Activity of some aminoglycoside antibiotics against true fungi, Phytophthora and Pythium species

Abstract

Aims: To investigate the in vitro antifungal and antioomycete activities of some aminoglycosides against true fungi and Phytophthora and Pythium species and to evaluate the potential of the antibiotics against Phytophthora late blight on plants. Methods and Results: Antifungal and antioomycete activities of aminoglycoside antibiotics (neomycin, paromomycin, ribostamycin and streptomycin) and a paromomycin-producing strain (Streptomyces sp. AMG-P1) against Phytophthora and Pythium species and 10 common fungi were measured in potato dextrose broth (PDB) and on seedlings in pots. Paromomycin was the most active against Phytophthora and Pythium species with a minimal inhibitory concentration of 1-10 lg ml )1 in PDB, but displayed low to moderate activities towards other common fungi at the same concentration. Paromomycin also showed potent in vivo activity against red pepper and tomato late blight diseases with 80 and 99% control value, respectively, at 100 lg ml )1 . In addition, culture broth of Streptomyces sp. AMG-P1 as a paromomycin producer exhibited high in vivo activity against late blight at 500 lg freeze-dried weight per millilitre. Conclusions: Among tested aminoglycoside antibiotics, paromomycin was the most active against oomycetes both in vitro and in vivo. Significance and Impact of the Study: Data from this study show that aminoglycoside antibiotics have in vitro and in vivo activities against oomycetes, suggesting that Streptomyces sp. AMG-P1 may be used as a biocontrol agent against oomycete diseases.

In vitro activity, extraction, separation and structure elucidation of antibiotic produced by Streptomyces anulatus NEAE-94 active against multidrug-resistant Staphylococcus aureus

“…Due to their widespread distribution and remarkable capacity to produce a wide range of bioactive compounds [16], Streptomyces species have attracted considerable commercial interest. Soil streptomycetes are major producers of bioactive secondary metabolites [17][18][19][20]. It has been reported that organic solvents always provide a higher efficiency in extracting compounds for antimicrobial activities compared to water-based methods [21,22].…”

Antibacterial to antifungal conversion of neamine aminoglycosides through alkyl modification. Strategy for reviving old drugs into agrofungicides

“…They act by binding to the aminoacyl-transfer RNA decoding A site in ribosomal 16S ribosomal RNA to decrease the fidelity of protein translation. Although generally known as antibacterials, certain classical aminoglycosides are reported to inhibit important crop pathogenic fungal oomycetes, 1 and structurally unusual ones inhibit yeasts and protozoans. 2,3 The application of aminoglycosides to combat crop diseases, however, is controversial as the impact it may have on broader antibiotic resistance is debated and uncertain.…”

“…by neomycin, paramomycin, ribostamycin and streptomycin, although they showed comparatively little activity against several other fungal genera. 1 Consequently, aminoglycosides are more accurately antibacterial or antibacterial and antifungal depending on the nature of chemical tailoring of the constituent amino sugars. Here, we demonstrate the third possibility of antifungal but not antibacterial capabilities.…”

In Vitro Susceptibility of Pythium insidiosum Isolates to Aminoglycoside Antibiotics and Tigecycline

“…Members of the genus Pythium are known to be susceptible to some antibiotics of the tetracycline, macrolide, aminoglycoside, and amphenicol classes (5,6,8,12). McMeekin and Mendoza (9) reported that streptomycin may have a stimulatory or inhibitory effect on P. insidiosum depending on the culture conditions, and Loreto et al (7) described an in vitro inhibitory activity of minocycline against P. insidiosum.…”

“…The absence of ergosterol in the cell wall of this oomycete restrains the treatment of pythiosis with antifungal therapy due to the fact that most antifungal drugs act by inhibiting the synthesis of ergosterol. Radical surgery and immunotherapy are among the best therapeutic options, but the improved cure rates are directly associated with early diagnosis of pythiosis (14).Members of the genus Pythium are known to be susceptible to some antibiotics of the tetracycline, macrolide, aminoglycoside, and amphenicol classes (5,6,8,12). McMeekin and Mendoza (9) reported that streptomycin may have a stimulatory or inhibitory effect on P. insidiosum depending on the culture conditions, and Loreto et al (7) described an in vitro inhibitory activity of minocycline against P. insidiosum.…”