Risk Factors and Outcomes of Endocarditis Due to Non-HACEK Gram-Negative Bacilli: Data from the Prospective Multicenter Italian Endocarditis Study Cohort. Antimicrob Agents Chemother. 2018;62:e02208-17. [PMID: 29378721 DOI: 10.1128/aac.02208-17]

Clinical characteristics and outcomes in pseudomonas endocarditis: a systematic review of individual cases : Systematic review of pseudomonas endocarditis

BACKGROUND

The landscape of Pseudomonas infective endocarditis (IE) is evolving with the widespread use of cardiac implantable devices and hospital-acquired infections. This systematic review aimed to evaluate the emerging risk factors and outcomes in Pseudomonas IE.

METHODS

A literature search was performed in major electronic databases (PubMed, Scopus, and Google Scholar) with appropriate keywords and combinations till November 2023. We recorded data for risk factors, diagnostic and treatment modalities. This study is registered with PROSPERO, CRD42023442807.

RESULTS

A total of 218 cases (131 articles) were included. Intravenous drug use (IDUs) and prosthetic valve endocarditis (PVE) were major risk factors for IE (37.6% and 22%). However, the prosthetic valve was the predominant risk factor in the last two decades (23.5%). Paravalvular complications (paravalvular leak, abscess, or pseudoaneurysm) were described in 40 cases (18%), and the vast majority belonged to the aortic valve (70%). The mean time from symptom onset to presentation was 14 days. The incidence of difficult-to-treat resistant (DTR) pseudomonas was 7.4%. Valve replacement was performed in 57.3% of cases. Combination antibiotics were used in most cases (77%), with the aminoglycosides-based combination being the most frequently used (66%). The overall mortality rate was 26.1%. The recurrence rate was 11.2%. Almost half of these patients were IDUs (47%), and most had aortic valve endocarditis (76%).

CONCLUSIONS

This review highlights the changing epidemiology of Pseudomonas endocarditis with the emergence of prosthetic valve infections. Acute presentation and associated high mortality are characteristic of Pseudomonas IE and require aggressive diagnostic and therapeutic approach.

Infective endocarditis due to Citrobacter koseri following testicular trauma: case report and literature review

Infective endocarditis (IE) is a condition with low prevalence but high mortality rates within intensive care units. Microbiologically, most cases are attributed to Gram-positive cocci, while Gram-negative bacilli are less commonly involved. This case report describes a patient with IE caused by Citrobacter koseri (C. koseri) with secondary bacteremia due to blunt testicular trauma and epididymitis. We conducted a review of the literature to assess the clinical and associated risk factors of this underreported condition. Elderly and urinary tract infections could be associated with this entity. Cefazolin was used as the final targeted treatment. The use of precision medicine in IE is required for specific interventions.

What is the clinical significance of 'heteroresistance' in nonfermenting Gram-negative strains?

PURPOSE OF REVIEW

The aim of this study was to discuss the potential clinical significance of heteroresistance in nonfermenting Gram-negative bacilli (GNB).

RECENT FINDINGS

Recently, heteroresistance has been considered potentially responsible for clinical failure in Acinetobacter baumannii infections. This raised a scientific debate, still open, about the potential clinical significance of heteroresistance in nonfermenting GNB.

SUMMARY

We reviewed the literature of last 20 years and found a limited number of studies evaluating the relationship between heteroresistance and clinical outcome in nonfermenting GNB. Unlike Gram-positive bacteria, heteroresistance is reported in a significant proportion of nonfermenting GNB with some studies describing it in all tested strains and for several antibiotics (including tigecycline, carbapenems, levofloxacin, cefiderocol, colistin). One important issue is the need for validated detection method since the population analysis profile test, that is considered the gold standard, requires high costs and time. Studies evaluating the correlation between heteroresistance and clinical outcome are contrasting and have several limitations. Although in-vitro detection of heteroresistance in nonfermenting GNB has not been associated with in-vivo treatment failure, its presence may suggest to prefer combination regimens instead monotherapy when treating infections by nonfermenters. Further studies are needed to clarify the clinical significance of heteroresistance.

A rare Serratia marcescens-associated acute endocarditis of a tricuspid valve in an intravenous drug user : A case report and literature review

Serratia marcescens is a gram-negative bacillus that is an opportunistic agent in respiratory tract infections, urinary tract infections, and septicemia. It is rarely also a cause of infective endocarditis which follows a rapid and devastating course, typically in persons with history of intravenous drug use (IDU). This article reports a fatal case of a 27-year-old patient with a known history of IDU, who presented with clinical symptoms concerning right-sided endocarditis as well as signs of acute respiratory distress syndrome. Finally, a detailed review of the literature is provided concerning the acute endocarditis of a tricuspid valve, especially associated with Serratia marcescens infection.

Non-HACEK gram-negative bacilli endocarditis: a multicentre retrospective case-control study

BACKGROUND

Infective endocarditis (IE) caused by non-HACEK gram-negative bacilli (GNB) is poorly characterised and may be emerging as a consequence of medical progress.

METHODS

We performed an observational retrospective case-control study. Cases were non-HACEK GNB IE, definite or possible (modified Duke criteria), diagnosed in adults between 2007 and 2020 in six French referral hospitals. Two controls were included for each case (IE due to other bacteria, matched by sites and diagnosis date).

RESULTS

Non-HACEK GNB were identified in 2.4% (77/3230) of all IE during the study period, with a mean age of 69.2 ± 14.6 years, and a large male predominance (53/77, 69%). Primary pathogens were Escherichia coli (n = 33), Klebsiella sp. (n = 12) and Serratia marcescens (n = 9), including eight (10%) multidrug-resistant GNB. Compared to controls (n = 154: 43% Streptococcus sp., 41% Staphylococcus sp. and 12% Enterococcus sp.), non-HACEK GNB IE were independently associated with intravenous drug use (IVDU, 8% vs. 2%, p = .003), active neoplasia (15% vs. 6%, p = .009), haemodialysis (9% vs. 3%, p = .007) and healthcare-associated IE (36% vs. 18%, p = .002). Urinary tract was the main source of infection (n = 25, 33%) and recent invasive procedures were reported in 29% of cases. Non-HACEK GNB IE were at lower risk of embolism (31% vs. 47%, p = .002). One-year mortality was high (n = 28, 36%). Comorbidities, particularly malignant hemopathy and cirrhosis, were associated with increased risk of death.

CONCLUSIONS

Non-HACEK GNB are rarely responsible for IE, mostly as healthcare-associated IE in patients with complex comorbidities (end-stage renal disease, neoplasia), or in IVDUs.

Survey of Bacterial Isolates and Their Antimicrobial Susceptibility Patterns from Dogs with Infective Endocarditis

Infective endocarditis (IE) is a potentially fatal disease in dogs. Limited information exists regarding the characterization of bacterial isolates from dogs with IE. The objective of this study was to describe bacterial isolates associated with IE and their antimicrobial susceptibility patterns. A retrospective analysis of dogs with IE and bacterial isolates was performed, and antimicrobial susceptibility was interpreted using current veterinary cut points where available. The susceptibility rate was assessed for association with survival and previous antimicrobial administration. Fifty-one bacterial isolates were identified from 45 dogs, and 33 had antimicrobial susceptibility performed. Staphylococcus spp. (14/51; 27.5%) was the most common organism. Antimicrobials with the lowest susceptibility rate were ampicillin (19/26; 73%), doxycycline (16/22; 73%), and enrofloxacin (22/29; 76%) with 12/33 (36%) of isolates exhibiting multidrug resistance (MDR). Individual antimicrobial resistances and the MDR rate were not associated with a difference in survival rate. Bacterial isolates from dogs that had received fluoroquinolone antimicrobials in the month before diagnosis had a higher rate of non-intrinsic fluoroquinolones resistance (5/8;62.5%) compared to those that did not receive fluoroquinolones (2/21; 9.5%) (p = 0.03). Antimicrobial resistance and MDR phenotype were common in this study. Culture and antimicrobial susceptibility testing should be pursued in dogs with IE to help guide antimicrobial therapy.

Mortality Attributable to Bloodstream Infections Caused by Different Carbapenem-Resistant Gram-Negative Bacilli: Results From a Nationwide Study in Italy (ALARICO Network)

BACKGROUND

Our aim was to analyze mortality attributable to carbapenem-resistant (CR) gram-negative bacilli (GNB) in patients with bloodstream infections (BSIs).

METHODS

Prospective multicentric study including patients with GNB-BSI from 19 Italian hospitals (June 2018-January 2020). Patients were followed-up to 30 days. Primary outcomes were 30-day mortality and attributable mortality. Attributable mortality was calculated in the following groups: Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales, metallo-β-lactamases (MBL)-producing Enterobacterales, CR-Pseudomonas aeruginosa (CRPA), CR-Acinetobacter baumannii (CRAB). A multivariable analysis with hospital fixed-effect was built to identify factors associated with 30-day mortality. Adjusted OR (aORs) were reported. Attributable mortality was calculated according to the DRIVE-AB Consortium.

RESULTS

Overall, 1276 patients with monomicrobial GNB BSI were included: 723/1276 (56.7%) carbapenem-susceptible (CS)-GNB, 304/1276 (23.8%) KPC-, 77/1276 (6%) MBL-producing CRE, 61/1276 (4.8%) CRPA, and 111/1276 (8.7%) CRAB BSI. Thirty-day mortality in patients with CS-GNB BSI was 13.7% compared to 26.6%, 36.4%, 32.8% and 43.2% in patients with BSI by KPC-CRE, MBL-CRE, CRPA and CRAB, respectively (P < .001). On multivariable analysis, age, ward of hospitalization, SOFA score, and Charlson Index were factors associated with 30-day mortality, while urinary source of infection and early appropriate therapy resulted protective factors. Compared to CS-GNB, MBL-producing CRE (aOR 5.86, 95% CI 2.72-12.76), CRPA (aOR 1.99, 95% CI 1.48-5.95) and CRAB (aOR 2.65, 95% CI 1.52-4.61) were significantly associated with 30-day mortality. Attributable mortality rates were 5% for KPC-, 35% for MBL, 19% for CRPA, and 16% for CRAB.

CONCLUSIONS

In patients with BSIs, carbapenem-resistance is associated with an excess of mortality, with MBL-producing CRE carrying the highest risk of death.

Infective Endocarditis due to Non-HACEK Gram-Negative Bacilli: Clinical Characteristics and Risk Factors from a Prospective Multicenter Brazilian Cohort

Background: Non-HACEK Gram-negative bacilli (NGNB) infective endocarditis (IE) has a growing frequency. We aimed to describe cases of NGNB IE and find associated risk factors. Methods: We conducted a prospective observational study of consecutive patients with definitive IE according to the modified Duke criteria in four institutions in Brazil. Results: Of 1154 adult patients enrolled, 38 (3.29%) had IE due to NGNB. Median age was 57 years, males predominated, accounting for 25/38 (65.8%). Most common etiologies were Pseudomonas aeruginosa and Klebsiella spp. (8 episodes, 21% each). Worsening heart failure occurred in 18/38 (47.4%). Higher prevalence of embolic events was found (55,3%), mostly to the central nervous system 7/38 (18.4%). Vegetations were most commonly on aortic valves 17/38 (44.7%). Recent healthcare exposure was found in 52.6% and a central venous catheter (CVC) in 13/38 (34.2%). Overall mortality was 19/38 (50%). Indwelling CVC (OR 5.93; 95% CI, 1.29 to 27.3; p = 0.017), hemodialysis (OR 16.2; 95% CI, 1.78 to 147; p = 0.008) and chronic kidney disease (OR 4.8; 95% IC, 1.2 to 19.1, p = 0.049) were identified as risk factors for mortality. Conclusions: The rate of IE due to NGNB was similar to that in previous studies. Enterobacterales and P. aeruginosa were the most common etiologies. NGNB IE was associated with central venous catheters, prosthetic valves, intracardiac devices and hemodialysis and had a high mortality rate.

Heartbreaking Decisions: The Dogma and Uncertainties of Antimicrobial Therapy in Infective Endocarditis

Infective endocarditis (IE) is a rare but increasingly prevalent disease with high morbidity and mortality, requiring antimicrobials and at times surgical intervention. Through the decades of healthcare professionals' experience with managing IE, certain dogmas and uncertainties have arisen around its pharmacotherapy. The introduction of new antimicrobials and novel combinations are exciting developments but also further complicate IE treatment choices. In this review, we provide and evaluate the relevant evidence focused around contemporary debates in IE treatment pharmacotherapy, including beta-lactam choice in MSSA IE, combination therapies (aminoglycosides, ceftaroline), the use of oral antimicrobials, the role of rifamycins, and long-acting lipoglycopeptides.

Native Mitral Valve Endocarditis Caused by a Non-HACEK Gram-Negative Pathogen in a Hemodialysis Patient

Infective endocarditis (IE) due to non-HACEK (species other than Hemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) bacteremia accounts for less than 2% of all IE cases but is proven to be associated with higher mortality, even more so in hemodialysis (HD) patients. Few data are available in the literature concerning non-HACEK Gram-negative (GN) IE in this immunocompromised population with multiple comorbidities. We report the atypical clinical presentation of an elderly HD patient diagnosed with a non-HACEK GN IE, namely E. coli, successfully treated with intravenous (IV) antibiotics. The objective of this case study and related literature was to highlight the limited applicability of the modified Duke criteria in the HD population, as well as the frailty of HD patients that increases their susceptibility to IE due to unexpected microorganisms that could have fatal consequences. The need for a multidisciplinary approach of an IE in HD patients is therefore imperative.

Escherichia coli: A Rare Cause of Prosthetic Valve Endocarditis

Prosthetic valve endocarditis (PVE) is a complication of valve replacement associated with high morbidity and mortality. Escherichia coli (E. coli) is rarely associated with infective endocarditis (IE), accounting for less than 1% of the cases reported. The low frequency is attributed to the organism's low affinity to adhere to the endocardial endothelium. Risk factors that may play a role in developing IE by E. coli include age above 70, diabetes mellitus, a genitourinary source of infection, female sex, healthcare contact, implanted endovascular devices, and immunosuppression. We present a 70-year-old Hispanic woman who arrived with constitutional symptoms and persistent urinary complaints. She had diabetes mellitus, recurrent urinary tract infections, and native mitral valve IE treated with antibiotic therapy and tissue valve replacement. The valve was replaced with a mechanical valve a second time due to malfunctioning. The patient was found to have E. coli bacteremia and ultimately diagnosed with PVE. She was treated solely with ceftriaxone and gentamicin combination therapy resulting in complete resolution of valve vegetations. Our case represents the 11th report of this uncommon disease and illustrates its epidemiology and associated risk factors. We summarize the previous 10 cases reported and highlight the lack of prospective trial data to define optimal therapy for managing PVE caused by E. coli.

