Real-Time Detection of Influenza A, Influenza B, and Respiratory Syncytial Virus A and B in Respiratory Specimens by Use of Nanoparticle Probes | Journal of Clinical Microbiology

DOI: 10.1128/JCM.01118-10

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TABLE 1.

Analytical sensitivities of VRNAT and RVNAT _SP (limits of detection)

Virus strain	LoD of:
Virus strain	VRNAT	RVNAT _SP
Influenza A virus strains
Influenza A/Wisconsin/67/05 (H3N2)	2 TCID₅₀ ^a/ml	2 TCID₅₀/ml
Influenza A/New Caledonia/20/99 (H1N1)	50 TCID₅₀/ml
Influenza A/Port Chalmers/1/73 (H3N2)	50 TCID₅₀/ml
Influenza A/Wisconsin/629/2009 (2009 H1N1)	50 TCID₅₀/ml
Influenza B virus strains
Influenza B/Florida/04/2006	60 TCID₅₀/ml	50 TCID₅₀/ml
Influenza B/Lee/40	0.01 EID₅₀ ^b/ml
Influenza B/Hong Kong/5/72	0.05 EID₅₀/ml
RSV A strains
A2	10 TCID₅₀/ml
Long	10 TCID₅₀/ml	10 TCID₅₀/ml
RSV B strains
B-1 Wild Type (B WV/14617/85)	2 TCID₅₀/ml	2 TCID₅₀/ml
Wash/18537/62	0.5 TCID₅₀/ml
9320	0.05 TCID₅₀/ml

↵ a TCID₅₀, 50% tissue culture infective dose.
↵ b EID₅₀, 50% embryo infectious dose.

TABLE 2.
Comparison of VRNAT to culture/DFA methods for influenza virus and RSV detection
Test method No. of positive results^a
Total Influenza A virus Influenza B virus RSV
VRNAT 322 (119) 181 (58^b) 40 (9^c) 101 (52^d)
Culture/DFA 203 123 31 49
↵ a Values in parentheses are numbers of additional positive results by VRNAT.
↵ b All were positive by sequencing.
↵ c Four were positive by sequencing.
↵ d Forty-six were positive by sequencing.

TABLE 3.

Clinical performance of VRNAT compared to culture/DFA methods^a

Specimens considered and discord resolution status	Sensitivity	Specificity	PPV^b	NPV^c
All specimens
Before discord resolution	96.6	93.6	60.9	99.6
After discord resolution	98.0	96.5	91.6	99.2
Influenza A virus positive
Before discord resolution	99.2	90.1	67.4	99.8
After discord resolution	100.0	99.8	99.2	100.0
Influenza B virus positive
Before discord resolution	96.8	98.5	75.0	99.9
After discord resolution	100.0	99.1	83.3	100.0
RSV positive
Before discord resolution	89.8	91.5	43.6	99.2
After discord resolution	91.7	98.4	80.0	99.4

↵ a A total of 720 nasopharyngeal swab specimens were analyzed using culture/DFA and VRNAT assays to detect influenza A and B virus and RSV. Discordant results were resolved using bidirectional sequencing.
↵ b PPV, positive predictive value.
↵ c NPV, negative predictive value.

TABLE 4.
Comparison of manual VRNAT and automated RVNAT _SP systems for detection of influenza A virus, influenza B virus, and RSV
RVNAT _SP result No. of specimens with VRNAT result of: Total
Positive Negative
Positive 191 0 191
Negative 4^a 363 367
Total 195 363 558
↵ a All 4 specimens that initially gave a negative result on the RVNAT _SP were positive upon repeat assay.

Additional Files

Tables

Supplemental material

Files in this Data Supplement:

Supplemental file 1 - Tables S1 (Respiratory virus reference strains used for sequence comparison) and S2 (Analytical specificity and cross-reactivity of the VRNAT)
Zipped MS Word document, 11K.

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KEYWORDS

influenza A virus

Influenza B virus

Oligonucleotide Probes

Respiratory Syncytial Viruses

respiratory tract infections

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