Polymicrobial Infective Endocarditis: Clinical Features and Prognosis

Diagnostic Benefit of Molecular Imaging in Patients Undergoing Heart Valve Surgery for Infective Endocarditis

(1) Background: The successful treatment of infective endocarditis (IE) relies on detecting causative pathogens to administer targeted antibiotic therapy. In addition to standard microbiological cultivation of pathogens from tissue obtained during heart valve surgery, the potential of molecular biological methods was evaluated. (2) Methods: A retrospective study was performed on heart valve tissue from 207 patients who underwent heart valve surgery for IE. FISHseq (fluorescence in situ hybridization combined with 16S rRNA gene PCR and sequencing) was performed in addition to conventional culture-based microbiological diagnostics. The diagnostic performance of FISHseq was compared with the conventional methods and evaluated in the clinical context. (3) Results: Overall, FISHseq provided a significantly higher rate of specific pathogen detection than conventional valve culture (68.1% vs. 33.3%, p < 0.001). By complementing the findings from blood culture and valve culture, FISHseq was able to provide a new microbiological diagnosis in 10% of cases, confirm the cultural findings in 24.2% of cases and provide greater diagnostic accuracy in 27.5% of cases. FISHseq could identify a pathogen in blood-culture-negative IE in 46.2% of cases, while valve culture provided only 13.5% positive results (p < 0.001). (4) Conclusions: This study demonstrates that using FISHseq as an additional molecular biological technique for diagnostics in IE adds substantial diagnostic value, with potential implications for the treatment of IE. It provides pathogen detection, especially in cases where conventional microbiological cultivation is negative or inconclusive.

Bivalvular Endocarditis Due to Polymicrobial Coinfection with Enterococcus faecalis and Coxiella burnetii: A Case Report and Review of the Literature

Polymicrobial endocarditis is uncommon, and polymicrobial endocarditis in combination with Coxiella burnetii is very rare. We herein describe an extremely rare case of polymicrobial bivalvular endocarditis due to coinfection with Enterococcus faecalis and Coxiella burnetii in a 62-year-old male patient, and extensively review the relevant medical literature. To the best of our knowledge, only three similar cases have been previously reported. Q fever is a worldwide endemic bacterial zoonosis, but it and its most common chronic complication, endocarditis, are still underestimated and underdiagnosed worldwide. This situation reflects the paucity of reported cases of polymicrobial endocarditis in combination with Coxiella burnetii. Clinical presentation of Q fever endocarditis is highly nonspecific, and diagnosis may be delayed or missed, leading to severe and potentially fatal disease. Our case and the previously reported similar cases emphasize the need for further evaluation of infective endocarditis due to Coxiella burnetii, in all cases of culture-negative endocarditis, and in prolonged oligo-symptomatic inflammatory syndrome, particularly in the presence of valvular heart disease. This approach should be applied even when typical pathogens are isolated, especially in endemic areas of Q fever, and with atypical presentation.

Triple Threat: Triple Pathogen Endocarditis

Polymicrobial endocarditis is rare but is seen in those with risk factors like diabetes mellitus, structural heart disease, congenital heart defects, prosthetic devices, and intravenous drug use. We report the case of a 30-year-old woman with a past medical history of chronic Hepatitis C and IV drug use who presented with a one-week history of generalized weakness, subjective fevers, lower extremity abscesses, and occasional chest pain. Blood cultures were positive for Streptococcus anginosus, Gemella hemolysans, and Pseudomonas aeruginosa. A transthoracic echocardiogram revealed a very large tricuspid valve vegetation and severe tricuspid regurgitation. Her course was complicated by a complete heart block, septic pulmonary emboli, acute hypoxic respiratory failure, and cardiogenic shock meeting the criteria for early surgical intervention. She underwent an emergency tricuspid valve replacement and pacemaker implantation. During the operation, it became evident that her valve was destroyed with vegetation. A week after the operation, her ejection fraction had improved to 50% and she only exhibited mild tricuspid valve regurgitation. Six weeks later, she was in a stable condition and presented for follow-up. Surgery is necessitated in nearly 50% of Gemella endocarditis cases, 62% of cases with S. anginosus group, and approximately 56% of P. aeruginosa cases. To our knowledge, this is the only case of polymicrobial endocarditis caused by G. hemolysans, S. anginosus, and P. aeruginosa.

A Dual-Pathogen Mitral Valve Endocarditis Caused by Coxiella burnetii and Streptococcus gordonii-Which Came First?

