Clinical characteristics and risk factors of enterococcal infections in Nagasaki, Japan: a retrospective study

Characteristics and outcomes of urinary tract infections caused by Enterococci: A multicenter retrospective study from two tertiary hospitals in Saudi Arabia

Enterococci are Gram-positive coccus bacteria that are normally present in the gastrointestinal tract and ordinarily function commensally with humans. Very few studies have investigated the characteristics of enterococcal infections. We aimed to characterize patients with urinary tract infections (UTIs) due to Enterococci and their outcomes. This was a retrospective cohort study between June 2012-November 2022. Patients who had clinically and microbiologically confirmed Enterococcal UTI based on a urine culture positive for E. faecalis or E. faecium with a count of ≥105 CFU/mL and having urinary tract symptoms were included. A total of 396 patients were eligible and included. The patients had a median age of 61 years and were mostly females (56.8 %). The most common characteristics were hospitalization in a non-ICU ward, having a urinary catheter, and recent use of antibiotics within the last 3 months (66.4 %, 59.3 %, and 51.8 %, respectively). Infection with E. faecalis was more common than E. faecium (77.3 % vs. 22.7 %). However, the latter exhibited higher rates of antibiotic resistance (P < 0.001 to several antibiotics) and was associated with significantly higher median C-reactive protein level (26.7 vs. 13 mg/dL; P = 0.025), mortality (23 % vs. 10.1 %; P = 0.002), and median length of stay (25 vs. 11.5 days; P < 0.001). We found that most patients with enterococcal UTIs had a history of having a urinary catheter and recent antibiotic use and were mostly females and hospitalized in non-ICU wards. E. faecium-infected patients experienced more severe episodes and poorer outcomes compared to patients infected with E. faecalis; thus, would need more aggressive therapy.

Characteristics of Enterococcus species bloodstream infections among adults with and without onco-hematological malignancies: Experiences from the national center of Hungary

Introduction

Over the past decade, enterococcal bloodstream infection (BSI) shows increasing incidence globally among the elderly and in patients with comorbidities. In this study, we aimed to assess microbiological and clinical characteristics and long-term outcomes of BSIs caused by Enterococcus spp. in adult patients with and without active onco-hematological malignancies hospitalized at a national referral institute.

Methods

A prospective analysis of consecutive enterococcal BSI cases was conducted in the National Institute of Hematology and Infectious Diseases (Budapest, Hungary) between December 2019 and April 2022. We compared characteristics and outcomes at 30-days and 1 year after diagnosis among patients with and without onco-hematological malignancies.

Results

In total, 141 patients were included (median age 68 ± 21 years, female sex 36.9%), 37% (52/141) had active onco-hematological malignancies. The distribution of species was as follows: 50.4% Enterococcus faecalis, 46.1% Enterococcus faecium, 1.4% Enterococcus avium and Enterococcus gallinarum, and 0.7% Enterococcus raffinosus. No statistically significant differences in all-cause mortality rates were observed between patient subgroups at 30 days (32.7 vs. 28.1%; P = 0.57) and 1 year (75.0 vs. 60.7%; P = 0.09).

Conclusion

Enterococcal bloodstream infections yielded a relevant burden of morbidity, but with no statistical difference in long-term outcomes of adult patients with and without active onco-hematological malignancies.

From the Friend to the Foe-Enterococcus faecalis Diverse Impact on the Human Immune System

Enterococcus faecalis is a bacterium which accompanies us from the first days of our life. As a commensal it produces vitamins, metabolizes nutrients, and maintains intestinal pH. All of that happens in exchange for a niche to inhabit. It is not surprising then, that the bacterium was and is used as an element of many probiotics and its positive impact on the human immune system and the body in general is hard to ignore. This bacterium has also a dark side though. The plasticity and relative ease with which one acquires virulence traits, and the ability to hide from or even deceive and use the immune system to spread throughout the body make E. faecalis a more and more dangerous opponent. The statistics clearly show its increasing role, especially in the case of nosocomial infections. Here we present the summarization of current knowledge about E. faecalis, especially in the context of its relations with the human immune system.

Comparative pangenome analysis of Enterococcus faecium and Enterococcus lactis provides new insights into the adaptive evolution by horizontal gene acquisitions

BACKGROUND

Enterococcus faecium and E. lactis are phylogenetically closely related lactic acid bacteria that are ubiquitous in nature and are known to be beneficial or pathogenic. Despite their considerable industrial and clinical importance, comprehensive studies on their evolutionary relationships and genomic, metabolic, and pathogenic traits are still lacking. Therefore, we conducted comparative pangenome analyses using all available dereplicated genomes of these species.

RESULTS

E. faecium was divided into two subclades: subclade I, comprising strains derived from humans, animals, and food, and the more recent phylogenetic subclade II, consisting exclusively of human-derived strains. In contrast, E. lactis strains, isolated from diverse sources including foods, humans, animals, and the environment, did not display distinct clustering based on their isolation sources. Despite having similar metabolic features, noticeable genomic differences were observed between E. faecium subclades I and II, as well as E. lactis. Notably, E. faecium subclade II strains exhibited significantly larger genome sizes and higher gene counts compared to both E. faecium subclade I and E. lactis strains. Furthermore, they carried a higher abundance of antibiotic resistance, virulence, bacteriocin, and mobile element genes. Phylogenetic analysis of antibiotic resistance and virulence genes suggests that E. faecium subclade II strains likely acquired these genes through horizontal gene transfer, facilitating their effective adaptation in response to antibiotic use in humans.

CONCLUSIONS

Our study offers valuable insights into the adaptive evolution of E. faecium strains, enabling their survival as pathogens in the human environment through horizontal gene acquisitions.

