Laser-assisted nasal decolonization of Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus

Methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S aureus (MRSA) contribute to 25% of nosocomial infections, increasing complications, health care cost, and growing antibiotic resistance. Nasal decolonization (ND) can reduce the staphylococcal infection rate. A new method of laser therapy (LT) MRSA ND was tested.

This is a prospective, nonrandomized study.

Following institutional review board approvals, 25 patients colonized with MSSA/MRSA were allocated to 4 treatment arms; low-power, dual-wavelength 870-/930-nm laser alone (GR1); low-power, dual-wavelength laser followed by erythromycin (E-mycin) cream (GR2); low-power, dual-wavelength laser followed by peroxide irrigation (GR3); and high-power 940-nm laser alone (GR4). Quantitative cultures were obtained before and after in all arms. Laser therapy was performed via a laser fiber diffuser, delivering 200 to 600 J/cm² to each naris circumferentially. Patient's distribution was 3 in GR1, 14 in GR2, 4 in GR3, and 4 in GR4 (last 10 recruited to GR4).

Nasal decolonization for GR1, GR2, GR3, and GR4 was 1 of 3, 13 of 14, 2 of 4, and 4 of 4, respectively. Because LT + E-mycin cleared all first 3 patients of MRSA and MSSA, all remaining patients were treated with LT + Er with over 90% of patients clearing. No adverse events or discomfort were reported.

First human study using LT and topical E-mycin in ND is presented. Laser therapy can eradicate MRSA and potentially resensitization of bacteria to the antimicrobial effect of erythromycin. Although decolonization was maintained at 4 weeks posttreatment, further studies can determine the LT long-term effect.