Combining cell lines to optimize isolation of human enterovirus from clinical specimens: report of 25 years of experience.

Cell culture is still the gold standard for the diagnosis of human enteroviruses (HEVs) although molecular techniques are required for detection of some serotypes. Due to the diversity of HEVs, a single cell line is not susceptible to all serotypes, and several lines are required to optimize the isolation of HEVs. In this study, the results of HEV isolation during the last 25 years are reported. A total of 1,192 HEVs were isolated and isolation rates varied depending on the cell line used. MRC5 cells yielded the best results (70.7%), followed by A549 cells (52.6%), RD cells (37.5%), and HEp-2 cells (29.7%). A total of 521 HEVs were characterized, and HEV-B was the most frequent species (81%). Polioviruses (PV) and HEV-A were isolated less frequently (17% and 1%, respectively). None of the cell lines detected all the enteroviruses. MRC5 cells were the most susceptible for isolation of echoviruses (85.7%) and PVs (85.4%), whereas HEp2 was the most susceptible for Coxsackieviruses B (82.6%). Some serotypes were isolated in one cell line only. 40.5% of echoviruses were isolated in MRC5 cells whereas 42.3% and 23.9% of Coxsackieviruses B were isolated in RD cells and HEp2 cells, respectively. Although A549 cells did not achieve the best performance for any enterovirus serotypes, they isolated 52.6% of the total HEVs. In view of these results, MRC5 cells, A549 cells, and RD cells should be combined to optimize isolation of HEVs.