The Penicillin‐Binding Proteins in <i>Streptococcus faecalis</i> ATCC 9790

Coyette, Jacques; Ghuysen, Jean‐Marie; Fontana, Roberta

doi:10.1111/j.1432-1033.1980.tb04886.x

Cited by 52 publications

(45 citation statements)

References 14 publications

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“…This finding demonstrates that in wild-type S . faecium different PBPs are essential in fast growing cells and in cells growing at a reduced rate and indicates that a PBP does not necessarily fulfil the same role under all conditions but that its function depends on the physiological status of the cells, as previously suggested (Fontana et al, 1983~). Such a finding has implications for understanding the functions of PBPs in cell physiology and the way in which their activity is regulated.…”

Section: P C a N E P A R I A N D Others Discussionmentioning

confidence: 66%

In Streptococcus faecium Penicillin-binding Protein 5 Alone Is Sufficient for Growth at Sub-maximal But Not at Maximal Rate

et al. 1986

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Section: P C a N E P A R I A N D Others Discussionmentioning

confidence: 66%

In Streptococcus faecium Penicillin-binding Protein 5 Alone Is Sufficient for Growth at Sub-maximal But Not at Maximal Rate

et al. 1986

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“…Other selective additives, such as 5-bromo-4-chloro-3-indolyl-␤-D-galactopyranoside (X-Gal) (40 g/ml) and isopropyl-␤-D-thiogalactopyrano- side (IPTG) (7 g/ml) (both obtained from Immunosource, Zoersel-Halle, Belgium), were used or added to the media as required. MICs were determined in 1 ml of brain heart infusion broth in 24-well culture plates in at least three independent experiments, essentially as previously described (9).…”

Section: Methodsmentioning

confidence: 99%

Redefining the Role of psr in β-Lactam Resistance and Cell Autolysis of Enterococcus hirae

et al. 2003

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The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the ␤-lactam resistance, growth, and cell autolysis of wild-type strain ATCC 9790 and resistant strain R40 of Enterococcus hirae was investigated by disruption or substitution of the corresponding pbp5 and psr genes by Campbell-type recombination. The resulting modifications were confirmed by hybridization and PCR. The low susceptibility of E. hirae to ␤-lactams was confirmed to be largely dependent on the presence of PBP5. However, against all expectations, inactivation of psr in ATCC 9790 or complementation of R40 cells with psr did not modify the susceptibility to benzylpenicillin or the growth and cell autolysis rates. These results indicated that the psr gene does not seem to be involved in the regulation of PBP5 synthesis and consequently in ␤-lactam resistance or in the regulation of cell autolysis in E. hirae.The natural low susceptibility of enterococci to ␤-lactams is due to a low-affinity penicillin-binding protein (PBP) that is overproduced in moderately resistant laboratory mutants and some clinical strains (16,17,35,45). Highly resistant clinical strains generally do not overproduce this low-affinity PBP but modify its primary structure to further reduce its binding capacity (21,24,35,45). Conversely, when the low-affinity PBP is not synthesized, the cells become highly susceptible to benzylpenicillin (PenG) (18).Sequencing of the enterococcal genes encoding low-affinity PBPs showed that these proteins are relatively similar (ϳ75 kDa) (13,14,33,35,45). Including PBP2Ј of methicillin-resistant staphylococci (1) and PBP3 of Bacillus subtilis (28), these protein form subgroup B1 of the class B high-molecular-mass PBPs (19). When penicillin is present, they can take over the functions of most if not all the other PBPs. This has not been verified for PBP3 in B. subtilis. Thus, in enterococci and staphylococci these proteins appear to be multifunctional PBPs that are not essential for growth under laboratory conditions but synthesize peptidoglycan when the other PBPs are inhibited (5,6,7,17,18).The study of Enterococcus hirae contributed a great deal to these observations. From wild-type strain ATCC 9790 (MIC of PenG, 0.6 g/ml), resistant strain R40 (MIC of PenG, 60 g/ml) was isolated by a four-step selection procedure on plates containing increasing PenG concentrations. The greater resistance of strain R40 was attributed to overproduction of the low-affinity PBP5 (17). However, it also appeared that R40 differed from parent strain ATCC 9790 by slower growth, faster autolysis, a lower cell wall rhamnose content, and greater susceptibility to lysozyme (27). PenG-hypersusceptible strain Rev14 (MIC of PenG, 0.015 g/ml), which does not synthesize PBP5, was derived from R40 by chemical mutagenesis (18). Except for its high level of susceptibility to ␤-lactams, this strain has the properties described above for R40 (27).Expression of the PBP5-encoding gene, pbp5, in E. hirae was proposed to be under control of psr...

