The "C-swab" test: a technique for identifying bacteria in sinus tracts or tunneled wounds utilizing a cotton swab and bacterial fluorescence imaging.

Background: Complex surgical wounds and nonhealing wounds can develop intricate anatomical variations such as tunnels or sinusoids, making it difficult to assess deep bacterial status. This can lead to false-negative results.

Objective: To propose an alternative bedside diagnostic method using proprietary fluorescence (FL) imaging to visualize high bacterial loads on a sterile cotton applicator probe.

Case Report: In 2 cases of challenging surgical wounds, a sterile cotton applicator was used to collect material from deep within complex, tunneled, or sinusoidal wounds. The applicator was immediately imaged at the bedside for FL signals, and prompt therapeutic action was taken in response to moderate to heavy bacterial detection of multiple species, including Pseudomonas. This newly developed C-Swab test successfully provided point-of-care information on live bacterial presence (or absence) from deep inside wounds, independent of the superficial skin assessment. In those cases, FL scans for superficial bacteria on the skin sometimes appeared negative, while the C-Swab test revealed infection triggering bacteria at deeper levels. This test can be used to evaluate treatment efficacy at subsequent visits (eg, post antibiotics) without major tissue disruption (eg, having to enlarge a wound for inspection).

Conclusion: The addition of the C-Swab test to workflows yields clinically significant information for diagnosis and proactive bacterial management.