RESISTOTYPING OF CAMPYLOBACTERS - FULFILLING A NEED

A 9-month trial of a simple typing scheme for 'thermophilic' enteric c ampylobacter isolates at a large Public Health laboratory is described . Resistotyping was performed with six agents in a method modified by Bolton and colleagues from an earlier scheme, and biotyping was perfor med by a modified Lior scheme involving three tests. Reproducibility w as excellent in both schemes, with test variation <2%. Five household clusters and one larger presumptive milk-borne outbreak were identifie d in this scheme, and confirmed in pyrolysis mass spectrometry. The 32 8 isolates from new patients, excluding duplication from these cluster s, were divided into 35 resistotypes with the largest group comprising 22% of isolates. In combined bio- and resistotyping, 86 types were fo und, with the largest group comprising 9.5% of isolates. The results a re contrasted with salmonella sero- and phage-typing, where, on the sa me basis, the 176 isolates in the same period were divided into 40 gro ups, with the largest comprising 45% of isolates. Resistotyping, with or without additional biotyping, proved to be a convenient, simple, ra pid, highly discriminatory, reproducible and inexpensive method well s uited to use in local laboratories. It is a strong candidate for first -line national and local surveillance of campylobacter infections, ful filling a need for monitoring of this important cause of enteric disea se.