Characterization of Food Chain Clostridioides difficile Isolates in Terms of Ribotype and Antimicrobial Resistance

The aim of this study was to characterize C. difficile isolates from the farm, abattoir, and retail outlets in Ireland in terms of ribotype and antibiotic resistance (vancomycin, erythromycin, metronidazole, moxifloxacin, clindamycin, and rifampicin) using PCR and E-test methods, respectively. The most common ribotype in all stages of the food chain (including retail foods) was 078 and a variant (RT078/4). Less commonly reported (014/0, 002/1, 049, and 205) and novel (RT530, 547, and 683) ribotypes were also detected, but at lower frequencies. Approximately 72% (26/36 tested) of the isolates tested were resistant to at least one antibiotic, with the majority of these (65%; 17/26) displaying a multi-drug (three to five antibiotics) resistant phenotype. It was concluded that ribotype 078, a hypervirulent strain commonly associated with C. difficile infection (CDI) in Ireland, was the most frequent ribotype along the food chain, resistance to clinically important antibiotics was common in C. difficile food chain isolates, and there was no relationship between ribotype and antibiotic resistance profile.

Global prevalence of Clostridioides difficile in 17,148 food samples from 2009 to 2019: a systematic review and meta-analysis

BACKGROUND

Clostridioides (Clostridium) difficile is an important infectious pathogen, which causes mild-to-severe gastrointestinal infections by creating resistant spores and producing toxins. Spores contaminated foods might be one of the most significant transmission ways of C. difficile-associated infections. This systematic review and meta-analysis study were conducted to investigate the prevalence of C. difficile in food.

METHODS

Articles that published the prevalence of C. difficile in food in PubMed, Web of Science, and Scopus databases were retrieved using selected keywords between January 2009 and December 2019. Finally, 17,148 food samples from 60 studies from 20 countries were evaluated.

RESULTS

The overall prevalence of C. difficile in various foods was 6.3%. The highest and lowest levels of C. difficile contamination were detected to seafood (10.3%) and side dishes (0.8%), respectively. The prevalence of C. difficile was 4% in cooked food, 6.2% in cooked chicken and 10% in cooked seafood.

CONCLUSIONS

There is still little known concerning the food-borne impact of C. difficile, but the reported contamination might pose a public health risk. Therefore, to improve the food safety and prevent contamination with C. difficile spores, it is necessary to observe hygienic issues during foods preparation, cooking and transfer.

Clostridioides difficile in Foods with Animal Origins; Prevalence, Toxigenic Genes, Ribotyping Profile, and Antimicrobial Resistance

Clostridioides difficile is an important nosocomial pathogen and is considered as a reason of diarrhea and gastrointestinal infections. As a majority of community-originated C. difficile cases are not related to antibiotic prescription and hospitalization, the food portion as a vector of infection transmission has been raised. An existing survey was aimed evaluating the prevalence, antimicrobial resistance, profile of toxigenic genes, and ribotypes of C. difficile isolated from raw meat and carcass surface swab samples. In total, 485 raw meat and carcass surface swab samples were collected. C. difficile was isolated via culture and a diverse biochemical examination. The assessment of minimum inhibitory concentration (MIC) was addressed to evaluate the antibiotic resistance of isolates. Toxin genes detection and ribotyping were used for isolates characterization. The prevalence of C. difficile contamination in all examined samples was 3.71%. The bacterium was detected in 2.91% of raw meat and 4.48% of carcass surface swab samples. Raw sheep meat (5%) and sheep carcass swab (7.50%) samples harbored the highest C. difficile prevalence. The highest rate of antibiotic resistance was observed toward clindamycin (38.88%), ciprofloxacin (38.88%), metronidazole (44.44%), erythromycin (72.22%), and tetracycline (77.77%). C. difficile bacteria showed the minimum rate of resistance meropenem (16.66%) and chloramphenicol (16.66%). TcdA, tcdB, cdtA, and cdtB toxigenic genes were detected in 22.22%, 44.44%, and 16.66% of isolates, respectively. TcdB + tcdA (27.77%) were the most prevalent combined toxigenic gene profile. Both 027 and 078 ribotypes were identified in C. difficile isolates. The role of raw meat and carcass surface swab samples as toxigenic and antibiotic-resistant C. difficile strains vectors was signified. This study authorizes that food animals, particularly sheep and cattle, are C. difficile carriers at slaughter stages and ribotypes are equal in human cases. Subsequently, contamination of carcasses occurs inside the slaughterhouse.

