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HelpTest ID ACANT Acanthamoeba/Naegleria species, Corneal Scraping or Spinal Fluid
Useful For
Diagnosis of Acanthamoeba species and Naegleria fowleri, in central nervous system or ocular specimens
Method Name
Direct Wet Prep/Culture
Reporting Name
Acanthamoeba/Naegleria, Corneal/CSFSpecimen Type
VariesForms: If not ordering electronically, complete, print, and send a Microbiology Test Request Form (T244) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf).
Specimen source is required.
Submit only 1 of the following specimens:
Specimen Type: Central nervous system tissue
Container/Tube: Sterile container with 1 mL of saline or minimal essential medium
Specimen Volume: Entire collection
Specimen Stability Information: Ambient
Specimen Type: Contact lens, corneal scraping, corneal tissue
Container/Tube: Sterile container with 1 mL of saline or minimal essential medium
Specimen Volume: Entire collection
Additional Information: The preferred specimen for Acanthamoeba culture from an ocular source is corneal scraping or biopsy. Swab is suboptimal and may result in a falsely negative result. Supplementary slides may be submitted in addition to the scraping or biopsy, but slides alone will not be accepted for testing.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Type: Contact lens solution
Container/Tube: Sterile container
Specimen Volume: 2 mL
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Type: Spinal fluid
Container/Tube: Sterile vial
Specimen Volume: 1 mL
Specimen Stability Information: Ambient
Specimen Minimum Volume
Contact Lens Solution: 1 mL/Spinal Fluid: 0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Varies | 7 days |
Clinical Information
The free-living amebae are ubiquitous in the environment, and may be found in soil and fresh water sources. Naegleria fowleri may enter the central nervous system (CNS) during exposure to infected water and cause a fulminant meningitis in previously healthy individuals. In contrast, Acanthamoeba species and Balamuthis mandrillaris cause chronic granulomatous encephalitis in immunocompromised (and, rarely, immunocompetent) adults, and typically disseminate to the CNS from a primary lung or skin source.
Acanthamoeba species can also cause a painful keratitis when organisms are introduced into the eye. This typically occurs during contact lens use when the lenses or storage or cleaning solutions are contaminated. Amebae can also enter the cornea with abrasion or trauma. Amebic keratitis can cause blindness if untreated. Most cases respond to treatment once a diagnosis is made, but some cases prove to be resistant to therapy with no antimicrobials uniformly active against the organisms.
Reference Values
EYE
Negative for Acanthamoeba species
CENTRAL NERVOUS SYSTEM
Negative for Acanthamoeba/Naegleria species
Cautions
The preferred specimens for Acanthamoeba ocular culture are corneal scrapings or biopsy. Swabs are suboptimal and may result in a falsely negative result. Submission of slides without material for culture is not acceptable.
Wooden-handled swabs are unacceptable for culture since the wood may contain preservatives or other chemicals inhibitory to Acanthamoeba or Naegleria growth.
Transport media that contains antibiotics is not acceptable for this testing (M4 or M5 media or any other viral transport media). Thioglycollate broth is also unacceptable.
Day(s) Performed
Monday through Sunday; Continuously
Report Available
9 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test uses a standard method. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
87081