Depression, antidepressant medications, and risk of Clostridium difficile infection

The sympathetic nervous system drives hyperinflammatory responses to Clostridioides difficile infection

Clostridioides difficile infection (CDI) is a leading cause of hospital-acquired infections in the United States, known for triggering severe disease by hyperactivation of the host response. In this study, we determine the impact of the sympathetic nervous system (SNS) on CDI disease severity. Mouse models of CDI are administered inhibitors of SNS activity prior to CDI. Chemical sympathectomy or pharmacological inhibition of norepinephrine synthesis greatly reduces mortality and disease severity in the CDI model. Pharmacological blockade or genetic ablation of the alpha 2 adrenergic receptor ameliorates intestinal inflammation, disease severity, and mortality rate. These results underscore the role of the SNS and the alpha 2 adrenergic receptor in CDI pathogenesis and suggest that targeting neural systems could be a promising approach to therapy in severe disease.

Loratadine as an Anti-inflammatory Agent Against Clostridium difficile Toxin B

BACKGROUND

Clostridium difficile infection (CDI) is a debilitating nosocomial infection. C. difficile produces toxins A and B, which cause inflammation. Existing therapies have issues with recurrence, cost, and safety. We aim to discover a safe, effective, and economical nonmicrobiological therapeutic approach against CDI.

METHODS

We included human primary peripheral blood mononuclear cells (PBMCs), fresh human colonic explants, and humanized HuCD34-NCG mice. Toxin A+B+ VPI 10463 and A-B+ ribotype 017 C. difficile strains were used. We used single-cell RNA profiling and high-throughput screening to find actionable toxin B-dependent pathways in PBMCs.

RESULTS

Histamine 1 receptor-related drugs were found among the hit compounds that reversed toxin-mediated macrophage inflammatory protein (MIP) 1α expression in PBMCs. We identified loratadine as the safest representative antihistamine for therapeutic development. Loratadine inhibited toxin B-induced MIP-1α secretion in fresh human colonic tissues. Oral loratadine (10 mg/kg/d) maintained survival, inhibited intestinal CCl3 messenger RNA expression, and prevented vancomycin-associated recurrence in the VPI 10463-infected mice and ribotype 017-infected hamsters. Splenocytes from loratadine-treated mice conferred anti-inflammatory effects to the VPI 10463-infected T/B-cell--deficient Rag-/- mice. Oral loratadine suppressed human MIP-1α expression in monocytes/macrophages in toxin B-expressing ribotype 017-infected humanized HuCD34-NCG mice.

CONCLUSIONS

Loratadine may be repurposed to optimize existing therapies against CDI.

The 3 Ds: Depression, Dysbiosis, and Clostridiodes difficile

This paper explores the intricate relationship between depression, gut dysbiosis, and Clostridioides difficile infections, collectively termed "The 3 Ds". Depression is a widespread mental disorder increasing in prevalence. It is recognized for its societal burden and complex pathophysiology, encompassing genetic, environmental, and microbiome-related factors. The consequent increased use of antidepressants has led to growing concerns about their effects on the gut microbiome. Various classes of antidepressants and antipsychotics show antimicrobial activity, potentially leading to shifts in the gut microbiome and contributing to the development of dysbiosis. Dysbiosis, in turn, can predispose individuals to opportunistic infections like C. difficile, a significant healthcare concern due to its high recurrence rates and severe impact on patients' quality of life. Further, the link between antidepressant use and an increased risk of C. difficile infection (CDI) is explored and, finally, the emergence of live biotherapeutic products as novel treatment options for recurrent CDI is discussed.

Progress of research on the treatment of depression by traditional Chinese medicine prescriptions

Depression is a common psychiatric disorder that belongs to the category of "Depression Syndrome" in traditional Chinese medicine (TCM), and its etiology and pathogenesis are complex and unclear. It is characterized by high prevalence, high disability rate, and high recurrence rate, which seriously affect human health, and its treatment has become a research hotspot worldwide. At present, the antidepressants commonly used in the clinic are mainly Western medicine (WM), but there are problems such as frequent side effects and poor efficacy. Studies have found that the use of TCM prescriptions in the treatment of depression can achieve the same effect as WM; and when TCM prescriptions are combined with WM, the efficacy can be enhanced while the adverse effects of WM can be reduced. Pharmacological studies related to the treatment of depression with traditional Chinese medicine prescriptions (TCMPs) have focused on the neurobiochemical system, gut microbes, and energy metabolism in mitochondria. No one has yet reviewed the pharmacological mechanism of TCMPs for depression. So, this paper reviews the pharmacological mechanism of TCMPs for depression from the perspective of TCMPs, introduces the progress of research on classical TCMPs for depression and their antidepressant mechanism. This article aims to promote the application of TCMPs in the clinic and provide a new therapeutic idea for the clinical treatment of depression.

Breaking the Cycle of Recurrent Clostridioides difficile Infections: A Narrative Review Exploring Current and Novel Therapeutic Strategies

Clostridioides difficile is a toxin-producing bacteria that is a main cause of antibiotic-associated diarrhea. Clostridioides difficile infections (CDI) are associated with disruptions within the gastrointestinal (GI) microbiota which can be further exacerbated by CDI-targeted antibiotic treatment thereby causing recurrent CDI (rCDI) and compounding the burden placed on patients and the healthcare system. Treatment of rCDI consists of antibiotics which can be paired with preventative therapeutics, such as bezlotoxumab or fecal microbiota transplants (FMTs), if sustained clinical response is not obtained. Newer preventative strategies have been recently approved to assist in restoring balance within the GI system with the goal of preventing recurrent infections.

Confounder or Confederate? The Interactions Between Drugs and the Gut Microbiome in Psychiatric and Neurological Diseases

The gut microbiome is emerging as an important factor in signaling along the gut-brain axis. The intimate physiological connection between the gut and the brain allows perturbations in the microbiome to be directly transmitted to the central nervous system and thereby contribute to psychiatric and neurological diseases. Common microbiome perturbations result from the ingestion of xenobiotic compounds including pharmaceuticals such as psychotropic drugs. In recent years, a variety of interactions between these drug classes and the gut microbiome have been reported, ranging from direct inhibitory effects on gut bacteria to microbiome-mediated drug degradation or sequestration. Consequently, the microbiome may play a critical role in influencing the intensity, duration, and onset of therapeutic effects, as well as in influencing the side effects that patients may experience. Furthermore, because the composition of the microbiome varies from person to person, the microbiome may contribute to the frequently observed interpersonal differences in the response to these drugs. In this review, we first summarize the known interactions between xenobiotics and the gut microbiome. Then, for psychopharmaceuticals, we address the question of whether these interactions with gut bacteria are irrelevant for the host (i.e., merely confounding factors in metagenomic analyses) or whether they may even have therapeutic or adverse effects.

Potential effects of the most prescribed drugs on the microbiota-gut-brain-axis: A review

The link between drug-induced dysbiosis and its influence on brain diseases through gut-residing bacteria and their metabolites, named the microbiota-gut-brain axis (MGBA), remains largely unexplored. This review investigates the effects of commonly prescribed drugs (metformin, statins, proton-pump-inhibitors, NSAIDs, and anti-depressants) on the gut microbiota, comparing the findings with altered bacterial populations in major brain diseases (depression, multiple sclerosis, Parkinson's and Alzheimer's). The report aims to explore whether drugs can influence the development and progression of brain diseases via the MGBA. Central findings indicate that all explored drugs induce dysbiosis. These dysbiosis patterns were associated with brain disorders. The influence on brain diseases varied across different bacterial taxa, possibly mediated by direct effects or through bacterial metabolites. Each drug induced both positive and negative changes in the abundance of bacteria, indicating a counterbalancing effect. Moreover, the above-mentioned drugs exhibited similar effects, suggesting that they may counteract or enhance each other's effects on brain diseases when taken together by comorbid patients. In conclusion, the interplay of bacterial species and their abundances may have a greater impact on brain diseases than individual drugs or bacterial strains. Future research is needed to better understand drug-induced dysbiosis and the implications for brain disease pathogenesis, with the potential to develop more effective therapeutic options for patients with brain-related diseases.

