In the early phases of typhoid fever, Salmonella bacteria can be successfully isolated from________________?
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Answer: C. Blood
Explanation
During the first week of typhoid fever, Salmonella bacteria circulate widely in the bloodstream. Blood culture offers the highest diagnostic sensitivity because bacteremia peaks early in the clinical course. Stool and urine cultures typically become positive later in the infection as the bacteria reach the intestines. Salmonella Typhi is ingested through contaminated food or water, invading intestinal lymphoid tissues. Bacteria spread via the lymphatic system into the bloodstream, establishing systemic infection throughout the body. Diagnostic laboratory testing strategies must align with the timing of bacterial dissemination during the illness.
Early diagnosis using blood cultures allows physicians to initiate appropriate antibiotic therapy promptly. Typhoid fever remains a significant global health challenge in regions with limited sanitation infrastructure. Vaccination programs provide preventive protection for travelers visiting endemic areas worldwide. Fecal cultures have lower sensitivity during the first week and become positive later as bacteria shed from bile. Urine cultures are less effective early on and are typically utilized in later stages of typhoid illness. Not all choices are correct because blood culture is specifically the most sensitive test during early phases.
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