Curtailed short-term and long-term survival following infection with non-typhoid Salmonella in Israel

Abstract

Among bacterial foodborne pathogens, non-typhoid Salmonella enterica (NTS) is a leading cause of death worldwide. This study assessed short-term and long-term mortality following NTS infection in Israel, and evaluated the effects of age, sex, source of isolation and different serotypes on mortality. The source of data was a national registry of NTS isolates submitted to the Salmonella Reference Center, Government Central Laboratories, in Jerusalem, Israel, during 1997-2006. Vital status was derived from the registry of the Israeli Ministry of the Interior. The survival of a cohort of 15919 patients infected with the top five NTS serotypes was evaluated by calculating age-standardized mortality ratios (SMRs) and by Cox proportional hazards multivariate regressions at three follow-up time intervals: 30 days, 1 year and end of follow-up. The median follow-up time was 6.44 years (mean, 6.21 years; range, 1 day to 10.80 years). The cumulative crude mortality rates at the three time intervals were 0.68%, 1.86% and 4.40%, respectively, corresponding to increased SMRs of 16.95 (95% CI 13.9-20.46), 4.25 (95% CI 3.78-4.76), and 1.83 (95% CI 1.70-1.97), respectively. Cox regressions revealed that increasing age, extraintestinal source of isolation and NTS serotype had significant effects on mortality within all three follow-up intervals. The risk of mortality was increased for serotypes Infantis and Typhimurium, and decreased for serotypes Virchow and Hadar, as compared with serotype Enteritidis. The study revealed curtailed short-term and long-term survival following NTS infection that persisted for many years following detection by culture. © 2010 The Authors. Journal Compilation © 2010 European Society of Clinical Microbiology and Infectious Diseases.