A Real-World Study on the Clinical Characteristics, Outcomes, and Relationship between Antibiotic Exposure and Clostridioides difficile Infection

Clostridioides difficile is a Gram-positive bacteria that causes nosocomial infections, significantly impacting public health. In the present study, we aimed to describe the clinical characteristics, outcomes, and relationship between antibiotic exposure and Clostridioides difficile infection (CDI) in patients based on reports from two databases. Thus, we conducted a retrospective study of patients diagnosed with CDI from Sibiu County Clinical Emergency Hospital (SCCEH), Romania, followed by a descriptive analysis based on spontaneous reports submitted to the EudraVigilance (EV) database. From 1 January to 31 December 2022, we included 111 hospitalized patients with CDI from SCCEH. Moreover, 249 individual case safety reports (ICSRs) from EVs were analyzed. According to the data collected from SCCEH, CDI was most frequently reported in patients aged 65-85 years (66.7%) and in females (55%). In total, 71.2% of all patients showed positive medical progress. Most cases were reported in the internal medicine (n = 30, 27%), general surgery (n = 26, 23.4%), and infectious disease (n = 22, 19.8%) departments. Patients were most frequently exposed to ceftriaxone (CFT) and meropenem (MER). Also, in the EV database, most CDI-related ADRs were reported for CFT, PIP/TAZ (piperacillin/tazobactam), MER, and CPX (ciprofloxacin). Understanding the association between previous antibiotic exposure and the risk of CDI may help update antibiotic stewardship protocols and reduce the incidence of CDI by lowering exposure to high-risk antibiotics.

Does this patient have Clostridioides difficile infection? A systematic review and meta-analysis

BACKGROUND

The clinical features and predictors of Clostridioides difficile infection overlap with many conditions.

OBJECTIVES

We performed a systematic review to evaluate the diagnostic utility of clinical features (clinical examination, risk factors, laboratory tests, and radiographic findings) associated with C. difficile.

METHODS

Systematic review and meta-analysis of diagnostic features for C. difficile.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched up to September 2021.

STUDY ELIGIBILITY CRITERIA

Studies that reported clinical features of C. difficile, a valid reference standard test for confirming diagnosis of C. difficile, and a comparison among patients with a positive and negative test result.

PARTICIPANTS

Adult and paediatric patients across diverse clinical settings.

OUTCOMES

Sensitivity, specificity, likelihood ratios.

REFERENCE STANDARD

Stool nucleic acid amplification tests, enzyme immunoassays, cell cytotoxicity assay, and stool toxigenic culture.

ASSESSMENT OF RISK OF BIAS

Rational Clinical Examination Series and Quality Assessment of Diagnostic Accuracy Studies-2.

METHODS OF DATA SYNTHESIS

Univariate and bivariate analyses.

RESULTS

We screened 11 231 articles of which 40 were included, enabling the evaluation of 66 features for their diagnostic utility for C. difficile (10 clinical examination findings, 4 laboratory tests, 10 radiographic findings, prior exposure to 13 antibiotic types, and 29 clinical risk factors). Of the ten features identified on clinical examination, none were significantly clinically associated with increased likelihood of C. difficile infection. Some features that increased likelihood of C. difficile infection were stool leukocytes (LR+ 5.31, 95% CI 3.29-8.56) and hospital admission in the prior 3 months (LR+ 2.14, 95% CI 1.48-3.11). Several radiographic findings also strongly increased the likelihood of C. difficile infection like ascites (LR+ 2.91, 95% CI 1.89-4.49).

DISCUSSION

There is limited utility of bedside clinical examination alone in detecting C. difficile infection. Accurate diagnosis of C. difficile infection requires thoughtful clinical assessment for interpretation of microbiologic testing in all suspected cases.

ANTIDEPRESSANT MEDICATIONS ARE ASSOCIATED WITH INCREASED RISK OF HOSPITAL-ACQUIRED CLOSTRIDIOIDES DIFFICILE INFECTION: A POPULATION-BASED STUDY

WHAT IS ALREADY KNOWN

•The rate and severity of Clostridioides difficile infection (CDI) has increased throughout North America, the United Kingdom, and Europe. •Scattered evidence about the association of CDI with antidepressant medications use exists in the literature so far. What are the new findings: •The risk of Clostridioides difficile infection is higher in patients who are on mirtazapine, nortriptyline, or trazodone. •The prevalence rate of Clostridioides difficile infection in patients who were using antidepressant medications and the ones who did not, increased with age. Background - During the past decade, Clostridioides difficile infection (CDI) has become the most common cause of antibiotic-associated diarrhea. Several risk factors have been implicated. Scattered evidence about the association of CDI with antidepressant medications use exists in the literature so far. Therefore, we aim to investigate whether the risk of developing CDI is increased in hospitalized patients using antidepressant medications.Methods - Patients who were hospitalized were included in our cohort. We excluded individuals aged less than 18 years. A multivariate regression analysis was performed to calculate the risk of CDI accounting for potential confounders. Results - The risk of CDI in hospitalized patients was increased in individuals diagnosed with inflammatory bowel disease (OR: 4.44; 95%CI: 4.35-4.52), and in patients using clindamycin (OR: 1.55; 95%CI: 1.53-1.57), beta-lactam antibiotics (OR: 1.62; 95%CI: 1.60-1.64), PPI (OR: 3.27; 95%CI: 3.23-3.30), trazodone (OR: 1.31; 95%CI: 1.29-1.33), nortriptyline (OR: 1.25; 95%CI: 1.21-1.28), and mirtazapine (OR: 2.50; 95%CI: 2.46-2.54). After controlling for covariates, the risk of CDI was not increased in patients who were taking fluoxetine (OR: 0.94; 95%CI: 0.92-0.96). Conclusion - In contrary to fluoxetine; mirtazapine, nortriptyline, and trazodone were associated with increased risk of CDI in hospitalized patients.

Microbiota-gut-brain axis mechanisms in the complex network of bipolar disorders: potential clinical implications and translational opportunities

Bipolar disorders (BD) represent a severe leading disabling mental condition worldwide characterized by episodic and often progressive mood fluctuations with manic and depressive stages. The biological mechanisms underlying the pathophysiology of BD remain incompletely understood, but it seems that there is a complex picture of genetic and environmental factors implicated. Nowadays, gut microbiota is in the spotlight of new research related to this kind of psychiatric disorder, as it can be consistently related to several pathophysiological events observed in BD. In the context of the so-called microbiota-gut-brain (MGB) axis, it is shown to have a strong influence on host neuromodulation and endocrine functions (i.e., controlling the synthesis of neurotransmitters like serotonin or mediating the activation of the hypothalamic-pituitary-adrenal axis), as well as in modulation of host immune responses, critically regulating intestinal, systemic and brain inflammation (neuroinflammation). The present review aims to elucidate pathophysiological mechanisms derived from the MGB axis disruption and possible therapeutic approaches mainly focusing on gut microbiota in the complex network of BD. Understanding the mechanisms of gut microbiota and its bidirectional communication with the immune and other systems can shed light on the discovery of new therapies for improving the clinical management of these patients. Besides, the effect of psychiatric drugs on gut microbiota currently used in BD patients, together with new therapeutical approaches targeting this ecosystem (dietary patterns, probiotics, prebiotics, and other novelties) will also be contemplated.

Disturbances of purine and lipid metabolism in the microbiota-gut-brain axis in male adolescent nonhuman primates with depressive-like behaviors

INTRODUCTION

Major depressive disorder (MDD) in adolescents is a widespread and growing global public health concern with unique characteristics and pathophysiological mechanisms that are distinct from MDD in adults.

OBJECTIVE

The purpose of our work was to address this knowledge gap about the unique characteristics and pathophysiological mechanisms of adolescent depression from a microbiota-gut-brain (MGB) axis perspective.

METHOD

Ten healthy male cynomolgus macaques (Macaca fascicularis) were paired into five pairs based on age and body weight, and two cynomolgus macaques from each pair were randomly allocated to chronic unpredictable mild stress group, or unstressed control group. At endpoint, microbe composition from cecum, ascending colon, transverse colon, and descending colon were analyzed by metagenome sequencing, and the metabolite profiles of MGB axis including central (prefrontal cortex, hippocampus and amygdala) and peripheral (plasma, gut and feces of cecum, ascending colon, transverse colon and descending colon) samples were analyzed by metabolomic profiling. Then, we compare the gut microbiome and metabolic signatures in MGB axis between adolescent and adult depressed macaques.

RESULTS

The microbial composition and gut-brain metabolic signatures were widely divergent between adolescent and adult depressed macaques, though the phylum Firmicutes and lipid metabolism pathways were persistently altered in both populations. Purine and arginine biosynthesis metabolism were a specific hallmark of adolescent depressed macaques, while fatty acyl metabolism was specially altered in adult. These differential metabolic pathways in adolescent and adult depressed macaques were mainly mapped into the prefrontal cortex and hippocampus, respectively. Notably, the genus Clostridium and Haemophilus, characteristically disturbed in adolescent depressed macaques but not in adult, were also significantly associated with the majority of purine metabolites in MGB axis.

