To analyze the host factors affecting the drug resistance of Helicobacter pylori (Hp).

Patients with Hp infection were consecutively recruited in the Affiliated Suzhou Hospital of Nanjing Medical University from November 2021 to October 2023. Endoscopic biopsy specimens were collected for pathological diagnosis, Hp strain culture and antimicrobial susceptibility test. Nineteen factors involving the basic information, lifestyle, dietary habits, and health status of the patients were collected through electronic medical records and questionnaires. Logistic regression was used to evaluate the association between the patients' factors and drug resistance to clarithromycin, levofloxacin, amoxicillin, furazolidone, tetracycline and metronidazole.

A total of 115 patients (Hp strain 115) with Hp infection who met the inclusion and exclusion criteria were enrolled. There were 53 males (46.09%) and 62 females (53.91%), with an average age of (45.16±13.39) years. Gastroscopic pathology showed 86 cases (74.78%) of superficial gastritis, 6 cases (5.22%) of atrophic gastritis, 14 cases (12.17%) of intestinal metaplasia, 6 cases (5.22%) of low-grade intraepithelial neoplasia, and 3 cases (2.61%) of high-grade intraepithelial neoplasia/gastric cancer. The drug resistance rates of Hp strains to metronidazole, levofloxacin and clarithromycin were 91.30% (105/115), 53.04% (61/115) and 51.30% (59/115), respectively. Resistance to amoxicillin, furazolidone and tetracycline was not found. Dual drug resistance: levofloxacin + metronidazole dual resistance rate was 50.43% (58/115), clarithromycin + metronidazole dual resistance rate was 47.83% (55/115), clarithromycin + levofloxacin dual resistance rate was 36.52% (42/115). Multidrug resistance: clarithromycin + levofloxacin + metronidazole triple resistance rate was 34.78% (40/115). Multivariate Logistic regression analysis showed that (metronidazole was not included in the multivariate analysis due to the absence of sensitive strains), previous Hp eradication history (OR=74.782, 95% CI: 10.377-538.886, P < 0.001) and tap water (OR=4.919, 95% CI: 1.160-20.859, P=0.031) increased the risk of clarithromycin resistance, and age ≥50 years increased the risk of levofloxacin resistance (OR=4.261, 95% CI: 1.420-12.785, P=0.010), previous Hp eradication history (OR=5.855, 95% CI: 2.209-15.517, P < 0.001), 40-59 years old (OR= 3.269, 95% CI: 1.254-8.520, P=0.015) increased the risk of dual resistance to clarithromycin and levofloxacin.

The drug resistance rate of Hp strains isolated from patients in the Affiliated Suzhou Hospital of Nanjing Medical University to metronidazole, levofloxacin and clarithromycin were high, and dual drug resistance and multidrug resistance were prominent. Age, previous Hp eradication history and drinking water source may be associated with single or dual drug resistance to clarithromycin and levofloxacin. Comprehensive consideration, reasonable selection of antibiotics and individualized treatment should be taken into account during Hp eradication.