatic increase was observed in specific antibodies (IgM and IgG), cytokines (IFN-γ), and lymphocyte responses, based on C-ImmSim outputs. Finally, we optimized TgVax452’s codon adaptation and mRNA secondary structure for efficient expression in E. coli BL21 expression machinery. Conclusion Our findings suggest that TgVax452 is a promising candidate vaccine against T. gondii tachyzoite-specific SRS proteins and requires further experimental studies for its potential use in preclinical trials.

Background: The present systematic review and meta-analysis was done to assess the rate of Toxoplasma gondii (T. gondii) exposure among Iranian healthy blood donors. Methods: We searched four English (PubMed, Scopus, Web of Science, and Science Direct) and two Persian databases (Magiran and SID) as well as Google Scholar as a specialized article search engine using specific keywords for relevant papers from the inception up to November 30, 2023. Results: In total, 19 studies enrolling 8226 apparently healthy blood donors were examined regarding T. gondii-specific IgG and/or IgM antibodies, among which 2666 [32.9% (95% CI: 25.3%–41.6%)], 168 [1.4% (95% CI: 0.9%–2.1%)], and 83 [1.7% (95% CI: 1.3%–2.1%)] subjects were seropositive regarding IgG, IgM, and both IgG/IgM antibodies, respectively. Five risk factors were significantly associated with T. gondii seroprevalence, including gender (OR = 1.98; 95% CI: 1.52–2.58; P

Abstract Cutaneous leishmaniasis (CL) is a very common parasitic infection in subtropical areas worldwide. Throughout decades, there have been challenges in vaccine design and vaccination against CL. The present study introduced novel T-cell-based vaccine candidates containing IFN-γ Inducing epitopic fragments from Leishmania major (L. major) glycoprotein 46 (gp46), cathepsin L-like and B-like proteases, histone H2A, glucose-regulated protein 78 (grp78) and stress-inducible protein 1 (STI-1). For this aim, top-ranked human leukocyte antigen (HLA)-specific, IFN-γ Inducing, antigenic, CD4 + and CD8 + binders were highlighted. Four vaccine candidates were generated using different spacers (AAY, GPGPG, GDGDG) and adjuvants (RS-09 peptide, human IFN-γ, a combination of both, Mycobacterium tuberculosis Resuscitation promoting factor E (RpfE)). Based on the immune simulation profile, those with RS-09 peptide (Leish-App) and RpfE (Leish-Rpf) elicited robust immune responses and their tertiary structure were further refined. Also, molecular docking of the selected vaccine models with the human toll-like receptor 4 showed proper interactions, particularly for Leish-App, for which molecular dynamics simulations showed a stable connection with TLR-4. Upon codon optimization, both models were finally ligated into the pET28a( +) vector. In conclusion, two potent multi-epitope vaccine candidates were designed against CL and evaluated using comprehensive in silico methods, while further wet experiments are, also, recommended.

Toxoplasmosis is a common and serious infection caused by an obligatory intracellular protozoan, Toxoplasma gondii. This study investigated the possible association between heart failure and toxoplasmosis. We searched for toxoplasmosis and heart failure patients in English databases including PubMed, Scopus, ISI Web of Sciences, Science Direct, EMBASE, and Google Scholar up to June 2018. A total of 6 studies and 1,795 participants, comprising 934 cases and 861 controls, had acceptable criteria for entering the study. Im­munoglobulin G (IgG) antibodies against T. gondii were found in 53% (22 to 83) of patients with heart diseases and 26% (11 to 42) of healthy controls. In comparison, immunoglobulin M (IgM) antibodies were found in 0.5% (0.1 to 1) in patients with heart diseases and 0.3% (0 to 0.7) of healthy controls. The patients suffering from cardiac disorders were more significantly correlated to anti-T. gondii IgG (OR: 3.53; 95% CI, 2.27 to 5.47; P = 0.014) and IgM (OR: 1.80; 95% CI, 0.31 to 10.4; P = 0.028) seropositivity than healthy controls. Despite limitations such as the low number of studies, our research showed a high association between toxoplasmosis and cardiac disorders. Therefore, toxoplasmosis may be a risk factor in cardiac patients, and more studies are being done.

