Detection of genotypic clarithromycin-resistant Helicobacter pylori by string tests

Table 2 Result of polymerase chain reaction-restriction fragment length polymorphism from the string test

		String PCR-RFLP
		Sensitive	Resistant
E-test	Sensitive	36	2
	Resistant	1	4

Five were resistant to clarithromycin as confirmed by E-tests in 43 Helicobacter pylori isolates. Among these 43 patients undergoing the string test, four 23S rDNA amplicons from strings were digested by BsaI, indicating a mutation site A to G at 2142 of 23S rRNA. PCR-RFLP: Polymerase chain reaction-restriction fragment length polymorphism.