The Lim Benyesh-Melnick antiserum pools for serotyping human enterovirus cell culture isolates-still useful, but may fail to identify current strains of echovirus 18

Neutralisation tests are often used as a second line method of serotyping human enterovirus cell culture isolates after failure of indirect immunofluorescence. We reviewed the results of 85 consecutive neutralisation tests performed routinely on presumptive enterovirus isolates using the Lim Benyesh-Melnick antiserum pools after failure of immunofluorescence on most of them, in order to assess the value of these antiserum pools. Confirmation of serotype was determined by partial VP1 genome sequencing. Forty isolates were serotyped successfully and 45 isolates were untypable by the LBM pools, although 16 of the latter would not be expected to be typable by this means. Of eighteen echovirus 18 isolates tested, only two were typable by neutralisation. Of 15 coxsackievirus A16 isolates only nine were typable by neutralisation. Neutralisation with the LBM pools remains a useful second line method of serotyping human enteroviruses despite difficulties with at least two serotypes.