Molecular and phenotypic characterization of atypical enteropathogenic Escherichia coli serotypes isolated from children with and without diarrhea

BackgroundWe characterized 36 atypical enteropathogenic Escherichia coli (EPEC) serotypes isolated from children with and without diarrhea in Iran. Because the identification of atypical EPEC based on biochemical features is rather difficult and time consuming, we used a combination of three approaches, including a polymerase chain reaction-based method, culture adherence assay, and the restriction analysis of fliC gene (fliC-restriction fragment length polymorphism), to identify E coli serotypes.MethodsTo distinguish typical and atypical EPEC strains, the presence of EPEC attaching effacing A gene (eaeA) gene and EPEC-attaching factor (EAF) plasmid were analyzed. All E coli strains were identified based on the detection of the eaeA+, bundle-forming pili A gene (bfpA−), EAF− or eaeA−, bfpA+, EAF− profiles and the absence of stx (encoded for shiga toxin) gene as atypical EPEC.ResultsAll strains studied belonged to 5 atypical EPEC serogroups and 15 serotypes based on the virulence profiles. Of 36 atypical EPEC serotypes, 22 (61.2%) and 14 (38.8%) strains isolated from diarrheal and healthy cases, respectively. O142:H48 (19.5%) and O111:H21 (11.1%) serotypes were the most prevalent isolates, followed by serotypes O111: H− and O86:H48 (5.6% each).ConclusionsThe characteristics of the atypical EPEC serotypes from children with diarrhea were significantly different from those without diarrhea. The compilation of data on atypical EPEC strains presented here indicates the importance of a combined approach of conventional and molecular tests to study the virulence and epidemiology of EPEC serotypes in human subjects

Isolation, characterization and tolerance survey of bacterial strains to cadmium in soils receiving Hamadan industrial parks wastewater treatment plant effluent

Background and Aims: Biosorption is a relatively new clean up method used for the removal of heavy metals from the environment. Entry of heavy metals into the environment may result in change in population structure and further alteration of resistance mechanism(s) in exposed microorganisms. The first question inthis study sought to determine the threshold of bacterial resistance to cadmium (Cd). The second question was to identify indigenous bacterial species capable of removing the Cd from the soil and consequently to achieve a more efficient biological treatment for industrial effluents.Materials and Methods: Natural topsoil samples were obtained from three industrial parks in Hamadan, Iran. The concentration of Cd in soil samples was measured and thence the bacterial cultures were prepared. Following the screening process, the minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] were determined in order to find the threshold of bacterial tolerance. Indeed, theadsorption capacity of bacterial strains came down in favor of the identification of resistant bacteria.Results: Respectively, 42, 4 and 4 bacterial strains were identified for cultures having average cadmium concentrations of 0.78, 500 and 750 mg/L. This experiment did also detect that Tcd2 and Tcd4 showed the highest MIC with 1250 mg Cd/L. Moreover, TCd2, belonging to the family of Enterobacteriaceae and Enterobacter genus, demonstrated the maximum cadmium removal efficiency (30.2%).Conclusion: The test was successful as it was able to identify the indigenous cadmium tolerant bacteria with high adsorption capacity. This finding has important implications for developing special biological wastewater treatment such as a biofilter in the cadmium-releasing industries.Key words: Cadmium, Hamadan, Industrial park, Resistant bacteria, Soi

Causative agents and antimicrobial susceptibilities of urinary tract infections in the northwest of Iran

SummaryBackgroundThe empirical therapy of urinary tract infections (UTI) relies on the predictability of the agents causing UTI and knowledge of their antimicrobial susceptibility patterns.MethodsIn a prospective study undertaken over a 14-month period, 5136 samples from patients suspected of having a UTI were analyzed, of which 676 were culture-positive. Isolated bacteria were identified by standard tests, and antibiotic susceptibility was determined by disk diffusion method.ResultsAccording to our results, Escherichia coli was the most common etiological agent of UTI (74.6%), followed by Klebsiella spp (11.7%), Staphylococcus saprophyticus (6.4%), and Pseudomonas aeruginosa (2.2%). Analysis of the frequency of isolated bacteria according to the age of the patients revealed that Klebsiella infections are more prevalent in the older age groups (>10 years) and Pseudomonas infections are more prevalent in children and the elderly (<9 years and >60 years). Results of antimicrobial susceptibility analysis for E. coli, as the most prevalent cause of UTI, to commonly used antibiotics are as follows: amikacin (97.8%), gentamicin (97%), ciprofloxacin (94%), nitrofurantoin (87.1%), nalidixic acid (93.7%), trimethoprim–sulfamethoxazole (48.2%), cephalexin (76%), and ampicillin (6.9%).ConclusionsThe results show that the antimicrobial resistance patterns of the causes of UTI are highly variable and continuous surveillance of trends in resistance patterns of uropathogens is important

