Clostridioides difficile ribotypes 001 and 126 were predominant in Tehran healthcare settings from 2004 to 2018: a 14-year-long cross-sectional study

PPAR-γ agonist mitigates intestinal barrier dysfunction and inflammation induced by Clostridioides difficile SlpA in vitro

Clostridioides difficile is the leading cause of healthcare- and antibiotic-associated diarrhea. Surface layer protein A (SlpA), an essential component of the bacterium's outermost layer, contributes to colonization and inflammation. The peroxisome proliferator-activated receptor gamma (PPAR-γ) has been demonstrated to improve intestinal integrity and prevent inflammation in host cells. Here, we investigated the role of PPAR-γ in SlpA-mediated inflammation in Caco-2 cells and THP-1 derived macrophages. The extraction of SlpA was carried out for three toxigenic C. difficile clinical strains (RT126, RT001, RT084) and a non-toxigenic strain (ATCC 700057). The gene expression of tight junction (TJ) proteins and inflammatory markers was determined using RT-qPCR. The production of proinflammatory cytokines and nitric oxide was measured by ELISA and Griss reaction, respectively. Western blotting was performed to detect PPAR-γ level before and after adding its agonist, pioglitazone. SlpA of C. difficile strains enhanced the expression of TLR-4, NF-κB, MyD88, IL-17, MCP-1, IL-8, IL-6, TNF-α, IL-1β, whilst the gene expression level of JAM-A, claudin-1, occludin, PPAR-γ and its receptor (CD36) was decreased in both Caco-2 cells and THP-1 derived macrophages. Moreover, pioglitazone caused a notable elevation in the expression level of PPAR-γ, only following treatment with RT126 SlpA. Besides, pioglitazone pretreatment improved TJ impairment in Caco-2 cells and attenuated proinflammatory cytokine expression in both SlpA-treated cell lines. SlpA can attenuate PPAR-γ expression, trigger TJ disruption, and stimulate inflammatory response in host cells. Notably, these events could be reversed by pretreatment of cells with PPAR-γ agonist. Further experiments are required to corroborate the present findings.

Best Practices in the Management of Clostridioides difficile Infection in Developing Nations

Clostridioides difficile infection (CDI) is a well-known cause of hospital-acquired infectious diarrhea in developed countries, though it has not been a top priority in the healthcare policies of developing countries. In the last decade, several studies have reported a wide range of CDI rates between 1.3% and 96% in developing nations, raising the concern that this could represent a healthcare threat for these nations. This review defines developing countries as those with a human development index (HDI) below 0.8. We aim to report the available literature on CDI epidemiology, diagnostics, management, and prevention in developing countries. We identify limitations for CDI diagnosis and management, such as limited access to CDI tests and unavailable oral vancomycin formulation, and identify opportunities to enhance CDI care, such as increased molecular test capabilities and creative solutions for CDI. We also discuss infection prevention strategies, including antimicrobial stewardship programs and opportunities emerging from the COVID-19 pandemic, which could impact CDI care.

An ultrasensitive genosensor for detection of toxigenic and non-toxigenic Clostridioides difficile based on a conserved sequence in surface layer protein coding gene

Clostridioides difficile (C. difficile) is the most common agent of antibiotic-associated diarrhea, leading to intestinal infection through the secretion of two major toxins. Not all strains of this bacterium are toxigenic, but some of them cause infection via their accessory virulence factors, such as surface layer protein (SlpA). SlpA is conserved in both toxigenic and non-toxigenic strains of C. difficile. In the present work, an amplification-free electrochemical genosensor was designed for the detection of the slpA gene. A glassy carbon electrode coated with gold nanoparticle-reduced graphene oxide nanocomposite was used as the working electrode, and its surface was modified using a simple thiolated linear oligonucleotide as the bioreceptor. Moreover, the hexaferrocenium tri[hexa(isothiocyanato) iron(III)] trihydroxonium (HxFc) complex was used as an intercalator, and its redox signal was recorded using differential pulse voltammetry. Scan rate studies indicated a quasi-reversible adsorption-controlled process for the HxFc complex. This genosensor showed high sensitivity with a limit of detection of 0.2 fM, a linear response range of 0.46-1900 fM, and a satisfactory specificity toward the synthetic slpA target gene. Also, the genosensor indicated responses in the mentioned linear range toward the genome extracted from either toxigenic or non-toxigenic strains of C. difficile.

The anti-inflammatory and anti-apoptotic effects of Achillea millefolium L. extracts on Clostridioides difficile ribotype 001 in human intestinal epithelial cells

BACKGROUND

Clostridioides difficile infection (CDI) is one of the most common health care-acquired infections. The dramatic increase in antimicrobial resistance of C. difficile isolates has led to growing demand to seek new alternative medicines against CDI. Achillea millefolium L. extracts exhibit strong biological activity to be considered as potential therapeutic agents. In this work, the inhibitory effects of A. millefolium, its decoction (DEC) and ethanol (ETOH) extracts, were investigated on the growth of C. difficile RT001 and its toxigenic cell-free supernatant (Tox-S) induced inflammation and apoptosis.

METHODS

Phytochemical analysis of extracts was performed by HPLC and GC analysis. The antimicrobial properties of extracts were evaluated against C. difficile RT001. Cell viability and cytotoxicity of Caco-2 and Vero cells treated with various concentrations of extracts and Tox-S were examined by MTT assay and microscopy, respectively. Anti-inflammatory and anti-apoptotic effects of extracts were assessed in Tox-S stimulated Caco-2 cells by RT-qPCR.

