View source for Bacteremia vs contaminated blood cultures

==Background==
*[[Staphylococcus aureus]] and Candida sp. isolated from the blood should never be considered a contaminant<ref name="perez"></ref>

==Suggestive of Contamination<ref name="perez">Antibiotic Therapy for Positive Blood Cultures. Perez-Jorge EV, et al. Antimicrobe. http://www.antimicrobe.org/new/e38rev2.asp</ref>==
*Typical commensal organisms of the skin flora '''in the abscence of an intravenous catheter'''
**Coagulase-negative [[Staphylococcus]] species
**Certain [[Streptococci]]
**[[Gram-Positive]] bacilli (rods)
*Only 1 out of 2 or more blood cultures are positive
**When positive for coagulase-negative [[Staphylococcal Species]]
*[[Antibiotic Susceptibility Pattern]] of one organism is different from the pattern of the other organisms in the same or subsequent set of cultures (as long as the organisms are of the same species)
**For example, if 2 sets of blood cultures are both positive for [[Staphylococcus epidermidis]] but one set is sensitive to a particular antibiotic while the other set is resistant to the same antibiotics, both sets are likely contaminated

==Risk Factors for Bacteremia<ref name="perez"></ref>==
*Advanced age
*Corticosteroids
*Immunosuppressing medications (transplant patients, rheumatologic diseases, etc)
*Chronic liver disease
*Chronic renal failure (especially if on hemodialysis)
*Hematological malignancies
*HIV infection
*Intravenous catheters
*Intravenous drug use
*Loss of skin integrity
*Malnutrition and [[hypoalbuminemia]]
*Neutropenia
*Parenteral nutrition

==Contamination Rates for Specific Organisms<ref name="perez"></ref>==
{| class="wikitable"
|-
! Organism !! False positives
|-
| [[Bacillus]] spp. || >90%
|-
| Coag-negative [[Staphylococcus]] spp. || >90%
|-
| [[Propionibacterium]] spp. || >90%
|-
| [[Corynebacterium]] spp. || >80%
|-
| [[Viridans-Group Streptococci]] || 50%
|-
| [[Clostridium]] spp. || 40%
|-
| [[Staphylococcus aureus]] spp. || 25%
|-
| [[Enterococcus]] spp. || 15%
|}

==See Also==
*[[Microbiology (Main)]]

==References==
<references/>

[[Category:ID]]