Identifying patients at risk of severe Clostridium difficile-associated disease

A new score to predict Clostridioides difficile infection in medical patients: a sub-analysis of the FADOI-PRACTICE study

Medical divisions are at high risk of Clostridioides difficile infection (CDI) due to patients' frailty and complexity. This sub-analysis of the FADOI-PRACTICE study included patients presenting with diarrhea either at admission or during hospitalization. CDI diagnosis was confirmed when both enzyme immunoassay and A and B toxin detection were found positive. The aim of this sub-analysis was the identification of a new score to predict CDI in hospitalized, medical patients. Five hundred and seventy-two patients with diarrhea were considered. More than half of patients was female, 40% on antibiotics in the previous 4 weeks and 60% on proton pump inhibitors (PPIs). CDI diagnosis occurred in 103 patients (18%). Patients diagnosed with CDI were older, more frequently of female sex, recently hospitalized and bed-ridden, and treated with antibiotics and PPIs. Through a backward stepwise logistic regression model, age > 65 years, female sex, recent hospitalization, recent antibiotic therapy, active cancer, prolonged hospital stay (> 12 days), hypoalbuminemia (albumin < 3 g/dL), and leukocytosis (white blood cells > 9 × 10^9/L) were found to independently predict CDI occurrence. These variables contributed to building a clinical prognostic score with a good sensitivity and a modest specificity for a value > 3 (79% and 58%, respectively; AUC 0.75, 95% CI 0.71-0.79, p < 0.001), that identified low-risk (score ≤ 3; 42.5%) and high-risk (score > 3; 57.5%) patients. Although some classical risk factors were confirmed to increase CDI occurrence, the changing landscape of CDI epidemiology suggests a reappraisal of common risk factors and the development of novel risk scores based on local epidemiology.

Sexual dimorphism in bacterial infections

Background

Sex differences are important epidemiological factors that impact in the frequency and severity of infectious diseases. A clear sexual dimorphism in bacterial infections has been reported in both humans and animal models. Nevertheless, the molecular mechanisms involved in this gender bias are just starting to be elucidated. In the present article, we aim to review the available data in the literature that report bacterial infections presenting a clear sexual dimorphism, without considering behavioral and social factors.

Main body

The sexual dimorphism in bacterial infections has been mainly attributed to the differential levels of sex hormones between males and females, as well as to genetic factors. In general, males are more susceptible to gastrointestinal and respiratory bacterial diseases and sepsis, while females are more susceptible to genitourinary tract bacterial infections. However, these incidences depend on the population evaluated, animal model and the bacterial species. Female protection against bacterial infections and the associated complications is assumed to be due to the pro-inflammatory effect of estradiol, while male susceptibility to those infections is associated with the testosterone-mediated immune suppression, probably via their specific receptors. Recent studies indicate that the protective effect of estradiol depends on the estrogen receptor subtype and the specific tissue compartment involved in the bacterial insult, suggesting that tissue-specific expression of particular sex steroid receptors contributes to the susceptibility to bacterial infections. Furthermore, this gender bias also depends on the effects of sex hormones on specific bacterial species. Finally, since a large number of genes related to immune functions are located on the X chromosome, X-linked mosaicism confers a highly polymorphic gene expression program that allows women to respond with a more expanded immune repertoire as compared with men.

Conclusion

Notwithstanding there is increasing evidence that confirms the sexual dimorphism in certain bacterial infections and the molecular mechanisms associated, further studies are required to clarify conflicting data and to determine the role of specific hormone receptors involved in the gender bias of bacterial infections, as well as their potential as therapeutic targets.

Gastrointestinal dysbiosis and the use of fecal microbial transplantation in Clostridium difficile infection

The impact of antibiotics on the human gut microbiota is a significant concern. Antibiotic-associated diarrhea has been on the rise for the past few decades with the increasing usage of antibiotics. Clostridium difficile infections (CDI) have become one of the most prominent types of infectious diarrheal disease, with dramatically increased incidence in both the hospital and community setting worldwide. Studies show that variability in the innate host response may in part impact upon CDI severity in patients. That being said, CDI is a disease that shows the most prominent links to alterations to the gut microbiota, in both cause and treatment. With recurrence rates still relatively high, it is important to explore alternative therapies to CDI. Fecal microbiota transplantation (FMT) and other types of bacteriotherapy have become exciting avenues of treatment for CDI. Recent clinical trials have generated excitement for the use of FMT as a therapeutic option for CDI; however, the exact components of the human gut microbiota needed for protection against CDI have remained elusive. Additional investigations on the effects of antibiotics on the human gut microbiota and subsequent CDI will help reduce the socioeconomic burden of CDI and potentially lead to new therapeutic modalities.

ClosIndb: A resource for computationally derived information from clostridial genomes

Over the past few years, several clostridial genomes have been sequenced, and since then new sequencing projects are also under way. Clostridia is one of the most sequenced genera, and presently, complete genome sequences of 49 clostridial species are available in public archives. Unraveling this wealth of genomic information opens up potential avenues in clostridial research. In the present study, we have carried out in silico analysis to decipher the genomic data. Subsequently, a web resource, ClosIndb, has been developed which collates the computationally derived information associated with all clostridial genes. It features various aspects of coding regions as well as non-coding regions, such as putative orthologs, proteins physicochemical properties, operons and cis-regulatory elements. It provides users with comparative details of all clostridial proteins across the firmicutes. ClosIndb is a comprehensive resource for all completely sequenced clostridial genomes and is under constant development. ClosIndb is freely accessible at http://bif.uohyd.ac.in/closindb/.

Microbial ecosystems therapeutics: a new paradigm in medicine?

Increasing evidence indicates that the complex microbial ecosystem of the human intestine plays a critical role in protecting the host against disease. This review discusses gut dysbiosis (here defined as a state of imbalance in the gut microbial ecosystem, including overgrowth of some organisms and loss of others) as the foundation for several diseases, and the applicability of refined microbial ecosystem replacement therapies as a future treatment modality. Consistent with the concept of a 'core' microbiome encompassing key functions required for normal intestinal homeostasis, 'Microbial Ecosystem Therapeutics' (MET) would entail replacing a dysfunctional, damaged ecosystem with a fully developed and healthy ecosystem of 'native' intestinal bacteria. Its application in treating Clostridium difficile infection is discussed and possible applications to other diseases such as ulcerative colitis, obesity, necrotising enterocolitis, and regressive-type autism are reviewed. Unlike conventional probiotic therapies that are generally limited to a single strain or at most a few strains of bacteria 'Microbial Ecosystem Therapeutics' would utilise whole bacterial communities derived directly from the human gastrointestinal tract. By taking into account the intrinsic needs of the entire microbial ecosystem, MET would emphasise the rational design of healthy, resilient and robust microbial communities that could be used to maintain or restore human health. More than simply a new probiotic treatment, this emerging paradigm in medicine may lead to novel strategies in treating and managing a wide variety of human diseases.