RESULTS

Analysis of the phytochemical profile of extracts revealed that the main component identified in both extracts was chlorogenic acid. Both extracts displayed significant antimicrobial activity against C. difficile RT001. Moreover, both extracts at concentration 50 µg/mL had no significant effect on cell viability compared to untreated cells. Pre-treatment of cells with extracts (50 µg/mL) significantly reduced the percentage of Vero cells rounding induced by Tox-S. Also, both pre-treatment and co-treatment of Tox-S stimulated Caco-2 cells with extracts significantly downregulated the gene expression level of IL-8, IL-1β, TNF-α, TGF-β, iNOS, Bax, caspase-9 and caspase-3 and upregulated the expression level of Bcl-2.

CONCLUSION

The results of the present study for the first time demonstrate the antimicrobial activity and protective effects of A. millefolium extracts on inflammatory response and apoptosis induced by Tox-S from C. difficile RT001 clinical strain in vitro. Further research is needed to evaluate the potential application of A. millefolium extracts as supplementary medicine for CDI prevention and treatment in clinical setting.

Comparison of toxin gene expression levels and molecular typing of Clostridioides difficile strains isolated from patients with diarrhea

Aim

This study aimed to evaluate the expression of tcdA, tcdB, and binary toxin genes (cdtA and cdtB) by Real-Time PCR and molecular typing of Clostridioides difficile isolated from patient diarrhea samples from Hamadan Hospitals, west of Iran.

Background

The concentration of C. difficile toxins (CDTs) is associated with the severity of the disease and the mortality rate. Measuring CDT levels could provide a reliable and objective means of determining the severity of C. difficile infection (CDI).

Methods

From November 2018 to September 2019, 130 diarrhea samples were collected from hospitalized patients in three hospitals in Hamadan. C. difficle isolates were detected by culture and PCR. The presence of the genes encoding the toxin was identified by PCR, whereas the measurement of toxin expression was conducted using a relative Real-Time PCR technique. Genetic linkage of the isolates was also assessed by Ribotyping and Repetitive Extragenic Palindromic (rep-PCR) methods.

Results

Among 130 diarrhea samples, 16 (12.3%) were positive for C. difficile. Genes encoding cdtA and tcdB were detected in all isolates, and 8 (50%) and 6 (37.5%) isolates were positive for the cdtA and cdtB genes. Real-time PCR results showed different expression levels of the toxin genes. A significant increase in the expression of the tcdA gene was observed compared with the control strain (P<0.05). Besides, more expression of cdtA gene was observed in the strains compared with cdtB gene. Ribotyping and rep-PCR results showed high genetic diversity of C. difficile among hospitals investigated.

Conclusion

We encountered toxigenic C. difficile strains with various toxin expression levels, ribotypes, and rep types based on the findings of this study. This indicated that various clones from various sources circulate in the hospitals and among patients.

Clostridioides difficile PCR ribotypes 001 and 084 can trigger autophagy process in human intestinal Caco-2 cells

Autophagy is a homeostatic process that can promote cell survival or death. However, the exact role of autophagy in Clostridioides difficile infection (CDI) is still not precisely elucidated. Here, we investigate the role of distinct C. difficile ribotypes (RTs) in autophagy induction using Caco-2 cells. The expression analysis of autophagy-associated genes and related miRNAs were examined following treatment of Caco-2 cells with C. difficile after 4 and 8 h using RT-qPCR. Toxin production was assessed using enzyme-linked immunosorbent assay (ELISA). Immunofluorescence analysis was performed to detect MAP1LC3B/LC3B, followed by an autophagic flux analysis. C. difficile significantly reduced the viability of Caco-2 cells in comparison with untreated cells. Elevated levels of LC3-II and SQSTM1/p62 by C. difficile RT001 and RT084 in the presence of E64d/leupeptin confirmed the induction of autophagy activity. Similarly, the immunofluorescence analysis demonstrated that C. difficile RT001 and RT084 significantly increased the amount of LC3-positive structures in Caco-2 cells. The induction of autophagy was further demonstrated by increased levels of LC3B, ULK1, ATG12, PIK3C3/VPS34, BECN1 (beclin 1), ATG5, and ATG16L1 transcripts and reduced levels of AKT and MTOR gene expression. The expression levels of MIR21 and MIR30B, microRNAs that suppress autophagy, were differentially affected by C. difficile. In conclusion, the present work revealed that C. difficile bacteria can induce autophagy through both toxin-dependent and -independent mechanisms. Also, our results suggest the potential role of other C. difficile virulence factors in autophagy modulation using intestinal cells in vitro.

Pleiotropic effects of Mentha longifolia L. extract on the regulation of genes involved in inflammation and apoptosis induced by Clostridioides difficile ribotype 001

Introduction

The dramatic increase in multidrug-resistance of Clostridioides difficile isolates has led to the search for new complementary medicines against C. difficile infection (CDI). In this study, we aimed to examine the inhibitory effects of hydroethanolic extract of Mentha longifolia L. (ETOH-ML) on the growth of C. difficile RT001 and its toxigenic cell-free supernatant (Tox-S)-induced inflammation and apoptosis.

Methods

The active phytochemical components of ETOH-ML were detected using GC and HPLC. The antimicrobial properties of the extract were examined against C. difficile RT001. Furthermore, cell viability and cytotoxicity of Caco-2 and Vero cells treated with various concentrations of ETOH-ML, Tox-S of C. difficile RT001, and their combination were assessed. Anti-inflammatory and anti-apoptotic activities of ETOH-ML were explored in Tox-S stimulated Caco-2 cells using RT-qPCR.

