The spread and antibiotic resistance of Salmonella enterica serotype typhimurium DT104 in Hungary

Comparison of phage types (PTs) determined by Felix and Callow's and Anderson's methods was performed testing 99 human strains of S. enterica serotype Typhimurium (S. typhimurium) isolated in Hungary. PT2 and PT2c--according to Felix-Callow--corresponded with Anderson's DT104 in case of 39 strains out of 40. Among 59 isolates belonging to other Felix-Callow's PTs only one strain was found which was DT 104. Similar unambiguous equalities could not be established between any other PTs comparing the two methods. The PTs of 17,877 human strains isolated between 1988 and 1999 were determined using Felix-Callow's method. On the basis of the above equality the emergence of DT104 could be followed retrospectively by means of the rate of PT2 and PT2c. The increase of DT104 began already in 1989, emerging first PT2c then PT2. It predominated since 1991 and it reached its maximum (78.3%) in 1999. The incidence of multiresistance among one of the groups of DT104 strains (Felix-Callow's PT2) was significantly higher in 1998 than the average of non-DT104 strains. The predominant R-type was ACST.