Comparison of mixed cell culture containing genetically engineered BGMK and CaCo-2 cells (Super E-Mix) with RT-PCR and conventional cell culture for the diagnosis of enterovirus meningitis

Abstract

Enteroviral meningitis has traditionally been diagnosed by cell culture. More recently, molecular techniques and shell vials with a mixture of human colon carcinoma and genetically engineered buffalo green monkey kidney cells (BGMK cells) (Super E-Mix) have been described. We compared the results of this new cell culture technique with two reverse transcriptase polymerase chain reaction (RT-PCR) techniques and conventional cell culture to assess the accuracy of these various methods. 2 ml of cerebrospinal fluid (CSF) was obtained from 72 patients with suspected viral meningitis. 600 microl was used for conventional cell culture and 200 microl was inoculated to each of two Super E-Mix vials. One vial was incubated for 24 h, then stained with pan-enterovirus antibody, and the other was examined for CPE daily for 5 days and stained when positive or at the end of incubation. The final aliquot (500 microl) was centrifuged at 25,000g, and the pellet in 140 microl of supernatant was used for ribonucleic acid (RNA) extraction and tested by commercial single-step (Chemicon, Temecula, CA) and two-step (Argene, Varilhes, France) RT-PCR methods. Conventional culture was 51% sensitive and 100% specific. The Super E-Mix was slightly higher (sensitivity 76%, specificity 100%). The Chemicon and Argene PCR methods had a sensitivity of 93% and 88% and specificity of 90% and 97%, respectively. The Super E-Mix procedure had greater sensitivity than conventional cell culture, but RT-PCR was the most sensitive technique with this type of specimen. The RT-PCR methods performed equally.