Antibiotic resistance in Neisseria denitrificans.
An ampicillin-resistant strain of Neisseria denitrificans was produced by serial passage of the organisms in media containing increased concentrations of antibiotic. The 400-fold increase in resistance obtained was a relatively stable characteristic. Ampicillin resistance in this organism was apparently related to a loss or modification of the penicillin-binding proteins associated with the cytoplasmic membranes. Membranes isolated from the ampicillin-resistant strain bound significantly less radioactive penicillin than those isolated from the parent strain and revealed one major and three minor penicillin-binding proteins. All four penicillin-binding proteins were present in reduced amounts or had a decreased capacity for penicillin binding in the ampicillin-resistant cells. The increased resistance did not involve enzymic degradation of the antibiotic or a general reduction in the permeability of the outer layers of the cell. No difference in the amount of peptidoglycan present in the parent and ampicillin-resistant cells or in the gross chemical structure of the peptidoglycans of the two strains was observed.
D000667:Ampicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002352:Carrier Proteins / Q000302:isolation & purification; D002463:Cell Membrane Permeability; D005840:Gentian Violet / Q000378:metabolism; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D009154:Mutation; D009343:Neisseria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D010403:Penicillin Resistance; D010406:Penicillins / Q000378:metabolism; D010457:Peptidoglycan / Q000032:analysis; D013395:Sucrose / Q000378:metabolism
D000900:Anti-Bacterial Agents; D002352:Carrier Proteins; D010406:Penicillins; D010457:Peptidoglycan; D013395:Sucrose; D000667:Ampicillin; D005840:Gentian Violet