Journal of Antimicrobial Chemotherapy (2000) 45, 807-811
© 2000 The British Society for Antimicrobial Chemotherapy
The 7
-methoxy substituent in cephem or oxacephem antibiotics enhances in vivo anti-Helicobacter felis activity in mice after oral administration
a Shionogi Research Laboratories, 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825; b Shionogi Research Laboratories, 5-12-4 Sagisu, Fukushima-ku, Osaka 553-0002; c Shionogi Institute For Medical Science, 2-5-1 Mishima, Settsu, Osaka 566-0022, Japan
The in vivo antibacterial activities of 7
-methoxy-cephems or 7
-methoxy-1-oxacephems and their demethoxy congeners after oral administration were compared in a mouse model of gastric infection with Helicobacter felis. The MICs of all four pairs of compounds with and without the 7
-methoxy substituent were within one two-fold dilution for H. felis and Helicobacter pylori, but the 7
-methoxy compounds were at least four-fold more active at bacterial eradication than their demethoxy congeners. Since these compounds are not absorbed after oral administration, they are likely to have gained direct access to the bacteria from the gastric cavity. Thus the 7
-methoxy substituent may enhance in vivo activity by promoting the gastric mucus permeability of the compounds or by allowing the compounds to remain longer in the gastric cavity.
* Corresponding author. Tel: +81-6-6331-8081; Fax:+81-6-6331-8612; E-mail: yoshinao.kobayashi{at}shionogi.co.jp