Drug susceptibility pattern of helicobacter pylori in patients with dyspepsia at the Kenyatta National Hospital

Abstract

The aim of the study was to determine the drug susceptibility pattern of H pylori to metronidazole, clarithromycin, amoxicillin and tetracycline in patients presenting with dyspepsia at the Kenyatta National Hospital.

The study design was a cross-sectional descriptive study, carried out at the Kenyatta National Hospital, Nairobi, Kenya.

Patients aged 15 years and above, presenting with dyspepsia and referred for upper gastrointestinal endoscopy were recruited into the study. Informed consent was obtained for both endoscopy and participation in the study. The endoscopic findings were noted. Six gastric biopsies were taken from each patient. The rapid urease test was carried out on three of the biopsies and three biopsies were cultured under microaerophilic conditions. Susceptibility testing was carried out for metronidazole, clarithromycin, amoxicillin and tetracycline.

138 male and 129 female patients aged 15-85 years, with a mean age of 45.4 years were studied. Gastritis was the most common endoscopic finding, occurring in 55% of the total population. Normal-looking mucosa was found in 27% of the patients and 16% were found to have peptic ulcer disease. The rapid urease test was positive in 184 patients (69%). The culture yield was

62% of the CLO positive biopsies. The MIC90 was 256 mg/L for metronidazole, 1.5mgIL for clarithromycin, 1.5mg/L for tetracycline and 0.75 mg/L for amoxicillin.

The CLO test was of strong predictive value for the isolation of H pylori on culture. A negative test was however associated with a positive culture in 19 cases (14% false negative eLO tests). All isolated H pylori organisms were resistant to metronidazole with an MIC90 of over 256 mg/L, There was a rising MIC90 for tetracycline and metronidazole compared to that found by Sang et al in a previous study in 1991 (38). The MIC90 for amoxicillin and clarithromycin were also found to be close to the upper limit of the susceptibility range. The MIC values for amoxicillin were significantly higher in the female patients (over 0.38 mgIL) with a p value of 0.02 but showed no significant variation for age. The MIC values for metronidazole, tetracycline and clarithromycin showed no significant difference for age or gender. MIC values for tetracycline were significantly higher for patients with duodenitis and duodenal ulcer with p values of 0.009 and 0.02 respectively.