Distribution characteristics of virulence genes of Staphylococcus aureus causing bloodstream infections

doi:10.3969/j.issn.1673-8640.2026.08.013

Abstract

Abstract:

Objective To understand the distribution characteristics of virulence genes carried by different types of Staphylococcus aureus causing bloodstream infections in adults and children. Methods A total of 91 Staphylococcus aureus isolates from blood culture samples，preserved in the Microbiology Laboratory of Xinhua Hospital of Shanghai Jiao Tong University School of Medicine，were collected，including 44 methicillin-resistant Staphylococcus aureus（MRSA） and 47 methicillin-susceptible Staphylococcus aureus（MSSA）. All the isolates were determined by multilocus sequence typing（MLST），and they were determined for 25 virulence genes，and the carriage of virulence genes among different Staphylococcus aureus ST types was analyzed in combination with clinical data from infected patients. Results The determination rates of hemolysin genes hla and hlg，as well as the adhesion-related gene ica，were all 100.0% among the 91 Staphylococcus aureus isolates，and etb and see genes were not determined. Totally，5 adhesion-related genes had determination rates >50%. The average number of virulence genes carried by ST1，ST5 and ST22 was higher than that of ST398 and ST188（P<0.001）. The determination rates of PVL，clfA and clfB in the isolates from children were higher than those from adults（P values were <0.001，0.037 and 0.039，respectively），and the determination rates of fnbA，sdrC，sdrD and sdrE in the isolates from adults were higher than those from children（P values were 0.027，0.033，0.003 and 0.002，respectively）. The determination rates of tst，sdrE，sea and sec in MRSA were higher than those in MSSA（P values were 0.006，0.039，0.042 and <0.001，respectively），while the determination rates of can and clfB in MSSA were higher than those in MRSA（P values were <0.001）. The determination rate of seg in the intensive care unit（ICU） was higher than that in non-ICU（P=0.04）. The determination rate of fnbB in Staphylococcus aureus from implantation infections was higher than that in Staphylococcus aureus from non-implantation infections（P=0.003）. Conclusions Staphylococcus aureus causing bloodstream infections carry a number of virulence genes，and the carriage of virulence genes by different ST types，populations and inpatient wards of Staphylococcus aureus shows significant differences.

Key words: Staphylococcus aureus, Virulence gene, Adhesion factor, Hemolytic toxin, Enterotoxin, Bloodstream infection

CLC Number:

R378.1

YU Jiajia, LIU Ying. Distribution characteristics of virulence genes of Staphylococcus aureus causing bloodstream infections[J]. Laboratory Medicine, 2026, 41(8): 799-805.

Figures/Tables 6

References 26

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ST型别	CC克隆群^①	株数/株	平均携带毒力基因数/个
398		13	7.8
59		10	8.7
88		7	9.4
1	1	6	12.7
22	22	6	12.0
6	5	5	9.6
764	5	5	10.8
188	1	4	7.8
630	8	3	10.0

ST型别	CC克隆群^①	株数/株	平均携带毒力基因数/个
398		13	7.8
59		10	8.7
88		7	9.4
1	1	6	12.7
22	22	6	12.0
6	5	5	9.6
764	5	5	10.8
188	1	4	7.8
630	8	3	10.0

项目	PVL	tst	eta	etb	hla		hlb		hlg		icaA		cna		clfA		clfB		fnbA		fnbB
总体	12.1	15.4	1.1	0	100		83.5		100.0		100.0		48.4		46.2		75.8		45.1		31.9
成人	3.3	20.0	0	0	100		86.7		100.0		100.0		48.3		38.3		68.3		53.3		35.0
儿童	29.0	6.5	3.2	0	100		77.4		100.0		100.0		48.4		61.3		90.3		29.0		25.8
χ²值	12.703	2.882					1.270						0.000		4.334		4.259		4.876		0.796
P值	<0.001	0.090	0.341				0.260						0.996		0.037		0.039		0.027		0.372
项目	sdrC	sdrD	sdrE	sea		seb		sec		sed		see		seg		seh		sei		sej
总体	69.2	62.6	76.9	18.7		16.5		18.7		4.4		0		40.7		6.6		39.6		4.4
成人	76.7	73.3	86.7	21.7		13.3		25.0		5.0		0		46.7		8.3		46.7		5.0
儿童	54.8	41.9	58.1	12.9		22.6		6.5		3.2		0		29.0		3.2		25.8		3.2
χ²值	4.572	8.601	9.420	1.033		1.270		3.489		0.000				2.634		0.235		3.720		0.000
P值	0.033	0.003	0.002	0.464		0.260		0.062		1.000				0.105		0.628		0.054		1.000

项目	PVL	tst	eta	etb	hla		hlb		hlg		icaA		cna		clfA		clfB		fnbA		fnbB
总体	12.1	15.4	1.1	0	100		83.5		100.0		100.0		48.4		46.2		75.8		45.1		31.9
成人	3.3	20.0	0	0	100		86.7		100.0		100.0		48.3		38.3		68.3		53.3		35.0
儿童	29.0	6.5	3.2	0	100		77.4		100.0		100.0		48.4		61.3		90.3		29.0		25.8
χ²值	12.703	2.882					1.270						0.000		4.334		4.259		4.876		0.796
P值	<0.001	0.090	0.341				0.260						0.996		0.037		0.039		0.027		0.372
项目	sdrC	sdrD	sdrE	sea		seb		sec		sed		see		seg		seh		sei		sej
总体	69.2	62.6	76.9	18.7		16.5		18.7		4.4		0		40.7		6.6		39.6		4.4
成人	76.7	73.3	86.7	21.7		13.3		25.0		5.0		0		46.7		8.3		46.7		5.0
儿童	54.8	41.9	58.1	12.9		22.6		6.5		3.2		0		29.0		3.2		25.8		3.2
χ²值	4.572	8.601	9.420	1.033		1.270		3.489		0.000				2.634		0.235		3.720		0.000
P值	0.033	0.003	0.002	0.464		0.260		0.062		1.000				0.105		0.628		0.054		1.000

项目	PVL	tst	eta	etb	hla		hlb		hlg		icaA		cna		clfA		clfB		fnbA		fnbB
总体	12.1	15.4	1.1	0	100.0		83.5		100.0		100.0		48.4		46.2		75.8		45.1		31.9
MRSA	6.8	27.3	0	0	100.0		88.6		100.0		100.0		27.3		40.9		59.1		54.5		29.5
MSSA	17.0	4.3	2.1	0	100.0		78.7		100.0		100.0		68.1		51.1		91.5		36.2		34.0
χ²值	1.370	7.565					1.622						15.157		0.943		11.305		3.100		0.212
P值	0.242	0.006	1.000				0.203						<0.001		0.332		<0.001		0.078		0.645
项目	sdrC	sdrD	sdrE	sea		seb		sec		sed		see		seg		seh		sei		sej
总体	69.2	62.6	76.9	18.7		16.5		18.7		4.4		0		40.7		6.6		39.6		4.4
MRSA	65.9	72.7	86.4	27.3		22.7		36.4		4.5		0		45.5		11.4		43.2		4.5
MSSA	72.3	53.2	68.1	10.6		10.6		2.1		4.3		0		36.2		2.1		36.2		4.3
χ²值	0.441	3.706	4.277	4.139		2.412		15.353		0.000				0.812		1.827		0.467		0.000
P值	0.507	0.054	0.039	0.042		0.120		<0.001		1.000				0.368		0.177		0.494		1.000