Streptomyces: A Potential Source of Natural Antimicrobial Drug Leads
Mahendra Rai, Chistiane M. Feitosa in Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
In the early 1940s, Waksman and Henrici first described the genus Streptomyces (Williams et al. 1983). It was included in the family Streptomycetaceae (Arai 1997) based on physiological and morphological characteristics. Furthermore, some other features, such as the cell wall chemical composition, including the phospholipids/peptidoglycan type, fatty acid chains and the 16S rRNA sequence, are very useful in the taxonomy of this genus (Kämpfer et al. 2008). The genus Streptomyces represents the only member of the family Streptomycetaceae that belongs to Actinobacteria phylum and is classified in Actinomycetales order placed in the class Actinobacteria (Anderson and Wellington 2001). However, Streptomyces is among the richest taxonomic components of known actinomycetes in terms of the number of discovered species (Bhattacharyya et al. 1998), with more than 500 species producing approximately two thirds of the known natural antibiotics (Mohanraj and Sekar 2013). Streptomyces are aerobic, Gram-positive, but not acid-fast bacteria that are also characterized by high guanine/cytosine content (> 70%) (Reza Dehnad et al. 2010) and can grow in different environments (Maleki et al. 2013).
Streptomycin
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Streptomycin is a natural product of the soil actinomycete Streptomyces griseus (Schatz et al., 2005). It is a member of the aminoglycoside class of antibiotics that typically consist of two or more amino-sugars covalently linked to a central aminocyclitol. However, streptomycin differs from most other medically available aminoglycosides in that the aminocyclitol is peripherally rather than centrally located and is a streptidine rather than deoxystreptamine. Aminoglycosides are inhibitors of bacterial protein synthesis, but their action is bactericidal, unlike most other antibiotics that act in this way. Streptomycin is active against Gram-negative aerobic bacilli, some medically important mycobacteria (particularly Mycobacterium tuberculosis), enterococci when combined with a cell wall–active agent, streptococci, and staphylococci (Chambers, 2006).
Bacteria
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
There is a phenomenal variety of shapes and groupings of cells among the prokaryotes. Shapes include the forms historically described as: spherical (cocci), cylindrical (bacilli), either straight or curved (vibrio). The organisms may grow singly or in pairs (diplococci or diplobacilli), in chains (streptococci or streptoba-cilli), in three-dimensional cubes of spheres (sarcinae), or in randomly arranged clusters (staphylococci); in more or less tightly coiled spirals (e.g., spirochaetes), in long sometimes branched filaments (found in Streptomyces and Actinomyces species, among others), in squares, and in irregular clusters. In addition to those already described, groupings of cells include: rosette clusters, flexible gliding clusters, and tightly packed films. It seems reasonable to assume that any possible form, shape or arrangement of bacterial cells may exist somewhere in nature awaiting discovery.
Maculosin, a non-toxic antioxidant compound isolated from Streptomyces sp. KTM18
Published in Pharmaceutical Biology, 2021
Babita Paudel, Rukusha Maharjan, Prajwal Rajbhandari, Niraj Aryal, Saefuddin Aziz, Keshab Bhattarai, Bikash Baral, Rajani Malla, Hari Datta Bhattarai
Streptomyces are Gram-positive bacteria that are found in various environmental conditions and have a filamentous mycelium similar to fungi. Phylogenetically, Streptomyces is a part of Actinobacteria, with high GC-rich (70%) content. Most of them are ubiquitous and highly versatile soil-dwelling saprophytes known to produce diverse secondary metabolites, many of which are well-known antibiotics (Omura et al. 2001; Khan et al. 2011). Antioxidant activities of 30 strains of rare Actinomycetes were reported (Mohammadipanah and Momenilandi 2018) without characterizing the active molecules. Similarly, the broth extract of Streptomyces carpaticus displayed a significant DPPH free radical scavenging activity (IC50, 84.5 µg/mL) (Subramanian et al. 2017); however, the active molecule was not characterized. Thus, besides antibiotics, Streptomyces could be a promising source of antioxidant compounds.
Exposure to Al2O3 nanoparticles facilitates conjugative transfer of antibiotic resistance genes from Escherichia coli to Streptomyces
Published in Nanotoxicology, 2019
Xiaomei Liu, Jingchun Tang, Benru Song, Meinan Zhen, Lan Wang, John P. Giesy
The actinobacterium Streptomyces produces two-thirds of the clinically used antibiotics of natural origin. The model strain Streptomyces coelicolor M145 can generate various industrially important secondary metabolites (Borodina et al. 2008), hence Streptomyces induces important environmental and economic implications. The chromosomes of Streptomyces are among the largest bacterial chromosomes, with sizes in the range of 8 Mb to over 10 Mb (Kirby and Chen 2011). In contrast to most bacteria that divide by binary fission, Streptomyces have complex life cycles that resemble the growth of eukaryotic filamentous fungi (Flärdh and Buttner 2009, Flärdh 2010). It is noteworthy that under laboratory conditions, stimulation such as heat shock is necessary to promote the transfer of plasmids into Streptomyces spores (Moraga et al. 2017). Such stimulation promotes the germination of spores and increases cell membrane permeability, thereby enhancing the propensity to ingest foreign plasmids. Given the stringent requirements of standard experimental conditions, spontaneous initiation of the transfer process is difficult in natural environments. As NPs can also change the permeability of cell membranes, it is thought that exposure to Al2O3 NPs facilitates the ability of cells or spores to uptake ARGs through plasmids even without heat shock, allowing the process to occur easily in the natural environment.
Combined therapy of plantar warts with topical bleomycin and microneedling: a comparative controlled study
Published in Journal of Dermatological Treatment, 2020
Hend D. Gamil, Mohamed M. Nasr, Fathia M. Khattab, Amira M. Ibrahim
Bleomycin is a glycopeptide antibiotic produced by the bacterium Streptomyces verticillus. It acts by inhibiting the deoxyribonucleic acid (DNA) synthesis in cells and viruses; it induces strand cleavage of the DNA molecule (5). Microneedling is a minimally invasive procedure; dermapen designed in a special form to control depth penetration of the skin (6). The microneedles penetrate through the epidermis but do not remove it; so, the epidermis is only punctured and rapidly heals based on the controlled mechanical stimulation of the wound-healing process by the needle (6,7). It has also been shown to augment transdermal drug delivery. By creating micropores through the stratum corneum and into the underlying epidermis, microneedling bypasses the barrier function of the stratum corneum to rapidly deliver topical medications into the dermal microcirculation without penetrating deep enough to stimulate nerves within the dermis. Choice of dermapen becomes important, as bleeding induced by longer needles has been hypothesized to inhibit drug absorption (8). The aim of this study was to assess the efficacy of combination between microneedling with dermapen and topical bleomycin in the treatment of plantar warts in comparison with intralesional bleomycin and intralesional saline.
Related Knowledge Centers
- Antibiotic
- Bacteria
- Genome
- Geosmin
- Metabolite
- Spore
- Actinomycetota
- Streptomycetaceae
- Gram-Positive Bacteria
- Gc-Content