scholarly journals Overproduction of a penicillin-binding protein is not the only mechanism of penicillin resistance in Enterococcus faecium.

1992 ◽  
Vol 36 (4) ◽  
pp. 783-787 ◽  
Author(s):  
I Klare ◽  
A C Rodloff ◽  
J Wagner ◽  
W Witte ◽  
R Hakenbeck
Keyword(s):  
Enterococcus Faecium ◽  
Binding Protein ◽  
Penicillin Resistance ◽  
Penicillin Binding Protein

scholarly journals The VanYD DD-carboxypeptidase of Enterococcus faecium BM4339 is a penicillin-binding protein

Microbiology ◽  
2001 ◽  
Vol 147 (9) ◽  
pp. 2571-2578 ◽  
Author(s):  
Peter E Reynolds ◽  
O. Herman Ambur ◽  
Barbara Casadewall ◽  
Patrice Courvalin
Keyword(s):  
Enterococcus Faecium ◽  
Binding Protein ◽  
Penicillin Binding Protein

scholarly journals Identification and Characterization of the Penicillin-Binding Protein 2a of Streptococcus pneumoniae and Its Possible Role in Resistance to β-Lactam Antibiotics

2000 ◽  
Vol 44 (6) ◽  
pp. 1745-1748 ◽  
Author(s):  
Genshi Zhao ◽  
Timothy I. Meier ◽  
Joann Hoskins ◽  
Kelly A. McAllister
Keyword(s):  
Streptococcus Pneumoniae ◽  
Binding Protein ◽  
Penicillin Resistance ◽  
Penicillin Binding Protein ◽  
Insertional Mutant ◽  
Identification And Characterization

ABSTRACT To further understand the role of penicillin-binding protein 2a (PBP 2a) of Streptococcus pneumoniae in penicillin resistance, we confirmed the identity of the protein as PBP 2a. The PBP 2a protein migrated electrophoretically to a position corresponding to that of PBP 2x, PBP 2a, and PBP 2b of S. pneumoniae and was absent in a pbp2ainsertional mutant of S. pneumoniae. We found that the affinities of PBP 2a for penicillins were lower than for cephalosporins and a carbapenem. When compared with other S. pneumoniae PBPs, PBP 2a exhibited lower affinities for β-lactam antibiotics, especially penicillins. Therefore, PBP 2a is a low-affinity PBP for β-lactam antibiotics in S. pneumoniae.

scholarly journals Differential Penicillin-Binding Protein 5 (PBP5) Levels in the Enterococcus faecium Clades with Different Levels of Ampicillin Resistance

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Maria Camila Montealegre ◽  
Jung Hyeob Roh ◽  
Meredith Rae ◽  
Milya G. Davlieva ◽  
Kavindra V. Singh ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Binding Protein ◽  
Mrna Levels ◽  
Nucleotide Polymorphisms ◽  
Penicillin Binding Protein ◽  
Ampicillin Resistance ◽  
Content Type ◽  
Protein Levels ◽  
Clade B ◽  
Wide Range

ABSTRACT Ampicillin resistance in Enterococcus faecium is a serious concern worldwide, complicating the treatment of E. faecium infections. Penicillin-binding protein 5 (PBP5) is considered the main ampicillin resistance determinant in E. faecium. The three known E. faecium clades showed sequence variations in the pbp5 gene that are associated with their ampicillin resistance phenotype; however, these changes alone do not explain the array of resistance levels observed among E. faecium clinical strains. We aimed to determine if the levels of PBP5 are differentially regulated between the E. faecium clades, with the hypothesis that variations in PBP5 levels could help account for the spectrum of ampicillin MICs seen in E. faecium. We studied pbp5 mRNA levels and PBP5 protein levels as well as the genetic environment upstream of pbp5 in 16 E. faecium strains that belong to the different E. faecium clades and for which the ampicillin MICs covered a wide range. Our results found that pbp5 and PBP5 levels are increased in subclade A1 and A2 ampicillin-resistant strains compared to those in clade B and subclade A2 ampicillin-susceptible strains. Furthermore, we found evidence of major clade-associated rearrangements in the region upstream of pbp5, including large DNA fragment insertions, deletions, and single nucleotide polymorphisms, that may be associated with the differential regulation of PBP5 levels between the E. faecium clades. Overall, these findings highlight the contribution of the clade background to the regulation of PBP5 abundance and point to differences in the region upstream of pbp5 as likely contributors to the differential expression of ampicillin resistance.

scholarly journals Penicillin-Binding Protein Gene Alterations in Streptococcus uberis Isolates Presenting Decreased Susceptibility to Penicillin

2010 ◽  
Vol 54 (3) ◽  
pp. 1140-1145 ◽  
Author(s):  
Marisa Haenni ◽  
Laure Galofaro ◽  
Mathilde Ythier ◽  
Marlyse Giddey ◽  
Paul Majcherczyk ◽  
...  
Keyword(s):  
Binding Protein ◽  
Bovine Mastitis ◽  
Penicillin Resistance ◽  
Penicillin G ◽  
Penicillin Binding Protein ◽  
Resistance Development ◽  
Streptococcus Uberis ◽  
Binding Protein Gene ◽  
The One ◽  
Gene Alterations

ABSTRACT Streptococcus uberis is an environmental pathogen commonly causing bovine mastitis, an infection that is generally treated with penicillin G. No field case of true penicillin-resistant S. uberis (MIC > 16 mg/liter) has been described yet, but isolates presenting decreased susceptibility (MIC of 0.25 to 0.5 mg/liter) to this drug are regularly reported to our laboratory. In this study, we demonstrated that S. uberis can readily develop penicillin resistance in laboratory-evolved mutants. The molecular mechanism of resistance (acquisition of mutations in penicillin-binding protein 1A [PBP1A], PBP2B, and PBP2X) was generally similar to that of all other penicillin-resistant streptococci described so far. In addition, it was also specific to S. uberis in that independent resistant mutants carried a unique set of seven consensus mutations, of which only one (Q554E in PBP2X) was commonly found in other streptococci. In parallel, independent isolates from bovine mastitis with different geographical origins (France, Holland, and Switzerland) and presenting a decreased susceptibility to penicillin were characterized. No mosaic PBPs were detected, but they all presented mutations identical to the one found in the laboratory-evolved mutants. This indicates that penicillin resistance development in S. uberis might follow a stringent pathway that would explain, in addition to the ecological niche of this pathogen, why naturally occurring resistances are still rare. In addition, this study shows that there is a reservoir of mutated PBPs in animals, which might be exchanged with other streptococci, such as Streptococcus agalactiae, that could potentially be transmitted to humans.

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