Infective endocarditis due to Enterobacter cloacae resistant to third- and fourth-generation cephalosporins

Device-associated aortic valve endocarditis due to a complicated Enterobacter cloacae urinary tract infection

Infective endocarditis (IE) is a life-threatening infection, which has had a notable increase in incidence in recent years. Although Staphylococci or Streptococci are the most common culprit organisms, rarer organisms have also been implicated and associated with a more aggressive disease course. We present a case of Enterobacter cloacae IE affecting the aortic valve in an 82-year-old male with an implantable permanent pacemaker. Our case demonstrates that a prolonged-course of beta-lactam therapy may be an effective, non-invasive management option for IE caused by multidrug-resistant gram-negative organisms.

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.

Infective endocarditis by Enterobacter cloacae: a systematic review and meta-analysis

Enterobacter species are Gram-negative, non-spore-forming, facultative anaerobes typically motile due to the presence of peritrichous flagella. E. cloacae, the species responsible for the majority of Enterobacter infections in humans, is part of the intestinal microbiota and may cause infection in patients that have previously received antimicrobial therapy or who have been admitted to the Intensive Care Unit. E. cloacae may cause several infections, such as pneumonia, urinary tract, skin and soft tissue and intravascular infections. Infective Endocarditis (IE) is a rare disease with notable morbidity and mortality. Even though IE is rarely caused by E. cloacae, these infections can be problematic due to the relative lack of experience in their management. The purpose of this study was to systematically review all published cases of IE by E. cloacae in the literature. A systematic review of PubMed, Scopus and Cochrane library (through 14^th November 2020) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE by E. cloacae was performed. A total of 20 studies, containing data of 20 patients, were included. A prosthetic valve was present in 27.8%. Mitral valve was the commonest infected site, followed by aortic valve. Diagnosis was facilitated by transthoracic and transesophageal echocardiography in 38.5% each, while the diagnosis was set at autopsy in 10%. Fever, sepsis, shock and immunologic phenomena were the most common clinical presentations, followed by heart failure. Aminoglycosides, cephalosporins and carbapenems were the most common antimicrobials used. Clinical cure was noted in 75%, while overall mortality was 30%. Development of shock and treatment with the combination of piperacillin with tazobactam were associated with overall mortality.

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.

Infective endocarditis in patients with liver cirrhosis: a systematic review

Liver cirrhosis is an increasing cause of mortality and morbidity in developed countries. Infective Endocarditis (IE) is an uncommon disease with notable morbidity and mortality. Even though cirrhosis is associated with immune dysfunction and increased occurrence of bacterial infection, IE is infrequently diagnosed in these patients. Thus, the purpose of this study was to systematically review all published cases of IE in patients with cirrhosis in the literature. A systematic review of PubMed, Scopus and Cochrane (through 23^th April 2020) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE in patients with cirrhosis was performed. A total of 78 studies, containing data of 602 patients, were included. A prosthetic valve was present in 17.8%, while the most common causative pathogen was S. aureus in 26% followed by Streptococcus spp in 16.8%. Aortic valve was the most commonly infected site, followed by mitral valve. Diagnosis was set with a transthoracic ultrasound in 55.2%, while the diagnosis was set at autopsy in 16.7%. Fever and heart failure were the most common clinical presentations. Aminoglycosides, vancomycin, and cephalosporins were the antimicrobials most frequently used for treatment. Clinical cure was noted in 68.2%, while overall mortality was 41.4%. This systematic review thoroughly describes IE in patients with liver cirrhosis and provides information on epidemiology, clinical presentation, treatment and outcomes.

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.

Enterobacter Cloacae Device Endocarditis: Case Report, Scoping Study, and Guidelines Review

While traditionally an infection of the endocardial surface of heart valves, infective endocarditis (IE), can atypically present as infection of cardiac implantable electronic devices (CIED), including permanent pacemakers (PPM) or automatic implantable cardioverter-defibrillators (AICD). CIED endocarditis, similar to valvular IE, is generally caused by Gram-positive organisms such as Staphylococcus spp., most frequently S. Auerus, but is rarely caused by gram-negative bacteria, both HACEK and non-HACEK species. We present the case of Enterobacter cloacae CIED endocarditis. We also present a scoping study of previous case reports and case series highlighting the risk factors, surgical interventions, and mortality outcomes associated with E. Cloacae endocarditis. We also discuss the current guidelines and recommendations on antibiotic therapies for non-HACEK Gram-negative endocarditis and surgical management of infected CIED extraction and replacement.

Isolation of Bacteriophages for Clinically Relevant Bacteria

A number of bacteriophages deposited in different culture collections target clinically relevant bacterial hosts. In this chapter, we describe a method for isolating bacteriophage plaques for the most common bacteria involved in nosocomial infections.