Delftibactin-A, a Non-ribosomal Peptide With Broad Antimicrobial Activity

Abstract

The rapid emergence of drug resistant bacteria is occurring worldwide, outpacing the development of new antibiotics. It is known that some of the main sources of antibiotics are the bacteria themselves, many of which are secondary metabolites of Gram positive bacteria. Siderophores, which are secondary metabolites, function as natural chelators (e.g., iron). They are produced and secreted by many bacteria and have been experimented on as “carriers” of several types of antibiotics that pass the cell membrane of challenging Gram negative bacteria. Delftibactin A is a non-ribosomal peptide (NRP), which is known to detoxify gold in Delftia spp. and form gold nuggets, and is considered to be a siderophore. In this study we demonstrate that the supernatant from novel environmental isolates of Delftia spp. have antimicrobial activity. We characterized the active fraction and identified delftibactin A as a compound with antimicrobial activity. Delftibactin A exhibits potent antimicrobial activity against Gram positive multi drug resistant (MDR) bacteria like Methicillin-resistant Staphylococcus aureus (MRSA), and Vancomycin resistant Enterococcus (VRE), and also against the Gram negative pathogens Acinetobacter baumannii and Klebsiella pneumoniae. We discovered that the production of delftibactin A is greatly influenced by temperature. Furthermore, we have demonstrated the possibility of utilizing delftibactin A as a siderophore carrier of toxic metals such as gallium into Gram negative bacteria. These findings expose new opportunities of yet unexploited natural products such as delftibactin A, which have been known for other bacterial uses, as potent factors in the battle against MDR bacteria.

Delftia acidovorans secretes substances that inhibit the growth of Staphylococcus epidermidis through TCA cycle-triggered ROS production

“…A previous study demonstrated that D. acidovorans secreted heat-stable antimicrobial substances that inhibit the growth of S. aureus [23]. Therefore, we assessed the inhibitory activity of D. acidovorans heat-treated CS against S. epidermidis.…”

“…Delftia acidovorans, a gram-negative bacterium, is detected in the skin of AD patients by microbiome analysis [18][19][20][21][22]. D. acidovorans secretes a compound with antimicrobial activity against S. aureus, Enterococcus faecalis, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa [23]. Thus, D. acidovorans may affect bacterial growth in the skin microbiome, but the effect of D. acidovorans on the growth of S. epidermidis remains unclear.…”

Dominant egg surface bacteria of Holotrichia oblita (Coleoptera: Scarabaeidae) inhibit the multiplication of Bacillus thuringiensis and Beauveria bassiana

“…At the genus level, the composition of Clostridium , Enterococcus , Pseudomonas , Acinetobacter , Desulfovibrio , Delftia , Sphingobium , Brevundimonas , Comamonas , Dysgonomonas , Emticicia , Empedobacter and Sebaldella significantly increased in egg surface (Table S6 ), some of which have also been reported to exhibit antimicrobial activity against various pathogens. For example, many species of genus Pseudomonas have been proved synthesize a variety of compounds with antagonistic activity 28 , 34 ; species of Delftia and Sphingobium produce antimicrobial compounds, which inhibit the growth of some common pathogenic microbes 35 , 36 . The further confrontation culture analysis confirmed the antimicrobial activity of egg surface bacteria against Bt and Bb, and the secondary metabolite analysis demonstrated the potential biosynthesis ability of antimicrobial compounds in these anti-pathogen isolates.…”

Dominant Egg Surface Bacteria of Holotrichia Oblita (Coleoptera: Scarabaeidae) Inhibit The Multiplication of Bacillus Thuringiensis and Beauveria Bassiana

“…Many species of genus Pseudomonas have been proved synthesize a variety of compounds with antagonistic activity 32,46 . Species of Sphingobium and Delftia are also producing antimicrobial compounds, such as delftibactin A, which inhibit the growth of some common pathogenic microbes 47,48 . These species may play an important role in the defense process of H. oblita larvae against biocontrol agents.…”