Impact of low-level laser therapy on the dynamics of pressure ulcer-induced changes considering an infectious agent and cathelicidin LL-37 concentration: a preliminary study

Introduction
Low-level laser therapy is used in managing chronic wounds including pressure ulcers. Less is known about its impact on the healing process if an inhibitive agent e.g. bacterial infection takes place. Modulating non-specific immunity processes might eliminate bacteria if laser therapy is applied.

Aim
To investigate the impact of low-level laser therapy on pressure ulcer dynamics considering an infectious agent and cathelicidin LL-37 concentration.

Material and Methods
The study comprised 6 patients with pressure ulcers ranging from stage II to III in Torrance classification and 12 patients without pressure ulcers. Venous blood sample and decubitus wound swab were taken – in study groups A at baseline and after 2 weeks; in control group B once – at a specific point of time. The swabs served for species identification. Drug susceptibility of isolated pathogens and cathelicidin LL-37 in serum concentration were measured.

Results
In study group A, the following bacteria predominantly occurred: S. aureus, E. faecalis, P. mirabilis, P. aeruginosa, while in control group B, excluding one MRSA case, S. hominis, S. epidermidis, D. nishinomiyaensis, A. haemolyticus (physiological flora) were present. HLGR resistance mechanisms were detected when analyzing drug susceptibility panels. Study group A findings demonstrated a statistically significant difference between the levels of cathelicidin LL-37 concentration at baseline and at the end.

Conclusions
There is insufficient information to accurately determine the effect of LLLT on pressure ulcer dynamics considering an infectious agent. These effects may occur if innate immunity processes are modulated so that laser therapy might eliminate bacteria indirectly.