Abstract Background Urinary schistosomiasis is a serious threat in endemic territories of Africa and the Middle East. The status of female urinary schistosomiasis (FUS) in published literature between 2016 and 2020 was investigated. Methods A systematic search in PubMed, Scopus, Google Scholar, and Web of Science, based on the ‘Preferred Reporting Items for Systematic Reviews and Meta-analyses’ checklist, and a meta-analysis using random-effects model to calculate the weighted estimates and 95% confidence intervals (95% CIs) were done. Results Totally, 113 datasets reported data on 40,531 women from 21 African countries, showing a pooled prevalence of 17.5% (95% CI: 14.8–20.5%). Most studies (73) were performed in Nigeria, while highest prevalence was detected in Mozambique 58% (95% CI: 56.9–59.1%) (one study). By sample type and symptoms, vaginal lavage [25.0% (95% CI: 11.4–46.1%)] and hematuria 19.4% (95% CI: 12.2–29.4%) showed higher FUS frequency. Studies using direct microscopy diagnosed a 17.1% (95% CI: 14.5–20.1%) prevalence rate, higher than PCR-based studies 15.3% (95% CI: 6.1–33.2%). Except for sample type, all other variables had significant association with the overall prevalence of FUS. Conclusions More studies are needed to evaluate the true epidemiology of FUS throughout endemic regions.

Cryptosporidiosis is a zoonotic parasitic infection causing diarrhea in humans and farm animals. The present study was done to computationally analyze the Cryptosporidium parvum sporozoite glycoprotein antigen (SGA) regarding immunogenic epitopes, as a potential vaccine candidate. Physico-chemical properties, solubility, antigenicity, allergenicity, signal peptide, transmembrane domain and post-translational modifications (PTMs) along with secondary and tertiary structure analyses were predicted. Also, linear B-cell epitopes, cytotoxic T-lymphocyte (CTL; human, cattle) and helper T-lymphocyte (HTL; human) epitopes were forecasted. The molecular weight of this 265-residue protein was 27.14 kDa, with hydrophilicity (GRAVY: 0.700), high solubility (0.892), and aliphatic index (46.83). No signal peptide and transmembrane domain was predicted, and the most abundant PTMs were phosphorylation (n = 68) and O-glycosylation (n = 53). Coils were dominant in secondary structure analysis, and the tertiary model refinement showed enhancement in the refined than crude model. Only 4 shared B-cell epitopes among three web servers (ABCpred, BepiPred 2.0, and SVMTriP) were shown to be antigenic, non-allergenic, with good water solubility. Also, five potent CTL epitopes in humans and two in cattle were predicted. Notably, four HTL epitopes were found as inducers of IFN-γ, IL-4 or both. In conclusion, our results demonstrated several immunogenic epitopes in this protein, which could be directed towards multi-epitope vaccine design.

Background: Toxoplasmosis is a global public health concern with severe complications, particularly in pregnant women and immunosuppressed patients. Herein, we revealed the first genotypic evidence of Toxoplasma gondii (T. gondii) in diabetic and non-diabetic individuals referred to Imam Sajjad Hospital, Tehran, Iran, using nested-Polymerase Chain Reaction (PCR) and sequencing. Materials and Methods: We collected 98, 95, and 94 blood samples from Type-1 Diabetes Mellitus (T1DM), Type-2 Diabetes Mellitus (T2DM), and control subjects from February to August 2018, and their DNA was extracted. After amplification and visualization of dense granule antigen 6 gene (344 bp) using external and internal primer pairs, the positive samples were sent for sequencing. Results: Among 287 individuals, three T1DM patients (two IgG, one IgM) and one T2DM patient (IgG) were found positive by molecular method, which proved to be type III strain by sequencing. Conclusion: To the best of our knowledge, this is the first genotyping investigation on T. gondii in diabetic individuals. Further research should be done to better realize the association between Toxoplasma genotypes and the outcome of diabetes mellitus.

Introduction: Thalassemia is associated with a genetic decline in the rate of synthesis of one or more types of natural hemoglobin polypeptide chains. One of the major complications in thalassemia patients is alloimmunization, which is antibody production by the patient against transfused red blood cells (RBCs). These RBCs are unknown by the recipient and the formed antibodies against them are called alloantibodies. This study aimed to evaluate the frequency of alloantibodies against RBCs in beta-thalassemia patients referred to Tehran Regional Blood Transfusion Center. Methods: In this study, antibody screening tests (Dia-cell I, II, and III) were performed on 184 thalassemia patients. An identification test by the Dia panel consisting of 11 different O RBCs groups to examine sera with Dia cells (I, II, or III) was performed. Results: In our study, males and females patients comprised 66 (35.87%) and 118 (64.13%), respectively, of whom 116 (63%) had alloimmunization. In addition, 68 thalassemia subjects (37%) lacked alloantibodies. Among 184 patients with beta-thalassemia major, anti-K (Kell system), anti-D, and anti-E (Rhesus system) had the most abundant alloantibody variants with an incidence of 24 (13%), 11 (5.98%), and 10 (5.4%), respectively. Conclusion: Before RBC transfusion, regular RBC antigen phenotypes, as well as problem-solving of alloantibody production by receiving compatible blood for Kell and RH subgroups, are suggested for all cases of transfusion-derived thalassemia.

