Clostridium difficile infection: new approaches to prevention, non-antimicrobial treatment, and stewardship

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.

Antimicrobial Activity of Some Steroidal Hydrazones

Twelve steroid based hydrazones were in silico evaluated using computer program PASS as antimicrobial agents. The experimental evaluation revealed that all compounds have low to moderate antibacterial activity against all bacteria tested, except for B. cereus with MIC at a range of 0.37-3.00 mg/mL and MBC at 0.75-6.00 mg/mL. The most potent appeared to be compound 11 with MIC/MBC of 0.75/1.5 mg/mL, respectively. The evaluation of antibacterial activity against three resistant strains MRSA, E. coli and P. aeruginosa demonstrated superior activity of compounds against MRSA compared with ampicillin, which did not show bacteriostatic or bactericidal activities. All compounds exhibited good antifungal activity with MIC of 0.37-1.50 mg/mL and MFC of 1.50-3.00 mg/mL, but with different sensitivity against fungi tested. According to docking studies, 14-alpha demethylase inhibition may be responsible for antifungal activity. Two compounds were evaluated for their antibiofilm activity. Finally, drug-likeness and docking prediction were performed.

Toxic Megacolon Burdened with COVID-19 Coinfection-Worsening of an Unfavorable Diagnosis: A Single-Center Retrospective Study

INTRODUCTION

This study primarily sought to evaluate the risk factors for toxic megacolon development and treatment outcomes in Clostridium difficile-positive COVID-19 patients, secondarily to determining predictors of survival.

METHODS

During the second COVID-19 wave (May 2020 to May 2021), we identified 645 patients with confirmed COVID-19 infection, including 160 patients with a severe course in the intensive care unit. We selected patients with Clostridium difficile infection (CDI) (31 patients) and patients with toxic megacolon (9 patients) and analyzed possible risk factors.

RESULTS

Patients who developed toxic megacolon had a higher incidence (without statistical significance, due to small sample size) of cancer and chronic obstructive pulmonary disease, a higher proportion of them required antibiotic treatment using cephalosporins or penicillins, and there was a higher rate of extracorporeal circulation usage. C-reactive protein (CRP) and interleukin-6 values showed significant differences between the groups (CRP [median 126 mg/L in the non-toxic megacolon cohort and 237 mg/L in the toxic megacolon cohort; p = 0.037] and interleukin-6 [median 252 ng/L in the group without toxic megacolon and 1127 ng/L in those with toxic megacolon; p = 0.016]). As possible predictors of survival, age, presence of chronic venous insufficiency, cardiac disease, mechanical ventilation, and infection with Candida species were significant for increasing the risk of death, while corticosteroid and cephalosporin treatment and current Klebsiella infection decreased this risk.

CONCLUSIONS

More than ever, the COVID-19 pandemic required strong up-to-date treatment recommendations to decrease the rate of serious in-hospital complications. Further studies are required to evaluate the interplay between COVID-19 and CDI/toxic megacolon.

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.

The burden of Clostridioides difficile infection in COVID-19 patients: A systematic review and meta-analysis

OBJECTIVES

The main aim of this systematic review and meta-analysis was to assess the proportion of confirmed COVID-19 patients with Clostridioides difficile infection (CDI) and to describe risk factors and outcome of these patients.

METHODS

MEDLINE and Cochrane Central Register of Controlled Trials databases were searched up to July 15, 2021. We included studies reporting data on CDI occurring in patients with a confirmed diagnosis of COVID-19. We pooled proportion of CDI patients using a random effects model (DerSimonian-Laird method) stabilising the variances using the Freeman-Tukey double arcsine transformation.

RESULTS

Thirteen studies were included in the systematic review. All the studies retrospectively collected data between February 2020 and February 2021. The reported CDI incidence rates ranged from 1.4 to 4.4 CDI cases per 10,000 patient-days. Seven studies reported data on the number of COVID-19 patients who developed CDI and the total number of COVID-19 patients in the study period and were included in the meta-analysis, comprising 23,697 COVID-19 patients. The overall pooled proportion of COVID-19 patients who had CDI was 1% [95% confidence interval: 1-2]. Among studies reporting CDI occurrence in patients with and without COVID-19, the majority of them reported reduced or unchanged CDI rates compared to pre-COVID period.

CONCLUSIONS

CDI is a relevant issue for COVID-19 patients. Adherence to infection prevention and control measures and to the antimicrobial stewardship principles is crucial even during the COVID-19 pandemic.