Results

Based on our results, rosmarinic acid was the main phytochemical component of ETOH-ML. The extract showed significant antimicrobial activity against C. difficile RT001 by agar dilution and broth microdilution methods. Moreover, ETOH-ML at concentrations of <25 μg/ml had no significant effect on cell viability compared to untreated cells. Treatment cells with the extract (10 or 25 μg/ml) significantly increased the cell viability and reduced the percentage of cell rounding in Caco-2 and Vero cells treated by Tox-S, respectively (P < 0.0001). Co-treatment of Tox-S stimulated Caco-2 cells with ETOH-ML showed significant anti-inflammatory and anti-apoptotic activities by downregulating the gene expression level of IL-8, IL-1β, TNF-α, iNOS, TGF-β, NF-κB, Bax, and caspase-3, while upregulating the expression level of Bcl-2.

Discussion

Our results demonstrated for the first time the antimicrobial, anti-inflammatory, and anti-apoptotic effects of M. longifolia extract on C. difficile RT001 and its Tox-S. However, further research is needed to evaluate the potential application of M. longifolia extract on CDI treatment in clinical setting.

Development and characterization of phage display-derived anti-toxin antibodies neutralizing TcdA and TcdB of Clostridioides difficile

TcdA and TcdB are known as the major virulence attributes of Clostridioides difficile. Hence, neutralizing the TcdA and TcdB activities can be considered as an efficient therapeutic approach against C. difficile infection (CDI). In this work, we utilized phage display technique to select single-chain fragment variable (scFv) fragments as recombinant antibodies displayed on the surface of phages, which specifically target native TcdA, or TcdB (nTcdA and nTcdB), and their recombinant C-terminal combined repetitive oligopeptide (CROP) domains (rTcdA and rTcdB). After three rounds of biopanning, abundance of phage clones displaying high reactivity with TcdA or TcdB was quantified through enzyme-linked immunosorbent assay (ELISA). Furthermore, selected scFvs were characterized by cell viability and neutralization assays. The gene expression of immunological markers, IL-8 and TNF-α, was examined in treated Caco-2 cells by RT-qPCR. The epitopes of neutralizing scFvs were also identified by molecular docking. Totally, 18 scFv antibodies (seven for TcdA and 11 for TcdB) were identified by ELISA. Among selected scFvs, two clones for TcdA (rA-C2, A-C9) and three clones for TcdB (rB-B4, B-F5, B-F11) exhibited the highest neutralizing activity in Caco-2 and Vero cells. Moreover, the cocktail of anti-TcdA and anti-TcdB antibodies notably decreased the mRNA expression of TNF-α and IL-8 in Caco-2 cells. Molecular docking revealed that the interaction between scFv and toxin was mostly restricted to CROP domain of TcdA or TcdB. Our results collectively provided more insights for the development of neutralizing scFvs against C. difficile toxins using phage display. Further research is needed to meticulously evaluate the potential of scFvs as an alternative treatment for CDI using animal models and clinical trials.IMPORTANCETargeting the major toxins of Clostridioides difficile by neutralizing antibodies is a novel therapeutic approach for CDI. Here, we report a panel of new anti-TcdA (rA-C2, A-C9) and anti-TcdB (rB-B4, B-F5, and B-F11) recombinant antibody fragments (scFvs) isolated from Tomlinson I and J libraries using phage display technique. These scFv antibodies were capable of neutralizing their respective toxin and showed promise as potential therapeutics against TcdA and TcdB of C. difficile in different in vitro models. In addition, in silico analysis showed that at least two neutralization mechanisms, including inhibiting cell surface binding of toxins and inhibiting toxin internalization can be proposed for the isolated scFvs in this work. These findings provide more insights for the applicability of specific scFvs toward C. difficile toxins at in vitro level. However, further research is required to evaluate the potential application of these scFvs as therapeutic agents for CDI treatment in clinical setting.

Insights into the Evolving Epidemiology of Clostridioides difficile Infection and Treatment: A Global Perspective

Clostridioides difficile remains an important public health threat, globally. Since the emergence of the hypervirulent strain, ribotype 027, new strains have been reported to cause C. difficile infection (CDI) with poor health outcomes, including ribotypes 014/020, 017, 056, 106, and 078/126. These strains differ in their geographic distribution, genetic makeup, virulence factors, and antimicrobial susceptibility profiles, which can affect their ability to cause disease and respond to treatment. As such, understanding C. difficile epidemiology is increasingly important to allow for effective prevention measures. Despite the heightened epidemiological surveillance of C. difficile over the past two decades, it remains challenging to accurately estimate the burden and international epidemiological trends given the lack of concerted global effort for surveillance, especially in low- and middle-income countries. This review summarizes the changing epidemiology of C. difficile based on available data within the last decade, highlights the pertinent ribotypes from a global perspective, and discusses evolving treatments for CDI.

The Environment, Farm Animals and Foods as Sources of Clostridioides difficile Infection in Humans

The recent discovery of the same Clostridioides difficile ribotypes associated with human infection in a broad range of environments, animals and foods, coupled with an ever-increasing rate of community-acquired infections, suggests this pathogen may be foodborne. The objective of this review was to examine the evidence supporting this hypothesis. A review of the literature found that forty-three different ribotypes, including six hypervirulent strains, have been detected in meat and vegetable food products, all of which carry the genes encoding pathogenesis. Of these, nine ribotypes (002, 003, 012, 014, 027, 029, 070, 078 and 126) have been isolated from patients with confirmed community-associated C. difficile infection (CDI). A meta-analysis of this data suggested there is a higher risk of exposure to all ribotypes when consuming shellfish or pork, with the latter being the main foodborne route for ribotypes 027 and 078, the hypervirulent strains that cause most human illnesses. Managing the risk of foodborne CDI is difficult as there are multiple routes of transmission from the farming and processing environment to humans. Moreover, the endospores are resistant to most physical and chemical treatments. The most effective current strategy is, therefore, to limit the use of broad-spectrum antibiotics while advising potentially vulnerable patients to avoid high-risk foods such as shellfish and pork.

