Advanced Resistance Studies Identify Two Discrete Mechanisms in Staphylococcus aureus to Overcome Antibacterial Compounds that Target Biotin Protein Ligase

Abstract

Biotin protein ligase (BPL) inhibitors are a novel class of antibacterial that target clinically important methicillin-resistant Staphylococcus aureus (S. aureus). In S. aureus, BPL is a bifunctional protein responsible for enzymatic biotinylation of two biotin-dependent enzymes, as well as serving as a transcriptional repressor that controls biotin synthesis and import. In this report, we investigate the mechanisms of action and resistance for a potent anti-BPL, an antibacterial compound, biotinyl-acylsulfamide adenosine (BASA). We show that BASA acts by both inhibiting the enzymatic activity of BPL in vitro, as well as functioning as a transcription co-repressor. A low spontaneous resistance rate was measured for the compound (<10−9) and whole-genome sequencing of strains evolved during serial passaging in the presence of BASA identified two discrete resistance mechanisms. In the first, deletion of the biotin-dependent enzyme pyruvate carboxylase is proposed to prioritize the utilization of bioavailable biotin for the essential enzyme acetyl-CoA carboxylase. In the second, a D200E missense mutation in BPL reduced DNA binding in vitro and transcriptional repression in vivo. We propose that this second resistance mechanism promotes bioavailability of biotin by derepressing its synthesis and import, such that free biotin may outcompete the inhibitor for binding BPL. This study provides new insights into the molecular mechanisms governing antibacterial activity and resistance of BPL inhibitors in S. aureus.

A New 1,2,3-Triazole Scaffold with Improved Potency against Staphylococcus aureus Biotin Protein Ligase

“…22,23 Interestingly, the removal of the ribose group of 3 gives rise to the potent SaBPL inhibitor (sulfonamide 6K i : 0.007 ± 0.03 μM) that also displays excellent whole cell activity against S. aureus and MRSA. 12,24 While the triazole-based inhibitors (such as 4 and 5) lack some SaBPL potency and whole cell activity against clinical isolates of S. aureus, they are simpler to prepare than the sulfonamides and thus warrant further investigation. Here, we present a new series of N1-diphenylmethyl 1,2,3-triazoles (7− 13, see Figure 2), with an additional aryl group designed to interact with the entire SaBPL active site, as discussed below.…”

“…Substitution of the phosphoanhydride of 1 for a sulfonamide linker gave 3 , which was potent against a Mycobacterium tuberculosis homologue but inactive against MRSA. , Interestingly, the removal of the ribose group of 3 gives rise to the potent Sa BPL inhibitor (sulfonamide 6 K i : 0.007 ± 0.03 μM) that also displays excellent whole cell activity against S. aureus and MRSA. , …”

Layered Black Phosphorus Nanoflakes Reduce Bacterial Burden and Enhance Healing of Murine Infected Wounds

“…[6,7] Currently, available treatment options for antibiotic-resistant bacteria are becoming scarce, with poor antimicrobial stewardship and only five new classes of antibiotics discovered since 2000, highlighting the urgency to develop new alternative therapies to maintain gold-standard patient care. [1,8] Additionally, current wound dressings are commonly impregnated with antibiotics, antimicrobial agents, and growth factors and can create a sealed anaerobic environment, which favors mature biofilm formation and contributes to impaired wound healing. [9] Nanotechnology involves materials sized within the nanoscale range of 1-100 nm.…”

“…The wound infection “epidemic” is becoming increasingly problematic, with antibiotic resistance mechanisms spreading widely and rapidly. [ 1 ] The impact of antimicrobial resistance has been predicted to result in excess of 10 million deaths by 2050, alongside significant clinical expenditure. [ 2 ] Currently, ≈ 70% of bacteria have developed resistance to at least one common class of antibiotic, suggesting a desperate need for the development of new alternative antimicrobial therapeutics for clinical wound management.…”