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Streptomyces: A Potential Source of Natural Antimicrobial Drug Leads
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Mahmoud A. Elfaky, Hanaa Nasr, Ilham Touiss, Mohamed L. Ashour
The Secondary Metabolites (SMs) profiles were changed when Streptomyces fradiae 007 was co-cultured with Penicillium spp. WC-29-5 to supply two additional polyketides with anticancer properties. This method of co-cultivation was deemed to be the most effective. Bacteria can react to the presence of fungal strains by producing different SMs. Indeed, co-cultivation of Aspergillus fumigatus MR2012 and two hyper-arid deserts Streptomyces leeuwenhoekii strains resulted in dual induction of bacterial and fungal metabolites, resulting in the discovery of the new bioactive compounds luteoride D and pseurotin G (Romano et al. 2018).
Monographs of Topical Drugs that Have Caused Contact Allergy/Allergic Contact Dermatitis
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Neomycin is the prototype of the aminoglycoside antibiotics and was first isolated in 1949 from the gram-positive bacillus Streptomyces fradiae. It consists of a variable mixture of two isomers, neomycin B (>88%) and neomycin C (<10%), along with small amounts of a degradation product, neamine or neomycin A (<2%). It exerts its antibacterial activity through irreversible binding of the nuclear 30S ribosomal subunit, thereby blocking bacterial protein synthesis. Neomycin is effective against most gram-negative organisms except Pseudomonas aeruginosa and anaerobic bacteria. Its activity against gram-positive microorganisms is more or less limited to staphylococci, but bacterial resistance supervenes after prolonged use (117,118).
Ene-Reductases in Pharmaceutical Chemistry
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
In the 1960s, fosfomycin (originally phosphonomycin, trade names Monurol and Monuril) was isolated by screening fermentation broths of Streptomyces fradiae within a collaborative project between Merck and the Spanish “Compañía Española de Penicilina y Antibióticos” (CEPA) (Hendlin et al., 1969). The compound exhibited broad antibacterial activity against Gram-positive as well as Gram-negative pathogens, and for more than 20 years, it has been used as an oral treatment for urinary tract infections (Silver, 2017). Due to its unique mode of action—inhibition of murein biosynthesis through irreversible interaction with enzyme MurA—fosfomycin makes cross-resistance uncommon and allows for synergies with other antibiotics (Falagas et al., 2016). In an era of antibiotic resistance and limited new treatment options, fosfomycin is of interest against multidrug-resistant (MDR) and extensively drug-resistant (XDR) nosocomial (hospital-acquired) infections, for which limited treatment options are available. Fosmidomycin, on the other hand, inhibits DXP reductoisomerase, a key enzyme in the non-mevalonate pathway of isoprenoid biosynthesis, and thus is considered for treatment of malaria in combination with for example clindamycin (Ruangweerayut et al., 2008).
Diagnostics and management approaches for Acanthamoeba keratitis
Published in Expert Opinion on Orphan Drugs, 2020
Nóra Szentmáry, Lei Shi, Loay Daas, Berthold Seitz
Neomycin (C23H46N6O13) is a broad-spectrum aminoglycoside antibiotic derived from Streptomyces fradiae and is an antibiotic complex consisting of three components. There are two active components – the isomeric components B and C – and neomycin as the third, minor component. Neomycin irreversibly binds to the 16S rRNA and S12 protein of the bacterial 30S ribosomal subunit, which has the outcome, that this agent interferes with the assembly of the initiation complex between mRNA and the bacterial ribosome, thereby inhibiting the initiation of protein synthesis. Neomycin additionally causes misreading of the mRNA template, creating a translational frameshift, which results in premature termination and eventually leads to bacterial cell death. Its use is indicated for the treatment of bacterial blepharitis, bacterial conjunctivitis, corneal injuries, corneal ulcers, and meibomianitis.
Enhanced production of tanshinone IIA in endophytic fungi Emericella foeniculicola by genome shuffling
Published in Pharmaceutical Biology, 2018
Pengyu Zhang, Yiting Lee, Xiying Wei, Jinlan Wu, Qingmei Liu, Shanning Wan
Classical methods for strain improvement have been applied to successfully produce a number of industrial strains, but they are time-consuming and laborious due to the repeatedly random mutation and selection. Recently, an efficient technology named genome shuffling has made great progresses in the construction of mutants with distinctly and significantly improved phenotype. The tylosin production from Streptomyces fradiae has been rapidly reinforced by two rounds of genome shuffling, although 20 rounds of mutagenesis and screening were required in the past (Zhang et al. 2002). Genome shuffling allows many parental strains with certain phenotypic improvements to be recombined through recursive protoplast fusion. A library of shuffled bacteria with genetic exchange is achieved by repeating the above process. Since the limited knowledge about genome sequence negatively affects the rational application of recombinant DNA techniques to manipulate the strain, genome shuffling exhibits the advantage of recombination between genomes in uncharacterized organisms. This approach has also been used to improve the acid tolerance in Lactobacillus (Patnaik et al. 2002), degradation of pentachlorophenol in Sphingobium chlorophenolicum (Dai and Copley 2004) and production of hydroxycitric acid in Streptomyces (Hida et al. 2007). Moreover, our research group has already applied genome shuffling to improve the acid tolerance and volumetric productivity in Lactobacillus rhamnosus (Wang et al. 2007).
Optimization of process parameters for fabrication of electrospun nanofibers containing neomycin sulfate and Malva sylvestris extract for a better diabetic wound healing
Published in Drug Delivery, 2022
Mohammed Monirul Islam, Varshini HR, Penmetsa Durga Bhavani, Prakash S. Goudanavar, N. Raghavendra Naveen, B. Ramesh, Santosh Fattepur, Predeepkumar Narayanappa Shiroorkar, Mohammed Habeebuddin, Girish Meravanige, Mallikarjun Telsang, Nagaraja Sreeharsha
Neomycin sulfate (NS) is one of the most commonly used topical antibiotics. It is the sulfate salt of neomycin B and C. It is an aminoglycoside antibiotic produced by the growth of Streptomyces fradiae (Nitanan et al., 2013; Geszke-Moritz and Moritz, 2016). It stops proteins from being made by binding to ribosomal RNA, which causes the bacterial genetic code to be read wrong. Except for P. aeruginosa, it kills most Gram-negative bacteria but does not affect anaerobes. Some Gram-positive bacteria, such as staphylococci, are killed by it, but streptococci are not. Neomycin is sold as 20% NS in petrolatum, and it is often mixed with other topical antimicrobials to make it more effective against Gram-positive bacteria. It can be used to treat superficial infections, prevent infections in minor wounds and postsurgery wounds, help treat burns, and deal with secondary infections in long-term skin conditions (Madan et al., 2014; Daneshmand et al., 2018; Paliwal et al., 2020). Even though it is often used to treat stasis dermatitis and chronic leg ulcers, it should be used with care because putting it on skin that is already damaged can cause sensitization, systemic absorption, and possibly systemic toxicity. Another harmful side effect of neomycin is allergic contact dermatitis, which affects 1% to 6% of the population with healthy skin and even more people with damaged skin. Contact dermatitis has been reported in as many as 30% of people with stasis dermatitis or leg ulcers. Neomycin can also cause delayed hypersensitivity, reactions caused by IgE, and anaphylactic reactions. The fact that neomycin could cause resistance is another drawback. Resistance can be caused by plasmids and has been seen in both Gram-positive cocci (like staphylococci) and Gram-negative cocci (like Escherichia coli, Klebsiella, and Proteus) (Madgulkar et al., 2011).