scholarly journals Dual β-lactam combination therapy for multi-drug resistant Pseudomonas aeruginosa infection: enhanced efficacy in vivo and comparison with monotherapies of penicillin-binding protein inhibition

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thanyaluck Siriyong ◽  
Rachael M. Murray ◽  
Lucy E. Bidgood ◽  
Simon A. Young ◽  
Florence Wright ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Combination Therapy ◽  
Binding Protein ◽  
Drug Resistant ◽  
Penicillin Binding Protein ◽  
Protein Inhibition ◽  
Pseudomonas Aeruginosa Infection

scholarly journals Pan-β-Lactam Resistance Development in Pseudomonas aeruginosa Clinical Strains: Molecular Mechanisms, Penicillin-Binding Protein Profiles, and Binding Affinities

2012 ◽  
Vol 56 (9) ◽  
pp. 4771-4778 ◽  
Author(s):  
Bartolomé Moyá ◽  
Alejandro Beceiro ◽  
Gabriel Cabot ◽  
Carlos Juan ◽  
Laura Zamorano ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Binding Protein ◽  
Efflux Pumps ◽  
Binding Affinities ◽  
Penicillin Binding Protein ◽  
Content Type ◽  
Reverse Transcription Pcr

ABSTRACTWe investigated the mechanisms leading toPseudomonas aeruginosapan-β-lactam resistance (PBLR) development during the treatment of nosocomial infections, with a particular focus on the modification of penicillin-binding protein (PBP) profiles and imipenem, ceftazidime, and ceftolozane (former CXA-101) PBP binding affinities. For this purpose, six clonally related pairs of sequential susceptible-PBLR isolates were studied. The presence ofoprD,ampD, anddacBmutations was explored by PCR followed by sequencing and the expression ofampCand efflux pump genes by real-time reverse transcription-PCR. The fluorescent penicillin Bocillin FL was used to determine PBP profiles in membrane preparations from all pairs, and 50% inhibitory concentrations (IC50s) of ceftolozane, ceftazidime, and imipenem were analyzed in 3 of them. Although a certain increase was noted (0 to 5 2-fold dilutions), the MICs of ceftolozane were ≤4 μg/ml in all PBLR isolates. All 6 PBLR isolates lacked OprD and overexpressedampCand one or several efflux pumps, particularlymexBand/ormexY. Additionally, 5 of them showed modified PBP profiles, including a modified pattern (n= 1) or diminished expression (n= 1) of PBP1a and a lack of PBP4 expression (n= 4), which correlated with AmpC overexpression driven bydacBmutation. Analysis of the essential PBP IC50s revealed significant variation of PBP1a/b binding affinities, both within each susceptible-PBLR pair and across the different pairs. Moreover, despite the absence of significant differences in gene expression or sequence, a clear tendency toward increased PBP2 (imipenem) and PBP3 (ceftazidime, ceftolozane, imipenem) IC50s was noted in PBLR isolates. Thus, our results suggest that in addition to AmpC, efflux pumps, and OprD, the modification of PBP patterns appears to play a role in thein vivoemergence of PBLR strains, which still conserve certain susceptibility to the new antipseudomonal cephalosporin ceftolozane.

scholarly journals WS04.2 Azithromycin treatment of Pseudomonas aeruginosa infection potentiates IgY pulmonary protection in vivo

2018 ◽  
Vol 17 ◽  
pp. S7-S8
Author(s):  
K. Thomsen ◽  
S. Larsen ◽  
L. Christophersen ◽  
C. Lerche ◽  
N. Høiby ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Aeruginosa Infection ◽  
Pulmonary Protection

scholarly journals Overproduction of Penicillin-Binding Protein 2 and Its Inactive Variants Causes Morphological Changes and Lysis in Escherichia coli

2007 ◽  
Vol 189 (14) ◽  
pp. 4975-4983 ◽  
Author(s):  
Blaine A. Legaree ◽  
Calvin B. Adams ◽  
Anthony J. Clarke
Keyword(s):  
Escherichia Coli ◽  
Signal Sequence ◽  
Morphological Changes ◽  
Binding Protein ◽  
Penicillin Binding Protein ◽  
Prolonged Incubation ◽  
Lytic Transglycosylases ◽  
E Coli ◽  
Derivatives Of

