Demonstration of persistence of Salmonella typhimurium in an AIDS patient by molecular methods.

We document microbiological persistence of the same Salmonella typhimurium strain in an AIDS patient during 7 months of clinical observation despite prolonged quinolone therapy. Persistence was demonstrated by phage types that closely resembled one another, similar antibiotic resistance patterns, conserved restriction fragment length polymorphism of chromosomal DNA digested with different DNA restriction enzymes, identical ribotypes, and IS200 types in four characterized sequential isolates of S. typhimurium.