Quinolone-based regimens have been used as rescue therapy for eradication of Helicobacter pylori (H. pylori), especially as resistance to clarithromycin and metronidazole has increased. Levofloxacin is now well recognised as an effective eradication therapy, but increased use has led to concerns about increasing resistance due to mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene of H. pylori.
Sitafloxacin is a newer fluoroquinolone with a wide spectrum of activity, and is promising as part of an H. pylori eradication regimen. However there is no data on the efficacy of sitafloxacin-containing rescue regimens in association with gyrA mutation status.
To investigate, researchers randomised patients who had failed first- and second-line eradication regimens, into either EAS group (esomeprazole (20 mg, b.i.d.), amoxicillin (500 mg, q.i.d.), and sitafloxacin (100 mg, b.i.d.) or EMS group (esomeprazole (20 mg, b.i.d.), metronidazole (250 mg, b.i.d.), and sitafloxacin (100 mg, b.i.d.). Both regimens were given for 10 days. The MICs of sitafloxacin, amoxicillin, and metronidazole and the gyrA mutation status of the H. pylori were determined before treatment.
All patients with gyrA mutation-negative strains (24 patients in the EAS and 16 EMS patients) achieved complete eradication. In contrast, in 37 EAS patients with gyrA mutation-positive strains, 26 of these eradicated (70.3%) and in 39 EMS patients with gyrA mutations, 26 were eradicated (66.7%) (p = .81). Logistic regression analyses demonstrated that MICs of sitafloxacin, which were strongly associated with gyrA mutation status, were independently associated with successful eradication in both groups. Researchers concluded that sitafloxacin-containing regimens were successful and that gyrA mutation status is an important factor in predicting successful eradication.
Helicobacter. 2016 Aug;21(4):286-94. doi: 10.1111/hel.12286