<prompt> Blood culture is done forBrucellosisTyphoidLeptospirosisAll  <response>: Ans. d All. Ref. Anantanarayan, Microbiology, 6thpg.274, 323, 361LEPTOSPIRA Leptospira disappear from blood after 1st week, blood examination is helpful only in early stages. EMJH media can be used to cultivate them. Microscopic agglutination is specific for it, but done in reference labs. Immunofluoroscence has no role.BRUCELLA In Brucellosis, blood culture is most definitive method of diagnosis. Castaneda method is recommended for it. Many a times cultures are unsuccessful and serological tests like agglutination test are performed most often. Rapid methods employed are -- rapid plate agglutination test,- rose Bengal card test and- milk ring test. ELISA differentiates between acute and chronic brucellosis.TYPHOID In typhoid, blood cultures are positive in approximately 90 cases in 1st week of fever, 75 of 2nd week, 60 of 3rd week and 25 thereafter. MacConkey, DC A and Wilson Blair media. Faeces culture is almost as valuable as blood culture, as viruses shed during the disease and in convalescence, but they are also positive in carrier state is a drawback. But this is particularly valuable in patients on antibiotics, as they are not eliminated from faeces. Widal test is negative in 1st week; titres start rising after 1st week, peaks at 3rd to 4th week and then starts falling. Urine culture can be positive in 2nd and 3rd week, that too only in 25 cases. Bone marrow culture is positive in most of the cases, when even blood cultures are negative.Educational Point:The mnemonic BASU is vague and not advisable to remember, because the fact is:B-Blood cultureve in any week, however 90 ve 1st weekA-Agglutinationve in 3rd, 4th weekS-Stool cultureve in any week, but can also be ve in carriersU-Urine cultureve in 2nd and 3rd week 