Comparison of two Salmonella enteritidis phage typing methods

In the last 10 years several phage typing methods were developed for Salmonella enteritidis, leading to confusion in the predominant phage types (PT) reported from different countries. We made comparative examinations on 1487 S. enteritidis strains isolated in Hungary in 1990-1991, using two phage-sets: a modified version of the method elaborated by László et al. (here in after Hungarian method) and the system of Ward et al. (here in after Colindale method). Typability of the strains was nearly the same: 98.0% and 98.3%, the isolates belonging to 18 and 19 phage types, respectively. The Hungarian method revealed 6 (1, 1c, 1b, 1d, 7, 18), the Colindale method 5 (1, 6, 8, 21, 26) frequent phage types. In Hungary PT 1 has been predominant since 1981 and using the Colindale method 64% belonged to this type; using the modified Hungarian method this type could be divided into PT 1, PT 1c, PT 1b and PT 1d. Other frequent phage types (PT 18, PT 7) were nearly identical with Colindale types PT 26 and PT 21.