Niosome as an Effective Nanoscale Solution for the Treatment of Microbial Infections

Numerous disorders go untreated owing to a lack of a suitable drug delivery technology or an appropriate therapeutic moiety, particularly when toxicities and side effects are a major concern. Treatment options for microbiological infections are not fulfilled owing to significant adverse effects or extended therapeutic options. Advanced therapy options, such as active targeting, may be preferable to traditional ways of treating infectious diseases. Niosomes can be defined as microscopic lamellar molecules formed by a mixture of cholesterol, nonionic surfactants (alkyl or dialkyl polyglycerol ethers), and sometimes charge-inducing agents. These molecules comprise both hydrophilic and hydrophobic moieties of varying solubilities. In this review, several pathogenic microbes such as Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Plasmodium, Leishmania, and Candida spp. have been evaluated. Also, the development of a proper niosomal formulation for the required application was discussed. This review also reviews that an optimal formulation is dependent on several aspects, including the choice of nonionic surfactant, fabrication process, and fabrication parameters. Finally, this review will give information on the effectiveness of niosomes in treating acute microbial infections, the mechanism of action of niosomes in combating microbial pathogens, and the advantages of using niosomes over other treatment modalities.

A Comprehensive Review of Bioactive Compounds from Lactic Acid Bacteria: Potential Functions as Functional Food in Dietetics and the Food Industry

Lactic acid bacteria (LAB) are beneficial microbes known for their health-promoting properties. LAB are well known for their ability to produce substantial amounts of bioactive compounds during fermentation. Peptides, exopolysaccharides (EPS), bacteriocins, some amylase, protease, lipase enzymes, and lactic acid are the most important bioactive compounds generated by LAB activity during fermentation. Additionally, the product produced by LAB is dependent on the type of fermentation used. LAB derived from the genera Lactobacillus and Enterococcus are the most popular probiotics at present. Consuming fermented foods has been previously connected to a number of health-promoting benefits such as antibacterial activity and immune system modulation. Furthermore, functional food implementations lead to the application of LAB in therapeutic nutrition such as prebiotic, immunomodulatory, antioxidant, anti-tumor, blood glucose lowering actions. Understanding the characteristics of LAB in diverse sources and its potential as a functional food is crucial for therapeutic applications. This review presents an overview of functional food knowledge regarding interactions between LAB isolated from dairy products (dairy LAB) and fermented foods, as well as the prospect of functioning LAB in human health. Finally, the health advantages of LAB bioactive compounds are emphasized.

Ampicillin and Ceftobiprole Combination for the Treatment of Enterococcus faecalis Invasive Infections: "The Times They Are A-Changin"

BACKGROUND

Enterococcus faecalis is responsible for a large variety of severe infections. This study is a case series reporting our experience in the treatment of E. faecalis invasive infections with ampicillin in combination with ceftobiprole (ABPR).

METHODS

We retrospectively analyzed all the medical records of patients admitted to the University Hospital of Udine from January to December 2020 with a diagnosis of infective endocarditis or primary or non-primary complicated or uncomplicated bacteremia caused by E. faecalis.

RESULTS

Twenty-one patients were included in the final analysis. The clinical success rate was very high, accounting for 81% of patients, and microbiological cure was obtained in 86% of patients. One relapse was recorded in one patient who did not adhere to the partial oral treatment prescribed. Therapeutic drug monitoring (TDM) was always performed for ampicillin and ceftobiprole, and serum concentrations of both drugs were compared to the MICs of the different enterococcal isolates.

CONCLUSIONS

ABPR is a well-tolerated antimicrobial regimen with anti-E. faecalis activity. TDM can help clinicians optimize medical treatments to achieve the best possible efficacy with fewer side effects. ABPR might be a reasonable option for the treatment of severe invasive infections caused by E. faecalis due to the high level of enterococcal penicillin-binding protein (PBP) saturation.

Barriers to genetic manipulation of Enterococci: Current Approaches and Future Directions

Enterococcus faecalis and Enterococcus faecium are Gram-positive commensal gut bacteria that can also cause fatal infections. To study clinically relevant multi-drug resistant E. faecalis and E. faecium strains, methods are needed to overcome physical (thick cell wall) and enzymatic barriers that limit the transfer of foreign DNA and thus prevent facile genetic manipulation. Enzymatic barriers to DNA uptake identified in E. faecalis and E. faecium include type I, II and IV restriction modification systems and CRISPR-Cas. This review examines E. faecalis and E. faecium DNA defence systems and the methods with potential to overcome these barriers. DNA defence system bypass will allow the application of innovative genetic techniques to expedite molecular-level understanding of these important, but somewhat neglected, pathogens.

Cloning and sequencing of lsaE efflux pump gene from MDR Enterococci and its role in erythromycin resistance

Enterococci are opportunistic members of intestinal microbiota with notable ability to transmit antimicrobial resistance genes. Among the different resistance mechanisms, multidrug efflux is evolving as a huge problem in conferring multidrug resistance to bacterial cells because these pumps extrude a broad range of antimicrobials. Therefore, the aim of this work was to evaluate role of efflux pumps in the development of multi-drug resistance in Enterococci through studying the antimicrobial resistance profiles of Enterococci isolates, phenotypically and genotypically investigating the role of active efflux pumps in development of resistance, in addition to characterizing the most common efflux pump genes. The study involved the recovery of 149 Enterococci isolates from specimens of patients suffering infections in some hospitals in Egypt. Antimicrobial resistance profiles of isolates showed that only 1.3% of the isolates were resistant to each of linezolid, daptomycin, and fosfomycin. The highest resistance was to ampicillin (60.4%) while 47 of the isolates (31.54%) were found to be multidrug-resistant. Efflux pumps have shown to have a significant role in erythromycin resistance in 11 isolates (23.4% of MDR isolates) as indicated by an 8 or more fold decrease in minimum inhibitory concentration in the presence of the efflux pump inhibitor, carbonyl cyanide m- chlorophenylhydrazone (CCCP). End point PCR was used to detect efflux pump genes lsaE, msrC, and mefA in the 11 isolates at which efflux pumps were found to play a significant role in resistance. Nine out of the 11 isolates (81.8%) were found to carry lsaE gene. This gene was inserted into pUC21 vector and cloned into DH5α E. coli resulting in successful transformation and expression of erythromycin resistance in this host. Finally, sequencing of the lsaE gene was carried out. To the best of our knowledge, this is the first report on the cloning of lsaE gene from MDR Enterococcus isolates.

Risk Factors for Enterococcal Intra-Abdominal Infections and Outcomes in Intensive Care Unit Patients

Background: To investigate the risk factors for enterococcal intra-abdominal infections (EIAIs) and the association between EIAIs and outcomes in intensive care unit (ICU) patients. Methods: We reviewed retrospectively the records of patients with intra-abdominal infections admitted to the Department of Critical Care Medicine at Nanfang Hospital, Southern Medical University, China, from January 2011 to December 2018. Patients with intra-abdominal infections were divided into enterococcal and non-enterococcal groups based on whether enterococci were isolated from intra-abdominal specimens. Results: A total of 431 patients with intra-abdominal infections were included, of whom 119 were infected with enterococci and 312 were infected with non-enterococci. Enterococci were isolated in 27.6% of patients, accounting for 24.5% (129/527) of all clinical bacterial isolates. Post-operative abdominal infection (adjusted odds ratio [OR], 2.361; p = 0.004), intestinal infection (adjusted OR, 2.703; p < 0.001), Mannheim Peritonitis Index score (MPI; adjusted OR, 1.052; p = 0.015), and use of antibiotic agents within the previous 90 days (adjusted OR, 1.880; p = 0.025) were associated with an increased risk of EIAIs. Compared with patients without enterococcal infection, ICU patients with enterococcal infection had a higher risk of failure of initial clinical therapy (49.6% vs. 24.2%; p < 0.001) and longer hospital stays (33 days [19, 48] vs. 18 days [12, 29]; p < 0.001). Enterococcal infection was associated with increased 28-day mortality, in-hospital mortality, and ICU mortality. However, no difference was found in length of ICU stay between the two groups. Additionally, there was no difference in ICU mortality, hospital mortality, or 28-day mortality in patients infected with enterococcus who did or did not receive empirical anti-enterococcal therapy. Conclusion: Post-operative abdominal infection, intestinal infection, MPI score, and use of antibiotic agents within the previous 90 days were independent risk factors for enterococcal infection. Enterococcal infection was associated with reduced short-term survival in ICU patients.

Enterococcal bacteraemia 'silent but deadly': a population-based cohort study

BACKGROUND

The high mortality rate of patients with enterococcal infections has been shown to be associated with the severity of underlying comorbidities.

AIMS

To characterise the epidemiology, clinical characteristics, outcomes and predictors of mortality in patients with enterococcal bacteraemia.

METHODS

This was a retrospective cohort study of all enterococcal bacteraemia episodes in the Barwon region between January 2010 and March 2017. We assessed the epidemiology, clinical characteristics, outcomes and predictors of mortality using descriptive statistics and simple and multiple logistic regression analyses.

RESULTS

The incidence of enterococcal bacteraemia was 19.9/100 000 person-years. Males comprised 68.4%, and the median age was 71 years. Common comorbidities were gastrointestinal tract disease, urological disease, malignancies and cardiovascular disease. Infective endocarditis was observed in 15% of patients, and 1 of 27 also had colorectal cancer. Twelve patients referred for colonoscopy demonstrated previously undiagnosed colorectal neoplasia in 75% of these cases. The 30-day and 1-year mortality rates were 11.7 and 40.2% respectively. Sixty-nine cases with vancomycin-resistant Enterococcus were observed. Multiple logistic regression suggested that the presence of underlying urological malignancy (adjusted odds ratio = 3.57, 95% confidence intervals = 1.10-11.65, P = 0.035) and colorectal cancer (adjusted odds ratio = 4.47, 95% confidence intervals = 1.36-14.66, P = 0.014) were significant predictors of 1-year mortality.

CONCLUSIONS

Microbiological cure was inversely associated with 30-day mortality. The presence of underlying urological and colorectal malignancy was a predictor of 1-year mortality. We identified the importance of evaluating patients with Enterococcus faecalis bacteraemia for underlying colorectal neoplasia. Routine colonoscopy is recommended in patients with E. faecalis bacteraemia or infective endocarditis with an unclear source of infection.

Characterization of bacteriocinogenic Enterococcus isolates from wild and laboratory rabbits for the selection of autochthonous probiotic strains in Tunisia

AIM

The objective of this study was to characterize lactic acid bacteria (LAB) from rabbits to be used as potential autochthonous probiotic.

METHODS AND RESULTS

Fifteen faecal samples were collected from wild and laboratory rabbits. One hundred and eight isolates were collected and tested for their inhibitory power against eight pathogenic bacteria. Among them, 43 Enterococcus isolates were able to inhibit at least one pathogen. Enterocine genes entA, entB and entP were detected in 14, 17 and 22 isolates, respectively. These isolates were tested for their antibiotic susceptibility and genes encoding virulence factors. Relevant phenotypes of antibiotic resistance were observed especially for ampicillin, vancomycin and linezolid. The following virulence genes were detected (number of positive isolates): hyl (5), esp (8), gelE (30), agg (2), ace (21), efa (6), CylL_L/s (5), cob (26), cpd (32) and ccf (33). Five isolates were considered as safe and showed tolerance to both acid and bile salt.

CONCLUSION

Bacteriocinogenic enterococci isolates from rabbits may show relevant resistance phenotypes and virulence factors. In addition, one Enterococcus durans isolate presents promising autochthonous probiotic candidate.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study reveals interesting properties for E. durans isolate and supports their utilization as autochthonous probiotic in rabbit husbandry.

Risk factors for enterococcal urinary tract infections: a multinational, retrospective cohort study

Complicated urinary tract infection (cUTI) is a frequent cause of morbidity. In this multinational retrospective cohort study, we aimed to demonstrate risk factors for enterococcal UTI. Univariate and multivariate analyses of risk factors for enterococcal infection were performed. Among 791 hospitalized patients with cUTI, enterococci accounted for approximately 10% of cases (78/791). Risk factors for enterococcal UTI in multivariable analysis were male gender, age range of 55-75 years, catheter-associated UTI, and urinary retention. This information may assist treating physicians in their decision-making on prescribing empiric anti-enterococcus treatment to hospitalized patients presenting with cUTI and thus improve clinical outcomes.

COVID-19 related thrombi in ascending and descending thoracic aorta with peripheral embolization: a case report

Background

COVID-19 (severe acute respiratory syndrome coronavirus 2) infected patients have increased risk for thrombotic events, which initially may have been under recognized. The existence of cardiovascular emboli can be directly life threatening when obstructing the blood flow to vital organs such as the brain or other parts of the body. The exact mechanism for this hypercoagulable state in COVID-19 patients yet remains to be elucidated.

