مجله دانشگاه علوم پزشکی مازندران
پیاپی 193 (بهمن 1399)

Pseudomonas aeruginosa is an indispensable pathogenic agent that can lead to serious infections. Antibiotic resistance is really common among bacteria, so, new therapeutic agents could be of great help in overcoming this problem. Based on previous studies, probiotic strains have a protective effect against pathogenic or Image result for opportunist bacteria opportunistic bacteria thorough various mechanisms. The main purpose of the present study was to evaluate the influence of E. coli Nissle 1917 as a probiotic strain on Pseudomonas aeruginosa strains.

In this experimental study, MIC and Disk Diffusion techniques were used to investigate the effect of E. coli Nissle 1917 on Pseudomonas aeruginosa strains. Effect of antibacterial activity of the probiotic strain was evaluated after 24h at 37°C.

The highest concentration of E. coli Nissle 1917 showed the most effective antibacterial activity against clinical and standard Pseudomonas aeruginosa strains after 24h.

Probiotic bacteria can have a positive effect on medical aspects, especially because of having access to numerous antibiotic resistance pathways. Therefore, due to lack of suitable antibiotics for several infections, probiotics could be highly helpful. Various concentrations of probiotic bacteria can also inhibit the pathogenic strain.

Increasing prevalence of obesity over the past few decades constitutes a global health challenge. Recent evidence suggests that gut microbiota may contribute to weight control. So, the present study aimed at comparing the frequency of different bacteria in gut microbiota between obese and normal weight people in Iran.

Thirty normal weight (BMI of 18.5- 25 kg/m²) and 27 obese adults (BMI of 30 kg/m² or higher) were included in this case-control study. Dietary intake was assessed using food frequency questionnaire (FFQ). Anthropometric measurements and collection of blood and faecal samples were also done. Then, gut microbiota composition was assessed using quantitative real-time PCR.

The mean age of participants and concentrations of fasting blood glucose and insulin, insulin resistance index, triglyceride concentration and hsCRP were higher in obese group than the normal group (P<0.05). The frequency of Akkermansia was significantly higher in individuals with normal weight than obese individuals (P=0.003). On the other hand, the frequencies of Prevotella and Lactobacillus genera were higher in obese individuals (P>0.05).

In this study, the frequencies of some bacterial genera of intestinal microbiota were significantly different between obese and normal weight individuals. Therefore, population-based studies are needed to confirm current findings. Moreover, in order to achieve personalized medicine goals, information on gut microbiota composition could be helpful.

Precision medicine is a new approach in medical sciences aimed at individualizing treatment, reducing adverse drug reactions (ADRs), and decreasing health care costs. Precision medicine is also able to maintain the health of individuals by regulating their composition of microorganisms (microbiota) using specific methods. Microbiota is the total stock of microbial species in different organs of a human body and their set of genes are called microbiome. The composition of microbiota is unique in each individual and is directly associated with genetic and invironmental facors, including lifestyle, and certain medications. The human gut is strongly influenced by bacterial communities. Evidence suggests that gut microbiota is involved in oncological diseases. Therefore, microbiota plays a key role in maintaining human health and reducing the risk of diseases in unstable environments. Generally, the microbiome appears to be a vital part of the precision medicine approach, since it leads to interpersonal diversity in all facets of a disease and also represents a changeable component that could increasingly be considered as a therapeutic target and improve drug resistance and responses. In this review, we highlight the importance of the gut microbiota and microbiome in cancer and their functions as therapeutic biomarkers in precision medicine approach.

Some organisms may modulate a healthy state or cause disorders by disruption or induction of several signaling pathways in human body. According to recent evaluations, numerous metabolic disorders such as diabetes, obesity, cardiovascular diseases, mental disorders, and cancers are as the result of bacterial interactions with the host. Various species of the bacteria, called commensal microbiota, live in normal human body which modulate some of the host critical functions by different mechanisms. Induction of epigenetic modifications in host cells that are important in the maintenance of homeostasis or induction of disorders is amongst these mechanisms. Indeed, different factors may induce epigenetic modifications. For example, diet and its effect on microbiota community may epigenetically change the expression of some specific genes. Such modifications may also be dangerous and inherited to next generations. The current review tried to explain the inter-talk between gut microbiota and epigenetic modifications in health and disorders.

