Aortic Aneurysm Secondary to Streptococcus zooepidemicus

García, F.; Volo, G.; Cabrera, V.

doi:10.1016/j.ejvsextra.2005.11.005

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Volume 11, Issue 5 , Pages 91-93, May 2006

Aortic Aneurysm Secondary to Streptococcus zooepidemicus

Servicio de Angiología y Cirugía Vascular, Hospital de Gran Canaria Dr Negrin, Barranco de la Ballena s/n, 35020 Las Palmas de Gran Canaria, Spain

Accepted 18 November 2005.

Abstract

Infected aortic aneurysms caused by Streptococcus zooepidemicus are rare, difficult to treat and associated with significant mortality. An outbreak associated with this microorganism occurred in our hospital after consumption of unpasteurised milk and dairy products. Twelve patients were admitted for septicemia caused by S. zooepidemicus. We report three patients with infected aortic aneurysms and review the literature.

Keywords: Aortic aneurysm, Streptococcus zooepidemicus, Infected aneurysm

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1. Introduction

The incidence of mycotic aortic aneurysms (MAA) is unknown but probably low. The predominant microorganisms associated are: Salmonella (15%) Staphylococcus aureus (28%) and Streptococcus (10%).

We report an outbreak produced by Streptococcus zooepidemicus in Gran Canaria in March 2004, with a total of 12 patients. This report describes our experience with three patients who presented with MAA (Table 1).

Table 1.

Age/sex	Underlying disease	Presenting syndrome	Outcome
59/M, present report	Hypertension (HTA), diabetes mellitus (DM)	Abdominal aortic aneurysm infection	Well with iv antibiotics and insertion of bifurcated Dacron graft
68/M, present report	HTA, DM, chronic obstructive airway disease	Suprarenal aortic aneurysm infection	Died despite iv antibiotics and insertion of bifurcated graft
69/M, present report	HTA, DM	Thoracic aortic aneurysm infection	He died of sepsis despite of thoracic endograft and antibiotics
62/M, Yuen¹	Cirrosis of the liver portal hypertension	Abdominal aortic aneurysm infection	Died despite iv antibiotics and insertion of bifurcated graft
65/M, Albarracin³		Abdominal aortic aneurysm infection	Well with iv antibiotics and insertion of bifurcated Dacron graft
73/M, Yuen¹	Atrial fibrillation	Abdominal aortic aneurysm infection	Well with iv antibiotics and insertion of bifurcated Dacron graft
M, Rhomberg²	Appendectomy	Abdominal aortic aneurysm infection	Well with iv antibiotics and insertion of bifurcated Dacron graft
M, Yuen¹	Abdominal aortic	Abdominal aortic aneurysm infection	Died despite iv antibiotics

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2. Case Reports

1.A 69-year-old man who had consumed fresh cheese. Before his admission he complained of back pain and fever. Abdominal ultrasound scan and blood cultures were normal. He was treated with antibiotics. He was hemodynamically stable, WBC: 13×10³

μL and Hb 8.2

g/dL (previous 9.8). A CT revealed a 7.7

cm descending thoracic aneurysm (TAA) with a contained rupture. Talent thoracic endograft was positioned (Fig. 1). Completion angiography showed good positioning of the endograft and no signs of endoleak. Nine days later he presented convulsions and fever. Three blood cultures were positive for S. zooepidemicus. Penicillin and gentamicin were administered intravenously but he died of sepsis 2 days later.

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Fig. 1.
Descending thoracic aortic aneurysm 7.7cm with a contained ruptured.

2.A 59-year-old man who had consumed fresh cheese. Before his admission he complained of abdominal pain and fever. Ciprofloxacin was administered during 10 days without improvement. He was hemodynamically stable and his temperature was 37

°C. WBC: 7.7×10³

μL and Hb 14

g/dL. Three blood cultures were positive for S. zooepidemicus. Penicillin and gentamicin were administered intravenously without improvement. A CT revealed a 9.6

cm infrarenal aneurysm (Fig. 2). He was taken to surgery and aorto-bifemoral graft was placed. He completed 3 weeks of intravenous antibiotics. Cultures of the aneurysmal wall were negative. Oral trimethoprim–sulfamethoxazole was administered for 6 months. At 12 months follow-up he was well and living independently.