Skin and soft tissue infections in the elderly

PURPOSE OF REVIEW

To highlight the peculiarity of skin and soft tissue infections (SSTIs) in elderly patients and to provide useful elements for their optimal management.

RECENT FINDINGS

In the COVID-19 era, early discharge from the hospital and implementation of outpatient management is of key importance.

SUMMARY

Elderly patients are at high risk of SSTIs due to several factors, including presence of multiple comorbidities and skin factors predisposing to infections. Clinical presentation may be atypical and some signs of severity, such as fever and increase in C-reactive protein, may be absent or aspecific in this patients population. An appropriate diagnosis of SSTIs in the elderly is crucial to avoid antibiotic overtreatment. Further studies should explore factors associated with bacterial superinfections in patients with pressure ulcers or lower limb erythema. Since several risk factors for methicillin-resistant Staphylococcus aureus (MRSA) may coexist in elderly patients, these subjects should be carefully screened for MRSA risk factors and those with high risk of resistant etiology should receive early antibiotic therapy active against MRSA. Physicians should aim to several objectives, including clinical cure, patient safety, early discharge and return to community. SSTIs in the elderly may be managed using long-acting antibiotics, but clinical follow-up is needed.

Risk factors for Gram-negative bacterial infection of cardiovascular implantable electronic devices: multicentre observational study (CarDINe Study)

BACKGROUND

Infections of cardiovascular implantable electronic devices (CIED) are mainly due to Gram-positive bacteria (GPB). Data about Gram-negative bacteria CIED (GNB-CIED) infections are limited. This study aimed to investigate risk factors, clinical and diagnostic characteristics, and outcome of patients with GNB-CIED.

METHODS

A multicentre, international, retrospective, case-control-control study was performed on patients undergoing CIED implantation from 2015 to 2019 in 17 centres across Europe. For each patient diagnosed with GNB-CIED, one matching control with GPB-CIED infection and two matching controls without infection were selected.

RESULTS

A total of 236 patients were enrolled: 59 with GNB-CIED infection, 59 with GPB-CIED infection and 118 without infection. No between-group differences were found regarding clinical presentation, diagnostic and therapeutic management. A trend toward a higher rate of fluorodeoxyglucose positron emission computed tomography (FDG PET/CT) positivity was observed among patients with GNB than in those with GPB-CIED infection (85.7% vs. 66.7%; P = 0.208). Risk factors for GNB-CIED infection were Charlson Comorbidity Index Score (relative risk reduction, RRR = 1.211; P = 0.011), obesity (RRR = 5.122; P = 0.008), ventricular-pacing ventricular-sensing inhibited-response pacemaker implantation (RRR = 3.027; P = 0.006) and right subclavian vein site of implantation (RRR = 5.014; P = 0.004). At 180-day survival analysis, GNB-CIED infection was associated with increased mortality risk (HR = 1.842; P = 0.067).

CONCLUSIONS

Obesity, high number of comorbidities and right subclavian vein implantation site were associated with increased risk of GNB-CIED infection. A prompt therapeutic intervention that may be guided using FDG PET/CT is suggested in patients with GNB-CIED infection, considering the poorer outcome observed in this group.

Evidence-Based Treatment of Pseudomonas aeruginosa Infections: A Critical Reappraisal

Multidrug-resistant (MDR)/extensively drug-resistant (XDR) Pseudomonas aeruginosa is emerging as a major threat related to adverse patient outcomes. The goal of this review is to describe evidence-based empiric and targeted treatment regimens that can be exploited when dealing with suspected or confirmed infections due to MDR/XDR P. aeruginosa. P. aeruginosa has inherent resistance to many drug classes, the capacity to form biofilms, and most importantly, the ability to quickly acquire resistance to ongoing treatments. Based on the presence of risk factors for MDR/XDR infections and local epidemiology, where large proportions of strains are resistant to classic beta-lactams, the recommended empirical treatment for suspected P. aeruginosa infections is based on ceftolozane-tazobactam or ceftazidime-avibactam. Where local epidemiology indicates low rates of MDR/XDR and there are no risk factors, a third or fourth generation cephalosporin can be used in the context of a "carbapenem-sparing" strategy. Whenever feasible, antibiotic de-escalation is recommended after antimicrobial susceptibility tests suggest that it is appropriate, and de-escalation is based on different resistance mechanisms. Cefiderocol and imipenem-cilastatin-relebactam withstand most resistance mechanisms and may remain active in cases with resistance to other new antibiotics. Confronting the growing threat of MDR/XDR P. aeruginosa, treatment choices should be wise, sparing newer antibiotics when dealing with a suspected/confirmed susceptible P. aeruginosa strain and choosing the right option for MDR/XDR P. aeruginosa based on specific types and resistance mechanisms.

Infective Endocarditis by Pasteurella Species: A Systematic Review

Pasteurella spp. are non-motile, facultative anaerobic, Gram-negative coccobacilli that are commonly found in the oral cavity and the gastrointestinal tract of some animals and are known to be the cause of infections. Usually, infections by Pasteurella spp. in humans is more common in the context of an animal bite leading to a skin and soft tissue infection (SSTI). Infective endocarditis (IE) is rarely caused by Pasteurella spp.; however, it can pose diagnostic and therapeutic dilemmas due to its rarity. The aim of the present study was to systematically review all cases of IE by Pasteurella spp. in the literature. A systematic review was performed of PubMed, Scopus and the Cochrane Library (through 20 December 2021) for studies providing data on epidemiology and clinical and microbiological characteristics as well as data on treatment and outcomes of IE by Pasteurella spp. A total of 28 studies containing data for 28 patients were included. Prosthetic valve was present in 21.4% of patients. The aorta was the most commonly involved intracardiac site. Fever, sepsis, septic shock and heart failure were the most common clinical presentations. Cephalosporins, aminopenicillins and penicillin were the antimicrobials used most commonly. Overall mortality was 17.9%.

Infective Endocarditis in the Elderly: Challenges and Strategies

The specific management of infective endocarditis (IE) in elderly patients is not specifically addressed in recent guidelines despite its increasing incidence and high mortality in this population. The term "elderly" corresponds to different ages in the literature, but it is defined by considerable comorbidity and heterogeneity. Cancer incidence, specifically colorectal cancer, is increased in older patients with IE and impacts its outcome. Diagnosis of IE in elderly patients is challenging due to the atypical presentation of the disease and the lower performance of imaging studies. Enterococcal etiology is more frequent than in younger patients. Antibiotic treatment should prioritize diminishing adverse effects and drug interactions while maintaining the best efficacy, as surgical treatment is less commonly performed in this population due to the high surgical risk. The global assessment of elderly patients with IE, with particular attention to frailty and geriatric profiles, should be performed by multidisciplinary teams to improve disease management in this population.