CONCLUSION

These findings provide a new framework describing divergent pathophysiological mechanisms between adolescent and adult depression, and may open new windows for more effective treatment strategies of adolescent depression.

The burden of CDI in the United States: a multifactorial challenge

Clostridioides difficile infection (CDI) affects approximately 500,000 patients annually in the United States, of these around 30,000 will die. CDI carries significant burdens including clinical, social and economic. While healthcare-associated CDI has declined in recent years, community-associated CDI is on the rise. Many patients are also impacted by recurrent C. difficile infections (rCDI); up to 35% of index CDI will recur and of these up to 60% will further recur with multiple recurrences observed. The range of outcomes adversely affected by rCDI is significant and current standard of care does not alter these recurrence rates due to the damaged gut microbiome and subsequent dysbiosis. The clinical landscape of CDI is changing, we discuss the impact of CDI, rCDI, and the wide range of financial, social, and clinical outcomes by which treatments should be evaluated.

Clinical significance of microbiota changes under the influence of psychotropic drugs. An updated narrative review

Relationship between drugs and microbiota is bilateral. Proper composition thus function of microbiota is a key to some medications used in modern medicine. However, there is also the other side of the coin. Pharmacotherapeutic agents can modify the microbiota significantly, which consequently affects its function. A recently published study showed that nearly 25% of drugs administered to humans have antimicrobial effects. Multiple antidepressants are antimicrobials,. and antibiotics with proven antidepressant effects do exist. On the other hand, antibiotics (e.g., isoniaside, minocycline) confer mental phenotype changes, and adverse effects caused by some antibiotics include neurological and psychological symptoms which further supports the hypothesis that intestinal microbiota may affect the function of the central nervous system. Here we gathered comprehensively data on drugs used in psychiatry regarding their antimicrobial properties. We believe our data has strong implications for the treatment of psychiatric entities. Nevertheless the study of ours highlights the need for more well-designed trials aimed at analysis of gut microbiota function.

Validation of a Health-Related Quality of Life Questionnaire in Patients With Recurrent Clostridioides difficile Infection in ECOSPOR III, a Phase 3 Randomized Trial

BACKGROUND

Debilitating symptoms of recurrent Clostridioides difficile infection (rCDI) often lead to long-term effects on health-related quality-of-life (HRQOL). In ECOSPOR III, SER-109, an investigational oral microbiome therapeutic, was superior to placebo in reducing rCDI. We investigated the validity, reliability, and responsiveness of a 32-item, CDI-specific questionnaire-the Clostridium difficile Quality of Life Survey (Cdiff32)-across mental, physical, and social domains in patients with rCDI.

METHODS

In this post hoc analysis of a phase 3 clinical trial, 182 outpatients with rCDI completed Cdiff32 and EQ-5D at baseline and at 1 and 8 weeks. Cdiff32 was evaluated for item performance, internal reliability, and convergent validity. To assess known-groups validity, Cdiff32 scores were compared by disease recurrence status at week 1; internal responsiveness was evaluated in the nonrecurrent disease group by 8 weeks by means of paired t test.

RESULTS

All 182 patients (mean age [standard deviation], 65.5 [16.5] years; 59.9% female) completed baseline Cdiff32. Confirmatory factor analysis identified 3 domains (physical, mental, and social relationships) with good item fit. High internal reliability was demonstrated (Cronbach α = 0.94 with all subscales >0.80). Convergent validity was evidenced by significant correlations between Cdiff32 subscales and EQ-5D (r = 0.29-0.37; P < .001). Cdiff32 differentiated patients by disease recurrence status at week 1 (effect sizes, 0.38-0.42; P < .05 overall), with significant improvement from baseline through week 8 in patients with nonrecurrent disease at week 1 (effect sizes, 0.75-1.02; P < .001 overall).

CONCLUSIONS

Cdiff32 is a valid, reliable, and responsive disease-specific HRQOL questionnaire that is fit for purpose for interventional treatment trials. The significant improvement in patients with nonrecurrent disease by 8 weeks demonstrates the negative impact of rCDI on HRQOL.

Antidepressants promote the spread of extracellular antibiotic resistance genes via transformation

The development of antibiotic resistance as an unavoidable consequence of the application of antimicrobials is a significant concern for human health. Antidepressants are being increasingly consumed globally. Human gut microbial communities are frequently exposed to antidepressants, yet little is known about the interaction between antidepressants and antibiotic resistance. This study aimed to investigate whether antidepressants can accelerate the dissemination of antibiotic resistance by increasing the rate of the horizontal transfer of antibiotic resistance genes (ARGs). Results demonstrated that some of the commonly-prescribed antidepressants (Duloxetine, Sertraline, Fluoxetine and Bupropion) at clinically relevant concentrations can significantly (n = 9; padj < 0.01) promote the transformation of extracellular ARGs into Acinetobacter baylyi ADP1 for a maximum of 2.3-fold, which is primarily associated with the overproduction of reactive oxygen species. The increased cell membrane permeability and porosity, stimulated transcription and translation of competence, SOS response, universal stress response and ATP synthesis-related genes are also associated with antidepressants-enhanced transformation. This study demonstrated that some antidepressants can speed up the spread of antibiotic resistance by promoting the transformation of ARGs, which emphasizes the necessity to assess the potential risks of antidepressants in spreading antibiotic resistance during clinical antidepressant applications.

Validity and reliability of the Patient Health Questionnaire scale (PHQ-9) among university students of Bangladesh

This study investigated the reliability and factorial validity of Patient Health Questionnaire-9 (PHQ-9) in the context of university students in Bangladesh. The research aimed to assess whether the original one-dimensional model or a model containing both somatic and cognitive-emotional factors is appropriate in the case of a sample of university students. A repeated cross-sectional survey design based on convenience sampling was used to collect data from 677 university students from both public and private universities. The factor structure of the PHQ-9 was assessed using confirmatory factor analysis (CFA). Measurement invariances were assessed across gender, type of university, level of education and victim of domestic violence. Its convergent validity was determined by investigating its correlations with Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire Anxiety-Depression Scale (PHQ-ADS). Results showed excellent reliability of PHQ-9 as measured by both Cronbach's α and McDonald's ω. CFA suggested that a modified one-factor model where the error variances between item-3 ('sleeping difficulties') and item-6 ('feeling as a failure'), item-6 and item-9 ('suicidal thoughts'), item-4 ('feeling tired') and item-9, item-3 and item-9 were allowed to covary is appropriate for the sample. This model provided high values of comparative fit index (CFI), goodness of fit index (GFI), and Tucker Lewis Index (TLI), low value of standardized root mean square residual (SRMR) and a non-significant root mean square error of approximation (RMSEA) as well as a high Factor Determinacy Score Coefficient. Correlation between PHQ-9 and GAD-7 was 0.751 and 0.934 between PHQ-9 and PHQ-ADS. Finally, the model is strictly invariant across gender and university type. Overall, the study provided support for modified unidimensional structure for PHQ-9 and showed high internal consistency along with good convergent validity.

Prospective associations between depression and risk of hospitalisation for infection: Findings from the UK Biobank

BACKGROUND

Associations between depression and non-communicable disease have been well-described. However, the evidence for its role in the development of infectious disease is less understood. We aimed to examine prospective associations between depression and risk of hospitalisation for infection in middle-aged adults from the UK Biobank (linked with Hospital Episode Statistics) and assessed the role of several depression-related factors.

METHODS

We assessed prospective associations between depression status at the baseline assessment (2006-2010) and hospitalisations for infection up to the end of March 2016 in 460,418 middle-aged adults enrolled in the UK Biobank (mean age = 56.23 ± 8.11 years, 53.5% female). Cox regression was used to assess associations between depression and subsequent hospitalisations for any infections, as well as infection subtypes, viral infections, and bacterial infections. Amongst those with depression, we also examined the role of depression duration, the age of onset, and the use of antidepressants in hospitalisation risk.

RESULTS

Depression at baseline was prospectively associated with an increased risk of hospitalisation for infection (adjusted hazard ration (aHR) = 1.20, 95% confidence interval (CI) = 1.16 to 1.25). This association was found for all infection subtypes apart from infections of the central nervous system (p = 0.911) and the skin (p = 0.313). Receipt of a depression diagnosis in late adulthood and use of antidepressants (but only in those with none/mild depressive symptoms at baseline) increased the risk of hospitalisation for infection amongst those with depression.

CONCLUSIONS

These findings suggest that depression might be a risk factor which could be used to identify those at risk of hospitalisation for infection. Future research is required to understand the underlying factors that might result in this increased risk, so that targeted interventions can be developed.

