Antibiotic Minimum Inhibitory Concentrations and Time???killing against Helicobacter pylori Clinical Isolates in Douala, Cameroon: Therapeutic Potential of Routinely Antibiotics

Wangnamou Marcel1, Kouitcheu Mabeku Laure Brigitte2*, Eyoum

The choice of regimens treatment against H. pylori infection in the present time should be based on knowledge of local resistance patterns and antibiotic use. In the present investigation, we tested the susceptibility of H. pylori isolated from dyspeptic patients residing in Douala- Cameroon, to routinely used drugs; amoxicillin, metronidazole, clarithromycin, erythromycin, doxycyclin and ciprofloxacin alone and in combination with two drugs each, using broth micro dilution assay and their bactericidal effectiveness in time-killing studies. Our findings showed that doxycycline, clarithromycin and ciprofloxacin, when tested alone were the most active among the antibiotics used with MIC value of 0.125 μg/ml. All the 11 different combinations showed synergism, and no case of antagonism was observed. The best combinations with the highest minimum fold inhibition (128) were Amoxicillin-Doxycyclin, Metronidazole-Clarithromycin and Metronidazole-Doxycyclin. The bactericidal studies of doxycyclin, clarithromycin and ciprofloxacin showed that ciprofloxacin at 8 MIC, produced a viability decrease of 3 log against clinical isolates tested.
Our findings clearly support the efficacy of combination therapies against H. pylori and suggest that susceptibility testing alone may not be sufficient to provide evidence of the clinical potential of anti H. Pylori agents and that time-killing study may be a useful method for evaluating the efficiency of antibiotics.