TABLE 2.

Characterization of ESBL-producing Escherichia coli isolates from wild birds on the Baltic Sea coast of Poland

Isolate no.	Origin	Antibiotic resistance phenotypec	ESBL bla genes	Antibiotic resistance genes	XbaI PFGEe	Presence of colicin (the gene cib)	Phylogenetic group	Conjugation to E. coli	Conjugation to Salmonella	Plasmid incompatibility groupe	RFLP pattern (EcoRV)	Plasmid size (kb)	Additional genes on ESBL-carrying plasmid
1 PL	Mallard	AAcCfCipNa	blaCTX-M-1		a	−	A	+	+
5 PL	Mallard	ACfSSuSxtT	blaCTX-M-1	strA, aadA1, sul2, tetB	b	−	B1	+	+	IncN	I	35
78 PLa	Mallard	ACCfSSuSxtT	blaCTX-M-1	cat, strA, sul1, sul2, tetB, int1, I1,d 2.5 kb, dhfr1-aadA1	c	−	B2	−	−
17 LA CEF	Herring gull	ACfSu	blaCTX-M-1	sul2	e	+	A	+	+	IncI1	II	90	cib, sul2
11 LA CEF	Herring gull	ACfGnSuSxt	blaCTX-M-1	sul1, int1, I1, 2.0 kb, dhfr12-aadA2	d	−	B2	+	+	ND	III	80	int1, I1, 2.0 kb, dhfr12-aadA2
6 LA CEF	Herring gull	ACfSSuSxtT	blaCTX-M-9	blaTEM-1b, strA, aadA1, sul2, tetD	ND	−	D	−	−
88	Waterbird feces	ACf	blaSHV-12	int1, I1, 2.1 kb, aadA2	g	−	A	+	+	IncI1	IV	95
96	Waterbird feces	ACfNaSuSxtT	blaCTX-M-1	blaTEM-1b, dhfr17, aadA5, sul2, tetA, int1	h	−	B1	+	+	IncI1	V	100	sul2, int1, dhfr17, aadA5
8Nb	Waterbird feces	ACfCipNaSSuSxtT	blaCTX-M-15	blaOXA-1, aac(6′)-Ib-cr, sul1, tetA, int1, I1, 1.7 kb, dhfr17-aadA5	M	−	B2	+	−

^aTwo identical isolates (designed by PFGE) obtained from one bird using nonselective isolation and selective isolation on MacConkey agar with cefotaxime (2 mg/liter),

^bThe strain was isolated by selective cultivation on MCA with nalidixic acid (20 mg/liter).

^cA, ampicillin; Ac, amoxicillin-clavulanic acid; C, chloramphenicol; Cf, cephalothin; Cip, ciprofloxacin; Gn, gentamicin; Na, nalidixic acid; S, streptomycin; Su, sulfonamides; Sxt, sulfamethoxazole-trimethoprim; T, tetracycline.

^dClass 1 integron.

^eND, not detected.