Redefining the role of psr in beta-lactam resistance and cell autolysis of Enterococcus hirae.
The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the beta-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 beta-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 beta-lactam resistance or in the regulation of cell autolysis in E. hirae.
Sapunaric
Frédéric
F
Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, Massachusetts 02111, USA.
Franssen
Christine
C
Stefanic
Patrick
P
Amoroso
Ana
A
Dardenne
Olivier
O
Coyette
Jacques
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001433:Bacteriolysis; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D016983:Enterococcus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D006602:Hexosyltransferases / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; C080374:Psr protein, Enterococcus hirae; D012097:Repressor Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase