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Detection of penicillin-binding proteins immunologically related to penicillin-binding protein 5 of Enterococcus
M Ligozzi1, M Aldegheri, S C Predari
1Istituto di Microbiologia, Università di Verona, Italy.
Insights
Penicillin-binding protein 5 (PBP 5) in Enterococcus species is linked to penicillin resistance. Antibodies detected PBP 5-related proteins in some strains, with resistance correlating to its presence or absence.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Penicillin-binding proteins (PBPs) are crucial targets for beta-lactam antibiotics.
- High-molecular mass, low-affinity PBPs, like PBP 5, are implicated in penicillin resistance in Enterococcus species.
- Enterococcus species are significant human pathogens, and antibiotic resistance is a growing concern.
Purpose of the Study:
- To investigate the presence and role of PBP 5-related proteins in Enterococcus faecium and Enterococcus faecalis.
- To determine the correlation between PBP 5 expression and penicillin resistance in these species.
Main Methods:
- Generation of polyclonal antibodies against Enterococcus hirae PBP 5.
- Immunological detection of PBP 5-related membrane proteins in E. faecium and E. faecalis strains.
- Determination of penicillin minimal inhibitory concentrations (MICs) for various strains.
Main Results:
- A membrane protein immunologically related to E. hirae PBP 5 was detected in several E. faecium and E. faecalis strains.
- Some E. faecium strains lacking the PBP 5-related protein developed resistance upon increased penicillin exposure.
- Absence of a PBP 5-related protein in some E. faecalis strains was associated with an inability to select for stable penicillin resistance.
Conclusions:
- PBP 5 or related proteins play a role in penicillin resistance in E. faecium and E. faecalis.
- The presence or absence of PBP 5-related proteins may influence the selection and stability of penicillin resistance in enterococci.
Abstract:
Penicillin-binding protein (PBP) 5 of Enterococcus hirae ATCC 9790 belongs to the class of the high-molecular mass, low-affinity PBPs which have been correlated with penicillin resistance in most Enterococcus species. Polyclonal antibodies were raised against PBP 5 and used to detect immunologically related membrane proteins in E. faecium and E. faecalis strains. Several strains of both species were found to have a membrane protein of similar molecular mass to E. hirae PBP 5 which reacted with the antibodies. Some E. faecium strains did not react with antibodies but their derivatives with increased penicillin minimal inhibitory concentrations did. In some E. faecalis strains the lack of a PBP 5-related protein was associated with failure to select stable penicillin-resistant derivatives.