Performance Evaluation of Return, Risk and Liquidity of Firms Newly Listed in Tehran Stock Exchange

It is essential to understand the behavior of initial offerings in comparison with other firms in different periods of recession and prosperity of stock market, considering three indicators of performance, i.e. return, risk and liquidity. The focus of this study is performance evaluation of newly listed stocks considering above indicators in different periods of recession and prosperity. For this purpose, 317 active firms which were not consistently inactive for three months or traded by March 20, 2006 were studied. Based on the suggested model, performance of the newly listed stocks was evaluated simultaneously based on three indicators of performance. Then, performance of the newly listed stocks was evaluated individually based on those three indicators. Through MANOVA, performance of the newly listed stocks was evaluated better than other stocks. Keywords: initial public offering, return, risk, liquidity JEL Classifications: G11, G3

Apical sealing ability of mineral trioxide aggregate, intermediate restorative material and calcium enriched mixture cement: A bacterial leakage study

Introduction: This in vitro study compared the apical sealing ability of three common root end filling materials namely mineral trioxide aggregate (MTA), intermediate restorative material (IRM) and calcium-enriched mixture (CEM) cement using a bacterial leakage model. Methods and Materials:The study was conducted on 83 single-rooted human teeth. Tooth crowns were cut and root canals were prepared using the step-back technique. Apical 3 mm of the roots were cut and a three-mm-deep cavity was prepared using an ultrasonic instrument. The samples were divided into three groups (n=25) according to the root-end filling material including MTA, IRM and CEM cement. The roots were inserted into cut-end microtubes. After sterilization with ethylene oxide, microtubes were placed in sterile vials containing 10 mL of Brain Heart Infusion (BHI) broth and incubated at 37°C and 0.1 mL ofEnterococcus faecalis suspension compatible with 0.5 McFarland standard (1.5×108 cell/ ml), which was refreshed daily. This procedure was continued for 70 days. The data were analyzed using the chi-square, Kruskal-Wallis and log rank tests. The level of significance was set at 0.05. Results: No significant difference was found in bacterial microleakage among three groups; MTA showed slightly (but not significantly) less microleakage than IRM and CEM. However, the difference in the mean time of microleakage was significant among the groups (P&lt;0.04) and in MTA samples leakage occurred in a longer time than CEM (P&lt;0.012). Conclusion: The three tested root end filling materials had equal sealing efficacy for preventing bacterial leakage.Keywords: Apical Seal; Bacterial Leakage; Microleakage; Root-End Filling; Seal

Effects of TiO2-Coated Stainless Steel Orthodontic Wires on Streptococcus mutans Bacteria: A Clinical Study

