Serotyping and Phylogenetic analysis of Enteroviruses Isolated from Patients with Aspetic Meningitis

Lee, Jung Hee; Ahn, Byoung Yoon; Ban, Sung Hwan; Kim, Sang Hyun; Kim, Eui Chong

Abstract

BACKGROUND: The determination of serotype of enteroviruses is useful for the discrimination between sporadic and epidemic infections. The conventional serotyping method is time-consuming and labor-intensive. Recently, molecular method was introduced for the serotyping of enteroviruses. The aim of this study was to establish a method to isolate and analyze enteroviruses from various specimens utilizing molecular biological techniques and to determine which strains were phylogenetically related to clinical samples.
METHODS
Clinical samples in this study included 164 cerebrospinal fluid (CSF), 136 stool, 15 sera, 6 throat swab, 5 urine, and 4 sputa, which were obtained from hospitalized patients, primarily infants or children presenting symptoms of aseptic meningitis in 1998. RD cells were used for enterovirus isolation. RT-PCR was performed with RD cell lysate showing CPE. The primers 011 and 012 were used for the VP1 region, and the primers EN1 and EN2 for 5'-UTR. The nucleotide sequences of VP1 region were determined and analyzed with BLAST program.
RESULTS
Among 333 samples, only 23 samples produced CPE: 17 samples at first and six samples at the second blind passage. Fifteen isolates were related to coxsackievirus B2 two to echovirus 4, three to echovirus 6, and three to echovirus 18. All 23 viral isolates displayed a nucleotide sequence identity of 80-95%, compared with the reference serotypes. However, the identity was increased up to 93-100% when the VP1 region was translated into amino acids
CONCLUSIONS
Since CB2 type was 55% among enteroviral isolates, the CB2 was determined as the major causative serotype of enteroviral meningitis in 1998. CB2 type was emerged between June and July, EC4 and EC6 was limited to July, and EC18 was in August.