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.