Introduction: The aim of this study was to clinically evaluate Streptococcus mutans adhesion on titanium dioxide-coated stainless steel orthodontic wires to decrease white-spot formation. Methods: In this study, four groups of 17 patients each (n=68) aged 12-25 years participated. A titanium dioxide coating layer was deposited on 0.4572 mm stainless steel orthodontic wires using physical vapor deposition. The coated wires were randomly assigned to one jaw, and the opposite jaw received an uncoated wire as control. Patients were divided into groups according to the duration that wires were in their mouths: A) 1 week, B) 2 weeks, C) 3 weeks, and D) 4 weeks. Block randomization was used to assign patients to each group. At the end of the experiment, 20 mm of each wire (canine-to-canine area) was cut and cultured in S. mutans-specific medium. The culture plates were placed in an incubator containing 5% CO2 for 72 hours at 37 degrees C, and then colonies were counted. MTT was used to test the biocompatibility of the coated and uncoated wires. To evaluate the stability of the coated titanium dioxide layer on the wires, titanium concentration on the saliva was determined using inductively coupled plasma mass spectroscopy. Results: The Kruskal-Wallis test showed that there was no significant difference in colony counts among the coated wires during 1-4 weeks (p&lt;0.48). In the uncoated-wire groups, colonys count at week 1 were higher than weeks 24 -(p&lt;0.022). Wilcoxon\u27s test showed that the number of colonies was significantly different in groups A and C, but there was no significant difference in groups B or D. MTT-assay results showed that there was not a significant difference between cell viability in the coated-wire group and the control. The Kruskal-Wallis test showed that there was no significant difference in titanium concentration in the studied groups (p&lt;0.834). Conclusion: Application of titanium dioxide coating is effective in reducing bacterial adhesion at wire insertion

A bibliometric review of oncolytic virus research as a novel approach for cancer therapy

Background In recent years, oncolytic viruses (OVs) have drawn attention as a novel therapy to various types of cancers, both in clinical and preclinical cancer studies all around the world. Consequently, researchers have been actively working on enhancing cancer therapy since the early twentieth century. This study presents a systematic review of the literature on OVs, discusses underlying research clusters and, presents future directions of OVs research. Methods A total of 1626 published articles related to OVs as cancer therapy were obtained from the Web of Science (WoS) database published between January 2000 and March 2020. Various aspects of OVs research, including the countries/territories, institutions, journals, authors, citations, research areas, and content analysis to find trending and emerging topics, were analysed using the bibliometrix package in the R-software. Results In terms of the number of publications, the USA based researchers were the most productive (n = 611) followed by Chinese (n = 197), and Canadian (n = 153) researchers. The Molecular Therapy journal ranked first both in terms of the number of publications (n = 133) and local citations (n = 1384). The most prominent institution was Mayo Clinic from the USA (n = 117) followed by the University of Ottawa from Canada (n = 72), and the University of Helsinki from Finland (n = 63). The most impactful author was Bell J.C with the highest number of articles (n = 67) and total local citations (n = 885). The most impactful article was published in the Cell journal. In addition, the latest OVs research mainly builds on four research clusters. Conclusion The domain of OVs research has increased at a rapid rate from 2000 to 2020. Based on the synthesis of reviewed studies, adenovirus, herpes simplex virus, reovirus, and Newcastle disease virus have shown potent anti-cancer activity. Developed countries such as the USA, Canada, the UK, and Finland were the most productive, hence, contributed most to this field. Further collaboration will help improve the clinical research translation of this therapy and bring benefits to cancer patients worldwide.publishedVersio

Serological and molecular investigation of human brucellosis in participants of Famenin brucellosis cohort study, Hamadan, Iran

Background and Objectives: Brucella is an intracellular pathogen that causes brucellosis in humans and animals. This study aimed to assess the results of brucellosis seroprevalence among participants of the Famenin brucellosis cohort with molecular investigation technique and determine Brucella-approved species. Materials and Methods: Following the first phase of the Famenin brucellosis cohort in 2016 which investigated the seroprevalence of brucellosis among 2367 participants in Famenin city, a total of 575 people including all seropositive and some seronegative people were examined again by wright serological tests in 2019. The PCR assay was accomplished on all cases that have wright titers ≥ 1/20 for tracing Brucella DNA using BCSP31 target gene and IS711 locus. Results: Out of 575 studied cases, 145 people had wright titers ≥ 1/20. The PCR reactions of these 145 blood samples were positive in 63/145 (43.44%) tested samples using primers (B4/B5) for Brucella genus detection. In the second PCR assay using specific-primers for Brucella abortus and Brucella melitensis, 18/63 (28.57%) of the samples were diagnosed as B. abortus, and 18/63 (28.57%) were diagnosed as B. melitensis. Conclusion: In this study, using the selected specific genes for the diagnosis of Brucella in the genus and species levels, the PCR technique was evaluated as a promising method for the rapid and safe detection of brucellosis besides the serological test for more accurate detection of brucellosis especially in cases that are not definitive

