Molecular mechanisms of quinolone, macrolide, and tetracycline resistance among Campylobacter isolates from initial stages of broiler production

Figures & data

Table 1. Origin of Campylobacter isolates, species relationships and resistotypes with respect to stage of production.

Production stage^a	Farm	Flock	Sampling year	Number of birds/farm	Age of selected birds (weeks)	Species	Resistotypes^b
GPBF	1	A	2002/2003	14,000	28	C. jejuni	NZA, NZAT, NZT^c, T, PanS
		B	2003	14,000	25	C. jejuni	T
		C	2004	14,000	26	C. jejuni	NZT^c, T
	2	D	2002	14,000	43	C. jejuni	NZ^c, NZA, T, PanS
		E	2002/2003	14,000	21	C. jejuni	NZAT^c
		F	2003/2004	14,000	37	C. jejuni	NZT^c
	3	G	2002	16,000	57	C. jejuni	NZ^c
		H	2002/2003	16,000	23	C. jejuni	NZ^c, NZA
		I	2003/2004	16,000	27	C. jejuni	T
		J	2005	16,000	30	C. jejuni	NZT^c
	4	L	2002/2003	16,000	23	C. jejuni	NZ^c, PanS
		M	2003	16,000	18	C. jejuni/C. coli	T, NZT, NZAT^c
		N	2004	16,000	23	C. jejuni	NZT^c, T
	5	O	2002	16,000	57	C. jejuni	NZ^c, NZA, PanS
		P	2002/2003	16,000	23	C. jejuni	NZ^c, NZT
		Q	2003	16,000	13	C. jejuni/C. coli	NZ^c, NZA, T
		R	2004	16,000	20	C. jejuni	NZT, NZAT^c
PBF	P1	P-A	2003	8300	16	C. jejuni	NZAT^c
	P2	P-B	2003	11,600	16	C. jejuni	NZ, NZA^c, NZAT
	P3	P-C	2003	16,500	17	C. jejuni/C. coli	NZT, NZAT^c
	P4	P-D	2003	8800	11	C. jejuni	NZT^c, NZAT
	P5	P-E	2003	16,000	14	C. jejuni	NZ, NZT, NZAT^c
	P6	P-F	2003	16,000	25	C. jejuni/C. coli	NZ^c, NZT, NZAT
	P7	P-G	2003	12,000	10	C. jejuni/C. coli	NZA^c, NZAT
	P8	P-H	2003	12,000	5	C. coli	NZET ^c^,^d
	P9	P-I	2003	20,000	26	C. jejuni/C. coli	NZT, NZAT^c
	P10	P-J	2003	20,000	12	C. jejuni	PanS
	P12	P-L	2004	8000	9	C. jejuni/C. coli	T, NZT^c, NZAT
	P13	P-M	2004	16,000	18	C. jejuni	NZT^c

^a Broiler GPBF and PBF.

^b N, nalidixic acid; Z, ciprofloxacin; A, amoxicillin; E, erythromycin; T, tetracycline; PanS, pan-susceptible (e.g. NZT is resistant to nalidixic acid, ciprofloxacin and tetracycline).

^c Resistotypes in which the mechanisms of quinolone resistance were investigated. For the tetracycline resistance, one isolate by resistotype was investigated.

^d Only one population of C. coli resistant to erythromycin.

Table 2. Mechanisms of tetracycline resistance in Campylobacter isolates with indication of location of tetO investigated by Southern blotting, MICs, sizes of isolated plasmids and recipient strains (Rec1 and Rec2) in mating experiments.

