Evaluating CD4 and Foxp3 mRNA Expression in Tissue Specimens of Celiac Disease and Colorectal Cancer Patients.

OBJECTIVE: Celiac disease (CD) and colorectal cancer (CRC) are distinct gastrointestinal conditions with a debated association. This study aimed to evaluate the mRNA expression of CD4 and Foxp3 in tissue specimens of CD and CRC patients. The findings can provide valuable insights into the complex connection between these different gastrointestinal conditions. METHODS: Tissue samples from 100 CRC patients, 50 CD patients, and 50 healthy controls (HCs) were collected. RNA extraction, cDNA synthesis, and quantitative real-time PCR were performed. Statistical analysis was conducted using ANOVA and Pearson's correlation test. RESULT: CD4 mRNA expression was significantly higher in CRC patients compared to CD patients and HCs (P<0.0001 for both). Foxp3 mRNA expression was significantly higher in CD patients compared to CRC patients and HCs (P<0.0001 for both). Clinicopathological characteristics did not correlate significantly with gene expression levels. CONCLUSION: This study reveals differential expression patterns of CD4 and Foxp3 mRNA in CRC and CD patients. Upregulated CD4 mRNA suggests its potential role in promoting tumor growth, while increased Foxp3 mRNA expression may reflect an immunosuppressive mechanism in CD pathogenesis. These findings provide insights into the molecular and immunological aspects of CRC and CD, warranting further studies for potential therapeutic strategies.

Biliary co-infection by multidrug-resistant Candida glabrata and Candida albicans in a case of pancreatic cancer with cholangitis: A case report and review of literature.

Herein, we report a case of pancreatic cancer with acute cholangitis secondary to biliary obstruction. Empirical antibiotic therapy did not change the clinical presentation. Blood cultures were sterile; however, bile culture was positive for yeasts. Our laboratory analysis revealed a biliary coinfection by multidrug-resistant C. glabrata and C. albicans. The patient was successfully treated with endoscopic biliary drainage.

High prevalence of Mucosa-Associated extended-spectrum ß-Lactamase-producing Escherichia coli and Klebsiella pneumoniae among Iranain patients with inflammatory bowel disease (IBD).

BACKGROUND: Several pieces of evidence suggest that certain pathobionts belonging to Enterobacterales are associated with the development and progression of inflammatory bowel diseases (IBD). Extended-spectrum ß-lactamases (ESBLs) ESBLs are frequently found in the Enterobacterales members, particularly in Escherichia coli and Klebsiella spp., and might trigger antibiotic-induced perturbations of the intestinal microbiota and led to more severe disease activity in IBD. Therefore, the severity of IBD could be influenced by ESBL-producing Enterobacterales, and hence, this study aimed to investigate the presence of ESBLs and carbapenemases among mucosa-associated E. coli and Klebsiella pneumoniae isolated from colonic biopsies of Iranian patients with IBD. METHODS: In this cross-sectional study, E. coli and K. pneumoniae were isolated from inflamed ileum and/or colon tissue of patients with IBD, including Ulcerative colitis (UC) and Crohn's disease (CD), during colonoscopy. Demographic data and clinical characteristics were recorded, and UC and CD disease activity and extent were evaluated according to the full Mayo score and Crohn's disease activity index (CDAI), respectively. Phenotypic and molecular detection of ESBL- and carbapenemase-producing E. coli and Klebsiella pneumoniae were carried out. Disease activity and other clinical and microbial features were compared in patients with and without gut colonization with ESBL producers. RESULTS: A total of 83 IBD patients, including 67 UC and 16 CD, were enrolled in the initial analysis. Intestinal colonization with ESBL-producing E. coli and/or Klebsiella pneumoniae was found in 37 (55.2%) of UC and 9 (56.2%) of DC patients - mostly harbored E. coli containing the blaCTX-M and blaTEM genes. UC patients with intestinal colonization with ESBL-producers had more severe disease compared with patients without colonization. Moreover, 10.2% of tested E. coli and 34.8% of K. pneumoniea were recognized as potential carbapenemase producers. CONCLUSION: Intestinal colonization with ESBL producers could arise disease activity in IBD patients. Further large-scale case-control studies should be performed to investigate the possible confounding factors that could contribute to this outcome.

Genetic diversity of Helicobacter pylori type IV secretion system cagI and cagN genes and their association with clinical diseases.

A number of cagPAI genes in the Helicobacter pylori genome are considered the most evolved genes under a diversifying selection and evolutionary pressure. Among them, cagI and cagN are described as a part of the two different-operon of cagPAI that are involved in the T4SS machinery, but the definite association of these factors with clinical manifestations is still unclear. A total of 70 H. pylori isolates were obtained from different gastroduodenal patients. All isolates were examined for the presence of primary H. pylori virulence genes by PCR analysis. Direct DNA sequence analysis was performed for the cagI and cagN genes. The results were compared with the reference strain. The cagI, cagN, cagA, cagL, vacA s1m1, vacA s1m2, vacA s2m2, babA2, sabA, and dupA genotypes were detected in 80, 91.4, 84, 91.4, 32.8, 42.8, 24.4, 97.1, 84.3, and 84.3% of the total isolates, respectively. The most variable codon usage in cagI was observed at residues 20-25, 55-60, 94, 181-199, 213-221, 241-268, and 319-320, while the most variable codon usage in CagN hypervariable motif (CagNHM) was observed at residues 53 to 63. Sequencing data analysis of cagN revealed a hypothetical hexapeptide motif (EAKDEN/K) in residues of 278-283 among six H. pylori isolates, which needs further studies to evaluate its putative function. The present study demonstrated a high prevalence of cagI and cagN genes among Iranian H. pylori isolates with gastroduodenal diseases. Furthermore, no significant correlation between cagI and cagN variants and clinical diseases was observed in the present study. However, all patients had a high prevalence of cagPAI genes including cagI, cagN, cagA, and cagL, which indicates more potential role of these genes in disease outcome.

Systematic Review and Dose-Response Meta-Analysis on the Relationship between Different Gluten Doses and Risk of Coeliac Disease Relapse.

Gluten proteins are known as immunological triggers for inflammation resulting in mucosal lesions in patients with coeliac disease (CD). Adherence to a strict gluten-free diet (GFD) is currently known as the only effective treatment for CD. In this study, we performed a systematic review and dose-response meta-analysis on data from previous studies to investigate the association between different gluten doses administered and the risk of CD relapse. Electronic databases were systematically searched to retrieve studies that investigated the response of CD patients to different amounts of gluten intake and evaluated the clinical, serologic, and/or histologic evidence to recognize disease relapse. Study-specific relative risks (RRs) were combined using a random effects model. A total of 440 identified published papers were screened, of which 7 records were selected following full-text reviewing and eligibility assessment for dose-response meta-analysis. According to our analysis, the risk of CD relapse is estimated to be 0.2% (RR: 1.002; 95% CI: 1.001 to 1.004) following the consumption of 6 mg gluten/day, which was increased to 7% (RR: 1.07; 95% CI: 1.03 to 1.10), 50% (RR: 1.50; 95% CI: 1.23 to 1.82), 80% (RR: 1.80; 95% CI: 1.36 to 2.38), and 100% (RR: 2.00; 95% CI: 1.43 to 2.78) by the daily intake of 150, 881, 1276, and 1505 mg gluten, respectively. Although good adherence to a GFD can adequately control CD-related symptoms, disease relapse might happen even with a very low dose of gluten, and the duration of exposure to gluten is also an important matter. The current literature has substantial limitations, such as relying on the data from just a few countries that were different in terms of the amount of gluten administered, the duration of the challenge, etc. Therefore, more randomized clinical trials using a standardized gluten challenge protocol are needed to confirm the findings of the present study.

Overrepresentation of Enterobacteriaceae and Escherichia coli is the major gut microbiome signature in Crohn's disease and ulcerative colitis; a comprehensive metagenomic analysis of IBDMDB datasets.

Objectives: A number of converging strands of research suggest that the intestinal Enterobacteriaceae plays a crucial role in the development and progression of inflammatory bowel disease (IBD), however, the changes in the abundance of Enterobacteriaceae species and their related metabolic pathways in Crohn's disease (CD) and ulcerative colitis (UC) compared to healthy people are not fully explained by comprehensive comparative metagenomics analysis. In the current study, we investigated the alternations of the Enterobacterales population in the gut microbiome of patients with CD and UC compared to healthy subjects. Methods: Metagenomic datasets were selected from the Integrative Human Microbiome Project (HMP2) through the Inflammatory Bowel Disease Multi'omics Database (IBDMDB). We performed metagenome-wide association studies on fecal samples from 191 CD patients, 132 UC patients, and 125 healthy controls (HCs). We used the metagenomics dataset to study bacterial community structure, relative abundance, differentially abundant bacteria, functional analysis, and Enterobacteriaceae-related biosynthetic pathways. Results: Compared to the gut microbiome of HCs, six Enterobacteriaceae species were significantly elevated in both CD and UC patients, including Escherichia coli, Klebsiella variicola, Klebsiella quasipneumoniae, Klebsiella pneumoniae, Proteus mirabilis, Citrobacter freundii, and Citrobacter youngae, while Klebsiella oxytoca, Morganella morganii, and Citrobacter amalonaticus were uniquely differentially abundant and enriched in the CD cohort. Four species were uniquely differentially abundant and enriched in the UC cohort, including Citrobacter portucalensis, Citrobacter pasteurii, Citrobacter werkmanii, and Proteus hauseri. Our analysis also showed a dramatically increased abundance of E. coli in their intestinal bacterial community. Biosynthetic pathways of aerobactin siderophore, LPS, enterobacterial common antigen, nitrogen metabolism, and sulfur relay systems encoded by E. coli were significantly elevated in the CD samples compared to the HCs. Menaquinol biosynthetic pathways were associated with UC that belonged to K. pneumoniae strains. Conclusions: In conclusion, compared with healthy people, the taxonomic and functional composition of intestinal bacteria in CD and UC patients was significantly shifted to Enterobacteriaceae species, mainly E. coli and Klebsiella species.

Phylogrouping and characterization of Escherichia coli isolated from colonic biopsies and fecal samples of patients with flare of inflammatory bowel disease in Iran.

Background: Although the etiopathogenesis of inflammatory bowel disease (IBD) is still poorly understood, Escherichia coli has been described as a potential causative microorganism in IBD pathogenesis and also disease progression, offering a potential therapeutic target for disease management. Therefore, we conducted this study to investigate the pathotypes, phylogenetic groups, and antimicrobial resistance of E. coli isolates from patients with IBD in Iran. Methods: Fecal and biopsy colonic samples were collected from IBD patients experiencing flare-up episodes referred to Taleghani hospital in Tehran, Iran, between August 2020 and January 2021. Identification of E. coli strains was performed based on biochemical and molecular methods. Antibiotic susceptibility testing was performed as recommended by the Clinical and Laboratory Standards Institute. Phylogrouping and pathotyping of each isolate were carried out using polymerase chain reaction (PCR) and multilocus sequence typing (MLST) assays. Results: A total of 132 non-duplicate E. coli strains were isolated from 113 IBD patients, including 96 ulcerative colitis (UC), and 17 Crohn's disease (CD) patients. In our study, 55% of CD-related E. coli and 70.5% of UC-related isolates were non-susceptible to at least three or more unique antimicrobial classes, and were considered as multidrug-resistant (MDR) strains. E. coli strains exhibited a high level of resistance to cefazolin, ampicillin, tetracycline, ceftazidime, ciprofloxacin, and cefotaxime. Enterotoxigenic E. coli (ETEC) and diffusely adherent E. coli (DAEC) were the most prevalent pathotypes, and groups B2 and D were the predominant phylogroups. Conclusion: In the present study, we found that E. coli strains that colonize the gut of Iranian patients with IBD most frequently belonged to phylogenetic groups B2 and D. We also conclude that E. coli isolates from IBD patients have been revealed to be resistant to commonly used antibiotics, in which most of them harbored strains that would be categorized as MDR.

High Prevalence Rate of Microbial Contamination in Patient-Ready Gastrointestinal Endoscopes in Tehran, Iran: an Alarming Sign for the Occurrence of Severe Outbreaks.