Infective endocarditis (IE) is still a life-threatening disease with high morbidity and mortality. While usually caused by a single bacterium, poly-microbial infective endocarditis (IE) is rare. Here, we report a (blood-culture-negative) dual pathogen mitral valve IE caused by Coxiella burnetii and Streptococcus gordonii: A 53-year-old woman was presented to an internal medicine department with abdominal pain for further evaluation. Within the diagnostic work up, transthoracic echocardiography (TTE) revealed an irregularly shaped echogenic mass (5 × 13 mm) adherent to the edge of the posterior mitral valve leaflet and protruding into the left atrium. As infected endocarditis was suspected, blood cultures were initially obtained, but they remained negative. Chronic Q fever infection was diagnosed using serologic testing. After the occurrence of cerebral thromboembolic events, the patient was admitted for mitral valve surgery. Intraoperatively, a massively destructed mitral valve with adhering vegetations was noted. Examination of the mitral valve by broad-range bacterial polymerase chain reaction (PCR) and amplicon sequencing confirmed Coxiella burnetii infection and yielded Streptococcus gordonii as the second pathogen. Based on the detailed diagnosis, appropriate antibiotic therapy of both pathogens was initiated, and the patient could be discharged uneventfully on the 11th postoperative day after a successful minimal-invasive mitral valve replacement.

Acinetobacter radioresistens and Microbacterium paraoxydans endocarditis in patient with indwelling catheter and metastatic carcinoma

Acinetobacter radioresistens is a rare cause of nosocomial infection and is believed to confer antibiotic resistance to aggressive bacterial species. We present the first reported case of polymicrobial endocarditis caused by A. radioresistens and Microbacterium paraoxydans co-infection, a case of a woman in her late 60s with bacteraemia and ultimate finding of endometrial carcinoma. Bacteraemia with either agent in a previously healthy patient should prompt providers to search for underlying malignancy or immunological problem.We support the use of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry for identifying these organisms in cultures, as well as the development of faster isolation techniques through PCR. Furthermore, we advocate for providers to order early antibiotic susceptibility testing, since our patient's Microbacterium sp was not susceptible to meropenem unlike most Microbacterium reported in literature.

Effect of Sonication on Microwave Inactivation Kinetics of Enterococcus faecalis in Dairy Effluent

The aim of this study is to inactivate Enterococcus faecalis ATCC 29212 present in dairy wastewater effluent using microwave (MW) waves and/or ultrasound waves (US). The ultrasonic bath treatment (35 kHz) had no significant effect on the reduction of the survival rate (predominant declumping effect). At 650 W of microwave treatment, the total destruction was completed at 75 s, while at 350 W a 3 log reduction was achieved. The Weibull model was fitted to the survival curves to describe the inactivation kinetics, and the effect of the combined microwave-ultrasound treatments was evaluated. The scaling parameter α that was estimated from the inactivation kinetics for the microwaves combined with the ultrasound waves in pre-treatment was found to be lower than the scaling parameters obtained in post-treatment, which were in turn lower than those estimated for microwaves or ultrasound waves alone. The use of the ultrasound waves in pre-treatment was more effective than in post-treatment; a total reduction was achieved using a combination of US (30 min) followed by MW (650 W) with α = 28.3 s, while 4.0 log was obtained by reversing all processes with α = 34.5 s. The results from the protein assays indicate that the bacterial wall was damaged and that holes were formed from which protein leakage occurred.

An 82-year-old man with a prosthetic aortic valve and multimicrobial bacteremia

The patient is an 82-year-old male with a past medical history of aortic valve replacement who presented to the emergency department after a fall. He developed atrial fibrillation with a rapid ventricular response and non-ST-segment-elevation myocardial infarction, leading to hospitalization. During hospital admission, the patient complained of midline thoracic back pain, and an extensive evaluation for this complaint revealed discitis and osteomyelitis with epidural abscess near the T7 and T8 vertebrae that did not result in neurological deficits and required no surgical intervention. A total of 2 blood cultures were reported positive for Actinomyces naeslundii, Streptococcus mitis, Streptococcus oralis, and Abiotrophia defectiva. A transesophageal echocardiogram showed a small vegetation on the aortic prosthetic valve with probable small vegetation on the mitral valve. He was prescribed ceftriaxone intravenously for 12 weeks, followed by amoxicillin 2 g orally twice a day for at least 12 months. A. naeslundii is not commonly known to cause infective endocarditis, whereas S. mitis, S. oralis, and A. defectiva have been reported to do so. One previous case of A. naeslundii was reported to cause prosthetic valve endocarditis as a single infectious agent. To our knowledge, this is the first case report for A. naeslundii as part of multimicrobial bacteremia leading to endocarditis, discitis, and osteomyelitis.

