Dietary zinc alters the microbiota and decreases resistance to Clostridium difficile infection

Abstract

Clostridium difficile is the most commonly reported nosocomial pathogen in the United States and is an urgent public health concern worldwide1. Over the past decade, incidence, severity, and costs associated with C. difficile infection (CDI) have increased dramatically2. CDI is most commonly initiated by antibiotic-mediated disruption of the gut microbiota; however, non-antibiotic associated CDI cases are well documented and on the rise3,4. This suggests that unexplored environmental, nutrient, and host factors likely influence CDI. Here we show that excess dietary zinc (Zn) significantly alters the gut microbiota and in turn reduces the threshold of antibiotics needed to confer susceptibility to C. difficile infection. In mice colonized with C. difficile, excess dietary Zn severely exacerbates C. difficile-associated disease by increasing toxin activity and altering the host immune response. In addition, we show that the Zn binding S100 protein calprotectin is antimicrobial against C. difficile and an essential component of the innate immune response to CDI. Together, these data suggest that nutrient Zn levels play a key role in determining susceptibility to CDI and severity of disease, and that calprotectin-mediated metal limitation is an important factor in the host immune response to C. difficile.

Dietary Manganese Promotes Staphylococcal Infection of the Heart

“…Mice were subjected to a previously described model of C. difficile infection (Zackular et al, 2016). Briefly, mice were given cefoperazone in their drinking water (0.5 mg/ml) for five days.…”

“…Sections were stained with hemotoxylin and eosin. Each section was given a disease score by a pathologist in a blinded fashion based on previously described criteria (Zackular et al, 2016). Specifically, histological scores were reported as a cumulative score of three independent scoring criteria: inflammation, edema, and epithelial cell damage.…”

“…DNA was isolated from fecal samples using the PowerSoil DNA isolation kit (MO BIO Laboratories). For each sample, the V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq Personal Sequencing platform and sequences were curated using the mothur software package, as previously described (Schloss et al, 2009; Zackular et al, 2016). After curation, we obtained between 8,297 and 23,327 sequences per sample (median=13,015), with a median length of 253 bp.…”

“…However, nutritional immunity can be overwhelmed by dietary metal intake. Dietary Fe supplementation enhances Mycobacterium avium infection in mice (Dhople et al, 1996), and excess dietary Zn allows Clostridium difficile to overcome host Zn sequestration (Zackular et al, 2016). These studies suggest that nutritional immunity is limited in its capacity to sequester dietary metals, and excess dietary Mn may affect the outcome of infection.…”

The emerging metabolic view of Clostridium difficile pathogenesis

“…It was shown that dietary zinc plays a key role in determining CDI susceptibility and severity of disease [40] and that low protein diets are protective against CDI in mice [41]. Other studies highlighted the inhibitory effects of microbiota accessible carbohydrates (MACs) on C. difficile fitness by co-culturing C. difficile with Bifidobacterium spp.…”