FUNDING

AD and AR are funded by Guy's Charity grant number EIC180702 (MLTC Challenge Fund); AD and JAT are co-funded by MRC and NIHR through grant number MR/S028188/1. IB is supported by the NIHR Maudsley BRC and by the NIHR Collaboration for Leadership in Applied Health Research and Care South Londnoo at King's College Hospital NHS Foundation Trust, King's College London. The views expressed are those of the author[s] and not necessarily those of the ESRC, NIHR, the Department of Health and Social Care or King's College London.

GPR35 promotes neutrophil recruitment in response to serotonin metabolite 5-HIAA

Rapid neutrophil recruitment to sites of inflammation is crucial for innate immune responses. Here, we reveal that the G-protein-coupled receptor GPR35 is upregulated in activated neutrophils, and it promotes their migration. GPR35-deficient neutrophils are less recruited from blood vessels into inflamed tissue, and the mice are less efficient in clearing peritoneal bacteria. Using a bioassay, we find that serum and activated platelet supernatant stimulate GPR35, and we identify the platelet-derived serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) as a GPR35 ligand. GPR35 function in neutrophil recruitment is strongly dependent on platelets, with the receptor promoting transmigration across platelet-coated endothelium. Mast cells also attract GPR35+ cells via 5-HIAA. Mice deficient in 5-HIAA show a loss of GPR35-mediated neutrophil recruitment to inflamed tissue. These findings identify 5-HIAA as a GPR35 ligand and neutrophil chemoattractant and establish a role for platelet- and mast cell-produced 5-HIAA in cell recruitment to the sites of inflammation and bacterial clearance.

Altered metabolome and microbiome features provide clues in understanding irritable bowel syndrome and depression comorbidity

Irritable bowel syndrome (IBS) is one of the functional gastrointestinal disorders characterized by chronic and/or recurrent symptoms of abdominal pain and irregular defecation. Changed gut microbiota has been proposed to mediate IBS; however, contradictory results exist, and IBS-specific microbiota, metabolites, and their interactions remain poorly understood. To address this issue, we performed metabolomic and metagenomic profiling of stool and serum samples based on discovery (n = 330) and validation (n = 101) cohorts. Fecal metagenomic data showed moderate dysbiosis compared with other diseases, in contrast, serum metabolites showed significant differences with greater power to distinguish IBS patients from healthy controls. Specifically, 726 differentially abundant serum metabolites were identified, including a cluster of fatty acyl-CoAs enriched in IBS. We further identified 522 robust associations between differentially abundant gut bacteria and fecal metabolites, of which three species including Odoribacter splanchnicus, Escherichia coli, and Ruminococcus gnavus were strongly associated with the low abundance of dihydropteroic acid. Moreover, dysregulated tryptophan/serotonin metabolism was found to be correlated with the severity of IBS depression in both fecal and serum metabolomes, characterized by a shift in tryptophan metabolism towards kynurenine production. Collectively, our study revealed serum/fecal metabolome alterations and their relationship with gut microbiome, highlighted the massive alterations of serum metabolites, which empower to recognize IBS patients, suggested potential roles of metabolic dysregulation in IBS pathogenesis, and offered new clues to understand IBS depression comorbidity. Our study provided a valuable resource for future studies, and would facilitate potential clinical applications of IBS featured microbiota and/or metabolites.

Risk Factors for Klebsiella Infections among Hospitalized Patients with Preexisting Colonization

Klebsiella commonly colonizes the intestinal tract of hospitalized patients and is a leading cause of health care-associated infections. Colonization is associated with subsequent infection, but the factors determining this progression are unclear. A cohort study was performed, in which intensive care and hematology/oncology patients with Klebsiella colonization based on rectal swab culture were enrolled and monitored for infection for 90 days after a positive swab. Electronic medical records were analyzed for patient factors associated with subsequent infection, and variables of potential significance in a bivariable analysis were used to build a final multivariable model. Concordance between colonizing and infecting isolates was assessed by wzi capsular gene sequencing. Among 2,087 hospitalizations from 1,978 colonized patients, 90 cases of infection (4.3%) were identified. The mean time to infection was 20.6 ± 24.69 (range, 0 to 91; median, 11.5) days. Of 86 typed cases, 68 unique wzi types were identified, and 69 cases (80.2%) were colonized with an isolate of the same type prior to infection. Based on multivariable modeling, overall comorbidities, depression, and low albumin levels at the time of rectal swab collection were independently associated with subsequent Klebsiella infection (i.e., cases). Despite the high diversity of colonizing strains of Klebsiella, there is high concordance with subsequent infecting isolates, and progression to infection is relatively quick. Readily accessible data from the medical record could be used by clinicians to identify colonized patients at an increased risk of subsequent Klebsiella infection.

IMPORTANCEKlebsiella is a leading cause of health care-associated infections. Patients who are intestinally colonized with Klebsiella are at a significantly increased risk of subsequent infection, but only a subset of colonized patients progress to disease. Colonization offers a potential window of opportunity to intervene and prevent these infections, if the patients at greatest risk could be identified. To identify patient factors associated with infection in colonized patients, we studied 1,978 colonized patients. We found that patients with a higher burden of underlying disease in general, depression in particular, and low albumin levels in a blood test were more likely to develop infection. However, these variables did not completely predict infection, suggesting that other host and microbial factors may also be important. The clinical variables associated with infection are readily available in the medical record and could serve as the foundation for developing an integrated risk assessment of Klebsiella infection in hospitalized patients.

Novel risk factors and outcomes in inflammatory bowel disease patients with Clostridioides difficile infection

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at significantly increased risk for Clostridioides difficile infection (CDI) with an increased risk of adverse outcomes including increased in-hospital mortality, IBD treatment failure, re-hospitalization, and high CDI recurrence rates. The existing literature on predictors of these adverse outcomes is limited. We evaluated four potentially modifiable novel risk factors [body mass index (BMI), statin use, opioid use, and antidepressant use] on CDI risk and adverse outcomes in these patients.

METHODS

Using a retrospective design, variables were abstracted from records for patients with IBD and CDI from 2008 to 2013. Statistical analysis comprised descriptive statistics and univariate and multivariate logistic regression analyses.

RESULTS

There were 137 patients with IBD and CDI included in this study. On multivariate analysis controlling for age, 43% of patients in the overweight BMI category had severe or severe, complicated CDI, compared with 22% of patients in the underweight/normal BMI [odds ratio (OR) 2.85, p = 0.02] and 19% in the obese category (OR 3.95, p = 0.04). Statin use was associated with severe or severe, complicated CDI when controlling for age and BMI (OR 5.66, p = 0.01). There was no association between statin use and IBD exacerbations following CDI. Opioid and antidepressant use were not associated with disease severity or frequency of IBD exacerbations following CDI.

CONCLUSIONS

An overweight BMI and statin use were associated with severe or severe, complicated CDI in IBD patients. Further studies are needed to better understand how these factors impact management of patients with IBD to improve clinical outcomes and potentially reduce the risk of complications from CDI.

Updated Review and Meta-Analysis of Probiotics for the Treatment of Clinical Depression: Adjunctive vs. Stand-Alone Treatment

Recent years have seen a rapid increase in the use of gut microbiota-targeting interventions, such as probiotics, for the treatment of psychiatric disorders. The objective of this update review was to evaluate all randomised controlled clinical trial evidence on the efficacy of probiotics for clinical depression. Cochrane guidelines for updated reviews were followed. By searching PubMed and Web of Science databases, we identified 546 new records since our previous review. A total of seven studies met selection criteria, capturing 404 people with depression. A random effects meta-analysis using treatment type (stand-alone vs. adjunctive) as subgroup was performed. The results demonstrated that probiotics are effective in reducing depressive symptoms when administered in addition to antidepressants (SMD = 0.83, 95%CI 0.49-1.17), however, they do not seem to offer significant benefits when used as stand-alone treatment (SMD = -0.02, 95%CI -0.34-0.30). Potential mechanisms of action may be via increases in brain-derived neurotrophic factor (BDNF) and decreases in C-reactive protein (CRP), although limited evidence is available at present. This review offers stronger evidence to support the clinical use of probiotics in depressed populations and provides an insight into the mode of administration more likely to yield antidepressant effects.

Effect of antidepressant use on length of hospitalization in patients on anti-infective therapy

Compared to those without depression, acutely-ill patients with depression hospitalized for an infection usually have poor outcomes, including increased length of stay (LOS).