Serratia Marcescens, a Rare and Devastating Cause of Endocarditis: A Case Report and Review of the Literature

Serratia marcescens is a gram-negative bacillus that is an opportunistic agent in respiratory tract infections, urinary tract infections, and septicemia. It is rarely a cause of infective endocarditis, but in cases of endocarditis, it follows a rapid and devastating course.

A previously healthy female in her mid-50s presented with fever, abdominal pain, right lower extremity pain, and diarrhea. Blood cultures were positive for S. marcescens, and additional evaluation revealed infarction in the spleen and kidneys, raising concern for endocarditis with associated embolic phenomena. The patient was subsequently found to have an embolus in the right popliteal artery and underwent a right popliteal thromboembolectomy. Antimicrobial therapy with cefepime and gentamicin was begun. A transesophageal echocardiogram revealed a large, mobile mitral valve vegetation. Care was complicated by intracranial hemorrhage, and the decision was made to withdraw care.

A review of the databases Embase and PubMed revealed 63 additional cases of S. marcescens endocarditis. Analysis of these cases demonstrated a preponderance of aortic and mitral valve involvement, not tricuspid valve involvement, despite a risk factor of intravenous drug use in over 60% of cases. Mortality was 50%, and sequelae such as congestive heart failure and renal insufficiency occurred in the majority of survivors. In conclusion, S. marcescens is a rare but devastating cause of endocarditis with a primary risk factor of intravenous drug use but with a predilection for left-sided valvular lesions, not right-sided lesions.

Infective endocarditis of a native aortic valve due to Pseudomonas aeruginosa complicated by progressive multi-drug resistance

BACKGROUND

Treatment of infective endocarditis secondary to Pseudomonas aeruginosa can be challenging because of this organism's ability to acquire antimicrobial resistance over time.

METHODS

We describe a patient with native aortic valve infective endocarditis due to P. aeruginosa who developed progressive multi-drug resistance while on therapy. The resistance mechanisms were characterized using whole-genome sequencing.

RESULTS

We identified two mutations in subsequent isolates (dacB and OprD) that conferred resistance to anti-pseudomonal penicillins, cephalosporins, and carbapenems. The patient was treated with combination high-dose continuous infusion meropenem and ciprofloxacin therapy, in addition to bioprosthetic aortic valve replacement and repair of ventricular septal wall defect. Antibiotics were continued for 6 weeks post-cardiac surgery and the patient remains infection free 18 months post-completion of antibiotic therapy.

CONCLUSION

Clinicians should be aware of the ability of P. aeruginosa to acquire resistance mechanisms in response to selective antibiotic pressures in high-inoculum infections such as infective endocarditis. The mutations identified in this case report correlated well with the evolving antimicrobial resistance profile observed.

Infective Endocarditis by Moraxella Species: A Systematic Review

Moraxella catarrhalis is the most clinically relevant species among Moraxella spp. For decades, it was considered to be part of the normal human flora in the upper respiratory tract. However, since the late 1970s, considerable evidence has proposed that M. catarrhalis is an important pathogen in the human respiratory tract. Even though Infective Endocarditis (IE) is rarely caused by Moraxella spp., these infections can be problematic due to the lack of experience in their management. The aim of this study was to systematically review all published cases of IE by Moraxella spp. A systematic review of PubMed, Scopus and Cochrane library (through 8 December 2021) for studies providing epidemiological, clinical, microbiological data as well as treatment data and outcomes of IE by Moraxella spp. was performed. A total of 27 studies, containing data for 31 patients, were included. A prosthetic valve was present in 25.8%. Mitral valve was the most commonly infected site. Fever, sepsis and embolic phenomena were the most common clinical presentations. Cephalosporins, aminoglycosides, aminopenicillins and penicillin were the most commonly used antimicrobials. Overall mortality was 12.9%.

Importance of early diagnosis and surgical treatment of calcified amorphous tumor-related native valve endocarditis caused by Escherichia coli: a case report

BACKGROUND

Unlike Escherichia coli bacteremia, which is common, E. coli endocarditis is uncommon, particularly in patients with native valve, leading to its delayed diagnosis.

CASE PRESENTATION

We present a case of infective endocarditis caused by E. coli in a 78-year-old Japanese man with type 2 diabetes, involving persistent bacteremia and vegetation on the mitral valve (measuring 18 × 4.2 mm in diameter). He presented with recurrent fever after antimicrobial treatment for pyelonephritis. He received antibiotic therapy for 6 weeks and required surgical removal of a calcified amorphous tumor and vegetation with mitral valvuloplasty 7 days after admission. Despite an episode of multiple cerebral infarctions, he recovered fully from the infection.

CONCLUSIONS

Follow-up blood cultures should be performed for Gram-negative bacilli bacteremia among patients with unknown focus and an atypical clinical course after treatment. Early diagnosis and aggressive surgical intervention are paramount to achieving good clinical outcomes.

A Rare Presentation of Infective Endocarditis Due to Serratia marcescens

Serratia marcescens is an opportunistic organism that can commonly cause respiratory tract infections in immunocompromised individuals. It has also been shown to cause urinary tract infections and soft tissue infections. It has several virulence factors including fimbriae-like adhesions that allow for surface attachment and biofilm formation to increase the likelihood of infections in humans. However, it has rarely been shown to cause infective endocarditis but has an increased mortality compared to the usual microbial agents associated with it (Staphylococcus and Streptococcus). Therefore, a high index of suspicion is necessary to accurately diagnose and treat patients at risk. Most published cases of S. marcescens endocarditis show that almost all described patients had chronic medical conditions or cardiovascular abnormalities. Furthermore, treatment has become difficult as S. marcescens has been shown to exhibit antibacterial resistance with beta-lactamase production.

Here, we present a complicated case of S. marcescens pneumonia and infective endocarditis with a good prognosis. Our patient had a rapid onset of complications (i.e. including joint infections, splenic abscesses, myositis, and septic arthritis), despite the initial benign presentation concerning for pneumonia. However, the patient had a favorable outcome due to the prompt work-up and treatment that was initiated. Therefore, S. marcescens bacteremia in a patient with risk factors should prompt further investigation with a thorough evaluation of source followed by immediate management. This case highlights the fastidious nature of S. marcescens. Further investigation needs to be done to elucidate the pathogenesis of the organism that can serve as a target for future therapeutic intervention.

An Interesting Case of Serratia Endocarditis in a Patient With Chronic Myeloid Leukemia

Serratia is a rare cause of infective endocarditis (IE) and usually occurs in patients with underlying risk factors, such as intravenous (IV) drug use, and human immunodeficiency virus patients. Gram-negative bacteria endocarditis is associated with high mortality when it involves the left side of the heart and often requires surgical intervention in addition to medical treatment. Although most gram-negative endocarditis cases are hospital-acquired, community cases have also been reported. Here, we present a case of Serratia endocarditis in an individual who was later diagnosed with chronic myeloid leukemia (CML) during the same hospitalization. The patient was treated with IV meropenem and started on targeted therapy for CML. CML is presumed to have likely predisposed the patient to bacteremia and IE.

Rare case of Proteus mirabilis native mitral valve endocarditis in an immunocompromised patient

BACKGROUND

Bacterial infective endocarditis caused by Proteus mirabilis is rare and there are few cases in the literature. The natural history and treatment of this disease is not as clear but presumed to be associated with complicated urinary tract infection (cUTI).

