Depending on the stage of the illness, Salmonella typhi can be successfully isolated from______________?
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Answer: D. All of the above
Explanation
Salmonella typhi bacteremia occurs early in the infection cycle, making blood cultures reliable during the first week. As the systemic infection progresses, the bacteria localize in the gallbladder and are shed continuously into feces. Renal excretion later in the disease course allows successful isolation of the pathogen from patient urine samples. Salmonella typhi is the causative agent of typhoid fever, a severe systemic illness acquired through contaminated food. The pathogen invades the mononuclear phagocyte system and disseminates widely throughout internal human organs. Diagnostic protocols require careful selection of clinical specimens based on the exact duration of patient symptoms.
Option A is incorrect because focusing solely on feces misses early diagnoses obtainable through blood cultures. Option B is incorrect because blood cultures become less reliable during later stages of typhoid fever. Option C is incorrect because urine sampling alone is insufficient without considering blood and fecal cultures.
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