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There are trillions of microbes residing in our body, with their collective genomes much more than human genomes. They have been living in a close relationship with us and play a role in various biological functions. The human microbes begin to build up in utero, accumulate, and fluctuate until a set point is achieved around three years of age. The gut microbiome is altered by several factors, which include age, diet, and antibiotic use. After the exposure, the microbe may shift back to retain its balance, but some factors may leave a permanent footprint on the gut flora. This may be significant as our review has shown the relationships between microbes and diseases. When the homeostasis of gut-microbes is disrupted, multiple mechanisms have been shown to contribute to diseases' development. The balance between protective and pathogenic microbes must be kept in check to prevent disease onset. With a better understanding of this relationship, we will investigate the potential methods to modify the gut flora as the background of developing therapeutic options. There are already some therapeutic options such as prebiotics, probiotics, and fecal transplantation, but their clinical use is limited and restricted. Therefore, there is still a need to investigate the characteristic microbiome association with gut-dysbiosis-related diseases, which may help manage the disease and develop diagnostic and monitoring tools. This review aims to discuss our gut microbiome and its association with human health and diseases.

The most biological multiplicity on this planet is almost certainly concealed in soils. Many valuable bacteria had been extensively dispersed in soils worldwide, with soils from terrestrial, desserts and Antarctic. Hence, soils become an intensively utilized ecological niche for the inhabitants to generate various useful biologically active natural products such asantibiotics, antifungal, antiviral, antioxidant, neuroprotection, anticancer and other important compounds. Bacteria including Actinobacteria have been exceptionally valuable for the pharmaceutical industry due to their limitless capability to generate secondary metabolites with various biological activities and chemical structure. Therefore, this article aims to provide critical insight of bioprospecting of microbes for valuable compounds to mankind.

Irritable bowel syndrome (IBS) is a chronic disease prevalent in today’s society and diet remains the most common aggravator of IBS symptoms. Existing literature suggest that IBS patients are dysbiotic as evidence indicates decreased levels of Bifidobacteria, Bacteroidetes and Faecalibacterium prausnitzii and increased levels of Firmicutes in comparison to healthy individuals. Studies suggest that changes in diet can modulate gut microbiota and therefore improve IBS symptoms. The two diets being investigated are the low FODMAP diet and the use of probiotics. A low FODMAP diet implements a reduction in the amount of poorly absorbed carbohydrates and probiotics are live microorganisms that have been proven beneficial when consumed appropriately. Based on the literature acquired from PubMed, a positive correlation appears to exist between the low FODMAP diet and IBS symptoms; 57% report symptom relief. There is also a notable effect on the gut microbiome after changing to low FODMAP diet, noted with a significant decrease in levels of Bifidobacterium, Clostridium, F. prausnitzii and Actinobacteria. This poses a concern as bacteria such as Bifidobacteria and F. prausnitzii are beneficial for health. When probiotics are taken amongst IBS patients a reduction in symptoms is also observed. Additionally, there is an increase in the abundance of Bifidobacterium and Lactobacilli. It is suggested that co-administration of probiotics with a low FODMAP diet may ensure beneficial levels of Bifidobacterium while IBS symptoms ameliorate.

Food contamination is a worrying condition faced by us today. We often discuss on the food safety aspect and how to manage contamination. Food products can be tainted by bacteria at any level of food production to human consumption, subsequently developing gastroenteritis. The people from developed and developing countries are at high risk from harmful effects of unsafe food. Of all the foodborne pathogens, Vibrio parahaemolyticus has been accounted for many outbreaks globally and still at rise even with proper management methods. V. parahaemolyticus infection occurs as a result of improper food handling and preparation, ability of the bacterium to withstand human gut to launch virulence, antibiotic resistant bacterium, and failure of regulatory bodies to safe-guard food quality. This scenario poses a global health issue that warrants rapid control measures to ensure food safety from production to consumption by consumers. For that reason, this review aims to provide an overview of the epidemiology of V. parahaemolyticus as well as discuss the challenges faced to encounter this bacterium.

