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Distinct stages during colonization of the mouse gastrointestinal tract by Candida albicans.

Prieto D, Pla J - Front Microbiol (2015)

Bottom Line: Candida albicans is a member of the human microbiota, colonizing both the vaginal and gastrointestinal tracts.This yeast is devoid of a life style outside the human body and the mechanisms underlying the adaptation to the commensal status remain to be determined.We show that long term (15 days) colonizing cells have increased fitness in the gut niche over those grown in vitro or residing in the gut for 1-3 days.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid Madrid, Spain.

ABSTRACT
Candida albicans is a member of the human microbiota, colonizing both the vaginal and gastrointestinal tracts. This yeast is devoid of a life style outside the human body and the mechanisms underlying the adaptation to the commensal status remain to be determined. Using a model of mouse gastrointestinal colonization, we show here that C. albicans stably colonizes the mouse gut in about 3 days starting from a dose as low as 100 cells, reaching steady levels of around 10(7) cells/g of stools. Using fluorescently labeled strains, we have assessed the competition between isogenic populations from different sources in cohoused animals. We show that long term (15 days) colonizing cells have increased fitness in the gut niche over those grown in vitro or residing in the gut for 1-3 days. Therefore, two distinct states, proliferation and adaptation, seem to exist in the adaptation of this fungus to the mouse gut, a result with potential significance in the prophylaxis and treatment of Candida infections.

No MeSH data available.


Related in: MedlinePlus

Influence of the inoculum dose in the colonization levels. After four days of antibiotic treatment, different doses of C. albicans were orally given. (A) Fungal loads in stools (log CFU per gram, mean ± SEM) from each group (n = 2) on days 1 and 3. (B) Relation between levels detected in stools and dose on days 1 and 3 (mean ± SEM).
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Figure 1: Influence of the inoculum dose in the colonization levels. After four days of antibiotic treatment, different doses of C. albicans were orally given. (A) Fungal loads in stools (log CFU per gram, mean ± SEM) from each group (n = 2) on days 1 and 3. (B) Relation between levels detected in stools and dose on days 1 and 3 (mean ± SEM).

Mentions: Treatment of mice with oral antibiotics has been a broadly used strategy to allow high C. albicans colonization levels after gastrointestinal inoculation (Wiesner et al., 2001; Koh, 2013). In these protocols, a high dose of C. albicans is normally given either by a single gavage or via drinking water ad libitum. Oral doses (about 107 CFUs) are in the range of the levels later obtained from stools (106–107 CFUs/g stool). It is normally accepted that a high inoculum may help gut establishment of C. albicans. We tested this assumption by inoculating 5 groups of mice (n = 2) with 100 μL of serial dilutions of a 107 CFUs/mL solution of stationary C. albicans phase cells. Mice therefore received 106, 105, 104, 103, or 102C. albicans cells in a single dose and stool fungal levels were determined in the following days. At day 1, CFUs obtained from stools correlated well with the inoculated dose and were roughly 10x higher (in CFUs/g) than the dose. At day 3, they all reached similar high colonization levels (7.3 ± 0.23, mean of Log (CFU/g) ± SEM), independently of the dose received (Figure 1). Ratios between stool concentration values at day 1 and dose inoculum was found to be very similar for all groups, 1.3 ± 0.15 [Log (CFU/g)/Log (CFU inoculated), mean ± SEM], suggesting that cells proliferated rather similarly during this period. This result indicates that the first 72 h after inoculation are critical for C. albicans to proliferate and attain stable stationary colonization levels which are then properly maintained in the next days. We hypothesized that during this period cells focus on proliferation, while at later stages, C. albicans may rely on adaptation to the new environment.


Distinct stages during colonization of the mouse gastrointestinal tract by Candida albicans.

Prieto D, Pla J - Front Microbiol (2015)

Influence of the inoculum dose in the colonization levels. After four days of antibiotic treatment, different doses of C. albicans were orally given. (A) Fungal loads in stools (log CFU per gram, mean ± SEM) from each group (n = 2) on days 1 and 3. (B) Relation between levels detected in stools and dose on days 1 and 3 (mean ± SEM).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525673&req=5

Figure 1: Influence of the inoculum dose in the colonization levels. After four days of antibiotic treatment, different doses of C. albicans were orally given. (A) Fungal loads in stools (log CFU per gram, mean ± SEM) from each group (n = 2) on days 1 and 3. (B) Relation between levels detected in stools and dose on days 1 and 3 (mean ± SEM).
Mentions: Treatment of mice with oral antibiotics has been a broadly used strategy to allow high C. albicans colonization levels after gastrointestinal inoculation (Wiesner et al., 2001; Koh, 2013). In these protocols, a high dose of C. albicans is normally given either by a single gavage or via drinking water ad libitum. Oral doses (about 107 CFUs) are in the range of the levels later obtained from stools (106–107 CFUs/g stool). It is normally accepted that a high inoculum may help gut establishment of C. albicans. We tested this assumption by inoculating 5 groups of mice (n = 2) with 100 μL of serial dilutions of a 107 CFUs/mL solution of stationary C. albicans phase cells. Mice therefore received 106, 105, 104, 103, or 102C. albicans cells in a single dose and stool fungal levels were determined in the following days. At day 1, CFUs obtained from stools correlated well with the inoculated dose and were roughly 10x higher (in CFUs/g) than the dose. At day 3, they all reached similar high colonization levels (7.3 ± 0.23, mean of Log (CFU/g) ± SEM), independently of the dose received (Figure 1). Ratios between stool concentration values at day 1 and dose inoculum was found to be very similar for all groups, 1.3 ± 0.15 [Log (CFU/g)/Log (CFU inoculated), mean ± SEM], suggesting that cells proliferated rather similarly during this period. This result indicates that the first 72 h after inoculation are critical for C. albicans to proliferate and attain stable stationary colonization levels which are then properly maintained in the next days. We hypothesized that during this period cells focus on proliferation, while at later stages, C. albicans may rely on adaptation to the new environment.

Bottom Line: Candida albicans is a member of the human microbiota, colonizing both the vaginal and gastrointestinal tracts.This yeast is devoid of a life style outside the human body and the mechanisms underlying the adaptation to the commensal status remain to be determined.We show that long term (15 days) colonizing cells have increased fitness in the gut niche over those grown in vitro or residing in the gut for 1-3 days.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid Madrid, Spain.

ABSTRACT
Candida albicans is a member of the human microbiota, colonizing both the vaginal and gastrointestinal tracts. This yeast is devoid of a life style outside the human body and the mechanisms underlying the adaptation to the commensal status remain to be determined. Using a model of mouse gastrointestinal colonization, we show here that C. albicans stably colonizes the mouse gut in about 3 days starting from a dose as low as 100 cells, reaching steady levels of around 10(7) cells/g of stools. Using fluorescently labeled strains, we have assessed the competition between isogenic populations from different sources in cohoused animals. We show that long term (15 days) colonizing cells have increased fitness in the gut niche over those grown in vitro or residing in the gut for 1-3 days. Therefore, two distinct states, proliferation and adaptation, seem to exist in the adaptation of this fungus to the mouse gut, a result with potential significance in the prophylaxis and treatment of Candida infections.

No MeSH data available.


Related in: MedlinePlus