An alarmingly increasing number of outbreaks caused by contaminated gastrointestinal (GI) endoscopes are being reported as a particularly concerning issue. This study is the first large-scale multicenter survey to evaluate the contamination of GI endoscopes in Tehran, Iran. This multicenter study was conducted among 15 tertiary referral and specialized gastrointestinal settings. Reprocessed GI endoscopes were sampled by the sequence of the flush-brush-flush method. Bacterial and viral contamination, as well as antimicrobial resistance, were explored by culture and molecular assays. A total of 133 reprocessed and ready-to-use GI endoscopes were investigated. In phase I and phase II, 47% and 32%, respectively, of the GI endoscopes were determined to be contaminated. GI flora was the most prevalent contaminant isolated from GI endoscopes, in which the most predominant bacteria were Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, in both phase I and II evaluations. The majority of the isolated bacteria in the current study were considered multidrug-resistant organisms (MDROs). More importantly, we recovered carbapenem-resistant nonfermentative Gram-negative bacilli (CRNFGNB), carbapenem-resistant Enterobacterales (CRE), extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales (ESBL-E), multidrug-resistant Clostridioides difficile, vancomycin-resistant Enterococcus (VRE), and drug-resistant Candida spp. Disconcertingly, our molecular assays revealed contamination of some reprocessed GI endoscopes with hepatitis B virus (HBV), hepatitis C virus (HCV), and even HIV. This multicenter study indicates a higher-than-expected contamination rate among reprocessed and ready-for-patient-use GI endoscopes, which suggests a higher-than-expected endoscopy-associated infection (EAI) risk, and potentially, morbidity and mortality rate, associated with endoscopy procedures in Tehran, Iran. IMPORTANCE In the light of severe outbreaks caused by multidrug-resistant microorganisms due to contaminated GI endoscopes, understanding to what extent GI endoscopes are inadequately reprocessed is crucial. Several studies assessed contamination of GI endoscopes with various outcomes across the world; however, the prevalence and risk factors of contaminated GI endoscopes and potential subsequent nosocomial spread are still unknown in Iran. The present study is the first large-scale multicenter survey to evaluate the microbial contamination of repossessed and ready-to-use GI endoscopes in Tehran, Iran. Our study showed a higher-than-expected contamination rate among reprocessed GI endoscopes, which suggests potential seeding of deadly but preventable outbreaks associated with endoscopy procedures in Iran. These results suggest that the current reprocessing and process control guidelines do not suffice in Iran. The current study is of particular importance and could provide insights into unrecognized and unidentified endoscopy-associated outbreaks in Iran.

Investigation and characterization of human gut phageome in advanced liver cirrhosis of defined etiologies.

BACKGROUND: Liver cirrhosis is a major public health problem, accounting for high rates of morbidity and mortality worldwide. The cirrhosis etiology is a broad and essential step in planning a treatment strategy. Many recent studies have documented that gut microbiome alterations play a vital role in the development and progression of cirrhosis and its complications. Nevertheless, there is insufficient data on the correlation between liver cirrhosis and gut phageome alterations in patients with advanced liver diseases. This study aimed to analyze the taxonomic structure and functional attributes of the gut phageome in six different etiologies of advanced liver cirrhosis. METHODS: We first retrieved metagenomic sequencing data from three datasets of fecal samples taken from cirrhotic patients with various etiologies. Subsequently, several bioinformatics pipelines were used to analyze bacteriophage composition and determine their functionality. RESULTS: A gene catalog of 479,425 non-redundant genes was developed as a reference to measure gene prevalence. The results of the analysis revealed a few significant differences among the cohorts at the phage species level. However, the alternations were more evident as there were more in-depth analyses of the functional resolution of the gut phageome. CONCLUSIONS: Our findings suggest that the functional analysis of the gut phageome would provide meaningful markers to predict the progression of liver cirrhosis and facilitate the development of novel treatment approaches.

Investigation of etiology-specific alterations in the gut microbiota in liver cirrhosis.

BACKGROUND: Liver cirrhosis can develop as a consequence of many chronic liver diseases, such as viral hepatitis, fatty liver, or alcohol abuse. There are insufficient data on whether the different etiologies of liver cirrhosis could be related to the specific gut microbial alterations. This study aimed to compare the diversity and composition of the gut microbiota in different etiologies of liver cirrhosis. METHODS: In the current study, the authors used three previously reported metagenomic datasets to investigate the fecal microbiota in cirrhotic patients with distinct etiologies. Microbial diversity and bacterial taxonomic composition were investigated bioinformatically in cirrhotic patients with different etiologies. RESULTS: The analysis revealed no evidence of a significant difference in microbial diversity between cirrhotic patients with different etiologies. At the family level, cirrhotic patients with nonalcoholic fatty liver disease (NAFLD) showed a significantly higher abundance of the Enterobacteriaceae family and the related genera. CONCLUSION: No robust microbial signal was found to differentiate between various underlying etiologies in cirrhotic patients. The data indicate that the geographical origin of cirrhotic patients could affect the composition of the gut microbiome, the effect of which obscures the impact of the etiology of cirrhosis.

Serum procalcitonin levels associate with Clostridioides difficile infection in patients with inflammatory bowel disease.