Novel ribotype/sequence type associations and diverse CRISPR-Cas systems in environmental Clostridioides difficile strains from northern Iraq

The environment is a natural reservoir of Clostridioides difficile, and here, we aimed to isolate the pathogen from seven locations in northern Iraq. Four of the sites yielded thirty-one isolates (ten from soils, twenty-one from sediments), which together represent ribotypes (RTs) 001 (five), 010 (five), 011 (two), 035 (two), 091 (eight), and 604 (nine). Twenty-five of the isolates (∼81%) are non-toxigenic, while six (∼19%) encode the toxin A and B genes. The genomes of eleven selected isolates represent six sequence types (STs): ST-3 (two), ST-15 (one), ST-107 (five), ST-137 (one), ST-177 (one), and ST-181 (one). Five novel RT/ST associations: RT011/ST-137, RT035/ST-107, RT091/ST-107, RT604/ST-177, and RT604/ST-181 were identified, and the first three are linked to RTs previously uncharacterized by multilocus sequence typing (MLST). Nine of the genomes belong to Clade 1, and two are closely related to the cryptic C-I clade. Diverse multiple prophages and CRISPR-Cas systems (class 1 subtype I-B1 and class 2 type V CRISPR-Cas systems) with spacers identical to other C. difficile phages and plasmids were detected in the genomes. Our data show the broader diversity that exists within environmental C. difficile strains from a much less studied location and their potential role in the evolution and emergence of new strains.

Rapid-format recombinant antibody-based methods for the diagnosis of Clostridioides difficile infection: Recent advances and perspectives

Clostridioides difficile, the most common cause of nosocomial diarrhea, has been continuously reported as a worldwide problem in healthcare settings. Additionally, the emergence of hypervirulent strains of C. difficile has always been a critical concern and led to continuous efforts to develop more accurate diagnostic methods for detection of this recalcitrant pathogen. Currently, the diagnosis of C. difficile infection (CDI) is based on clinical manifestations and laboratory tests for detecting the bacterium and/or its toxins, which exhibit varied sensitivity and specificity. In this regard, development of rapid diagnostic techniques based on antibodies has demonstrated promising results in both research and clinical environments. Recently, application of recombinant antibody (rAb) technologies like phage display has provided a faster and more cost-effective approach for antibody production. The application of rAbs for developing ultrasensitive diagnostic tools ranging from immunoassays to immunosensors, has allowed the researchers to introduce new platforms with high sensitivity and specificity. Additionally, DNA encoding antibodies are directly accessible in these approaches, which enables the application of antibody engineering to increase their sensitivity and specificity. Here, we review the latest studies about the antibody-based ultrasensitive diagnostic platforms for detection of C. difficile bacteria, with an emphasis on rAb technologies.

Detection and Genomic Characterisation of Clostridioides difficile from Spinach Fields

Despite an increased incidence of Clostridioides difficile infections, data on the reservoirs and dissemination routes of this bacterium are limited. This study examined the prevalence and characteristics of C. difficile isolates in spinach fields. C. difficile was detected in 2/60 (3.3%) of spinach and 6/60 (10%) of soil samples using culture-based techniques. Whole genome sequencing (WGS) analysis identified the spinach isolates as belonging to the hypervirulent clade 5, sequence type (ST) 11, ribotypes (RT) 078 and 126 and carried the genes encoding toxins A, B and CDT. The soil isolates belonged to clade 1 with different toxigenic ST/RT (ST19/RT614, ST12/RT003, ST46/RT087, ST16/RT050, ST49/RT014/0) strains and one non-toxigenic ST79/RT511 strain. Antimicrobial resistance to erythromycin (one spinach isolate), rifampicin (two soil isolates), clindamycin (one soil isolate), both moxifloxacin and rifampicin (one soil isolate), and multi-drug resistance to erythromycin, vancomycin and rifampicin (two soil isolates) were observed using the E test, although a broader range of resistance genes were detected using WGS. Although the sample size was limited, our results demonstrate the presence of C. difficile in horticulture and provide further evidence that there are multiple sources and dissemination routes for these bacteria.

Surface layer protein A from hypervirulent Clostridioides difficile ribotypes induce significant changes in the gene expression of tight junctions and inflammatory response in human intestinal epithelial cells

Background

Surface layer protein A (SlpA), the primary outermost structure of Clostridioides difficile, plays an essential role in C. difficile pathogenesis, although its interaction with host intestinal cells are yet to be understood. The aim of this study was to investigate the effects of SlpA extracted from C. difficile on tight junction (TJ) proteins expression and induction of pro-inflammatory cytokines in human colon carcinoma cell line HT-29. SlpA was extracted from three toxigenic C. difficile clinical strains including RT126, RT001, RT084 as well as C. difficile ATCC 700057 as non-toxigenic strain. Cell viability was performed by MTT assay, and the mRNA expression of TJ proteins and inflammation-associated genes was determined using quantitative RT-PCR. Additionally, the secretion of IL-8, IL-1β and TNF-α cytokines was measured by ELISA.

Results

C. difficile SlpA from selected RTs variably downregulated the expression level of TJs-assassinated genes and increased the expression level of TLR-4 and pro-inflammatory cytokines in HT-29 treated cells. SlpA from RT126 significantly (p_adj<0.05) decreased the gene expression level of claudins family and JAM-A and increased the secretion of IL-8, TNF-α and IL1-β as compared to untreated cells. Moreover, only SlpA from RT001 could significantly induce the expression of IL-6 (p_adj<0.05).

