scholarly journals Role of Penicillin‐Binding Proteins in Resistance ofBacteroides fragilisGroup Species to β‐Lactam Drugs

1997 ◽  
Vol 25 (s2) ◽  
pp. S270-S271 ◽  
Author(s):  
Maria Hedberg ◽  
Elisabeth Nagy ◽  
C. E. Nord
Keyword(s):  
Binding Proteins ◽  
Penicillin Binding Proteins

scholarly journals Role of Penicillin-Binding Proteins in the Initiation of the AmpC β-Lactamase Expression inEnterobacter cloacae

2000 ◽  
Vol 44 (1) ◽  
pp. 169-172 ◽  
Author(s):  
Dieter Pfeifle ◽  
Eva Janas ◽  
Bernd Wiedemann
Keyword(s):  
Escherichia Coli ◽  
Binding Proteins ◽  
Penicillin Binding Proteins

ABSTRACT Penicillin-binding proteins (PBPs) are involved in the regulation of β-lactamase expression by determining the level of anhydromuramylpeptides in the periplasmatic space. It was hypothesized that one or more PBPs act as a sensor in the β-lactamase induction pathway. We have performed induction studies with Escherichia coli mutants lacking one to four PBPs withdd-carboxypeptidase activity. Therefore, we conclude that a strong β-lactamase inducer must inhibit alldd-carboxypeptidases as well as the essential PBPs 1a, 1b, and/or 2.

Role of penicillin-binding proteins in the viability, morphology, stress tolerance and pathogenicity of Clavibacter michiganensis

2020 ◽  
Author(s):  
Xing Chen ◽  
Kaihong Bai ◽  
Qingyang Lyu ◽  
Na Jiang ◽  
Jianqiang Li ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Protective Role ◽  
Vbnc State ◽  
Clavibacter Michiganensis ◽  
Penicillin Binding Proteins ◽  
Class B ◽  
Increased Sensitivity ◽  
Type C ◽  
Adverse Environmental Conditions

Previous research has shown that penicillin-binding proteins (PBPs), enzymes involved in peptidoglycan (PG) assembly, could play an important role during the induction of viable but non-culturable (VBNC) state, which allows non-spore forming bacteria to survive adverse environmental conditions. The current study found that C. michiganensis has a total of seven PBP proteins. Mutant analysis indicated that deletion of either of the class B PBPs was lethal, and that the class A PBP, PBPC, had an important role in PG synthesis, with the ΔpbpC mutant having an altered cellular morphology that resulted in longer cells that were swollen at one end, and had thinner cell walls. The ΔpbpC mutant was also found to produce mucoid colonies in solid culture and a lower final cell titer in liquid medium, as well as having increased sensitivity to osmotic stress and lysozyme treatment, and surprisingly increased pathogenicity. The double mutant, ΔdacB/ΔpbpE also had a slightly altered phenotype resulting in longer cells. Further analysis revealed that both mutants had increased sensitivity to copper, which resulted in quicker induction into the VBNC state. However, only the ΔpbpC mutant had significantly reduced survivorship in the VBNC state. The study also confirmed the VBNC state significantly improved the survivorship of wild-type C. michiganensis cells in response to environmental stresses, and systemically demonstrated the protective role of the VBNC state in C. michiganensis, which is an important finding regarding its epidemiology, and has serious implications for disease management.

Investigations on the role of CH…O interactions and its impact on stability and specificity of penicillin binding proteins

2015 ◽  
Vol 65 ◽  
pp. 85-92 ◽  
Author(s):  
P. Lavanya ◽  
Sudha Ramaiah ◽  
Harpeet Singh ◽  
Renu Bahadur ◽  
Anand Anbarasu
Keyword(s):  
Binding Proteins ◽  
Penicillin Binding Proteins

scholarly journals Role of AmpD, OprF and penicillin-binding proteins in β-lactam resistance in clinical isolates of Pseudomonas aeruginosa

