Characterization of an Enterococcus hirae penicillin-binding protein 3 with low penicillin affinity.

AUTOR(ES)

Piras, G

RESUMO

Enterococcus hirae S185, a clinical isolate from swine intestine, exhibits a relatively high resistance to penicillin and contains two 77-kDa penicillin-binding proteins 3 of high (PBP 3s) and low (PBP 3r) affinity to penicillin, respectively. A laboratory mutant S185r has been obtained which overproduces PBP 3r and has a highly increased resistance to penicillin. Peptide fragments specifically produced by trypsin and SV8 protease digestions of PBP 3r were isolated, and the amino acid sequences of their amino terminal regions were determined. On the basis of these sequences, oligonucleotides were synthesized and used as primers to generate, by polymerization chain reaction, a 233-bp DNA fragment the sequence of which translated into a 73-amino-acid peptide segment of PBP 3r. These structural data led to the conclusion that the E. hirae PBP 3r and the methicillin-resistant staphylococcal PBP 2' are members of the same class of high-Mr PBPs. As shown by immunological tests, PBP 3r is not related to PBP 3s but, in contrast, is related to the 71-kDa PBP 5 of low penicillin affinity which is responsible for penicillin resistance in E. hirae ATCC 9790 and R40.

Documentos Relacionados

• 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.
• Overproduction of a low-affinity penicillin-binding protein and high-level ampicillin resistance in Enterococcus faecium.
• The Gene Encoding the Low-Affinity Penicillin-Binding Protein 3r in Enterococcus hirae S185R Is Borne on a Plasmid Carrying Other Antibiotic Resistance Determinants
• Low-affinity penicillin-binding protein associated with beta-lactam resistance in Staphylococcus aureus.
• Identification of a genetic element (psr) which negatively controls expression of Enterococcus hirae penicillin-binding protein 5.