Emergence of multidrug-resistant Salmonella enterica serotype Typhimurium phage-type DT104 among salmonellae causing enteritis in Israel

The relative frequency of salmonella strains isolated from hospitalized and non-hospitalized patients in Southern Israel changed during the period, 19 94-6. Salmonella enterica serotype Typhimurium definitive phage-type 104 (D T104) appeared in Israel in 1994 and became the most prevalent strain in 19 96. An outbreak of enteritis due to Salmonella enterica serotype Agona occu rred in Israel, in October 1994 and lasted for 4 months. The relative frequ ency of Salmonella enterica serotype Enteritidis remained almost constant d uring these years, with seasonal fluctuations only. The importance of the increase in the prevalence of Typhimurium DT104 has b een the epidemic spread of a multiresistant strain of R-type ACT (A, ampici llin; C, chloramphenicol; T, tetracycline) belonging to this phage-type. Si nce 1995 the frequency of Typhimurium DT104 isolates that possess, in addit ion to the above R-type, a chromosomally encoded resistance to the quinolon e drug, nalidixic acid, increased tenfold. In 1996, 27 % of the Typhimurium DT104 isolates were of R-type ACTN. S. Enteritidis exhibited over 95 % sus ceptibility to at least eight of the most commonly used antibiotic drugs, a nd none of the isolates was resistant to quinolone or fluoroquinoline.