Truncated Class 1 Integron Gene Cassette Arrays Contribute to Antimicrobial Resistance of Diarrheagenic Escherichia coli

Table 3

Number of antibiotics to which the strains with/without integrons showed resistance.

Presence of integrons	Intact/truncated integron and pathotype	No. of strains	Number (%) of antibiotics to which each strain showed resistance^†
			None	One	Two	Three	Four	Five	Six
Strains with integrons	Intact integron
	EAEC	11	0	1	0	0	5	3	2
	EPEC	2	0	0	0	0	1	0	1
	STEC	2	0	1	0	0	0	0	1
	ETEC	0	0	0	0	0	0	0	0
	Subtotal	15	1 (7%)	2 (13%)	0	0	6 (40%)	3 (20%)	3 (20%)
	Truncated integron
	EAEC	9	0	0	0	1	2	5	1
	EPEC	3	0	0	0	1	1	1	0
	STEC	0	0	0	0	0	0	0	0
	ETEC	0	0	0	0	0	0	0	0
	Subtotal	12	0	0	0	2 (16.7)	3 (25.0)	6 (50.0)	1 (8.3)
Strains without integrons	EAEC	20	6	6	5	1	1	1	0
	EPEC	32	25	2	2	1	1	0	1
	STEC	81	66	6	7	1	1	0	0
	ETEC	2	0	1	0	0	0	1	0
	Subtotal	135	97 (71.6)	15 (11.1)	14 (10.4)	3 (2.2)	3 (2.2)	2 (1.5)	1 (0.7)
Total		162	98 (60.5)	17 (10.5)	14 (8.6)	5 (3.1)	12 (7.4)	11 (6.8)	5 (3.1)

^†A total of 14 antimicrobials were tested (ampicillin, sulfamethoxazole-trimethoprim, tetracycline, nalidixic acid, streptomycin, chloramphenicol, gentamicin, cefotaxime, norfloxacin, kanamycin, ciprofloxacin, fosfomycin, imipenem, and meropenem).