ANAEROBIC CULTURES
An anaerobic bacteria culture is a method used to grow anaerobes from a clinical specimen. Obligate anaerobes are bacteria that can live only in the absence of oxygen. Obligate anaerobes are destroyed when exposed to the atmosphere for as briefly as 10 minutes. Some anaerobes are tolerant to small amounts of oxygen. Facultative anaerobes are those organisms that will grow with or without oxygen. The methods of obtaining specimens for anaerobic culture and the culturing procedure are performed to ensure that the organisms are protected from oxygen.
Anaerobic cultures should be considered when you have the following symptoms:
• Foul odor from drainage
• Infection located close to a mucosal surface
• Necrotic tissue, gangrene, pseudomembrane formation
• Gas in discharges and tissues
• Endocarditis with negative routine blood cultures
• Infection related to malignancy or other process producing tissue destruction
• Infection related to the use of aminoglycosides
• Septic thrombophlebitis
• Bacteremic picture with jaundice
• Infections of human or other bites
• Presence of sulfur granules in discharges
• Clinical features of gas gangrene
• Clinical setting suggestive for anaerobic infection (septic abortion, infection after gastrointestinal surgery, genitourinary surgery
For anaerobic specimens, tissue and /or body fluids ( in syringe without needle attached ) are the ideal specimen of choice. These samples should be received in Micro lab within 2 hours of collection. Specimens physicians collect using needle aspiration should be transferred to a sterile tube or anaerobic transport vial prior to transport of the specimen to the laboratory. If the amount is small, a small amount of non-bacteriostatic 0.85% NaCl or broth may be drawn into the syringe prior to removal of the needle. A protective device should be used while removing the needle to avoid injury and should cap the syringe with a sterile cap prior to transporting it to the lab.
The site must be decontaminated before collecting the specimen. Using sterile technique cleanse as follows to avoid contamination with normal flora.
1. Clean the site with 70% alcohol
2. Place iodophor on the site and let it remain for 1 to 2 minutes. Be sure not to touch the site after you decontaminate. Use an alternative to iodophor if the patient is allergic.
3. After obtaining the specimen remove the iodophor with 70% alcohol.
Please Note:
Anaerobic cultures will not be done on body sites that have anaerobes as normal flora such as (stool, skin, vaginal/cervix, mouth, throat, sputum, etc.)
Use transport gel for fluids and tissue specimens. Be sure to decontaminate the gel stopper with alcohol before injecting the specimen.
Do not submit syringes with needles attached.
Submit swabs only when suitable aspirate fluids are not obtainable. Blue tipped BD swabs with gel are available through client services
Store swabs and transport vials at room temperature. DO NOT REFRIGERATE.
