Typhoid in 1st week is best diagnosed by
Ans. a (Blood culture). (Ref. Harrison, Medicine, 18th/ Chapter 153. Salmonellosis )# 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, DCA 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.Note: The diagnostic 'gold standard' for diagnosis of typhoid is culture, for salmonella typhi or paratyphi. The mnemonicBASU is very vague and not advisable to remember, because the fact is...B-Blood culturepositive in any week, however 90% positive 1st week.A-Agglutinationpositive in 3rd, 4th week.S-Stool culturepositive in any week, but can also be positive in carriers.U-Urine culturepositive in 2nd and 3rd week.
Blood culture
Antigenic test
Stool culture
Urine culture
Enterobecteriaceae