Conclusion

The results of the present study highlighted the importance of SlpA in the pathogenesis of CDI and C. difficile-induced inflammatory response in the gut. Further studies are required to unravel the significance of the observed results in promoting the intestinal inflammation and immune response induced by C. difficile SlpA from different RTs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02665-0.

High Prevalence Rate of Microbial Contamination in Patient-Ready Gastrointestinal Endoscopes in Tehran, Iran: an Alarming Sign for the Occurrence of Severe Outbreaks

An alarmingly increasing number of outbreaks caused by contaminated gastrointestinal (GI) endoscopes are being reported as a particularly concerning issue. This study is the first large-scale multicenter survey to evaluate the contamination of GI endoscopes in Tehran, Iran. This multicenter study was conducted among 15 tertiary referral and specialized gastrointestinal settings. Reprocessed GI endoscopes were sampled by the sequence of the flush-brush-flush method. Bacterial and viral contamination, as well as antimicrobial resistance, were explored by culture and molecular assays. A total of 133 reprocessed and ready-to-use GI endoscopes were investigated. In phase I and phase II, 47% and 32%, respectively, of the GI endoscopes were determined to be contaminated. GI flora was the most prevalent contaminant isolated from GI endoscopes, in which the most predominant bacteria were Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae, in both phase I and II evaluations. The majority of the isolated bacteria in the current study were considered multidrug-resistant organisms (MDROs). More importantly, we recovered carbapenem-resistant nonfermentative Gram-negative bacilli (CRNFGNB), carbapenem-resistant Enterobacterales (CRE), extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E), multidrug-resistant Clostridioides difficile, vancomycin-resistant Enterococcus (VRE), and drug-resistant Candida spp. Disconcertingly, our molecular assays revealed contamination of some reprocessed GI endoscopes with hepatitis B virus (HBV), hepatitis C virus (HCV), and even HIV. This multicenter study indicates a higher-than-expected contamination rate among reprocessed and ready-for-patient-use GI endoscopes, which suggests a higher-than-expected endoscopy-associated infection (EAI) risk, and potentially, morbidity and mortality rate, associated with endoscopy procedures in Tehran, Iran. IMPORTANCE In the light of severe outbreaks caused by multidrug-resistant microorganisms due to contaminated GI endoscopes, understanding to what extent GI endoscopes are inadequately reprocessed is crucial. Several studies assessed contamination of GI endoscopes with various outcomes across the world; however, the prevalence and risk factors of contaminated GI endoscopes and potential subsequent nosocomial spread are still unknown in Iran. The present study is the first large-scale multicenter survey to evaluate the microbial contamination of repossessed and ready-to-use GI endoscopes in Tehran, Iran. Our study showed a higher-than-expected contamination rate among reprocessed GI endoscopes, which suggests potential seeding of deadly but preventable outbreaks associated with endoscopy procedures in Iran. These results suggest that the current reprocessing and process control guidelines do not suffice in Iran. The current study is of particular importance and could provide insights into unrecognized and unidentified endoscopy-associated outbreaks in Iran.

Curcumin and capsaicin regulate apoptosis and alleviate intestinal inflammation induced by Clostridioides difficile in vitro

Background

The dramatic upsurge of Clostridioides difficile infection (CDI) by hypervirulent isolates along with the paucity of effective conventional treatment call for the development of new alternative medicines against CDI. The inhibitory effects of curcumin (CCM) and capsaicin (CAP) were investigated on the activity of toxigenic cell-free supernatants (Tox-S) of C. difficile RT 001, RT 126 and RT 084, and culture-filtrate of C. difficile ATCC 700057.

Methods

Cell viability of HT-29 cells exposed to varying concentrations of CCM, CAP, C. difficile Tox-S and culture-filtrate was assessed by MTT assay. Anti-inflammatory and anti-apoptotic effects of CCM and CAP were examined by treatment of HT-29 cells with C. difficile Tox-S and culture-filtrate. Expression of BCL-2, SMAD3, NF-κB, TGF-β and TNF-α genes in stimulated HT-29 cells was measured using RT-qPCR.

Results

C. difficile Tox-S significantly (P < 0.05) reduced the cell viability of HT-29 cells in comparison with untreated cells. Both CAP and CCM significantly (P < 0.05) downregulated the gene expression level of BCL-2, SMAD3, NF-κB and TNF-α in Tox-S treated HT-29 cells. Moreover, the gene expression of TGF-β decreased in Tox-S stimulated HT-29 cells by both CAP and CCM, although these reductions were not significantly different (P > 0.05).

Conclusion

The results of the present study highlighted that CCM and CAP can modulate the inflammatory response and apoptotic effects induced by Tox-S from different clinical C. difficile strains in vitro. Further studies are required to accurately explore the anti-toxin activity of natural components, and their probable adverse risks in clinical practice.

Application of recombinant antibodies for treatment of Clostridioides difficile infection: Current status and future perspective

Clostridioides difficile (C. difficile), known as the major cause of antibiotic-associated diarrhea, is regarded as one of the most common healthcare-associated bacterial infections worldwide. Due to the emergence of hypervirulent strains, development of new therapeutic methods for C. difficile infection (CDI) has become crucially important. In this context, antibodies have been introduced as valuable tools in the research and clinical environments, as far as the effectiveness of antibody therapy for CDI was reported in several clinical investigations. Hence, production of high-performance antibodies for treatment of CDI would be precious. Traditional approaches of antibody generation are based on hybridoma technology. Today, application of in vitro technologies for generating recombinant antibodies, like phage display, is considered as an appropriate alternative to hybridoma technology. These techniques can circumvent the limitations of the immune system and they can be exploited for production of antibodies against different types of biomolecules in particular active toxins. Additionally, DNA encoding antibodies is directly accessible in in vitro technologies, which enables the application of antibody engineering in order to increase their sensitivity and specificity. Here, we review the application of antibodies for CDI treatment with an emphasis on recombinant fragment antibodies. Also, this review highlights the current and future prospects of the aforementioned approaches for antibody-mediated therapy of CDI.