Novel Thiazole-Based Thiazolidinones as Potent Anti-infective Agents: In silico PASS and Toxicity Prediction, Synthesis, Biological Evaluation and Molecular Modelling

AIMS AND OBJECTIVE

The infectious disease treatment remains a challenging concern owing to the increasing number of pathogenic microorganisms associated with resistance to multiple drugs. A promising approach for combating microbial infection is to combine two or more known bioactive heterocyclic pharmacophores in one molecular platform. Herein, the synthesis and biological evaluation of novel thiazole-thiazolidinone hybrids as potential antimicrobial agents were dissimilated.

MATERIALS AND METHODS

The preparation of the substituted 5-benzylidene-2-thiazolyimino-4- thiazolidinones was achieved in three steps from 2-amino-5-methylthiazoline. All the compounds have been screened in PASS antibacterial activity prediction and in a panel of bacteria and fungi strains. Minimum inhibitory concentration and minimum bacterial concentration were both determined by microdilution assays. Molecular modeling was conducted using Accelrys Discovery Studio 4.0 client. ToxPredict (OPEN TOX) and ProTox were used to estimate the toxicity of the title compounds.

RESULTS

PASS prediction revealed the potentiality antibacterial property of the designed thiazolethiazolidinone hybrids. All tested compounds were found to kill and to inhibit the growth of a vast variety of bacteria and fungi, and were more potent than the commercial drugs, streptomycin, ampicillin, bifomazole and ketoconazole. Further, in silico study was carried out for prospective molecular target identification and revealed favorable interaction with the target enzymes E. coli MurB and CYP51B of Aspergillus fumigatus. Toxicity prediction revealed that none of the active compounds was found toxic.

CONCLUSION

Substituted 5-benzylidene-2-thiazolyimino-4-thiazolidinones, endowing remarkable antibacterial and antifungal properties, were identified as a novel class of antimicrobial agents and may find a potential therapeutic use to eradicate infectious diseases.

The Burden of Clostridioides Difficile Infection during the COVID-19 Pandemic: A Retrospective Case-Control Study in Italian Hospitals (CloVid)

Data on the burden of Clostridioides difficile infection (CDI) in Coronavirus Disease 2019 (COVID-19) patients are scant. We conducted an observational, retrospective, multicenter, 1:3 case (COVID-19 patients with CDI)-control (COVID-19 patients without CDI) study in Italy to assess incidence and outcomes, and to identify risk factors for CDI in COVID-19 patients. From February through July 2020, 8402 COVID-19 patients were admitted to eight Italian hospitals; 38 CDI cases were identified, including 32 hospital-onset-CDI (HO-CDI) and 6 community-onset, healthcare-associated-CDI (CO-HCA-CDI). HO-CDI incidence was 4.4 × 10,000 patient-days. The percentage of cases recovering without complications at discharge (i.e., pressure ulcers, chronic heart decompensation) was lower than among controls (p = 0.01); in-hospital stays was longer among cases, 35.0 versus 19.4 days (p = 0.0007). The presence of a previous hospitalisation (p = 0.001), previous steroid administration (p = 0.008) and the administration of antibiotics during the stay (p = 0.004) were risk factors associated with CDI. In conclusions, CDI complicates COVID-19, mainly in patients with co-morbidities and previous healthcare exposures. Its association with antibiotic usage and hospital acquired bacterial infections should lead to strengthen antimicrobial stewardship programmes and infection prevention and control activities.

[Results of the Program for the Rational Use of Antimicrobials in a Mexican hospital, 2013-2018Resultados de um programa para o uso racional de antimicrobianos num hospital no México, 2013-2018]

Objetivo.

Describir los resultados del Programa de Uso Racional de Antimicrobianos en el Hospital Juárez de México.

Métodos.

Se diseñó un estudio de tipo observacional, transversal, retrospectivo y descriptivo. Se analizó el consumo de antimicrobianos de enero de 2013 a diciembre de 2018 a través del cálculo de la dosis diaria definida (DDD); para el análisis de costos se realizó un cálculo de costeo tradicional.

Resultados.

En el grupo de los carbapenémicos, es notable la reducción en el consumo de imipenem/cilastina: se pasó de una DDD en el 2013 de 2,3 a 0,7 en el 2018, con una reducción de 70%. En cambio, en los otros dos fármacos, se ha observado un incremento. En meropenem se registró de 2% (de 2,4 en 2013 a 2,5 en 2018); en el consumo de ertapenem el incremento es de 75% (de 1 en 2013 a 1,8 en 2018). En total, el gasto de antimicrobianos durante 2013 fue de $930 556,46, mientras que en 2018 fue de $856 079,10, con una diferencia de 8%, lo que equivale a $74 905,61 del gasto total (los valores se expresan en dólares estadounidenses).

