[Identification and typing of adenovirus from acute respiratory infections in pediatric patients in Beijing from 2003 to 2012].

Adenovirus (ADV) is one of the most common causes of acute respiratory infections for infants and children. The objective of this study was to understand the prevalence of ADV in acute respiratory infections in infants and children in Beijing and the types of the circulating ADVs. Clinical specimens were collected from patients with acute respiratory infections in a consecutive period of 10 years from Jan 2003 to Dec 2012. ADVs were detected from the collected clinical specimens by tissue culture and/or immunofluorescence assay and typed by nested-PCR based on the sequence of hexon gene for ADV types 3 and 7. For those strains which could not be typed by the nest-PCR, the gene fragment was amplified by a universal primer pair for all ADV types from group A to F and the PCR products were sequenced directly and analyzed with sequence comparison. Out of 39214 clinical specimens collected, including 7198 throat swabs from outpatients and 32016 nasopharyngeal aspirates from hospitalized patients, 884 were ADV positive by tissue culture and/or immunofluorescence assay, the overall positive rate was 2.25% (884/39214). The positive rate of ADV from the hospitalized was 2.08% (665/32016), while from the outpatients was 3.04% (219/7198). The ADV positive rate for year 2010 was 3.69%, which was the highest among the 10 years. The types of the ADVs were tested for 848 out of the 884 patients by using the nest-PCR and sequence analysis. It was showed that AD3 was the most prevalent with the rate of 53.18% (451/848), followed by AD7 36.79% (312/848), AD2 3.78% (32/848), AD55 2.24% (19/848), AD1 2.0% (17/848), AD5 0.94% (8/848), AD14 0.47% (4/848), AD6 0.35% (3/848) and AD4 0.24% (2/848). AD3 was the most predominant in most of the years among these 10 years, except 2012, 2003 and 2007. AD7 was the most predominant in 2012, and AD3 and AD7 were co-circulated in 2003 and 2007. Among 26 ADV infected severe pneumonia cases with pulmonary failure, 23 (88.5%) were AD7 positive, while 12 ADV associated tonsillitis, 11 (91.7%) were AD 3. The ADV positive rates from age groups 0-3 years were higher than age groups older than 4 years. The ratio for ADV positive males to females was 1.9 to 1. Adenovirus is still an important pathogen of acute respiratory infection in infants and young children. Most of the ADV associated acute respiratory infections in children in Beijing from 2003 to 2012 were AD3 and AD7. Most of the severe lower respiratory infections were associated with AD7. AD55 generated by recombination of AD11 and AD14 emerged in 2006.