TABLE 2.

Results of liquid mating conjugation of S. sonnei isolates^a

Isolate no.b	Resistance profilec	Transconjugant resistance profilec	Selective agard	Size (kb) of transconjugant plasmid(s)
3331Ab	ASSu	ASSuNa	A + Na	2,12, and 48
3331Ab	ASSu	ANa	A + Na	48
3599Ab	A	ANa	A + Na	11 and 45
CK2Bi	ASSuTTm	ASuTNa	A + Na	5 and 60
3219Ab	ASuTm	ANa	A + Na	33
3219Ab	ASuTm	ASuTmNa	Tm + Na	47
D3B3k	SSuTTm	SSuTNa	T + Na	60

^aNo transconjugants were obtained with isolate 3331, CK2, or D3 when streptomycin (30 mg/ml) and nalidixic acid (30 μg/ml) were used. No transconjugants were obtained with isolate CK2 or D3 when Mueller-Hinton agar with nalidixic acid (30 μg/ml) and trimethoprim (5 μg/ml) were used.

^bSuperscript letters indicate the PFGE type (upper case letters) and plasmid profile pattern (lowercase letters) for each strain.

^cThe resistance profiles are represented by the abbreviations for the antimicrobial agents to which the isolate tested was resistant: A, ampicillin; S, streptomycin; Su, sulfonamides; T, tetracycline; Tm, trimethoprim.

^dIsolates were selected on Tryptone soya agar with nalidixic acid (30 μg/ml) and ampicillin (100 μg/ml) (A + Na) or tetracycline (20 μg/ml) (T + Na) or Mueller-Hinton agar with nalidixic acid (30 μg/ml) and trimethoprim (5 μg/ml) (Tm + Na).