Case summary

A 72-year-old man critically ill with COVID-19 was diagnosed with a free-floating and mural thrombus in the thoracic aorta. Subsequent distal embolization to the limbs led to ischaemia and necrosis of the right foot. Treatment with heparin and anticoagulants reduced thrombus load in the ascending and thoracic aorta.

Discussion

One-third of COVID-19 patients show major thrombotic events, mostly pulmonary emboli. The endothelial expression of angiotensin-converting enzyme-2 receptors makes it feasible that in patients with viraemia direct viral-toxicity to the endothelium of also the large arteries results in local thrombus formation. Up to date, prophylactic anticoagulants are recommended in all patients that are hospitalized with COVID-19 infections to prevent venous and arterial thrombotic complications.

Risk Factors for the Acquisition of Enterococcus faecium Infection and Mortality in Patients with Enterococcal Bacteremia: A 5-Year Retrospective Analysis in a Tertiary Care University Hospital

The incidence of bacteremia caused by Enterococcus faecium, which is highly resistant to multiple antibiotics, is increasing in Japan. However, risk factors for the acquisition of E. faecium infection and mortality due to enterococcal bacteremia are not well known. We compared demographic, microbiological, and clinical characteristics using a Cox regression model and univariate analysis. We performed a multivariate analysis to identify risk factors for patients treated between 2014 and 2018. Among 186 patients with enterococcal bacteremia, two groups included in the Kaplan–Meier analysis (E. faecalis (n = 88) and E. faecium (n = 94)) showed poor overall survival in the E. faecium group (HR: 1.92; 95% confidence interval: 1.01–3.66; p = 0.048). The median daily antibiotic cost per patient in the E. faecium group was significantly higher than that in the E. faecalis group ($23 ($13–$34) vs. $34 ($22–$58), p < 0.001). E. faecium strains were more frequently identified with previous use of antipseudomonal penicillins (OR = 4.04, p < 0.001) and carbapenems (OR = 3.33, p = 0.003). Bacteremia from an unknown source (OR = 2.79, p = 0.025) and acute kidney injury (OR = 4.51, p = 0.004) were associated with higher risks of 30-day mortality in patients with enterococcal bacteremia. Therefore, clinicians should provide improved medical management, with support from specialized teams such as those assisting antimicrobial stewardship programs.

Prevalence and Predictors of Antimicrobial Resistance Among Enterococcus spp. From Dogs Presented at a Veterinary Teaching Hospital, South Africa

Background: While surveillance of antimicrobial drug resistance is ongoing in human medicine in South Africa, there is no such activity being performed in veterinary medicine. As a result, there is a need to investigate antimicrobial resistance among enterococci isolated from dogs in South Africa to improve understanding of the status of antimicrobial drug resistance given its public and veterinary public health importance. This study investigated antimicrobial resistance and factors associated with resistance profiles of enterococci isolated from dogs presented for veterinary care at a veterinary teaching hospital in South Africa. Methods: In total 102 Enterococcus isolated between 2007 and 2011 by a bacteriology laboratory at a teaching hospital were included in this study. Antimicrobial susceptibility of the isolates was determined against a panel of 18 antimicrobials using the Kirby Bauer disc diffusion technique. Univariate analysis was used to assess simple associations between year, season, breed group, age group, sex, and specimen as covariates and extensive drug resistance (XDR) as the outcome. Variables that were significant in the univariate analysis at a generous p-value ≤ 0.2 were included in the multivariable logistic models to investigate predictors of XDR. Results: All the Enterococcus isolates were resistant to at least one antimicrobial. High proportions of isolates were resistant against lincomycin (93%), kanamycin (87%), orbifloxacin (85%), and aminogycoside-lincosamide (77%). Ninety three percent (93%), 35.3, and 8.8% of the isolates exhibited multi-drug, extensive-drug and pan-drug resistance, respectively. Only year was significantly (p = 0.019) associated with extensive-drug resistance. Conclusion: Given the zoonotic potential of Enterococcus spp., the high antimicrobial resistance and multi-drug resistance observed in this study are a public health concern from one health perspective. The identified resistance to various antimicrobials may be useful in guiding clinicians especially in resource scarce settings where it is not always possible to perform AST when making treatment decisions.

Linezolid to treat urinary tract infections caused by vancomycin-resistant Enterococcus

Background:

Vancomycin-resistant Enterococcus can cause urinary tract infection. Linezolid possesses antimicrobial activity against vancomycin-resistant Enterococcus but has limited urinary excretion. Minimal data demonstrate efficacy of linezolid for treatment of urinary tract infections.

Objective:

The main aim of this study is to compare post-treatment outcomes of linezolid to other antibiotics with vancomycin-resistant Enterococcus activity in the treatment of urinary tract infection caused by vancomycin-resistant Enterococcus.

Methods:

A retrospective cohort of inpatients within Veterans Health Administration facilities with urinary tract infection caused by vancomycin-resistant Enterococcus was created. Patients with vancomycin-resistant Enterococcus isolated from urine cultures and chart documentation meeting criteria for urinary tract infection were identified. Demographics, comorbidity, treatments, and post-treatment outcomes were extracted from the electronic health record. Outcomes were compared between patients treated with linezolid and alternative antibiotics possessing vancomycin-resistant Enterococcus activity 14 days after treatment completion. Logistic regression adjusted for covariates associated with each outcome.

Results:

Of 4,683 patients with a positive vancomycin-resistant Enterococcus culture, 624 (13%) met criteria for chart review, and 92 (15%) had documentation of urinary tract infection symptoms and treatment. The primary reason for exclusion was asymptomatic bacteriuria (64%). Patients had high Charlson Comorbidity Scores (mean = 8.7; standard deviation (SD) = 3.3), and 70% were located on general medical/surgical wards on the day of culture collection. Linezolid was prescribed in 54 (59%) cases. No difference between linezolid and comparator antibiotics were observed in re-initiation of antibiotics for vancomycin-resistant Enterococcus urinary tract infection (9% and 5% respectively (p = 0.56), (adjusted odds ratio (OR) = 1.90; 95% confidence interval (CI) = 0.34–10.63)), recurrent positive vancomycin-resistant Enterococcus culture (4% and 11%, respectively (p = 0.23), (adjusted OR = 0.36; 95% CI = 0.05–2.31)), or mortality (7% and 3%, respectively (p = 0.39) (adjusted OR = 2.96; 95% CI = 0.37–41.39)).

