[Antibiotic resistance of Helicobacter pylori in an infectious disease referral center]
Lopez-Vidal Y. Sigfrido Rangel-Frausto M. Calva JJ.
Departamento de Microbiologia, Facultad de Medicina, U.N.A.M., Mexico, D.F.
OBJECTIVE: To estimate the frequency of H. pylori clinical isolates resistant to six commonly used antimicrobials. DESIGN: Cross-sectional observational study. SETTING: A tertiary-referral health care institution in Mexico City. PARTICIPANTS: 31 isolates of H. pylori from 31 patients with chronic antral gastritis were obtained from gastric mucosal biopsy specimens. MAIN OUTCOME MEASURE: The Minimum Inhibitory Concentration (MIC) to ampicillin, amoxycillin, tetracycline, doxycycline, metronidazole and to colloidal bismuth subcitrate was determined by the agar plate dilution test. RESULTS: All isolates showed to be susceptible to the former four antibiotics but only in 46% and 55% growth was inhibited by 8 micrograms/mL and 16 micrograms/mL of metronidazole, respectively. All isolates were inhibited by < or = 128 micrograms/mL of bismuth. A 50% increase in the percentage of metronidazole-resistant isolates (MIC > or = 8 micrograms/mL) between 1988 to 1992 was observed. CONCLUSION: There is a need of future studies in our setting aimed at assessing the cost/effectiveness of diverse H. pylori-associated peptic ulcer treatment options.