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Activity of cefixime against Helicobacter pylori and affinities for the penicillin-binding proteins
1Department of Chemotherapy, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan.
Abstract:
Cefixime induced the formation of rounded cells from the spiral bacillary form of Helicobacter pylori at the MIC or less. Three main penicillin-binding proteins, called A, B and C, were separated from H. pylori. Cefixime had the strongest affinity to penicillin-binding protein B. The binding of cefixime to this protein may induce the formation of rounded H. pylori cells.
Insights
Cefixime transforms spiral Helicobacter pylori (H. pylori) into rounded cells at low concentrations. This transformation is linked to cefixime binding with penicillin-binding protein B, a key target in H. pylori.
Area of Science:
- Microbiology
- Pharmacology
- Cell Biology
Background:
- Helicobacter pylori is a spiral bacterium known to cause gastrointestinal infections.
- Antibiotic resistance in H. pylori necessitates understanding drug mechanisms.
- Penicillin-binding proteins (PBPs) are crucial targets for beta-lactam antibiotics.
Purpose of the Study:
- To investigate the morphological changes induced by cefixime in Helicobacter pylori.
- To identify the specific penicillin-binding proteins (PBPs) of H. pylori targeted by cefixime.
- To elucidate the mechanism by which cefixime affects H. pylori cell shape.
Main Methods:
- Helicobacter pylori cultures were treated with cefixime at various concentrations.
- Cell morphology was observed using microscopy to document shape changes.
- Penicillin-binding proteins (PBPs) were isolated and separated from H. pylori.
- Binding affinity of cefixime to isolated PBPs was assessed.
Main Results:
- Cefixime treatment induced the formation of rounded H. pylori cells from their typical spiral bacillary form, even at sub-inhibitory concentrations.
- Three major penicillin-binding proteins (PBPs), designated A, B, and C, were identified in H. pylori.
- Cefixime exhibited the strongest binding affinity to penicillin-binding protein B (PBP B).
Conclusions:
- Cefixime induces significant morphological alterations in Helicobacter pylori, leading to cell rounding.
- The interaction between cefixime and penicillin-binding protein B is strongly implicated as the mechanism driving these observed cellular changes.
- Understanding this interaction may inform the development of novel therapeutic strategies against H. pylori infections.