Background: To evaluate prospectively the efficacy of different clinical samples and cellular lines in the isolation of Enteroviruses from pediatric patients.

Methods: In the period july-1997 to july-1999 we analyze the samples of 102 pediatric patients (< 2 years old) with an unknown febrile etiology syndrome. After the process of decontamination the samples were inoculated in the MRC-5, Hep-2 and Vero cell lines by the shell-vial assay. After 2-3 days of incubation the monolayers were stained by a monoclonal antibody against VP1; then the strains were identified as Poliovirus, ECHO-virus or Coxsacke by specific antibodies.

Results: 96 clinical samples were studied (45 pharyngeal swabs, 28 feces, 13 cerebrospinal fluid, 5 bloods, 4 urines and one bronchoalveolar lavage). Enteroviruses were isolated in 48 patients (47%), corresponding to 60 clinical samples (62.5%). The enteroviruses were isolated in 75.5% of pharyngeal swabs, 71.4% of feces, 30.7% of cerebrospinal fluid, one blood (20%) and the bronchoalveolar lavage. 28 patients presented simultaneously both pharyngeal and rectal swabs; in this group the use of both samples permitted the isolation of Enteroviruses in 26 cases (92.8%). Of 60 Enteroviruses, 59 (98.3%) were isolated in the MRC-5 cell line, 23 (38.3%) in the Hep-2, and 14 (23.3%) in the Vero; the MRC-5 demonstrated a significant difference in the isolation of Enteroviruses compared with the other cell lines. The Enteroviruses were identified as 30 (50%) ECHO-virus, 15 (25%) as Poliovirus vaccine, 12 (20%) could not to be identified and in 3 cases (5%) no growth of virus was detected in the culture. The MRC-5 cell line was significatively superior to the other in the isolation of the different Enteroviruses.

Conclusions: To obtain the maximum diagnostic efficacy in front a patient with a possible infection by Enteroviruses, is necessary to use different clinical samples, specially the more related to the infection focci (cerebrospinal fluid or blood). The MRC-5 cell line has been the most efficace in the isolation of Enteroviruses independently of the type of clinical sample or the viral genus. The shell-vial assay is a good method for the isolation and identification of Enteroviruses isolated from clinical samples.