Emphysematous endocarditis caused by AmpC beta-lactamase-producing Escherichia coli: A case report

An enigmatic presentation of Escherichia coli endocarditis: Emphasizing the role of brain magnetic resonance imaging

Key Clinical Message

Infective endocarditis should be considered in any febrile individual with acute onset neurological symptoms. If suspicion is high, a negative brain computed tomography does not virtually exclude embolism, and magnetic resonance imaging is warranted.

Abstract

A diagnosis of infective endocarditis (IE) is often delayed, particularly in those infected with unusual organisms. Hereby, we report a case of a female patient presented with dysarthria, confusion, and altered mental status after being treated for Escherichia coli bacteremia. Computed tomography of the brain was unrevealing; however, scattered embolic phenomena were visualized on magnetic resonance imaging (MRI). The case underscores the importance of clinical awareness, particularly in the setting of unusual microorganisms, and the role of brain MRI in the diagnosis of IE.

Native valve emphysematous enterococcal endocarditis: expanding the differential diagnosis

INTRODUCTION

Emphysematous endocarditis is caused by the gas-forming organisms Citrobacter koseri, Escherichia coli, Clostridium species, and Finegoldia magna. We report the first case of emphysematous endocarditis caused by Enterococcus faecalis.

CASE REPORT

An 82-year-old man presented with fever and rapidly progressive shortness of breath. He was found to be in atrial fibrillation with rapid ventricular rates. Two-dimensional transthoracic echocardiography demonstrated severe mitral regurgitation. Subsequent two- and three-dimensional transesophageal echocardiogram revealed a large, highly mobile vegetation on the atrial surface of the anterior mitral leaflet with aneurysmal destruction of the lateral scallop requiring mitral valve replacement. Sequencing of the vegetation revealed Enterococcus faecalis, an anaerobic gram-positive coccus that, in rare cases, produces gas using a heme-dependent catalase. Histopathological analysis of the infected valve suggested interstitial gas accumulation, leading to the diagnosis of emphysematous endocarditis.

CONCLUSIONS

E. faecalis-associated emphysematous endocarditis should be included in the differential diagnosis of valvular vegetation in patients with a rapidly progressing clinical course. When possible, histopathological analysis should be used alongside other imaging techniques to confirm the diagnosis of emphysematous endocarditis. This case also highlights the importance of collecting blood cultures prior to initiating antibiotic treatment.

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.

The causal relationship between O2:K7:H6 extra-intestinal pathogenic Escherichia coli (ExPEC) and native valve endocarditis: a case report

Background

Native valves infective endocarditis due to Escherichia coli is still a rare disease and a particular virulence of some E.coli isolate may be suspected.

Case presentation

A 79-year-old woman presented during the post-operative period of an orthopedic surgery a urinary tract infection following obstructive ureteral lithiasis. E. coli was isolated from a pure culture of urine and blood sampled simultaneously. After evidence of sustained E.coli septicemia, further investigations revealed acute cholecystitis with the same micro-organism in biliary drainage and a native valve mitral endocarditis. E.coli was identified as O2:K7:H6, phylogenetic group B2, ST141, and presented several putative and proven virulence genes. The present isolate can be classified as both extra-intestinal pathogenic E.coli (ExPEC_JJ) and uropathogenic E. coli (UPEC_HM).

Conclusions

The relationship between the virulent factors present in ExPEC strains and some serotypes of E. coli that could facilitate the adherence to cardiac valves warrants further investigation.

Extended spectrum beta lactamase producing Escherichia coli tricuspid valve endocarditis

Escherichia coli is a rare cause of endocarditis. This article reports an 82-year-old male with a mechanical aortic valve replacement who was admitted for fever and fatigue. He was diagnosed with a tricuspid valve endocarditis caused by an extended spectrum beta lactamase producing Escherichia coli following positive blood cultures and echocardiography. He received six weeks of imipenem / cilastatin and subsequently improved and was discharged with ambulatory follow ups with his infectious disease specialist.

Native valve endocarditis due to Escherichia coli infection: a case report and review of the literature

Background

Infective endocarditis due to Escherichia coli is a rare disease but is increasing in frequency, especially among older women. In addition, its mortality rate is higher than that of endocarditis due to the HACEK-group gram-negative bacteria (Haemophilus spp., Aggregatibacter spp., Cardiobacterium hominis, Eikenella corrodens, and Kingela spp.).

Case presentation

A 58-year-old Japanese woman with a history of alcohol abuse was admitted to our hospital because of a fever. She was diagnosed with infective endocarditis due to E. coli based on repeated blood cultures and transthoracic echocardiography, which revealed vegetations attached to the anterior leaflet and chordae tendineae of the mitral valve. Despite administration of sulbactam/ampicillin and gentamycin, she developed purulent spondylitis during hospitalization and required treatment with meropenem administration for 6 weeks, leading to resolution of the endocarditis. She took oral levofloxacin for 2 months, and the spondylitis was completely cured 7 months after discharge.

Conclusion

Escherichia coli affects native valves without degenerative valvulopathy rather than prosthetic valves, especially in patients with risk factors such as an immunosuppressive status, excessive alcohol consumption, or treatment with hemodialysis. Peripheral embolization, congestive heart failure, and valve-ring abscesses are major complications of E. coli endocarditis; notably, infective myocarditis can also occur. The mortality and surgical intervention rates are 21% and 42%, respectively. Physicians should be cognizant of the necessity of surgical intervention when E. coli endocarditis is resistant to antibiotic therapy.