Identification of Penicillin Binding Protein 4 (PBP4) as a critical factor for Staphylococcus aureus bone invasion during osteomyelitis in mice

• DOI: 10.1371/journal.ppat.1008988
• Publication Date: 2020-10-22T17:52:57Z
• Authors: Elysia A. Masters; Karen L. de Mesy ...; Ann Lindley Gill; Stephanie P. Hao; Chad A. Galloway; Alec T. Salminen; Diamond R. Guy; James L. McGrath; Hani A. Awad; Steven R. Gill; Edward M. Schwarz
• Keywords: Penicillin binding proteins

Staphylococcus aureus infection of bone is challenging to treat because it colonizes the osteocyte lacuno-canalicular network (OLCN) cortical bone. To elucidate factors involved in OLCN invasion and identify novel drug targets, we completed a hypothesis-driven screen 24 S. transposon insertion mutant strains for their ability propagate through 0.5 μm-sized pores Microfluidic Silicon Membrane Canalicular Arrays (μSiM-CA), developed model OLCN. This identified uncanonical transpeptidase, penicillin binding protein 4 (PBP4), as necessary gene deformation propagation nanopores. In vivo studies revealed that Δpbp4 infected tibiae treated with vancomycin showed significant 12-fold reduction bacterial load compared WT (p<0.05). Additionally, displayed remarkable decrease pathogenic bone-loss at implant site without therapy. Most importantly, failed invade colonize despite high loads on adjacent tissues. Together, these results demonstrate PBP4 required colonization suggest inhibitors may be synergistic standard care antibiotics ineffective against bacteria within