The double-edged sword of probiotic supplementation on gut microbiota structure in Helicobacter pylori management

As Helicobacter pylori management has become more challenging and less efficient over the last decade, the interest in innovative interventions is growing by the day. Probiotic co-supplementation to antibiotic therapies is reported in several studies, presenting a moderate reduction in drug-related side effects and a promotion in positive treatment outcomes. However, the significance of gut microbiota involvement in the competence of probiotic co-supplementation is emphasized by a few researchers, indicating the alteration in the host gastrointestinal microbiota following probiotic and drug uptake. Due to the lack of long-term follow-up studies to determine the efficiency of probiotic intervention in H. pylori eradication, and the delicate interaction of the gut microbiota with the host wellness, this review aims to discuss the gut microbiota alteration by probiotic co-supplementation in H. pylori management to predict the comprehensive effectiveness of probiotic oral administration.Abbreviations: acyl-CoA- acyl-coenzyme A; AMP- antimicrobial peptide; AMPK- AMP-activated protein kinase; AP-1- activator protein 1; BA- bile acid; BAR- bile acid receptor; BCAA- branched-chain amino acid; C2- acetate; C3- propionate; C4- butyrate; C5- valeric acid; CagA- Cytotoxin-associated gene A; cAMP- cyclic adenosine monophosphate; CD- Crohn's disease; CDI- C. difficile infection; COX-2- cyclooxygenase-2; DC- dendritic cell; EMT- epithelial-mesenchymal transition; FMO- flavin monooxygenases; FXR- farnesoid X receptor; GPBAR1- G-protein-coupled bile acid receptor 1; GPR4- G protein-coupled receptor 4; H2O2- hydrogen peroxide; HCC- hepatocellular carcinoma; HSC- hepatic stellate cell; IBD- inflammatory bowel disease; IBS- irritable bowel syndrome; IFN-γ- interferon-gamma; IgA immunoglobulin A; IL- interleukin; iNOS- induced nitric oxide synthase; JAK1- janus kinase 1; JAM-A- junctional adhesion molecule A; LAB- lactic acid bacteria; LPS- lipopolysaccharide; MALT- mucosa-associated lymphoid tissue; MAMP- microbe-associated molecular pattern; MCP-1- monocyte chemoattractant protein-1; MDR- multiple drug resistance; mTOR- mammalian target of rapamycin; MUC- mucin; NAFLD- nonalcoholic fatty liver disease; NF-κB- nuclear factor kappa B; NK- natural killer; NLRP3- NLR family pyrin domain containing 3; NOC- N-nitroso compounds; NOD- nucleotide-binding oligomerization domain; PICRUSt- phylogenetic investigation of communities by reconstruction of unobserved states; PRR- pattern recognition receptor; RA- retinoic acid; RNS- reactive nitrogen species; ROS- reactive oxygen species; rRNA- ribosomal RNA; SCFA- short-chain fatty acids; SDR- single drug resistance; SIgA- secretory immunoglobulin A; STAT3- signal transducer and activator of transcription 3; T1D- type 1 diabetes; T2D- type 2 diabetes; Th17- T helper 17; TLR- toll-like receptor; TMAO- trimethylamine N-oxide; TML- trimethyllysine; TNF-α- tumor necrosis factor-alpha; Tr1- type 1 regulatory T cell; Treg- regulatory T cell; UC- ulcerative colitis; VacA- Vacuolating toxin A.

Clostridioides difficile epidemiology in the Middle and the Far East

OBJECTIVES

Clostridioides difficile is an important pathogen of healthcare-associated gastrointestinal infections. Recently, an increased number of C. difficile infection (CDI) surveillance data has been reported from Asia. The aim of this review is to summarize the data on the prevalence, distribution and molecular epidemiology of CDI in the Middle and the Far East.

METHODS

Literature was drawn from a search of PubMed up to September 30, 2021.

RESULTS

The meta-analysis of data from 111 studies revealed the pooled CDI prevalence rate in the Middle and the Far East of 12.4% (95% CI 11.4-13.3); 48 studies used PCR for CDI laboratory diagnoses. The predominant types (RT)/sequence type (ST) differ between individual countries (24 studies, 14 countries). Frequently found RTs were 001, 002, 012, 017, 018 and 126; RT017 was predominant in the Far East. The epidemic RT027 was detected in 8 countries (22 studies), but its predominance was reported only in three studies (Israel and Iran). The contamination of vegetable and meat or meat products and/or intestinal carriage of C. difficile in food and companion animals have been reported; the C. difficile RTs/STs identified overlapped with those identified in humans.

CONCLUSIONS

A large number of studies on CDI prevalence in humans from the Middle and the Far East have been published; countries with no available data were identified. The number of studies on C. difficile from non-human sources is limited. Comparative genomic studies of isolates from different sources are needed.