CASE PRESENTATION

A 65-year-old female with a history of rheumatoid arthritis, factor V Leiden hypercoagulability, and prior saddle pulmonary embolism presented to the emergency department following a mechanical fall. Computed Tomography showed evidence of acute/subacute splenic emboli. Complicated UTI was likely secondary to a ureteral stone. Blood and urine cultures also grew out P. mirabilis. Transthoracic echocardiography revealed a mobile echogenic density on the anterior mitral valve (MV) leaflet consistent with a vegetation. The patient underwent MV replacement, and P. mirabilis was isolated from the surgically removed valve.

CONCLUSIONS

We hypothesize that the patient's immunocompromised status following steroid and Janus Kinase inhibitor usage for rheumatoid arthritis contributed to Gram-negative bacteremia following P. mirabilis UTI, ultimately seeding the native MV. Additional studies with larger numbers of Proteus endocarditis cases are needed to investigate an association between immunosuppression and Proteus species endocarditis.

Gram-negative endocarditis: disease presentation, diagnosis and treatment

PURPOSE OF REVIEW

Gram-negative bacilli (GNB) cause between 1% and 10% of infective endocarditis (IE). Most episodes are caused by microorganisms of the Haemophilus spp., Aggregatibacter spp. Cardiobacterium spp., Eikenella spp., and Kingella spp (HACEK) group. The frequency of IE caused by non-HACEK (GNB-IE) has increased in recent years. Uncertainties persist regarding its best medical treatment and the appropriateness and timing of surgical treatment. In addition, there are new drugs with activity against multiresistant microorganisms, of which there is little experience in this disease. We review this topic by answering the most frequently asked questions that arise among our colleagues.

RECENT FINDINGS

HACEK microorganisms cause 1.5-2% of IE with only a 2% mortality. In contrast, non-HACEK GNB-IE accounts for 2.5-3% of all IE cases and is associated with nosocomial acquisition, advanced age, solid organ transplantation and 20-30% mortality. Drug addiction is important in areas with epidemic opioid abuse.

SUMMARY

The frequency of IE caused by GNB has been modified in recent years. HACEK episodes are no longer treated with ampicillin and aminoglycosides. In non-HACEK GNB-IE, combination therapy with a beta-lactam and a quinolone or aminoglycoside is recommended. The surgical indication and its value are evident in many patients. Management should rely on a collaborative group with experience in this disease.

Escherichia coli prosthetic valve endocarditis from a non-genitourinary source

•

E. coli is an infrequent cause of infective endocarditis due to is limited ability to adhere to heart valves.

•

There is a notable increase in the share of total cases of E. coli infective endocarditis due to prosthetic valve infections.

•

There is an increased recognition of non-genitourinary sources of E. coli prosthetic valve endocarditis.

•

The overall mortality rate is declining for E. coli prosthetic valve endocarditis cases.

Escherichia coli (E. coli) is a rare cause of infective endocarditis due to its lack of traditional virulence factors that promote endocardial adherence. Previous case reports of E. coli infective endocarditis demonstrate specific risk factors to include advanced age over 70, female sex, diabetes, immunosuppression, and intravascular or cardiac devices. Antecedent genitourinary infection is the most common source. We present a case of a 55-year-old Honduran man with a recent bioprosthetic mitral valve replacement and tricuspid valve repair who presented with one month of subjective fevers, night sweats, anorexia, and significant weight loss. After extensive work-up, the patient was diagnosed with E. coli infective endocarditis secondary to E. coli growth in blood cultures and a transesophageal echocardiogram (TEE) revealing a vegetation on his prosthetic mitral valve. An indolent gastrointestinal source was suspected to be the source of infection with imaging only notable for mild periappendiceal stranding concerning for a possible site of antecedent inflammation. He was treated with a 6-week course of ceftriaxone and gentamicin inpatient and then discharged on trimethoprim-sulfamethoxazole suppressive therapy with serial echocardiographic follow-up given the persistent small vegetation on repeat echocardiogram. Our case report and review of ten recent cases of prosthetic valve endocarditis described in the literature illustrates several common features of the epidemiology, presentation, and management of E. coli prosthetic valve endocarditis including more commonly reported non-genitourinary sources of bacteremia, a trend towards more frequent surgical interventions, and a declining mortality rate.

Non-HACEK gram negative bacilli endocarditis: Analysis of a national prospective cohort

BACKGROUND

Infective endocarditis (IE) due to non-HACEK bacilli (Haemophilus species, Actinobacillus, Cardiobacterium, Eikenella, or Kingella) is uncommon and poorly described. The objectives of this study were to describe non-HACEK Gram-Negative Bacilli (GNB) IE cases and compare characteristic of IE produced by Enterobacterales and non-fermenting (NF) GNB.

METHODS

From January 2008 to December 2018, 3910 consecutive patients with definitive IE diagnosis, defined with Modified Duke criteria, either clinical or pathological criteria (e.g. demonstration of non-HACEK GNB in valve culture)were prospectively included.

RESULTS

A total of 104 IE cases were caused by non-HACEK GNB (2.6%). Compared to IE due to other microorganisms (excluding HACEK GNB), patients with non-HACEK GNB IE presented with higher age (71 years [IQR 62-78] vs 68 years [IQR: 57-77]; p = 0.026), higher proportion of women (52% vs 31.5%, p < 0.001), higher Charlson Index (5 [IQR: 4-8] vs 4 [IQR 3-7], p = 0.003) and higher in-hospital mortality (36.5% vs 27.1%, p = 0.034). Enterobacterales cases were more frequently associated with genitourinary focus (32.8% vs 5.0%, p = 0.001). NFGNB endocarditis more frequently affected right valves (20.0% vs. 6.3%, p = 0.033), had more common healthcare-related acquisition (67.5% vs. 43.7%, p = 0.030) and venous catheter as focus (40.0% vs. 17.2%, p = 0.019). In the multivariant model, factors related with hospital mortality were: age (OR 1.05, 95%CI 1.00-1.09, p = 0.042), prosthetic valve (OR 2.31, 95%CI 0.90-5.88, p = 0.080), and not performing surgery when indicated (OR 3.60, 95%CI 1.17-11.05, p = 0.025).Patients treated with quinolone combination had lower mortality (OR 0.29; 95%CI 0.09-0.96; p = 0.043).

CONCLUSION

Non-HACEK GNB IE is a rare infection characterized by affecting elderly patients with high comorbidity, nosocomial acquisition and unfavorable outcome. Age, prosthetic valve and not performing surgery when indicated are associated with mortality.

