TABLE 2.

Distribution of genes encoding resistance to benzalkonium chloride, cadmium, and arsenic in tested L. monocytogenes strains.

Resistance to	Gene	Localization	No. (%) of positive strains	Origin of strains	Serotype	CCs (no. of positive strains)
Benzalkonium chloride	qacH	Transposon_Tn6188	11 (4.1%)	Human, food, environment	1/2a 1/2c 4b	CC121 (8); CC101 (1) CC9 (1) CC2 (1)
		Chromosome	4 (1.5%)	human, food	1/2a 1/2b	CC8 (1); CC20 (1); CC121 (1) CC3 (1)
	qacA	Plasmid	ND	ND	ND	ND
	qacC	Plasmid	ND	ND	ND	ND
	emrE	Chromosome_LGI1	ND	ND	ND	ND
	emrC	Plasmid_pLMST6	1 (0.4%)	Food	1/2a	CC8 (1)
Cadmium	bcrABC cadA2C2	Plasmid_pLM80	3 (1.1%)	Human, food	1/2a 1/2b	CC204 (2) CC288 (1)
	cadA1C1	Transposon_Tn5422	48 (17.8%)	Human, food, environment	1/2a	CC121 (13); CC8 (11); CC124 (2); CC21 (1); CC31 (1); CC155 (1); CC193 (1)
					1/2c	CC9 (5)
					1/2b	CC3 (11); CC5 (1); CC195 (1)
	cadA3C3	Chromosome	ND	ND	ND	ND
Arsenic	cadA4C4 arsA1A2B1B2D1D2R1R2	Chromosome_LGI2	27 (10.0%)	Human, food, environment	1/2a 4b	CC204 (6); CC14 (1) CC2 (20)
	arsCBADR	Transposon_Tn554	15 (5.6%)	Human, food	1/2c	CC9 (15)

ND, not detected; CCs, clonal complexes; LGI1, Listeria genetic island 1; LGI2, Listeria genetic island 2.