Infection
Case Report
Vertebral Osteomyelitis and Endocarditis of a Pacemaker Lead Due to Granulicatella (Abiotrophia) adiacens O. Rosenthal, A. Woywodt, P. Kirschner, H. Haller
Abstract Systemic infection due to Granulicatella (formerly Abiotrophia), a species of nutrition-deficient gram-positive cocci, is rare. We present the case of a 68-year-old diabetic male who presented with back pain and a history of fever and chills. Imaging studies revealed vertebral osteomyelitis of the Th 10/11 region. Transesophageal echocardiography disclosed a vegetation adjacent to the pacemaker lead and blood cultures grew Granulicatella adiacens. A diagnosis of vertebral osteomyelitis and endocarditis due to G. adiacens was made and the patient improved with bed rest and medical treatment alone. Granulicatella spp. should always be part of the differential diagnosis of fastidious bacteria in vertebral osteomyelitis and endocarditis. Infection 2002; 30: 317-319 DOI 10.1007/s15010-002-2104-3
Introduction Low back pain is among the most frequently encountered problems in medical practice [1]. In the United States, it is the second most frequent reason for visits to the physician who must identify, among vast numbers of patients with degenerative chronic low back pain, the rare case with significant underlying pathology. In this regard, vertebral osteomyelitis remains notoriously difficult to diagnose [2, 3], particularly if the presentation is protean and fastidious bacteria are involved. We report a case of vertebral osteomyelitis and endocarditis of a pacemaker lead due to Granulicatella (formerly Abiotrophia) adiacens, a slowly growing gram-positive coccus. We discuss the biology and classification of Granulicatella and provide a brief review of human infection due to this rare species of fastidious gram-positive cocci.
Case Report A 68-year-old male patient presented with a short history of severe, continuous pain on both sides of his thoracolumbar spine. Moreover, he had recently noted several episodes of fever and chills. He had previously seen a neurologist and a tentative diagnosis of spinal stenosis had been made elsewhere on the basis of
Infection 30 · 2002 · No. 5 © URBAN & VOGEL
a computerized tomography (CT) scan of the lumbar spine. The patient had a complex previous medical history: a longterm diabetic, he was on glibenclamide and acarbose. Bypass grafting had been performed in 1995 for multi-vessel coronary artery disease and unilateral carotid endarterectomy had been carried out the same year. In 1996, the patient had to undergo aortic surgery with prosthetic replacement of the infrarenal aorta after a stent placement had failed. A VVI pacemaker had been fitted in 1998 for symptomatic slow atrial fibrillation and atrioventricular conduction block; the patient was a retired car mechanic and had enjoyed a good quality of life prior to his current presentation. On examination he was afebrile and did not appear acutely ill; the lower thoracic spine was tender to firm palpation. The remainder of the clinical examination was unremarkable and there was no focal neurological deficit. Laboratory results showed a markedly elevated erythrocyte sedimentation rate (ESR 68/ 120 mm); leukocytes were 10 103/µl and hemoglobin 11.9 g/dl. C-reactive protein (CRP) was 140 mg/l, which declined to almost normal values without treatment during the 1st few days in hospital; the patient had no further episodes of fever. Pyogenic vertebral osteomyelitis was considered despite a previous diagnosis of spinal stenosis. Aortic dissection was regarded as another possibility in view of the patient’s extensive vascular disease and history of aortic aneurysm. A CT scan of the thoracic spine showed increased radiolucency of the Th 10/11 intervertebral disc and adjacent vertebrae (Figure 1). A bone scan demonstrated increased tracer uptake in that region. A CT-guided biopsy of the Th 10/11 intervertebral disc failed to yield a sufficient amount of material. Numerous blood cultures were drawn which after 1 week repeatedly grew G. adiacens. The organism was identified by a bioMérieux Rapid ID 32 Strep System (identification probability 99.9%, numerical identification profile 01002101020, bioMérieux, Marcy l’Etoile, France) and subsequent growth on different media. A search was made for possible sources of infection. In particular, there was no evidence of diabetic foot or soft tissue infection; dental examination was unremarkable. Transoesophageal echocardiogram, however, showed a vegetation adjacent to the pacemaker lead (Figure 2). A diagnosis of vertebral osteomyelitis O. Rosenthal, A. Woywodt (corresponding author), H. Haller Division of Nephrology, University of Hannover School of Medicine, Hannover, Germany; Phone: (+49/511) 532-6319, Fax: -52366, e-mail:
[email protected] P Kirschner Dept. of Microbiology, University of Hannover School of Medicine, Hannover, Germany Received: June 6, 2001 • Revision accepted: February 16, 2002
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Figure 1. Frontal reconstruction of the Th 10/11 region from a CT scan; note the destruction (white arrow) of the intervertebral disc and adjacent bone.
