The effects of photobiomodulation therapy on Staphylococcus aureus infected surgical wounds in diabetic rats. A microbiological, histopathological, and biomechanical study

ABSTRACT PURPOSE: To evaluate the effects of photobiomodulation therapy (PBMT) at 685 nm on diabetic wound healing in rats suffering from bacterial infection induced by Staphylococcus aureus (S. aureus). METHODS: Thirty streptozotocin-induced diabetic rats were allocated into two groups: control and PBMT. A 4-cm full-thickness linear-incision was made on the dorsal midline and was contaminated with S. aureus. The wounds in the PBMT group were irradiated daily for 5 consecutive days, starting 3 days after the induction and always in the mornings. RESULTS: The result revealed that PBMT resulted in a significant decrease in S. aureus CFU in the PBMT group in comparison to the control group (P<0.05). The length of wounds, in the 2nd and 3rd weeks, in the PBMT group were significantly shorter compared to the control group (P<0.05). PBMT caused a significant increase in the histological parameters in comparison to the control group (P<0.05). Moreover, PBMT significantly increased the breaking strength of the surgical scars produced in the skin of the PBMT group when compared to the control group (P<0.05). CONCLUSION: Photobiomodulation therapy may be useful in the management of wound infection through a significant bacterial growth inhibition and an acceleration of wound healing process.

The effects of low level laser therapy on Staphylococcus aureus infected third-degree burns in diabetic rats

PURPOSE: To characterize the effects of low-level laser (LLL) on third-degree burn wounds which were infected with Staphylococcus aureus (S. aureus) in diabetic rats. METHODS: Thirty streptozotocin-induced diabetic rats were divided into two groups: the control and the LLL groups. Third-degree burns were induced using a heated metal rod, and then, were contaminated with S. aureus. The wounds in the LLL group were irradiated with a LLL (685nm) daily for five consecutive days, starting three days after the induction. The wound area was measured at 3, 5, 8, 14 and 21 days after burning. At the end of trial, the skin samples were harvested. RESULTS: Reduction in wound areas in the LLL and control groups were significantly different only on the 21st day (p<0.05). The mean bacterial numbers in the LLL group were significantly lower (p<0.05) than those in the control group. The number of macrophages, new blood vessels, fibroblast, and elevated collagen deposition in the LLL group significantly increased compared to the control group (p<0.05). The mean breaking strength of scars in the control group was significantly lower (p<0.05) than that of the LLL group. CONCLUSION: The low-level laser improved the healing of S. aureus third-degree burn infections in diabetic rats.

Low level laser therapy (AlGaInP) applied at 5J/cm2 reduces the proliferation of Staphylococcus aureus MRSA in infected wounds and intact skin of rats* / Laser de baixa intensidade (AlGaInP) aplicado com 5J/cm2 reduz a proliferação de Staphilococcus aureus MRSA em feridas infectadas e em pele íntegra de ratos

Laser therapy is a low cost, non-invasive procedure with good healing results. Doubts exist as to whether laser therapy action on microorganisms can justify research aimed at investigating its possible effects on bacteria-infected wounds. To assess the effect of low intensity laser on the rate of bacterial contamination in infected wounds in the skin of rats. An experimental study using 56 male Wistar rats. The animals were randomly divided into eight groups of seven each. Those in the "infected" groups were infected by Staphylococcus aureus MRSA in the dorsal region. Red laser diode (AlGaInP) 658nm, 5J/cm2 was used to treat the animals in the "treated" groups in scan for 3 consecutive days. Samples were drawn before inoculating bacteria and following laser treatment. For statistical analysis we used the nonparametric Wilcoxon (paired data) method with a significance level of p <0.05. The statistical analysis of median values showed that the groups submitted to laser treatment had low bacterial proliferation. The laser (AlGaInP), with a dose of 5J/cm2 in both intact skin and in wounds of rats infected with Staphylococcus aureus MRSA, is shown to reduce bacterial proliferation. .

Fundamentos: A terapia a laser é um procedimento de baixo custo, não invasiva e com bom desempenho na cicatrização. As dúvidas existentes quanto a sua ação sobre microrganismos justifica a realização de pesquisas visando investigar os possíveis efeitos em feridas infectadas por bactérias. Avaliar o efeito do laser de baixa intensidade sobre a taxa de contaminação bacteriana em feridas infectadas na pele de ratos. Estudo experimental, utilizando 56 ratos machos Wistar. Os animais foram distribuídos aleatoriamente em oito grupos de sete animais. Nos animais dos grupos lesionados foi realizada uma incisão na região dorsal.Os animais dos grupos infectados foram infectados por Staphylococcus aureus MRSA. os animais dos grupos tratados foram tratados com laser de Diodo vermelho (AlGaInP) 658nm, 5J/cm2 em varredura, durante 3 dias consecutivos. Foi colhida uma amostra antes de inocular as bactérias e outra após o tratamento com laser. Para a análise estatística foram utilizados os testes não paramétricos de Wilcoxon (dados pareados). Considerando como significante p<0,05. Através da análise estatística das medianas, observou-se que os grupos submetidos ao laser apresentavam uma proliferação bacteriana menor. O laser (AlGaInP), com uma dose de 5J/cm2, tanto em feridas quanto em pele íntegra de ratos infectados por Staphilococcus aureus MRSA, se mostrou capaz de reduzir a proliferação bacteriana. .

Effect of postoperative radiotherapy on infected prosthetic aortic grafts

A infecçäo de enxertos de prótese vascular apresenta uma mortalidade de 60-100%. Os antibióticos têm pouco efeito nessa complicaçäo. Trabalhos anteriores utilizaram radioterapia no tratamento de gangrena gasosa. Esta investigaçäo apresenta o resultado do uso de 1000 rads no tratamento de enxertos vasculares de Dacron infectados com S. aureus, no cäo. A alta mortalidade sugere que a radiaçäo suprime a medula óssea. Uma radiaçäo menor pode ser necessária para tratar as complicaçöes sépticas.