TABLE 3.

Overview of maximum transfer frequencies for different mating pairs and incubation times for conjugation experiments in biofilm

Mating pair (donor→recipient)	Mating time (h)	Transfer frequency ata:
		25°C	30/37°Cb
E. coli 1292(IncK)→E. coli 6927-5	4	NA	NTD
	24	3 × 10−6	5 × 10−4
	48	3 × 10−6	8 × 10−2
E. coli 2798(IncI1)→E. coli 6927-5	4	NA	4 × 10−5
	24	NTD	4 × 10−3
	48	NTD	2 × 10−2
E. coli 1292(IncK)→S. marcescens 3306	4	NA	NTD
	24	NTD	NTD
	48	NTD	NTD
E. coli 1292(IncK)→S. marcescens 3307	4	NA	NTD
	24	NTD	NTD
	48	NTD	7 × 10−6
S. marcescens 3306 transconjugant (IncK)→E. coli 6927-5	4	NA	9 × 10−6
	24	2 × 10−6	2 × 10−5
	48	NTD	3 × 10−4
S. marcescens 3307 transconjugant (IncK)→E. coli 6927-5	4	NA	1 × 10−5
	24	2 × 10−5	6 × 10−4
	48	9 × 10−5	2 × 10−3
S. marcescens 3307 transconjugant (IncK)→S. proteamaculans 5685	4	NA	NTD
	24	NTD	NTD
	48	NTD	5 × 10−7

^aThe transfer frequencies are calculated as the total number of transconjugants (T) divided by the total number of recipients (R). NTD, no transconjugants detected, transfer frequency of <5 × 10⁻⁷; NA, not applicable.

^b30°C was applied for all matings involving Serratia spp., while 37°C was applied for matings involving E. coli only.