Abstract Objectives Toxoplasma gondii (T. gondii), an obligate intracellular apicomplexan parasite, could affect numerous warm-blooded animals, such as humans. Calcium-dependent protein kinases (CDPKs) are essential Ca2+ signaling mediators and participate in parasite host cell egress, outer membrane motility, invasion, and cell division. Results Several bioinformatics online servers were employed to analyze and predict the important properties of CDPK4 protein. The findings revealed that CDPK4 peptide has 1158 amino acid residues with average molecular weight (MW) of 126.331 KDa. The aliphatic index and GRAVY for this protein were estimated at 66.82 and – 0.650, respectively. The findings revealed that the CDPK4 protein comprised 30.14% and 34.97% alpha-helix, 59.84% and 53.54% random coils, and 10.02% and 11.49% extended strand with SOPMA and GOR4 tools, respectively. Ramachandran plot output showed 87.87%, 8.40%, and 3.73% of amino acid residues in the favored, allowed, and outlier regions, respectively. Also, several potential B and T-cell epitopes were predicted for CDPK4 protein through different bioinformatics tools. Also, antigenicity and allergenicity evaluation demonstrated that this protein has immunogenic and non-allergenic nature. This paper presents a basis for further studies, thereby provides a fundamental basis for the development of an effective vaccine against T. gondii infection.

Abstract Background Toxocariasis is a worldwide zoonotic parasitic disease caused by species of Toxocara and Toxascaris, common in dogs and cats. Herein, a meta-analysis was contrived to assess the prevalence of Toxocara/Toxascaris in carnivore and human hosts in different regions of Iran from April 1969 to June 2019. Methods The available online articles of English (PubMed, Science Direct, Scopus, and Ovid) and Persian (SID, Iran Medex, Magiran, and Iran Doc) databases and also the articles that presented in held parasitology congresses of Iran were involved. Results The weighted prevalence of Toxocara/Toxascaris in dogs (Canis familiaris) and cats (Felis catus) was 24.2% (95% CI: 18.0–31.0%) and 32.6% (95% CI: 22.6–43.4%), respectively. Also, pooled prevalence in jackal (Canis aureus) and red fox (Vulpes vulpes) was 23.3% (95% CI: 7.7–43.2%) and 69.4% (95% CI: 60.3–77.8%), correspondingly. Weighted mean prevalence of human cases with overall 28 records was 9.3% (95% CI: 6.3–13.1%). The weighted prevalence of Toxocara canis, Toxocara cati, and Toxascaris leonina was represented as 13.8% (95% CI: 9.8–18.3%), 28.5% (95% CI: 20–37.7%) and 14.3% (95% CI: 8.1–22.0%), respectively. Conclusion Our meta-analysis results illustrate a considerable prevalence rate of Toxocara/Toxascaris, particularly in cats and dogs of northern parts of Iran. The presence of suitable animal hosts, optimum climate and close contact of humans and animals would have been the reason for higher seroprevalence rates of human cases in our region. Given the significance clinical outcomes of human Toxocara/Toxascaris, necessary measures should be taken.

Cutaneous leishmaniasis (CL) is a prevalent disease in the Old World territories especially in the underdeveloped countries of the Middle East. The present study was aimed at prediction of primary biochemical features of the Leishmania major gp63 as a vaccine candidate and its potent linear B-cell epitopes as well as those epitopes with highest binding capacity to mouse and human MHC molecules. A wide range of servers were employed for prediction of physico-chemical, antigenic and allergenic traits, post-translational modifications (PTM), transmembrane domain and subcellular localization, 2D and 3D structures, tertiary model rehashing and validations. The 63.95 kDa protein was antigenic, non-allergenic, hydrophilic and stable, with improved thermotolerance and 43 PTM sites. The secondary structure encompassed 48.67% random coil, 31.4% alpha helix and 19.93% extended strand. Ramachandran analysis of the refined model showed 98.5% and 100% of residues in favored and allowed regions, respectively. After epitope screening, two linear B-cell epitopes and a number of mouse and human MHC-specific epitopes were predicted, which possessed highest antigenic index. This paper provides insights into the bioinformatics characteristics of the L. major gp63 protein as a promising vaccine candidate.

