Indications for taking blood cultures and appropriate site selection?

Answer 1

I. INDICATIONSRoutine blood cultures should be performed on any patient in whom there is a suspicion of bacteremia or candidemia.Isolator blood cultures should be performed on any patient suspected of having one of the following:1. Subacute or chronic endocarditis with multiple negative BACTEC system cultures. It is appropriate to use the BACTEC system for the initial workup of endocarditis of any suspected etiology. Isolators should be used after multiple BACTEC cultures are obtained and fail to reveal an etiologic agent (including HACEK).2. Suspected deep fungal infection, such as histoplasmosis, blastomycosis, and coccidioidomycosis. Ordinarily, cultures of other sites, such as tissue biopsy, and in some cases serological tests, are more helpful than blood culture.3. Suspected mycobacteremia, particularly in HIV patients with CD4 counts <50.4. Suspected disseminated gonococcal infection.5. Suspected bartonellosis.6. Suspected candidemia or disseminated cryptococcosis in patients for whom routine cultures have not detected Candida species or Cryptococcus neoformans, respectively.7. Suspected Malassezia furfurinfection, an agent of catheter-associated infection in patients receiving intravenous lipid.The indication for use of isolators should be given to the microbiology resident (pager #980-9869), who must approve the test.The following is not an indication for blood cultures of either type:Surveillance for infection before the clinical suspicion of infection exists.

Answer 2

Blood cultures are indicated in suspected systemic infections, such as sepsis or endocarditis, where bloodstream infection is likely. Appropriate site selection includes clean venipuncture from peripheral veins, using sterile technique, typically drawing from different sites to increase diagnostic yield. Additionally, blood cultures should be taken prior to starting antibiotics if possible to improve sensitivity of detection.