Effect of donor-recipient relatedness on the plasmid conjugation frequency: a meta-analysis

BMC Microbiology

Table 2 Parameter estimates for the final multivariable linear mixed regression model for filter matings

	Included data points		Log₁₀(T / D)
	n	%	Mean	95% CI
Reference
	270	100	−5.38	−9.37	−1.40
*Relatedness toE. colidonor*
Same species	130	48.1	Reference
Same family	88	32.6	1.61	0.74	2.47
Same class	22	8.1	0.59	−1.03	2.22
Other class	30	11.1	0.64	−5.37	6.65
Recipient origin
Laboratory strain	116	43.0	Reference
Human	57	21.1	−0.86	−1.80	0.08
Dairy cattle	44	16.3	−2.16	−3.37	−0.94
Plant	16	5.9	−2.67	−6.75	1.41
Water	10	3.7	−6.10	−7.89	−4.31
Food	5	1.9	−2.29	−4.20	−0.39
Acidic drainage of a hot-spring	2	0.7	−1.37	−8.50	5.77
NR	20	7.4	−2.26	−4.56	0.03
Donor-to-recipient ratio
0.05–0.125	80	29.6	−2.59	−6.48	1.30
0.25–0.50	54	20.0	2.42	−0.83	5.68
1.00	124	45.9	Reference
3.00	10	3.7	−1.94	−8.31	4.44
NR	2	0.7	1.48	−3.50	6.46
Temperature (°C)
5	3	1.1	3.48	1.44	5.52
20–30	49	18.1	−0.15	−1.90	1.60
35–37	190	70.4	Reference
42–47	6	2.2	−0.03	−1.48	1.41
NR	22	8.1	1.06	−1.67	3.80
Mating time (h)
≤ 4	102	37.8	Reference
4.01–8.0	17	6.3	−1.80	−5.97	2.38
16–24	114	42.2	−3.63	−6.94	−0.31
30	27	10.0	−3.21	−7.70	1.29
48–72	10	3.7	−2.99	−10.78	4.81
Filter pore size (μm)
0.20–0.22	17	6.3	Reference
0.40–0.45	229	84.8	3.51	−1.35	8.38
NR	24	8.9	2.61	−2.59	7.82

CI confidence interval; D initial number of donors; n: number of data points; NR not reported; T number of transconjugants. The value given as ‘Reference’ denotes the mean log₁₀(T/D) if all variables are equal to their reference category, i.e., if the recipient is an E. coli laboratory strain, and the experiment is performed with a donor-to-recipient ratio of 1.00, a temperature of 35–37 °C and less than 4 h mating time on a filter with a 0.20–0.22 μm pore size. The values for the other categories list the differences from that overall mean

ISSN: 1471-2180