Background The outbreak, and pandemic of COVID-19 causing widespread concerns in all health systems of countries. Virus-carrying aerosols can penetrate the healthy human body and lungs, resulting in rapid transmission. For the first time, in this evidence-based article, the effects of different types of mouthwashes to reduce the viral load were investigated. Also, another aim of this essay is a reduction in viral load in patients with COVID-19 and prevention developing ventilator-associated pneumonia in critically ill patients. Methods Related databases were comprehensively searched for relevant studies. The present study was performed according to the preferred cases for standard systematic reviews (PRISMA). Results Five original studies in which the subject matter was directly evaluated were included. Different types of mouthwashes and viruses were investigated in this study. Conclusions The antiviral mouthwashes play a certainly important role in reducing the viral load of the salivary virus. In the present study, this importance could be proved in two different aspects, that is, the use of mouthwash before dental procedures to reduce the risk of transmission of the virus to the dental team and the use of this mouthwash in COVID-19 patients to help improve systemic problems associated with oral microbial flora.

Members of the genus Clavibacter are economically important bacterial plant pathogens infecting a set of diverse agricultural crops (e.g., alfalfa, corn, potato, tomato, and wheat). Tomato-associated Clavibacter sp. strains account for a great portion of the genetic diversity of the genus, and C. michiganensis sensu stricto (formerly C. michiganensis subsp. michiganensis), causing bacterial canker disease, is considered one of the most destructive seed-borne agents for the crop worldwide. However, current taxonomic descriptions of the genus do not reflect the existing diversity of the strains, resulting in unsatisfactory results in quarantine surveys for the pathogens. In this study, we used all the available genome sequences of Clavibacter sp. strains, including the type strains of newly described subspecies, to provide precise insight into the diversity of tomato-associated members of the genus and further clarify the taxonomic status of the strains using genotypic and phenotypic features. The results of phylogenetic analyses revealed the existence of nine hypothetical new species among the investigated strains. None of the three new subspecies (i.e., C. michiganensis subsp. californiensis, C. michiganensis subsp. chilensis, and C. michiganensis subsp. phaseoli) is included within the tomato-pathogenic C. michiganensis sensu stricto lineage. Although comparative genomics revealed the lack of chp and tomA pathogenicity determinant gene clusters in the nonpathogenic strains, a number of pathogenicity-related genes were noted to be present in all the strains regardless of their pathogenicity characteristics. Altogether, our results indicate a need for a formal taxonomic reconsideration of tomato-associated Clavibacter sp. strains to facilitate differentiation of the lineages in quarantine inspections. IMPORTANCE Clavibacter spp. are economically important bacterial plant pathogens infecting a set of diverse agricultural crops, such as alfalfa, corn, pepper, potato, tomato, and wheat. A number of plant-pathogenic members of the genus (e.g., C. michiganensis sensu stricto and C. sepedonicus, infecting tomato and potato plants, respectively) are included in the A2 (high-risk) list of quarantine pathogens by the European and Mediterranean Plant Protection Organization (EPPO). Although tomato-associated members of Clavibacter spp. account for a significant portion of the genetic diversity in the genus, only the strains belonging to C. michiganensis sensu stricto (formerly C. michiganensis subsp. michiganensis) cause bacterial canker disease of tomato and are subjected to the quarantine inspections. Hence, discrimination between the pathogenic and nonpathogenic Clavibacter sp. strains associated with tomato seeds and transplants plays a pivotal role in the accurate detection and cost-efficient management of the disease. On the other hand, detailed information on the genetic contents of different lineages of the genus would lead to the development of genome-informed specific detection techniques. In this study, we have provided an overview of the phylogenetic and genomic differences between the pathogenic and nonpathogenic tomato-associated Clavibacter sp. strains. We also noted that the taxonomic status of newly introduced subspecies of C. michiganensis (i.e., C. michiganensis subsp. californiensis, C. michiganensis subsp. chilensis, and C. michiganensis subsp. phaseoli) should be reconsidered.

During 2013–2016, 277 tomato fields were surveyed across Iran to monitor the status of bacterial canker of tomato, caused by Clavibacter michiganensis subsp. michiganensis. Altogether, 450 plant samples were collected, both with and without symptoms, from which 35 bacterial strains were recovered. These were positive for the PCR test performed using the Clavibacter‐specific primer pair CMR16F1/CMR16R1. Based on the phylogeny of the gyrB gene sequences, 31, three and one of the 35 strains were identified as C. michiganensis, Microbacterium sp. and Agrococcus sp., respectively. The 31 strains of C. michiganensis were further identified as C. michiganensis subsp. michiganensis (23 strains), C. michiganensis subsp. tessellarius (six strains) and Clavibacter spp. (two strains). This was subsequently confirmed by multilocus sequence analysis (MLSA) of five housekeeping genes (atpD, gyrB, ppk, recA and rpoB). In pathogenicity tests, all 23 strains induced wilting symptoms on tomato plants in greenhouse conditions, while no symptoms were observed on eggplant, bell pepper and chili pepper plants. All evaluated pathogenicity determinant genes (celA, pat‐1, tomA, ppaA, chpC and chpG) were detected in 18 out of 31 C. michiganensis strains, using eight specific primer pairs. Estimation of the number of nucleotide differences, sequence similarity matrix and MLSA clustered two peach‐coloured strains (Tom495 and Tom532) separately from all nine previously described subspecies, thereby suggesting these two strains are a new subspecies of C. michiganensis. However, a detailed taxonomic study using multiphased molecular approaches is needed to delineate a formal taxonomic name for these atypical strains.

