Identificação de sorotipos de adenovírus em aspirados de nasofaringe de crianças, com doença respiratória aguda, atendidas em Uberlândia, MG

Abstract

Background: Adenoviruses (AdVs) are important cause of acute respiratory disease (ARD), gastroenteritis, conjunctivitis and urinary infections in humans. Objectives: Detection of AdVs by immunofluorescence assay (IFA) and by polymerase chain reaction (PCR) in nasopharyngeal aspirates of children less than 5 years old presenting ARD in Uberlândia, MG, as well as, comparison of two PCR assays and identification of serotypes that circulated in this region. Study Design: A total of 468 clinical specimens was collected from November 2000 to April 2007 and tested by IFA for adenovirus detection and other viruses. After that, the DNA of the 126 in natura negative/inconclusive samples by IFA which were also negative for rhinovirus by RT-PCR, were extracted by Trizol® and tested by PCRAraújo (Araújo et al, 2001) for adenovirus detection. The positive specimens for adenovirus were inoculated into HEp-2 and A-549 continuous cell lineages. In addition, the DNA of either, in natura samples and cell culture-scrapped samples, were extracted by using the QIAmp DNA Mini Kit (QIAGENTM Valencia, CA) and tested again by PCRAraujo and by PCRAllard (Allard et al., 2001) in order to compare the sensitivity/specificity of both tests. In addition, the serotypes were identified from the nucleotide sequencing of PCR products positive for adenovirus. Results: From the 468 samples, 33 (7.1%) were positive for AdVs, 14 by IFA and 19 by PCRAraujo. From the 32 specimens inoculated in cell culture, it was possible to isolate AdVs in 16. The comparison of the results obtained from the DNA of the 33 in natura samples extracted by the QIAmp DNA Mini Kit (QIAGENTM Valencia, CA) showed that the sensibility of PCRAraujo was a little higher than PCRAllard (92.9% and 90.0%, respectively). However, the first PCR presented a lower specificity than the second one (57.9% and 91.3%, respectively). The serotype AdV2 was detected in almost 60.0% (7/12) of those identified. Conclusions: AdVs were detected in 7.1% of the clinical samples in children with ARD throught the combination of two methods, IFA and PCR. The analysis of the sensibility and specificity of the two PCR assays, showed that PCRAllard presented a little lower sensibility than PCRAraujo and higher specificity. The serotype AdV2 was identified in 7 of the 12 AdVs sequenced samples.