Interplay between the gastric bacterial microbiota and Candida albicans during postantibiotic recolonization and gastritis

Abstract

The indigenous bacterial microbiome of the stomach, including lactobacilli, is vital in promoting colonization resistance against Candida albicans. However, there are gaps in our understanding about C. albicans gastric colonization versus disease, especially during the postantibiotic recovery phase. This study compared the gastric responses to C. albicans strains CHN1 and SC5314 in microbiome-disturbed and germfree mice to elucidate the contribution of the indigenous microbiota in C. albicans colonization versus disease and yeast-bacterium antagonism during the post-cefoperazone recolonization period. C. albicans can prevent the regrowth of Lactobacillus spp. in the stomach after cefoperazone and promote increased colonization by Enterococcus spp. Using a culture-independent analysis, the effects of oral cefoperazone on the gastric bacterial microbiota were observed to last at least 3 weeks after the cessation of the antibiotic. Disturbance of the gastric bacterial community by cefoperazone alone was not sufficient to cause gastritis, C. albicans colonization was also needed. Gastritis was not evident until after day 7 in cefoperazone-treated infected mice. In contrast, in germfree mice which lack a gastric microbiota, C. albicans induced gastric inflammation within 1 week of inoculation. Therefore, the gastric bacterial community in cefoperazone-treated mice during the first week of postantibiotic recolonization was sufficient to prevent the development of gastritis, despite being ineffective at conferring colonization resistance against C. albicans. Altogether, these data implicate a dichotomy between C. albicans colonization and gastric disease that is bacterial microbiome dependent.

FIG 1

The presence of C. albicans CHN1 during antibiotic recolonization results in elevated fungal colonization of the stomach. The stomach was removed at day 7 and day 21 postantibiotic and differentially cultured to determine C. albicans CHN1 colonization in conventional untreated, antibiotic-treated (Cef), CHN1-colonized alone (CHN1), or cefoperazone-treated CHN1-colonized (Cef/CHN1) mice. Untreated and cefoperazone-only mice had no detectable C. albicans CHN1 colonization. At day 7 postantibiotic, 36% of the CHN1 mice and 100% of the Cef/CHN1 mice had detectable C. albicans CHN1. At day 21 postantibiotic, 9% of the CHN1 mice and 81% of the Cef/CHN1 mice had detectable C. albicans CHN1 in the stomach. Error bars represent the standard errors of the mean. LOD, limit of detection (*, P < 0.05 versus untreated).

FIG 2

C. albicans CHN1 colonization during bacterial recolonization results in long-term gastric erosions at the murine limiting ridge. Histological sections of the murine stomach were stained with H&E to look for evidence of inflammation during cefoperazone-induced microbiota disruption. Untreated mice had no evidence of gastric erosions at any time point. CHN1-colonized mice at day 7 had a low incidence of gastric erosions and, by day 21, no erosions were seen. Cefoperazone-treated CHN1-colonized mice at day 7 had low-grade inflammation that progressed into erosions by day 21.

FIG 3

Hyphal growth at the murine limiting ridge following bacterial dysbiosis. Histological sections of the murine stomach were stained with PAS to detect fungi during antibiotic recolonization. Untreated mice had no fungi present at any time point. Cef/CHN1 mice at day 7 had some detectable hyphal growth, but by day 21 postantibiotic, hyphal growth and invasion were detected at the limiting ridge (magnification, ×100). At higher magnifications, substantial hyphal growth was detected at the area of inflammation at the limiting ridge.

FIG 4

Cefoperazone (Cef) treatment results in long-term alterations in the indigenous bacterial populations of the murine stomach in the presence or absence of C. albicans CHN1. The stomach was removed and analyzed using T-RFLP. Rank abundance plots were constructed from TRFs in each of the experimental groups at day 7 and day 21 postantibiotic. Error bars represent the standard errors of the mean, where the mean is pooled TRFs from individual mice within each experimental group.

FIG 5

C. albicans CHN1 interacts with the indigenous lactic acid bacteria of the murine stomach. The stomach was removed at day 7 (A) and day 21 (B) postantibiotic and differentially cultured to determine total lactic acid bacterium (LAB) colonization levels in conventional untreated, antibiotic-treated (Cef), and Cef/CHN1 mice (graphs). Lactic acid bacterial colonies that grew on MRS plus azide agar were further identified and expressed as a fraction of the total LAB population in that group, using colony PCR as described in the methods (pie charts). Error bars represent the standard errors of the mean (*, P < 0.05 compared to untreated mice).

FIG 6

Cefoperazone (Cef) treatment results in long-term alterations in the indigenous bacterial populations of the murine stomach in the presence or absence of C. albicans SC5314.The stomach was removed and analyzed with T-RFLP. Rank abundance plots were constructed from TRFs in each of the experimental groups at day 7 and day 21 postantibiotic. Error bars represent the standard errors of the mean, where the mean is pooled TRFs from individual mice within each experimental group.

FIG 7

C. albicans SC5314 interacts with the indigenous lactic acid bacteria of the murine stomach. The stomach was removed at day 7 (A) and day 21 (B) postantibiotic and differentially cultured to determine total lactic acid bacterium (LAB) colonization levels in conventional untreated, antibiotic-treated (Cef), and Cef/SC5314 mice (graphs). Lactic acid bacterial colonies that grew on MRS plus azide agar were further identified and expressed as a fraction of the total LAB population in that group, using colony PCR as described in the methods (pie charts). Error bars represent the standard errors of the mean (*, P < 0.05 compared to untreated mice).

FIG 8

The presence of C. albicans SC5314 during cefoperazone recovery results in gastric colonization and erosions of the limiting ridge. The stomach was removed at day 21 postantibiotic and differentially cultured to determine C. albicans SC5314 colonization in conventional untreated, antibiotic-treated (Cef), SC5314-colonized alone (SC5314), or Cef/SC5314 mice (A). Histological sections were stained with H&E to look for evidence of inflammation during cefoperazone-induced microbiota disruption (B). At day 7 postantibiotic, 17% of the SC5314 mice and 83% of the Cef/SC5314 mice had detectable C. albicans CHN1. At day 21 postantibiotic, 20% of the SC5314 mice and 67% of the Cef/SC5314 mice had detectable C. albicans SC5314 in the stomach. LOD, limit of detection (*, P < 0.05 versus untreated).

FIG 9

C. albicans CHN1 and SC5314 effectively colonize germfree mice and result in gastric erosions. The stomach was removed at day 7 and day 21 postantibiotic and differentially cultured to determine C. albicans colonization in germfree mice. (A) All germfree colonized mice had detectable C. albicans at all time points. (B) Histological sections were stained with H&E to look for evidence of inflammation during C. albicans colonization. Germfree mice had no evidence of inflammation or erosions. Germfree mice colonized with CHN1 or SC5314 at day 7 and day 21 all had evidence of gastric inflammation. Error bars represent the standard errors of the mean (*, P < 0.05 versus uninfected).