Multidrug- Resistant Salmonella enterica Serovar Infantis, Israel Ohad Gal-Mor, Lea Valinsky, Miriam Weinberger, Sara Guy, Joseph Jaffe, Yosef Ilan Schorr, Abraham Raisfeld, Vered Agmon, and Israel Nissan To determine whether rapid emergence of Salmonella enterica serovar Infantis in Israel resulted from an increase in different biotypes or spread of 1 clone, we characterized 87 serovar Infantis isolates on the genotypic and phenotypic levels. The emerging strain comprised 1 genetic clone with a distinct pulsed-ield gel electrophoresis proile and a com- mon antimicrobial drug resistance pattern. N ontyphoid Salmonella enterica (NTS) is a common cause of foodborne illnesses worldwide. In industrial- ized countries, S. enterica serovars Enteritidis and Typh- imurium are responsible for most NTS infections (1). In Israel, the distribution of NTS infections differs from the global epidemiology for NTS by having a larger represen- tation of serogroups C1 and C2 (serovars Virchow, Hadar, and Infantis) in addition to serovars Enteritidis and Typh- imurium (2,3). Analysis of annual trends of NTS infections in Israel during 1995–2009 shows a steady decrease in the inci- dence of these infections, from 86.9 cases/100,000 persons in 1995 to 31.4/100,000 in 2005. During this period, the predominant serovars were Enteritidis, Typhimurium, Vir- chow, and Hadar, followed by Infantis. Since 2006, annual incidence of NTS has started to increase, rising to 44.0 cases/100,000 persons in 2009. This trend coincided with a sharp increase in incidence of serovar. Infantis from 1.2 cases/100,000 persons in 2001 to 14.7/100,000 in 2009, a 12-fold rise (Figure 1, panel A). The proportion of sero- var Infantis increased from <10% of NTS in 1995–2005 to 34% in 2009 (Figure 1, panel B). Furthermore, this steep increase in serovar Infantis from clinical (human) sources correlated with an elevated frequency of serovar Infantis DISPATCHES 1754 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 11, November 2010 Author afiliations: Sheba Medical Center, Tel-Hashomer, Israel (O. Gal-Mor); Ministry of Health Laboratories, Jerusalem, Israel (L. Val- insky, S. Guy, J. Jaffe, Y.I. Schorr, A. Raisfeld, V. Agmon, I. Nissan); and Assaf Harofeh Medical Center, Zeriin, Israel (M. Weinberger) DOI: 10.3201/eid1611.100100 Figure 1. Salmonellosis epidemiology in Israel, 1995–2009. A) Annual incidence of salmonellosis in Israel. Laboratory-conirmed cases of Salmonella infections per 100,000 population caused by all Salmonella serotypes (black) and by the 5 leading serotypes in Israel. B) The relative contribution (in percentages) of each serotype to the total annual number of Salmonella serotypes. Salmonella infection incidences were constructed according to the number of human Salmonella isolates submitted to the Government Central Laboratories during January 1, 1995–December 31, 2009 (after excluding repeated isolates from the same patient). Data on the Israeli population were derived from the publications of the Israeli Bureau of Statistics. C) Prevalence of S. enterica serovar Infantis and other leading serotypes in poultry. The proportion of different Salmonella serotypes as percentage from the total Salmonella isolates in poultry was analyzed according to routine surveillance in poultry processing plants conducted by veterinary services in 1998–2009. Salmonella isolates have been received, identiied, and documented in the National Salmonella Reference Center of Israel.