Conclusiones.

Se necesita evaluar de manera constante los programas para el uso racional de antimicrobianos, mediante el monitoreo del consumo y el gasto derivado.

Clinical impact of a Clostridioides (Clostridium) difficile bedside infectious disease stewardship intervention

Objectives

To evaluate the clinical impact of a bedside visit to patients with a positive Clostridioides difficile test on the antimicrobial stewardship of C. difficile infection (CDI) and non-C. difficile infections.

Methods

All patients ≥18 years old with positive CDI laboratory tests hospitalized between January 2017 and August 2017 received an immediate bedside intervention that consisted mainly of checking protective measures and providing recommendations on infection control and the management of CDI and other infections.

Results

A total of 214 patients were evaluated. The infectious disease (ID) physician was the first to establish protective measures in 25.2% of the cases. In 22/29 (75.9%) cases, physicians in charge accepted ID consultant recommendations to stop CDI treatment in asymptomatic patients. Unnecessary non-CDI antibiotics were discontinued in 19.1% of the cases. ID recommendations were not accepted by physicians in charge in only 12.6% of the cases.

Conclusions

A bedside rapid intervention for patients with a CDI-positive faecal sample was effective in avoiding overdiagnosis and unnecessary antibiotic treatment, optimizing anti-CDI drugs, increasing compliance with infection control measures and providing educational advice.

Heterocycle Compounds with Antimicrobial Activity

Background:

Bacterial infections are a growing problem worldwide causing morbidity and mortality mainly in developing countries. Moreover, the increased number of microorganisms, developing multiple resistances to known drugs, due to abuse of antibiotics, is another serious problem. This problem becomes more serious for immunocompromised patients and those who are often disposed to opportunistic fungal infections.

Objective:

The objective of this manuscript is to give an overview of new findings in the field of antimicrobial agents among five-membered heterocyclic compounds. These heterocyclic compounds especially five-membered attracted the interest of the scientific community not only for their occurrence in nature but also due to their wide range of biological activities.

Method:

To reach our goal, a literature survey that covers the last decade was performed.

Results:

As a result, recent data on the biological activity of thiazole, thiazolidinone, benzothiazole and thiadiazole derivatives are mentioned.

Conclusion:

It should be mentioned that despite the progress in the development of new antimicrobial agents, there is still room for new findings. Thus, research still continues.

Treatment Options for Colistin Resistant Klebsiella pneumoniae: Present and Future

Multidrug-resistant (MDR) Klebsiella pneumoniae represents an increasing threat to human health, causing difficult-to-treat infections with a high mortality rate. Since colistin is one of the few treatment options for carbapenem-resistant K. pneumoniae infections, colistin resistance represents a challenge due to the limited range of potentially available effective antimicrobials, including tigecycline, gentamicin, fosfomycin and ceftazidime/avibactam. Moreover, the choice of these antimicrobials depends on their pharmacokinetics/pharmacodynamics properties, the site of infection and the susceptibility profile of the isolated strain, and is sometimes hampered by side effects. This review describes the features of colistin resistance in K. pneumoniae and the characteristics of the currently available antimicrobials for colistin-resistant MDR K. pneumoniae, as well as the characteristics of novel antimicrobial options, such as the soon-to-be commercially available plazomicin and cefiderocol. Finally, we consider the future use of innovative therapeutic strategies in development, including bacteriophages therapy and monoclonal antibodies.

Recurrent Clostridium difficile Infection: Risk Factors, Treatment, and Prevention

The most common cause of antibiotic-associated diarrhea is Clostridium difficile infection (CDI). Recurrent C. difficile infection (rCDI) often occurs after successful treatment of CDI. Due to the increased incidence and the difficulty in treating rCDI, it is becoming an important clinical issue. Identifying risk factors is helpful for early detection, treatment, and prevention of rCDI. Advanced age, use of antibiotics, gastric acid suppression, and infection with a hypervirulent strain are currently regarded as the major risk factors for rCDI. Several treatment modalities, including vancomycin, fidaxomicin, and fecal microbiota transplant (FMT), are suggested for rCDI treatment. However, there is currently no definitive treatment method with sufficient evidence for rCDI. Recent studies have focused on FMT and have shown positive results for rCDI. Prevention of rCDI by measures such as hand washing and isolation of patients is very important. However, these preventive measures are often overlooked in clinical practice. Here, we review the risk factors, treatment, and prevention of rCDI.

