Open AccessIdentification of Penicillin Binding Protein 4 (PBP4) as a critical factor for Staphylococcus aureus bone invasion during osteomyelitis in mice
Author(s) -
Elysia A Masters,
Karen L. de Mesy Bentley,
Ann Gill,
Stephanie P. Hao,
Chad A. Galloway,
Alec T. Salminen,
Diamond R. Guy,
James L. McGrath,
Hani Awad,
Steven R. Gill,
Edward M. Schwarz
Publication year - 2020
Publication title -
plos pathogens
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.719
H-Index - 206
eISSN - 1553-7374
pISSN - 1553-7366
DOI - 10.1371/journal.ppat.1008988
Subject(s) - staphylococcus aureus , microbiology and biotechnology , osteomyelitis , penicillin binding proteins , vancomycin , in vivo , antibiotics , staphylococcal infections , biology , penicillin , chemistry , bacteria , immunology , genetics
Staphylococcus aureus infection of bone is challenging to treat because it colonizes the osteocyte lacuno-canalicular network (OLCN) of cortical bone. To elucidate factors involved in OLCN invasion and identify novel drug targets, we completed a hypothesis-driven screen of 24 S . aureus transposon insertion mutant strains for their ability to propagate through 0.5 μm-sized pores in the Micro fluidic Si licon M embrane C analicular A rrays (μSiM-CA), developed to model S . aureus invasion of the OLCN. This screen identified the uncanonical S . aureus transpeptidase, penicillin binding protein 4 (PBP4), as a necessary gene for S . aureus deformation and propagation through nanopores. In vivo studies revealed that Δpbp4 infected tibiae treated with vancomycin showed a significant 12-fold reduction in bacterial load compared to WT infected tibiae treated with vancomycin (p<0.05). Additionally, Δpbp4 infected tibiae displayed a remarkable decrease in pathogenic bone-loss at the implant site with and without vancomycin therapy. Most importantly, Δpbp4 S . aureus failed to invade and colonize the OLCN despite high bacterial loads on the implant and in adjacent tissues. Together, these results demonstrate that PBP4 is required for S . aureus colonization of the OLCN and suggest that inhibitors may be synergistic with standard of care antibiotics ineffective against bacteria within the OLCN.