Multidrug-resistant Salmonella Typhimurium in four animal facilities

Abstract

In 1999 and 2000, 3 state health departments reported 4 outbreaks of gastrointestinal illness due to Salmonella enterica serotype Typhimurium in employees, clients, and client animals from 3 companion animal veterinary clinics and 1 animal shelter. More than 45 persons and companion animals became ill. Four independent investigations resulted in the testing of 19 human samples and >200 animal samples; 18 persons and 36 animals were culture-positive for S. Typhimurium. One outbreak was due to multidrug-resistant S. Typhimurium R-type ACKSSuT, while the other 3 were due to multidrug-resistant S. Typhimurium R-type ACSSuT DT104. This report documents nosocomial transmission of S. Typhimurium and demonstrates that companion animal facilities may serve as foci of transmission for salmonellae between animals and humans if adequate precautions are not followed.

Figure 1

Date of death among cats and week of illness onset among human case-patients, Minnesota, 1999.

Figure 2

Pulsed-field gel electrophoresis patterns of human and feline isolates from Minnesota outbreak,1999. Lanes 1, 2, 8, 14, and 15 contain Xbal-digested DNA from the standard strain H9812; lanes 3, 4, 9, and 10 contain human isolates; lanes 5–7, and 11–13 contain feline isolates. Lanes 3–7 were digested with Xbal and lanes 9–13 with Blnl.

Figure 3

Pulsed-field gel electrophoresis patterns associated with the Washington state outbreaks, 1999 and 2000. Lanes A and F are standards; lane B is cat, clinic B; lane C is cat, clinic C; lanes D and E are human isolates.(For confidentiality reasons, Washington Department of Health did not identify which human isolates were from which outbreak.) Human and cat isolates are indistinguishable.