BACKGROUND: Clostridioides difficile infection (CDI) is a major cause of morbidity among patients with inflammatory bowel disease (IBD). Diagnostic biomarkers for early detection of CDI are needed in clinical practice. The relationship between serum procalcitonin and CDI in IBD patients has not been investigated so far. Therefore, we aimed to evaluate the usefulness of measuring serum procalcitonin level to detect CDI in patients with the flare of IBD. METHODS: One hundred twenty patients with IBD were enrolled in this study. Bacterial identification was performed using standard microbiological and molecular methods. The serum procalcitonin levels were measured in all patients. Receiver operating characteristic (ROC) curve analysis was applied to assess the value of procalcitonin for the prediction of CDI among IBD patients. RESULTS: The median serum procalcitonin level was significantly increased in IBD patients with CDI compared to non-CDI IBD patients (0.69 ng/mL vs 0.32 ng/mL). In univariate analysis, log10 procalcitonin was associated with CDI (OR 2.81, 95% CI 1.54-4.09, P-value < 0.001). Procalcitonin 1.1 ng/mL was 85% sensitive and 88% specific for the prediction of CDI. In the multivariable model including the covariates log10 procalcitonin, age, hospitalization, type of IBD, duration of the disease, and antibiotic usage, procalcitonin showed a robust association with CDI (OR 4.59, 95% CI 2.49-6.70, P-value < 0.001). An elevated procalcitonin level was associated with the presence of CDI among IBD patients. CONCLUSIONS: Our results indicate that procalcitonin level can be a good candidate biomarker for assessing the CDI in IBD patients. Further studies are required to decipher whether procalcitonin can predict CDI therapy or its recurrence.

Influence of low FODMAP-gluten free diet on gut microbiota alterations and symptom severity in Iranian patients with irritable bowel syndrome.

BACKGROUND AND OBJECTIVE: Recently, dietary restriction of fermentable carbohydrates (a low-FODMAP diet) in combination with a gluten-free diet (GFD) has been proposed to reduce the symptoms in irritable bowel syndrome (IBS) patients. Different studies reported that IBS has been associated with dysbiosis in the gut microbiota. Additionally, a few studies have reported inflammation in the gastrointestinal (GI) system of adults with IBS. In this study, we aimed to investigate the effects of low FODMAP-gluten free diet (LF-GFD) on clinical symptoms, intestinal microbiota diversity, and fecal calprotectin (FC) level in Iranian patients with IBS. DESIGN: In this clinical trial study, 42 patients with IBS (Rome IV criteria) underwent LF-GFD intervention for 6 weeks. Symptoms were assessed using the IBS symptom severity scoring (IBS-SSS), and fecal samples were collected at baseline and after intervention and analyzed by quantitative 16 S rRNA PCR assay. The diversity of gut microbiota compared before and after 6 weeks of dietary intervention. FC was also analyzed by the ELISA method. RESULTS: Thirty patients (mean age 37.8 ± 10.7 years) completed the 6-week diet. The IBS-SSS was significantly (P = 0.001) reduced after LF-GFD intervention compared to the baseline. Significant microbial differences before and after intervention were noticed in fecal samples. A significant increase was found in Bacteroidetes, and the Firmicutes to Bacteroidetes (F/B) ratio was significantly (P = 0.001) decreased after the dietary intervention. The value of FC was significantly decreased after 6 weeks of dietary intervention (P = 0.001). CONCLUSIONS: Our study suggests that patients with IBS under an LF-GFD had a significant improvement in IBS symptoms severity, with reduced FC level following normalization of their gut microbiota composition. Further rigorous trials are needed to establish a long-term efficacy and safety of this dietary intervention for personalized nutrition in IBS. Clinical Trial Registry Number: IRCT20100524004010N26.

Characterization of the gut microbiota in patients with primary sclerosing cholangitis compared to inflammatory bowel disease and healthy controls.