Infective endocarditis caused by Enterobacteriaceae: phenotypic and molecular characterization of Escherichia coli and Klebsiella pneumoniae in Rio de Janeiro, Brazil

The etiological agent for infective endocarditis (IE), a life-threatening disease, is usually gram-positive bacteria. However, gram-negative bacteria can rarely cause IE and 4% of cases are associated with morbidity and mortality. This study aimed to characterize Escherichia coli and Klebsiella pneumoniae isolates from the blood of patients with IE. The characteristics of blood isolates were compared with those of urinary isolates from patients with urinary tract infections (UTIs). The results of this study revealed that K. pneumoniae isolates from patients with IE were phylogenetically related to those from patients with UTI. Additionally, the resistance phenotype, resistance gene, virulence gene, and plasmid profiles were similar between the blood and urinary isolates. The isolates belonging to the sequence types (STs) 76, 36, 101 (K. pneumoniae), and 69 (E. coli) are reported to be associated with drug resistance. The Enterobacteriaceae isolates from patients with IE did not produce extended-spectrum β-lactamase or carbapenemase. Additionally, this study investigated the virulence phenotype, biofilm formation ability, and the ability to adhere to the epithelial cells in vitro of the isolates. The isolates from patients with IE exhibited weaker biofilm formation ability than the urinary isolates. All isolates from patients with IE could adhere to the renal epithelial cells. However, three isolates from patients with UTIs could not adhere to the epithelial cells. The closely related K. pneumoniae isolates (648, KP1, KP2, KP3, and KP4) could not form biofilms or adhere to the epithelial cells. In summary, the molecular analysis revealed that the genetic characteristics of IE-causing K. pneumoniae and E. coli were similar to those of UTI-causing isolates. These isolates belonged to the STs that are considered treatable. Genetically similar isolates did not exhibit the same virulence phenotype. Thus, these non-hypervirulent clones must be monitored as they can cause complex infections in susceptible hosts.

Clinical outcomes of combination versus monotherapy for gram negative non-HACEK infective endocarditis

The objective of this single-center, retrospective cohort study was to identify whether combination therapy is associated with a lower rate of adverse outcomes for the treatment of Gram negative non-HACEK IE. The primary endpoint was a composite of 60-day all-cause mortality, readmission, or recurrence of bacteremia. Of the 60 patients included, 56.7% met the primary composite outcome, with 20% overall mortality at 60 days. There was no difference in the primary composite outcome of 60-day readmission, infection recurrence or mortality between groups, with 62% of patients in the monotherapy group and 50% of patients in the combination therapy group experiencing the composite outcome (P = 0.36). Despite the high mortality and complicated nature of non-HACEK Gram negative IE, this study showed no difference in 60-day bacteremia recurrence, readmission or mortality among patients treated with combination therapy or monotherapy, suggesting that monotherapy may lead to similar clinical outcomes.

Influence of the type of pathogen on the clinical course of infectious complications related to cardiac implantable electronic devices

The specific role of the various pathogens causing cardiac implantable electronic devices-(CIEDs)-related infections requires further understanding. The data of 1241 patients undergoing transvenous lead extraction because of lead-related infective endocarditis (LRIE-773 patients) and pocket infection (PI-468 patients) in two high-volume centers were analyzed. Clinical course and long-term prognosis according to the pathogen were assessed. Blood and generator pocket cultures were most often positive for methicillin-sensitive Staphylococcus aureus (MSSA: 22.19% and 18.13% respectively), methicillin-sensitive Staphylococcus epidermidis (MSSE: 17.39% and 15.63%) and other staphylococci (11.59% and 6.46%). The worst long-term prognosis both in LRIE and PI subgroup was in patients with infection caused by Gram-positive microorganisms, other than staphylococci. The most common pathogens causing CIED infection are MSSA and MSSE, however, the role of other Gram-positive bacteria and Gram-negative organisms is also important. Comparable, high mortality in patients with LRIE and PI requires further studies.

Medically managed prosthetic valve endocarditis caused by Salmonella enteritidis

Infective endocarditis is associated with morbidity and mortality even when appropriately treated. It can be more complicated to treat when prosthetic material is present, often necessitating surgical revision as well as antimicrobial therapy. Endocarditis caused by gram-negative bacilli is a rare occurrence, with some literature and expert opinion suggesting superior outcomes with combined surgery and antibiotics when a prosthetic valve is involved. In cases where the prosthetic valve is well-functioning and undamaged, or cardiothoracic surgery represents a significant operative risk, it can be unclear how best to proceed. This report documents a case of Salmonella enterica subspecies enterica serovar enteritidis endocarditis of a mechanical mitral valve. The patient was managed with 6 weeks of intravenous antibiotics followed by suppressive oral antibiotic therapy. They remain in good health at 24 months.

Elusive Enterobacter cloacae causing pacemaker endocarditis

An 80-year-old patient was admitted for fever, chills, and chest wall pain. He had a past medical history significant for heart failure with a cardiac resynchronization therapy pacemaker implantation. Extensive workup revealed Enterobacter cloacae endocarditis of the pacemaker leads and the mitral valve, a rare etiology with an unidentified source in our patient. He was managed with a rather unconventional method which proved to be successful. This case sheds light on non-HACEK (other than Haemophilus spp., Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, or Kingella spp). gram-negative organisms, and particularly E. cloacae, as uncommon causes of endocarditis with elevated mortality, and discusses potential treatment modalities.

Diagnostic stewardship based on patient profiles: differential approaches in acute versus chronic infectious syndromes

Introduction: New diagnostics may be useful in clinical practice, especially in contexts of high prevalence of multidrug-resistant organisms (MDRO). However, misuse of diagnostic tools may lead to increased costs and worse patient outcome. Conventional and new techniques should be appropriately positioned in diagnostic algorithms to guide an appropriate use of antimicrobial therapy.Areas covered: A panel of experts identified 4 main areas in which the implementation of diagnostic stewardship is needed. Among chronic infections, bone and prosthetic joint infections and subacute-chronic intravascular infections and endocarditis represent common challenges for clinicians. Among acute infections, bloodstream infections and community-acquired pneumonia may be associated with high mortality and require appropriate diagnostic approach.Expert opinion: Diagnostic stewardship aims to improve the appropriate use of microbiological diagnostics to guide therapeutic decisions through appropriate and timely diagnostic testing. Here, diagnostic algorithms based on different patient profiles are proposed for chronic and acute clinical syndromes. In each clinical scenario, combining conventional and new diagnostic techniques is crucial to make a rapid and accurate diagnosis and to guide the selection of antimicrobial therapy. Barriers related to the implementation of new rapid diagnostic tools, such as high initial costs, may be overcome through their rational and structured use.

A fatal case of early prosthetic valve endocarditis caused by multidrug-resistant (MDR) - Sphingomonas paucimobilis

Sphyngomonas paucimobilis (S. paucimobilis) is a low-pathogenicity, gram-negative bacilli (GNB) that are previously known as an opportunist microorganism. Recent studies have shown that S. paucimobilis is an emerging pathogen causing various infections. Multidrug-resistant GNB has emerged as a major clinical and therapeutic dilemma in various hospital-associated infections. Although rare, S. paucimobilis could be associated with infective endocarditis (IE). Prosthetic valve endocarditis (PVE) is the most severe type of IE, which has high mortality rates despite diagnostic and treatment advances. We report a fatal case of early PVE associated with multidrug-resistant (MDR) - S. paucimobilis complicated with perivalvular abscess, complete heart block, valve detachment, and septic arthritis.

