TY - JOUR

T1 - A Staphylococcus aureus clpX Mutant Used as a Unique Screening Tool to Identify Cell Wall Synthesis Inhibitors that Reverse β-Lactam Resistance in MRSA

AU - Bæk, Kristoffer T.

AU - Jensen, Camilla

AU - Farha, Maya A.

AU - Nielsen, Tobias K.

AU - Paknejadi, Ervin

AU - Mebus, Viktor H.

AU - Vestergaard, Martin

AU - Brown, Eric D.

AU - Frees, Dorte

N1 - Publisher Copyright: © Copyright © 2021 Bæk, Jensen, Farha, Nielsen, Paknejadi, Mebus, Vestergaard, Brown and Frees.

PY - 2021

Y1 - 2021

N2 - Staphylococcus aureus is a leading cause of bacterial infections world-wide. Staphylococcal infections are preferentially treated with β-lactam antibiotics, however, methicillin-resistant S. aureus (MRSA) strains have acquired resistance to this superior class of antibiotics. We have developed a growth-based, high-throughput screening approach that directly identifies cell wall synthesis inhibitors capable of reversing β-lactam resistance in MRSA. The screen is based on the finding that S. aureus mutants lacking the ClpX chaperone grow very poorly at 30°C unless specific steps in teichoic acid synthesis or penicillin binding protein (PBP) activity are inhibited. This property allowed us to exploit the S. aureus clpX mutant as a unique screening tool to rapidly identify biologically active compounds that target cell wall synthesis. We tested a library of ∼50,000 small chemical compounds and searched for compounds that inhibited growth of the wild type while stimulating growth of the clpX mutant. Fifty-eight compounds met these screening criteria, and preliminary tests of 10 compounds identified seven compounds that reverse β-lactam resistance of MRSA as expected for inhibitors of teichoic acid synthesis. The hit compounds are therefore promising candidates for further development as novel combination agents to restore β-lactam efficacy against MRSA.

AB - Staphylococcus aureus is a leading cause of bacterial infections world-wide. Staphylococcal infections are preferentially treated with β-lactam antibiotics, however, methicillin-resistant S. aureus (MRSA) strains have acquired resistance to this superior class of antibiotics. We have developed a growth-based, high-throughput screening approach that directly identifies cell wall synthesis inhibitors capable of reversing β-lactam resistance in MRSA. The screen is based on the finding that S. aureus mutants lacking the ClpX chaperone grow very poorly at 30°C unless specific steps in teichoic acid synthesis or penicillin binding protein (PBP) activity are inhibited. This property allowed us to exploit the S. aureus clpX mutant as a unique screening tool to rapidly identify biologically active compounds that target cell wall synthesis. We tested a library of ∼50,000 small chemical compounds and searched for compounds that inhibited growth of the wild type while stimulating growth of the clpX mutant. Fifty-eight compounds met these screening criteria, and preliminary tests of 10 compounds identified seven compounds that reverse β-lactam resistance of MRSA as expected for inhibitors of teichoic acid synthesis. The hit compounds are therefore promising candidates for further development as novel combination agents to restore β-lactam efficacy against MRSA.

KW - cell wall synthesis

KW - ClpX

KW - high-throughput screen

KW - pathway-directed drug discovery

KW - Staphylococcus aureus

KW - teichoic acid inhibitors

KW - β-lactam antibiotics

U2 - 10.3389/fmolb.2021.691569

DO - 10.3389/fmolb.2021.691569

M3 - Journal article

C2 - 34150853

AN - SCOPUS:85108166207

VL - 8

JO - Frontiers in Molecular Biosciences

JF - Frontiers in Molecular Biosciences

SN - 2296-889X

M1 - 691569

ER -