Culture, Aerobic - with Susceptibilities

Marshfield Lab Public WebSite

Marshfield Clinic Public WebSite

Test Code: AERS

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Aerobic culture, C and S

Specimen Requirements

Fasting Required	Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
No	Aspirates and exudates	Sterile, leakproof container	ESwab™, or other Amies medium based swab	1-10 mL 1 swab	0.5 mL fluid, or one swab	0.5 mL fluid, or one swab
	Bone Marrow	Sterile, leakproof container or Vacutainer with SPS		1-1.5 mL	0.5 mL	0.5 mL
	Bronchial brush	Submit in 1 mL Sterile saline		1 brush	1 brush	1 brush
	Bronchial lavage (BAL), bronchial wash	Sterile, screw-cap leakproof container (10-100mL)		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Catheter tip (other than Foley)	Sterile, wide-mouth screw-cap leakproof container		1 tip	1 tip	1 tip
	Endotracheal aspirate	Aspiration trap (Leuke trap)		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Fluid (other than blood, urine and feces)	Sterile, leakproof container		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Scrapings	Sterile, leakproof container		1g	1g	1g
	Sputum	Sterile, wide-mouth screw-cap leakproof container		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Tissue, Bone, or Hardware	Sterile, wide-mouth screw-cap leakproof container. For small tissues, add several drops of sterile saline to keep moist.		1-10g 1 pc hardware	0.5 g tissue or bone	0.5 g tissue or bone
	Upper respiratory secretions	Sterile, leakproof container	ESwab, or other Amies medium based swab	1-10 mL 1 swab	0.5 mL fluid, or one swab	0.5 mL fluid, or one swab
	Wound	Sterile, leakproof container	ESwab, or other Amies medium based swab	1-10 g 1 swab	0.5 g tissue, 0.5 mL fluid, or one swab	0.5 g tissue, 0.5 mL fluid, or one swab

Collection Processing Instructions

Specimens should be delivered to the microbiology laboratory as soon as possible. Culture of specimens older than 24 hours may lead to a reduction in recovery of microorganisms. Gram stains will routinely be performed if sufficient specimen is received.

Swabs:
- ESwab: one swab can be collected for Gram stain, aerobic, anaerobic, and fungal cultures.

- Other Amies/Stuart medium swab types: collect one swab for every culture and stain (including Gram) to be ordered.

See eSwab Collection Video for more information

For blood, feces, and urine specimens, use tests specific to those specimen types.

Lower Respiratory Tract Secretions: Early morning specimens are preferred because secretions will have pooled overnight. However, samples may be obtained whenever the patient is productive. Sputum samples will be screened for suitability by Gram stain: samples found to be contaminated with saliva will be rejected.

For more information on Specimen Collection Media/Swab, see Specimen Transport Pictorial.

Acceptable Specimen Types

Bone, Bronchial, Catheter Tip, Fine Needle Aspirate, Fluid, Hardware, Respiratory Secretions, Skin Scraping, Swab, Synovial, and Tissue.

Specimen Stability Information

Specimen Type	Temperature	Time
Swabs (single, dual) in gel or preservative media (Stuart, Amies)	Room temperature	<= 4 hours
	Refrigerate	< 24 hours
ESwab	Room temperature	≤ 48 hours
ESwab	Refrigerate	≤ 48 hours
Tissues, body fluids, aspirates	Refrigerate	> 4 hours
Catheter tips	Room temperature	<= 4 hours
Catheter tips	Refrigerate	> 4 hours
Gastric, biopsy or lavage	Room temperature	<= 4 hours
Gastric, biopsy or lavage	Refrigerate	> 4 hours
Lower respiratory secretions (bronchial, sputum, endotracheal)	Room temperature	<= 4 hours
	Refrigerate	> 4 hours
Bone Marrow	Room temperature	<= 14 hours

Rejection Criteria

Contaminated expectorated sputum specimens per Gram stain screening procedure
Dry swabs
Swab specimens collected in preservative media (Amies/Stuart's) > 24 hours
ESwab specimens > 48 hours
Leaking specimens
Specimens older than 4 days

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Analytical Time	Methodology/Instrumentation
Marshfield	Monday through Sunday	varies with specimen type (average 3-4 days)	Conventional culture, microscopic exam, standard susceptibility testing, manual or automated identification methods, nucleic acid sequence analysis as needed.

Test Information

Gram stains will routinely be performed on all respiratory secretions, tissues, and fluids (other than blood, feces and urine), specimen volume permitting. A Gram stain will be performed on swab-collected specimens if an ADDITIONAL swab is submitted (i.e. one swab for aerobic culture and a second swab for Gram stain).

For Lower Respiratory Tract (LRT) Secretions:
Gram stains are routinely performed on sputum specimens to determine acceptability for culture. The reliability of culture is very dependent upon the method of collection, conditions of transport, and the quality of the specimen. Some organisms will not grow in routine culture, but can be a significant cause of lower respiratory tract disease. False-negative results may be obtained due to contamination of the specimen with normal oropharyngeal flora, or from previous antimicrobial therapy. False-positive results may be obtained when the culture is over-interpreted, or when potentially pathogenic organisms that are colonizers of the upper respiratory tract are recovered.

Antimicrobial Susceptibility Testing (AST) will be performed on significant bacterial isolates with unpredictable patterns if standardized methods are available based upon Clinical Laboratory Standards Institute guidelines. Methods used include disk diffusion, minimum inhibitory concentration (MIC) by broth microdilution, or MIC by Etest®.

A listing of the tested and reported antimicrobial agents can be seen at Antimicrobial Susceptibility Panels. If testing against a specific antimicrobial agent is desired, contact the microbiology laboratory.

The microbiology laboratory uses selective reporting of susceptibility results to promote rational antimicrobial usage. For more information on selective reporting, please contact the microbiology directors.

Standardized AST is not available for all bacterial species, in which case an MIC determined by a non-standardized method and without interpretation may be available upon request. Contact the microbiology laboratory for more information.

The microbiology laboratory publishes an annual cumulative antibiogram for commonly isolated bacteria, available at Cumulative Antibiogram Reports. Printed copies are also available from the microbiology laboratory.

‘ESwab’ is a trademark of Copan Diagnostics.

‘E-test’ is a registered trademark of bioMerieux Inc.

Reference Range Information

Performing Location	Reference Range
All Performing Sites	Sterile sites: No growth Non-sterile/mucosal sites: Mixed Indigenous Flora

Performing Location

Reference Range

All Performing Sites

Sterile sites: No growth

Non-sterile/mucosal sites: Mixed Indigenous Flora

Outreach CPTs

CPT	Quantity	Description	Comments
87070	1	Culture
87205	1	Gram stain	By specimen type
87176		Homogenization, tissue	By specimen type
87077		Aerobic isolate, definitive ID	As needed
87186	1-2+	MIC susceptibility, micro-broth dilution	1-2 per organism, as needed
87184		KB (disk) susceptibility	As needed
87181		MIC susceptibility, Etest® strip gradient	As needed
87147		Serotyping/grouping	As needed
87185		Enzyme detection	As needed
87153		ID by nucleic acid sequencing method	As needed
'ESwab' is a trademark of Copan Diagnostics. 'Etest' is registered by BioMerieux Inc.

Synonyms/Keywords

Aerobic culture, C and S

Ordering Applications

Ordering Application	Description
Cerner	Aerobic Culture with Sensitivity (w/Gram Stain)

If the ordering application you are looking for is not listed, contact your local laboratory for assistance.

Specimen Requirements

Fasting Required	Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
No	Aspirates and exudates	Sterile, leakproof container	ESwab™, or other Amies medium based swab	1-10 mL 1 swab	0.5 mL fluid, or one swab	0.5 mL fluid, or one swab
	Bone Marrow	Sterile, leakproof container or Vacutainer with SPS		1-1.5 mL	0.5 mL	0.5 mL
	Bronchial brush	Submit in 1 mL Sterile saline		1 brush	1 brush	1 brush
	Bronchial lavage (BAL), bronchial wash	Sterile, screw-cap leakproof container (10-100mL)		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Catheter tip (other than Foley)	Sterile, wide-mouth screw-cap leakproof container		1 tip	1 tip	1 tip
	Endotracheal aspirate	Aspiration trap (Leuke trap)		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Fluid (other than blood, urine and feces)	Sterile, leakproof container		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Scrapings	Sterile, leakproof container		1g	1g	1g
	Sputum	Sterile, wide-mouth screw-cap leakproof container		1-10 mL	0.5 mL fluid	0.5 mL fluid
	Tissue, Bone, or Hardware	Sterile, wide-mouth screw-cap leakproof container. For small tissues, add several drops of sterile saline to keep moist.		1-10g 1 pc hardware	0.5 g tissue or bone	0.5 g tissue or bone
	Upper respiratory secretions	Sterile, leakproof container	ESwab, or other Amies medium based swab	1-10 mL 1 swab	0.5 mL fluid, or one swab	0.5 mL fluid, or one swab
	Wound	Sterile, leakproof container	ESwab, or other Amies medium based swab	1-10 g 1 swab	0.5 g tissue, 0.5 mL fluid, or one swab	0.5 g tissue, 0.5 mL fluid, or one swab

Collection Processing