Successful treatment of infective endocarditis due to pandrug-resistant Klebsiella pneumoniae with ceftazidime-avibactam and aztreonam

Pandrug-resistant (PDR) K. pneumoniae refractory to conventional treatment has been reported worldwide, causing a huge burden on the healthcare system, patient safety and the economy. K. pneumoniae is a prominent opportunistic pathogen causing hospital-acquired and community-acquired infections, but is rarely associated with infective endocarditis. Currently, there are sparse data guiding the optimal regimen when commonly used antibiotics fail, notably for the treatment of endocarditis infections. Here we report our experience in treating a 40-year-old female with PDR K. pneumoniae infection of cardiovascular implantable electronic device (CIED) and right-sided infective endocarditis. Initial susceptibility testing of the incriminated pathogen showed an apparent susceptibility to colistin but the prolonged course of colistin, gentamicin and meropenem did not resolve the infection. However, the synergistic combinations of aztreonam with ceftazidime-avibactam was able to overcome resistance and clear the infection rapidly. Genome sequencing showed that the PDR K. pneumoniae isolate belongs to the international high-risk clone ST14. The isolate harbored genes encoding NDM-1, OXA-48, CTX-M-14b, SHV-28 and OXA-1, explaining resistance to all β-lactams, including carbapenems. It carried the armA gene conferring resistance to all clinically important aminoglycosides and had alterations in GyrA, ParC and MgrB, explaining resistance to ciprofloxacin and colistin.

Ceftobiprole Perspective: Current and Potential Future Indications

Ceftobiprole combines an excellent spectrum for community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) pathogens, with a low/medium MDR risk, and the β-lactams' safety in frail patients admitted to the hospital in internal medicine wards which may be at high risk of adverse events by anti-MRSA coverage as oxazolidinones or glycopeptides. We aimed to report the available evidence regarding ceftobiprole use in pneumonia and invasive bacterial infections, shedding light on ceftobiprole stewardship. The clinical application and real-life experiences of using ceftobiprole for bloodstream infections, including infective endocarditis, are limited but nevertheless promising. In addition, extended-spectrum ceftobiprole activity, including Enterococcus faecalis, Enterobacteriaceae, and Pseudomonas aeruginosa, has theoretical advantages for use as empirical therapy in bacteremia potentially caused by a broad spectrum of microorganisms, such as catheter-related bacteremia. In the future, the desirable approach to sepsis and severe infections will be administered to patients according to their clinical situation, the intrinsic host characteristics, the susceptibility profile, and local epidemiology, while the "universal antibiotic strategy" will no longer be adequate.

[Antibiotic prophylaxis for infective endocarditis: current approaches]

This review addresses current views on prevention of infectious endocarditis (IE). History of establishing the concept of antibacterial prophylaxis (ABP), major approaches, and substantiation of changes in ABP in recent years are described. Recent international and national guidelines are highlighted, specifically, guidelines of the European Society of Cardiologists, American Heart Association/American College of Cardiology, and the Japanese Circulation Society. The review presents critical evaluation of previously approved international guidelines, including analysis of the effect of partial or complete ABP restriction on IE morbidity and incidence of complications. Special attention is paid to awareness of practitioners, particularly dentists, about ABP issues in their practice. Aspects of validity and key features of preventive approaches in implanting cardiac electronic devices and transcatheter aortic valve implantation are discussed.

Implant-Associated Infections: A Review of the Safety of Cardiac Implants

Cardiac implantations are among the most critical, and life-saving patient management procedures. Most cardiac implantations are performed to correct abnormalities in the conduction and the rhythm of the heart. Because the implants are intended for long-term use ranging from months to years, the failure of an implant is considered a major setback both in the patients as well as surgeons' perspectives. Implant failures can have multifactorial reasons, amongst which infectious causes need to be adequately addressed. This review attempts to evaluate the nature of implants, etiology, predisposing factors, infection control, and preventive strategies for cardiac implant-associated infections.

A review of current treatment strategies for infective endocarditis

INTRODUCTION

Infective endocarditis is one of the most difficult-to-treat infectious diseases.

AREAS COVERED

We restricted this review to the anti-infective treatment of the main bacteria responsible for infective endocarditis, i.e. staphylococci, streptococci, enterococci, and Gram-negative bacilli, including HACEK. Specific topics of major interest in treatment strategy are covered as well, including empirical treatment, oral switch, and treatment duration. We searched in the MEDLINE database to identify relevant studies, trials, reviews, or meta-analyses until May 2020.

EXPERT OPINION

The use of aminoglycosides for the treatment of endocarditis has been dramatically reduced over the last 20 years. It should be administered once daily, and no longer than 2 weeks. For staphylococcal endocarditis, recent data reinforced the role of anti-staphylococcal penicillins, for methicillin-susceptible isolates (alternative, cefazolin), and vancomycin for methicillin-resistant isolates (alternative, daptomycin). For staphylococcal prosthetic-valve endocarditis, these treatments will be reinforced by the addition of gentamicin during the first 2 weeks, and rifampin throughout the whole treatment duration, i.e. 6 weeks. The optimal duration of antibacterial treatment is 4 weeks for most native valve endocarditis, and 6 weeks for prosthetic-valve endocarditis. The oral switch is safe in patients stabilized after the initial intravenous course.

Infective endocarditis by Proteus species: a systematic review

Proteus spp. are members of the Enterobacteriaceae family and are Gram-negative, rod-shaped bacteria known to mainly cause urinary tract infections (UTIs) in humans. However, even though scarce evidence exists suggesting their potential to cause infective endocarditis (IE), a study summarizing the existing evidence is lacking. The purpose of this study was to systemically review all published cases of IE by Proteus species in the literature. A systematic review of PubMed, Scopus and Cochrane Library (through 5^th May 2020) for studies providing epidemiological, clinical and microbiological data as well as data on treatment and outcomes of IE by Proteus species was performed. A total of 16 studies, containing data of 16 patients, were included. A prosthetic valve was present in 25%, while the most common causative pathogen was P. mirabilis. Aortic valve was the most common infected site in 33.3%, followed by mitral valve in 26.7%. Diagnosis was set with transesophageal echocardiography in 37.5%, and transthoracic echocardiography in 25%, while the diagnosis was set at autopsy in 25%. Fever and sepsis were present in 100% and 84.6%, respectively. Aminoglycosides and cephalosporins were the most common antimicrobials used for treatment. Clinical cure was noted in 62.5%, while overall mortality was 43.8%. This systematic review describes IE by Proteus species in detail and provides information on epidemiology, clinical presentation, treatment and outcomes.

Epidemiology and outcomes of non-HACEK infective endocarditis in the southeast United States

Objectives

Infective endocarditis (IE) with non-HACEK Gram-negative (GN) organisms is rare, but associated with poor outcomes. The purpose of this study was to quantify the microbiology, treatment strategies, and frequency of poor outcomes in patients with non-HACEK GN IE.

Materials

Retrospective cohort of adults with definite non-HACEK GN IE from 1/11-1/19. The primary endpoint was poor patient outcome, defined as a composite of all-cause death or infection-related readmission within 90-days of index infection.

Results

43 patients were included: 51% patients were men, and the median (IQR) age was 40 (31–50) years. Forty patients reported injection drug use. The most common organisms were Pseudomonas aeruginosa (68%) and Serratia marcescens (9%). Seventy-six percent of patients received definitive combination therapy; the most common antibiotics used in combination with a β-lactam were aminoglycosides (50%) and fluoroquinolones (34%). Three patients discontinued combination therapy due to toxicity. Twelve-month, all-cause mortality and readmission was 30% and 54%, respectively. In multivariable logistic regression, variables independently associated with composite poor outcome were receipt of fluoroquinolone-based IE combination therapy and septic shock.

Conclusions

Long-term mortality and readmission rates were high. Patients who received fluoroquinolone-based IE combination therapy more frequently developed poor outcomes than those who did not.