Conclusion:

Most patients with vancomycin-resistant Enterococcus identified on urine culture were asymptomatic. Linezolid appears effective as comparator antibiotics for the treatment of mild vancomycin-resistant Enterococcus urinary tract infection.

An Update to Enterococcal Bacteremia: Epidemiology, Resistance, and Outcome

BACKGROUND

An increase in resistant gram-positive cocci, especially enterococci, requires an epidemiologic re-assay and its results may affect empirical treatments for these infections.

OBJECTIVE

In this study, we investigated the microbial epidemiology and resistance pattern of enterococcal bacteremia.

METHODS

This study was a cross-sectional study that investigates all cases of positive blood cultures with Enterococcus spp. at a tertiary referral colligates hospital in Tehran in 2018.

RESULTS

Enterococcus spp. was isolated from blood cultures of a total of 73 patients. The most patients were male 42 (57.7%). The mean age of the patients was 58.8 (±18.8) years. Hospital-acquired infection was the most type of infection involving enterococcal bacteremia (80.8%) comparing with community-acquired (6.7%) and health care-associated (12.3%). Renal failure and cancer were the most underlying disease in E. faecalis and E. faecium, respectively. Mortality for Vanco-mycin-resistant enterococci (VRE) was approximately two times more than the sensitive ones. Between the dead/alive groups, the following items were different significantly (P.Value<0.05): Vancomycin resistance for enterococcus isolated, immunodeficiency as underlying disease, Mechanical ventilation, hospitalization period, and the empiric regimen.

CONCLUSION

Increased antibiotic-resistant strains, especially Vancomycin-resistant enterococci (VRE), pose a serious threat to the general public, especially hospitalized patients, and increase mortality. Surveillance of microorganisms and antimi-crobial resistance is a crucial part of an efficient health care system.

Risk factors for enterococcal bacteriuria in dogs: A retrospective study

BACKGROUND

In humans, Enterococcus spp. urinary tract infections (UTI) are commonly associated with urinary catheter-induced urothelial inflammation but this is not the case in dogs.

HYPOTHESIS/OBJECTIVES

To identify risk factors predisposing dogs to enterococcal bacteriuria.

ANIMALS

Seventy dogs with Enterococcus spp. bacteriuria (case) and 70 dogs with Enterococcus coli bacteriuria (control).

METHODS

A single center retrospective case-control study with subjects and controls identified by a medical records search for Enterococcus spp. (subject) or E coli (control) bacteriuria from January 1, 2014 to December 31, 2017. Cases and controls were balanced with respect to average age and weight. Binary logistic regression was used to estimate and test whether the odds of having Enterococcus spp. bacteriuria (instead of E coli) were associated with the presence of any given characteristic.

RESULTS

A history of recurrent bacteriuria was significantly more common in Enterococcus spp. cases than in E coli controls (odds ratio [OR]: 2.07; 95% confidence interval [CI]: 1.04-4.16, P = .04). Comorbidities associated with the presence of Enterococcus spp. bacteriuria included lower urinary tract (LUT) anatomic abnormalities (OR: 2.94; 95% CI: 1.17-8.10, P = .02), urolithiasis (P = .01), and the presence of LUT neoplasia (P = .04). Small frequencies (n = 12 and n = 6, respectively) compromise our ability to precisely estimate the genuine OR for the latter 2 characteristics.

CONCLUSIONS AND CLINICAL IMPORTANCE

If the identified risk factors promote Enterococcus spp. colonization in dogs via induced LUT inflammation similar to people then Enterococcus spp. bacteriuria could be a sentinel for underlying LUT inflammation.

FDG-PET/CT Incidental Detection of Cancer in Patients Investigated for Infective Endocarditis

Background: Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is an imaging technique largely used in the management of infective endocarditis and in the detection and staging of cancer. We evaluate our experience of incidental cancer detection by PET/CT during IE investigations and follow-up.

Methods and Findings: Between 2009 and 2018, our center, which includes an “endocarditis team,” managed 750 patients with IE in a prospective cohort. PET/CT became available in 2011 and was performed in 451 patients. Incidental diagnosis of cancer by PET/CT was observed in 36 patients and confirmed in 34 of them (7.5%) (colorectal n = 17; lung n = 7; lymphoma n = 2; melanoma n = 2; ovarian n = 2; prostate n = 1; bladder n = 1; ear, nose, and throat n = 1; brain n = 1). A significant association has been found between colorectal cancer and Streptococcus gallolyticus and/or Enterococcus faecalis [12/26 vs. 6/33 for other cancers, p = 0.025, odds ratio = 3.86 (1.19–12.47)]. Two patients had a negative PET/CT (a colon cancer and a bladder cancer), and two patients, with positive PET/CT, had a benign colorectal tumor. PET/CT had a sensitivity of 94–100% for the diagnosis of cancer in this patient.

Conclusions: Whole-body PET/CT confirmed the high incidence of cancer in patients with IE and could now be proposed in these cases.

Synergy of the Bacteriocin AS-48 and Antibiotics against Uropathogenic Enterococci

The genus Enterococcus comprises a ubiquitous group of Gram-positive bacteria that can cause diverse health care-associated infections. Their genome plasticity enables easy acquisition of virulence factors as well as antibiotic resistances. Urinary tract infections (UTIs) and catheter-associated UTIs are common diseases caused by enterococci. In this study, Enterococcus strains isolated from UTIs were characterized, showing that the majority were E. faecalis and contained several virulence factors associated to a better colonization of the urinary tract. Their susceptibility against the bacteriocin AS-48 and several antibiotics was tested. AS-48 is a potent circular bacteriocin that causes bacterial death by pore formation in the cell membrane. The interest of this bacteriocin is based on the potent inhibitory activity, the high stability against environmental conditions, and the low toxicity. AS-48 was active at concentrations below 10 mg/L even against antibiotic-resistant strains, whereas these strains showed resistance to, at least, seven of the 20 antibiotics tested. Moreover, the effect of AS-48 combined with antibiotics commonly used to treat UTIs was largely synergistic (with up to 100-fold MIC reduction) and only occasionally additive. These data suggest AS-48 as a potential novel drug to deal with or prevent enterococcal infections.

