PBP 4 Mediates High-Level Resistance to New-Generation Cephalosporins in Staphylococcus aureus

Chan, Liana C.; Gilbert, Aubre; Basuino, Li; Costa, Thaina Miranda da; Hamilton, Stephanie M.; Santos, Katia Rn Dos; Chambers, Henry F.; Chatterjee, Som S.

doi:10.1128/aac.00358-16

Cited by 37 publications

(51 citation statements)

References 43 publications

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“…We have previously shown that passage of the COLnex strain in ceftobiprole (generating strain CRB) resulted in resistance to both ceftobiprole and ceftaroline, with the MICs being 128 g/ml and 64 g/ml, respectively ( Table 1), and that resistance was associated with two amino acid substitutions, E183A and F241R, in PBP4 (3,4). Resistance was also associated with a markedly increased amount of PBP4 in whole-cell lysates and membrane proteins of CRB compared with the amount in COLnex ( Fig.…”

Section: Resultsmentioning

confidence: 99%

High-Level Resistance of Staphylococcus aureus to β-Lactam Antibiotics Mediated by Penicillin-Binding Protein 4 (PBP4)

Hamilton

Alexander

Choo

et al. 2017

Antimicrob Agents Chemother

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Penicillin-binding protein 4 (PBP4), a nonessential, low-molecular-weight penicillin-binding protein of Staphylococcus aureus, has been implicated in low-level resistance to ␤-lactam antibiotics, although the mechanism is unknown. Mutations in PBP4 and its promoter were identified in a laboratory-generated mutant strain, CRB, which expresses high-level resistance to ␤-lactams, including resistance to the newgeneration cephalosporins active against methicillin-resistant strains of S. aureus. These mutations did not appreciably alter the ␤-lactam antibiotic binding affinity of purified recombinant mutant PBP4 compared to that of wild-type PBP4. Compared to the susceptible parent strain, COLnex, the CRB strain produces a highly crosslinked cell wall peptidoglycan, indicative of increased transpeptidase activity. The pbp4 promoter mutation of CRB was associated with greatly increased amounts of PBP4 in membranes compared to those in the COLnex parent. Replacement of the native promoter of COLnex with the mutant promoter of CRB resulted in increased amounts of PBP4 in membranes and a highly cross-linked cell wall. PBP4 can be repurposed to provide essential transpeptidase activity in vivo and confer high-level resistance to ␤-lactam antibiotics, such as ceftobiprole and ceftaroline.

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Section: Resultsmentioning

confidence: 99%

High-Level Resistance of Staphylococcus aureus to β-Lactam Antibiotics Mediated by Penicillin-Binding Protein 4 (PBP4)

Hamilton

Alexander

Choo

et al. 2017

Antimicrob Agents Chemother

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“…Resistance to ␤-lactam antibiotics seen in MRSA is especially serious as they remain the most widely prescribed class globally, typically having a favorable safety profile and being relatively affordable and accessible. Although broad-spectrum MRSA resistance to ␤-lactam antibiotics has long been attributed to impaired acylation of the mecA gene product, penicillin-binding protein 2a (PBP2a) (2), recent evidence shows penicillin-binding protein 4 (PBP4), a low-molecular-weight monofunctional transpeptidase, can facilitate antibiotic resistance independently of PBP2a (3)(4)(5)(6)(7)(8)(9). It has been previously demonstrated that the only essential penicillinbinding proteins (PBPs) in S. aureus are the monofunctional highmolecular-weight transpeptidase, PBP1, and the bifunctional PBP2 (glycopolymerase/transpeptidase) (10).…”

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confidence: 99%

Structural and kinetic analyses of penicillin-binding protein 4 (PBP4)-mediated antibiotic resistance in Staphylococcus aureus

Alexander¹,

Chatterjee

Hamilton

et al. 2018

Journal of Biological Chemistry

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Edited by Chris Whitfield Methicillin-resistant Staphylococcus aureus (MRSA) causes serious community-acquired and nosocomial infections worldwide. MRSA strains are resistant to a variety of antibiotics, including the classic penicillin and cephalosporin classes of ␤-lactams, making them intractable to treatment. Although ␤-lactam resistance in MRSA has been ascribed to the acquisition and activity of penicillin-binding protein 2a (PBP2a, encoded by mecA), it has recently been observed that resistance can also be mediated by penicillin-binding protein 4 (PBP4). Previously, we have shown that broad-spectrum ␤-lactam resistance can arise following serial passaging of a mecA-negative COL strain of S. aureus, creating the CRB strain. This strain has two missense mutations in pbp4 and a mutation in the pbp4 promoter, both of which play an instrumental role in ␤-lactam resistance. To better understand PBP4's role in resistance, here we have characterized its kinetics and structure with clinically relevant ␤-lactam antibiotics. We present the first crystallographic PBP4 structures of apo and acyl-enzyme intermediate forms complexed with three late-generation ␤-lactam antibiotics: ceftobiprole, ceftaroline, and nafcillin. In parallel, we characterized the structural and kinetic effects of the PBP4 mutations present in the CRB strain. Localized within the transpeptidase active-site cleft, the two substitutions appear to have different effects depending on the drug. With ceftobiprole, the missense mutations impaired the K m value 150-fold, decreasing the proportion of inhibited PBP4. However, ceftaroline resistance appeared to be mediated by other factors, possibly including mutation of the pbp4 promoter. Our findings provide evidence that S. aureus CRB has at least two PBP4-mediated resistance mechanisms.

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“…Analogous to alternative PBP usage in methicillin resistant Staphylococcus aureus (55,56), we find a key consequence of environment-driven plasticity in E. coli cell wall metabolism is intrinsic resistance to β-lactam antibiotics with a narrow target specificity. The most commonly prescribed class antibiotics, β-lactam antibiotics are frequently used to treat E. coli infections, including in treatment of urinary tract infections.…”

Section: Discussionmentioning

confidence: 84%

Plasticity in Escherichia coli cell wall metabolism promotes fitness and mediates intrinsic antibiotic resistance across environmental conditions

Mueller

Levin²

2018

Preprint

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Although the peptidoglycan cell wall is an essential structural and morphological feature of most bacterial cells, the extracytoplasmic enzymes involved in its synthesis are frequently dispensable under standard culture conditions. By modulating a single growth parameter—extracellular pH—we discovered a subset of these so-called “redundant” enzymes in Escherichia coli are required for maximal fitness across pH environments. Among these pH specialists are the class A penicillin binding proteins PBP1 a and PBP1 b; defects in these enzymes attenuate growth in alkaline and acidic conditions, respectively. Genetic, biochemical, and cytological studies demonstrate that synthase activity is required for cell wall integrity across a wide pH range, and differential activity across pH environments significantly alters intrinsic resistance to cell wall active antibiotics. Together, our findings reveal previously thought to be redundant enzymes are instead specialized for distinct environmental niches, thereby ensuring robust growth and cell wall integrity in a wide range of conditions.

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PBP 4 Mediates High-Level Resistance to New-Generation Cephalosporins in Staphylococcus aureus

Cited by 37 publications

References 43 publications

High-Level Resistance of Staphylococcus aureus to β-Lactam Antibiotics Mediated by Penicillin-Binding Protein 4 (PBP4)

High-Level Resistance of Staphylococcus aureus to β-Lactam Antibiotics Mediated by Penicillin-Binding Protein 4 (PBP4)

Structural and kinetic analyses of penicillin-binding protein 4 (PBP4)-mediated antibiotic resistance in Staphylococcus aureus

Plasticity in Escherichia coli cell wall metabolism promotes fitness and mediates intrinsic antibiotic resistance across environmental conditions

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