Related Experiment Videos
In vitro selection of resistant Helicobacter pylori
C E Haas1, D E Nix, J J Schentag
1Center for Clinical Pharmacy Research, School of Pharmacy, State University of New York, Buffalo.
Abstract:
Four strains of Helicobacter pylori were subjected to an in vitro serial passage technique to compare the propensity of the organisms to develop resistance to seven classes of antibacterial agents. The passages were made on serially doubling concentrations of antibacterial agents incorporated into agar starting at one-half the base-line MIC. The frequency of spontaneous resistance was also determined for each strain at four and eight times the MIC of each antibacterial agent. Strains resistant to ciprofloxacin, metronidazole, erythromycin, and tobramycin were isolated. The experiments failed to select organisms resistant to bismuth subsalicylate, furazolidone, or amoxicillin, although the MIC of amoxicillin was increased 4- to 16-fold. With the exception of erythromycin, organisms with the selected resistance were stable after at least three passages on antibacterial agent-free medium. Spontaneous resistance rates were generally of a low magnitude and were not predictive of the serial passage results.
Insights
This study compared Helicobacter pylori
Area of Science:
- Microbiology
- Antimicrobial Resistance
- Infectious Diseases
Background:
- Helicobacter pylori is a significant human pathogen.
- Antibiotic resistance in H. pylori complicates treatment.
- Understanding resistance development is crucial for effective therapies.
Purpose of the Study:
- To compare the in vitro development of resistance in H. pylori strains.
- To evaluate resistance to seven classes of antibacterial agents.
- To assess spontaneous resistance rates.
Main Methods:
- Serial passage technique with doubling concentrations of antibiotics.
- Testing against ciprofloxacin, metronidazole, erythromycin, tobramycin, bismuth subsalicylate, furazolidone, and amoxicillin.
- Determination of minimum inhibitory concentrations (MICs).
Main Results:
- H. pylori strains developed resistance to ciprofloxacin, metronidazole, erythromycin, and tobramycin.
- No resistance was selected for bismuth subsalicylate, furazolidone, or amoxicillin, though amoxicillin MICs increased.
- Selected resistance was generally stable, except for erythromycin.
Conclusions:
- H. pylori exhibits variable resistance development to different antibacterial agents.
- Serial passage is a useful method for assessing resistance potential.
- Spontaneous resistance rates did not predict serial passage outcomes.