Levofloxacin and Rifampin Resistance in Helicobacter pylori Isolates from Central-Western Colombia: Role of gyrA Mutations in Fluoroquinolone Resistance

Background: Helicobacter pylori causes one of the most prevalent chronic bacterial infections worldwide. Data about H. pylori resistance rates to levofloxacin and rifampin (antimicrobials for second-, third- or fourth-line therapy) in Colombia and South America are scarce. The present study aimed to assess levofloxacin and rifampin resistance rates among 61 H. pylori isolates from the western-central region of Colombia and to identify gyrA point mutations associated with levofloxacin resistance. Methods: For this purpose, antimicrobial susceptibility was determined using the E-test method and gyrA mutations in levofloxacin-resistant isolates were identified by PCR amplification followed by DNA sequencing. Results: Resistance rates to levofloxacin and rifampin were 24.6% and 13.1%, respectively. Among the 15 levofloxacin-resistant isolates, 6 (40%) isolates had ≥2 gyrA mutations and 5 of them exhibited high (≥32 mg/L) levofloxacin MICs. In addition, two new mutations (Y90C and V89D) were also detected. Conclusions: Clinically relevant resistance to levofloxacin and rifampin was detected among H. pylori isolates from central-western Colombia. Multiple gyrA mutations were identified in a significant proportion of levofloxacin-resistant isolates and were mainly associated with high MIC values, highlighting the need for regional surveillance to guide eradication therapies.