There are some evidences about the effects of probiotics on controlling different types of diabetes and reviewing these studies could be of great help in clarifying the efficacy of these dietary supplements in management of diabetes. Thus, we aimed to review the role of probiotics on glycemic control and other biochemical parameters in patients with diabetes.

An umbrella review of systematic reviews, meta-analyses, systematic reviews and meta-analysis in English and Persian were performed by thorough search in PubMed and Scopus. Eligible studies on the effects of probiotics in patients with diabetes published up to 30 September 2020 were selected.

Thirty one eligible papers were identified. In these studies, the effects of probiotic supplements or probiotic food products on glycemic status (n=18), lipid profile (n=12), inflammatory and oxidative stress factors (n=11), blood pressure (n=4), and Body Mass Index (n=2) in patients with type 2 diabetes and gestational diabetes were investigated.

Findings revealed positive effects of probiotic supplements on glycemic status, lipid profile, blood pressure, oxidative stress and inflammation in patients with type 2 diabetes, and gestational diabetes. However, due to high heterogeneity in some parameters, further high quality double-blind clinical trials can shed light on the effectiveness of these supplements.

Diabetic foot ulcer (DFU) is one of the common reasons for non-traumatic amputation of the lower limbs, which requires proper diagnosis, proper collection of specimens, careful selection of antibiotics, treatment of infection based on the disease condition, quick decision about whether or not surgery is necessary and other types of wound care. Probiotics are suggested as non-pathogenic microorganisms due to antibiotic resistance in the treatment of DFU. The effects of probiotics on immune function, skin diseases, and diabetes have been studied and recent evidence suggests their effect on DFU through controlling hyperglycemia, improving immune function, and modulating the microbiota as possible mechanisms. In this review article, we discuss the role of probiotics in healing chronic infected wounds of the diabetic foot from several perspectives including the role of microbiota in glycemic control, the effect of probiotics on the immune system, inflammatory markers, wound healing acceleration, and infection control. Topical application and oral intake of probiotics, especially when used as adjunctive therapies with antibiotics, seems to facilitate the healing process of infected diabetic foot ulcers.

Diabetes and obesity are among the most important metabolic disorders which are of worldwide concern. Today, it has been proven that the diversity and composition of the intestinal microbiota play a key role in the incidence and control of metabolic diseases via regulating the metabolism and immune responses of the host. Previous studies reported links between Akkermansia muciniphila, a commensal bacterium in the gut microbiota, and obesity and diabetes. Human and animal studies have shown that this mucin-degrading bacterium is effective in preventing obesity and diabetes by reducing intestinal wall permeability and preventing metabolic endotoxemia and inflammation, as well as modulating energy and fat metabolism. New evidence shows that both forms of the A. muciniphila (live bacterium or its pasteurized form) can control the disease. Considering the difficulties of the survival and cultivation of this anaerobic bacterium and in order to help optimal use of A. muciniphila in clinical treatments of metabolic diseases, in this study we compared the effect of live and pasteurized A. muciniphila. Besides, we investigated the effects of this bacterium as the next generation of probiotics on obesity and management of diabetes.

Non-responsiveness or poor responsiveness to vaccines are challenging issues in vaccine development, and efforts have been made to find out the potential reasons for these conditions. Intestinal microbiome plays a key role in regulating and development of immune system and the composition and diversity of microbiota in different individuals on the one hand, and the imbalance of intestinal microbial population (Dysbiosis) on the other hand, could be considered as the most effective factors on the human immune system’s response to vaccines. Herein, we reviewed studies on the relationships between gut microbiome and immune response to vaccines. It is known that higher relative abundance of Actinobacteria and Firmicutes could induce more effective immune response to vaccines. In contrast, higher relative frequencies of Proteobacteria and Bacteroidetes are reported in weak immune response to vaccines. There is a strong interaction between the development of immune system and the composition of microbiota throughout life, therefore, it is important to determine the best times for examinations and using the most accurate methods, including sequencing the entire genome and Next Generation Sequencing (NGS). However, interpretation of the results of these researches depends on study designs, inclusion/exclusion criteria, timing of sampling according to the time of vaccination, and the methods used in each study. These considerations could lead to more reliable results and provide better understanding on the crosstalk between microbiota and immune response to vaccines, which will consequently improve vaccine efficacy.

Hepatitis B and C viruses are major public health problems. These viruses can chronically lead to liver disease such as fibrosis, cirrhosis, and hepatocellular carcinoma, which often increase mortality in these patients. According to previous studies, the liver is highly affected by changes in the microbiota of gastrointestinal tract and immune system damage caused by inflammation due to viral hepatitis. Significant advances have been made in identifying gastrointestinal microbiota in cirrhotic patients associated with viral hepatitis and its use in their prognosis and treatment in recent years. Unique bacterial profiles are observed in cirrhotic patients associated with viral hepatitis, including increased numbers of Streptococcus, Prevotella, Staphylococcus, and Enterococcus, as well as decreased numbers of Clostridium and Ruminococcus. The purpose of this review was to summarize and discuss the gastrointestinal microbiota profile in patients with chronic hepatitis B and C and its role in the progression of cirrhosis.

Cognitive disorders are one of the major public health issues in older population worldwide. Problems in forming and storing new memories, short-term memory impairment, and other cognitive problems are common symptoms of cognitive disorders that have no definite treatment yet. Recent studies have shown an association between gut microbiota and cognitive impairments described as microbiota-gut-brain axis. It seems that gut microbiota is able to influence behavior, brain system, and cognitive functions through this pathway in old age. In this review, the underlying mechanisms of the effect of gut microbiota on cognitive disorders and the role of dietetic intervention with probiotics in cognitive function are discussed.

According to the World Health Organization, viable probiotics could have health effects. However, in recent years, many benefits have been observed through application of inactive and non-viable cells of microbes or their metabolites. Therefore, probiotics could be defined as viable, inactive, or non-viable microbial cells or cell extracts that have beneficial health effects on the host. Based on the proposed terminology, probiotics are divided into three categories: real probiotics, pseudo-probiotics, and ghost probiotics. This article reviewed the beneficial effects and underlying mechanisms of inactive and non-viable microbial cells on the host. Also in this article, new proposed terms are described based on the nature of the cell or active ingredient so that it could cover all aspects of the microbial cell (viable, non-viable, inactive, and cell extract).

Personalized nutrition is a new approach in medical sciences that is based on genetic profile, individual needs, and environmental conditions considering health status and chronic diseases of every person. Studies have shown that genetic differences cannot solely justify various responses to medications and diets, and other important factors including gut microbiota are also involved. Human body hosts an active and dynamic ecosystem composed of a large number of microorganisms consisting of genes about ten times more than the human genome. Gut microbiota interacts with the human body through releasing metabolites such as short-chain fatty acids and secondary bile acids and fermentation products such as kynurenine, indoles and indole derivatives, tryptophan, serotonin, histamine, and dopamine. Body weight, metabolic rate, and health and diseases are formed as a result of these interactions.

Extracellular vesicles, naturally released from all cell types including bacteria, are of great importance in medical microbiology due to transporting a variety of biomaterials, enzymes, and virulence factors, regulating immunity, and having roles in colonization and initiation of signaling pathways. These vesicles are also secreted from microbiota in the gastrointestinal tract and affect the host through various mechanisms by causing many systematic, metabolic, and physiological changes. Nowadays, the role of these vesicles is proven in maintaining gastrointestinal homeostasis, the pathogenesis, and diagnosis of related diseases such as obesity, diabetes, cancer, inflammatory bowel disease, mental disorders, and infectious diseases. Effective use of these characteristics could be possible by modulating the microbiota and its metabolites and using extracellular vesicles derived from probiotics. Therefore, the study of these vesicles as microbiota-derived products and next generation probiotics offers a new approach in clinical studies. The present study investigates how the microbiota-derived extracellular vesicles affect the hostchr('39')s health and play underlying roles in various diseases.

