Interaction of Vibrio cholerae cells with beta-lactam antibiotics: emergence of resistant cells at a high frequency.
Unlike other gram-negative enteric bacteria, Vibrio cholerae cells were equally susceptible to penicillin and ampicillin and in general more susceptible than Escherichia coli to most of the beta-lactam antibiotics. The turbidity of penicillin-treated cultures contained to increase exponentially for about 3 h, although the cell viability declined rapidly within 30 min of penicillin addition. Prolonged treatment with beta-lactam antibiotics produced cells resistant to these antibiotics. A fluctuation test indicated that this resistance might be due to adaptive mutation. Cells resistant to a beta-lactam exhibited broad cross-resistance to other beta-lactam antibiotics. A new 12,000-Da outer membrane protein was detected both in beta-lactam-resistant cells and in wild-type cells growing in medium containing beta-lactam antibiotics. While the penicillin-resistant cells had all of the penicillin-binding proteins (PBPs) present in the parental cells, significant differences in the relative proportion of low-molecular-weight PBPs were seen. The low-molecular-weight PBPs from resistant cells seemed to form more stable complexes with penicillin than those from the parental strain.
Sengupta
T K
TK
Biophysics Division, Indian Institute of Chemical Biology, Jadavpur, Calcutta.
Chaudhuri
K
K
Majumdar
S
S
Lohia
A
A
Chatterjee
A N
AN
Das
J
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D002478:Cells, Cultured; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D010403:Penicillin Resistance; D010405:Penicillinase / Q000032:analysis; D014734:Vibrio cholerae / Q000187:drug effects* / Q000648:ultrastructure; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D047090:beta-Lactams; D010405:Penicillinase