Detection of human enteric viruses in fresh produce of markets, farms and surface water used for irrigation in the Tehran, Iran

Considering the major role of vegetables in the transmission of gastrointestinal diseases, investigation of the presence of gastrointestinal viruses is particularly important for public health. Additionally, monitoring and investigating potential points of contamination at various stages of cultivation, harvesting, and distribution can be important in identifying the sources of transmission. This study was conducted with the aim of identifying norovirus, adenovirus, hepatitis A virus, hepatitis E virus, rotaviruses, and astroviruses in vegetable samples from the fields and fruit and vegetable centers of Tehran City, and to investigate their presence in irrigation water by RT-qPCR. This study was carried out in two phases: initial and supplementary. During phase I, a total of 3 farms and 5 fruit and vegetable centers and a total of 35 samples from farms, 102 samples from fruit and vegetable centers and 8 agricultural water samples were collected. Zero, 16 and 1 samples were positive for at least one of the viruses from each of the sources, respectively. During phase II, 88 samples from 23 farms, 226 samples from 50 fruit and vegetable centers and 16 irrigation water samples were collected, with 23, 57 and 4 samples were positive for at least one virus, respectively. Rotavirus was the most frequently identified virus among the samples, followed by NoV GII, NoV GI, AstV, and AdV. HAV and HEV were not detected in any of the tested samples. The results of this study suggest that there may be a wide presence of viruses in vegetables, farms, and fruit and vegetable centers in Tehran City, which could have significant consequences considering the fact that many of these foods are consumed raw. Additionally, the detection of some of these viruses in irrigation water suggests that this may be a potential route for viral contamination of produce.

Label-Free Detection of Cardiac Biomarkers: A Review on Microfluidic Electrochemical Biosensors

Biosensors are valuable tools for the detection of biological species, including cells, pathogens, proteins, and other biological molecules. Biosensing devices integrated with microfluidics not only allow for easier sample preparation, portability, and reduced detection time and cost but also offer unique features such as label-free detection and improved sensitivity. Cardiovascular diseases (CVDs), particularly acute myocardial infarction, which is considered one of the main causes of death, are currently diagnosed by electrocardiography (ECG), which has been proven to be inadequate. To overcome the limitations of ECG, the efficient detection of cardiac biomarkers and specifically the measurement of cardiac troponins (cTnT and cTnI) are suggested. This review aims to expound on microfluidics, the most recent materials to develop these devices, and their application in medical diagnosis, particularly in CVD detection. Moreover, we will explore some of the prevalent and last readout methods to investigate in-depth electrochemical label-free detection methods for CVDs, primarily based on voltammetry and electrochemical impedance spectroscopy, with the main focus on structural details.

Multifunctional Carbon-Based Nanoparticles: Theranostic Applications in Cancer Therapy and Diagnosis

Cancer diagnosis and treatment are the most critical challenges in modern medicine. Conventional cancer treatments no longer meet the needs of the health field due to the high rate of mutations and epigenetic factors that have caused drug resistance in tumor cells. Hence, the search for unique methods and factors is quickly expanding. The development of nanotechnology in medicine and the search for a system to integrate treatment and diagnosis to achieve an effective approach to overcome the known limitations of conventional treatment methods have led to the emergence of theranostic nanoparticles and nanosystems based on these nanoparticles. An influential group of these nanoparticles is carbon-based theranostic nanoparticles. These nanoparticles have received significant attention due to their unique properties, such as electrical conductivity, high strength, excellent surface chemistry, and wide range of structural diversity (graphene, nanodiamond, carbon quantum dots, fullerenes, carbon nanotubes, and carbon nanohorns). These nanoparticles were widely used in various fields, such as tissue engineering, drug delivery, imaging, and biosensors. In this review, we discuss in detail the recent features and advances in carbon-based theranostic nanoparticles and the advanced and diverse strategies used to treat diseases with these nanoparticles.

