Naslov
Towards better understanding and management of Propionibacterium acnes in cases of prosthetic valve endocarditis

Autori
Meštrović, Tomislav ; Profozić, Zora ; Neuberg, Marijana

Izvornik
Interactive Cardiovascular and Thoracic Surgery (1569-9293) 23 (2016), 1; 154-155

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, pismo uredniku, stručni

Ključne riječi
prosthetic valve endocarditis, propionibacterium acnes

Sažetak
We read with great interest the paper by van Valen and his colleagues evaluating patients with prosthetic valve endocarditis (PVE) caused by an opportunistic bacterial pathogen: Propionibacterium acnes (P. acnes) [1]. The authors should be congratulated for publishing the largest single-centre series to date on the topic, as thus far the literature was dominated by single case reports. Their work will undoubtedly help increase appreciation for this often-neglected etiology of endocarditis. We would like to add some thoughts on the microbiological aspects of PVE caused by this facultative anaerobic species. Diagnosis of PVE caused by this micro-organism is often delayed due to oligosymptomatic and non-specific presentation, hence microbiological confirmation is pivotal for directing treatment. Unfortunately, aside for establishing positivity of blood and/or tissue cultures, no further elaboration was given on the microbiological techniques employed to diagnose P. acnes in this study, probably due to its retrospective design. From a clinical perspective, it would also be interesting to know the incidence of neurological symptoms in this case series of 13 patients, as these are more commonly observed in P. acnes PVE than in any other type of infective endocarditis [2]. In the discussion the authors rightfully emphasize that the diagnosis is cumbersome due to the prolonged incubation time of P. acnes (up to two weeks). Recently it has been shown that a technique that combines polymerase chain reaction (PCR) with an electrospray ionization mass spectrometry can be applied to heart valves and prosthetic material to diagnose P. acnes with increased sensitivity and speed when compared to culture methods [3]. Still, one has to bear in mind the expensive equipment and cost-effectiveness issues of adding such technology to the diagnostic armamentarium. The authors further state that there is still no clear explanation why cardiac valve infections (but also infections of osteo-articular prostheses) caused by this pathogen are more frequent in men than women. Interestingly, Patel et al. conducted a study of P. acnes colonization of the human shoulder, which revealed higher prevalence and bacterial burden of P. acnes in men [4]. Although the exact reasons for such disparity are still unknown, we hypothesize that studies of other body sites would yield similar findings, inevitabley resulting in more frequent PVE and other infections in the male gender. Antibiotic therapy of patients in this study primarily consisted of penicillin (with or without rifampicin) for six weeks after surgery, which is a treatment scheme recommended by some other authors as well. Nevertheless, longer treatment periods (up to six months) were also described in the literature - some of them even resulting in a successful treatment of patients with P. acnes PVE without surgical approach [5]. Although the rationale for including rifampicin in the therapy regimen is the purported effect on P. acnes biofilm, randomized-controlled studies are necessary to confirm its true clinical value (as has been conducted for staphylococcal implant-associated infections).

Izvorni jezik
Engleski

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