Toxocariasis is a global public health concern, particularly in children. Serological diagnosis of the infection is routinely applied to detect specific anti-Toxocara antibodies. Current in silico study was contrived to design a multi-epitope protein using a wide array of immunoinformatics web servers for improved serodiagnosis. Top, high-ranked B-cell epitopes as well as IL-4 and IL-10 inducing epitopes were predicted, screened and selected to construct the chimeric protein. Then, prediction of antigenicity, solubility and physico-chemical features, secondary and tertiary structures, 3D model refinement and validations was done using various web servers. Finally, conformational B-cell epitopes were determined for possible protein-antibody interactions. Moreover, the final construct was subjected to disulfide engineering, codon adaptation, in silico cloning as well as molecular docking with human TLR-2 molecule. In conclusion, this multi-epitope construct needs to be evaluated experimentally, in order to be used in commercial serodiagnostic kits.

Vaccination is the only feasible way for appropriate prevention of Neospora caninum infection. The present in silico study was done to evaluate the physico-chemical properties and determine immunogenic epitopes of N. caninum SAG1 protein as a possible vaccine candidate. Web-based tools were used to predict physico-chemical properties, antigenicity, allergenicity, solubility, post-translational modification (PTM) sites, transmembrane domains and signal peptide, secondary and tertiary structures as well as intrinsically disordered regions, followed by identification and screening of potential linear and conformational B-cell epitopes and those peptides having affinity to bind mouse major histocompatibility complex (MHC) and cytotoxic T lymphocyte (CTL). The protein was stable in a test tube, had 319 residues with a molecular weight of 33.07 kDa, representing aliphatic index of 76.68 (thermotolerant) and GRAVY score of 0.031 (hydrophobic). There were 42 PTM sites and an N-terminally-located signal peptide in the sequence. Secondary structure comprised mostly by random coils, followed by strands and helices. Ramachandran plot of the refined model showed 71.7%, 24.9%, 3.0% and 0.4% residues in the favored, additional allowed, generously allowed and disallowed regions, correspondingly. Additionally, various potential B-cell (linear and conformational), CTL and MHC-binding epitopes were predicted for N. caninum SAG1. The findings of the present in silico study are a premise for vaccination strategies against neosporosis.

Apicomplexan parasites, including Toxoplasma gondii (T. gondii), express different types of calcium-dependent protein kinases (CDPKs), which perform a variety of functions, including attacking and exiting the host cells. In the current bioinformatics study, we have used several web servers to predict the basic features and specifications of the CDPK7 protein. The findings showed that CDPK7 protein has 2133 amino acid residues with an average molecular weight (MW) of 219085.79 D. The aliphatic index with 68.78 and grand average of hydropathicity (GRAVY) with -0.331 score were estimated. The outcomes of current research showed that the CDPK7 protein included 502 alpha-helix, 1311 random coils, and 320 extended strands with GOR4 method. Considering the Ramachandran plot, the favored region contains more than 92% of the amino acid residues. In addition, evaluation of antigenicity and allergenicity showed that CDPK7 protein has immunogenic and nonallergenic nature. The present research provides key data for more animal-model study on the CDPK7 protein to design an efficient vaccine against toxoplasmosis in the future.

Cystic echinococcosis (CE) is a near-cosmopolitan public health concern, especially in developing countries. Parasite ova shed via definitive host feces are responsible for livestock and occasionally human infection, leading to hydatid cysts. Immunization using proper antigens is a good immunoprophylactic strategy. This study was aimed to design a multi-epitope vaccine using EgA31 and EgG1Y162 antigens. Top high-ranked B-cell epitopes and major histocompatibility complex (MHC)-binding epitopes were predicted and selected to construct the vaccine model. Then, physico-chemical features, secondary and tertiary structures, refinement and validations were all evaluated using web servers for the multi-epitope vaccine construct. Finally, non-linear B-cell epitopes were determined for vaccine-antibody interactions. Moreover, the vaccine construct was subjected to disulfide engineering, molecular docking with human MHC-I and MHC-II molecules as well as codon adaptation and in silico cloning processes. In conclusion, this multimeric CE vaccine needs experimental and clinical confirmations to be considered as an actually immunogenic vaccine model.

