title: Genotypic diversity and mixed infection in newborn disease and hearing loss in congenital cytomegalovirus infection.
abstract: BACKGROUND
  Congenital cytomegalovirus (cCMV) is a common congenital infection and a leading nongenetic cause of sensorineural hearing loss (SNHL). CMV exhibits extensive genetic variability, and infection with multiple CMV strains (mixed infection) was shown to be common in congenital CMV. The role of mixed infections in disease and outcome remains to be defined.
  
  
  METHODS
  Genotyping of envelope glycoproteins, UL55 (gB), UL73 (gN) and UL75 (gH), was performed on saliva specimens of 79 infants from the ongoing CMV and Hearing Multicenter Screening (CHIMES) Study and on blood and urine specimens of 52 infants who participated in natural history studies at the University of Alabama at Birmingham. Genotyping of UL144 and US28 was also performed in the CHIMES cohort. The association of individual genotypes and mixed infection with clinical findings at birth and SNHL was examined.
  
  
  RESULTS
  Thirty-seven of 131 infants (28%) were symptomatic at birth and 26 (20%) had SNHL at birth. All known genotypes of UL55, UL75, UL73 and US28 were represented, and no particular genotype was associated with symptomatic infection or SNHL. UL144 subtype C was more common in symptomatic infants but not associated with SNHL. Mixed infection was observed in 59 infants (45%) and not associated with symptoms (P = 0.43) or SNHL at birth (P = 0.82). In the cohort of 52 infants with long-term hearing outcome, mixed infection at birth was not predictive of SNHL.
  
  
  CONCLUSIONS
  Mixed infection is common in infants with congenital CMV but is neither associated with symptomatic infection nor associated with SNHL.
authors.affiliation: From the *Department of Pediatrics, †Department of Epidemiology, ‡International Health, and §Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Pati
authors.forename: Swetha
authors.initials: S
authors.lastname: Pinninti
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Novak
authors.forename: Nazma
authors.initials: N
authors.lastname: Chowdhury
authors.forename: Raj K
authors.initials: RK
authors.lastname: Patro
authors.forename: Karen
authors.initials: K
authors.lastname: Fowler
authors.forename: Shannon
authors.initials: S
authors.lastname: Ross
authors.forename: Suresh
authors.initials: S
authors.lastname: Boppana
mesh_terms: D015331:Cohort Studies; D060085:Coinfection; D003587:Cytomegalovirus / Q000235:genetics* / Q000302:isolation & purification; D003586:Cytomegalovirus Infections / Q000151:congenital* / Q000821:virology*; D005260:Female; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000151:congenital* / Q000821:virology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012463:Saliva / Q000821:virology; D019562:Viral Load