Epidemiological value of the gamma-glutamyltransferase test in Salmonella typhimurium

The simple and rapid method of Giammanco et al. (1980) has been used for the detection of the gamma-glutamyltransferase (gamma-GT) by means of a chromogenic substrate in 803 endemic and epidemic strains of Salmonella typhimurium from Southern Italy. About 20% of the strains have been proved gamma-GT negative. Both in endemic and epidemic isolates, negative and positive strains were respectively belonging to different phage types. The reported data suggest that the presence or absence of the gamma-GT in S. typhimurium is an epidemiological marker quickly and easily detectable by the described chromogenic test.