Invasive infection with multidrug-resistant Salmonella enterica serotype typhimurium definitive type 104 among HIV-infected adults.

ABSTRACT

BACKGROUND: Multidrug-resistant Salmonella enterica serotype Typhimurium definitive type 104 (MRDT104), with resistance to at least ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (R-type ACSSuT), was first detected in the United States in 1985, and the prevalence increased to account for nearly 7% of Salmonella infections in 1998. METHODS: A retrospective study of S. Typhimurium infections in an urban health care system assessed whether infection with an antibiotic-resistant strain--and specifically MRDT104--was associated with invasive disease or HIV infection. Sixty cases of S. Typhimurium infection were identified. RESULTS: Of the 50 isolates available for analysis, 30 (60%) were MRDT104. Pathogens were isolated from blood in 25 (83%) of 30 patients infected with MRDT104, compared with 10 (50%) of 20 patients who were infected with non-MRDT104 strains (P = .01). Among isolates obtained from 32 HIV-infected patients, 19 (95%) of 20 MRDT104 isolates were from blood specimens, compared with 8 (66%) of 12 non-MRDT104 isolates (P = .05). CONCLUSIONS: MRDT104 accounted for the majority of S. Typhimurium infections in this patient population, and MRDT104 infections were more invasive than non-MRDT104 infections, particularly in HIV-infected persons.