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.