Prospective multi-center evaluation on risk factors, clinical characteristics and outcomes due to carbapenem resistance in Acinetobacter baumannii complex bacteraemia: experience from the Chinese Antimicrobial Resistance Surveillance of Nosocomial Infections (CARES) Network

Introduction. Increasing evidence demonstrates unfavourable outcomes in bloodstream infections (BSI) due to the carbapenem-resistant Acinetobacter baumannii complex (CRAB).Aim. To investigate the differences in risk factors, clinical characteristics and outcomes in patients with A. baumannii complex BSI stratified by carbapenem resistance, a prospective multi-center study was conducted.Methodology. Information was collected in a predefined form. A total of 317 cases was included for comparison between CRAB BSI vs. carbapenem-susceptible A. baumannii complex (CSAB) BSI. Among these cases, 229 cases were defined as CRAB BSI and 88 cases as CSAB BSI.Results. Univariable analysis showed that male gender, underlying neurologic disease, prior carbapenems exposure, intensive care unit (ICU) stay, presence of central venous catheter, endotracheal intubation, tracheotomy, Foley catheter, nasogastric intubation, lower respiratory tract infections and catheter-related infections were more prevalent in CRAB BSI. Only male gender, prior carbapenems exposure and presence of endotracheal intubation persisted as independent risk factors for acquiring CRAB BSI. Patients with CRAB BSI displayed unfavourable outcomes characterized by failure of pathogen clearance, continuous fever, disease aggravation and higher incidence of 30-day all-cause mortality. Multivariate analysis demonstrated carbapenem resistance as an independent risk factor for 30-day all-cause mortality.Conclusion. Our findings reveal the epidemiological differences between CRAB BSI and CSAB BSI in a Chinese cohort. Our data suggest that carbapenem resistance has a significant impact on mortality for patients with A. baumannii complex BSI, further strengthening the importance of active prevention and control strategies for the spread of CRAB in Chinese hospitals.

Emerging resistance of van genotype in enterococci: A potential menace for therapeutic failure

Objectives:

Emerging cases of vancomycin-resistant enterococci (VRE) are detrimental for the patients. The current study aimed to ascertain the occurrence of VRE, their antibiogram and the van genotype responsible for vancomycin resistance.

Methods:

A total number of 2,958 clinical specimens were processed at Microbiology Department of the Alrazi Health Care, Lahore during the one year (2016-2017) using microbiological culture media, biochemical and serology. Antibiogram of enterococcal strains was performed using disc diffusion and E-test. ATCC Enterococcus faecalis 29212 was used as a quality control strain. The detection of van genotypes was accomplished by multiplex PCR assay.

Results:

Out of the 147 enterococci, 139 (94.6%) were E. faecalis, and 8 (5.4%) were E. faecium. Statistically significant associations of urine (p < 0.001), pus (p < 0.001) and wound swabs (p = 0.001) were observed with E. faecalis. A significant correlation of enterococcal infections (p = 0.05) was seen with female patients. Four (2.9%) strains of E. faecalis found to be VRE with vanB (75%) and vanA (25%) genotypes.

Conclusion:

The emerging strains of VRE (vanB and vanA genotype) in the current study are a potential menace for therapeutic failure, which left the physicians with only linezolid as a therapeutic option.

Emergence of High-level Gentamicin Resistance among Enterococci Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Enterococcus faecalis and Enterococcus faecium are among the main agents associated with nosocomial infections with high mortality in immunocompromised patients. Antibiotic resistance, especially against gentamicin and vancomycin among Enterococci, is a risk factor that could increase the morbidity and mortality rate. 179 Enterococci isolates from burn patients were included in this study. Antibiotic susceptibility testing was done using the disk diffusion test and minimum inhibitory concentration (MIC) was evaluated by agar microdilution. Vancomycin and gentamicin resistance associated genes including vanA, vanB, vanC, aac (6’)-Ie aph(2’’), aph(3’)-IIIa and ant(4’)-Ia were detected by PCR and their statistical relation with antibiotic resistance was evaluated. E. faecalis was the more prevalent strain among our local isolates and showed a higher antibiotic resistance in comparison to E. faecium. Vancomycin had a good antibacterial effect on the Enterococcus spp. isolates; however, resistance to this antibiotic and a high-level gentamicin resistance (HLGR) phenotype were observed. Among van operon genes, vanA was the most prevalent gene and among the gentamicin resistance genes, aph (3’)-IIIa was more frequent. The HLGR Enterococci are a real challenge in nosocomial infections. Vancomycin is a key antibiotic to treat such infections but emergence of VRE in our region could be a real concern and, therefore, phenotypic and molecular surveillance must be considered.

Microbiota and gastrointestinal cancer

Gut microbiota plays important roles in many diseases, including cancer. It may promote carcinogenesis by inducing oxidative stress, genotoxicity, host immune response disturbance, and chronic inflammation. Colorectal cancer, hepatocellular carcinoma, and gastric cancer are the major gastrointestinal tract cancers in Taiwan. The microbiota detected in patients with tubular adenoma and villous/tubulovillous polyps is different from that in healthy controls and patients with hyperplastic polyps. Normalization of the microbiota is observed in patients after colorectal cancer treatment. Furthermore, the liver is exposed to microbiota-associated molecular patterns (MAMPs), bacterial metabolites, and toxins, as it is anatomically connected to the gut via the portal vein. Patients with cirrhosis have significantly higher plasma endotoxin levels than healthy controls. Helicobacter pylori is a well-established risk factor for gastric cancer. Some nitrosating bacteria convert nitrogen compounds in gastric fluid to potentially carcinogenic N-nitroso compounds, which also contribute to gastric cancer development. Growing evidence demonstrates that gut microbiota promotes carcinogenesis. In this review, we discuss the mechanisms and types of microbiota changes involved in these gastrointestinal cancers and the future treatment choices.