2007 ◽  
Vol 56 (6) ◽  
pp. 809-814 ◽  
Author(s):  
Simona Bratu ◽  
David Landman ◽  
Jyoti Gupta ◽  
John Quale
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Binding Proteins ◽  
Clinical Isolates ◽  
Rt Pcr ◽  
Penicillin Binding Proteins ◽  
Genomic Deletions ◽  
Cephalosporin Resistance ◽  
Outer Membrane Permeability

In this study, the mechanisms leading to increased chromosomal AmpC β-lactamase expression and the contributory roles of the outer-membrane protein OprF and penicillin-binding proteins were analysed in 33 characterized clinical isolates of Pseudomonas aeruginosa. The genes ampD and ampE were analysed by PCR and DNA sequencing. Expression of the gene oprF was assessed using real-time RT-PCR, and penicillin-binding proteins were analysed using a chemiluminescence assay. Several of the isolates with increased ampC expression had major deletions affecting ampD, although in some isolates the mechanism of increased ampC expression could not be ascertained. Occasional isolates had increased expression of both ampC and oprF but remained susceptible to cephalosporins, suggesting that increased β-lactamase activity could not offset increased outer-membrane permeability. There were no discernible changes in penicillin-binding proteins. Genomic deletions in ampD were observed in selected clinical isolates of P. aeruginosa with increased expression of the AmpC β-lactamase. For some isolates, cephalosporin resistance was dependent upon the interplay of ampC and oprF expression.

scholarly journals Role of Pseudomonas aeruginosa Low-Molecular-Mass Penicillin-Binding Proteins in AmpC Expression, β-Lactam Resistance, and Peptidoglycan Structure

2015 ◽  
Vol 59 (7) ◽  
pp. 3925-3934 ◽  
Author(s):  
Alaa Ropy ◽  
Gabriel Cabot ◽  
Irina Sánchez-Diener ◽  
Cristian Aguilera ◽  
Bartolome Moya ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Molecular Mass ◽  
Binding Proteins ◽  
Wild Type ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
Peptidoglycan Structure ◽  
The Impact ◽  
Pao1 Strain

ABSTRACTThis study aimed to characterize the role ofPseudomonas aeruginosalow-molecular-mass penicillin-binding proteins (LMM PBPs), namely, PBP4 (DacB), PBP5 (DacC), and PBP7 (PbpG), in peptidoglycan composition, β-lactam resistance, andampCregulation. For this purpose, we constructed all single and multiple mutants ofdacB,dacC,pbpG, andampCfrom the wild-typeP. aeruginosaPAO1 strain. Peptidoglycan composition was determined by high-performance liquid chromatography (HPLC),ampCexpression by reverse transcription-PCR (RT-PCR), PBP patterns by a Bocillin FL-binding test, and antimicrobial susceptibility by MIC testing for a panel of β-lactams. Microscopy and growth rate analyses revealed no apparent major morphological changes for any of the mutants compared to the wild-type PAO1 strain. Of the single mutants, onlydacCmutation led to significantly increased pentapeptide levels, showing that PBP5 is the majordd-carboxypeptidase inP. aeruginosa. Moreover, our results indicate that PBP4 and PBP7 play a significant role asdd-carboxypeptidase only if PBP5 is absent, and theirdd-endopeptidase activity is also inferred. As expected, the inactivation of PBP4 led to a significant increase inampCexpression (around 50-fold), but, remarkably, the sequential inactivation of the three LMM PBPs produced a much greater increase (1,000-fold), which correlated with peptidoglycan pentapeptide levels. Finally, the β-lactam susceptibility profiles of the LMM PBP mutants correlated well with theampCexpression data. However, the inactivation ofampCin these mutants also evidenced a role of LMM PBPs, especially PBP5, in intrinsic β-lactam resistance. In summary, in addition to assessing the effect ofP. aeruginosaLMM PBPs on peptidoglycan structure for the first time, we obtained results that represent a step forward in understanding the impact of these PBPs on β-lactam resistance, apparently driven by the interplay between their roles in AmpC induction, β-lactam trapping, anddd-carboxypeptidase/β-lactamase activity.

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