Detection of cytomegalovirus DNA in dried blood spots of Minnesota infants who do not pass newborn hearing screening.
BACKGROUND
Up to 15% of infants with asymptomatic congenital cytomegalovirus (CMV) infection will experience some degree of sensorineural hearing loss. Many infants who fail newborn hearing screening (NHS) are likely to have congenital CMV infection, but may escape definitive virologic identification because diagnostic evaluation may not commence until several weeks or months of age, making differentiation between congenital and postnatal CMV infection difficult. Early diagnosis linking virologic identification of congenital CMV infection to infants failing NHS may improve diagnostic precision and enhance opportunities for therapeutic intervention.


METHODS
The goal of this study was to compare newborn dried blood spots from Minnesota infants who had failed NHS, and were designated for referral, with control infants who passed NHS, for the presence of CMV DNA by real-time PCR, using hybridization probes for the CMV gene UL54.


RESULTS
Of 479 infants with a failed NHS (bilateral failure), 13 had CMV DNA present in the blood spot (2.7%). This compared with only 2/479 positive results from a control group of infants who passed the NHS (0.4%; P = 0.007, Fisher exact test). Comparisons of the glycoprotein B (gB) genotype as well as direct DNA sequencing of selected positives revealed that PCR positive samples represented unique clinical isolates. The mean viral load among the 15 positive samples was 1.6 x 10(3) genomes/microgram of total DNA.


CONCLUSIONS
Newborn bloodspot CMV screening by real-time PCR may be a useful and rapid adjunct to functional NHS and may enable more rapid etiologic diagnosis of sensorineural hearing loss in newborns.
Choi
K Yeon
KY
Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455-0374, USA.
Schimmenti
Lisa A
LA
Jurek
Anne M
AM
Sharon
Bazak
B
Daly
Kathy
K
Khan
Cindy
C
McCann
Mark
M
Schleiss
Mark R
MR
D016009:Chi-Square Distribution; D015331:Cohort Studies; D003587:Cytomegalovirus / Q000235:genetics / Q000302:isolation & purification*; D004279:DNA, Viral / Q000097:blood*; D003939:Diagnostic Techniques, Otological; D005260:Female; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000097:blood / Q000235:genetics / Q000821:virology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008910:Minnesota; D015997:Neonatal Screening; D016133:Polymerase Chain Reaction; D013048:Specimen Handling; D019562:Viral Load
D004279:DNA, Viral