(CR-003) The “C-swab test” for imaging confirmation of bacterial loads in cavernous, sinus, tunneling wounds

Katherine McLeod, RN – Madigan Army Medical Center; Rowena Stefan, RN – Madigan Army Medical Center

Introduction: We are frequently faced with cavernous, tunneling, and/or sinus wounds with small openings and deep extension(s), most commonly pressure ulcers and surgical sites. To determine the bacterial status of these wounds, probes are inserted into the wound and are then sent for a delayed microbiology result. Point-of-care fluorescence (FL) imaging* enables point-of-care mapping of high bacterial loads in regions in and around the wound, and at or near its surface. We propose a new method for immediate visualization of subsurface bacterial presence via FL-scanning of the cotton swab probe, the “C-swab” test.

Methods: We present clinical cases where a cotton swab (Q-tip) was used to collect material from deep inside tunneled, sinusoid, and cavernous wounds. During these clinical encounters, the C-swab was directly imaged at the bedside for FL signals (red for most bacteria, cyan for Pseudomonas) that would indicate live bacterial loads in the moderate to heavy growth range. This prompted immediate therapeutic action, as described.

Results: : The C-swab method was highly successful in providing point-of-care information on live bacterial presence (or absence) from deep inside wounds. We frequently encountered cases where the wound surface appeared innocuous on clinical examination, but infection was brewing underneath. In those cases, FL scans for bacteria at the surface and immediately sub-surface sometimes appeared negative, while the C-swab test revealed high bacterial loads at deeper levels. We were also able to use this test to evaluate treatment efficacy at subsequent visits (e.g., post antibiotics) without major tissue disruption (e.g., having to enlarge a wound for inspection).

Discussion: