Frequently Asked Questions (FAQ)

How does the MolecuLight i:X work?

In a darkened room, or using a DarkDrape™, the MolecuLight i:X shines a safe violet excitation light (405 nm) on a wound. This causes wound components (skin, slough, blood, bacteria, etc.) to fluoresce (or emit light) in different colours1–4.The i:X device displays and captures images of the most informative of these fluorescent colours. Green fluorescence from skin components (i.e. collagen and fibrin) provides anatomical context. Red and cyan fluorescence are associated with regions of bacterial at loads of >104 CFU/g1–3, which is typically moderate-to heavy growth1–3, as demonstrated in multiple clinical studies. Bacterial loads of less than 104 CFU/g, such as the loads of commensal bacteria on healthy skin, are not detected by the MolecuLight i:X1,4.

In addition to bacterial detection, the i:X also performs digital wound area measurement to document and longitudinally monitor the progress of wounds.

Which types of bacteria can be detected?

Pre-clinical and clinical studies have shown that the MolecuLight i:X can detect red fluorescence from Gram positive, Gram negative, aerobic and anaerobic bacterial species1,5.

Pre-clinical research has demonstrated the following species can produce red fluorescence detectable by the MolecuLight i:X in vitro5 (see list below). However, there are many bacterial species not tested here that may also produce red fluorescence6.

Gram negative aerobic species

  • Pseudomonas aeruginosa
  • Escherichia coli
  • Proteus mirabilis
  • Proteus vulgaris
  • Enterobacter cloacae
  • Serratia marcescens
  • Acinetobacter baumannii
  • Klebsiella pneumoniae
  • Klebsiella oxytoca
  • Morganella morganii
  • Stenotrophomonas maltophilia
  • Citrobacter koseri
  • Citrobacter freundii
  • Aeromonas hydrophilia
  • Alcaligenes faecalis
  • Pseudomonas putida

Gram positive aerobic species

  • Staphylococcus aureus
  • Staphylococcus epidermis
  • Staphlyoccus lugdunensis
  • Staphylococcus capitis
  • Corynebacterium striatum
  • Bacillus cereus
  • Listeria monocytogenes

Anaerobic species

  • Bacteroides fragilis
  • Clostridium perfringens
  • Peptostreptococcus anaerobius
  • Propionibacterium acnes
  • Veillonella parvula

What are the clinical benefits of using the MolecuLight i:X?

The MolecuLight i:X can be used at the point-of-care to help wound care practitioners optimize all wound protocols including improved accuracy of sampling7,8, more effective wound cleaning and debridement9–11, as well as helping with dressing and antimicrobial selection4,12. Not only can the i:X help optimize these protocols, it also assists in tracking the effectiveness of treatment plan decreasing bacterial load and wound size9,13. This allows the practitioner to modify the treatment plan if the patient is not responding to the current treatment plan9,13.

Visit our clinical evidence section to learn more about the many clinical benefits of the MolecuLight i:X.

How easy is the MolecuLight i:X to use?

The MolecuLight i:X device is straight-forward to learn and operate. The device’s user interface is designed to be intuitive and easy to use, without requiring a technical background. The device is hand-held and does not require any contrast agents.

MolecuLight provides comprehensive on-site training for all staff and there is a library of online e-learning modules, online assessments, and videos to assist all wound care practitioners with image interpretation.

Why does fluorescence imaging (with the i:X device) need to be performed in the dark?

In order to detect bacteria, fluorescence imaging using the MolecuLight i:X requires a dark room. Darkness is required so that fluorescence signals emitted from the bacteria (and other biological components) in a wound are clearly visualized by the device. In order to ensure a room is sufficiently dark, the i:X has an ambient light sensor to inform the user if the room is dark enough.

If a clinical room can’t be darkened (e.g. an open ward or a treatment room with large windows), a DarkDrape® is available as a disposable, portable dark environment to provide the required darkness for successful point-of-care fluorescence imaging.

Insufficient darkness may lead to images that are not able to be accurately interpreted.

What does it mean that the device shows ‘real-time’ data?

When the “fluorescence mode” (FL-mode) is activated in a dark environment, and an image or video is taken, the fluorescence signatures that indicate bacteria show up immediately on the i:X screen – literally in real-time. No data processing or contrast agents are required. Bacterial detection using fluorescence imaging is instantaneous as long as fluorescence mode is on and the room is dark. As such, the wound care practitioner can move the device around the patient’s wounds to detect the presence and location of potentially clinically significant bacteria. The device, when in fluorescence mode, can also be used to guide (in real-time) cleaning and debridement at point of care9–11.

