Novel chromogenic medium-based method for the rapid detection of Helicobacter pylori drug resistance

Table 2 Breakpoints for verifying antibiotic concentrations (μg/mL)

H. pylori	LVX				CLR				MTZ				AMX
	0.25	0.5	1	2	0.25	0.5	1	2	1	2	4	8	0.03	0.06	0.13	0.25
G27	+	-	-	-	+	-	-	+	+	+	-	-	+	-	-	-
26695	+	-	-	-	+	-	-	+	+	+	-	-	+	-	-	-
159	+	+	-	-	+	+	-	+	+	+	+	-	+	+	-	-
161	+	+	-	-	+	+	-	+	+	+	+	-	+	+	-	-
162	+	+	-	-	+	+	-	+	+	+	-	-	+	-	-	-
163	+	+	-	-	-	-	-	+	+	+	+	-	+	+	-	-
286	+	+	-	-	+	+	-	+	+	+	+	-	+	+	-	-
287	+	+	-	-	+	+	-	+	+	+	+	-	+	+	+	-
289	+	+	+	-	+	+	+	+	+	+	+	-	+	+.	-	-
290	+	+	+	-	+	+	-	+	+	+	+	+	+	+	-	-

By adding antibiotics with certain concentrations to the Columbia medium, sensitive and resistant strains (working concentration of (1 × 10⁵ CFUs/mL) could be cultured. Adding 0.5 μg/mL of levofloxacin, 0.5 μg/mL of clarithromycin, 4 μg/mL of metronidazole, and 0.06 μg/mL of amoxicillin could inhibit the growth of sensitive bacteria (G27, 26695), while hardly affect the growth of resistant bacteria (159, 161, 162, 163, 286, 287, 289, 290). Helicobacter pylori: H. pylori; LVX: Levofloxacin; CLR: Clarithromycin; MTZ: Metronidazole; AMX: Amoxicillin.