and endocarditis due to G. adiacens was made.Treatment with bed rest, penicillin (30 106 U), rifampin (600 mg) and gentamicin (260 mg) was begun. Susceptibility testing later revealed low-level resistance to gentamicin (MIC 8 g/l, E-test, AB Biodisk, Solna, Sweden), whereas it proved susceptible to penicillin, ampicillin, oxacillin, cefazolin, ceftriaxone, erythromycin, clindamycin, vancomycin, rifampin and levofloxacin (disk diffusion susceptibility testing adapted from DIN 58940/3 using chocolate agar incubated at 5% CO2 atmosphere); gentamicin was therefore discontinued. The patient made an uneventful recovery with marked improvement of his low back pain; he did not experience any further episodes of fever or chills.When last seen in March 2001, 6 months after cessation of antibiotic treatment, he was well and afebrile but still reported some residual back pain; CRP, full blood count and ESR were all normal. A follow-up transoesophageal echocardiogram was unremarkable. A CT scan of the spine did not show any evidence of ongoing infection.
Discussion Pyogenic vertebral osteomyelitis is defined as bacterial infection of the vertebral bodies and intervertebral discs [3]. Bacterial pathogens can reach the spine by three routes; contiguous spread from adjacent tissue, direct inoculation or hematogenous spread. In the latter case, which is by far the most common route, organisms reach the vertebral body first and then spread to the disk space. Signs and symptoms may be vague or misleading, hence the diagnosis is often overlooked at the initial presentation [2]. Obtaining a microbiological diagnosis is mandatory in vertebral osteomyelitis; in our patient, blood cultures grew G. adiacens (formerly A. adiacens [4]). The genus Granulicatella was recently defined and divided into three groups: G. adiacens, Granulicatella balaenopterae and Granulicatella elegans. The genus Abiotrophia now remains restricted to Abiotrophia defectiva [5]. Granulicatella spp. are part of the genital, oral and intestinal flora in humans and animals. These organisms are difficult to cultivate owing to
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Figure 2. Echocardiography showing a vegetation adjacent to the pacemaker lead within the right ventricle (white arrow).
their deficiency in nutritive properties, hence the former term nutrition-variant or nutritionally deficient streptococci [6]. Granulicatella spp. can be identified on the basis of their biochemical properties, such as production of chromophore and pyrrolidonyl arylamidase, and their dependence on pyridoxal for growth [7]. Granulicatella spp. have been isolated as the causative organism in a variety of infectious disorders such as meningitis due to lumbar puncture [8], ophthalmic infection [9] and neutropenic fever [10]. Our patient sustained endocarditis and vertebral osteomyelitis due to G. adiacens; to the best of our knowledge, only one case of vertebral osteomyelitis due to the genus has been reported to date [11]. Granulicatella spp. are more frequently encountered as a causative agent of endocarditis [12]. In fact, endocarditis is the most common infection due to Granulicatella and may be under-reported owing to the difficulties in growth and culture of the organism. Thus, some cases of “culture-negative” endocarditis may in fact be due to Granulicatella [13]. It has been suggested that endocardiac infectivity of the organism correlates with its ability to bind extracellular matrix proteins such as fibronectin [14]. In our patient, endocarditis of a pacemaker lead was readily identified. Osteomyelitis, which was also present in the patient reported here, is not infrequently encountered as a complication of infective endocarditis [15]. Our patient made an uneventful recovery after medical treatment alone although removal of the infected lead is commonly advocated.The vast majority of Granulicatella isolates are susceptible to clindamycin, rifampin and ofloxacin [16] yet a high incidence of complications and treatment failure despite appropriate susceptibility testing has been reported [17]. In our patient, follow-up transesophageal echocardiography failed to detect any residual vegetation and removal of the pacemaker lead was therefore withheld.
