Salmonellosis localized infections

Localized infections occur in 5% to 10% of cases with Salmonella bacteremia. Sites for extraintestinal complications of salmonellosis include endocarditis, arteritis, central nervous system, lung, bone, joints, muscle/soft tissue, splenic, and genitourinary. 

Human disease caused by Salmonella generally falls into four categories acute gastroenteritis (enterocolitis), bacteremia, extraintestinal localized infection, and enteric fever (typhoid and paratyphoid fever), and a chronic carrier state. S. typhimurium is the most common cause of salmonellosis. Salmonellosis is a disease primarily of infants, children, and adolescents. 

A variety of other clinically important infections, such as brucellosis, listeriosis, salmonellosis, and various Mycobacterium infections, are of interest as these are often localized in organs rich in MPS cells. Liposome encapsulation has been demonstrated to improve therapeutic indices of several drugs in a number of infectious models. The natural avidity of macrophages for liposomes can also be exploited in the application of the vesicles as carriers of immunomodulators to activate these cells to an microbicidal, antiviral, or tumoricidal state. These studies were recently reviewed by Emmen and Storm (1987), Popescu et al. (1987), and Alving (1988). In addition to the treatment of "old" infectious diseases, the concept of MPS-directed drug delivery is of considerable interest for the therapy AIDS, possibly enabling control of human immunodeficiency virus replication in human macrophages. 

Members of the Salmonella enterica enterica subspecies are the cause of most human salmonellosis and in the USA, most cases are food-borne. S. enterica enterica consists of more than 2500 different O and H cell surface antigen combinations, or serovars (FDA 2012). S. enterica serovar Typhimurium and S. enterica serovar Heidelberg are among the top ten serovars implicated in food-borne Salmonella infections (CDC 2014). Although these are distinct serovars, their genomes are 99% similar (data not shown). Species- and subspecies-level assays are generally adequate for clinical diagnostics. However, localization of the source of a food-borne Salmonella contamination requires serovar or strain-level speeificity. 

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