Polymicrobial native valve endocarditis due to Bacillus cereus and Cardiobacterium hominis

We present a case of polymicrobial subacute bacterial endocarditis and bacteremia with Bacillus cereus and Cardiobacterium hominis in a 72-year-old man with pre-existing mitral valve disease and prior mitral valve repair who presented with renal failure and glomerulonephritis. Bacillus is often a contaminant in blood cultures but has been rarely implicated in patients with invasive infections such as endocarditis. Intravenous drug use, prosthetic heart valves, valvular heart disease and venous catheters are the most frequently described risk factors for Bacillus bacteremia and endocarditis in the medical literature. Management is challenging as Bacillus is resistant to penicillin and cephalosporin antibiotics due to production of beta-lactamase. Polymicrobial endocarditis is uncommon and when it occurs typically involves Staphylococcal species. To our knowledge, this is the first reported case of polymicrobial endocarditis in which both Bacillus and a HACEK organism are implicated.

Disseminated Native Tricuspid Valve Infective Endocarditis and Vertebral Osteomyelitis Secondary to Veillonella dispar in a Patient Who Injects Drugs

We present the case of a 50-year-old man presenting with fever, back pain, persistent bacteremia with Veillonella dispar, echocardiographic evidence of a tricuspid valve vegetation increasing in size, and magnetic resonance imaging suggesting new vertebral osteomyelitis. He was successfully treated with intravenous ceftriaxone for six weeks. Deep-seated infections secondary to Veillonella species are rare, but cases of endocarditis, osteomyelitis, and meningitis have been reported in the literature. Given Veillonella species are normal human commensals present in the oropharyngeal flora, we suspect our patient developed native tricuspid valve endocarditis and vertebral osteomyelitis as a complication of either poor dentition or contaminated injection drug use paraphernalia and subsequent hematogenous seeding.

An unusual case of infective endocarditis with acute limb ischemia and cardiac embolism

Infective endocarditis (IE) is a persistent health issue, particularly among intravenous drug users. We discussed a case of infective endocarditis in a patient who uses IV drugs, which had some unusual features such as unusual presentation, polymicrobial infection, left-sided valve involvement, coronary embolism, and an uncommon pathogen for IE.

Difficult to Treat Infections in the Burn Patient

Background: Unusual infections can lead to complications in more severely burned patients and pose major challenges in treatment. Methods: The published literature of retrospective reviews and case series of the uncommon infections of osteomyelitis, polymicrobial bacteremia, recurrent bacteremia, endocarditis, central nervous system (CNS), and rare fungal infections in burned patients have been summarized and presented. Results: When compared with infections occurring in the non-burn population, these infections in burn patients are more likely to be because of gram-negative bacteria or fungi. Because of hyperdynamic physiology and changes in immunomodulatory response secondary to burns, the clinical presentation of these infections in a patient with major burns differs from that of the non-burn patient and may not be identified until the post-mortem examination. Some of these infections (osteomyelitis, endocarditis, CNS, rare fungal infections) may necessitate surgical intervention in addition to antimicrobial therapy to achieve cure. The presence of the burn and allograft can also present unique challenges for surgical management. Conclusions: These difficult and unusual infections in the severely burned patient necessitate an index of suspicion, appropriate diagnosis, identification and sensitivities of the putative pathogen, effective systemic antimicrobial therapy, and appropriate surgical intervention if recovery is to be achieved.

Q Fever and Kingella kingae Endocarditis in a Toddler: A Rare Coinfection Case

A toddler after tetralogy of Fallot graft repair in infancy was diagnosed with endocarditis. Blood cultures were positive for Kingella kingae and serology was positive Coxiella burnetii. He was treated medically and surgically. A postoperative specimen polymerase chain reaction confirmed a coinfection. A comprehensive patient history was imperative for identification of an unlikely infection at this age.

Clinical predictors and outcome impact of community-onset polymicrobial bloodstream infection

OBJECTIVES

Very few studies have characterised community-onset polymicrobial bloodstream infections (BSIs). This study determined the incidence, risk factors, and outcomes of polymicrobial BSI as compared with monomicrobial BSI in a cohort of patients with community-onset BSIs.