Is the violet light of the i:X device safe?

Yes. The i:X device illuminates with violet light, which is safe, and not with ultraviolet (UV) light. The i:X device is classified in Risk Group 1 and the laser is Class 1. This means there is not sufficient energy produced by the device to damage skin or eyes in normal use. No safety eye wear is required. However, it is advised to not point the device towards the eyes.

Can I miss the fluorescence signal if there is blood in the wound?

Blood does not fluoresce. It preferentially absorbs the excitation light thereby reducing the likelihood of (bacteria/tissue) fluorescence being generated. Bacteria covered by surface blood may be missed during fluorescence imaging, but this is rare as users should remove blood during wound assessment (when possible). It is recommended that fluorescence imaging be performed after (surface) blood has been removed from the wound bed and periwound areas.

How deep can the i:X device see bacteria beneath the skin?

The MolecuLight i:X can detect bacteria at and below the wound surface (typically to 0.8 mm deep). When a wound is cleaned and debrided using fluorescence image guidance, the clinician may discover bacteria in deeper parts of the wound. Additional confounding factors such as blood, melanin and hyperkeratotic tissue may reduce the detection depth.

Can images be transferred off the i:X device?

Yes. Images, measurements and videos can be transferred from the i:X device to any computer or network using the i:X Connecting Cable or via local Wi-Fi.

Does anything other than bacteria fluoresce?

Yes, the MolecuLight i:X sees all fluorescence. Non-biological sources such as bed sheets, tattoo inks and fluorescent dyes can also fluorescence and may be detected by the MolecuLight i:X. It is always important to compare fluorescence images to standard images for the most accurate interpretation. See this image interpretation publication or take our on-line image interpretation module to learn more.

 

If you have additional questions, please contact us.

 

References

  1. Rennie, M. Y. et al. Understanding Real-Time Fluorescence Signals from Bacteria and Wound Tissues Observed with the MolecuLight i:X(TM). Diagnostics (Basel, Switzerland) 9, (2019).
  2. Rennie, M. Y., Lindvere-Teene, L., Tapang, K. & Linden, R. Point-of-care fluorescence imaging predicts the presence of pathogenic bacteria in wounds: a clinical study. J. Wound Care 26, 452–460 (2017).
  3. Hurley, C. M., McClusky, P., Sugrue, R. M., Clover, J. A. & Kelly, J. E. Efficacy of a bacterial fluorescence imaging device in an outpatient wound care clinic: a pilot study. J. Wound Care 28, 438–443 (2019).
  4. Serena, T. E., Harrell, K., Serena, L. & Yaakov, R. A. Real-time bacterial fluorescence imaging accurately identifies wounds with moderate-to-heavy bacterial burden. J. Wound Care 28, 346–357 (2019).
  5. Jones, L. M. et al. In Vivo and In Vitro Detection of Porphyrin-Producing Wound Pathogens, Planktonic and in Biofilm , with Real-Time Bacterial Fluorescence Imaging. Present. Wounds Canada (2019).
  6. Cavallaro, G., Decaria, L. & Rosato, A. Genome-based analysis of heme biosynthesis and uptake in prokaryotic systems. J. Proteome Res. 7, 4946–4954 (2008).
  7. Farhan, N. & Jeffery, S. Utility of MolecuLight i:X for Managing Bacterial Burden in Pediatric Burns. J. Burn Care Res. (2019). doi:10.1093/jbcr/irz167
  8. Ottolino-Perry, K. et al. Improved detection of clinically relevant wound bacteria using autofluorescence image-guided sampling in diabetic foot ulcers. Int. Wound J. 14, 833–841 (2017).
  9. Raizman, R. et al. Use of a bacterial fluorescence imaging device: wound measurement, bacterial detection and targeted debridement. J. Wound Care 28, 824–834 (2019).
  10. Hill, R., Rennie, M. Y. & Douglas, J. Using Bacterial Fluorescence Imaging and Antimicrobial Stewardship to Guide Wound Management Practices: A Case Series. Ostomy. Wound. Manage. 64, 18–28 (2018).
  11. Hill, R. How effective is your wound cleanser ? An evaluation using bacterial fluorescence imaging. Present. SAWC Spring (2019).
  12. Serena, T. et al. Bacterial fluorescence image guidance of antimicrobial decision making and stewardship. Present. EWMA (2019).
  13. DaCosta, R. S. et al. Point-of-care autofluorescence imaging for real-time sampling and treatment guidance of bioburden in chronic wounds: first-in-human results. PLoS One 10, e0116623 (2015).