Gut microbiota regulates the production of signaling molecules, such as serotonin or 5-Hydroxytryptamine: 5-HT in the host. Serotonin is a biogenic amine that acts as a neurotransmitter in the gut and brain. There is a perfect interaction between human gastrointestinal microbiota and the serotonin system. The gut microbiota plays an important role in the serotonin signaling pathways through the gut-brain axis. It also has a major role in the pathophysiology of serotonin-related metabolic and physiological diseases. The aim of this review was to investigate the relationship between gut microbiota and their role in regulating peripheral serotonin levels. This study could be highly important since there is paucity of information on the relationship between intestinal microbiota and the serotonin system. Numerous studies have shown that changes in the gut microbiota may modulate serotonin signaling system. Also, any disorder in the serotonin system and lack of homeostasis in this system can be effective in the homeostasis shift of intestinal microbiota to dysbiosis and ultimately play a role in causing inflammation in the intestine and gastrointestinal disorders. Evidence on the exact mechanisms of the interaction between intestinal microbiota and serotonin levels indicates a link between intestinal microbiota and this system. Current review showed that gut microbiota could affect the serotonin system through the gut-brain axis. Serotonin signaling in the gut-brain axis could be considered in new therapies to improve serotonin-related disorders. Therefore, further studies are proposed to more accurately determine the association between the gut microbiota and the serotonin system.

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder that affects 8-13% of women at reproductive age worldwide. This disorder is usually associated with menstrual disorders, infertility, obesity, and insulin resistance. The underlying cause of this syndrome is unknown, however in recent years, researchers have shown an association between intestinal microbiota alterations )dysbiosis( and many types of endocrine diseases. Therefore, this review article aimed to improve understanding about the role of intestinal microbiome in development and progression of polycystic ovary syndrome and the underlying mechanisms of this disease. Based on recent findings on the role of intestinal microbiota in the development of this disease, metabolic control may help to prevent that, however it is not yet conclusive. Exploring possible underlying mechanisms is of particular importance for providing new treatment approaches in women with polycystic ovary syndrome. Studies showed that modification of intestinal microbiome in women with PCOS using probiotics, prebiotics, synbiotics, and fecal microbiota transplantation could be effective in improving many of the symptoms of this syndrome and preventing further complications. Therefore, gut microbiota modification is recommended to be considered along with other common treatments. Of course, more research is needed in this field.

Gastrointestinal symptoms along with respiratory symptoms recorded in patients with Covid-19 indicate the role of microbiota in this disease. The purpose of this scientometric study was to assess the articles published on the relationship between microbiota and Covid-19 in order to control the pandemic by reaching new strategies.

Relevant articles were searched in Scopus database by titles and abstracts, published from January 1 to October 15, 2020. Data analysis was performed by analysis tools available in Scopus database, SPSS and VOSviewer network analysis version 1.6.15.

Overall, 87 papers were included. The most productive time was July in which 20 articles were published. The top subject area was medicine (n=66 papers). The first productive country was the USA (24.14%), and the top institute was the Chinese University of Hong Kong (8.54%) in China. The top source was the Lancet Gastroenterology and Hepatology journal that published 8.05% of the articles. Total number of citations were 401 and their H‑index was 9. Top author and top country in the co-authorship network assessment or international collaboration were from China and the USA, respectively. From the Middle East, six articles were published on microbiota and Covid-19 by Iran, Jordan, Qatar, and Turkey and the highest cited article (5 times) was  from Jordan.

Some research has been carried out to investigate the role of microbiota in developing Covid-19. However, further studies are needed to clarify this role.