BACKGROUND: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease. Its etiology remains largely unknown, although frequent concomitant inflammatory bowel disease (IBD) hints towards common factors underlying intestinal and bile duct inflammation. Herein, we aimed to explore the relative abundance of fecal microbiota in PSC-IBD patients compared to IBD-only subjects and controls. METHODS AND RESULTS: We included 14 PSC-IBD patients, 12 IBD-only patients, and 8 healthy controls (HCs). A quantitative real-time PCR (qPCR) assay was used to determine a selection of bacterial phyla, families, and genera. Relative abundance of taxa showed that Bacteroidetes was the most abundant phylum among the patients with PSC-IBD (29.46%) and also HCs (39.34%), whereas the bacterial species belonging to the phylum Firmicutes were the most frequent group in IBD-only subjects (37.61%). The relative abundance of the Enterobacteriaceae family in fecal samples of PSC-IBD patients was similar to those with IBD-only, which was significantly higher than HCs (p value = 0.031), and thus, could be used as a PSC-IBD or IBD-only associated microbial signature. CONCLUSIONS: Our findings showed that intestinal microbiota composition in PSC-IBD patients was completely different from that of IBD-only patients. Further studies using large-scale cohorts should be performed to better describe the contribution of the gut microbiota to PSC pathogenesis with underlying IBD.

Prevalence of the pathobiont adherent-invasive Escherichia coli and inflammatory bowel disease: a systematic review and meta-analysis.

BACKGROUND AND AIM: Escherichia coli pathobionts and particularly the adherent-invasive E. coli (AIEC) may play a putative role in initiating and maintaining the inflammatory process in the intestinal tissues of inflammatory bowel disease (IBD) patients, by providing stimulatory factors that trigger gut immune system activation. The aim of this study is to conduct a systematic review and meta-analysis to determine the prevalence of AIEC among patients with Crohn's disease (CD) and ulcerative colitis (UC). METHODS: Electronic databases were searched up to February 2020 for relevant publications reporting the prevalence of AIEC in IBD patients. The prevalence rate of AIEC among CD and UC patients, the odds ratio (OR) and 95% confidence interval (CI) were calculated compared to non-IBD controls. RESULTS: The final dataset included 12 studies, all investigating AIEC isolates from ileal/colonic specimens. The OR for prevalence of AIEC in CD patients was 3.27 (95% CI 1.79-5.9) compared with non-IBD controls. The overall pooled prevalence of AIEC among CD patients was 29% (95% CI 0.17-0.45), whereas this prevalence was calculated to be 9% (95% CI 0.03-0.19) in controls. Moreover, the prevalence of AIEC in UC subjects was calculated 12% (95% CI 0.01-0.34), while AIEC showed a prevalence of 5% (95% CI 0.0-0.17) among the controls. The OR for prevalence of AIEC in UC patients was 2.82 (95% CI 1.11-7.14) compared with controls. CONCLUSIONS: There is a substantial increase in the prevalence of AIEC in IBD patients compared with controls. This review supports the growing evidence that AIEC could be involved in both CD and UC pathogenesis.

Characterization of biofilm formation and virulence factors of Staphylococcus aureus isolates from paediatric patients in Tehran, Iran.

OBJECTIVES: Staphylococcus aureus can cause several infections. Its capability to form biofilm has been reported to be a vital property involved in the bacteria's pathogenesis. Various genes contributing to biofilm formation have not yet been completely clarified. This study was designed to evaluate the factors influencing adherence and biofilm formation in S. aureus isolated from paediatric patients. MATERIALS AND METHODS: One hundred and ninety-seven S. aureus isolates were obtained from pediatric patients and confirmed with phenotypic and molecular examinations. Antimicrobial susceptibility testing and biofilm formation were evaluated using standard methods. The genes encoding adhesion and virulence factors were investigated by the PCR method. RESULTS: The most efficient antibiotics against S. aureus isolates were vancomycin and linezolid. Approximately, 54.2% of MSSA and 85.6% of MRSA isolates were biofilm producers according to the microtiter test. Our analysis indicated that MRSA isolates are better able to form biofilm compared with MSSA isolates. All isolates harbored clfA, fnbpA, icaA, icaB, icaC, and icaD, while clfB, fnbB, hlg, and pvl were detected in 99.5%, 42.1%, 97.5%, and 5.6% of isolates, respectively. In addition, a significant difference was found in fnhB gene and biofilm formation. CONCLUSION: Our findings showed a significant correlation between mecA and pvl genes and MRSA and biofilm formation in S. aureus isolates. Additionally, this study indicated the significant role of the fnhB gene as a major marker for S. aureus biofilm formation. Therefore, further experiments are warranted to exactly elucidate the function of the fnhB gene in the formation of biofilm.

High Rates of Antimicrobial Resistance and Virulence Gene Distribution Among Shigella spp. Isolated from Pediatric Patients in Tehran, Iran.

