Blood Culture

I. Materials Needed

1. Sterile gloves.
2. Prep materials -razor, scrub, Betadine, alcohol.
3. 20 cc syringe.
4. 2-19 gauge needles.
   Blood culture broth - Tryptase soy or brain heart infusion broth with agar for anaerobic cultures.
   SPS (Sodium Polyanethol Sulphate) anticoagulant for aerobic culture (Becton Dickinson & Co., Cockeysville, Maryland, USA), (Septi-Chek, Roche Laboratories, Nutley, NJ, USA).
   If blood culture medium is not readily available, the sample can be transferred in a yellow top tube containing anticoagulant citrate (ACD).

II. Method

1. Restraint of foal.
2. Sterile prep of shaved area over jugular vein.
3. Glove and aspirate 20 cc of blood into syringe with 19 gauge needle from jugular or peripheral vein.
4. Remove needle and replace with a new 19 gauge needle.
5. Wipe top of blood culture bottle with 2% iodine.
6. Inject 5-7 cc into each of two bottles.
7. Repeat in 1 or 2 hours up to 3-4 collections if clinical signs allow, before antimicrobial therapy is initiated.
8. If already on antibiotics, take cultures prior to the next scheduled administration of antimicrobials.

III. Interpretation [1-4]

1. Growth in both bottles is significant.
2. Negative blood cultures do not rule out septicemia. Over 50% of foals with E. coli septicemia have negative blood cultures [1]
3. Organisms found most commonly are E. coli, Actinobacillus spp, Klebsiella pneumoniae, Pseudomonas sp., Citrobacter spp., Enterobacter spp., Salmonella and gram-positive organisms such as Streptococcus, Staphylococcus, Enterococcus.