The detection of SARS-CoV-2 RNA in indoor air of dental clinics during the COVID-19 pandemic

In the indoor environment of dental clinics, dental personnel and patients are exposed to a risk of infection because of the transmission of SARS-CoV-2 via particles or droplets. This study investigated the presence of SARS-CoV-2 RNA in indoor air of dental clinics in Tehran, Iran. Air sampling was done (n = 36) collecting particulate samples on PTFE filters at flow rates of 30 to 58 L/min. The samples were analyzed with novel coronavirus nucleic acid diagnostic real-time PCR kits. Only 13 out of 36 samples were positive for SARS-CoV-2 RNA. Logistic regression showed that sampling site's volume, PM_2.5 concentration, number of people, and number of active patient treatment units were significantly positively related with the presence of SARS-CoV-2 RNA. Thus, strategies to control the spread of COVID-19 should include reducing the number of infected people in dental clinics, adding filtration systems, and/or improving ventilation conditions.

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 β-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.

Detection of SARS-CoV-2 RNA in selected agricultural and food retail environments in Tehran, Iran

The SARS-CoV-2 pandemic has and continues to impose a considerable public health burden. Although not likely foodborne, SARS-CoV-2 transmission has been well documented in agricultural and food retail environments in several countries, with transmission primarily thought to be worker-to-worker or through environmental high touch surfaces. However, the prevalence and degree to which SARS-CoV-2 contamination occurs in such settings in Iran has not been well documented. Furthermore, since SARS-CoV-2 has been observed to be shed in the feces of some infected individuals, wastewater has been utilized as a means of surveilling the occurrence of SARS-CoV-2 in some regions. This study aimed to investigate the presence of SARS-CoV-2 RNA along the food production and retail chain, from wastewater and irrigation water to vegetables in field and sold in retail. From September 2020 to January 2021, vegetables from different agricultural areas of Tehran province (n = 35), their irrigated agricultural water (n = 8), treated wastewater mixed into irrigated agricultural water (n = 8), and vegetables collected from markets in Tehran (n = 72) were tested for the presence of SARS-CoV-2 RNA. The vegetable samples were washed with TGBE buffer and concentrated with polyethylene glycol precipitation, while water samples were concentrated by an adsorption-elution method using an electronegative filter. RT-qPCR targeting the SARS-CoV-2 N and RdRp genes was then conducted. SARS-CoV-2 RNA was detected in 51/123 (41.5%) of the samples overall. The presence of SARS-CoV-2 RNA in treated wastewater, irrigation water, field vegetables, and market produce were 75, 37.5, 42.85, and 37.5%, respectively. These results indicate that SARS-CoV-2 RNA is present in food retail and may also suggest that produce can additionally be contaminated with SARS-CoV-2 RNA by agricultural water. This study demonstrates that SARS-CoV-2 RNA was detected in waste and irrigation water, as well as on produce both in field and at retail. However, more evidence is needed to understand if contaminated irrigation water causes SARS-CoV-2 RNA contamination of produce, and if there is a significant public health risk in consuming this produce.

Moore swab performs equal to composite and outperforms grab sampling for SARS-CoV-2 monitoring in wastewater

Wastewater-based epidemiology (WBE) approaches to detect SARS-CoV-2 in municipal wastewater can provide unique information on the incidence or prevalence of COVID-19 in community. However, there are several technical challenges coupled with sewage sampling for SARS-CoV-2, including intermittent shedding of viruses, sampling time, volume, and frequency. Sampling schemes thus may need to be tailored to reach out highly sensitive, accurate, and reliable results. Herein, we compared the accuracy and threshold cycle (Ct) profiles of SARS-CoV-2 in Moore swabs, composite (16-h), and grab samples taken from sewage manholes (n = 17) at the Middle Eastern city of Tehran, Iran, on two occasions (November 2020 and May 2021). Samples were concentrated by polyethylene glycol precipitation and the corresponding Ct values for CDC 'N' and 'ORF1ab' assays were derived by means of real time RT-qPCR. Overall, the Moore swabs performed equal to samples composited over 16 h for qualitative monitoring, and 34/34 (100%) were positive for SARS-CoV-2. The 'N' assay showed the highest detection frequency as compared to 'ORF1ab'. The mean Moore swab Ct profiles were more consistent with 16 h composite sampling as compared with corresponding grab samples, providing hints as to the best sampling protocol to adopt when planning a sewage monitoring campaign particularly under WBE. Furthermore, our analyses on local differences showed somewhat higher virus copy numbers in the southern areas. The experimental design of this study revealed that the Moore swab and composite samples are more sensitive than grab samples, suggesting that the collection of grab samples may be inappropriate for characterizing total number of viral RNA copies in sewage samples. Given the transiently presence of human host-restricted infections such as SARS-CoV-2 and the simplicity and affordability of Moore swab, the method is well suited for disease surveillance in resource poor regions struggling with limited capacity for clinical testing.