Production stage^a	Farm	Flock	Sampling year	Number of isolates tested	Resistotype	Species	MIC tetracycline (mg/l)	Plasmid sizes (kb)	tetO location
GPBF	1	A	2002/2003	74	NZT	C. jejuni	96	–	CR
					NZAT	C. jejuni	64	–	CR
					T	C. jejuni	>256	62.8	62.8 kb p
		B	2003	16	T	C. jejuni	96	–	CR
		C	2004	12	NZT^b;	C. jejuni	32	60	60 kb p
					T	C. jejuni	48	–	CR
	2	D	2002	60	T	C. jejuni	48	65.6	65.6 kb p
		E	2002/2003	15	NZAT	C. jejuni	64	–	CR
		F	2003/2004	8	NZT	C. jejuni	64	–	CR
	3	I	2003/2004	15	T	C. jejuni	64	56.9	56.9 kb p
		J	2005	27	NZT	C. jejuni	>256	66.2	66.2 kb p
	4	M	2003	60	T	C. jejuni	64	–	CR
					NZAT	C. jejuni	64	–	CR
					T	C. coli	>256	–	CR
					NZT	C. coli	>256	–	CR
					NZT	C. jejuni	32	–	CR
		N	2004	12	T	C. jejuni	64	68	68 kb p
	5	P	2002/2003	74	NZT	C. jejuni	64	–	CR
		Q	2003	27	T	C. coli	128	–	CR
		R	2004	24	NZT	C. jejuni	48	54.9	54.9 kb p
					NZAT	C. jejuni	64	–	CR
PBF	P1	P-A	2003	9	NZAT	C. jejuni	48	–	CR
	P2	P-B	2003	18	NZAT	C. jejuni	16	–	CR
	P3	P-C	2003	28	NZT^b;	C. jejuni	>256	48.3, 60	60 kb p
					NZAT	C. coli	>256	5.3, 36.1	36.1 kb p
	P4	P-D	2003	6	NZT	C. jejuni	>256	60.2	60.2 kb p
					NZAT	C. jejuni	>256	32.6	32.6 kb p
	P5	P-E	2003	19	NZT	C. jejuni	96	35.4, 78.3	35.4 kb p
					NZAT^b;	C. jejuni	>256	55.2	55.2 kb p
	P6	P-F	2003	19	NZT	C. jejuni	16	64	64 kb p
					NZAT	C. coli	96	–	CR
	P7	P-G	2003	10	NZAT^b;	C. jejuni	96	3.3, 5.3, 6.6, 59.4	3.3 kb p
	P8	P-H	2003	25	NZET	C. coli	64	66.9	66.9 kb p
	P9	P-I	2003	23	NZT	C. coli	256	6.7, 24.2, 60.5	CR
					NZAT	C. jejuni	48	–	CR
	P12	P-L	2004	12	T	C. coli	128	–	CR
					NZT	C. coli	>256	4.2, 5.4, 19.9, 58	58 kb p
					NZAT	C. jejuni	16	13.4	CR
	P13	P-M	2004	11	NZT	C. jejuni	24	–	CR
Recipient strains	Rec1	–	2004	–	NZAE	C. jejuni	0.19	–	–
	Rec2	–	2005	–	NZAE	C. jejuni	0.125	–	–

CR, chromosome; p, plasmid; N, nalidixic acid; Z, ciprofloxacin; A, amoxicillin; E, erythromycin; T, tetracycline.

^a Broiler GPBF and PBF.

^b Strains selected for mating experiments as donors.

Figure 1. Comparison of the KpnI-PFGE profiles of isolates from flocks in which tetO was located both on the chromosome and on the plasmid. The comparison was carried out with Dice index and the tolerance and optimization values of 1%. Dendrogram constructed with unweighted pair-group arithmetic average clustering. Each population is defined by their PFGE profile. The highest similarity between populations within a flock (P-L) is marked with an asterisk (62%).

Figure 2. RFLP-PCR of flaA from the recipient, donor, and transconjugant isolates. M, molecular marker (50-bp ladder; Ge Healthcare Life Sciences, Buckinghamshire, UK). Rec1 and Rec2 are recipient isolates. P-C, C, P-G, and P-E are donor isolates; lanes 1 to 5 represent the transconjugants P-C (Rec1), P-G (Rec1), C (Rec2), P-E (Rec2) and P-G (Rec2), respectively.