Table 5.

Ecological distribution of antibiotic resistance of Listeria monocytogenes strains in the three examined dairy cattle farms (n = 137)

Samples		Total no. of isolates	Antibiotics
			P	N	FOX	NA	AML	OB	CTX	AK	E	NOR	TE	CN	S	SXT	CIP	C	NET	VA
Farm I	Animal samples	17	17	17	17	17	13	11	9	5	5	0	0	9	4	0	0	0	0	0
	Environmental samples	6	6	6	6	4	4	3	5	3	3	0	0	1	2	0	0	0	0	0
	Milking equipment	6	6	6	6	4	4	3	2	2	2	0	0	1	2	0	0	0	0	0
	Total	29	29	29	29	21	21	17	16	10	10	0	0	11	8	0	0	0	0	0
Farm II	Animal samples	40	40	40	40	40	40	40	40	40	40	36	29	31	30	25	17	0	0	0
	Environmental samples	10	10	10	10	10	10	10	10	10	10	7	6	6	8	5	8	0	0	0
	Milking equipment	16	16	16	16	16	16	16	16	16	16	12	11	10	10	7	7	0	0	0
	Total	66	66	66	66	66	66	66	66	66	66	55	46	47	48	37	32	0	0	0
Farm III	Animal samples	27	27	27	27	27	27	27	21	23	23	21	17	9	10	19	16	5	0	0
	Environmental samples	7	7	7	7	7	7	7	5	6	6	5	7	1	2	4	4	1	0	0
	Milking equipment	8	8	8	8	8	8	8	6	8	8	6	3	5	3	7	5	3	0	0
	Total	42	42	42	42	42	42	42	32	37	37	32	27	15	15	30	25	9	0	0
Total		137	137	137	137	137	129	125	114	113	113	87	73	73	71	67	57	9	0	0
Resistance (%)		100	100	100	100	100	94.2	91.2	83.2	82.5	82.5	62.8	53.3	53.3	50.4	48.9	32	6.6	0	0

P, penicillin; N, neomycin; FOX, cefoxitin; NA, nalidixic acid; AML, amoxicillin; OB, cloxacillin; CTX, cefotaxime; AK, amikacin; E, erythromycin; NOR, norfloxacin; TE, tetracycline; CN, gentamicin; S, streptomycin; SXT, sulphamethazole/trimethoprim; CIP, ciprofloxacin; C, chloramphenicol; NET, netilmicin; VA, vancomycin