Inactivació de S. aureus amb rosa de Bengala i gentamicina in vitro: influència de l’ús del tampó fosfat salí o del caldo tripticasa soja


Carbonero i Navarro, Helena 


During the last years an inadequate and excessive use of antibiotics had been done. This fact has caused an increasing microbial resistance towards them. To face this problem, apart from raising the awareness to the population, alternative therapies are being researched. A proposal is Photodynamic Therapy (PDT), non-toxic dyes or Photosensitizers (PS) in combination with a harmless visible light, which used at same time produce reactive oxygen species (ROS), and cell death. Nowadays, combined therapy studies are being carried out, that means, combining the effect of a PS with an antibiotic. The photosensitizer used in this TFG has been Rose Bengal, and consequently, the light used green. The chosen antibiotic has been gentamicin. In the in vitro studies about the application of PDT normally use PBS. However, taking in account the use of an antibiotic is thought that we could have a better efficacy using TSB. The objective of this TFG is to study which would be better for a combined therapy. The bacterial strain Staphylococcus aureus had been chosen and treated with photosensitizer, antibiotic, or combination therapy. Each of these procedures was performed on both, PBS and TSB media. Results have been in the following: Procedures where the samples were only treated with photoinactivator worked best with the usual medium, PBS, where the cells were suspended during treatment. Procedures where only treated with antibiotic have performed better with TSB. However, the statistical tests showed that these differences were not significant. The PTD of the samples subjected to RB + G LIGHT treatment did not show significant differences between PBS and TSB. In conclusion we can say that, given the results obtained, it is preferable to use PBS buffer in the combination therapy with antibiotic (gentamicin) and photosensitizer (Bengal rose).



Agut Bonsfills, Montserrat
Nonell i Marrugat, Santiago  


IQS SE - Undergraduate Program in Biotechnology