Monobactam antibiotics in subinhibitory concentrations enhance opsonophagocytosis and serum bacteriolysis in certain Escherichia coli strains.
Capsular polysaccharides are known to protect Gram-negative bacteria from complement-mediated killing and opsonophagocytosis. Monobactam antibiotics selectively inhibit penicillin-binding protein 3 (PBP3), resulting in abnormally structured peptidoglycan, causing defective cell surface structures. The authors studied the influence of subinhibitory concentrations of the monobactam antibiotics aztreonam and carumonam on serum bacteriolysis and opsonophagocytosis of four K-encapsulated and five non-K-encapsulated Escherichia coli strains. It was observed that monobactam antibiotics in subinhibitory concentrations enhanced opsonophagocytosis of the four K-encapsulated and one non-K-encapsulated E. coli strains tested. Opsonophagocytosis of the other four non-K-encapsulated E. coli strains was not enhanced. Serum bacteriolysis studies revealed that of the four K-encapsulated strains tested only one strain showed a significant enhancement of bacteriolysis after treatment with subinhibitory concentrations of monobactam antibiotics. None of the unencapsulated strains showed a significant change in percentage lysis after treatment with either aztreonam or carumonam.
Veringa
E
E
Laboratory of Medical Microbiology, University of Utrecht, The Netherlands.
Box
A
A
Rozenberg-Arska
M
M
Verhoef
J
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001398:Aztreonam / Q000494:pharmacology* / Q000031:analogs & derivatives; D001433:Bacteriolysis / Q000187:drug effects; D001770:Blood Bactericidal Activity / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D009895:Opsonin Proteins; D010587:Phagocytosis / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D000954:Antigens, Surface; C030659:K antigens; D009895:Opsonin Proteins; C044145:carumonam; D001398:Aztreonam