PURPOSE

The primary objective was to evaluate the LOS between patients receiving an anti-infective with and without any antidepressant use. Secondary objectives were to examine LOS based on acuity of care and age.

METHODS

Using a cross-sectional design, hospitalized adult patients who received anti-infective agents between January 1, 2017 and October 31, 2019 for ≥7 days were included. Univariate and multivariate analyses were conducted to determine statistical significance.

RESULTS

A total of 17,651 patient encounters were included in the study. Of all patient encounters, 5165 (29%) received antidepressants concurrently with anti-infectives, with mean age of 57 years ± 17.3. Patients receiving concurrent antidepressants experienced longer LOS compared with patients not receiving antidepressants [20 vs 16 days, 95% confident interval (CI): 3.98-5.18, p < 0.001]. Stratified by intensive care unit (ICU) admission during hospital encounters and age ≥ 65 years, patients receiving antidepressants had longer LOS (25 vs 18 days, CI: 5.63-8.61, p < 0.001, and 18 vs 15 days, CI: 2.39-4.04, p < 0.001, respectively). After controlling for gender and ethnicity, antidepressant use and ICU admission were independently associated with increased LOS.

CONCLUSION

Patients who received both an antidepressant and an anti-infective agent had significantly increased LOS, including those in the ICU and in the elderly population. Future studies are needed to assess the impact of concomitant antidepressant use on mortality and other clinical outcomes in patients hospitalized with an infection.

The Gut Microbiome in Bipolar Disorder and Pharmacotherapy Management

The gut microbiome is a complex and dynamic community of commensal, symbiotic, and pathogenic microorganisms that exist in a bidirectional relationship with the host. Bacterial functions in the gut play a critical role in healthy host functioning, and its disruption can contribute to many medical conditions. The relationship between gut microbiota and the brain has gained attention in mental health due to the mounting evidence supporting the association of gut bacteria with mood and behavior. Patients with bipolar disorder exhibit an increased frequency of gastrointestinal illnesses such as inflammatory bowel disease, which mechanistically has been linked to microbial community function. While the heterogeneity in microbial communities between individuals might be associated with disease risk, it may also moderate the efficacy or adverse effects associated with the use of medication. The following review highlights published evidence linking the function of gut microbiota both to bipolar disorder risk and to the effect of medications that influence microbiota, inflammation, and mood symptoms.

GABAergic but not Antidepressant Medications Increase Risk for Clostridioides difficile Infection in a National Cohort of Veterans

Background

Clostridioides difficile infection (CDI) is primarily mediated by alterations in the host gut ecosystem. While antibiotic use is the primary risk factor for CDI, other medications that modulate the gut ecosystem, particularly those targeting the gut-brain axis, could impact CDI risk. This study aimed to investigate the association between recent antidepressant and gamma-aminobutyric acid (GABA)-ergic medication use with CDI risk in a national cohort of United States veterans.

Methods

This was a retrospective case-control study of patients seen in Veterans Health Administration facilities from October 2002 to September 2014. CDI and non-CDI control patients were propensity score matched 1:1 using a maximum caliper of 0.0001. Antidepressant and GABAergic medication use 90 days before cohort inclusion were analyzed for CDI association using bivariable and multivariable logistic regression models.

Results

A total of 85 831 patients were included, and 9287 CDI and 9287 control patients were propensity score matched. Antidepressant use overall was not significantly associated with CDI risk (odds ratio [OR], 1.05; 95% CI, 0.98-1.12), although GABAergic medication use was associated with increased risk (OR, 1.81; 95% CI, 1.70-1.92). In multivariable models of individual medications/classes, benzodiazepines had the strongest CDI association (OR, 1.91; 95% CI, 1.77-2.07). SSRIs (OR, 0.88; 95% CI, 0.81-0.95) and bupropion (OR, 0.67; 95% CI, 0.57-0.78) were negatively associated with CDI.

Conclusions

In this national study of veterans, GABAergic medication use was a positive predictor of CDI risk, though antidepressant use was not. Further research is needed to understand biological mechanisms, and confirmatory studies are needed to validate these findings.

Effect of Xiaoyaosan on Colon Morphology and Intestinal Permeability in Rats With Chronic Unpredictable Mild Stress

Purpose

In our present study, a rat depression model induced by 6 weeks of chronic unpredictable mild stress (CUMS) was established, and we investigated how Xiaoyaosan affects the intestinal permeability of depressed rats and alterations in tight-junction proteins (TJs) involved in this process.

Methods

The rat depression model was established using CUMS for 6 consecutive weeks. A total of 40 healthy male Sprague-Dawley rats were randomly sorted into four groups: the control group, CUMS group, Xiaoyaosan group, and fluoxetine group. All groups, excluding the control group, were subjected to the 6-week CUMS program to generate the depression model. Body weight, food intake, and behaviors were observed during the modeling period. Histopathological alterations of colon tissue were evaluated by hematoxylin-eosin staining (H&E), and mucus-containing goblet cells were detected by periodic acid-Schiff (PAS) staining. The ultrastructural morphology of colonic mucosa was observed by transmission electron microscopy. Furthermore, immunohistochemistry (IHC) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to determine the expression of TJs. The concentrations of 5-hydroxytryptamine (5-HT) in the hypothalamus and colon were also assessed using enzyme-linked immunosorbent assay (ELISA).

Results

Treatment of depressed rats with Xiaoyaosan alleviated depression-like behaviors as demonstrated by increases in the total distance traveled, the number of entries into the central area in the open field test, the duration spent in the central area, and sucrose preference. Xiaoyaosan treatment also increased body weight gain and food intake in depressed rats. Moreover, Xiaoyaosan treatment effectively improved the colonic pathological and ultrastructural changes, upregulated the expression of ZO-1, occludin, and claudin-1 in the colon, and increased 5-HT levels in the hypothalamus and colonic mucosa.

Conclusions

Xiaoyaosan treatment attenuates depression-like behaviors caused by CUMS and ameliorates CUMS-induced abnormal intestinal permeability, which may be associated with the expression of TJs. These results suggest that Xiaoyaosan exerts an antidepressant effect that may be related to an improvement of intestinal barrier function via the brain-gut axis.

From Nursery to Nursing Home: Emerging Concepts in Clostridioides difficile Pathogenesis

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium that infects the human gastrointestinal tract, causing a wide range of disorders that vary in severity from mild diarrhea to toxic megacolon and/or death. Over the past decade, incidence, severity, and costs associated with C. difficile infection (CDI) have increased dramatically in both the pediatric and adult populations. The factors driving this rapidly evolving epidemiology remain largely unknown but are likely due in part to previously unappreciated host, microbiota, and environmental factors. In this review, we will cover the risks and challenges of CDI in adult and pediatric populations and examine asymptomatic colonization in infants. We will also discuss the emerging role of diet, pharmaceutical drugs, and pathogen-microbiota interactions in C. difficile pathogenesis, as well as the impact of host-microbiota interactions in the manifestation of C. difficile-associated disease. Finally, we highlight new areas of research and novel strategies that may shed light on this complex infection and provide insights into the future of microbiota-based therapeutics for CDI.

Targeting the microbiota in pharmacology of psychiatric disorders

There is increasing interest in the role of the gut microbiota in health and disease. In particular, gut microbiota influences the Central Nervous System (CNS) development and homeostasis through neural pathways or routes involving the immune and circulatory systems. The CNS, in turn, shapes the intestinal flora through endocrine or stress-mediated responses. These overall bidirectional interactions, known as gut microbiota-brain axis, profoundly affect some brain functions, such as neurogenesis and the production of neurotransmitters, up to influence behavioral aspects of healthy subjects. Consequently, a dysfunction within this axis, as observed in case of dysbiosis, can have an impact on the behavior of a given individual (e.g. anxiety and depression) or on the development of pathologies affecting the CNS, such as autism spectrum disorders and neurodegenerative diseases (e.g. Alzheimer's disease and Parkinson's disease). It should be considered that the whole microbiota has a significant role not only on aspects concerning human physiology, such as harvesting of nutrients and energy from the ingested food or production of a wide range of bioactive compounds, but also has positive effects on the gastrointestinal barrier function and actively contributes to the pharmacokinetics of several compounds including neuropsychiatric drugs. Indeed, the microbiota is able to affect drug absorption and metabolism up to have an impact on drug activity and/or toxicity. On the other hand, drugs are able to shape the human gut microbiota itself, where these changes may contribute to their pharmacologic profile. Therefore, the emerging picture on the complex drug-microbiota bidirectional interplay will have considerable implications in the future not only in terms of clinical practice but also, upstream, on drug development.

