Clinical and microbiological features of infective endocarditis caused by aerococci

Abstract

Aerococci are increasingly recognized as causative agents in human infective endocarditis (IE). Information on the clinical presentation and the prognosis of IE caused by aerococci is limited. We employed the Swedish Registry of Infective Endocarditis (SRIE) to identify cases of aerococcal IE. The medical records were analysed and comparisons with cases of IE caused by other pathogens reported to the SRIE were made. Available bacterial isolates were reanalysed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) and the aetiology was confirmed to be Aerococcus urinae in fourteen cases and Aerococcus sanguinicola in two cases. The bacteria were sensitive to penicillin and Etest-based synergy testing and time-kill experiments suggested synergy between penicillin and gentamicin towards some isolates. The patients had a median age of 79 years, which was significantly higher than that of patients with IE caused by streptococci or Staphylococcus aureus. Most patients with IE caused by aerococci had underlying urinary tract diseases and many presented with symptoms suggesting a urinary tract focus of the infection. Despite the fact that many patients with aerococcal IE presented with severe sepsis, ICU treatment was needed only in one patient and there was no fatality. Valve exchange surgery was needed in four of sixteen patients with aerococcal IE and embolization was seen in three patients. This report is by far the largest on aerococcal IE and suggests that the prognosis of aerococcal IE is relatively favourable despite the fact that the patients are old and have significant comorbidities.

A rare case of aerococcus urinae infective endocarditis

“…However, a recent Swedish study by Sunnerhagen et al . demonstrates a favorable prognosis despite even in patients with advance age and significant comorbidities [19]. The authors in that study also suggest better prognosis compared to IE from Staphylococcus aureus in terms of mortality and frequency of embolization [19].…”

“…Of the 42 cases currently accounted in published literature (excluding the current case) 15 fatalities (35.71%) have been reported [7,19–21]. However, a recent Swedish study by Sunnerhagen et al .…”

Clinical presentation of infective endocarditis caused by different groups of non-beta haemolytic streptococci

“…We have previously used the SRIE to describe the features of aerococcal IE [17] and here we employ the SRIE to identify cases of IE with streptococci. We group the bacteria using MALDI-TOF MS and compare clinical features of IE caused by different streptococcal groups.…”

Aerococcus urinae – A potent biofilm builder in endocarditis

“…Differentiation between these two genera is possible by hippurate hydrolysis testing or sequencing of the 16S rRNA gene [5,21,22]. Since 2013, MALDI-TOF (matrixassisted laser desorption ionization time-of-flight mass spectrometry) has also played a major role in the identification from clinical samples of A. urinae [23,24].…”