Classifying extraintestinal non-typhoid Salmonella infections

Non-typhoid Salmonella infection in man has been divided into five clinical groups: gastroenteritis, enteric fever, bacteraemia, chronic carrier state and localized infection. This classification has neither pathogenic nor prognostic significance. We retrospectively reviewed the charts of 183 patients with extraintestinal salmonellosis who presented to our institution during a period of 32 years. Patients were classified into four groups: primary bacteraemia (PB), enteritis-associated bacteraemia (secondary bacteraemia) (SB), digestive focal infection (DI) and non-digestive focal infection (NDI). Sex, age, acquisition, underlying disease and outcome were compared between patients with bacteraemia and diseases with focal infection. The differences found between PB and SB were: community acquisition (66% in PB and 85% in SB, p = 0.06) severe immunosuppression (53% in PB and 15% in SB, p < 0.001) and mortality (37% in PB and 3% in SB, p < 0.001). The differences found between NDI and DI were: age over 60 years (45% in NDI and 18% in DI, p < 0.05), severe immunosuppression (51% in NDI and 12% DI, p < 0.001) and associated bacteraemia (38% in NDI and 6% in DI, p < 0.001). This classification of extraintestinal salmonellosis may have pathogenic and prognostic implications, and could help us to understand the clinical significance of this disease.