Action of penicillin on Borrelia hermsii.
Borrelia hermsii, a spirochete and an etiological agent of relapsing fever, was cultivated in modified Kelly medium. Studies of the action of penicillin on B. hermsii strain HS1 revealed the following: (i) the in vitro minimum inhibitory concentration and minimum bactericidal concentration of benzylpenicillin for this strain were 0.4 and 3.1 nmol/ml (0.15 and 1.1 micrograms/ml), respectively; (ii) the primary morphological responses at the minimum bactericidal concentration of benzylpenicillin were the formation of spheroplast-like structures and an increased number of small, membranous blebs; (iii) radioactive benzylpenicillin bound to five penicillin-binding proteins in the whole cells of B. hermsii. The 50% binding concentrations of labeled penicillin for the five penicillin-binding proteins were within a factor of five of the minimum inhibitory concentration. More than one-half of the total bound labeled penicillin was associated with penicillin-binding protein 1, the penicillin-binding protein with the largest apparent molecular weight (90,000).
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins; D001898:Borrelia / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D006602:Hexosyltransferases; D008566:Membranes / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G / Q000494:pharmacology*; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G