Direct identification of human enterovirus serotypes in cerebrospinal fluid by amplification and sequencing of the VP1 region

BackgroundHuman enteroviruses (HEV) are a major cause of meningitis and other neurological disease. Identification of HEV serotypes in clinical cases is important for monitoring emergence of more pathogenic variants, epidemiological surveillance and investigating sources of infection. Serotype identification is currently problematic following the widespread adoption of polymerase chain reaction (PCR)-based methods for HEV detection in place of virus culture.ObjectivesTo develop a reliable, sensitive method to identify species A and B serotypes directly from cerebrospinal fluid (CSF) specimens.Study designA nested-PCR was used to amplify VP1 region sequences of HEV species A and B, that enabled unambiguous serotype identification by comparison with reference strains.Results62 from 64 diagnostic CSF samples collected over a 19-month study period were successfully amplified (97% sensitivity), compared with 9/22 (41%) identified by virus culture of co-referred faecal and throat swab samples. Among these, 60 samples contained species B and 2 samples contained species A serotypes (coxsackievirus A6 and enterovirus 71) were identified. Rapid changes in serotype frequencies and diversity were observed; echovirus (E) type 9 infections predominated in early 2007, to be replaced by E30 later in the year and followed by a diverse range of eight different species B serotypes in 2008.ConclusionsThe availability of a simple and rapid method for identification of serotypes and individual HEV strains or clusters directly from CSF will be of substantial value in surveillance, understanding more about serotype-associated differences in disease and monitoring the global spread of pathogenic variants such as enterovirus 71.