Infection 30 · 2002 · No. 5 © URBAN & VOGEL
O. Rosenthal et al. Endocarditis and Osteomyelitis Due to Granulicatella
In summary, the case under discussion illustrates the importance of repeated blood cultures, augmented by a high degree of suspicion, and close liaison with a microbiologist in tackling infections due to slowly growing organisms such as Granulicatella.
References 1.
2. 3.
4.
5.
6. 7.
Rosomoff HL, Rosomoff RS: Low back pain. Evaluation and management in the primary care setting. Med Clin North Am 1999; 83: 643–662. Lurie JD, Gerber PD, Sox HC: A pain in the back. N Engl J Med 2000; 343: 723–726. Sexton DJ, McDonald M: Vertebral osteomyelitis. In: Rose B (ed.): UpToDate clinical reference library on CD ROM. Release 9.1, UpToDate Inc., Wellesley, 2001. Kawamura Y, Hou XG, Sultana F, Liu S, Yamamoto H, Ezaki T: Transfer of Streptococcus adjacens and Streptococcus defectivus to Abiotrophia gen. nov. as Abiotrophia adjacens comb. nov. and Abiotrophia defectiva comb. nov., respectively. Int J Syst Bacteriol 1995, 45: 798–803. Collins MD, Lawson PA: The genus Abiotrophia ( Kawamura et al.) is not monophyletic: proposal of Granulicatella gen. nov., Granulicatella adiacens comb.nov., Granulicatella elegans comb.nov. and Granulicatella balaenopterae comb.nov. Int J Syst Evol Microbiol 2000; 50: 365–369. Ruoff KL: Nutritionally variant streptococci. Clin Microbiol Rev 1991; 4: 184–190. Kanamoto T, Sato S, Inoue M: Genetic heterogeneities and phenotypic characteristics of strains of the genus Abiotrophia and proposal of Abiotrophia para-adiacens sp. nov. J Clin Microbiol 2000; 38: 492–498.
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8.
Schlegel L, Merlet C, Laroche JM, Fremaux A, Geslin P: Iatrogenic meningitis due to Abiotrophia defectiva after myelography. Clin Infect Dis 1999;28:155–156. 9. Namdari H, Kintner K, Jackson BA, Namdari S, Hughes JL, Peairs RR, Savage DJ: Abiotrophia species as a cause of endophthalmitis following cataract extraction. J Clin Microbiol 1999, 37: 1564–1566. 10. Murray CK, Walter EA, Crawford S, McElmeel ML, Jorgensen JH: Abiotrophia bacteremia in a patient with neutropenic fever and antimicrobial susceptibility testing of Abiotrophia isolates. Clin Infect Dis 2001; 32: 140–142. 11. Heath CH, Bowen SF, McCarthy JS, Dwyer B: Vertebral osteomyelitis and discitis associated with Abiotrophia adiacens (nutritionally deficient streptococcus) infection. Aust NZ J Med 1998; 28: 663. 12. Christensen JJ, Gruhn N, Facklam RR: Endocarditis caused by Abiotrophia species. Scand J Infect Dis 1999; 31: 210–212. 13. Brouqui P, Raoult D: Endocarditis due to rare and fastidious bacteria. Clin Microbiol Rev 2001; 14: 177–207. 14. Okada Y, Kitada K, Takagaki M, Ito HO, Inoue M: Endocardiac infectivity and binding to extracellular matrix proteins of oral Abiotrophia species. FEMS Immunol Med Microbiol 2000; 27: 257–261. 15. Ninet J, Gayet JL, Etienne J, Bonvoisin B, Vignon E, Berthou JD, Delahaye JP, Pasquier J, Delaye J, Normand J: Bacterial endocarditis presenting as acute vertebral osteomyelitis: 14 cases. Eur Heart J 1984; 5 (suppl C): 101–105. 16. Tuohy MJ, Procop GW, Washington JA: Antimicrobial susceptibility of Abiotrophia adiacens and Abiotrophia defectiva. Diagn Microbiol Infect Dis 2000; 38: 189–191. 17. Stein DS, Nelson KE: Endocarditis due to nutritionally deficient streptococci: therapeutic dilemma. Rev Infect Dis 1987; 9: 908–916.
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