Alterations and Prediction of Functional Profiles of Gut Microbiota After Fecal Microbiota Transplantation for Iranian Recurrent Clostridioides difficile Infection with Underlying Inflammatory Bowel Disease: A Pilot Study

BACKGROUND AND PURPOSE

Fecal microbiota transplantation (FMT) has emerged for the therapeutic treatment of recurrent Clostridioides difficile infection (rCDI) with concurrent inflammatory bowel disease (IBD). As the first Iranian population cohort, we examined how gut microbiota and their functional profiles change in Iranian rCDI patients with underlying IBD before and after FMT.

PATIENTS AND METHODS

FMT was performed to eight IBD patients via colonoscopy. Profiles of gut microbiota from donors and recipients were investigated using 16S rRNA gene sequence analysis.

RESULTS

Patients experienced no IBD flare-ups or other adverse effects, and all recovered to full health. Moreover, all rCDI patients lacked the Bacteroidetes present in donor samples. After FMT, the proportion of Bacteroidetes increased until a normal range was achieved. More specifically, the relative abundance of Prevotella was found to increase significantly following FMT. Prevotella was also found to correlate negatively with inflammation metrics, suggesting that Prevotella may be a key factor for resolving CDI and IBD. Gut microbiota diversity was found to increase following FMT, while dysbiosis decreased. However, the similarity of microbial communities of host and recipients did not increase, and wide variation in the extent of donor stool engraftment indicated that the gut bacterial communities of recipients do not shift towards those of donors.

CONCLUSION

FMT leads to significant alterations of the community structure of gut bacteria in rCDI patients with IBD. The change in relative abundance of Proteobacteria and bacterial diversity indicated that FMT promotes recovery from intestinal permeability and inflammation in rCDI patients. Moreover, strong negative correlation between Prevotella and inflammation index, and decreased dysbiosis index advocate that the improvement of CDI is possibly due to gut microbiome alteration. Collectively, our findings show that FMT would be a promising therapy to help reprogram the gut microbiome of Iranian rCDI patients with IBD.

How Does COVID-19 Pandemic Impact on Incidence of Clostridioides difficile Infection and Exacerbation of Its Gastrointestinal Symptoms?

Coronavirus disease 2019 (COVID-19) has rapidly spread all over the world with a very high rate of mortality. Different symptoms developed by COVID-19 infection and its impacts on various organs of the human body have highlighted the importance of both coinfections and superinfections with other pathogens. The gastrointestinal (GI) tract is vulnerable to infection with COVID-19 and can be exploited as an alternative transmission route and target for virus entry and pathogenesis. The GI manifestations of COVID-19 disease are associated with severe disease outcomes and death in all age groups, in particular, elderly patients. Empiric antibiotic treatments for microbial infections in hospitalized patients with COVID-19 in addition to experimental antiviral and immunomodulatory drugs may increase the risk of antibiotic-associated diarrhea (AAD) and Clostridioides difficile infection (CDI). Alterations of gut microbiota are associated with depletion of beneficial commensals and enrichment of opportunistic pathogens such as C. difficile. Hence, the main purpose of this review is to explain the likely risk factors contributing to higher incidence of CDI in patients with COVID-19. In addition to lung involvement, common symptoms observed in COVID-19 and CDI such as diarrhea, highlight the significance of bacterial infections in COVID-19 patients. In particular, hospitalized elderly patients who are receiving antibiotics might be more prone to CDI. Indeed, widespread use of broad-spectrum antibiotics such as clindamycin, cephalosporins, penicillin, and fluoroquinolones can affect the composition and function of the gut microbiota of patients with COVID-19, leading to reduced colonization resistance capacity against opportunistic pathogens such as C. difficile, and subsequently develop CDI. Moreover, patients with CDI possibly may have facilitated the persistence of SARS-CoV-2 viral particles in their feces for approximately one month, even though the nasopharyngeal test turned negative. This coinfection may increase the potential transmissibility of both SARS-CoV-2 and C. difficile by fecal materials. Also, CDI can complicate the outcome of COVID-19 patients, especially in the presence of comorbidities or for those patients with prior exposure to the healthcare setting. Finally, physicians should remain vigilant for possible SARS-CoV-2 and CDI coinfection during the ongoing COVID-19 pandemic and the excessive use of antimicrobials and biocides.

Serum procalcitonin levels associate with Clostridioides difficile infection in patients with inflammatory bowel disease

BACKGROUND

Clostridioides difficile infection (CDI) is a major cause of morbidity among patients with inflammatory bowel disease (IBD). Diagnostic biomarkers for early detection of CDI are needed in clinical practice. The relationship between serum procalcitonin and CDI in IBD patients has not been investigated so far. Therefore, we aimed to evaluate the usefulness of measuring serum procalcitonin level to detect CDI in patients with the flare of IBD.

METHODS

One hundred twenty patients with IBD were enrolled in this study. Bacterial identification was performed using standard microbiological and molecular methods. The serum procalcitonin levels were measured in all patients. Receiver operating characteristic (ROC) curve analysis was applied to assess the value of procalcitonin for the prediction of CDI among IBD patients.

RESULTS

The median serum procalcitonin level was significantly increased in IBD patients with CDI compared to non-CDI IBD patients (0.69 ng/mL vs 0.32 ng/mL). In univariate analysis, log₁₀ procalcitonin was associated with CDI (OR 2.81, 95% CI 1.54-4.09, P-value < 0.001). Procalcitonin 1.1 ng/mL was 85% sensitive and 88% specific for the prediction of CDI. In the multivariable model including the covariates log₁₀ procalcitonin, age, hospitalization, type of IBD, duration of the disease, and antibiotic usage, procalcitonin showed a robust association with CDI (OR 4.59, 95% CI 2.49-6.70, P-value < 0.001). An elevated procalcitonin level was associated with the presence of CDI among IBD patients.

