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Case report
A case of bacteriemic mediastinitis due to Prevotella buccae after cardiac surgery C. Duployez a, C. Loiez a, R. Hund a, B. Jegou b, C. Decoene b, F. Wallet a, * a b
CHU Lille, Service de Bact eriologie-Hygi ene, Centre de Biologie-Pathologie, F-59000, Lille, France CHU Lille, Service de Chirugie Cardio-Vasculaire, Institut Cœur Poumon, F-59000, Lille, France
a r t i c l e i n f o
a b s t r a c t
Article history: Received 1 April 2019 Received in revised form 28 August 2019 Accepted 2 September 2019 Available online xxx
Mediastinitis is a well-known complication of open-heart surgery. Strictly anaerobic bacteria are rarely found in this condition, unlike in descending mediastinitis. We report the case of a mediastinitis due to Prevotella buccae after surgical replacement of the aortic valve and triple coronary artery bypass in an immunocompetent 76 year-old man. The bacteria were found in pure culture on blood samples and surgical samples. This case emphasizes the need to perform anaerobic cultures in case of sternal wound infection after open-heart surgery. © 2019 Elsevier Ltd. All rights reserved.
Handling Editor: Hanna Pituch Keywords: Mediastinitis Cardiac surgery Anaerobes P. buccae
1. Introduction Post-operative mediastinitis is a classic complication of openheart surgery, occurring with an incidence of 1.3% [1]. Coagulasenegative staphylococci or Staphylococcus aureus are isolated from the majority of the patients (46% and 26%, respectively). In these cases of mediastinitis, strictly anaerobic bacteria are unfrequent whereas mixed infections due to both aerobic and anaerobic microorganisms are found in case of mediastinitis secondary to extension from head and neck sources. We report a case of nosocomial mediastinitis due only to P. buccae after open-heart surgery in an immuno-competent patient. 2. Case report A 76 year-old man consulted the cardiologic ward for recently increasing dyspnea (NYHA II). His medical history included smoking, chronic renal failure, atherosclerosis, ischemic stroke, peripheral arterial disease, and a significant aortic valve stenosis. At
riologie - Institut de Microbiologie, * Corresponding author. Laboratoire de Bacte Centre de Biologie Pathologie, F-59037, Lille Cedex, France. E-mail addresses:
[email protected] (C. Duployez), caroline.loiez@ chru-lille.fr (C. Loiez),
[email protected] (F. Wallet).
admission, he was apyretic. His blood pressure was 130/80 mm Hg. The surgical replacement of the aortic valve was retained because the ejection fraction was measured at 65% combined to a triple coronary artery bypass because the coronarography showed three strict stenosis of the arteries. The analytical profile demonstrated a normal leukocytosis (8.7 109/l; 53.4% neutrophils) and a C-reactive protein concentration < 3 mg/l. After 5 post-surgical days, the patient suffered from clinical sepsis with fever (38.4 C), elevated leukocytosis (23.54 109/l; 80% neutrophils), and a C-reactive protein concentration of 132 mg/l. Post-operative mediastinitis was suspected given association of these signs with purulent discharge from the mediastinal wound. Four blood cultures sets (aerobic and rieux, Marcy l’Etoile, anaerobic bottles) (Bact-Alert3D, BioMe France) were performed before antibiotic therapy introduction. The patient underwent a revision surgery 2 days later for drainage of the pericardial cavity and bacteriological sampling (sternal bone and pre-sternal liquid). An empirical post-operative antibiotic therapy consisting of piperacillin-tazobactam and daptomycin were introduced until the results of intraoperative sample cultures were available. Sternal bone and pre-sternal liquid abscess were sent to the bacteriology laboratory. Direct examination showed no bacteria on the Gram-stain, but a high number of leukocytes was observed. The four anaerobic bottles sampled and surgical samples were detected
https://doi.org/10.1016/j.anaerobe.2019.102097 1075-9964/© 2019 Elsevier Ltd. All rights reserved.