In the class Actinobacteria, the renowned genus Streptomyces comprised of a group of uniquely complex bacteria that capable of synthesizing a great variety of bioactive metabolites. Streptomycetes are noted to possess several special qualities such as multicellular life cycle and large linearized chromosomes. The significant contribution of Streptomyces in microbial drug discovery as witnessed through the discovery of many important antibiotic drugs has undeniably encourage the exploration of these bacteria from different environments, especially the mangrove environments. This review emphasizes on the genus Streptomyces and reports on the diversity of actinobacterial population from mangroves at different regions of the world as well as discovery of mangrove-derived novel Streptomyces species. Overall, the research on diversity of Actinobacteria in the mangrove environments remains limited. A total of 19 novel Streptomyces spp. isolated from mangroves between the year 2009 - early 2019, notably from China, India, Malaysia, and Thailand. Hence, it will be worthwhile to encourage the study of these bacteria from mangroves of different locations.

High consumer demand for seafood has led to the need for large-scale, reliable supply through aquaculture farming. However, bacterial infections - which can spread rapidly among the dense farming area pose a major threat to this industry. The farmers therefore often resort to extensive use of antibiotics, both prophylactically and therapeutically, in order to protect their stocks. The extensive use of antibiotics in aquaculture has been postulated to represent a major contributing factor in the rising incidence of antimicrobial resistant pathogenic bacteria in seafood; which may then lead to the spread of antimicrobial resistant bacteria in the environment as well as posing a significant threat to human health. This study aimed to characterize antibiotic resistance of Vibrio parahaemolyticus from shrimp and shellfish in Selangor, Malaysia. The antibiotic susceptibility of 385 V. parahaemolyticus isolates was investigated against 14 antibiotics followed by plasmid profiling and plasmid curing to determine the antibiotic mediation. A large number of isolates showed resistance to ampicillin (85%), amikacin (66.8%), and kanamycin (50.1%). A notable resistance pattern was also observed to the third generation cephalosporins (cefotaxime 55.8% and ceftazidime 34%). Only 338 V. parahaemolyticus isolates had 1-7 different plasmids and could be categorized into 27 patterns based on the number and pattern of plasmid present. Interestingly, there was no correlation between the number of plasmids and antibiotic resistant patterns seen in the isolates. The antibiotic resistance was mediated by both chromosomal and plasmid mediation among the resistant isolates. In summary, our results demonstrate that incidence of pathogenic V. parahaemolyticus in seafood in Selangor remains in relatively assuring levels, however the identification of antibiotic resistance among the isolates does rises a public health concern and warrants for continuous surveillance.

The 16S ribosomal RNA gene is the gold standard for taxonomic identification and phylogenetic study of most of the bacteria. However, the resolution of 16S rRNA gene is found to be insufficient to distinguish closely related Streptomyces species within the genus Streptomyces due to large size of Streptomyces member. Thus, it is essential to find alternative phylogenetic gene markers with higher discriminatory power in addition to 16S rRNA gene for the phylogenetic analysis of Streptomyces species in order to effectively indicate the evolutionary relationships among Streptomyces members at intra- and inter-specific level. This article aimed to discussed the resolution power of ribosomal genes (16S rRNA and 23S rRNA gene), of protein-coding genes (gyrB and trpB gene) and between ribosomal and protein-coding genes in order to identify gene that could provide better resolution for phylogenetic studies of Streptomyces.

Listeria monocytogenes is a Gram-positive bacterium that is commonly isolated from food sources. This opportunistic human pathogen is the causative agent of listeriosis, an illness that mainly effects immunocompromised, the elderly, infants, and pregnant women. Ever since its detection, listeriosis cases has been very prevalent and commonly associated with food sources such as dairy products, ready-to-eat food, and poultry. The prevalence of listeriosis is of public health concern and proper management is required to control this illness from spreading widely. Thus, this review seeks to elucidate a better understanding on the characteristics, taxanomy, prevalence and their associated food sources, as well as management methods in order to devise proper control actions to reduce listeriosis incidence worldwide.