ALTERNATIVE THERAPIES IN THE CONTROL OF SUPERINFECTIOUS AND OPPORTUNISTIC MICROORGANISMS IN THE ORAL ENVIRONMENT
Alternative therapies; Microbiology; Antimicrobial photodynamic therapy; Methylene blue; Lactobacillus rhamnosus; Spondias mombin L.
Opportunistic microorganisms establish infectious processes when the host's immune conditions are compromised. Within this group are superinfecting microorganisms, which rapidly proliferate when part of the resident microbiota is suppressed and are known for their resistance to most antimicrobials. To reduce these microorganisms and control infectious processes, there is ongoing research into alternative and complementary therapies. This study aims to compare the in vitro antimicrobial action of three treatments: antimicrobial photodynamic therapy (TFDA) using methylene blue, phytotherapy with the hydroethanolic extract of Spondias mombin L. (ESM) at a concentration of 500 µm/ml, and the probiotic Lactobacillus rhamnosus (PLR) in controlling superinfecting and opportunistic microorganisms such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae. To this end, we investigated microbial growth inhibitory activity, anti-adhesion effects, and antibiofilm activity in mono- and multispecies biofilms using these three therapies, with 0.12% chlorhexidine digluconate (CLO) as a positive control. For statistical analysis, we employed descriptive interpretation and applied the Two-Way ANOVA and Tukey's test, with the significance level set at p < 0.05. The results revealed that, regarding microbial growth inhibition, TFDA, although without statistical significance (p > 0.05), inhibited the growth of A. baumannii and K. pneumoniae, acting similarly on both bacteria. PLR, on the other hand, exhibited inhibitory effects on all tested microorganisms, with no statistical differences (p > 0.05) between A. baumannii and K. pneumoniae, nor were there statistically significant differences (p > 0.05) between PLR and CLO for these two bacteria. In terms of anti-adhesion effects, TFDA showed the best results against K. pneumoniae, while PLR was most effective against P. aeruginosa, with results closely resembling those of CLO in antibiofilm activity. For single-species biofilms, statistically significant differences (p < 0.05) were observed among experimental groups against the studied bacteria. Of the three therapies tested, PLR was the only one that did not show statistically significant differences (p > 0.05) compared to CLO for any of the microorganisms, presenting results very similar to those of CLO. For multispecies biofilms, statistically significant differences (p < 0.05) were observed between the groups, with PLR showing the best results, equivalent to those of CLO. In conclusion, TFDA and PLR were the most effective therapies for microbial control, with PLR being particularly effective, exhibiting growth inhibitory, anti-adhesion, and antibiofilm activities similar to CLO.