Background: Salmonella enteritidis isolates have increased since 1982 from 20% to more than 70% in 1992 in Spain. Currently available phenotypic subtyping methods have a low discriminatory power. In order to improve the phage-typing discriminatory power of Alonso's method, new bacteriophages have been developed.
Methods: Wild bacteriophages were isolated from different waste waters. Lysogenic bacteriophages were induced with mitomycin C.
Results: We selected 7 wild and 2 lysogenic bacteriophages, considering their stability, reproducibility and discriminatory power. Ten phage-types were also described.
Conclusions: Using Simpson's index of diversity, the proposed scheme is more discriminatory power than Alonso's previously described one. It is necessary to compare it with other subtyping methods, like new molecular methods, before establishing its usefulness as a complementary marker.