Serotype Distribution of Respiratory Adenoviruses in Egypt Determined By Serial Multiplex PCR

Abstract : Eighty-eight adenovirus (Ad) isolates and associated clinical data were collected from walk-in patients with influenza-like illness in Egypt (13 from Cairo, 75 from Alexandria) during routine influenza surveillance from 1999 through 2002. Ad diversity has not been well characterized in this region, and this sample set offered the opportunity to begin to define the locally important serotypes. Ad distributions are geographically variable, and serotype is clinically relevant because it determines vaccine efficacy and correlates strongly with both symptomology and epidemiological patterns. Serotypes were determined using several well-validated multiplex PCR protocols culled from the literature and supplemented with a few novel primer sets designed to identify rare types. The isolates included the common species B1 serotypes Ad3 and Ad7, the less common Ad11, and common species C serotypes Ad1, Ad2, and Ad5. Three isolates of the rare species B1 serotype Ad16, and two isolates that appear to be either variant Ad16s or closely related novel serotypes, were also identified. These variants, as well as the Ad11 isolates, were only firmly identified at the serotype level through the use of secondary methods (restriction enzyme analysis and sequencing, respectively), though serial PCR was able to identify them as rare serotypes of species B (not Ad3, 7, or 21). The primary method used in this study, serial multiplex PCR, is very rapid and requires very little equipment. The work presented here demonstrates the ease with which clinically relevant strain information about respiratory Ad isolates can be obtained without cumbersome neutralization tests.