BACKGROUND: Shigella continues to be important causes of acute pediatric diarrhea worldwide. Shigella produces numerous virulence factors involved in colonization and invasion into epithelial cells which eventually result in the disease. The present study was conducted to evaluate the prevalence of virulence genes and to investigate antibiotic resistance profiles among Shigella isolates obtained from pediatric patients in Iran. METHODS: A total of 141 Shigella isolates were collected between March 2017 and September 2018 from stool of children under 14 who were suspected to have shigellosis. Shigella isolates were identified using standard microbiological and serological tests and antimicrobial susceptibility testing was carried out via Kirby-Bauer disk diffusion method. In addition, the presence of seven virulence determinants including ipaH, ipaB, ipaC, ipaD, ipgD, sen, and virA were evaluated using PCR. RESULTS: S. sonnei (78.7%) was the most prevalent shigella spp. among children with shigellosis followed by S. flexneri (19.9%) and S. boydii (1.4%). Antimicrobial susceptibility testing revealed that most of the isolates were considered as multidrug-resistant (MDR) strains. Our findings also showed a high resistance rate against trimethoprim-sulfamethoxazole in Shigella isolates. The prevalence of ipaH, ipaC, sen, ipaD, virA, ipaB, and ipgD were 100%, 95.7%, 95.7%, 94.3%, 93.6%, 92.9%, and 80.8%, respectively. CONCLUSION: The current study revealed that S. sonnei was the predominant species isolated from children with shigellosis in Iran. Our results also indicated a high distribution of type III secretion system effector protein-encoding genes and high multidrug-resistance among shigella spp. in Iran. Therefore, it is suggested that antimicrobial susceptibility testing be performed prior to antibiotic prescription.

Exploiting yoeB-yefM toxin-antitoxin system of Streptococcus pneumoniae on the selective killing of miR-21 overexpressing breast cancer cell line (MCF-7).

Toxin-antitoxin (TA) systems are two-component genetic modules widespread in bacterial and archaeal genomes, in which the toxin module is rendered inactive under resting conditions by its antitoxin counterpart. Under stress conditions, however, the antitoxin is degraded, freeing the toxin to exert its lethal effects. Although not evolved to function in eukaryotes, some studies have established the lethal activity of these bacterial toxins by inducing apoptosis in mammalian cells, an effect that can be neutralized by its cognate antitoxin. Inspired by the way the toxin can become active in eukaryotes cells, we produced an engrained yoeB-yefM TA system to selectively kill human breast cancer cells expressing a high level of miR-21. Accordingly, we generated an engineered yefM antitoxin gene with eight miR-21 target sites placed in its 3'untranslated region. The resulting TA system acts autonomously in human cells, distinguishing those that overexpress miR-21, killed by YoeB, from those that do not, remaining protected by YefM. Thus, we indicated that microRNA-control of the antitoxin protein of bacterial TA systems constitutes a novel strategy to enhance the selective killing of human cancer cells by the toxin module. The present study provides significant insights for developing novel anticancer strategies avoiding off-target effects, a challenge that has been pursued by many investigators over the years.

Early estimation of the epidemiological parameters of novel coronavirus disease (COVID-2019) outbreak in Iran: 19 Feb-15 March, 2020.

AIM: To estimate the epidemiological parameters related to the Covid-19 outbreak in Iran. BACKGROUND: Estimating the epidemiological parameters of new public health threat (COVID-19) is essential to support and inform public health decision-making in different communities including Iran. METHODS: We established a mathematical model to estimate the epidemiological parameters from 19 Feb to 15 March based on daily COVID-19 confirmed cases in Iran. Then, we estimated the effect of early traffic restriction on our estimation. RESULTS: We estimated the R0 at 2.11 (95% CI, 1.87-2.50) and the infected number at 92,260 (95% CI: 59,263 -152,212) by 15 March. Our estimate for the ascertainment rate was about 1.2% (95% CI: 1.1-1.4). The latent period estimation was 4.24 (95% CI: 2.84-6.65). We observed a decline in our estimate after considering the traffic restriction. CONCLUSION: Our results suggest that health authorities in Iran must take impactful strategies to control the COVID-19 outbreak to reach R0<1. Therefore, the establishment of complementary, multilateral, and cost-effective measures for the treatment of symptomatic and early diagnosis and isolation of asymptomatic cases/contacts are strongly recommended because of low ascertainment rate and large number of infected cases. We additionally recommend that traffic restriction be combined with other controlling measures.