METHODS

This prospective cohort study enrolled consecutive patients with laboratory confirmed BSIs who were admitted to two tertiary emergency departments in Taiwan between 1 January 2015 and 31 December 2016. It assessed the independent impact of polymicrobial BSIs on survival by a propensity score weighting method. Subsequently, independent clinical predictors were identified with multivariate logistic regression model analysis with internal validation by 10-fold cross validation.

RESULTS

Among 1166 patients with community-onset BSI, 133 (10.9%) episodes of polymicrobial BSIs occurred. Anaerobe, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus spp., and Candida spp. were the most common isolated microorganisms in polymicrobial BSI. Polymicrobial BSIs were associated with an increased 90-day mortality rate (OR 2.20, 95% CI 1.98-2.60). A prediction model was built to predict polymicrobial BSI with moderate predictability (c statistic = 0.78). Significant predictors included biliary tract infection, nosocomial infection, nursing home residence, stroke, and afebrile presentation.

CONCLUSIONS

Polymicrobial BSI occurred in approximately 1 in 10 episodes of community-onset BSI and was independently associated with excess mortality. Clinical predictors identified in this study may help guide the prescription of empiric broad-spectrum antibiotics.

Prognostic factors of mortality after surgery in infective endocarditis: systematic review and meta-analysis

PURPOSE

There is a lack of consensus about which endocarditis-specific preoperative characteristics have an actual impact over postoperative mortality. Our objective was the identification and quantification of these factors.

METHODS

We performed a systematic review of all the studies which reported factors related to in-hospital mortality after surgery for acute infective endocarditis, conducted according to PRISMA recommendations. A search string was constructed and applied on three different databases. Two investigators independently reviewed the retrieved references. Quality assessment was performed for identification of potential biases. All the variables that were included in at least two validated risk scores were meta-analyzed independently, and the pooled estimates were expressed as odds ratios (OR) with their confidence intervals (CI).

RESULTS

The final sample consisted on 16 studies, comprising a total of 7484 patients. The overall pooled OR were statistically significant (p < 0.05) for: age (OR 1.03, 95% CI 1.00-1.05), female sex (OR 1.56, 95% CI 1.35-1.81), urgent or emergency surgery (OR 2.39 95% CI 1.91-3.00), previous cardiac surgery (OR 2.19, 95% CI 1.84-2.61), NYHA ≥ III (OR 1.84, 95% CI 1.33-2.55), cardiogenic shock (OR 4.15, 95% CI 3.06-5.64), prosthetic valve (OR 1.98, 95% CI 1.68-2.33), multivalvular affection (OR 1.35, 95% CI 1.01-1.82), renal failure (OR 2.57, 95% CI 2.15-3.06), paravalvular abscess (OR 2.39, 95% CI 1.77-3.22) and S. aureus infection (OR 2.27, 95% CI 1.89-2.73).

CONCLUSIONS

After a systematic review, we identified 11 preoperative factors related to an increased postoperative mortality. The meta-analysis of each of these factors showed a significant association with an increased in-hospital mortality after surgery for active infective endocarditis. Graph summary of the Pooled Odds Ratios of the 11 preoperative factors analyzed after the systematic review and meta-analysis.

Bacterial infiltration in structural heart valve disease

OBJECTIVES

The pathology of structural valvular heart disease (sVHD) ranges from basic diseases of rheumatologic origin to chronic degenerative remodeling processes after acute bacterial infections. Molecular genetic methods allow detection of the complete microbial spectrum in heart valve tissues independent of microbiological cultivation. In particular, whole-metagenome analysis is a sensitive and highly specific analytical method that allows a deeper insight into the pathogenicity of the diseases. In the present study we assessed the pathogen spectrum in heart valve tissue from 25 sVHD patients using molecular and microbiological methods.

METHODS

Twenty-five sVHD patients were selected randomly from an observational cohort study (March 2016 to January 2017). The explanted native heart valves were examined using microbiological methods and immunohistological structural analysis. In addition, the bacterial metagenome of the heart valve tissue was determined using next-generation sequencing.

RESULTS

The use of sonication as a pretreatment of valve tissue from 4 sVHD patients permitted successful detection of Clostridium difficile, Enterococcus faecalis, Staphylococcus saccharolyticus, and Staphylococcus haemolyticus using microbial cultivation. Histological staining revealed intramural localization. Metagenome analysis identified a higher rate of bacterial infiltration in 52% of cases. The pathogen spectrum included both gram-positive and gram-negative bacteria.