Clostridioides difficile infection (CDI) during the COVID-19 pandemic

The ongoing coronavirus disease (COVID-19) pandemic has dramatically tested healthcare systems around the world, with serious repercussions on the measures of prevention and control of hospital-acquired infections (HAIs). Among HAIs, Clostridioides difficile infection (CDI) represents one of the most important global public health threats. Although the full impact of the COVID-19 pandemic on CDI remains undetermined, depending on the development of the pandemic in the coming months, in this review literature studies of the last three years have been considered in order to depict the current situation, and make some considerations about possible future developments. If on the one hand, a general reduction in CDI incidence has been reported in several settings, mainly due to the extraordinary reinforcement of infection prevention measures, on the other hand, the critical circumstances experienced in many hospitals have limited the effectiveness of these measures, particularly in the intensive care units (ICUs), increasing the possibility of the occurrence of hospital-acquired CDI (HA-CDI). New concerns have arisen from the decrease in C. difficile testing and the increased use of broad-spectrum antibiotics reported during the pandemic. In particular, overuse of antibiotics and disinfectants may lead to a selection of resistant C. difficile strains not only in hospitals but also in the community. Furthermore, patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and patients that have survived COVID-19 may represent a new group of frail patients potentially at a higher risk of CDI, a group that could potentially increase in size due to SARS-CoV-2 evolution. In the dramatic COVID-19 era, the multifactorial nature of CDI has emerged more clearly than before, highlighting the necessity of a strong refocus on efforts to improve prevention strategies and to integrate CDI surveillance in a One Health prospective in order to curtail the public health threat posed by this infection in the next future.

Occurrence of antibiotic-resistant bacteria on hydroponically grown butterhead lettuce (Lactuca sativa var. capitata)

Antibiotics used during production of food crops to control plant diseases may result in selection of antibiotic-resistant bacteria and occurrence of antibiotic residues. The aim of this research was to evaluate the effect of antibiotics used in butterhead lettuce production on persistence of commensal microbiota. Butterhead lettuce were treated with antibiotics (oxytetracycline, gentamicin, and streptomycin) at different concentrations (100, 200, 300, 400 and 500 ppm) starting at 5 weeks' growth by spraying once daily for 4 weeks and harvesting 7 days after the final spray application. The population of total aerobic bacteria and antibiotic-resistant bacteria were determined. The results showed antibiotic usage significantly decreased bacterial populations on lettuce. Moreover, increased concentration of antibiotics resulted in significantly greater decrease in bacterial populations. At a concentration of 500 ppm, all antibiotics achieved an approximate 2 log CFU/g decrease in bacterial populations. A stable population (4 log CFU/g) of potentially antibiotic-resistant commensal microbiota were maintained throughout production. Screening for level of susceptibility indicated that bacteria exhibited greater resistance to oxytetracycline than gentamicin. In conclusion, application of antibiotics failed to eliminate commensal microbiota, demonstrating large populations of antibiotic-resistant bacteria reside on lettuce grown under conditions used in the present study. This is the first study focused on antibiotic usage on hydroponic systems. Results of this study suggest regulations directed at antibiotic use on food crops must be developed and implemented to control the selection and spread of antibiotic-resistant bacteria that present a global health concern.

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

Clostridioides difficile (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%, n = 21084, 2007–2019; 232 food-sample-sets; 79 studies; 25 countries). Culture methodology, sample size and type, region, and latitude were sources of heterogeneity (p < 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, p < 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 (n = 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 (n = 232, mean 12.9 g/sample, similar across regions p > 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 (p < 0.05). Across regions, the risk of CD in foods for foodborne exposure reproducibly decreased with Earth latitude (p < 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.

Prevalence and Molecular Characteristics of Clostridium difficile in Retail Meats, Food-Producing and Companion Animals, and Humans in Minnesota

Community-associated Clostridium difficile infection (CA-CDI) now accounts for approximately 50% of CDI cases in central Minnesota; animals and meat products are potential sources. From November 2011 to July 2013, we cultured retail meat products and fecal samples from food-producing and companion animals in central Minnesota for C. difficile by using standard methods. The resulting 51 C. difficile isolates, plus 30 archived local veterinary C. difficile isolates and 208 human CA-CDI case isolates from central Minnesota (from 2012) from the Minnesota Department of Health, were characterized molecularly, and source groups were compared using discriminant analysis. C. difficile was recovered from 0 (0%) of 342 retail meat samples and 51 (9%) of 559 animal fecal samples. Overall, the 81 animal source isolates and 208 human source isolates were highly diverse genetically. Molecular traits segregated extensively in relation to animal versus human origin. Discriminant analysis classified 95% of isolates correctly by source group; only five (2.5%) human source isolates were classified as animal source. These data do not support meat products or food-producing and companion animals as important sources of CA-CDI in the central Minnesota study region.