The first detection of SARS-CoV-2 RNA in the wastewater of Tehran, Iran

Following the official announcement of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide pandemic spread by WHO on March 11, 2020, more than 300,000 COVID-19 cases reported in Iran resulting in approximately 17,000 deaths as of August 2, 2020. In the present survey, we investigated the presence of SARS-CoV-2 RNA in raw and treated wastewater samples in Tehran, Iran. Untreated and treated wastewater samples were gathered from four wastewater treatment plants over a month period from June to July 2020. Firstly, an adsorption-elution concentration method was tested using an avian coronavirus (infectious bronchitis virus, IBV). Then, the method was effectively employed to survey the presence of SARS-CoV-2 genome in influent and effluent wastewater samples. SARS-CoV-2 RNA was found in 8 out of 10 treated wastewater samples utilizing a reverse transcription-quantitative polymerase chain reaction (RT-qPCR) test to detect ORF1ab and N genes. Moreover, the rate of positivity in wastewater samples increased in last sample collection that shows circulation of SARS-CoV-2 was increased among the population. In addition, the high values detected in effluent wastewater from local wastewater treatment plants have several implications in health and ecology that should be further assessed.

Presence of SARS-CoV-2 in the air of public places and transportation

This study investigated the presence of SARS-CoV-2 in air of public places such as shopping centers, a post office, banks, governmental offices, and public transportation facilities including an airport, subways, and buses in Tehran, Iran. A total of 28 air samples were collected from the eight groups of public and transportation locations. The airborne particle samples were collected on PTFE or glass fiber filters using two types of samplers with flow rates of 40 and 3.5 L/min, respectively. The viral samples were leached and concentrated, and RNA was extracted from each. The presence of viral RNA was evaluated using novel coronavirus nucleic acid diagnostic real time PCR kits. In 64% of the samples, SARS-CoV-2 RNA (62% and 67% from the public places and transportation, respectively) was detected. Positive samples were detected in banks (33%), shopping centers (100%), governmental offices (50%), the airport (80%), subway stations (50%), subway trains (100%), and buses (50%). Logistic regression showed that number of people present during the sampling and the sampled air volume were positively associated with presence of SARS-CoV-2; while the percentage of people with masks, air temperature, and sampling site's volume were negatively related to SARS-CoV-2's presence. However, none of these associations were statistically significant. This study showed that most public places and transportation vehicles were contaminated with SARS-CoV-2. Thus, strategies to control the spread of COVID-19 should include reducing the number of people in indoor spaces, more intense disinfection of transport vehicles, and requiring people to wear masks.

An energy efficient bi-functional electrode for continuous cation-selective capacitive deionization

Effective ion intercalation nanomaterials provide tremendous opportunities to various deionization systems such as capacitive deionization (CDI) to significantly improve the removal capacity of brackish water desalination. However, the asymmetric design of CDI devices causes a low removal rate due to the indispensable regeneration half-cycle. Furthermore, choices of chloride selective electrodes for such devices are limited. This imposes a big challenge on further improvement of CDI systems. Herein, we report a cation-selective CDI system using a single bi-functional Na2VTi(PO4)3@carbon nanomaterial with redox couples of V4+/V3+ and Ti3+/Ti4+ as an advanced symmetric electrode. The as-prepared continuous desalination set-up shows a superior removal rate of 0.022 mg g-1 s-1 (1.32 mg g-1 min-1) with a high half-cycle removal capacity of 35 mg g-1, and extremely low energy consumption of 0.14 W h g-1 (at a current density of 100 mA g-1). In addition, an extremely high cycle-stability of at least 50 cycles is achieved. The bi-functional intercalation mechanism is investigated by in situ XRD and ex situ XPS. The symmetric device yields a simplified and low-cost configuration with improved energy efficiency and high removal capacity. This opens a new horizon towards the commercialization of CDI technologies.