CONCLUSIONS

Our results indicate that procalcitonin level can be a good candidate biomarker for assessing the CDI in IBD patients. Further studies are required to decipher whether procalcitonin can predict CDI therapy or its recurrence.

Characteristics of patients infected with Clostridioides difficile at a Saudi Tertiary Academic Medical Center and assessment of antibiotic duration

BACKGROUND

Clostridioides difficile infection (CDI) is a common hospital-associated diarrhea. Several antibiotics commonly associate with CDI; however, limited data are available on the duration of exposure prior to CDI. Moreover, studies on the characteristics of CDI patients in Saudi Arabia are limited. Therefore, this study aimed to characterize CDI patients identified over 10 years and assess antibiotic days of therapy (DOT) prior to CDI.

METHODS

This was a retrospective descriptive analysis of CDI patients at a Saudi tertiary academic medical center between December 2007 and January 2018. Patients characteristics, prior exposure to known CDI risk factors, and DOT of antibiotics prior to CDI incidence were assessed.

RESULTS

A total of 159 patients were included. Median age was 62 years. Most cases were hospital-acquired (71.1%), non-severe (44.7%), and admitted to medical wards (81.1%). Prior exposure to antibiotics and acid suppression therapy were reported with the majority (76.1 and 75.5%, respectively). The most frequently prescribed antibiotics were piperacillin/tazobactam, ceftriaxone, meropenem, and ciprofloxacin with median DOTs prior to CDI incidence of 14 days for the β-lactams and 26 days for ciprofloxacin. The distribution of DOT was significantly different for piperacillin/tazobactam in different units (P = 0.003) where its median DOT was the shortest in medical wards (11 days), and for ciprofloxacin among different severity groups (P = 0.013), where its median DOT was the shortest in severe CDI patients (11 days).

CONCLUSION

Most patients in this study had hospital-acquired non-severe CDI and were largely exposed to antibiotics and acid suppression therapy. Therefore, such therapies should be revised for necessity.

Frequency of toxin genes and antibiotic resistance pattern of Clostridioides difficile isolates in diarrheal samples among hospitalized patients in Hamadan, Iran

AIM

This study was designed to investigate the prevalence of Clostridioides difficile, its toxin-producing genes, and antibiotic resistance patterns in diarrheal samples from hospitalized patients in Hamadan, Iran.

BACKGROUND

Today, concerns over Clostridioides difficile infection (CDI) have significantly increased due to reduced susceptibility to antibiotics used for CDI treatment. Toxins produced by C. difficile strains are associated with disease severity and outcome.

METHODS

In this cross-sectional study, a total of 130 diarrheal samples of patients admitted to different wards of three hospitals in Hamadan from November 2018 to September 2019 were collected. C. difficile isolates were identified by culture on CCFA and PCR (Polymerase chain reaction). The presence of toxin-encoding genes (tcdA and tcdB) and binary toxin genes (cdtA and cdtB) was analyzed by PCR. Resistance of the isolates to metronidazole, vancomycin and clindamycin antibiotics was determined using agar dilution method.

RESULTS

Out of 130 diarrheal samples from hospitalized patients, 16 (12.3%) C. difficile isolates were obtained. PCR results were positive for two toxin-producing genes, tcdA and tcdB, in all (100%) C. difficile isolates, and the binary toxin genes cdtA and cdtB were detected in 6 (37.5%) and 8 (50%) isolates, respectively. The results of antibiotic susceptibility testing showed resistance to metronidazole, vancomycin, and clindamycin in 3 (18.7%), 3 (18.7%), and 2 (12.5%) isolates, respectively, and all isolates were resistant to rifampicin.

CONCLUSION

The results of this study showed toxigenic C. difficile with tcdA ⁺ /tcdB ⁺ profile is a major cause of nosocomial diarrhea in Hamadan, and clinical laboratories should routinely perform C. difficile diagnostic testing on diarrheal specimens of hospitalized patients. Resistance to conventional antibiotic therapy against C. difficile should be considered as a warning to prevent irrational administration of antibiotics.

Treatment of Recurrent Clostridioides difficile Infection Using Fecal Microbiota Transplantation in Iranian Patients with Underlying Inflammatory Bowel Disease

PURPOSE

Fecal microbiota transplantation (FMT) is an effective treatment option for patients with recurrent Clostridioides difficile infection (rCDI). However, there is a paucity of evidence regarding its efficacy and safety in patients with rCDI and concurrent inflammatory bowel disease (IBD). Here, we present a single-center experience of FMT for treatment of rCDI in Iranian patients with IBD.

PATIENTS AND METHODS

Eight patients with established IBD (7 with ulcerative colitis and 1 with Crohn's disease) who underwent at least one FMT via colonoscopy for treatment of rCDI were enrolled in this study. Demographics, pre-FMT and post-FMT IBD activity, efficacy for rCDI and adverse events (AEs) were assessed during a 6-month follow-up period. All patients had experienced 3 episodes of rCDI and were refractory to conventional therapies with metronidazole and vancomycin. Primary cure and secondary cure rates were assessed after FMT treatments.

RESULTS

A total of 10 FMTs were performed via colonoscopy in 8 patients (6/8; 75% men) with a median age of 35 years (range: 22-60). Two patients received a second FMT. Overall, the primary and secondary cure rates were 75% and 100%, respectively. Two patients developed CPE-producing C. perfringens diagnoses after second FMTs. There were no other AEs, and no patient experienced IBD flare.

CONCLUSION

We demonstrated that FMT appears to be an effective, safe and rational therapeutic alternative for resolution of rCDI in patients with underlying IBD. Furthermore, we suggest implementing the CPE-producing C. perfringens testing in the screening of FMT donors.