. 2020 Mar 30;174(6):1–11. doi: 10.1001/jamapediatrics.2020.0132

Table 1. Colonization Events and Association With Interval SSTIs.

Colonization prevalence and frequency^a	All individuals (n = 540)		Index patients (n = 128)
Colonization prevalence and frequency^a	No. (%)^b	Positive samplings, median (IQR)	No. (%)^b	Positive samplings, median (IQR)	No. (%)^b	Positive samplings, median (IQR)
Any S aureus	420 (78)	2 (1-4)	100 (78)	2 (1-4)	320 (78)	2 (1-4)
MRSA^c	265 (49)	0 (0-2)	76 (59)	1 (0-2)	189 (46)	0 (0-1)
MSSA	286 (53)	1 (0-2)	65 (51)	1 (0-2)	221 (54)	1 (0-2)
Infecting strain^d	123 (23)	0 (0-1)	40 (31)	1 (0-1)	83 (20)	0 (0-1)
Strain persistence and degree	No. (%)^e	Persistence degree, median (IQR)^f	No. (%)^{^e}	Persistence degree, median (IQR)^f	No. (%)^e	Persistence degree, median (IQR)^f
Any S aureus	213 (39)	2 (1-3)	52 (41)	1.5 (1-2)	161 (39)	2 (1-3)
MRSA^c	109 (20)	1 (1-3)	33 (26)	1 (1-3)	76 (18)	1 (1-3)
MSSA	112 (21)	2 (1-2)	22 (17)	1 (1-2)	90 (22)	2 (1-2)
Infecting strain^d	48 (9)	2 (1-3)	19 (15)	1 (1-3)	29 (7)	2 (1-3)
Association with No. of interval SSTIs^g	ρ	P value	ρ	P value	ρ	P value
Colonization frequency
Any S aureus	0.11	.03	0.18	.07	0.09	.10
MRSA^{^c}	0.29	<.001	0.42	<.001	0.21	<.001
MSSA	−0.14	.005	−0.19	.06	−0.11	.06
Infecting strain^h	0.36	<.001	0.42	<.001	0.29	<.001
Strain persistence degree
Any S aureus	0.09	.07	0.18	.08	0.07	.18
MRSA^c	0.27	<.001	0.35	<.001	0.24	<.001
MSSA	−0.14	.003	−0.18	.07	−0.12	.03
Infecting strain^h	0.34	<.001	0.40	.001	0.28	<.001

Abbreviations: IQR, interquartile range; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-susceptible S aureus; SSTI, skin and soft tissue infection.

^{^a}

Eligible individuals for this analysis were those who underwent all 5 samplings (n = 540).

^{^b}

The number of individuals colonized at least once.

^{^c}

All MRSA, including infecting-strain MRSA.

^{^d}

The isolate recovered from the index patient’s enrollment infection (infecting strain) was available in 91 households; thus, the number for the all individuals (n = 312), index patients (n = 77), and household contacts (n = 235) columns was reduced in rows associated with the infecting strain.

^{^e}

The number of individuals colonized with the same strain at consecutive samplings at least once (persistence degree ≥1).

^{^f}

The median (IQR) is for individuals with persistence degree of 1 or greater.

^{^g}

Eligible individuals for this analysis were those who underwent all 5 samplings and were colonized at least once (420 overall, 100 index patients, and 320 household contacts). Spearman correlation test was used.

^{^h}

The infecting strain was available in 91 households; thus, the number for all individuals (n = 238), index patients (n = 63), and household contacts (n = 175) was reduced in rows associated with the infecting strain.