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Fig. 2.
CT scan revealing 9.6cm infrarenal abdominal aortic aneurysm.

3.A 68-year-old man who had consumed fresh cheese. He complained of abdominal and back pain, and fever. WBC 22×10³

μL, and Hb 14.2

g/dL. Three blood cultures were positive for S. zooepidemicus. Penicillin and gentamicin were administered intravenously without improvement. A CT revealed a 5

cm suprarenal aneurysm. Aorto-aortic graft was placed and left renal artery was reimplanted. Three days later he was hemodynamically unstable. A CT revealed a small intestine infarction. Laparatomy was performed and fatal small intestinal necrosis was discovered. He died 3

h later.

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3. Discussion

S. zooepidemicus infection is a common in animals but rare cause in humans. Outbreaks of severe infection in people consuming unpasteurized milk and dairy products have been described. Cases usually present with meningitis, pneumonia, septic arthritis, septicaemia or glomerulonephritis. Consumption of unpasteurized milk or milk products was implicated as the source of infection in this outbreak.

We found only five cases of aneurysms of the abdominal aorta due to S. zooepidemicus published in literature.¹, ², ³ We describe the first case of TAA secondary to S. zooepidemicus and repaired by stent-grafting. The others cases were underwent surgery with aortic repair and intravenous antibiotics.

Blood cultures may be negative, particularly when the patient received antibiotic therapy. Blood cultures were positive in two cases. In the third case the blood cultures were sterile before the operations but grew S. zooepidemicus in the postoperative period.

Aortogram and CT (multilobular appearance and periaortic gas) were suggestive of MAA in the second or third patient. However, in the first case, despite the patient was pyrexial and the WBC was 13,000, blood cultures were negative preoperatively and the radiological findings were not clearly indicative of MAA. In this case a thoracic endograft was positioned.

Optimal management includes early diagnosis, with timely surgical intervention and prolonged antibiotic treatment. We found that in situ reconstruction is a safe option. Recents series continue to report a high incidence of complications with extra-anatomic reconstruction.⁴, ⁵ In the last decade, endovascular stent-grafting has gained growing acceptance as an alternative treatment of MAA. The choice of the ideal conduit is still controversial.

Careful long-term follow-up is a important element in the treatment. We perform a CT before discharge, every 3 months for 1 year, and annually thereafter. Clinical signs of recurrent infection, should prompt further investigations (WBC, blood cultures, CT).

We advocate the intravenous use of two synergistic antibiotics, because of the invasive potential of S. zooepidemicus and the associated poor prognosis. We used B-lactamic and aminoglycosides intravenously during a 3 weeks followed by long-term suppression with oral antibiotic during 6 months (ciprofloxacin for MAA caused by Gram-negative and trimethoprim–sulfamethoxazole caused Gram-positive). There are no prospective studies addressing the optimal duration of antibiotic therapy after surgical resection. Despite the antibiotherapy is an essential element, we must not forget that success depends on an early surgical treatment.

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References

Yuen KJ, Seto WH, Choi CH, Ng W, Chau PY. Streptococcus zooepidemicus (Lancefield group C) septicaemia in Hong Kong. J Infect. 1990;21:241–250

Rhomberg M, Allerberger F, Mittermair M, Flora G. Mycotic aortic aneurysm after appendectomy. Vasa. 1996;25(1):90–93
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Albarracin C, Rosencrance G, Boland J. Bacteremia due to Streptococcus zooepidemicus associated with an abdominal aortic aneurysm. W V Med J. 1998;94(2):90–92
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- MEDLINE