In this study, Candida albicans in its planktonic form, was used as target microorganism. This species frequently appears in superficial and invasive infections because of its pathogenic potential, and it is becoming highly resistant. Bacteriochlorin was used as a photosensitizer, presenting absorption around 780 nm and low toxicity in the absence of light. The objective was to evaluate its photodynamic inactivation potential in Candida albicans. The photosensitizer was synthesized from the extraction of bacteriochlorophylls derived from non-sulfurous purple bacteria and the converted to bacteriochlorin. The inoculum of Candida albicans was grown for 24 hours and adjusted to the concentration of 106 CFU/mL. The device used for the emission of light was a homemade device with LEDs of 780 nm wavelength. The quantitative evaluation of viable cells was performed by spread plate in Sabouraud Dextrose Agar. The results showed that this new bacteriochlorin is not much stable in its absorption peak, being necessary a better chemical characterization to verify its antimicrobial potential.
In this study, we used bacteriochlorin as a photosensitizer, characterized by their low toxicity in the absence of light, presenting absorption around 780 nm, with the objective of evaluating their photodynamic inactivation potential on Staphylococcus aureus and Escherichia coli. Bacteriochlorins were synthesized from the extraction of bacteriochlorophylls from non-sulfurous purple bacteria and were then converted to bacteriochlorins. S. aureus and E. coli microorganisms were used in the planktonic and biofilm forms. For the formation of biofilms on glass coverslips, suspensions of the microorganisms at the concentration of 106 CFU/mL were inoculated into each well of a microplate. There was an exchange of culture medium (Tryptic Soy Broth - TSB) every 24 hours for 7 days, pre-washing the coverslips with a phosphate-buffered saline (PBS), to ensure that only adhered microorganisms were grown and then incubated at (36 ± 1)°C between the middle exchanges. After 7 days of induction, the biofilm was mature, like those normally found in nature, and then it was applied different treatments (light doses associated with FS concentrations). At the end of the treatment, the coverslips underwent an ultrasonic disintegration, and the quantitative evaluation of viable cells was performed by plate counting using the plate method in Tryptic Soy Agar (TSA), incubating at (36 ± 1)°C for 24 hours. The results showed that the PDI for E. coli was not successful even when it was more susceptible to the planktonic form, whereas for S. aureus the results showed a reduction in cell viability 6 logs for the planktonic forms, but lower to 1 log in biofilms. Therefore, novel studies using bacteriochlorins and surfactants will be performed to verify the potential of this alternative treatment method.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.