Finding intestinal fortitude: Integrating the microbiome into a holistic view of depression mechanisms, treatment, and resilience

Depression affects at least 322 million people globally, or approximately 4.4% of the world's population. While the earnestness of researchers and clinicians to understand and treat depression is not waning, the number of individuals suffering from depression continues to increase over and above the rate of global population growth. There is a sincere need for a paradigm shift. Research in the past decade is beginning to take a more holistic approach to understanding depression etiology and treatment, integrating multiple body systems into whole-body conceptualizations of this mental health affliction. Evidence supports the hypothesis that the gut microbiome, or the collective trillions of microbes inhabiting the gastrointestinal tract, is an important factor determining both the risk of development of depression and persistence of depressive symptoms. This review discusses recent advances in both rodent and human research that explore bidirectional communication between the gut microbiome and the immune, endocrine, and central nervous systems implicated in the etiology and pathophysiology of depression. Through interactions with circulating inflammatory markers and hormones, afferent and efferent neural systems, and other, more niche, pathways, the gut microbiome can affect behavior to facilitate the development of depression, exacerbate current symptoms, or contribute to treatment and resilience. While the challenge of depression may be the direst mental health crisis of our age, new discoveries in the gut microbiome, when integrated into a holistic perspective, hold great promise for the future of positive mental health.

Gut Microbiota and Colonization Resistance against Bacterial Enteric Infection

The gut microbiome is critical in providing resistance against colonization by exogenous microorganisms. The mechanisms via which the gut microbiota provide colonization resistance (CR) have not been fully elucidated, but they include secretion of antimicrobial products, nutrient competition, support of gut barrier integrity, and bacteriophage deployment. However, bacterial enteric infections are an important cause of disease globally, indicating that microbiota-mediated CR can be disturbed and become ineffective. Changes in microbiota composition, and potential subsequent disruption of CR, can be caused by various drugs, such as antibiotics, proton pump inhibitors, antidiabetics, and antipsychotics, thereby providing opportunities for exogenous pathogens to colonize the gut and ultimately cause infection. In addition, the most prevalent bacterial enteropathogens, including Clostridioides difficile, Salmonella enterica serovar Typhimurium, enterohemorrhagic Escherichia coli, Shigella flexneri, Campylobacter jejuni, Vibrio cholerae, Yersinia enterocolitica, and Listeria monocytogenes, can employ a wide array of mechanisms to overcome colonization resistance. This review aims to summarize current knowledge on how the gut microbiota can mediate colonization resistance against bacterial enteric infection and on how bacterial enteropathogens can overcome this resistance.

Misoprostol protects mice against severe Clostridium difficile infection and promotes recovery of the gut microbiota after antibiotic perturbation

Clostridium difficile infection (CDI) is one of the most common nosocomial infections worldwide and an urgent public health threat. Epidemiological and experimental studies have demonstrated an association between nonsteroidal anti-inflammatory drug (NSAID) exposure and enhanced susceptibility to, and severity of, CDI. NSAIDs target cyclooxygenase enzymes and inhibit the production of prostaglandins (PGs), but the therapeutic potential of exogenous introduction of PGs for the treatment of CDI has not been explored. In this study, we report that treatment with the FDA-approved stable PGE₁ analogue, misoprostol, protects mice against C. difficile-associated mortality, intestinal pathology, and CDI-mediated intestinal permeability. Furthermore, we report that the effect of misoprostol on the gastrointestinal tract contributes to increased recovery of the gut microbiota following antibiotic perturbation. Together, these data implicate PGs as an important host-factor associated with recovery to C. difficile-associated disease and demonstrate the potential for misoprostol in the treatment of CDI. Further studies to explore the safety and efficacy of misoprostol treatment of CDI in humans is needed.

Development of a bedside scoring system for predicting a first recurrence of Clostridium difficile-associated diarrhea

PURPOSE

A scoring system for identifying patients at high or low risk for recurrent Clostridium difficile-associated diarrhea (CDAD) is described.

METHODS

A retrospective cohort study was performed using data on adults with CDAD admitted to a 3-hospital system from 2009 to 2014. The primary endpoint was the rate of recurrent CDAD within 60 days of clinical cure of CDAD. Risk factors for CDAD recurrence were identified, and a risk prediction tool was developed using multivariate logistic regression.

RESULTS

The CDAD cure rate in the study cohort (n = 340) was 92.3%; the 60-day recurrence rate was 16.9%. Five factors were significantly associated with high recurrence risk: presence of CDAD at admission, body temperature of >37.8 °C at admission, leukocytosis, nosocomial CDAD, and abdominal distention on CDAD presentation. From that information a risk prediction tool, the CDAD "recurrence score," was developed (1 point is assigned for each factor present, for a maximum score of 5). Validation testing of the recurrence score indicated an area under the receiver operating characteristic curve of 0.72 (95% confidence interval, 0.65-0.80). A score of ≥2 had a negative predictive value of 91%, while a score of ≥4 had a positive predictive value of 70%.

CONCLUSION

If externally validated in future studies, a tool for predicting the risk of recurrent CDAD using data readily available at the time of presentation could allow clinicians to identify patients at high risk for recurrence, address modifiable risk factors, and select tailored treatments to improve patient outcomes.

Analgesic adjuvants modulate morphine-induced immune effects in mice

BACKGROUND

Macrophages, involved in the pathogenesis of pain, express a variety of receptors enabling responsiveness to certain medications, including adjuvant analgesics (AAs), that are effective in neuropathic pain and include drugs not primarily indicated for pain treatment, such as anticonvulsants or antidepressants. Their analgesic effects are likely associated with immunomodulatory activity, that remain undefined. Thus, current research aimed at examining the impact of AAs on morphine-induced effects exerted on mouse immunity.

METHODS

Macrophages from mice treated with morphine with or without gabapentin, amitriptyline or venlafaxine, were either subjected to phagocytosis assay, cultured to evaluate the generation of cytokines, or were pulsed with either corpuscular antigen or hapten and transferred to naive recipients to induce humoral or cellular response, respectively. Active contact hypersensitivity was also elicited in drug-treated mice.

RESULTS

We observed that repeatedly administered morphine and AAs reduced antigen phagocytosis by macrophages. Further, amitriptyline with morphine enhanced basal secretion of cytokines by macrophages, and all drugs tended to decrease LPS-stimulated release of pro-inflammatory cytokines. Morphine and AAs impacted the expression of phagocytosis and antigen-presentation markers on macrophages, which led to the reduced ability of morphine-affected macrophages to induce B-cell secretion of specific antibodies, and the addition of AAs strengthened this effect. Finally, gabapentin and venlafaxine suppressed the contact hypersensitivity reaction, while amitriptyline seemed to have the opposite effect.

CONCLUSIONS

Our study demonstrated a significant anti-inflammatory activity of AAs across a broad spectrum of macrophage immune functions, which is likely critical to their analgesic activity supporting the beneficial effect of morphine.

History of Depression and Increased Risk of Sternal Wound Infection After Cardiothoracic Surgery: A Novel and Potentially Modifiable Risk Factor

Background

Sternal wound infection (SWI) is a leading cause of postoperative disease and death; the risk factors for SWI remain incompletely understood. The goal of the current study was to investigate the relationship between a preoperative history of depression and the risk of SWI after cardiothoracic surgery.

Methods

Among patients undergoing cardiothoracic surgery in a major academic medical center between 2007 and 2012, those in whom SWI developed (n = 129) were matched, by date of surgery, with those in whom it did not (n = 258). Multivariable logistic regression was used to examine the strength of relationships between risk factors and development of infection. History of depression was defined as a composite variable to increase the sensitivity of detection.

Results

History of depression as defined by our composite variable was associated with increased risk of SWI (adjusted odds ratio, 2.4; 95% confidence interval, 1.2–4.7; P = .01). Staphylococcus aureus was the most common organism isolated.

Conclusions

History of depression was associated with increased risk of SWI. Future prospective studies are warranted to further investigate this relationship. Depression is highly treatable, and increased efforts to identify and treat depression preoperatively may be a critical step toward preventing infection-related disease and death.

Clostridium difficile infection in Johannesburg, South Africa

OBJECTIVES

The incidence of Clostridium difficile infection is increasing, resulting in significant in-patient morbidity and mortality. We describe the characteristics of Clostridium difficile infection in patients admitted to a tertiary Academic Hospital in Johannesburg, South Africa.

METHODS

This was a retrospective record review of 154 adult in-patients with confirmed Clostridium difficile infection undertaken between 1 January 2013 and 30 June 2014.

