Abstract: Many methods have been developed for studying and comparing bacterial diversity. These methods suffer from a number of drawbacks. Culture-dependent methods have a drawback that only a small number of bacteria can be cultured. Although many modifications in the traditional cultivation approach have been made, such as the use of gellan instead of agar and high throughput dilution to extinction culturing, but a large fraction of microbes still remain uncultured. Culture-independent methods were developed to explore uncultured bacterial diversity but they have their own drawbacks. PCR-based methods have biases during DNA extraction and the removal of substances that may inhibit polymerase activity during PCR and digestion with restriction enzymes. “Omics” approach, i.e., metagenomics, metatranscriptomics, and metaproteomics, aim to link bacterial community structure with function. Different combinations of methods can be used to know more precisely about the bacterial diversity. To date, no known method can reveal the exact bacterial diversity of different environments. This lacuna needs to be filled and newer methods must be developed that can help in exploring the immense bacterial diversity created by nature.
All posts by Anna Białecka
Abstract: Stenotrophomonas maltophilia is an important etiological factor of infections in patients with compromised immune systems, undergoing invasive diagnostic and therapeutic procedures, as well as in those suffering from cancer or cystic fibrosis. It poses a threat primarily to hospitalized patients. Due to its broad natural resistance and increasing acquired resistance, the therapy of infections caused by this pathogen is a challenge for modern medicine. The paper presents the current knowledge about the general characteristics, clinical significance and the most important pathogenicity factors of S. maltophilia. It also discusses therapeutic possibilities, including alternative ones, in infections caused by these microorganisms.
Abstract: Biosurfactants are a group of surface-active agents mainly produced by microorganisms and have a wide range of applications in industries as well as agriculture. Global usage of such biologically active compounds as detergents, bioremediation agents, cosmetic products is hugely dependent on their high production. New avenues of research have opened up due to this increased interest, most of which are focused on identifying specialized microorganisms capable of biosurfactant production. Screening methods for selection of biosurfactant producing bacteria are, therefore, of utmost importance in this endeavor. The aim of this review was to discuss various conventional and novel methods that can overcome the hurdles encountered in time effective, economical microbial biosurfactant screening. This review lists several important biosurfactant screening methods based on supernatant, biomass as well as culture media. New methods devised for biosurfactant screening in the last half decade such as surfactant dependent dye solubilization, metagenomic studies etc. are also explained in detail. A thorough grasp of both contemporary and anachronistic screening methodologies will not only lead to discoveries of novel native strains capable of biosurfactant production but also form the basis on which new screening methods can be devised
Abstract: Enterococcus spp. are a component of the microbiota of humans and animals and are commonly found in the natural environment. They are opportunistic pathogens that can cause infections of various locations. These bacteria rarely cause community-acquired infections. Although they were considered microorganisms with low pathogenic potential, they have become one of the important hospital pathogens recently. Their common occurrence and ability to survive in the hospital environment contribute to the recorded and still increasing frequency of their isolation, also from invasive infections. The species most frequently isolated from infection cases are E. faecalis and E. faecium, which pose therapeutic problems due to their increasing multidrug resistance. Due to the growing clinical importance, mechanisms of natural and acquired resistance to antibiotics, and potential virulence factors, Enterococcus spp. have become the subject of many studies. The aim of the study is to present the current knowledge on the most important virulence factors that may occur in bacteria of the genus Enterococcus, which include: SagA secretory antigen, EfaA protein, Esp surface protein, Ace collagen binding protein, cytolysin, hyaluronidase, hemagglutinin, lipase, serine protease, aggregating substance, extracellular peroxides and gelatinase.
Abstract: The larvae of the insect Galleria mellonella have gained wide acceptance as an in vivo model for the study of virulence in Gram-negative and Gram-positive bacteria and fungi. Importantly, G. mellonella offers an alternative, low-cost, and ethically acceptable method of assessing pathogens. These insects have a number of advantages, including ease of breeding, a rapid developmental cycle, low maintenance costs, and ease of experimental manipulation. Most importantly, G. mellonella larvae have a complete immune system and a nonspecific immune response similar to that of humans, making them a valuable model for studying pathogen-host interactions. Furthermore, using this model, it is possible to test the efficacy of various chemical compounds or natural substances that show antimicrobial activity. In this literature review, we provide a comprehensive overview of recent studies of the use of G. mellonella in virulence analyses and as a platform for testing the efficacy of new drugs.