ACTIVITY OF ANTIBIOTICS AND AZOLE ANTIMYCOTICS AGAINST HELICOBACTER-PYLORI

The bacteristatic and bactericidal activities of six antibiotics from different substance classes against Helicobacter pylori were determine d. Ampicillin, imipenem, tetracycline, and amikacin inhibit the growth of all isolates at concentrations achievable in serum. Cefpirome and ofloxacin are ineffective against three and two of 41 strains, respect ively. However, the minimum bactericidal concentrations (MBC) of the s ubstances are two- to sixteen-fold higher than the minimum inhibitory concentrations (MIC). There is sufficient bactericidal activity of amp icillin and imipenem against all strains, but amikacin, ofloxacin, tet racycline, and cefpirome are unable to kill 2, 8, 12, and 18 of 25 str ains, respectively, at concentrations achievable in serum. Differences between MIC and MBC of antibiotics may contribute to the explanation of therapy failures. In addition, the inhibitory activity of seven nit roimidazole antimycotics and the triazole fluconazole was evaluated. T he nitroimidazole MICs range from 2 to 64 mg/l, with tioconazole, mico nazole, bifonazole, and ketoconazole as the most active substances. Fl uconazole, however, was ineffective at concentrations less-than-or-equ al-to 128 mg/l. The efficacy of the nitroimidazole antimycotics agains t H. pylori in vivo should be tested in a clinical trial.