ABSTRACT Penicillin-binding protein 2 (PBP 2) has long been known to be essential for rod-shaped morphology in gram-negative bacteria, including Escherichia coli and Pseudomonas aeruginosa. In the course of earlier studies with P. aeruginosa PBP 2, we observed that E. coli was sensitive to the overexpression of its gene, pbpA. In this study, we examined E. coli overproducing both P. aeruginosa and E. coli PBP 2. Growth of cells entered a stationary phase soon after induction of gene expression, and cells began to lyse upon prolonged incubation. Concomitant with the growth retardation, cells were observed to have changed morphologically from typical rods into enlarged spheres. Inactive derivatives of the PBP 2s were engineered, involving site-specific replacement of their catalytic Ser residues with Ala in their transpeptidase module. Overproduction of these inactive PBPs resulted in identical effects. Likewise, overproduction of PBP 2 derivatives possessing only their N-terminal non-penicillin-binding module (i.e., lacking their C-terminal transpeptidase module) produced similar effects. However, E. coli overproducing engineered derivatives of PBP 2 lacking their noncleavable, N-terminal signal sequence and membrane anchor were found to grow and divide at the same rate as control cells. The morphological effects and lysis were also eliminated entirely when overproduction of PBP 2 and variants was conducted with E. coli MHD79, a strain lacking six lytic transglycosylases. A possible interaction between the N-terminal domain of PBP 2 and lytic transglycosylases in vivo through the formation of multienzyme complexes is discussed.

scholarly journals Structural Insights into Ceftobiprole Inhibition of Pseudomonas aeruginosa Penicillin-Binding Protein 3

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Vijay Kumar ◽  
Christie Tang ◽  
Christopher R. Bethel ◽  
Krisztina M. Papp-Wallace ◽  
Jacob Wyatt ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Binding Protein ◽  
Covalent Bond ◽  
Penicillin Binding Protein ◽  
Content Type ◽  
Cephalosporin Antibiotic ◽  
Structural Insights ◽  
Fine Tune ◽  
Advanced Generation

ABSTRACT Ceftobiprole is an advanced-generation broad-spectrum cephalosporin antibiotic with potent and rapid bactericidal activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, as well as susceptible Gram-negative pathogens, including Pseudomonas sp. pathogens. In the case of Pseudomonas aeruginosa, ceftobiprole acts by inhibiting P. aeruginosa penicillin-binding protein 3 (PBP3). Structural studies were pursued to elucidate the molecular details of this PBP inhibition. The crystal structure of the His-tagged PBP3-ceftobiprole complex revealed a covalent bond between the ligand and the catalytic residue S294. Ceftobiprole binding leads to large active site changes near binding sites for the pyrrolidinone and pyrrolidine rings. The S528 to L536 region adopts a conformation previously not observed in PBP3, including partial unwinding of the α11 helix. These molecular insights can lead to a deeper understanding of β-lactam-PBP interactions that result in major changes in protein structure, as well as suggesting how to fine-tune current inhibitors and to develop novel inhibitors of this PBP.

Substrate specificity of the high-affinity glucose transport system of Pseudomonas aeruginosa

1993 ◽  
Vol 39 (7) ◽  
pp. 722-725 ◽  
Author(s):  
John L. Wylie ◽  
Elizabeth A. Worobec
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Glucose Transport ◽  
Transport System ◽  
Binding Protein ◽  
High Affinity ◽  
Glucose Binding ◽  
Glucose Transport System ◽  
Glucose Binding Protein

Specificity of the high-affinity glucose transport system of Pseudomonas aeruginosa was examined. At a concentration of [14C]glucose near the Vmax of the system, inhibition by maltose, galactose, and xylose was detected. This inhibition is similar to that detected in earlier in vivo studies and correlates with the known specificity of OprB, a glucose-specific porin of P. aeruginosa. At a level of [14C]glucose 100 times lower, only unlabelled glucose inhibited uptake to any extent. This matches the known in vitro specificity of the periplasmic glucose binding protein. These findings were used to explain the discrepancy between earlier in vivo and in vitro results reported in the literature.Key words: Pseudomonas aeruginosa, glucose transport, OprB, glucose binding protein.

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