Toxoplasmosis is a neglected parasitic disease with global distribution in warm-blooded vertebrates and high prevalence among different human societies. We contrived a systematic review and meta-analysis on the prevalence of toxoplasmosis in Iran. Following the general methodology recommended for systematic reviews and meta-analysis, four English and three Persian electronic databases were explored up to April 2016. Out of 105,139 examined samples of different hosts, the weighted overall prevalence was 37% (95% CI = 31–43). Due to the significant heterogeneity (I2 = 81.9%) the random-effects model was used. The pool estimated prevalence of toxoplasmosis in human intermediate hosts, animal intermediate hosts, and definitive hosts was 43% (95% CI = 38–47), 26 (95% CI = 17–35) and, 34% (95% CI = 22–46), respectively. Our results represent that regular inspection in food industries, improved screening programs using standard diagnostic assay as well as distinguishing toxoplasmosis condition in other zoonotic hosts are extremely recommended for better disease management in Iran. Keywords: Toxoplasma gondii, Prevalence, Iran, Systematic review, Meta-analysis

Toxocariasis is a zoonotic and widespread infection which manifest as a spectrum of syndromes in humans such as visceral, neural, ocular, covert and asymptomatic. Herein we aimed to design a systematic review and meta-analysis to determine the prevalence of Toxocara spp. eggs in soil depositories in Iran. English (PubMed, Scopus, Google Scholar, Web of Science, Science Direct, EBSCO, and Ovid) and Persian (Scientific Information Database and Magiran) databases were explored. This review resulted in a total of 14 publications meeting the inclusion criteria during January 2000–November 2016. Altogether, 3031 soil samples were examined among which 470 were positive in terms of Toxocara spp. The weighted overall prevalence of Toxocara spp. in soil samples was 16% (95% CI = 11–21%), and Tehran and Qazvin provinces had the highest and lowest prevalence rates, respectively. Meta-regression analysis showed that the correlation between prevalence of Toxocara eggs in soil with sample size (P = 0.45) and year of study (P = 0.42) were not statistically significant. Further studies are highly recommended to enlighten different aspects of toxocariasis in Iran. Keywords: Toxocara, Prevalence, Iran, Systematic review, Meta-analysis

Introduction: The global protozoan parasite, Toxoplasma gondii, infects many warm-blooded animals and humans by employing different transmission routes. There have been some recent studies on the probable relevance of infectious agents and diabetes. Therefore, we conducted a systematic review and meta-analysis to identify the possible association between chronic toxoplasmosis and diabetes mellitus. Methods: This study was conducted following the general methodology recommended for systematic reviews and meta-analysis. Nine English literature databases (Google scholar, PubMed, Scopus, Web of science, Science Direct, Ovid, ProQuest, IngentaConnect, and Wiley Online Library) were searched, up to January 2016. Random effects model was used to determine odds ratios and their 95% confidence intervals. Results: Our review resulted in a total of seven publications meeting the inclusion criteria. Because of significant heterogeneity, we estimated a common OR by a random effects model at 1.10 (95% CI = 0.13–9.57) with p = 0.929 and 2.39 (95% CI = 1.20–4.75) with p = 0.013 for type 1 and type 2 diabetes mellitus, respectively. Conclusion: Despite the limitations such as low number of studies, this meta-analysis suggests chronic toxoplasmosis as a possible risk factor for type 2 DM. However, based on random effects model no statistically significant association was observed between T. gondii and type 1 DM. It is highly recommended for researchers to carry out more accurate studies aiming to better understand this association. Keywords: Toxoplasma gondii, Diabetes mellitus, Systematic review, Meta-analysis

> Introduction: Escherichia coli is one of the important pathogens in human with globalimportance. Because of the necessity for identification and the use of novel antibacterialcompounds against E. coli, in this present study we focused on the antibacterial effects ofsynthesized thiazole, imidazole and tetrahydropyridine derivatives on E. coli.Methods: For evaluation of antibacterial effect, the disk diffusion method was applied to measurethe growth inhibition zone diameter and broth micro-dilution was performed to determine theminimum inhibitory concentration (MIC).Results: Assessing the antibacterial effect showed that only 6d derivative of thiazole hadinhibitory effect on E. coli and the other thiazole, imidazole and tetrahydropyridine derivativeslacked any inhibitory result on this organism. The inhibitory effect of 6d derivative of thiazolewas MIC=125 and growth inhibition zone diameter of 16±0.1.Discussion: The antibacterial effect of thiazole, imidazole and tetrahydropyridine derivativesdiffers from each other and chemical linkages such as oxygen to thiazole ring in 6d derivative,could have reinforced this effect. The next step is determination of the toxicity and therapeuticeffects in the laboratory animals.

