Molecular epidemiological study of Salmonella enterica serovar paratyphi B infections imported from Turkey to Western Norway.

During the summer of 1999, several Norwegian tourists returning from Turkey became ill as a result of Salmonella enterica serovar paratyphi B (S. paratyphi B) infection. We examined the S. paratyphi B isolates from 14 of these patients (10 from blood cultures, 4 from stool specimens) who were admitted to 2 hospitals in Bergen, Norway during August and September 1999. Moreover, during the same period, a laboratory technician working at 1 of these hospitals was admitted with S. paratyphi B septicemia and was included in the study. Using repetitive-sequence-based PCR (rep-PCR) with 2 primer pairs (ERIC and REP), pulsed-field gel electrophoresis and phage typing we found that the laboratory technician was infected with the same S. paratyphi B clone as the 14 tourists. The discriminatory capacity of the rep-PCR method and pulsed-field gel electrophoresis was examined using S. paratyphi B strains from the outbreak and from other geographical locations. We conclude that a combination of rep-PCR with the ERIC primer pair and phage typing was useful in discriminating between the epidemic isolates and epidemiologically unrelated isolates from S. paratyphi B infections and that the laboratory technician was most likely infected while handling patient samples or bacterial cultures from the Turkish tourists.