CONCLUSIONS

Microbiological and molecular biological studies are necessary to detect the spectrum of bacteria in a calcified heart valve. Metagenome analysis is a valid method to gain new insight into the polymicrobial pathophysiology of sVHD. Our results suggest that an undetected proportion of sVHD might be triggered by chronic inflammation or influenced by secondary bacterial infiltration.

Right-sided infective endocarditis in patients with uncorrected ventricular septal defect and patent ductus arteriosus: Two case reports

Uncorrected left-to-right shunt congenital heart defect is a predisposing factor for infective endocarditis (IE), especially right-sided IE which has different clinical manifestations and complications from left-sided IE. Prompt diagnosis by means of transthoracic echocardiography and timely antibiotics management for IE are encouraged to prevent multiorgan failure and fatal pulmonary embolism.

Native valve dual pathogen endocarditis caused by Burkholderia cepacia and Aspergillus flavus - a case report

Introduction

Infective endocarditis (IE) is an important clinical condition with significant morbidity and mortality among the affected population. A single etiological agent is identifiable in more than 90 % of the cases, however, polymicrobial endocarditis (PE) is a rare find, with a poor clinical outcome. Here we report a case of native valve dual pathogen endocarditis caused by Burkholderia cepacia and Aspergillus flavus in an immunocompetent individual. It is among unique occurrences of simultaneous bacterial and fungal etiology in IE.

Case presentation

A 30-year-old male was admitted to a cardiology institute with complaints of low grade intermittent fever and progressive shortness of breath for last two months. He was a known case of rheumatic heart disease and had suffered an episode of IE three years ago. On the basis of clinical presentation and the results of radiological investigations, a diagnosis of infective endocarditis was made. Paired blood samples for culture and sensitivity, sampled before the commencement of antimicrobial therapy, yielded growth of Burkholderia cepacia which was highly drug resistant. Sensitivity results-directed therapy consisting of tablet Trimethoprim–Sulfamethoxazole, two double-strength tablets 12 hourly, and Meropenem, 1 g IV every 8 h, was commenced. Despite mild relief of fever intensity, overall clinical condition did not improve and double valve replacement therapy was carried out. Excised valves were sent for microbiological analysis. Burkholderia cepacia was grown on tissue culture with a similar antibiogram to that previously reported from the blood culture of this patient. Direct microscopy of section of valvular tissue with 10 % KOH revealed abundant fungal hyphae. Patient serum galactomannan antigen assay was also positive. Histopathological examination of vegetations also revealed hyphae typical of species of the genus Aspergillus. The patient was successfully treated with meropenem, trimethoprim–sulfamethoxazole and voriconazole.

Conclusion

The hallmark of successful treatment in this case was exact identification of pathogens, antibiogram-directed therapy and good liaison between laboratory experts and treating clinicians.

Model systems for the study of Enterococcal colonization and infection

Enterococcus faecalis and Enterococcus faecium are common inhabitants of the human gastrointestinal tract, as well as frequent opportunistic pathogens. Enterococci cause a range of infections including, most frequently, infections of the urinary tract, catheterized urinary tract, bloodstream, wounds and surgical sites, and heart valves in endocarditis. Enterococcal infections are often biofilm-associated, polymicrobial in nature, and resistant to antibiotics of last resort. Understanding Enterococcal mechanisms of colonization and pathogenesis are important for identifying new ways to manage and intervene with these infections. We review vertebrate and invertebrate model systems applied to study the most common E. faecalis and E. faecium infections, with emphasis on recent findings examining Enterococcal-host interactions using these models. We discuss strengths and shortcomings of each model, propose future animal models not yet applied to study mono- and polymicrobial infections involving E. faecalis and E. faecium, and comment on the significance of anti-virulence strategies derived from a fundamental understanding of host-pathogen interactions in model systems.

The relationship between causative microorganisms and cardiac lesions caused by infective endocarditis: New perspectives from the contemporary cohort of patients

BACKGROUND

The etiology of infective endocarditis (IE) is changing. More aggressive forms with multiple IE cardiac lesions have become more frequent. This study sought to explore the relationship between contemporary causative microorganisms and IE cardiac lesions and to analyze the impact of multiple lesions on treatment choice.

METHODS

In 246 patients hospitalized for IE between 2008 and 2015, cardiac lesions caused by IE were analyzed by echocardiography, classified according to the 2015 European Society of Cardiology guidelines and correlated with microbiological data. We defined a new parameter, the Echo IE Sum, to summarize all IE cardiac lesions in a single patient, enabling comprehensive comparisons between different etiologies and treatment strategies.

