Question

Essential major blood culture criteria for infective endocarditis.

• A. Single positive culture of hacek
• B. Single positive culture of coxiella
• C. Single positive culture of cornybacterium
• D. Both a & b

Answer 1

The Correct Option is A

In the diagnosis of infective endocarditis, one of the essential criteria involves blood culture identification of specific organisms. The HACEK group, which includes Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species, is considered one of the notable culprits for infective endocarditis. Therefore, a single positive blood culture with HACEK organisms can be significant for the diagnosis. Other criteria include the microbiological identification of Coxiella burnetii; however, a single positive blood culture of Coxiella is not sufficient, as serology showing elevated phase I IgG antibody titer is also required for diagnosis. 

Organism	Diagnosis Significance
HACEK Group	Single positive culture is significant
Coxiella burnetii	Requires both culture and elevated antibody titer
Cornybacterium	Usually contaminant, not significant alone

Therefore, the correct option recognizing the essential major blood culture criterion for infective endocarditis is a single positive culture of HACEK, which signifies a clinically significant finding.