Inhibition of WTA synthesis blocks the cooperative action of PBPs and sensitizes MRSA to β-lactams.
Rising drug resistance is limiting treatment options for infections by methicillin-resistant Staphylococcus aureus (MRSA). Herein we provide new evidence that wall teichoic acid (WTA) biogenesis is a remarkable antibacterial target with the capacity to destabilize the cooperative action of penicillin-binding proteins (PBPs) that underlie β-lactam resistance in MRSA. Deletion of gene tarO, encoding the first step of WTA synthesis, resulted in the restoration of sensitivity of MRSA to a unique profile of β-lactam antibiotics with a known selectivity for penicillin binding protein 2 (PBP2). Of these, cefuroxime was used as a probe to screen for previously approved drugs with a cryptic capacity to potentiate its activity against MRSA. Ticlopidine, the antiplatelet drug Ticlid, strongly potentiated cefuroxime, and this synergy was abolished in strains lacking tarO. The combination was also effective in a Galleria mellonella model of infection. Using both genetic and biochemical strategies, we determined the molecular target of ticlopidine as the N-acetylglucosamine-1-phosphate transferase encoded in gene tarO and provide evidence that WTA biogenesis represents an Achilles heel supporting the cooperative function of PBP2 and PBP4 in creating highly cross-linked muropeptides in the peptidoglycan of S. aureus. This approach represents a new paradigm to tackle MRSA infection.
MG DeGroote Institute for Infectious Disease Research and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.
Maya A
MA
Farha
Alexander
A
Leung
Edward W
EW
Sewell
Michael A
MA
D'Elia
Sarah E
SE
Allison
Linda
L
Ejim
Pedro M
PM
Pereira
Mariana G
MG
Pinho
Gerard D
GD
Wright
Eric D
ED
Brown
D002473:Cell Wall; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D046915:Penicillin-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D013682:Teichoic Acids / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D047090:beta-Lactams / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology
D046915:Penicillin-Binding Proteins; D013682:Teichoic Acids; D047090:beta-Lactams