Detection and differentiation of the gene for toxin co-regulated pili (tcpA) in Vibrio cholerae non-O1 using the polymerase chain reaction.

The polymerase chain reaction has been used to differentiate the gene which encodes the toxin co-regulated pili (tcpA) of the El Tor and classical biotypes of Vibrio cholerae O1. The same PCR primers were applied to strains belonging to non-O1 serogroups that produced cholera toxin. The size of fragment amplified was either identical to the tcpA of biotype El Tor (471 bp) or to the tcpA of biotype classical (617 bp). All strains belonging to the novel epidemic serogroup O139 generated a 471-bp fragment identical to El Tor tcpA. The present study suggests that there may be an association between non-O1 serogroup and tcpA type.