Banca de QUALIFICAÇÃO: ANA BEATRIZ NASCIMENTO DE MACEDO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANA BEATRIZ NASCIMENTO DE MACEDO
DATE: 18/12/2023
TIME: 14:00
LOCAL: Google meet: https://meet.google.com/waz-ysfh-otc
TITLE:

METABOLIC INTERACTION BETWEEN THE FUNGUS Candida auris AND THE BACTERIA
Pseudomonas aeruginosa

KEY WORDS:

Candida auris; Antagonistic Actions; Microbial Interactions; Pseudomonas
aeruginosa; Secondary metabolites.

PAGES: 63
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

In hospital environments, a range of microorganisms that are harmful to human
health can be found and due to certain situations, such as invasive procedures, hospital infections have the potential
to occur. Among them, we can find Pseudomonas aerugensa, which is a gram-negative bacillus that does not ferment
glucose and carbohydrates, is mobile, oxidase positive and has a great capacity to form biofilms, being found
ubiquitously in nature, including aquatic and terrestrial environments, in animals, plants and humans. It stands out
for its phenotypic plasticity, ability to survive in various environments and its resistance to medications, antiseptics
and disinfectants. In the hospital context, we also find Candida auris, an emerging pathogenic fungus, as well as some
bacteria, which is quite resistant to hospital disinfection and difficult to control in hospitals. In this scenario, little is
known about how C. auris interacts with such bacteria in the hospital environment and in the host. Therefore, the
objective of this work was to study the interaction between Candida auris and Candida albicans with the bacterium
Pseudomonas aeruginosa. Initially, it was investigated whether there was antagonism between C. albicans and P.
aeruginosa through co-cultivation in liquid medium, showing that P. aeruginosa significantly inhibited the growth of
the yeast. It was then demonstrated that P. aeruginosa significantly inhibited the growth of both C. albicans and C.
auris, and that this phenomenon was independent of the yeast concentration used in co-cultivation (4 - 6 log cycles).
In the kinetics experiment, it was observed that inhibition begins at 8 hours and continues until 72 hours, which was
the maximum tested in this experiment. And once the bacteria was able to inhibit the growth of yeast, it was tested
whether the inhibition was just the result of competition for nutrients by doing the same experiment, but now using a
chemically defined medium (RPMI), a complex medium (more nutrient-rich) (YPD) and also adding other nutrients to
the medium, such as 2% glucose and iron concentrations (30 µM to 480 µM). The results showed that P. aeruginosa
inhibited the growth of C. albicans and C. auris (1-2 log cycles) with no statistical difference between the inhibition
comparing the use of both media, however it was observed that in the presence of iron the inhibition decreased
compared to the control. It is concluded, therefore, that P. aeruginosa (Pa14) inhibits the growth of C. albicans and C.
auris similarly, and that this process needs to be better characterized, and can be directly influenced due to the
production of antagonistic substances with antifungal activity, or competition for nutrients important for your
metabolism.

COMMITTEE MEMBERS:
Presidente - 1143204 - RAFAEL WESLEY BASTOS
Externa à Instituição - LUANA ROSSATO
Externa à Instituição - REGINA LÚCIA BALDINI - USP