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“…Presumably, these PBPs are able to take over the functions of the other PBPs when the cells are grown in the presence of 13-lactam antibiotics (10, 23). Enterococcus hirae ATCC 9790 and E. hirae S185, a clinical isolate from swine intestine, have been studied in some detail (6,7,11,23). Benzylpenicillin has a MIC for E. hirae ATCC 9790 of 1 pg ml-'.…”

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confidence: 99%

“…E. hirae S185 and S185r were grown as described elsewhere (23). MICs were determined in liquid SB medium (6). Escherichia coli HB101 and JM105 (grown in Luria broth or 2XYT broth) and plasmids pBR322 and pBR325 were used for gene cloning experiments (25).…”

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confidence: 99%

Cloning and sequencing of the low-affinity penicillin-binding protein 3r-encoding gene of Enterococcus hirae S185: modular design and structural organization of the protein

et al. 1993

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The clinical isolate Enterococcus hirae S185 has a peculiar mode of resistance to penicillin in that it possesses two low-affinity penicillin-binding proteins (PBPs): the 71-kDa PBP5, also found in other enterococci, and the 77-kDa PBP3r. The two PBPs have the same low affinity for the drug and are immunochemically related to each other. The PBP3r-encoding gene has been cloned and sequenced, and the derived amino.acid sequence has been compared by computer-assisted hydrophobic cluster analysis with that of the low-affinity PBP5 ofE. hirae R40, the low-affinity PBP2' of Staphylococcus aureus, and the PBP2 of Escherichia coli used as the standard of reference of the high-Mr PBPs of class B. On the basis of the shapes, sizes, and distributions of the hydrophobic and nonhydrophobic clusters along the sequences and the linear amino acid alignments derived from this analysis, the dyad PBP3rPBP5 has an identity index of 78.5%, the triad PBP3rPBP5-PBP2' has an identity index of 291%, and the tetrad PBP3rPBP5-PBP2'-PBP2 (ofE. coli) has an identity index of 13%. In spite of this divergence, the low-affinity PBPs are of identical modular design and possess the nine amino acid groupings (boxes) typical of the N-terminal and C-terminal domains of the high-Mr PBPs of class B. At variance with the latter PBPs, however, the low-affinity PBPs have an additional =110-amino-acid polypeptide stretch that is inserted between the amino end of the N-terminal domain and the carboxy end of the membrane anchor. While the enterococcal PBP5 gene is chromosome borne, the PBP3r gene appears to be physically linked to the erin gene, which confers resistance to erythromycin and is known to be plasmid borne in almost all the Streptococcus spp. examined.The relatively low susceptibility to ,B-lactam antibiotics of enterococci compared with that of other streptococci is attributed to the presence of membrane-bound penicillinbinding proteins (PBPs) with low affinity for the drug (10,22). Presumably, these PBPs are able to take over the functions of the other PBPs when the cells are grown in the presence of 13-lactam antibiotics (10, 23). Enterococcus hirae ATCC 9790 and E. hirae S185, a clinical isolate from swine intestine, have been studied in some detail (6,7,11,23). Benzylpenicillin has a MIC for E. hirae ATCC 9790 of 1 pg ml-'. E. hirae ATCC 9790 possesses a low-affinity PBP which, on the basis of its migration on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), is referred to as the 71-kDa PBP5. Serial cultures in the presence of increasing concentrations of benzylpenicillin have led to the isolation of a mutant, strain R40, for which the MIC is 80 tFg. ml-1 and which, in parallel to this, overproduces PBP5 (11). The MIC for E. hirae S185 is 16 ,ug. ml-'. Unexpectedly, that strain possesses two lowaffinity PBPs, the 71-kDa PBP5 and 77-kDa PBP3r. Exposure to increasing concentrations of penicillin has led to the isolation of a mutant, strain S185r, for which the MIC is considerably increased (175 ,ug. ml-') and which, in ...

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The Penicillin‐Binding Proteins in Streptococcus faecalis ATCC 9790

Cited by 52 publications

References 14 publications

In Streptococcus faecium Penicillin-binding Protein 5 Alone Is Sufficient for Growth at Sub-maximal But Not at Maximal Rate

In Streptococcus faecium Penicillin-binding Protein 5 Alone Is Sufficient for Growth at Sub-maximal But Not at Maximal Rate

Redefining the Role of psr in β-Lactam Resistance and Cell Autolysis of Enterococcus hirae

Cloning and sequencing of the low-affinity penicillin-binding protein 3r-encoding gene of Enterococcus hirae S185: modular design and structural organization of the protein

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