The Inappropriateness of Using Rifampicin E-Test to Predict Rifabutin Resistance in Helicobacter pylori

Area of Science:

• Microbiology
• Antimicrobial Resistance
• Genetics

Background:

• Helicobacter pylori (H. pylori) infections are a global health concern.
• Rifamycins are crucial antibiotics for H. pylori eradication, but resistance is increasing.
• Understanding cross-resistance patterns is vital for effective treatment strategies.

Purpose of the Study:

• To investigate rifamycin cross-resistance within H. pylori isolates.
• To determine the suitability of using rifampicin E-test strips for screening rifabutin resistance in H. pylori.

Main Methods:

• Analyzed 89 H. pylori isolates.
• Determined minimum inhibitory concentrations (MICs) for rifampicin, rifapentine, rifaximin, and rifabutin.
• Compared rifamycin resistance rates using various breakpoints and performed whole-genome sequencing on resistant isolates.

Main Results:

• Observed a wide MIC distribution for rifampicin, rifapentine, and rifaximin.
• Reported varying resistance rates for rifampicin, rifapentine, and rifaximin based on different breakpoints.
• Found extremely low MICs for rifabutin, indicating no resistance, and no rpoB mutations in highly rifampicin-resistant isolates.

Conclusions:

• Demonstrated a lack of cross-resistance between rifabutin and other rifamycins in H. pylori.
• Concluded that rifampicin E-tests are inappropriate for predicting rifabutin resistance in H. pylori.