OBJECTIVES Toxoplasmosis is a parasitic disease that occurs worldwide, with a wide range of complications in immunocompromised patients. This systematic review and meta-analysis was performed to evaluate the seroprevalence of Toxoplasma gondii among patients undergoing hemodialysis in Iran. METHODS We searched English and Persian databases for studies reporting T. gondii seroprevalence in Iranian hemodialysis patients through December 31, 2017. Inclusion and exclusion criteria were applied. RESULTS A total of 10 studies containing 1,865 participants (1,048 patients and 817 controls) met the eligibility criteria. Immunoglobulin G (IgG) antibodies against T. gondii were found in 58% (95% confidence interval [CI], 46 to 70) of hemodialysis patients and 40% (95% CI, 31 to 50) of healthy controls, while immunoglobulin M (IgM) antibodies were found in 2% (95% CI, 0 to 6) of hemodialysis patients and 0% (95% CI, 0 to 1) of healthy controls. The meta-analysis showed that hemodialysis patients were significantly more likely to be seropositive for IgG (odds ratio [OR], 2.04; 95% CI, 1.54 to 2.70; p

Erratum to: Study of Antibacterial Effect of Novel Thiazole, Imidazole and Tetrahydropyridine Derivatives against Escherichia coli

Background and Objectives: Bacterial resistance to antibiotics has motivated the researchers to evaluate the novel anti-bac- terial compounds such as some thiazole and imidazole derivatives. Thereby, in this work, we investigated the anti-bacterial effects of one new thiazole and two new imidazole derivatives on Bacillus cereus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Proteus mirabilis and Shigella dysenteriae. Materials and Methods: The thiazole and imidazole derivatives were dissolved in DMSO. The disk diffusion method was utilized to measure the growth inhibition zone diameter values, and the broth micro-dilution method was applied to deter- mine the minimum inhibitory concentration (MIC) values. Results: The synthesized imidazole derivatives lacked any inhibitory effect against the tested bacteria. On the other hand, although the synthesized thiazole derivative showed no inhibitory effect against Bacillus cereus, Salmonella typhimurium, and Escherichia coli, it inhibited the growth of Proteus mirabilis, Shigella dysenteriae, and Listeria monocytogenes with the MIC values of 1000, 125, and 1000 µg/ml, respectively, and the growth inhibition zone diameter values of 9.3 ± 0.1, 15.6 ± 0.2, and 8.1 ± 0.0 mm, respectively. Conclusion: The anti-bacterial effect of the synthesized thiazole derivative on Shigella dysenteriae, Proteus mirabilis and Listeria monocytogenes was proven. However, its inhibition effect against Shigella dysenteriae was more than that against the others. Many in-vitro and in-vivo experiments are required to evaluate the effects of this compound on the bacteria and the human body.

Background: Escherichia coli is one of the important pathogens in human with global importance. Because of the necessity for identification and the use of novel antibacterial compounds against E. coli, in this present study we focused on the antibacterial effects of synthesized thiazole, imidazole and tetrahydropyridine derivatives on E. coli. Methods: For evaluation of antibacterial effect, the disk diffusion method was applied to measure the growth inhibition zone diameter and broth micro-dilution was performed to determine the minimum inhibitory concentration (MIC). Results: Assessing the antibacterial effect showed that only 6d derivative of thiazole had inhibitory effect on E. coli and the other thiazole, imidazole and tetrahydropyridine derivatives lacked any inhibitory result on this organism. The inhibitory effect of 6d derivative of thiazole was MIC=125 and growth inhibition zone diameter of 16±0.1. Discussion: The antibacterial effect of thiazole, imidazole and tetrahydropyridine derivatives differs from each other and chemical linkages such as oxygen to thiazole ring in 6d derivative, could have reinforced this effect. The next step is determination of the toxicity and therapeutic effects in the laboratory animals.