Candida is a genus of opportunistic fungi that can cause
infection in humans. These fungi are plentiful in nature and are commonly found
in soil, on plants, and on other fomites. It reproduces asexually through budding but it
is highly variable and adaptable due to its dimorphic nature, allowing it to be
in the form of yeast or mold. There are over 150 species of Candida but only 20
are considered pathogens in mammals (Candidiasis). Candida yeasts are found on
the skin, mucous membranes, and reside in the intestinal tract.
The fungal infection of Candida
species in humans and animals is known as Candidiasis. The most common species
of Candida that causes infection is Candida albicans.
This species is also commonly found in the gut flora of around half of healthy
adults. The presence of the yeast is not enough to cause issue due to the
protective barriers of mammals including skin and mucous membranes, but
overgrowth can break down these barriers and enter into the bloodstream (Candidiasis).
Overgrowth occurs because Candida is dimorphic and has the ability to switch
between yeast and hyphal growth forms (Hawley, H. Bradford, MD.). These different growth forms have special functions
that allow for better adhesion, invasion, damage, dissemination, immune evasion
and host response (Jacobsen, I D, et al.). This is the cause for much of the fungi’s
virulence and adaptation against treatment.
Common infections caused by Candida
are oral candidiasis and vaginal candidiasis. The iGEM team’s project is
focused on vaginal candidiasis, also known as yeast infections. The symptoms of
vaginal candidiasis include abnormal vaginal discharge, vaginal itch or
soreness, pain or discomfort during intercourse or urination (Vaginal
Candidiasis). Yeast infections are the overgrowth of Candida in the mucosal
membranes of the vagina caused by favorable changes in the environment for the
yeast. The risk for Candidiasis is greater when the immune system is
compromised or when microbial populations in the body change (Candidiasis).
The current options for detection of
Candida in the case of a possible fungal infection include vaginal discharge
samples that are placed under a microscope for identification of the fungi
amongst the natural flora and lab testing to check for fungal cultures. Diagnosis
is difficult because Candida can be naturally occurring in the body. Therefore,
laboratory testing that is positive for a fungal culture does not conclusively determine
that Candida is the cause (Vaginal Candidiasis). The treatment for candidiasis
includes oral and topical anti-fungal medication. The topical anti-fungal
medication is used for temporary overgrowth but if the infection is persistent,
long-term oral treatments such as six-month rounds of Fluconazole are used.
The experimental design is still in
the process of being determined. Our current plan is to grow Candida species in
the lab and determine what antigens would be good targets for identification.
The goal is to create a simple at-home test similar to a pregnancy test where
the presence of the Candida species will be indicated through some type of
color change in order for the user to determine the presence of a fungal
infection and gain access to proper care.
Overall, Candida infections are
impactful to everyone based on the multiple routes of infection to include the
skin, oral cavity, bloodstream, gastrointestinal tract, and vaginal cavity. It
is the most common fungal infection in humans and it can be difficult to treat
due to its recurring nature.
The military impact of fungal
infections caused by Candida is significant, especially during training or
deployments. The main reason for this is inadequate access to restrooms and
proper hygiene. Receiving the proper treatment for this infection can be
difficult due to decreased access to medical care, time-consuming labs, and
long term anti-fungal medications.