Comparative genome analysis reveals key genetic factors associated with probiotic property in Enterococcus faecium strains

BACKGROUND

Enterococcus faecium though commensal in the human gut, few strains provide a beneficial effect to humans as probiotics while few are responsible for the nosocomial infection. Comparative genomics of E. faecium can decipher the genomic differences responsible for probiotic, pathogenic and non-pathogenic properties. In this study, we compared E. faecium strain 17OM39 with a marketed probiotic, non-pathogenic non-probiotic (NPNP) and pathogenic strains.

RESULTS

E. faecium 17OM39 was found to be closely related with marketed probiotic strain T110 based on core genome analysis. Strain 17OM39 was devoid of known vancomycin, tetracycline resistance and functional virulence genes. Moreover, E. faecium 17OM39 genome was found to be more stable due to the absence of frequently found transposable elements. Genes imparting beneficial functional properties were observed to be present in marketed probiotic T110 and 17OM39 strains. Genes associated with colonization and survival within gastrointestinal tract was also detected across all the strains.

CONCLUSIONS

Beyond shared genetic features; this study particularly identified genes that are responsible for imparting probiotic, non-pathogenic and pathogenic features to the strains of E. faecium. Higher genomic stability, absence of known virulence factors and antibiotic resistance genes and close genomic relatedness with marketed probiotics makes E. faecium 17OM39 a potential probiotic candidate. The work presented here demonstrates that comparative genome analyses can be applied to large numbers of genomes, to find potential probiotic candidates.

Enterococcus Faecalis Infective Endocarditis and Colorectal Carcinoma: Case of New Association Gaining Ground

Mostly Streptococcus bovis (S. bovis) bacteremia and endocarditis (60%) has been found to be associated with underlying colorectal cancer (CRC). Enterococcus faecalis (E. faecalis) bacteremia and endocarditis has no identifiable source in most of the cases. E. faecalis is part of normal gut flora that can translocate through the intestine and cause the systemic infection. With any intestinal lesion or tumor, the barrier is breached and the gut flora like E. faecalis can translocate and cause infection. A 55-years-old male known to have non-ischemic cardiomyopathy with implantation of automated implantable cardioverter defibrillator (AICD) and atrial fibrillation presented with weight loss, fever and back pain. He was diagnosed to have E. faecalis bacteremia and subsequent endocarditis and osteomyelitis of T7 - T8 and L4 - L5 vertebrae. He underwent colonoscopy for screening of malignancy because of his age and presenting symptoms suggestive of one. The colonoscopy found pedunculated polyp in sigmoid colon, and after biopsy the histology revealed an invasive well differentiated mucinous adenocarcinoma, with focal squamous differentiation. He underwent removal of AICD and antibiotic treatment for infective endocarditis and osteomyelitis. He underwent sigmoid colectomy with pathology of removed specimen showing adenocarcinoma with negative margins and lymph nodes. In many of the patients with E. faecalis endocarditis, if identifiable the source is genitourinary tract. But in most of the cases the source of E. faecalis bacteremia is unidentified. There is some evidence to suggest that in patients with unidentified source, colonoscopy may reveal a hidden early stage CRC or adenoma. We conclude that in cases of E. faecalis bacteremia and endocarditis with unidentified source, colonoscopy should be considered if feasible to rule out the diagnosis of CRC.

Computational Systems Biology of Metabolism in Infection

A systems approach to elucidate the effect of infection on cell metabolism provides several opportunities from a better understanding of molecular mechanisms to the identification of potential biomarkers and drug targets. This is obvious from the fact that we have witnessed the accelerated use of computational systems biology in the last five years to study metabolic changes in pathogen and/or host cells in response to infection. In this chapter, we aim to present a comprehensive review of the recent research by focusing on genome-scale metabolic network models of pathogen-host systems and genome-wide metabolomics and fluxomics analysis of infected cells.

On the Role of Enterococci in the Bloodstream: Results of a Single-Center, Retrospective, Observational Study at a German University Hospital

This study assesses the clinical relevance of vancomycin-susceptible enterococci in bacteremic patients and compares it with bacteremia due to Staphylococcus aureus and Escherichia coli. During a 5-year-study interval, clinical and diagnostic features of patients with enterococcal bacteremia were compared to those of patients with E. coli or S. aureus bacteremia. Each patient was only counted once per hospital stay. During the 5-year study interval, data from 267 patients with enterococcal bacteremia and from 661 patients with bacteremia due to E. coli or S. aureus were evaluated. In spite of a comparable risk of death, patients with enterococci more frequently needed catecholamines and invasive ventilation. Furthermore, enterococci were more frequently associated with a mixed bacterial flora in bloodstream infections. While fatal sepsis due to E. coli and S. aureus was associated with typical shock symptoms, this association was not confirmed for enterococci. Although enterococcal bacteremia is associated with a risk of dying comparable to that with bacteremia due to E. coli and S. aureus, a lower pathogenic potential of enterococci in bloodstream has to be acknowledged. Enterococci in the bloodstream are more likely to be an epiphenomenon of impending death than its major cause.

A 10-year profile of enterococcal bloodstream infections at a tertiary-care hospital in Japan

OBJECTIVES

The first aim of this study is to characterize the epidemiology of enterococcal bloodstream infections (BSIs) at a Japanese tertiary-care hospital. The second aim is to identify predictive factors for 30-day mortality.

METHODS

We conducted a single center retrospective observational study. All patients with enterococcal BSI between 2005 and 2014 were enrolled. Univariate and multivariate analysis were performed to evaluate predictive factors for 30-day mortality.

RESULTS

A total of 410 patients with enterococcal BSI were enrolled. Enterococcus faecalis was identified in 200 patients (48.8%) and Enterococcus faecium in 124 patients (30.2%). Isolates were susceptible to ampicillin and vancomycin (67.3% and 97.8%, respectively). Isolates that were not susceptible to vancomycin were either Enterococcus casseliflavus or Enterococcus gallinarum. All strains of E. faecalis and 10.8% of E. faecium strains were susceptible to ampicillin. Thirty-day mortality was 24.8%. Predictive factors for 30-day mortality were Charlson Comorbidity Index (CCI) 1-2 (adjusted odds ratio [OR] 6.07, 95% confidence interval [CI]: 1.22-30.2), CCI 3-4 (adjusted OR 8.79, 95% CI: 1.70-45.4), CCI ≥5 (adjusted OR 17.6, 95% CI: 3.52-88.2), E. faecium bacteremia (adjusted OR 2.19, 95% CI: 1.27-3.76), Pitt Bacteremia Score (PBS) ≥5 (adjusted OR 15.1, 95% CI: 6.41-35.6), and source control (adjusted OR 0.39, 95% CI: 0.22-0.72).