Bacterial Contamination of Collected Cockroaches and Determination their Antibiotic Susceptibility in Khorramabad City, Iran

Background: Cockroaches are one of the most important carriers of pathogenic microorganisms. Therefore, the pres­ence of cockroaches in public places, especially in hospitals, homes, and restaurants, is dangerous, and threatens the health of society, people, and the environment. The aim of this study was evaluation of bacterial contamination of cock­roaches and the sensitivity of these bacteria to various antibiotics, captured from Khorramabad City, Iran Methods: This descriptive cross-sectional study was performed on 150 cockroaches collected from hospital environ­ments, homes, and restaurants in Khorramabad. The outer surface of the cockroaches was washed with physiological sa­line. The suspension was centrifuged for 5 minutes at 2000rpm. Isolation and identification of bacteria was performed using phenotypic methods. Antibiotic susceptibility testing was performed by disk diffusion method according to Clini­cal and Laboratory Standard Institute (CLSI) guideline. Results: A total of 100 American cockroaches (66.66%), 28 B. germanica (18.66%) and 22 Blatta orientalis (14.66%) were identified. In total, 97.33% of the collected cockroaches were infected with bacteria. The most bacterial infection of the cockroaches was Escherichia coli, coagulase-negative Staphylococci and Bacillus respectively. The overall re­sults of the antibiogram test showed that the identified bacteria were resistant to cephalothin, ampicillin, cefotaxime, and kanamycin antibiotics, semi-sensitive to ciprofloxacin and sensitive to tetracycline, gentamicin, nitrofurantoin, Tri­methoprim/sulfamethoxazole, and Chloramphenicol. Conclusion: Infection of cockroaches with pathogenic bacterial agents in hospital, residential, and restaurant environ­ments, as well as the observation of bacterial resistance to some common antibiotics is worrying

The global, regional, and national burden of stomach cancer in 195 countries, 1990-2017 : a systematic analysis for the Global Burden of Disease study 2017

Background: Stomach cancer is a major health problem in many countries. Understanding the current burden of stomach cancer and the differential trends across various locations is essential for formulating effective preventive strategies. We report on the incidence, mortality, and disability-adjusted life-years (DALYs) due to stomach cancer in 195 countries and territories from 21 regions between 1990 and 2017. Methods: Estimates from GBD 2017 were used to analyse the incidence, mortality, and DALYs due to stomach cancer at the global, regional, and national levels. The rates were standardised to the GBD world population and reported per 100 000 population as age-standardised incidence rates, age-standardised death rates, and age-standardised DALY rates. All estimates were generated with 95% uncertainty intervals (UIs). Findings: In 2017, more than 1·22 million (95% UI 1·19–1·25) incident cases of stomach cancer occurred worldwide, and nearly 865 000 people (848 000–885 000) died of stomach cancer, contributing to 19·1 million (18·7–19·6) DALYs. The highest age-standardised incidence rates in 2017 were seen in the high-income Asia Pacific (29·5, 28·2–31·0 per 100 000 population) and east Asia (28·6, 27·3–30·0 per 100 000 population) regions, with nearly half of the global incident cases occurring in China. Compared with 1990, in 2017 more than 356 000 more incident cases of stomach cancer were estimated, leading to nearly 96 000 more deaths. Despite the increase in absolute numbers, the worldwide age-standardised rates of stomach cancer (incidence, deaths, and DALYs) have declined since 1990. The drop in the disease burden was associated with improved Socio-demographic Index. Globally, 38·2% (21·1–57·8) of the age-standardised DALYs were attributable to high-sodium diet in both sexes combined, and 24·5% (20·0–28·9) of the age-standardised DALYs were attributable to smoking in males. Interpretation: Our findings provide insight into the changing burden of stomach cancer, which is useful in planning local strategies and monitoring their progress. To this end, specific local strategies should be tailored to each country's risk factor profile. Beyond the current decline in age-standardised incidence and death rates, a decrease in the absolute number of cases and deaths will be possible if the burden in east Asia, where currently almost half of the incident cases and deaths occur, is further reduced. Funding: Bill & Melinda Gates Foundation