title: Antibacterial activities of beta-lactamase inhibitors associated with morphological changes of cell wall in Helicobacter pylori.
abstract: BACKGROUND
  Recent study has demonstrated that beta-lactamase inhibitors including clavulanate, sulbactam and tazobactam have an vitro antibacterial effect on Helicobacter pylori. Here we describe the relationship between viability and cell profiles of H. pylori exposed to beta-lactamase inhibitors and some antibiotics in a short-time course.
  
  
  METHODS
  The antibacterial effects of beta-lactamase inhibitors including clavulanate, sulbactam and tazobactam on the bacterial viability of and morphological changes in H. pylori ATCC43504 were examined.
  
  
  RESULTS
  The beta-lactamase inhibitors such as clavulanate and sulbactam alone decreased the viable counts of H. pylori, depending on the antibiotic concentrations. Exposure to these beta-lactamase inhibitors resulted in morphological changes of cell shape, cell-wall disintegration and cell lysis. Among these beta-lactamase inhibitors, clavulanate was the most active, causing a decrease in viable counts and morphological changes such as short filamentous to sphaeroplast formation and lysis. One x minimum inhibitory concentration (MIC) of amoxicillin plus 1 x MIC of clavulanate decreased viable counts effectively compared with 1 x MIC of amoxicillin or 1 x MIC of clavulanate alone, and induced morphological changes of cell shape and cell wall.
  
  
  CONCLUSIONS
  Our results suggest that the beta-lactamase inhibitors alone have concentration-dependent antibacterial activities against H. pylori and affect the morphology of the cell shape and the cell wall in vitro.
authors.affiliation: Department of Laboratory Medicine, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Hamamatsu 431--3192, Japan.
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Horii
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Mase
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Taku
authors.initials: T
authors.lastname: Kimura
authors.forename: Michio
authors.initials: M
authors.lastname: Ohta
authors.forename: Masato
authors.initials: M
authors.lastname: Maekawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanno
authors.forename: Miya
authors.initials: M
authors.lastname: Kobayashi
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001433:Bacteriolysis; D002473:Cell Wall / Q000187:drug effects* / Q000648:ultrastructure; D016480:Helicobacter pylori / Q000187:drug effects* / Q000254:growth & development* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams