Comparison of the clinical and laboratory features of muscle infections caused by Salmonella and those caused by other pathogens

Muscle infections caused by Salmonella constitute an uncommon complication of extraenteric salmonellosis. The aim of this study was to compare the clinical features of Salmonella muscle infections with those reported in several large series of typical, both tropical and non-tropical, pyomyositis, caused mostly by Staphylococcus aureus. A literature survey of Salmonella muscle infections was carried out by using MEDLINE files 1966 through 2000, and cross-references from the selected articles, as well as major reviews of Salmonella infections and of pyomyositis. The survey yielded 32 cases suitable for analysis. The sex distribution, duration of symptom at presentation, degree of fever, involvement of multiple muscle groups, and leukocyte counts were not significantly different between patients with muscle infections caused by Salmonella and typical pyomyositis patients. In contrast, the median age of the patients with Salmonella muscle infections, and the rate of underlying conditions, were significantly higher than those in typical pyomyositis. Psoas muscle was involved more commonly in Salmonella infections than in typical pyomyositis, and the yield of positive blood cultures and, particularly, the mortality rate, were substantially higher in Salmonella muscle infections than in typical pyomyositis. We conclude that patients with Salmonella muscle infections seem to have some different characteristics with respect to typical pyomyositis, such as older age, and higher rates of associated conditions, psoas muscle involvement, bacteremia, and mortality.