RESULTS

Overall, 83 (53.9%) patients were female and the median age was 39 years. The most common symptoms were watery diarrhea (92.9%) and fever (27.3%). Overall, 145 (97.9%) patients had been exposed to antibiotics in the last 30 days, 54 (35.1%) to immunosuppressives, 48 (31.2%) to gastric acid suppressants, and 65 (42.2%) patients had previous hospital admissions. Only two cases were community-acquired. In total, 73 (47.4%) patients died. There was no difference in outcomes of HIV-positive patients compared to HIV-negative patients; however, the clinical features were more marked in the HIV-negative patients. Non-survivors tended to have a greater number of severity indicators compared to the survivors.

CONCLUSION

Patients with Clostridium difficile infection in this study were younger and had a higher mortality than that reported in the Western world. Most infections were hospital-acquired.

Gut-brain axis metabolic pathway regulates antidepressant efficacy of albiflorin

The gut microbiota is increasingly recognized to influence brain function through the gut-brain axis. Albiflorin, an antidepressant natural drug in China with a good safety profile, is difficult to absorb and cannot be detected in the brain after oral administration. Accordingly, the antidepressant mechanism of albiflorin in vivo has not been elucidated clearly. Methods: We identified benzoic acid as the characteristic metabolite of albiflorin in vivo and in vitro, then discovered the roles of gut microbiota in the conversion of albiflorin by carboxylesterase. Pharmacodynamic and pharmacokinetic studies were performed for the antidepressant activities of albiflorin in animals, and the efficacy of benzoic acid in inhibiting D-amino acid oxidase (DAAO) in brain was further investigated. Results: We validated that gut microbiota transformed albiflorin to benzoic acid, a key metabolite in the intestine that could cross the blood-brain barrier and, as an inhibitor of DAAO in the brain, improved brain function and exerted antidepressant activity in vivo. Intestinal carboxylesterase was the crucial enzyme that generated benzoic acid from albiflorin. Additionally, the regulatory effect of albiflorin on the gut microbiota composition was beneficial to alleviate depression. Conclusion: Our findings suggest a novel gut-brain dialogue through intestinal benzoic acid for the treatment of depression and reveal that the gut microbiota may play a causal role in the pathogenesis and treatment of the central nervous system disease.

Clostridium difficile infection in the USA: incidence and associated factors in revision total knee arthroplasty patients

INTRODUCTION

Revision total knee arthroplasty (TKA) procedures performed secondary to periprosthetic joint infection (PJI) are associated with significant morbidity and mortality. These poor outcomes may be further complicated by postoperative infection requiring antibiotics. However, antibiotic overuse may suppress patients' bacterial flora, leading to Clostridium difficile infection (CDI). Therefore, we aimed to study the: (1) incidence; (2) costs; and (3) risk factors associated with CDI in revision TKA patients.

METHODS

The National Inpatient Sample database was queried for individuals diagnosed with PJI who underwent revision TKA between 2009 and 2013 (n = 83,806). Patients who developed CDI during their inpatient stay were identified (n = 799). Logistic regression analysis was conducted to assess the association between hospital- and patient-specific characteristics and the development of CDI.

RESULTS

The incidence of CDI after revision TKA was 1.0%. These patients were older (mean age 69.05 vs. 65.52 years), had greater LOS (median 11 vs. 5 days) and greater costs ($30,612.93 vs. 18,873.75), and experienced higher in-hospital mortality (3.6 vs. 0.5%; p < 0.001 for all) compared to those without infection. Patients with CDI were more likely to be treated in urban, not-for-profit, medium/large hospitals in the Northeast or Midwest (p < 0.05 for all) and to have underlying depression (OR 4.267; p = 0.007) or fluid/electrolyte disorders (OR 3.48; p = 0.001).

CONCLUSION

Although CDI is rare following revision TKA, it can have detrimental consequences. We demonstrate that CDI is associated with longer LOS, higher costs, and greater in-hospital mortality. With increased legislative pressure to lower healthcare expenditures, it is crucial to identify means of preventing costly complications.

Indomethacin increases severity of Clostridium difficile infection in mouse model

AIM

To evaluate the effect on the nonsteroidal anti-inflammatory drug indomethacin on Clostridium difficile infection (CDI) severity.

MATERIALS & METHODS

Indomethacin was administered in two different mouse models of antibiotic-associated CDI in two different facilities, using a low and high dose of indomethacin.

RESULTS

Indomethacin administration caused weight loss, increased the signs of severe infection and worsened histopathological damage, leading to 100% mortality during CDI. Indomethacin-treated, antibiotic-exposed mice infected with C. difficile had enhanced intestinal inflammation with increased expression of KC, IL-1β and IL-22 compared with infected mice unexposed to indomethacin.

CONCLUSION

These results demonstrate a negative impact of nonsteroidal anti-inflammatory drugs on antibiotic-associated CDI in mice and suggest that targeting the synthesis or signaling of prostaglandins might be an approach to ameliorating the severity of CDI.

Use of a baseline risk score to identify the risk of serious infectious events in patients with rheumatoid arthritis during certolizumab pegol treatment

BACKGROUND

The risk of serious infectious events (SIEs) is increased in patients with rheumatoid arthritis (RA). The aim of this study was to develop an age-adjusted comorbidity index (AACI) to predict, using baseline characteristics, the SIE risk in patients with RA treated with certolizumab pegol (CZP).

METHODS

Data of CZP-treated patients with RA were pooled from the RAPID1/RAPID2 randomized controlled trials (RCT CZP) and their open-label extensions (All CZP). Predictors of the first SIE were examined using multivariate Cox models. The AACI was developed by assigning specific weights to patient age and comorbidities on the basis of relative SIE risk. SIE rates were predicted using AACI score and baseline glucocorticoid use, and they were compared with observed rates. The percentage of patients in each SIE risk group achieving low disease activity (LDA)/remission was examined at 1 year of treatment.

RESULTS

Among 1224 RCT CZP patients, 40 reported ≥ 1 SIE (incidence rate [IR] 5.09/100 patient-years [PY]), and 201 of 1506 All CZP patients reported ≥ 1 SIE (IR 3.66/100 PY). Age ≥ 70 years, diabetes mellitus, and chronic obstructive pulmonary disease/asthma made the greatest contributions to AACI score. SIE rates predicted using AACI and glucocorticoid use at baseline showed good agreement with observed SIE rates across low-risk and high-risk groups. At 1 year, more high-risk All CZP patients than low-risk All CZP patients reported SIEs (IR 8.4/100 PY vs. IR 3.4/100 PY). Rates of LDA/remission were similar between groups.

CONCLUSIONS

AACI and glucocorticoid use were strong baseline predictors of SIE risk in CZP-treated patients with RA. Predicted SIE risk was not associated with patients' likelihood of clinical response. This SIE risk score may provide a valuable tool for clinicians when considering the risk of infection in individual patients with RA.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00152386 (registered 7 September 2005); NCT00160602 (registered 8 September 2005); NCT00175877 (registered 9 September 2005); and NCT00160641 (registered 8 September 2005).

Identification of target risk groups for population-based Clostridium difficile infection prevention strategies using a population attributable risk approach

OBJECTIVES

We aimed to determine risk factors associated with Clostridium difficile infection (CDI) and assess the contributions of these factors on CDI burden.

METHODS

We conducted a 1:4 matched case-control study using a national claims dataset. Cases were incident CDI without a history of CDI in the previous 84 days, and were age- and sex-matched with control patients. We ascertained exposure, defined as a history of morbidities and drug use within 90 days. The population attributable risk (PAR) percent for risk factors was estimated using odds ratios (ORs) obtained from the case-control study.

RESULTS

Overall, the strongest CDI-associated risk factors, which have significant contributions to the CDI burden as well, were the experience of gastroenteritis (OR=5.08, PAR%=17.09%) and use of antibiotics (OR=1.69, PAR%=19.00%), followed by the experiences of female pelvic infection, irritable bowel syndrome, inflammatory bowel disease, and pneumonia, and use of proton-pump inhibitors (OR=1.52-2.37, PAR%=1.95-2.90).

CONCLUSIONS

The control of risk factors that had strong association with CDI and affected large proportions of total CDI cases would be beneficial for CDI prevention. We suggest performing CDI testing for symptomatic patients with gastroenteritis and implementing antibiotics stewardship.

