Journal Article

Global and Historical Distribution of Clostridioides difficile in the Human Diet (1981–2019): Systematic Review and Meta-Analysis of 21886 Samples Reveal Sources of Heterogeneity, High-Risk Foods, and Unexpected Higher Prevalence Toward the Tropic

Rodriguez-Palacios, Alexander, Bijedic, Nina, Ilic, Sanja, Msuya, Joan, Shah, Bhavan U., Mo, Kevin Q., Deshpande, Abhishek

2020

Overview

(CD) is a spore-forming bacterium that causes life-threatening intestinal infections in humans. Although formerly regarded as exclusively nosocomial, there is increasing genomic evidence that person-to-person transmission accounts for only <25% of cases, supporting the culture-based hypothesis that foods may be routine sources of CD-spore ingestion in humans. To synthesize the evidence on the risk of CD exposure via foods, we conducted a systematic review and meta-analysis of studies reporting the culture prevalence of CD in foods between January 1981 and November 2019. Meta-analyses, risk-ratio estimates, and meta-regression were used to estimate weighed-prevalence across studies and food types to identify laboratory and geographical sources of heterogeneity. In total, 21886 food samples were tested for CD between 1981 and 2019 (96.4%, = 21084, 2007-2019; 232 food-sample-sets; 79 studies; 25 countries). Culture methodology, sample size and type, region, and latitude were sources of heterogeneity ( < 0.05). Although non-strictly-anaerobic methods were reported in some studies, and we confirmed experimentally that improper anaerobiosis of media/sample-handling affects CD recovery in agar (Fisher, < 0.01), most studies (>72%) employed the same (one-of-six) culture strategy. Because the prevalence was also meta-analytically similar across six culture strategies reported, all studies were integrated using three meta-analytical methods. At the study level ( = 79), the four-decade global cumulative-prevalence of CD in the human diet was 4.1% (95%CI = -3.71, 11.91). At the food-set level ( = 232, mean 12.9 g/sample, similar across regions > 0.2; 95%CI = 9.7-16.2), the weighted prevalence ranged between 4.5% (95%CI = 3-6%; all studies) and 8% (95%CI = 7-8%; only CD-positive-studies). Risk-ratio ranking and meta-regression showed that milk was the least likely source of CD, while seafood, leafy green vegetables, pork, and poultry carried higher risks ( < 0.05). Across regions, the risk of CD in foods for foodborne exposure reproducibly decreased with Earth latitude ( < 0.001). In conclusion, CD in the human diet is a global non-random-source of foodborne exposure that occurs independently of laboratory culture methods, across regions, and at a variable level depending on food type and latitude. The latitudinal trend (high CD-food-prevalence toward tropic) is unexpectedly inverse to the epidemiological observations of CD-infections in humans (frequent in temperate regions). Findings suggest the plausible hypothesis that ecologically-richer microbiomes in the tropic might protect against intestinal CD colonization/infections despite CD ingestion.

• Publisher: Frontiers Media SA,Frontiers Media S.A
• Subject: Beef / C. difficile / Citation management software / difficile / Epidemics / epidemiology / food / Food contamination & poisoning / global / Infections / Inflammatory bowel disease / Laboratories / Medicine / Meta-analysis / one health / Search strategies / Systematic review / Trends