Evaluation of the Negative Predictive Value of Methicillin-Resistant Staphylococcus aureus Nasal Swab Screening in the Medical Intensive Care Units and Its Effect on Antibiotic Duration

Figures & data

Table

	MRSA infection (+)	MRSA infection (-)
MRSA (+) nasal swab	A	C
MRSA (-) nasal swab	B	D

Table 1 Demographic Data of Study Population

Characteristic		Teicoplanin n=280	Vancomycin n=58	All Patients n=338	P value
Male, no. (%)		175 (62.5)	39 (67.2)	214 (63.3)	0.495
Age, year (SD)		65.3±15.3	62.8±17.6	64.9±15.7	0.264
BMI, kg/m^Citation2 (SD)^#		23±4.7	22.9±4.4	23±4.6	0.903
APACHE II score (SD)*		26.17±9	25.3±9	26±9	0.484
Prior culture isolation of MRSA in the last 90 days, no. (%)		9 (3.2)	3 (5.2)	12 (3.6)	0.463
Receipt of parenteral antibiotics in the last 90 days, no. (%)		244 (87.1)	50 (86.2)	294 (87.0)	0.847
Recent hospitalization > 2 days in the last 90 days, no. (%)		243 (86.8)	46 (79.3)	289 (85.5)	0.141
Receipt of RRT in the last 90 days, no. (%)		54 (19.3)	31 (53.4)	85 (25.1)	<0.001
Recent influenza, no. (%)		20 (7.1)	5 (8.6)	25 (7.4)	0.695
CLCr>60 mL/min, no (%)		60 (21.4)	15 (25.9)	75 (22.2)	0.460
60≧CLCr>30 mL/min, no (%)		66 (23.6)	5 (8.6)	71 (21.0)	0.011
CLCr≦30 mL/min, no (%)		45 (16.1)	2 (3.4)	47 (13.9)	0.011
RRT, no. (%)		109 (38.9)	36 (62.1)	145 (42.9)	0.001
CVVH		65 (23.2)	18 (31.0)	83 (24.6)
HD		33 (11.8)	18 (31.0)	51 (15.1)
Transit to different RRT		11 (3.9)	0 (0.0)	11 (3.2)
Treatment days		4.2±3.8	5.7±7.3	4.4±4.6	0.283
Loading dose (mg/kg)		11.2±1.1	19.7±4.3

Note: ^#Missing data: 10 and 5 in teicoplanin and vancomycin group, respectively. *Missing data: 1 in teicoplanin group.

Abbreviations: BMI, body mass index; MRSA, methicillin-resistant Staphylococcus aureus; RRT, renal replacement therapy; CL_Cr, creatinine clearance; CVVH, continuous veno-venous hemofiltration; HD, hemodialysis; APACHE II, Acute Physiology and Chronic Health Evaluation II.

Figure 1 Flow chart.

Abbreviations: MRSA, methicillin resistant Staphylococcus aureus; MICU, medical intensive care unit.

Table 2 NPV, PPV, Sensitivity and Specificity of MRSA Nasal Screening by Types of Infections

	Pt, n	N+C+, n	N-C-, n	N+C-, n	N-C+, n	PPV, %	NPV, %	Sensitivity %	Specificity %
Whole screening cohort	277	15	252	6	4	71.4	98.4	78.9	97.7
Types of infections
Pneumonia	170	12	152	3	3	80.0	98.1	80.0	98.1
Bloodstream infection	18	3	14	1	0	75.0	100.0	100.0	93.3
Sepsis	50	1	46	2	1	33.3	97.9	50.0	95.8
Intra-abdominal infection	28	0	28	0	0	–	100.0	–	100.0
Skin and soft tissue infection	18	1	15	1	1	50.0	93.8	50.0	93.8
Urinary tract infection	5	0	4	1	0	0.0	100.0	–	80.0
Head and neck infection	10	1	9	0	0	100.0	100.0	100.0	100.0

Abbreviations: N, MRSA nasal screening; C, subsequent MRSA infection; MRSA, methicillin-resistant Staphylococcus aureus; Pt, patient; n, numbers; PPV, positive predictive value; NPV, negative predictive value.

Table 3 Patients with or without MRSA Nasal Screening in Medical Intensive Care Units^a

Characteristic		Without Screening n=32	With Screening n=122	All Patients n=154	P value
Male, no. (%)		20 (62.5)	86 (70.5)	106 (68.8)	0.385
Age, year (SD)		65.3±13.1	64.6±14.9	64.7±14.5	0.972
BMI, kg/m^Citation2 (SD)		21.5±5.3	22.9±5.9	22.6±5.8	0.135
APACHE II score (SD)		23.5±9.7	24.6±7.7	24.4±8.2	0.396
MRSA carrier		Not available	2 (1.6)
Prior culture isolation of MRSA in the last 90 days, no. (%)		1 (3.1)	4 (3.3)	5 (3.2)	1.000
Receipt of parenteral antibiotics in the last 90 days, no. (%)		31 (96.9)	107 (87.7)	138 (89.6)	0.195
Recent hospitalization > 2 days in the last 90 days, no. (%)		31 (96.9)	103 (84.4)	134 (87.0)	0.077
Receipt of RRT in the last 90 days, no. (%)		19 (59.4)	27 (22.1)	46 (29.9)	0.001
Recent influenza, no. (%)		1 (3.1)	15 (12.3)	16 (10.4)	0.195
Subsequent MRSA infection		0 (0)	0 (0)	0 (0)
CLCr > 60 mL/min, no (%)		4 (12.5)	41 (33.6)	45 (29.2)	0.019
60≧ CLCr >30 mL/min, no (%)		7 (21.9)	19 (15.6)	26 (16.9)	0.397
CLCr ≦ 30 mL/min, no (%)		1 (3.1)	21 (17.2)	22 (14.3)	0.047
RRT, no. (%)	CVVH	8 (25.0)	18 (14.8)	26 (16.9)	0.011
	HD	11 (34.4)	17 (13.9)	28 (18.2)
	Transit to different RRT	1 (3.1)	6 (4.9)	7 (4.5)
Treatment days		4.4±3.0	4.2±2.8	4.3±2.8	0.577

Note: ^aExclude patients with indications of glycopeptides use or death.

Abbreviations: BMI, body mass index; MRSA, methicillin-resistant Staphylococcus aureus; RRT, renal replacement therapy; CL_Cr, creatinine clearance; CVVH, continuous veno-venous hemofiltration; HD, hemodialysis; APACHE II, Acute Physiology and Chronic Health Evaluation II.

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