Comparison of (R)-ketamine and lanicemine on depression-like phenotype and abnormal composition of gut microbiota in a social defeat stress model

Accumulating evidence suggests a key role of the gut–microbiota–brain axis in the antidepressant actions of certain compounds. Ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, showed rapid and sustained antidepressant effects in treatment-resistant depressed patients. In contrast, another NMDAR antagonist, lanicemine, did not exhibit antidepressant effects in such patients. (R)-ketamine, the (R)-enantiomer of ketamine, has rapid-acting and long-lasting antidepressant effects in rodent models of depression. Here we compared the effects of (R)-ketamine and lanicemine on depression-like phenotype and the composition of the gut microbiota in susceptible mice after chronic social defeat stress (CSDS). In behavioral tests, (R)-ketamine showed antidepressant effects in the susceptible mice, whereas lanicemine did not. The 16S ribosomal RNA gene sequencing of feces demonstrated that (R)-ketamine, but not lanicemine, significantly attenuated the altered levels of Bacteroidales, Clostridiales and Ruminococcaceae in the susceptible mice after CSDS. At the genus level, (R)-ketamine significantly attenuated the marked increase of Clostridium in the susceptible mice. In contrast, the effects of lanicemine were less potent than those of (R)-ketamine. This study suggests that the antidepressant effects of (R)-ketamine might be partly mediated by the restoration of altered compositions of the gut microbiota in a CSDS model.

Risk Factors for Community-Associated Clostridium difficile Infection in Adults: A Case-Control Study

BACKGROUND

An increasing proportion of Clostridium difficile infections (CDI) in the United States are community-associated (CA). We conducted a case-control study to identify CA-CDI risk factors.

METHODS

We enrolled participants from 10 US sites during October 2014-March 2015. Case patients were defined as persons age ≥18 years with a positive C. difficile specimen collected as an outpatient or within 3 days of hospitalization who had no admission to a health care facility in the prior 12 weeks and no prior CDI diagnosis. Each case patient was matched to one control (persons without CDI). Participants were interviewed about relevant exposures; multivariate conditional logistic regression was performed.

RESULTS

Of 226 pairs, 70.4% were female and 52.2% were ≥60 years old. More case patients than controls had prior outpatient health care (82.1% vs 57.9%; P < .0001) and antibiotic (62.2% vs 10.3%; P < .0001) exposures. In multivariate analysis, antibiotic exposure-that is, cephalosporin (adjusted matched odds ratio [AmOR], 19.02; 95% CI, 1.13-321.39), clindamycin (AmOR, 35.31; 95% CI, 4.01-311.14), fluoroquinolone (AmOR, 30.71; 95% CI, 2.77-340.05) and beta-lactam and/or beta-lactamase inhibitor combination (AmOR, 9.87; 95% CI, 2.76-340.05),-emergency department visit (AmOR, 17.37; 95% CI, 1.99-151.22), white race (AmOR 7.67; 95% CI, 2.34-25.20), cardiac disease (AmOR, 4.87; 95% CI, 1.20-19.80), chronic kidney disease (AmOR, 12.12; 95% CI, 1.24-118.89), and inflammatory bowel disease (AmOR, 5.13; 95% CI, 1.27-20.79) were associated with CA-CDI.

CONCLUSIONS

Antibiotics remain an important risk factor for CA-CDI, underscoring the importance of appropriate outpatient prescribing. Emergency departments might be an environmental source of CDI; further investigation of their contribution to CDI transmission is needed.

Treatment with high-dose antidepressants severely exacerbates the pathological outcome of experimental Escherichia coli infections in poultry

There is an urgent need for novel antibiotics as the current antibiotics are losing their value due to increased resistance among clinically important bacteria. Sertraline, an on-marked anti-depressive drug, has been shown to modify bacterial activity in vitro, including increasing the susceptibility of Escherichia coli to antibiotics. The aim of the present study was to investigate if the antimicrobial activity of sertraline could be documented under clinical settings, hereunder if sertraline could potentiate the effect of tetracycline in treatment of an experimentally induced ascending infection in poultry. A total of 40 chickens were divided in four groups of 10 chickens each. All chickens were challenged with 4x10³ colony forming units (CFU) of a tetracycline resistant E. coli strain using a surgical infection model, and subsequently treated with either high-dose sertraline, tetracycline, a combination hereof or received no treatment. Seven days post challenge all birds were submitted to necropsy and scored pathologically for lesions. The average lesion scores were significantly higher (P<0.05) in the groups that were treated with high-dose sertraline or high-dose sertraline combined with tetracycline. In conclusion high-dose treatments (four times the maximum therapeutic dose for treating human depression) with sertraline as an adjuvant for treatment of antibiotic resistant E. coli infections exacerbate the pathological outcome of infection in chickens.

Antidepressants, antimicrobials or both? Gut microbiota dysbiosis in depression and possible implications of the antimicrobial effects of antidepressant drugs for antidepressant effectiveness

OBJECTIVES

The first drug repurposed for the treatment of depression was the tuberculostatic iproniazid. At present, drugs belonging to new classes of antidepressants still have antimicrobial effects. Dysbiosis of gut microbiota was implicated in the development or exacerbation of mental disorders, such as major depressive disorder (MDD). Based on the current interest in the gut-brain axis, the focus of this narrative review is to compile the available studies regarding the influences of gut microbiota in behavior and depression and to show the antimicrobial effect of antidepressant drugs. A discussion regarding the possible contribution of the antimicrobial effect of antidepressant drugs to its effectiveness/resistance is included.

METHODS

The search included relevant articles from PubMed, SciELO, LILACS, PsycINFO, and ISI Web of Knowledge.

RESULTS

MDD is associated with changes in gut permeability and microbiota composition. In this respect, antidepressant drugs present antimicrobial effects that could also be related to the effectiveness of these drugs for MDD treatment. Conversely, some antimicrobials present antidepressant effects.

CONCLUSION

Both antidepressants and antimicrobials present neuroprotective/antidepressant and antimicrobial effects. Further studies are needed to evaluate the participation of antimicrobial mechanisms of antidepressants in MDD treatment as well as to determine the contribution of this effect to antidepressant resistance.

The Association between GABA-Modulators and Clostridium difficile Infection - A Matched Retrospective Case-Control Study

OBJECTIVE

Recently, metabolomics studies have suggested that the neurotransmitter γ-amino butyric acid (GABA) may modulate C. difficile infection (CDI) pathogenesis. In the present study, we investigated the association between GABA-modulating pharmaceuticals and CDI development.

METHODS

In July-December 2013, we performed a matched, retrospective case-control study in Skåne county, Sweden, to assess the association between the use of GABA-modulators (defined as regular use of at least one of the following: zolpidem, zopiclone, benzodiazepines, gabapentin, pregabalin or baclofen) and CDI. Multivariate regression models, adjusted for known risk factors for CDI, were fitted to assess the associations and a propensity score-adjusted analysis was performed.

RESULTS

The study included 292 cases and 292 matched controls. In a multivariate regression model only recent antibiotic use (clindamycin, cephalosporins and fluoroquinolones) and nursing home residency was significantly associated with CDI. The regular use of any GABA-modulator was not associated with CDI (OR = 1.07, 95%CI 0.69-1.66, p = 0.76). The association between regular use of the selective GABA-agonist zolpidem and CDI trended towards significance (OR = 2.31, 95%CI 0.91-5.86, p = 0.078). These associations remained when only cases treated with antibiotics were included. Corresponding findings for zolpidem was observed in a propensity-score adjusted analysis (OR = 2.52, 95% CI 0.91-6.97, p = 0.075). Severe initial CDI was significantly associated with CDI recurrence (OR = 3.77, 95% CU 1.20-11.86, p = 0.023).

CONCLUSION

This study did not identify a general association between GABA-modulators and CDI. A trend towards a significant association between zolpidem and CDI was observed, an association that should be re-assessed in a study appropriately powered for this particular hypothesis.

Prevotella and Klebsiella proportions in fecal microbial communities are potential characteristic parameters for patients with major depressive disorder

BACKGROUND

The diagnosis of major depression disorder (MDD) and other mental disorders were depended on some subjective survey scales. There are confirmed relationship between the gut flora and the mental states of MDD patients.

METHODS

The V3-V4 region of the 16S rRNA gene was extracted from the fecal microbial communities in MDD patients, PCR amplified and sequenced on the Illumina Miseq platform.

RESULTS

More phylum Firmicutes, less Bacteroidetes, and more genus Prevotella, Klebsiella, Streptococcus and Clostridium XI were found in MDD patients. The changes of the proportion of Prevotella and Klebsiella were consistent with Hamilton depression rating scale.

LIMITATIONS

The conclusion was limited by small sample sizes and potential uncontrollable influence factors on fecal microbiota.

DISCUSSION

Prevotella and Klebsiella proportion in fecal microbial communities should be concerned in the diagnosis and therapeutic monitoring of MDD in future.