Please cite this article as: C. Duployez et al., A case of bacteriemic mediastinitis due to Prevotella buccae after cardiac surgery, Anaerobe, https:// doi.org/10.1016/j.anaerobe.2019.102097
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as positive after 4 and 6 days of incubation, respectively. The surgical sample yielded only in anaerobic atmosphere giving a monoculture of Gram negative rod. P. buccae was identified using MALDI-TOF spectrometry mass (Bruker Daltonics, Wissembourg, France) with a score ¼ 2.22. In vitro susceptibility tests, using E test de strips, were performed according to CA-SFM 2019 (Comite te Française de Microbiologie; http:// l'Antibiogramme de la Socie www.sfm-microbiologie.org) recommendations. Our isolate was classified as resistant to amoxicillin (MIC ¼ 32 mg/L) and susceptible to amoxicillin-clavulanic acid (MIC ¼ 0.5 mg/L), piperacillintazobactam (MIC ¼ 0.032 mg/L), imipenem (MIC ¼ 0.032 mg/L), clindamycin (MIC ¼ 0.016mg/L), rifampicin (MIC < 4 mg/L), metronidazole (MIC ¼ 0.125 mg/L). Revision surgery and antibiotic therapy were effective with resolution of fever and decrease of leukocytosis and C-reactive protein levels. The purulent discharge from the sternotomia stopped. Finally, the patient made a complete recovery. 3. Discussion P. buccae is a Gram-negative anaerobic bacillus, being part of the normal human oral flora. Thus, it is mainly involved in pulmonary abscesses and their complications, often in mixed infections, as for other anaerobic bacteria [2]. In the literature, only few cases of monomicrobial infections with P. buccae have been reported [3]. In the same way as for these cases, isolation of P. buccae in pure culture in our samples confirms with certainty its pathogenic role in the disease. In most cases, mediastinitis occurs as post-operative infections after cardiac surgery. They are primarily caused by Gram-positive cocci, especially coagulase-negative staphylococci or S. aureus, and bacteria of the Enterobacteriales family [1]. Conversely, anaerobic bacteria are preferentially involved in mediastinitis following oesophageal perforation, extension of retropharyneal abscess, suppurative parotitis, cervical cellulitis or abscess of dental origin [4]. A review of the medical literature about descending necrotizing mediastinitis found a majority of polymicrobial infections with aerobic (especially Streptococcus spp) and anaerobic bacteria (especially Peptostreptococcus spp, Bacteroides fragilis, Prevotella spp and Fusobacterium spp), bacteria reflecting the flora of the oral cavity: the large Japanese study of Sumi about 89 case reports shows this polymicrobial aspect [5]. Recently, Lareyre et al. described a fatal aortic arch rupture complicating a descending necrotizing mediastinitis resulting from cervical necrotizing fasciitis. Blood cultures yielded a monomicrobial culture of P. buccae and cervical and pleural abscesses were polymicrobial [6]. In a prospective study by Palma et al. including 20 microbiologically documented cases of descending necrotizing mediastinitis, Prevotella spp was implicated in 5 cases, associated either with S. aureus or with K. pneumoniae [7]. Presence of anaerobic bacteria (and of Prevotella spp) in postcardiac surgery mediastinitis is more uncommon. Few cases of post-operative mediastinitis are related [8e10]. Among these 29 cases, 20 were polymicrobial and the anaerobic bacteria most frequently isolated were Peptostreptococcus spp (16/29) and Bacteroides spp (10/29). Prevotella spp was isolated only in 2 anaerobicpolymicrobial post-sternotomy mediastinitis in children of 2 and 7 years old [11]. To our knowledge, our case is the first description of monomicrobial P. buccae post-car mediastinitis. Our patient had several risk factors commonly associated with
