Culture, Blood

BLOOD CULTURE

Blood culture

Culture
Gram Stain - added when culture positive
Anaerobic Culture - performed when indicated
BCID PCR added when culture positive
 

Blood received in BD BACTEC bottles, use both aerobic and anaerobic bottles to make 1 set.
BD Bactec Plus Aerobic medium bottle
BD Bactec Lytic Anaerobic medium bottle

5-10mls per bottle.

The IV team, ER nurses, selected physicians or designees are responsible for drawing blood cultures.  Most cases of bacteremia are detected by using two sets of separately collected blood cultures. The microbiology laboratory routinely uses the 2 bottle BD BACTEC blood culture system (1 aerobic (blue cap) and 1 anaerobic (purple cap) bottle makes a set. Place one order per set. More than two sets of blood cultures yield little additional information. Conversely, a single blood culture may miss intermittently occurring bacteremia and make it difficult to interpret the clinical significance of certain isolated organisms.
 
When other lab work is needed, blood culture should be done first.  Collect blood before administration of antibiotics when possible.

Appropriate aseptic techniques must be followed for the procurement of blood for culture to reduce the chance of contamination.  Contaminants cost time and money.  Attention should be paid to maintaining sterility of the blood culture bottle tops as well as any needles and syringe openings. If the venipuncture site is to be palpated before needle insertion, (whenever possible, peripheral sites are preferred) sterile gloves must be worn.

The volume of blood is critical because the number of organisms in most cases of bacteremia is low. Since we deal only with adult patients, obtain 20 ml of blood per venipuncture and put 8-10 ml into each bottle of the two-bottle set (aerobic and anaerobic). Do not overfill or underfill the bottles. There are 5 ml markings on the side of the bottle. It can be helpful to pre-mark the line for 10 ml prior to drawing when the bottle is upright.
 

Place labels which do not have the bar code over on vials. bottles. DO NOT cover the bottom of the bottle or the entire barcode. Label vertically. Document label with your initials, date and time collected. Write pertinent information such as central line, peripheral etc. Transport in biohazard bag at room temperature.

Routine Blood culture bottles are used for the isolation of bacteria and yeast only. Yeast grows well in routine blood culture bottles,  If there is suspicion of Mycobacteria, di-morphic or filamentous fungi see specific test information (AFB Culture, Blood or Mycology Culture, Blood), do NOT use routine Blood culture bottles or order Blood Culture test for those organisms. Myco-F Lytic Bottles are used for the isolation of Mycobacteria, di-morphic or filamentous fungi.

Cultures may be reported as possible contaminant with no further workup.  Contact lab or Infectious Disease if needed.

SPECIMEN COLLECTION
It is recommended that the specimen be inoculated into the BD BACTEC bottles at bedside. If appropriate, a Vacutainer™ brand Needle Holder and a Vacutainer brand Blood Collection Set, Vacutainer Safety-Lok™ Blood Collection Set or other tubing “butterfly” set may be used. If using a needle and tubing set (direct draw), carefully observe the direction of blood flow when starting sample collection. The vacuum in the bottle will usually exceed 10 mL, so the user should monitor the volume collected by means of the 5 mL graduation marks on the side of the bottle. It can be helpful to pre-mark the line for 10 ml prior to drawing when the bottle is upright.  Do NOT overfill bottles.  When the desired 8 – 10 mL has been drawn, the flow should be stopped by crimping the tubing and removing the tubing set from the BD BACTEC bottle.  Sample volumes as low as 3 mL can be used, however, recovery will not be as great as with larger volumes.

PROCEDURE
Assemble equipment:
 

a) Butterfly with bottle guide

b) BD Bactec: Aerobic (blue cap) bottle

c) BD Bactec: Anaerobic (purple cap) bottle

d) Chlora-Prep applicator (iodine is NOT recommended)

e) Serile gloves

f) Isopropyl Alcohol preps (one/culture bottle)

g) Tourniquet

h) Labels

i) Flexible bandage

j) 2x2 gauze

k) Transport bag

Inspect the BD Bactec bottles for cracks, contamination, excessive cloudiness, and bulging or indented stoppers.  DO NOT USE if any defect is noted.

Aseptically inject or draw directly 8 – 10 mL of specimen per bottle.

1. Verify physician’s order, including the site and number of cultures requested.
2. Verify patient’s identification (using 2 identifiers).
3. Explain procedure to patient and obtain verbal consent.
4. Position patient for comfort, as condition allows:
        a) Reclining or Semi-Fowler’s is preferred
5. Select primary site and secondary site if requested.
6. Wash hands and don sterile gloves
7. Activate Chlora-prep by squeezing wand, clean area using brisk strokes in TWO different directions. Allow to dry completely. Once cleaned DO NOT re-touch surface with hand/ fingers. 
8. Remove the cap over culture bottles, clean rubber stopper with alcohol prep and allow alcohol prep to dry. Remove alcohol prep
9. Assemble the butterfly to vacutainer.
10. Change into new pair of sterile gloves
11. Access the vein using the butterfly in a single motion. Insert the aerobic bottle and fill with 8-10 ml blood. Remove, then insert the anaerobic bottle and allow bottle to fill with 8-10 ml blood. Remove bottle.
12. Remove butterfly from vein, applying the sterile 2x2 gauze. Rap with flexible bandage over gauze.
13. Use one order for both bottles.  Place labels which do not have the bar code over on bottles. DO NOT cover the bottom of the bottle or the entire bottle barcode. Label vertically. Document label with your initials, date and time collected. Write pertinent information such as central line, peripheral etc.
14. Discard equipment in appropriate receptacle, remove gloves, and wash hands.
15. Repeat procedure if second site is requested.
16. The inoculated BD BACTEC bottle should be transported in a biohazard bag as quickly as possible to the laboratory at room temperature.

  



 

Room temperature: ≤ 15 minutes

1. Room temperature: ≤ 24 hours

Blood not received in BD BACTEC bottles.

Daily

TAT
Gram stain result as soon as bottle signals positive (16-48 hours)
5 days for Negative cultures

Low inoculum could lead to false negatives or longer turnaround time.

No Growth on Culture