2.1 Sample collection and bacterial isolation
The case of a 4-year-old girl with typhoid fever and knee arthritis is reported in this study; she was hospitalized in Nantong, Jiangsu, China. The patient presented with 39.5 oC fever and swelling of the knee joint, detected using Nuclear Magnetic Resonance (NMR). The knee effusion, as well as stool and blood samples, were subjected to bacterial detection. Samples were rinsed in selenile broth medium and incubated at 37oC for 16-24 h. The broth culture was then subculture into MacConkey agar, Blood Agar, and XLT4 Agar. The suspected colonies were subjected to species identification using a VITEK-2® Compact (bioMerieux Inc., France). The study was performed following the ethical guidelines of the 1975 Declaration of Helsinki, and was approved by the Ethics Committee of the Chinese Centers for Disease Control and Prevention (CDC).