post-cardiac surgery bacteriemic mediastinitis such as peripheral arterial disease, smoking, and use of internal mammary artery [12]. However, origin of this infection was not found and we assume an hematogenous spread from his oropharyngeal flora, either linked to an oral mucosal injury during intubation or rather to a previous migration to a place with adhesive properties such as the atherosclerosis wall [13]. Despite severity of this disease, 14 of the previously described cases were cured (15 without data about outcomes), which can be partly explained by an appropriate antibiotic therapy thanks to microbiological documentation. Although post-sternotomy mediastinitis caused by anaerobic bacteria is rare, it should be evoked after cardiac surgery, even if an aerobic bacterium is already cultured. In case of post-cardiac surgery mediastinitis, anaerobic cultures must be performed for all microbiological samples taken in this context. Declarations of interest None. Funding source This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. References [1] B. Gårdlund, C.Y. Bitkover, J. Vaage, Postoperative mediastinitis in cardiac surgery - microbiology and pathogenesis, Eur. J. Cardiothorac. Surg. 21 (5) (2002) 825e830. [2] I. Brook, Spectrum and treatment of anaerobic infections, J. Infect. Chemother. 22 (1) (2016) 1e13, https://doi.org/10.1016/j.jiac.2015.10.010. [3] F. Cobo, J. Rodríguez-Granger, A. Sampedro, J.M. Navarro-Marí, Infected breast cyst due to Prevotella buccae resistant to metronidazole, Anaerobe 48 (2017) 177e178, https://doi.org/10.1016/j.anaerobe.2017.08.015. [4] I. Brook, The role of anaerobic bacteria in mediastinitis, Drugs 66 (3) (2006) 315e320. [5] Y. Sumi, Descending necrotizing mediastinitis: 5 years of published data in Japan, Acute Med. Surg. 2 (1) (2014) 1e12, https://doi.org/10.1002/ams2.56. eCollection 2015 Jan. [6] F. Lareyre, C. Cohen, S. Declemy, J. Raffort, H. Quintard, A fatal aortic arch rupture due to descending necrotizing mediastinitis in a 24-year-old woman, Vasc. Endovasc. Surg. 51 (6) (2017) 408e412, https://doi.org/10.1177/ 1538574417715193. [7] D.M. Palma, S. Giuliano, A.N. Cracchiolo, M. Falcone, G. Ceccarelli, R. Tetamo, et al., Clinical features and outcome of patients with descending necrotizing mediastinitis: prospective analysis of 34 cases, Infection 44 (1) (2016) 77e84, https://doi.org/10.1007/s15010-015-0838-y. is, M. Mat, A.B. Hoï, I. Podglajen, L. Gutmann, A. Novara, et al., Post[8] S. Kerne operative mediastinitis due to Finegoldia magna with negative blood cultures, J. Clin. Microbiol. 47 (12) (2009) 4180e4182, https://doi.org/10.1128/ JCM.01192-09. [9] D. Radermecker, I. Michaux, Y. Louagie, A. Dive, Prostatic abscess associated with Bacteroides fragilis mediastinitis after heart surgery, Interact. Cardiovasc. Thorac. Surg. 10 (4) (2010) 659e660, https://doi.org/10.1510/ icvts.2009.225102. ry-Arnaud, C.H. David, B. Provost, P. Mondine, Z. Alavi, et [10] C. De Moreuil, G. He al., Finegoldia magna, not a well-known infectious agent of bacteriemic poststernotomy mediastinitis, Anaerobe 32 (2015) 32e33, https://doi.org/ 10.1016/j.anaerobe.2014.11.012. [11] I. Brook, Recovery of anaerobic bacteria from four children with postthoracotomy sternal wound infection, Pediatrics 108 (1) (2001) E17. [12] T.C. Van Schooneveld, M.E. Rupp, Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, seventh ed., 1, 2010, pp. 1173e1182, 82 Mediastinitis. [13] J. Mahendra, L. Mahendra, A. Nagarajan, K. Mathew, Prevalence of eight putative periodontal pathogens in atherosclerotic plaque of coronary artery disease patients and comparing them with noncardiac subjects: a case-control study, Indian J. Dent. Res. 26 (2) (2015) 189e195, https://doi.org/10.4103/ 0970-9290.159164.
Please cite this article as: C. Duployez et al., A case of bacteriemic mediastinitis due to Prevotella buccae after cardiac surgery, Anaerobe, https:// doi.org/10.1016/j.anaerobe.2019.102097