Potent, specific MEPicides for treatment of zoonotic staphylococci

Abstract

24Coagulase-positive staphylococci, which frequently colonize the mucosal surfaces of 25 animals, also cause a spectrum of opportunistic infections including skin and soft tissue 26 infections, urinary tract infections, pneumonia, and bacteremia. However, recent 27 45 robustly inhibit DXR in zoonotic staphylococci, and further, DXR represents a 46 promising, druggable target for future development. 3 47 48 Author Summary 49 The proliferation of microbial pathogens resistant to the current pool of antibiotics is a 50 major threat to public health. Drug resistance is pervasive in staphylococci, including 51 several species that can cause serious zoonotic infections in humans. Thus, new 52 antimicrobial agents are urgently need to combat these life-threatening, resistant 53 infections. Here we establish the MEP pathway as a promising new target against 54 zoonotic staphylococci. We determine that fosmidomycin (FSM) selectively targets the 55 isoprenoid biosynthesis pathway in zoonotic staphylococci, and use forward genetics to 56 identify the transporter that facilitates phosphonate antibiotic uptake. Employing this 57 knowledge, we synthesized a series of potent antibacterial prodrugs that circumvent 58 the transporter. Together, these novel prodrug inhibitors represent promising leads for 59 further drug development against zoonotic staphylococci. 60 61 65 zoonotic infections in humans that are clinically indistinguishable from infections with S. 66 aureus including pneumonia, skin and soft tissue infections, hardware infections, and 67 bacteremia(1-5). Newer clinical microbiological techniques, such as mass 68 spectrometry, now readily distinguish S. aureus from zoonotic coagulase-positive

Antimicrobial prodrug activation by the staphylococcal glyoxalase GloB

“…We have recently employed lipophilic prodrugging strategies to increase the efficacy of broad-spectrum antimicrobial phosphonate antibiotics. Notably, POM ester modification of a phosphonate isoprenoid biosynthesis inhibitor (ERJ) increases antistaphyloccal activity by 200-and 500-fold for S. schleiferi and S. pseudintermedius, respectively (27). Similar dramatic potency gains are observed for the same class of compounds against Mycobacterium tuberculosis, Yersinia pestis, Franciscella novicida, and the malaria parasite, Plasmodium falciparum (16,(28)(29)(30)(31).…”

“…In our previous study, we identified phosphonate antibiotics with activity against zoonotic staphylococci (S. schleiferi and S. pseudintermedius) (27). Lipophilic carboxy ester prodrug modification of these phosphonates dramatically increases antistaphylococcal potency, presumably through increased cellular penetration (Fig.…”

“…1A, B). However, prodrug modifications block direct engagement of inhibitors with their enzyme target (27). For this reason, we hypothesized that one or more staphylococcal esterases were required for intracellular prodrug activation (Fig.…”

“…In our strategy, we took advantage of inhibitor pairs with the same target engagement, with and without prodrug modification. We employed the phosphonate antibiotic ERJ, which selectively inhibits the intracellular enzyme deoxyxylulose phosphate reductoisomerase (DXR), and POM-ERJ, the bis-pivaloyloxymethyl prodrug form of ERJ, which inhibits intracellular DXR even though it has been shown to lack direct activity against purified recombinant DXR in vitro (27).…”

“…We sought to enrich for staphylococcal strains that were resistant to prodrugged inhibitors (e.g. POM-ERJ) but remained sensitive to the parent phosphonate ERJ itself (27). For this reason, we first isolated staphylococcal colonies that arose from solid media containing POM-ERJ.…”