RESULTS

Staphylococcus aureus was associated with the development of large vegetation (OR 2.442; 95% CI 1.220-4.889; p=0.012), non-HACEK bacteria with large vegetation (OR 13.662; 95% CI 2.801-66.639; p=0.001), perivalvular abscess or perivalvular pseudoaneurysm (OR 5.283; 95% CI 1.069-26.096; p=0.041), and coagulase-negative staphylococci (CoNS) with leaflet abscess or aneurysm (OR 3.451; 95% CI 1.285-9.266, p=0.014), and perivalvular abscess or perivalvular pseudoaneurysm (OR 4.290; 95% CI 1.583-11.627; p=0.004). The Echo IE Sum significantly differed between different etiologies (p<0.001), with the highest value in non-HACEK and the lowest in streptococcal endocarditis. Patients operated for IE had a significantly higher Echo IE Sum vs those who were medically treated (p<0.001).

CONCLUSION

None of the IE cardiac lesions is microorganism-specific. However, more severe lesions were caused by S. aureus, CoNS, and non-HACEK bacteria. The highest propensity to develop multiple lesions was shown by the non-HACEK group. Higher Echo IE Sum in patients sent to surgery emphasized the importance of multiple IE cardiac lesions on treatment choice and potential usage of Echo IE Sum in patient management.

Infective Endocarditis in French West Indies: A 13-Year Observational Study

We conducted an observational study to describe the characteristics of infective endocarditis (IE) in French West Indies (FWI) and to identify variables associated with in-hospital case fatality. The records of the patients admitted for IE to the University Hospital of Martinique between 2000 and 2012 were collected using an electronic case report form. Only Duke-Li definite cases were considered for this analysis. Variables associated with in-hospital mortality were tested using univariate logistic regression analysis. The analysis included 201 patients (median age 58 years, sex ratio: two males to one female). There was no previously known heart disease in 45.8%, a prosthetic valve in 21.4%, and previously known native valve disease in 32.8% of the cases. Community-acquired IE represented 59.7% of all cases, health-care-associated IE represented 38.3% and injection-drug-use-acquired IE represented 1.5%. Locations of IE were distributed as follows: 42.3% were mitral valve IE, 34.8% were aortic valve IE, and 7% were right-sided IE. Microorganisms recovered from blood cultures included 30.4% streptococci, 28.9% staphylococci, and 5% enterococci. Blood cultures were negative in 20.9% of the cases. Surgical treatment was performed in 53% of the patients. In-hospital case fatality rate was 19%. Advanced age, Staphylococcus aureus IE, and health-care-associated IE were associated with in-hospital case fatality. The epidemiological and microbiological profile of IE in FWI is in between those observed in developed countries and developing countries: patients were younger, blood cultures were more frequently negative, and IE due to group D streptococci and enterococci were less common than in industrialized countries.

First report of Sneathia sanguinegens together with Mycoplasma hominis in postpartum prosthetic valve infective endocarditis: a case report

BACKGROUND

The presence of more than one bacterial agent is relatively rare in infective endocarditis, although more common in prosthetic cases. Molecular diagnosis from a removed heart tissue is considered a quick and effective way to diagnose fastidious or intracellular agents.

CASE PRESENTATION

Here we describe the case of postpartum polymicrobial prosthetic valve endocarditis in a young woman. Sneathia sanguinegens and Mycoplasma hominis were simultaneously detected from the heart valve sample using broad range 16S rRNA polymerase chain reaction (PCR) followed by sequencing while culture remained negative. Results were confirmed by independent PCR combined with denaturing gradient gel electrophoresis. Before the final agent identification, the highly non-compliant patient left from the hospital against medical advice on empirical intravenous treatment with aminopenicillins, clavulanate and gentamicin switched to oral amoxycillin and clavulanate. Four months after surgery, no signs of inflammation were present despite new regurgitation and valve leaflet flail was detected. However, after another 5 months the patient died from sepsis and recurrent infective endocarditis of unclarified etiology.

CONCLUSIONS

Mycoplasma hominis is a rare causative agent of infective endocarditis. To the best of our knowledge, presented case is the first report of Sneathia sanguinegens detected in this condition. Molecular techniques were shown to be useful even in polymicrobial infective endocarditis samples.

Endocarditis caused by anaerobic bacteria

BACKGROUND

Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES).

METHODS

We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria).

RESULTS

Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%).

CONCLUSION

IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms.