The Brief Case: An Unusual Cause of Infective Endocarditis after a Urological Procedure

KEYWORDS Actinotignum schaalii, endocarditis, urinary tract infection, urinalysis, mass spectrometry, blood culture, infective endocarditis CASE A 63-year-old man who underwent transurethral resection of the prostate for benign prostatic hyperplasia presented to his primary care physician for fever and shortness of breath 3 weeks following the procedure. He became apyretic with a moderate improvement of dyspnea after an empirical 7-day course of amoxicillin. Two weeks later, the patient underwent a colonoscopy for rectal bleeding, which revealed only hemorrhoids. One week later, he complained of increasing dyspnea. Cardiac ausculta-tion revealed an aortic diastolic murmur. Transthoracic echocardiography revealed a grade 3 aortic regurgitation and a vegetation of 2 by 2 cm on the tricuspid valve. Subsequently, the patient was admitted to the cardiology ward of the University Hospital of Nancy for infective endocarditis. He underwent tricuspid and aortic valve replacement with bioprosthetic valves because of acute heart failure. One of the three sets of blood cultures (Becton Dickinson, Le Pont de Claix, France) obtained at admission was positive for Gram-positive bacilli that grew in aerobic and anaerobic bottles after 64 and 37 h of incubation, respectively. After subcultures on tryptic soy agar with 5% sheep blood (TSS) (bioMerieux, Marcy l'Etoile, France) at 37°C in 5% CO 2 atmosphere, isolates were identified by the use of a Vitek mass spectrometry (MS) system (bioMerieux; database version 3.0) as Actinotignum schaalii (confidence level of Ն99.9%). A systematic examination of the urine, performed at admission, revealed the presence of 10 5 leukocytes/ml. Urine culture, performed using a nonselective chromogenic agar for nonfastidious uropathogens (UriSelect 4; Bio-Rad, Marnes-la-Coquette, France) and incubated at 37°C aerobically, yielded amoxicillin-susceptible Escherichia coli at 10 3 CFU/ml. In order to identify the potential portal of entry of A. schaalii, the urine sample obtained prior to antibiotic therapy and stored at 4°C in tubes with preservative (BD Vacutainer with buffered boric acid) for approximately 84 h was reinoculated on selective Columbia colistin and nalidixic acid (CNA) blood agar (bioMerieux) under anaerobic conditions at 37°C. After 48 h of incubation, A. schaalii was detected at 10 3 CFU/ml. Fresh valvular specimens taken during surgery were processed using standard methods and inoculated on Columbia agar with 5% sheep blood (COS), chocolate agar with PolyViteX (PVX), and TSS agar (bioMerieux) as well as into Schaedler broth supplemented with vitamin K (bioMerieux). All media were incubated at 37°C aerobi-cally (Schaedler broth), aerobically with 5% CO 2 (TSS, PVX), or anaerobically (COS). Gross examination of the tricuspid valve specimen confirmed the presence of a vegetation. Rare branched Gram-positive bacilli were seen on Gram stains of ground valvular Citation Diallo K, Ferrand J, Goehringer F, Selton-Suty C, Folliguet T, Alauzet C, Lozniewski A. 2018. The Brief Case: An unusual cause of infective endocarditis after a urological procedure. J Clin Microbiol 56:e01400-17.