The distribution of 10 macronutrients and trace metals in the arable soils of Isfahan Province, their phytoavailability, and associated health risks were investigated; 134 plant and 114 soil samples (from 114 crop fields) were collected and analyzed at harvesting time. Calculation of the soil pollution index (SPI) revealed that arable soil polluted by metals was more severe in the north and southwest of the study area. The results of cluster analysis indicated that Pb, Zn, and Cu share a similar origin from industries and traffic. The concentrations of macronutrients and trace metals in the sampled crops were found in the order of K > Ca > S > Mg > P and Fe > Mn > Zn > Cu > Pb, respectively, whereas calculation of the bioconcentration factor (BCF) indicated that the accumulation of the investigated elements in crops was generally in the order of S ≈ K > P > Mg > Ca and Zn > Cu > Mn > Pb > Fe, respectively. Thus, various parameters including crop species and the physical, chemical, and biological properties of soil also affected the bioavailability of the elements besides the total element contents in soil. Daily intake (DI) values of elements were lower than the recommended daily intake (RDI) levels in rice grains except for Fe and Mn, but for wheat grains, all elements displayed DI values higher than the RDI. Moreover, based on the hazard index (HI) values, inhabitants are experiencing a significant potential health risk solely due to the consumption of wheat and rice grains (particularly wheat grains). Mn health quotient (HQ) also indicated a high risk of Mn absorption for crop consumer inhabitants.

Tomato bacterial canker caused by Clavibacter michiganensis subsp. michiganensis is one of the most important seed-borne tomato diseases around the globe. The disease was initially reported in 1993 in Iran, and it became a rising threat for the multibillion dollar tomato industry of the country during the last decade. In this study, using phylogeographic analyses, we determined genetic diversity and geographic distribution of C. michiganensis subsp. michiganensis in Iran. Our field surveys showed that the pathogen is expanding into the southern and eastern areas of the country. Furthermore, multilocus sequence analysis and typing (MLSA/MLST) using the sequences of five housekeeping genes (atpD, gyrB, ppk, recA, and rpoB) revealed that 37 C. michiganensis subsp. michiganensis strains isolated in Iran had high genetic diversity and placed in 15 sequence types (STs), while all the available 184 worldwide C. michiganensis subsp. michiganensis sequences were placed in 43 STs. MLSA divided the worldwide C. michiganensis subsp. michiganensis strains into two phylogroups (I and II). Among the 37 strains isolated in Iran, 30 strains clustered in phylogroup I, while 7 strains clustered in phylogroup II. Phylogeographic data inferred from the allelic profile of the five housekeeping genes suggested multiple introductions of C. michiganensis subsp. michiganensis inoculum into Iran, while the geographic origin of the Iranian C. michiganensis subsp. michiganensis strains remains undetermined. Further analyses using higher numbers of strains are warranted to decipher the evolutionary history of C. michiganensis subsp. michiganensis in Iran. Additionally, stricter seed/transplant inspections are recommended to reduce the risk of pathogen expansion to areas with no history of the disease. IMPORTANCE Clavibacter michiganensis subsp. michiganensis, the causal agent of tomato bacterial canker disease, is one of the economically important pathogens of solanaceous crops (e.g., eggplant, pepper, and tomato) around the world. The disease occurs in many countries, with a particular importance in regions characterized by high precipitation and humid environmental conditions. As a seed-borne pathogen, C. michiganensis subsp. michiganensis is included in the A2 (high risk) list of quarantine pathogens by the European and Mediterranean Plant Protection Organization (EPPO). Bacterial canker disease was reported for the first time in 1993 in Iran, while the geographic distribution, genetic diversity, and phylogenetic position of the causal agent remain undetermined. In this study, using the multilocus sequence analysis and typing (MLSA/MLST) approach, we provided a phylogeographic scheme for the C. michiganensis subsp. michiganensis strains isolated in Iran. Furthermore, global-scale phylogenetic analyses led to determination of phylogenetic position of Iranian C. michiganensis subsp. michiganensis strains among worldwide population of the pathogen. Based on diversity parameters and population structure, we suggest relatively higher genetic diversity of the bacterial canker pathogen in Iran than has so far been observed in the other areas of the world. Results obtained in this study provide a novel insight into the genetic diversity and population structure of the bacterial canker pathogen on a global scale.