Novel antimicrobial agents' discovery among the steroid derivatives

Fourteen steroid compounds were in silico evaluated using computer program PASS as antimicrobial agents. The experimental studies evaluation revealed that all compounds have good antibacterial activity with MIC at range of 0.003-0.96 mg/mL and MBC 0.06-1.92 mg/mL. Almost all compounds except of compound 4 (3β-acetoxy-1^/-p-chlorophenyl-3^/-methyl-5α-androstano[17,16-d]pyrazoline) were more potent than Ampicillin, and they were equipotent or more potent than Streptomycine. All compounds exhibited good antifungal activity with MIC at 0.003-0.96 mg/mL and MFC at 0.006-1.92 mg/mL but with different sensitivity against fungi tested. According to docking studies 14-alpha demethylase inhibition may be responsible for antifungal activity. Prediction of toxicity by PROTOX and GUSAR revealed that compounds have low toxicity and can be considered as potential lead compounds for the further studies.

5-Adamantan thiadiazole-based thiazolidinones as antimicrobial agents. Design, synthesis, molecular docking and evaluation

In continuation of our efforts to develop new compounds with antimicrobial properties we describe design, synthesis, molecular docking study and evaluation of antimicrobial activity of seventeen novel 2-{[5-(adamantan-1-yl)-1,3,4-thiadiazol-2-yl]-imino}-5-arylidene-1,3-thiazolidin-4-ones. All compounds showed antibacterial activity against eight Gram positive and Gram negative bacterial species. Twelve out of seventeen compounds were more potent than streptomycin and all compounds exhibited higher potency than ampicillin. Compounds were also tested against three resistant bacterial strains: MRSA, P. aeruginosa and E. coli. The best antibacterial potential against ATCC and resistant strains was observed for compound 8 (2-{[5-(adamantan-1-yl)-1,3,4-thiadiazol-2-yl]-imino}-5-(4-nitrobenzylidene)-1,3thiazolidin-4-one). The most sensitive bacterium appeared to be S. typhimirium, followed by B. cereus while L. monocitogenes and M. flavus were the most resistant. Compounds were also tested for their antifungal activity against eight fungal species. All compounds exhibited antifungal activity better than the reference drugs bifonazole and ketokonazole (3-115 times). It was found that compound 8 appeared again to be the most potent. Molecular docking studies on E. coli MurB, MurA as well as C. albicans CYP 51 and dihydrofolate reductase were used for the prediction of mechanism of antibacterial and antifungal activities confirming the experimental results.

Novel Antimicrobials for the Treatment of Clostridium difficile Infection

The current picture of Clostridium difficile infection (CDI) is alarming with a mortality rate ranging between 3% and 15% and a CDI recurrence rate ranging from 12% to 40%. Despite the great efforts made over the past 10 years to face the CDI burden, there are still gray areas in our knowledge on CDI management. The traditional anti-CDI antimicrobials are not always adequate in addressing the current needs in CDI management. The aim of our review is to give an update on novel antimicrobials for the treatment of CDI, considering the currently available evidences on their efficacy, safety, molecular mechanism of action, and their probability to be successfully introduced into the clinical practice in the near future. We identified, through a PubMed search, 16 novel antimicrobial molecules under study for CDI treatment: cadazolid, surotomycin, ridinilazole, LFF571, ramoplanin, CRS3123, fusidic acid, nitazoxanide, rifampin, rifaximin, tigecycline, auranofin, NVB302, thuricin CD, lacticin 3147, and acyldepsipeptide antimicrobials. In comparison with the traditional anti-CDI antimicrobial treatment, some of the novel antimicrobials reviewed in this study offer several advantages, i.e., the favorable pharmacokinetic and pharmacodynamic profile, the narrow-spectrum activity against CD that implicates a low impact on the gut microbiota composition, the inhibitory activity on CD sporulation and toxins production. Among these novel antimicrobials, the most active compounds in reducing spore production are cadazolid, ridinilazole, CRS3123, ramoplanin and, potentially, the acyldepsipeptide antimicrobials. These antimicrobials may potentially reduce CD environment spread and persistence, thus reducing CDI healthcare-associated acquisition. However, some of them, i.e., surotomycin, fusidic acid, etc., will not be available due to lack of superiority versus standard of treatment. The most CD narrow-spectrum novel antimicrobials that allow to preserve microbiota integrity are cadazolid, ridinilazole, auranofin, and thuricin CD. In conclusion, the novel antimicrobial molecules under development for CDI have promising key features and advancements in comparison to the traditional anti-CDI antimicrobials. In the near future, some of these new molecules might be effective alternatives to fight CDI.