'In vitro' development of metronidazole, erythromycin, amoxicillin and gentamicin resistance in Helicobacter pylori

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Helicobacter pylori is a significant human pathogen.
• Antimicrobial resistance in H. pylori poses a therapeutic challenge.
• Understanding resistance mechanisms is crucial for effective treatment.

Purpose of the Study:

• To investigate the rapid development of antimicrobial resistance in Helicobacter pylori clinical isolates.
• To determine the cross-resistance patterns of H. pylori to different antibiotics.
• To assess the potential for inducing resistance to metronidazole, erythromycin, gentamicin, and amoxicillin.

Main Methods:

• Serial passage of 37 H. pylori clinical isolates on increasing antibiotic concentrations.
• Determination of Minimum Inhibitory Concentrations (MICs) for metronidazole, erythromycin, gentamicin, and amoxicillin.
• Evaluation of resistance development across multiple passages.

Main Results:

• Rapid development of high-level metronidazole resistance (up to 512-fold increase in MICs) in five strains.
• Metronidazole-resistant strains showed unchanged MICs for erythromycin, gentamicin, and amoxicillin.
• One strain developed high-level resistance to erythromycin (up to 32-fold) and gentamicin (up to 64-fold).
• No amoxicillin-resistant H. pylori strains were obtained through serial passage.

Conclusions:

• Helicobacter pylori can rapidly acquire high-level resistance to metronidazole.
• Cross-resistance patterns are limited, with amoxicillin resistance not readily induced.
• These findings highlight the potential for rapid resistance development to certain antibiotics, emphasizing the need for careful antimicrobial stewardship.