Background: While commercial enzyme immunoassays (EIA) intended for the detection of adenovirus in fecal specimens are widely used, there are no rapid, convenient, and sensitive commercial tests available for the detection of adenoviruses in respiratory and conjunctival specimens. The applicability of EIA for the detection of adenovirus in stool and throat samples was investigated. One-day rapid culture assay (RCA) for the detection of adenovirus in respiratory and conjunctival specimens was developed and evaluated.
Patients and methods: Stool samples from patients with gastroenteritis were tested by adenovirus EIA and by cell culture using human embryonic lung cells (HEL) and Graham 293 cells. Blood and stool samples from two BMT patients were also tested for adenovirus by PCR for at least 6 months. Throat specimens from patients with respiratory infections and conjunctival specimens were used for the evaluation of 1-day RCA compared with conventional adenovirus isolation in Graham 293 cells.
Results: A total of 3,860 stool samples were tested by EIA Ridascreen, 8,169 by Novitec, and 2,218 by ProSpectT yielding 135 (3.5%), 308 (3.7%), and 77 (3.5%) positive results, respectively. From 305 Ridascreen- and 340 Novitec-negative stool samples, adenoviruses were isolated in three (0.9%) and eight (2.4%) cases, respectively, including two patients undergoing BMT. Multiple sequential stool samples from one BMT patient were repeatedly negative by EIA, but positive by PCR and cell culture. Graham 293 cells were better suited for isolation of adenovirus than HEL. EIA proved unreliable for detecting adenovirus in throat swabs. The sensitivity and specificity of RCA in throat swabs were 90% (37/41) and 100% (64/64), respectively, and 76% (16/21) and 100% (132/132) in conjunctival specimens, respectively.
Conclusions: Generally, EIA is sufficiently sensitive for the diagnosis of adenovirus-associated diarrhea. However, it may not be sensitive enough to detect adenovirus in immunocompromised patients undergoing BMT and shedding very few viral particles in stools. Thus, in such cases, a more sensitive assay, such as PCR, is recommended. Furthermore, EIA is not sufficiently sensitive for the reliable detection of adenoviruses in throat swabs. One-day RCA may be useful for the detection of adenoviruses in respiratory and conjunctival specimens.