CONCLUSION

Vancomycin-resistant strains of E. faecalis and E. faecium were not seen in this cohort. In addition, all strains of E. faecalis and 10.8% of E. faecium strains were susceptible to ampicillin. Predictive factors for 30-day mortality were CCI score, E. faecium bacteremia, PBS score, and source control.

Safety assessment of commensal enterococci from dogs

Enterococci form a complex, diverse, and very important group of bacteria from the technological and food safety aspect, or from the health-improving aspect as probiotics. Generally, enterococci are considered to be of low pathogenic potential, which is associated mostly with clinical strains. In these strains, production of virulence factors as well as resistance to many antimicrobial drugs could complicate treatment of nosocomial infections. Because there is a lack of information on incidence of these attributes in animal commensal enterococci, we screened 160 strains originating from feces of clinically healthy dogs in Eastern Slovakia (n = 105). The predominant species were Enterococcus faecium (57.5%) followed by Enterococcus faecalis (21.9%), and Enterococcus hirae (17.5%), while Enterococcus casseliflavus (1.9%) and Enterococcus mundtii (1.2%) rarely occurred. Among the tested antibiotics, gentamicin (high level) was the most effective drug against canine enterococci (95% of isolates were sensitive). In contrast, the highest resistance recorded (71.9%) was to teicoplanin. PCR screening showed the highest incidence of virulence genes in E. faecalis species. The most frequently detected were genes encoding adhesins efa _Afm and efa _Afs and sex pheromone cpd. IS16 gene, a marker specific for hospital strains, appeared in nine E. faecium strains. No strain was positive for DNase activity, 8.8% of the isolated strains showed gelatinase activity, and almost 100% strains produced tyramine. It seems commensal-derived enterococci from dogs could also to some extent be potential reservoir of risk factors for other microbiota or organisms.

Colon cancer and enterococcus bacteremia co-affection: A dangerous alliance

Adenocarcinoma of the colorectal region is one of the leading causes of cancer-related mortality in the USA and hence an important public health concern. Enterococci are emerging as an important cause of infection in the elderly. While translocation of enteric bacteria into the bloodstream is a known phenomenon in patients with infectious, inflammatory or infiltrative conditions of the bowel, a causative link between Enterococcus bacteremia and colorectal cancer has not been established in medical literature. We report the case of a patient presenting with E. faecalis bacteremia who was also diagnosed with infiltrating adenocarcinoma of the rectum. We discuss a possible relationship between these two conditions.

Antimicrobial resistance and virulence profile of enterococci isolated from poultry and cattle sources in Nigeria

This study investigated the occurrence, antimicrobial resistance and virulence of Enterococcus from poultry and cattle farms. Three hundred and ninety samples: cloacal/rectal swabs (n = 260) and manure (n = 130] were processed for recovery of Enterococcus species. Standard bacteriological methods were used to isolate, identify and characterize Enterococcus species for antimicrobial susceptibility and expression of virulence traits. Detection of antibiotic resistance and virulence genes was carried out by polymerase chain reaction. Enterococcus was recovered from 167 (42.8%) of the 390 samples tested with a predominance of Enterococcus faecium (27.7%). Other species detected were Enterococcus gallinarum, Enterococcus faecalis, Enterococcus hirae, Enterococcus raffinosus, Enterococcus avium, Enterococcus casseliflavus, Enterococcus mundtii and Enterococcus durans. All the isolates tested were susceptible to vancomycin, but resistance to tetracycline, erythromycin, ampicillin and gentamicin was also observed among 61.0, 61.0, 45.1 and 32.7% of the isolates, respectively. Sixty (53.1%) of the isolates were multidrug resistant presenting as 24 different resistance patterns with resistance to gentamicin-erythromycin-streptomycin-tetracycline (CN-ERY-STR-TET) being the most common (n = 11) pattern. In addition to expression of virulence traits (haemolysin, gelatinase, biofilm production), antibiotic resistance (tetK, tetL, tetM, tetO and ermB) and virulence (asa1, gelE, cylA) genes were detected among the isolates. Also, in vitro transfer of resistance determinants was observed among 75% of the isolates tested. Our data revealed poultry, cattle and manure in this area are hosts to varying Enterococcus species harbouring virulence and resistance determinants that can be transferred to other organisms and also are important for causing nosocomial infection.

Evaluation of polymorphisms in pbp4 gene and genetic diversity in penicillin-resistant, ampicillin-susceptible Enterococcus faecalis from hospitals in different states in Brazil

The aim of the present study was to verify whether penicillin-resistant, ampicillin-susceptible Enterococcus faecalis (PRASEF) occurred in Brazil prior to the beginning of the 21st century, and to verify whether ampicillin susceptibility can predict susceptibility to other β-lactams in E. faecalis with this inconsistent phenotype. The presence of polymorphisms in the pbp4 gene and genetic diversity among the isolates were investigated. Of 21 PRASEF analyzed, 5 (23.8%) and 4 (19.0%) were imipenem and piperacillin resistant simultaneously by disk diffusion and broth dilution respectively, contradicting the current internationally accepted standards of susceptibility testing. Sequencing of pbp4 gene revealed an amino acid substitution (Asp-573→Glu) in all PRASEF isolates but not in the penicillin-susceptible, ampicillin-susceptible E. faecalis. Most PRASEF (90.5%) had related pulsed-field gel electrophoresis profiles, but were different from other PRASEF described to date. Results demonstrate that penicillin-resistant, ampicillin-susceptible phenotype was already a reality in the 1990s in E. faecalis isolates in different Brazilian states, and some of these isolates were also imipenem- and piperacillin-resistant; therefore, internationally accepted susceptibility criteria cannot be applied to these isolates. According to pbp4 gene sequencing, this study suggests that a specific amino acid substitution in pbp4 gene found in all PRASEF analyzed is associated with penicillin resistance.