DNA Persistence and Relapses Questions on the Treatment Strategies of Enterococcus Infections of Prosthetic Valves

Abstract

We used amplification of the 16S rRNA gene followed by sequencing to evaluate the persistence of bacterial DNA in explanted heart valve tissue as part of the routine work of a clinical microbiology laboratory, and we analyzed the role of this persistence in the relapses observed in our center. We enrolled 286 patients treated for infective endocarditis (IE) who had valve replacement surgery and were diagnosed according to the modified Duke’s criteria described by Li et al. from a total of 579 IE cases treated in our center. The patients were grouped based on the infecting bacteria, and we considered the 4 most common bacterial genus associated with IE separately (144 were caused by Streptococcus spp., 52 by Enterococcus spp., 58 by Staphylococcus aureus and 32 by coagulase-negative Staphylococcus). Based on our cohort, the risk of relapse in patients with enterococcal prosthetic valve infections treated with antibiotics alone was 11%. Bacterial DNA is cleared over time, but this might be a very slow process, especially with Enterococcus spp. Based on a comprehensive review of the literature performed on Medline, most reports still advise combined treatment with penicillin and an aminoglycoside for as long as 4–6 weeks, but there has been no consensus for the treatment of enterococcal infection of prostheses in IE patients.

Impact of Enterococcus faecalis Endocarditis Treatment on Risk of Relapse

“…Studies suggested a higher frequency of relapse among non-operated prosthetic valve-related-endocarditis: 11% to 17.4%, consistent with our 12.8% rate [ 33 , 34 ]. Our data suggest that the presence of a prosthetic valve is not associated with relapse, whereas surgery seems to be the best way to prevent it.…”

Impact of the Hajj on pneumococcal carriage and the effect of various pneumococcal vaccines

“…DNA from Streptococcus spp. seems to be particularly persistent in clinical samples compared to DNA from others bacte- rial species despite appropriate antibiotherapy [36,37]. As an example, DNA can persist for as long as 7 years after the infectious episode in a cardiac valve in a patient with endocarditis.…”

Deglycosylation of Tropheryma whipplei biofilm and discrepancies between diagnostic results during Whipple’s disease progression

“…Conversely, when a WD patient begins antibiotherapy, PCR detection becomes negative soon after treatment. This result is the opposite of the slow clearance of bacterial DNA observed during treatment of infective endocarditis 17 . In contrast, discontinuing treatment for WD is associated quickly with relapse and a positive PCR-based diagnosis 18 .…”