LifeBridge Health Home Sinai Department of Pathology Pathology Lab Users Guide Microbiology Microbiology 9

Font size LifeBridge Health - Department of Pathology Microbiology back G. Sterile body fluids (excluding CSF, urine, and blood)        Clean the needle puncture site with alcohol, and disinfect it with an iodine solution (1 to 2% tincture of iodine or a 10% solution of povidone-iodine [1% free iodine]) to prevent infection. (If tincture of iodine is used, remove with 70% ethanol after the procedure to avoid burn.) The physician will aseptically perform percutaneous aspiration to obtain plueral, pericardial, peritoneal, or synovial fluids. Expel any air bubbles from the syringe, and immediately inject the specimen into an anaerobic transport system or send the specimen in the syringe. Transport additional fluid or pus in a sterile screw-cap container. Sterile body fluid collection considerations are summarized in Table 9. back H. Subcutaneous tissue and skin specimens        Burn specimens The surfaces of burn wounds will become colonized by the patients microbiota or by environmental organisms.  When the organism load is large, infection of under lying tissue may occur, and bacteremia may ensue.  Cultures of the surface alone are misleading; therefore, biopsies of deeper tissue are often indicated.  Additionally, organisms may not be distributed evenly in the burn wound, so sampling of different areas of the burn is recommended. a) Disinfect the surface of the burn with 70% alcohol and then with an iodine solution (1 to 2 % tincture of iodine or a 10% solution of povidone-iodine [1% free iodine]).  Allow the disinfectant to dry prior to collecting the specimen.  Note: blood cultures should be used to monitor patient status.  If tincture of iodine is used, it must be removed with 70% alcohol after the procedure to prevent burns. b) Collect a punch biopsy sample (3 to 4 mm) for quantitative culture. Superficial wound, bacterial a) Syringe aspiration is preferable to swab collection. b) Disinfect the surface of the wound with 70% alcohol and then with an iodine (see 1a. above). c) Using a 3- to 5 ml syringe with a 22- to 23- gauge needle, a physician will aspirate the deepest portion of the lesion.  If a vesicle is present, collect both fluid and cells from the base of the lesion. d) If the initial aspiration fails to obtain material, inject sterile, nonbacteriostatic 0.85% NaCl subcutaneously. e) Repeat the aspiration attempt. f) If no material is obtained, rinse needle and syringe with broth by drawing the culture medium through the needle into the syringe. Superficial lesion, fungal a) Clean the surface with sterile water. b) Using a scalpel blade, scrape the periphery of the lesion border. Samples from scalp lesions should include hair that is selectively collected for examination.  If there is nail involvement, obtain scrapings of debris or material beneath the nail plate.  Transport in a sterile container or sterile petri dish. Ulcers and nodules a) Clean the area with 70% alcohol and iodine (see 1a above). b) Remove overlying debris. c) Curette the base of the ulcer or nodule. d) If exudate is present from ulcer or nodule, collect it with a syringe or sterile swab. Subcutaneous tissue and skin specimen collection considerations are summarized in Table 10. back I. Deep wounds, aspirates, and tissue specimens   Bite wounds Aspirate pus from the wound, or obtain it at the time of incision, drainage, or debridement of infected wound. (Do not culture fresh bit wounds, as infectious agents will likely not be found.) Bone a) Obtain bone specimen at surgery. b) Submit in sterile container without formalin.  Specimen may be kept moist with sterile 0.85% NaCl. Deep wounds or abscesses a) Disinfect the surface with alcohol/iodine preps (see 1a. above). b) Aspirate the deepest portion of the lesion, avoiding contamination by the wound surface. If collection is done at surgery, a portion of the abscess wall should also be sent for culture. Punch skin biopsies a) Disinfect the skin surface (see 1a above). b) Collect 3- to 4- mm sample with dermal punch. c) Submit for microbiological analysis in sterile container without formalin. Soft tissue aspirate a) Disinfect the surface (see 1a above). b) Aspirate deepest portion of the lesion or sinus tract.  Be careful to avoid contamination by the wound surface. Deep wound, aspirate, and tissue specimen collection considerations are summarized in Table 11.

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