University of Iowa
Diagnostic Laboratories
(UIDL) Test Directory

319-384-7212 (local)
1-866-844-2522 (toll free)


Bacterial Culture
Order Form: Laboratory Requisition
Testing
Schedule:
0700-2200, 7 days a week, including holidays.
Comments:
Deliver all specimens to the laboratory as soon as possible after
collection.  Gram stains are automatically performed on fluids and 
exudates other than blood and urine.  Do not send sterile body fluids 
in plastic red top tubes.  These tubes contain a clot activator which 
may affect testing.  Therefore, tests may be unreliable.

Label transport tube with two patient identifiers, date and time of 
collection.

Transport at room temperature unless otherwise specified.
A. Abscess - Tissue or aspirates are always superior to swab specimens.
   Remove surface exudate by wiping with sterile saline or 70% alcohol.
   Aspirate with needle and syringe.  Cleanse rubber stopper of
   anaerobic transport device with alcohol; push needle through septum
   and inject all abscess material on top of agar.  If a swab must be
   used, pass the swab deep into the base of the lesion to firmly
   sample the fresh border.  Transport time is less than or equal to
   2 hours.
B. Anaerobic cultures - Tissue or aspirates are preferred rather than
   swabs.  Fluid collections should be aspirated through disinfected
   tissue or skin.  For superficial ulcers, collect material from below
   the surface (after surface debridement or use a needle and syringe).
   Submit specimens using anaerobic transport media: BBL Port-A-Cul
   anaerobic collection jar for tissue or ACT II tube system for fluid
   and swab specimens. A sterile screw-cap container may be used for
   tissue if transported to the microbiology lab immediately (add
   drops of sterile saline to keep small pieces of tissue moist).
   Deliver all specimens to the laboratory immediately after
   collection.
C. Blood
   a. Adult - Cleanse skin with ChloraPrep one-step 1.5 ml Frepp
      Applicator:
      1) Holding the applicator sponge downward, pinch wings on
         applicator to break ampule and release the antiseptic.
      2) Use a side-to-side motion to scrub the site with the friction
         pad for a full 30 seconds; allow site to dry completely (at
         least 30 seconds before venipuncture.  Do not touch site after
         prep.
      3) Remove overcaps from bottles (1 aerobic and 1 anaerobic) and
         cleanse each rubber septum with separate 70% alcohol swabs.
         Allow septum to dry for 1 min before inoculating.
      4) Draw 20 ml of blood and inoculate each bottle with 10 ml of
         blood.  Do not vent or overfill bottles.  Adding low (<8 ml)
         or high (>10 ml) volumes may adversely affect the recovery of
         organisms. Transport time <2 h.
      5) For adults with a suspected bloodstream infection (BSI),
         collect two initial sets of blood cultures sequentially from
         separate phlebotomy procedures followed by a third and a
         fourth set at 4-6 hour intervals (will detect >99% of BSIs).
         Three sets of blood cultures collected within a 24 hour
         period will detect 96.9 - 98.3% of BSIs. A single set of
         blood cultures to detect BSIs in adults is inadequate (only
         73% sensitivity); two sets of blood cultures will allow
         detection of 87.7-89.7% of BSI episodes. (J Clin Microbiol
         2007; 45:3546).
      6) If patient is allergic to chlorhexidine, prep site with a
         povidone iodine swab stick (907172) applied in concentric
         circles (start at center).  Allow to dry at least 1 min
         before venipuncture.  If patient is allergic to iodine,
         cleanse site with 70% alcohol for 60 sec.
   b. Pediatric - Prepare skin and bottles as for adult.  Collect as
      much blood as possible up to 10 ml per bottle.
D. Bone marrow aspirate - Prepare puncture site as for surgical
   incision.  Inoculate blood culture bottle or lysis centrifugation
   tube.  Transport time is less than 2 hours.  Routine bacterial
   culture of bone marrow is rarely useful.
E. Burn - Clean and debride burn.  Place tissue in sterile screw-cap
   container.  Transfer aspirates to a sterile container. These are
   processed for aerobic culture only.  Quantitative culture may or
   may not be valuable.  A 3 to 4 mm punch biopsy specimen is optimum
   when quantitative cultures are ordered. Cultures of surface samples
   can be misleading.
F. Catheter Tips - Only intravascular catheter tips from pediatric
   patients and peritoneal dialysis catheters are routinely accepted
   for culture.  Send 5 cm of distal tip in sterile screw-cap
   container. Transport time is less than 15 min.  Foley catheters are
   not accepted for culture since growth represents distal urethral
   flora.
G. Cerebrospinal Fluid (CSF) - Aseptically collect CSF from a lumbar
   puncture into sterile tubes.  Send second tube (greater than or
   equal to 3 ml) to the Microbiology Laboratory. Transport time is
   less than or equal to 15 min.  Cerebrospinal fluid for bacterial
   culture should never be refrigerated.
H. Decubitus ulcer - A swab is not the specimen of choice.  Cleanse
   surface with sterile saline.  Submit tissue or aspirate
   inflammatory material from the base of the ulcer in a sterile tube
   or anaerobic system. Transport time is less than or equal to
   2 hours.
I. Ear
   a. Inner ear - Tympanocentesis should be reserved for complicated,
      recurrent, or chronic persistent otitis media. For intact
      eardrum, clean ear canal with soap solution and collect fluid
      via syringe aspiration.  Submit in sterile container.  For
      ruptured eardrum, collect fluid on flexible shaft swab via an
      auditory speculum.  Transport time is less than 2 hours.
   b. Outer ear - Use moistened swab to remove any debris or crust
      from ear canal.  Obtain sample by firmly rotating swab in outer
      canal.  For otitis externa, vigorous swabbing is required -
      surface swabbing may miss streptococcal cellulitis.
J. Eye
   a. Conjunctiva - Sample each eye with separate swabs (premoistened
      with sterile saline) by rolling over conjunctiva.  When only one
      eye is infected, sampling both can help distinguish indigenous
      microflora from true pathogens.
   b. Corneal scrapings - Collected by ophthalmologist.  Using sterile
      spatula, scrape ulcers and lesions; inoculate scraping directly
      onto media (BHI with 10% sheep blood, chocolate, and inhibitory
      mold agar).  Prepare 2 smears by rubbing material onto 1-2 cm
      area of slide.  Transport time is less than or equal to 15 min.
   c. Vitreous fluid - Prepare eye for needle aspiration of fluid.
      Transfer fluid to sterile tube.  Transport time is less than or
      equal to 15 min.
K. Feces - see stool.
L. Fistula - see abscess.
M. Fluids - see sterile body fluids.
N. Genital - Cultures for Neisseria gonorrhoeae should be collected
   with a sterile swab and inoculated directly to a Jembec plate
   (obtain from laboratory; place white tablet in hole of Jembec plate
   to provide CO2 enriched atmosphere, close top of the plate tightly
   and place in ziploc bag provided, keep at room temperature,
   deliver to lab as soon as possible).  If a Jembec plate is
   unavailable, an aerobic culturette swab may be used if transported
   to laboratory immediately.
   a. Endocervical - Remove cervical mucus with swab and discard.
      Insert a second swab into endocervical canal and rotate against
      walls.  Allow time for organisms to absorb onto the swab surface.
   b. Urethral - Collect urethral specimens at least 1 hour after
      patient has urinated.  Insert small swab 2-4 cm into urethral
      lumen, rotate, leave for 2 sec to facilitate absorption.
O. Pilonidal cyst - see abscess.
P. Respiratory, lower - Transport time is less than or equal to
   2 hours.
   a. Bronchoalveolar lavage or brush, endotracheal aspirate - Collect
      fluid in a sputum trap; place brush in sterile container with
      1 ml saline.
   b. Sputum, expectorated - Patient should rinse mouth and gargle
      with water prior to collection; instruct patient to cough
      deeply.  Collect specimens in sterile transport containers.
   c. Sputum, induced - Have patient brush gums and teeth, then rinse
      mouth thoroughly with water.  Using a nebulizer, have the
      patient inhale 20-30 ml of 3 to 10% sterile saline.  Collect
      sputum in sterile container.
Q. Respiratory, upper  - Transport time is less than or equal to
   2 hours.
   a. Oral - remove oral secretions and debris from surface of lesion
      with a swab.  Use a second swab to vigorously sample lesion,
      avoiding normal tissue.  Superficial swab specimens should not be
      submitted. Tissue or needle aspirates are preferred.
   b. Nasal swabs (R/O MRSA) - Insert a sterile swab into the nose
      until resistance is met at the level of the turbinates
      (approximately 2-3 cm into the nose).  Rotate the swab against
      the nasal mucosa.  Repeat the process on the other side.
   c. Sinus aspirates - Aspirate with needle and syringe.  Cleanse
      rubber stopper of anaerobic transport device with alcohol; push
      needle through septum and inject specimen on top of agar.
   d. Throat - Routine throat cultures will be processed only for
      growth of beta-hemolytic Streptococcus species.  Contact
      Microbiology Lab (356-2591) to arrange for provision of special
      media if culture for other organisms (Corynebacterium
      diphtheria, Neisseria gonorrhoeae) is desired.  Do not obtain
      throat samples if epiglottis is inflamed, as sampling may cause
      serious respiratory obstruction.  Sample the posterior pharynx,
      tonsils, and inflamed areas with a sterile swab.
      Refer to: Hygienic Laboratory website for Specimen Collection
      and Shipping Instructions.
R. Sterile body fluids (other than CSF) - Disinfect overlying skin with
   iodine or chlorhexidine preparation.  Obtain specimen with needle
   and syringe.  Transfer fluid to anaerobic transport system
   (cleanse rubber stopper with alcohol; push needle through septum and
   inject fluid on top of agar), sterile screw-cap container, or
   aerobic blood culture bottle. Amniotic and culdocentesis fluids
   should always be transported in an anaerobic system. Submit as much
   fluid as possible.  NEVER submit a swab dipped in fluid.  If blood
   culture bottle is inoculated, submit separate aliquot in sterile
   container for preparation of cytocentrifuged Gram stain.  Transport
   time is less than or equal to 15 min.
S. Stool - Submit 10-20 g in sterile container.  Transport time is
   less than or equal to 1 hrs.  Refrigerate if transport is delayed.
   Routine culture is to rule out Salmonella, Shigella, Campylobacter,
   and E. coli 0157:H7.  Stool cultures are not performed for patients
   who have been hospitalized greater than 3 days without laboratory
   consultation.  Yersinia culture is also available.  Stools for
   c. difficile toxin detection must be transported to the laboratory
   immediately or refrigerated if transport is delayed.
T. Tissue - Submit in anaerobic collection jar or sterile screw-cap
   container; add drops of sterile saline to keep small pieces of
   tissue moist.  Transport time is less than or equal to 15 min.
U. Urine - Collect 1-10 ml of urine in a sterile specimen container
   by catheterization, suprapubic aspiration, or the following
   midstream clean catch method: Patients should be instructed to wash
   hands prior to collection and offered exam gloves.
   a. Female patients should be instructed to sit on toilet with legs
      apart and spread labia with one hand.  First void in toilet and
      then, continuing to void, hold specimen container in "midstream"
      to collect sample.
   b. Male patients should be instructed to retract foreskin if
      uncircumcised.  First void in toilet and then, continuing to
      void, hold specimen container in "midstream" to collect sample.
   Transport urine specimens to the Microbiology Laboratory or
   refrigerate within 30 minutes.  Refrigerated specimens should be
   delivered to the lab as soon as possible, and may be rejected if
   not received within 24 hours of collection.
V. Wound - See abscess.

Cultures are usually completed within 3-5 days.
Instructions:
Contact University of Iowa Diagnostic Laboratories 
1-866-844-2522 (toll free) 
319-384-7213 (Fax)
 
See Additional Information:
Microbiology Specimen Collection and Transport
Normal (Indigenous) Flora of Human Body

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Updated: 07/31/2008