RT-nested PCR for the detection of enterovirus in biological samples from patients with suspected enteroviral infections.

In this study, we have tested a reverse transcription (RT) nested polymerase chain reaction (nPCR) for detection of enterovirus (EV) RNA in cerebrospinal fluid (CSF), serum samples, and conjunctival swabs (CS) from patients with suspected enterovirus infections. A specific 113-bp fragment was amplified using primers designed based on 5' non coding region of the enterovirus genome. The enterovirus RT-nPCR was able to detect 0.001 plaque forming unit (pfu)/ml. Since no PCR product was detected in each of the CSF, CS and serum samples from patients with proven-non-enterovirus viral infections, this method was found to be specific. EV RNA was detected in all 30 culture-confirmed CSF samples and yielded positive results in 5 out of 7 additional cases of culture-negative CSF samples with other evidences of enterovirus infection. Overall, EV RNA was detected in 95% of the patients with clinical diagnosis of viral central nervous system (CNS) disease and confirmed enterovirus infection. Furthermore, we were able to detect EV RNA in 24 (47%) out of 51 CSF samples from patients with clinical diagnosis of viral CNS disease and negative laboratory evidence of viral infection. The percentage of positive EV RNA detection in paired CSF and serum samples from 11 patients with an enterovirus isolate in CSF was 100% (11 of 11) and 73% (8 of 11), respectively. In addition, EV-specific IgM was detected in 64% (7 of 11) of the sera tested. The method was also tested against 136 samples of CS from patients with clinical diagnosis of acute hemorrhagic conjunctivitis. Ninety nine of them resulted positive (73%), while only 27 (20%) had been positive for viral culture. In summary, our study shows the importance of enterovirus RT-nPCR for the diagnosis of enterovirus associated disease in different kind of biological samples and different types of diseases.