Expect the Unexpected: A Rare Case of Pseudomonas aeruginosa Endocarditis

Infective endocarditis (IE) caused by Pseudomonas aeruginosa is extremely uncommon. Reported cases have usually been associated with intravenous drug use, prosthetic heart valves, and/or implanted cardiac devices. Traditionally, successful treatment has necessitated a combination of antimicrobial(s) and valve replacement. Yet, P. aeruginosa IE remains difficult to manage, especially in cases where valve replacement may not be an immediate option. We present such a case of P. aeruginosa IE, highlighting that medical management with 2 antipseudomonal synergistic agents may be an alternative to surgery in particularly complicated cases.

Serratia marcescens and other non-AACEK GNB endocarditis: A case report and review of literature

BACKGROUND

Non-Aggregatibacter aphrophilus, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella spp. (non-AACEK) gram-negative bacilli (GNBs) are an infrequent and challenging cause of endocarditis associated previously with mainly intravenous drug use. Currently, this pathology has increasingly become a healthcare-associated issue. Current guidelines do not clearly define the management of non-AACEK GNB endocarditis due to a lack of prospective trials. We review characteristics, outcomes and treatment of non-AACEK GNB endocarditis, in particular Serratia marcescens endocarditis.

CASE SUMMARY

We describe the case report of a 46-year-old man who presented to the emergency department with high-grade fever and a purulent exudate on an intracardiac device site. Serratia marcescens mitral valve endocarditis as a consequence of complicated generator pocket infection was diagnosed. The patient was treated with complete device removal and a long course of broad-spectrum antibiotics for 6 wk after surgery with intravenous piperacillin-tazobactam and ciprofloxacin, which was later switched to oral ciprofloxacin and sulfamethoxazole-trimethoprim. The patient had complete resolution of symptoms and inflammatory parameters at the end of the treatment and at follow-up.

CONCLUSION

Long-term dual-antibiotic therapy containing a beta-lactam is indicated for most non-AACEK GNB endocarditis, whereas valve surgery may not be necessary in all patients.

Escherichia coli Endocarditis Presenting With Septic Shock in an Immunocompetent Female Patient

Escherichia coli (E. coli) is a rare cause of infective endocarditis, despite being a common cause of bacteremia. E. coli endocarditis affects most frequently immunocompromised elderly women, especially those with diabetes mellitus. We present a case of a 78-year-old female immunocompetent patient, presenting with septic shock and multiple organ dysfunction syndrome. E. coli was isolated in all sets of blood cultures and in urine culture and a contrast-enhanced abdominal computed tomography (CT) scan revealed spleen and left kidney infracts. Transthoracic echocardiography revealed a large (> 15 mm) mobile mass on the atrial side of the posterior mitral valve leaflet. The patient was initially treated with intravenous ceftriaxone and ciprofloxacin for 2 weeks with successful clinical response and clearance of bacteremia, was then subjected to valve replacement (with isolation of E. coli from replaced valve cultures) and continued antibiotic therapy for additional 4 weeks postoperatively. E. coli has emerged in recent years as an important cause of bacteremia, especially in the elderly. In selected patients, as those with persistent Gram-negative bacteremia or severe sepsis/septic shock, echocardiography is of paramount importance for the diagnosis of Gram-negative endocarditis and should be included in our diagnostic algorithm of patient's evaluation.

Prosthetic valve endocarditis caused by Pseudomonas aeruginosa with variable antibacterial resistance profiles: a diagnostic challenge

Background

Infective endocarditis (IE) caused by gram-negative bacilli is rare. However, the incidence of this severe infection is rising because of the increasing number of persons at risk, such as patients with immunosuppression or with cardiac implantable devices and prosthetic valves. The diagnosis of IE is often difficult, particularly when microorganisms such as Pseudomonas aeruginosa, which rarely cause this infection, are involved. One of the mainstays for the diagnosis of IE are persistently positive blood cultures with the same bacteria, while polymicrobial bacteremia usually points to another cause, e.g. an abscess. The antimicrobial resistance profile of some P. aeruginosa strains may change, falsely suggesting an infection with several strains, thus further increasing the diagnostic difficulties.

Case presentation

A 66-year old male patient who had a transcatheter aortic valve implantation (TAVI) one year previously developed fever seven days after an elective inguinal hernia repair. During the following four weeks, P. aeruginosa with different antibiotic resistance profiles was repeatedly isolated from blood cultures. Repeated trans-esophageal echocardiograms (TEE) were negative and an infection by different P. aeruginosa strains was suspected. Extensive diagnostic workup for an infectious focus was performed with no results. Finally, an oscillating mass on the aortic valve was detected by TEE five weeks after the initial positive blood cultures. P. aeruginosa endocarditis was confirmed by culture of the surgically removed valve. Whole genome sequencing of the last two P. aeruginosa isolates (valve and blood culture) revealed identical strains, with genome mutations for AmpR, AmpD and OprD.

Conclusions

The diagnosis of prosthetic valve endocarditis is particularly difficult for several reasons. The modified Duke criteria have a lower sensitivity for patients with prosthetic valve endocarditis and the infection may be caused by “unusual” pathogens such as P. aeruginosa. Patients with repeatedly positive blood cultures should make clinicians suspicious for endocarditis even if imaging studies are negative and if isolated pathogens are “unusual”. Repeatedly positive blood cultures for P. aeruginosa should be considered as “persistent bacteremia” (suspicious for IE) even in the presence of different antibiotic susceptibility patterns, since P. aeruginosa might rapidly activate or deactivate resistance mechanisms depending on antibiotic exposition.

Escherichia coli endocarditis of a native mitral valve

Escherichia coli (E.coli) is a rare cause of endocarditis, although is a common causative agent of bacteremia. An 89-year-old woman presented with recurrent episodes of fever and persistent E. coli bacteremia with 3-month duration, despite antimicrobial therapy. At first, a urinary tract infection was diagnosed and later a mycotic aneurysm of the abdominal aorta was found and required an endovascular repair. The persistence of fever and the evidence of a systolic murmur at the mitral focus raised the suspicion of endocarditis. A transesophageal echocardiogram and a cardiac Magnetic Resonance Imaging (MRI) confirmed the presence of a vegetation at the mitral valve and the patient was treated with ceftriaxone. The presence of comorbid conditions and certain bacterial virulence factors predispose to this rare condition. A high level of suspicion is important to early diagnosis and prompt therapy.

Roseomonas mucosa infective endocarditis in patient with systemic lupus erythematosus: case report and review of literature

Background

Roseomonas mucosa, as a Gram-negative coccobacilli, is an opportunistic pathogen that has rarely been reported in human infections. Here we describe a case of bacteremia in an infective endocarditis patient with systemic lupus erythematosus (SLE).

Case presentations

A 44-year-old female patient with SLE suffered bacteremia caused by Roseomonas mucosa complicated with infective endocarditis (IE). The patient started on treatment with piperacillin-tazobactam and levofloxacin against Roseomonas mucosa, which was switched after 4 days to meropenem and amikacin for an additional 2 weeks. She had a favorable outcome with a 6-week course of intravenous antibiotic therapy.

Discussion and conclusions

Roseomonas mucosa is rarely reported in IE patients; therefore, we report the case in order to improve our ability to identify this pathogen and expand the range of known bacterial causes of infective endocarditis.